What is Brazing-Principles

Discovering Brazing (Braze Welding)


Brazing is a gas welding process in which you join metals by using heat that surpasses the 800 degree Fahrenheit mark and a nonferrous (iron-free) filler rod with a melting temperature below that of the base materials. The most important point about brazing is that you can use it to join dissimilar metals — cast iron to steel, brass to steel, or copper to steel, just to name a few examples.

Keeping a few brazing rules in mind
A successful brazing job requires that you stick to a few rules, as follows:

✓ The surfaces of the metals must be free of contaminants. Use steel wool to clean off all the metals, and use flux (a material that dissolves or removes oxides and other contaminants from the surface during brazing) for additional cleaning when the surfaces are heated.
✓ The joint to be brazed must have a tight fit. You use two basic joints for brazing: the butt joint (two pieces of material lying together on the same plane) and the lap joint (two pieces of material overlapping each other, usually in a parallel plane). If the joint has sizeable gap, brazing just doesn’t work. But if the joint is too tight, the melted filler rod can’t penetrate the entire joint, and you get a weak, ineffective weld.
✓ The base metals you’re brazing must remain stationary during the
heating and cooling process. If the base metals move while you’re welding or before everything has cooled off after welding, the joint’s integrity will likely be compromised


Giving brazing a try
If you’re trying brazing for the first time, I recommend going with an oxyacetylene torch in the flat position and using the forehand method I discuss in “Making the weld” earlier in the chapter. You can start by creating a brazed corncob, which is a piece created when you join two different metals,
following the steps in this section.

Brazing principles 

1. Acquiring a section of carbon steel pipe 1 inch in diameter and five inches long, as well as four 1⁄8-inch fluxed brazing filler rods that are 36 inches long.

2. Clean the pipe thoroughly with steel wool to remove any contaminants on the surface.

3. Lay the pipe between two fire bricks, leaving a 3⁄4-inch space between the bricks.
Fire bricks are special bricks that can withstand extremely high temperatures; find them at your welding supply or hardware store.
4. Set up and light the oxyacetylene torch, using the steps I describe in “Working through the Basics of Welding with Gas” earlier in this chapter, and adjust the torch so you have a neutral flame.
5. Preheat the pipe to burn off any grease or varnish that may be left on
the surface.
6. If you’re right-handed, start on the right end of the pipe and melt off a small portion of the filler rod onto the end of the pipe. If you’re left-handed, start on the left end of the pipe. The molten puddle should be very fluid. Be sure that when you use more of the filler rod, you let only the molten puddle (not the flame from the torch) melt the rod. If you notice white smoke coming from your molten puddle, that means you’re burning the zinc out of your filler rod, which will result in a poor
weld. Avoid that problem by welding at a lower temperature or moving more quickly with the molten puddle. When you’re practicing the brazing process, you can quench the metal between passes with the torch. Use pliers to pick up the section of pipe you’re practicing on and place it in a tank of water to cool it very quickly. Quenching isn’t good for the integrity of the brazed weld, though, so don’t quench unless you’re just practicing.

7. After you make your first pass with the torch, start a second pass by pointing the tip of the flame at the edge of the previous pass; when part of the first braze starts to melt, add some of your filler rod and proceed. This pass laps over the first braze bead 1⁄3 to 1⁄5.

8. When you’ve completed your second pass, quench the welded metal (or allow it to cool) and go ahead and start on a third pass. When you’re finished with the third pass, you should have a finished
product that resembles the brazed corncob in Figure 13-3. For some brazing projects, you may need to make even more passes. (For example, projects involving thick pieces of metal definitely require more than three passes.)

Please Read :

• Different types of welding defects.
• How to easily understand TIG welding Basics 
• Advantages of TIG welding 
• TIG welding Principles in Easy language 
• Welding Electrodes Explained 
• MIG welding principles 
• Aluminothermic or Thermit Welding Principles  
• Submrged Arc Welding 
• Flux shielded metal arc welding process principles 
• Resistance Projection Welding 
• Resistance Spot Welding 
• Resistance Seam Welding 
• TIG Aluminum Welding Advantages  made easy !
• Advanced TIG welding operations 

Read full post »

Magnetically Impelled Arc Butt Welding Principles

Magnetically impelled arc butt (MIAB) welding (sometimes referred to as rotating arc welding) is a rapid, clean, and reliable arc welding process that employs forging to produce  the finished weld. As such, it is classified as an electric arc welding process since that is the energy source for producing melting or fusion, even though pressure from forging is needed to complete the weld. It is thus a fusion arc pressure welding process, and, in that way, is related to arc stud welding  ( not described in this article. )

The MIAB welding process is well established in Europe (especially Eastern Europe) and the independent  states of  the  former Soviet Union, finding application in  the  automotive  industry for  the fabrication of tubular-section butt welds and, to a lesser extent, tube-to-plate welds. Tubes can have circular or non-circular cross sections, with walls ranging from 0.5 to 5 mm or more (0.020 to 0.200 in.) thick. Steel as well as aluminum alloy has been  welded successfully in mass production, producing welds with exceptional quality even for safety-critical applications.

Magnetically Impelled Arc Butt Welding Principles 

In practice, MIAB welding  is fully automated. An arc drawn between aligned but properly gapped tube ends is impelled to move (rotate) around the joint  line by an interaction of  the arc current  and  an externally  applied magnetic field , hence the name. Once the arc has heated the ends of the tubes to cause localized melting and adjacent softening in the heat-affected zone, the parts are forged together. This expels most of the molten metal present and a solid-phase  bond is formed. The principle of operation is shown  schematically in  Figure 1 ; typical placement of the magnets used to apply the propelling force to the arc is shown in Figure 2

Figure 1 : MIAB principles 

Figure 2 : MIAB schematic 

Benefits of MIAB

The  major benefits of MIAB welding are (1)  no rotation of either  component  (thereby  overcoming  problems  with  asymmetrical  parts  encountered with many friction welding processes), (2) short welding times (e.g., 2-4 s for 2 to 4-mm CO.040-  to 0.080-in.]-thick low-carbon steel tube), (3) low
material loss, (4) low fumes and  spatter, and (5) relatively low required arc current.

As opposed to flash and upset welding , MIAB welding does not use resistance to accomplish heating at the joint, but, rather, an electric arc. This makes  it an arc rather  than a  resistance welding process. The fact that forging  removes  most  molten  metal  suggests that  the  process  could  be considered non-fusion; after  all,  the role of the  liquid is  largely  fluxing . The  process is considered  a  non-consumable electrode arc process because the intent is not to consume the parts being welded and used as electrodes, but to preserve those parts.

Please Read :

• Different types of welding defects.
• How to easily understand TIG welding Basics 
• Advantages of TIG welding 
• TIG welding Principles in Easy language 
• Welding Electrodes Explained 
• MIG welding principles 
• Aluminothermic or Thermit Welding Principles  
• Submrged Arc Welding 
• Flux shielded metal arc welding process principles 
• Resistance Projection Welding 
• Resistance Spot Welding 
• Resistance Seam Welding 
• TIG Aluminum Welding Advantages  made easy !
• Advanced TIG welding operations 

Read full post »

Abrasive Jet Machining (AJM) Process Advantages and Disadvantages

Abrasive Jet Machining (AJM) Principles 

In abrasive jet machining process, a focused steam of abrasive particles (of size 10 to 40 microns) carried by high pressure gas or air at a velocity of about 150 to 300 m/sec is made to impinge on the work surface through a nozzle, and the work material is removed by erosion by the high velocity abrasive particles. The inside diameter (ID) of the nozzle through which abrasive particles flow is about 0.18 to 0.80 mm and the stand-off distance (i.e. distance between nozzle tip and workpiece) is kept about 0.3 to 20.0 mm. The process can be easily controlled to vary the metal removal rate which depends on flow rate and size of abrasive particles. This process is best suited for machining super alloys and refractory type of materials, and also machining thin sections of hard materials and making intricate hard holes. The cutting action is cool because the carrier gas serves as coolant. 

When an abrasive particle (like Al2O3 or SiC) having sharp edges hits a brittle and fragile material with a high speed, it makes dent into the material and lodges a small particle from it by a tiny brittle fracture. The lodged out or wear particle is carried away by the air or gas. The operating elements in AJM are abrasive, carrier gas and the nozzle as schematically shown in the following Figure

Abrasive Jet Machining (AJM) Principles 

The distance between the nozzle tip and the work surface has great influence on the diameter of cut, its shape and size and also rate of material removal. The following Figure shows the variation in the diameter of cut with change in the stand off distance (SOD). It is evident that the SOD changes the abrasive particles spreads (i.e. covers wider area) on the work surface and consequently increases the diameter of the cut.

The basic Units of AJM

The basic unit is schematically shown in following Figure. It consists of gas supply system (compressor), filter, pressure regulator, mixing chamber, nozzle assembly and the work holding device. In the mixing chamber, the abrasive is allowed to flow into the gas stream. The mixing ratio is generally controlled by a vibrator. The particle and gas mixture comes out of the nozzle inside the machining chamber of the machine tool unit. The feed motion can be given either to the work holding device or to the nozzle. 

AJM setup

Please read :

• Water Jet Machining Process .
• Laser Beam Machining 
• Electrical Discharge Machining (EDM) Principles 
• Electrochemical machining process 

Abrasive Jet Machining (AJM) Advantages:

• This process is quite suitable for machining brittle, heat resistant and fragile materials like, glass, ceramic, germanium, mica etc. 
• It can be utilized for cutting, drilling, polishing, deburring, cleaning etc. of the materials. 
• The depth of damage to the surface is very little. 
• Holes of intricate shapes could be produced efficiently.
• The surface machined can have good finish (by controlling the grain size mainly). 

AJM Disadvantages: 

The materials removal rate is low. For example, for glass, it is 0.0164 cm3/min. 

• The tapering of hole especially, when the depth of the hole is more, becomes almost inevitable. 
• A dust collecting chamber is a basic requirement to prevent atmospheric pollution to cause health hazards.
• The abrasive particles may remain embedded in the work surface. 
• Abrasive particles cannot be reused.

AJM Applications:

• Abrasive jet machining is best suited for machining brittle and heat sensitive materials like glass, quartz, sapphire, ceramics etc,
• It is used for drilling holes, cutting slots, cleaning hard surfaces, deburring, polishing etc. 

Please Read :

• Different types of welding defects.
• How to easily understand TIG welding Basics 
• Advantages of TIG welding 
• TIG welding Principles in Easy language 
• Welding Electrodes Explained 
• MIG welding principles 

Read full post »

Gas Tungsten Arc Welding (GTAW)-TIG welding operations

Gas-tungsten arc welding (GTAW) uses a permanent,  non-consumable tungsten electrode to create an arc to a workpiece. This electrode is shielded by an inert gas, such as argon or helium (or a mixture of the  two), to prevent electrode degradation; hence the older, common names tungsten-inert  gas (TIG) and heli-arc welding. As shown in Figure below, current from the power supply is passed to the tungsten electrode of a torch  through a contact tube. This tube is  usually (but may not be) water-cooled to prevent overheating. The gas- tungsten arc welding process can be performed with or without filler (autogenously). When no filler  is employed, joints must  be thin and have a close fitting square-butt configuration.

Please Read :

• Different types of welding defects.
• How to easily understand TIG welding Basics 
• Advantages of TIG welding 
• TIG welding Principles in Easy language 
• Welding Electrodes Explained 
• MIG welding principles 

Gas Tungsten Arc Welding (GTAW)- Tungsten Inert Gas (TIG) welding current or operating modes  

The GTAW process, as well as several other  arc welding processes (e.g., SMAW, GMAW, and FCAW), can be operated in several different current modes, including  direct current (DC), with the  electrode negative (EN) or positive (EP), or alternating  current (AC). These different
current or power modes result in distinctly different arc and weld characteristics. When the workpiece or weldment is connected to the positive (+) terminal of a direct current  power supply, the operating mode is referred to as direct current straight polarity (DCSP) or direct current electrode negative DC - or DCEN). When the workpiece is connected to the negative terminal of a direct current power supply,  the  operating  mode is  referred to  as direct  current reverse polarity (DCRP) or direct current electrode positive (DC + or DCEP). In DCSP, electrons are emitted from the tungsten electrode and accelerated to very high speeds and kinetic energies while traveling through  the arc. These high-energy electrons collide with the workpiece, give up their kinetic energy, and generate considerable heat in the workpiece. Consequently, DCSP results in  deep penetrating,  narrow welds, but with  higher workpiece heat input. About  two-thirds of the net heat  available from the arc (after losses from various sources) enters the workpiece. High heat input to the workpiece may or may not be desirable, depending on factors such as required weld penetration,  required weld width, workpiece  mass, susceptibility to  heat-induced defects or degradation, and concern for distortion  or residual stress. In DCRP, on the other hand,  the heating effect of the electrons is on  the tungsten electrode rather  than  on  the workpiece. Consequently, larger water-cooled electrode  holders are required,  shallow welds are produced, and workpiece heat input can be kept low. This operating mode is good for welding thin sections or heat-sensitive metals and alloys. This mode also results in a scrubbing action  on the workpiece by the  large positive ions that strike its surface, removing oxide and cleaning the surface. This mode is thus preferred for  welding metals and alloys that  oxidize  easily,  such as aluminum or magnesium.

Please Read :

• TIG Aluminum Welding Advantages  made easy !

The DCSP mode is much more common with nonconsumable electrode arc processes than  the DCRP mode. There is, however, a third  mode, employing alternating  current or AC. The AC mode  tends to result in  some of  the characteristics of both of the DC modes, during the corresponding half cycles, but with some bias toward  the straight  polarity half-cycle due to the greater inertia (i.e., lower mobility) and, thus, greater resistance of large positive ions. During this half-cycle, the current tends to be higher due to the extra emission of electrons from the smaller, hotter electrode versus larger, cooler workpiece. In the AC mode, reasonably good  penetration is obtained, along with some
oxide cleaning action. Figure below summarizes the characteristics of the various current or operating modes of the  GTAW process  described  above. (Incidentally, many of these effects are far less pronounced with other electric arc welding  processes employing consumable electrodes. Most particularly, there is little difference in penetration between DCSP and DCRP. This is so since the concentration of heat at the electrode with RP aids in melting the consumable electrode, as is
desired, but this heat is returned to the weld when the molten metal droplets transfer to the pool. On the other hand, the cleaning action of the RP mode at the workpiece still takes place.)

TIG Welding at Various Currents Diagram 

In modern welding power  supplies designed specifically for GTA welding, there is the added capability for square-wave AC and for wave  balancing. In square-wave AC, solid-state  electronic devices reshape  the  sinusoidal wave provided as  input to the power supply from  line voltage to give it a square shape; positive for half a cycle and negative for half a cycle. This shape turns out to be advantageous during the transition from one half-cycle to the other, where the  voltage  and  resulting current pass through  zero. For normal sinusoidal waveforms, as this transition is taking place, the voltage just before and just after the reversal approaches zero relatively slowly compared to the rate of change for a square wave. The effect of the much more rapid (essentially instantaneous) reversal with a square wave is to avoid possible momentary loss and subsequent difficulty of reestablishing the arc.
In wave balancing, there is the capability of shifting the relative magnitude of the straight and reverse half-cycles, thereby shifting the characteristics of the altered waveform. This is done by applying a DC bias  voltage to the AC, whether of sinusoidal or square waveform. The  advantage is the ability to fine-tune the waveform for the particular material being welded, obtaining just the degree of straight  (penetrating) or reverse (cleaning) half-wave behavior desired.  Regardless of  mode or waveform, power  supplies for GTAW are generally of a constant  current (CC) type.
Square and normal sinusoidal wave forms and wave balancing are illustrated schematically in Figure below.

a. square VS normal sinusoidal wave AC forms b. wave balancing in the AC operating mode 

Electron Emission Improvements of tungsten electrodes in TIG 

The electron emission of tungsten electrodes can be  occasionally enhanced by adding 1-2% thorium  oxide or cerium oxide (or other rare-earth oxides) to the  tungsten.  This  addition  improves  the  current-carrying  capacity of the electrode and consequently there is less chance for contamination of the weld by expulsion of tungsten due to localized electrode overheating and melting, and allows for greater arc stability and easier initiation, As mentioned earlier, both argon and helium are used for shielding with the GTAW process. Argon offers better shielding since it  is heavier and tends to
stay on the work. Arc initiation is also easier, since the binding energy (i.e.work potential) for electrons in the completely filled outermost  electron shell (some of which must  be stripped from this  shell to provide a conducting a plasma) is lower than for helium.

• Miller TIG Welder Models Explained 

The advantage of helium in TIG is a hotter arc, which is the result of the  higher  work potential compared to argon. By using mixtures of these two inert gases, mixed characteristics can be obtained. In summary, the GTAW process is good for welding thin sections due to its inherently low heat input (especially in the DCRP mode), offers better  control of  weld filler dilution by the substrate than many  other processes (again due to low heat input), and is a very clean process (as a result of the excellent protection afforded by inert argon or helium or argon-helium mixtures). Its greatest limitation is its slow deposition rate (only about 1-2 Ibs. or 0.5 1 kg. per hour), although this can be overcome by employing  a  “hot wire” variation in  which the filler  wire is resistance  heated by being  included in the circuit at a lower potential  than the electrode. Deposition rate can also be increased  to compete with GMAW, SMAW, and  FCAW by using much larger,  water-cooled  electrodes with much higher currents (e.g., upward of  a thousand  amperes versus around a  hundred  amperes), or by using a fairly recent variation of the  process that  employs  supplemental flux (fluxed gas- tungsten arc welding). In  both of  these  variations,  the process  must be mechanized, however, to deal with the greater volumes of molten weld metal.

Please Read :

• Aluminothermic or Thermit Welding Principles  
• Submrged Arc Welding 
• Flux shielded metal arc welding process principles 
• Resistance Projection Welding 
• Resistance Spot Welding 
• Resistance Seam Welding 

Read full post »

Aluminothemic Welding or Thermit Welding Principles

Aluminotherrnic welding is commonly known as Thermit welding.  As a subset, these processes use the heat from highly exothermic chemical reactions of solid, particulate materials (or, occasionally, solid particles and a gas) to produce melting and joining, also called coalescence, between metals.  Most often, the reactants employed are oxides with low heats of formation and metallic reducing agents, which when oxidized have high heats of formation, but combinations of two metals or a metal and a non-metal (e.g., H, C, 0, N, B, Si, S, or Se) that will react exothermically to produce a compound with a high heat of formation  can  also be used. The excess heat of formation of the reaction products, in  either case, provides  the energy to produce the weld. As an example, if finely divided aluminum and metal oxides of, say, iron or copper are blended and ignited by means of an external  heat  source,  the aluminothermic reaction (after which the entire group is named) will proceed according to the following general reaction: 

Aluminotherrnlc Welding or Thermit Welding General Reactions and Principles 

Metal oxide + aluminum = aluminum oxide + metal + heat

The reaction is so exothermic that the heat liberated results in the metal formed as a reaction product being liquid. The most common Thermit reactions used to produce welds are – 

By causing the reaction to take place such that this molten metal product can  reach and fill a joint,  a weld can be  made. In Thermit welding as it is usually practiced, the reaction is made to take place in a vessel located above a mold around the aligned and abutted joint elements. Once the reaction takes place, the  molten metal product, being denser than the solid AI,O, product, pours down into the mold under the influence of gravity and casts into the joint to create a weld. To help the reaction proceed, especially for large volumes of reactant and large welds to be made, the mold is often preheated. A typical arrangement for Thermit welding is shown schematically in Figure where concrete reinforcing steel bar is being welded in either a horizontal or vertical orientation.  This  and  the  joining of steel railroad  rails and heavy copper electric cables or buss bars to terminal connectors are common applications of this process. 

Maximum Temperature of Thermit Reactions 

While the theoretical maximum temperature that results from such reactions can be calculated from the  reaction  thermodynamics,  the actual maximum temperature achieved is less precise because the reaction does not take place adiabatically.  In the case of most common reaction maximum theoretical  temperature is approximately 3200°C (5800°F). Even though  the  actual maximum temperature  probably  ranges between 2200°C (4000°F) and 2400°C (4350°F) due to various losses, there is more than enough superheat in the molten metal product to cause melting of the surfaces of the abutting joint elements, thereby producing a real weld. 

More recently, as the result of work by Merzhanov et al. (1972) in Russia, a host of  exothermic reactions have been studied  and used to accomplish surface welding or overlaying by causing the reaction to take place in reactant packed on the surface, and cladding by causing the reaction to take place in reactant sandwiched between layers. Reactions to produce refractory oxides, carbides, nitrides, carbonitrides, borides, silicides, and other non-oxide ceramics as well as intermetallics (e.g., aluminides) have been studied (Hlavacek, 1991) and offer potential to join ceramics to one another and to metals. The former processes are generically classified by the AWS as exothermic welding processes, while the  latter are classified as exothermic brazing processes, the difference being whether any melting of the  substrate(s) occurs, as it must to be considered welding. Alternative names for  these  processes, because of the  propagating and simultaneous  modes in  which the process can take place are: self-propagating high-temperature synthesis (SHS)  and combustion synthesis (CS) 

Please Read : 

• TIG welding Basics 
• Advantages of TIG welding 
• TIG Aluminum Welding 
• MIG Welding Principles 
• Submrged Arc Welding 
• Flux shielded metal arc welding process principles 
• Resistance Projection Welding 
• Resistance Spot Welding 
• Resistance Seam Welding 
• Different types of welding defects

Read full post »

Miller TIG Welder - Dynasty Series Review and Classification

Miller Welders are one of the most famous manufacturers of TIG welding equipment. Performing TIG welding perfectly is an art. And for a clean, successful and accurate TIG weld we need efficient welders and efficient welding machine. Miller TIG welder always comes handy in achieving the desired weld. Miller manufactures two types TIG of welding equipment

1. AC/DC all type metal welder (including aluminum).
2. DC Steel alloy welder. 

The first type includes three different Miller TIG welder which includes 

• Dynasty Series
• Diversion Series and 
• Syncrowave Series 

The second type have only one series named - Maxstar Series . In this article I will talk about the Dynasty series and its classification.

Please Read :

• Miller Bobcat 250 EFI welder/generator review 
• Different Miller TIG Welder Models 

Miller TIG Welder - Dynasty Series Types 

Miller Dynasty welders have the advanced technology which makes it flexible for AC/DC. stick or TIG solutions. It has the inverter technology. 

Features 

• Compact and mobile design producing ease of opearion. 
• Superior weld quality and arc performance.
• Low cost of installation and maintenance .  

Dynasty Models 

Dynasty 200 

• Portable only 45 lb 
• Input voltage - 120-460 Volts 

Applications of Miller Dynasty 200 

1. Fabrication
2. Aerospace
3. Can be used in Food and beverage company
4. Suitable for petroleum or chemical indsutries
5. Useful for Mechanical Contractors 
6. Repair/ maintenance of different metals 
7. Aluminum product building 

Dynasty 280 

• Input voltage 208-575 volts 
• 3 phase or single phase power 
• Two models - 280 and 280 dx 
• weight 52 lb
• Adjustable shoulder strap 
• Pro-set feature available 

Application 

• Fabrication
• Aerospace
• Anodized aluminum fabrication can be done 
• High precision-fabrication can be done 
• Heavy industry uses 
• Aluminum ship building, repair and maintenance 

Dynasty 350/700

• Programmed memory
• Independent AC current control 
• Input power 208-575 volts 

Application of Dynasty 350 /700 

• Fabrication
• Aerospace
• Anodized aluminum fabrication can be done 
• High precision-fabrication can be done 
• Heavy industry uses 
• Aluminum ship building, repair and maintenance 
• Its application includes marine fabrication. 

Dynasty model steel and aluminum welding capability 

Dynasty Quick Specs 

Please Read : 

• TIG welding Basics 
• Advantages of TIG welding 
• TIG Aluminum Welding 
• Submrged Arc Welding 
• Flux shielded metal arc welding process principles 
• Resistance Projection Welding 
• Resistance Spot Welding 
• Resistance Seam Welding 
• Different types of welding defects

Read full post »

Different Miller TIG Welder Models

Welding is an art. There are different types of welding methods. TIG or Tungsten Inert Gas Welding is technique for great welded joints. TIG or Gas Metal Arc Welding (GMAW) needs some great craftsmanship to master. And for this reason we need some decent welding machine from a renowned company. Miller TIG Welder is great when it comes to weld an accurate and clean weld.

Please Read :

• Miller Bobcat 250 EFI welder/generator review 
• TIG welding Basics 
• Advantages of TIG welding 
• TIG Aluminum Welding 

Miller TIG Welder Categories 

Miller Electric provides great TIG welding equipment for avid welder. You and your co-workers will find it great after using some products from Miller Welds. And I also have to mention that the units are very much suitable for the beginners as well as professionals. Miller TIG welder setup is easy, price is reasonable and all the products are durable. They provide mainly two broad classes of welders. 

1. All metals welder including aluminum (AC/DC) which involves 

• Diversion Miller TIG welder series 
• Dynasty series 
• Syncrowave series 

2. Steel Alloys (DC only). It includes 

• Maxstar series 

Diversion Miller TIG welder series

Diversions series is mainly designed for the personal use. Its features include - 

• Low cost
• Ease of setup and 
• A total welding package 
• Great for personal use 

Applications 

• Automobile and motorsports
• Aviation technology  
• 4x4 / Off road 

Dynasty Model Series 

Features 

• Great for Professional use
• Advanced AC/DC TIG welder suitable for all metals. 
• Mobile design 
• Compact and less energy consumption 
• Improved travel moving speed 
• Optimum arc and puddle 

Application

• Great for Fabrication 
• Maintenance and repair 
• manufacturing 

Syncrowave series 

Features 

• Great for light industrial application 
• Suitable for personal use 

Maxstar Series 

Features 

• Advanced TIG technique for steel alloys using DC. 
• Productivity is improved 
• Compact and mobile design. 
• Great ease of arc control 
• Electrical energy savings 

Applications 

• Construction and manufacturing . 
• Fabrication and maintenance. 
• Repair work. 

Please Read: 

• Submrged Arc Welding 
• Flux shielded metal arc welding process principles 
• Resistance Projection Welding 
• Resistance Spot Welding 
• Resistance Seam Welding 
• Different types of welding defects

All Miller TIG welder manual is available. After buying the product they provide great services. So I will suggest to buy Miller products as a mechanical engineer. 

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Miller BOBCAT 250 EFI Engine Drive Welder / Generator Review

Miller BOBCAT 250 EFI Rugged welder / generator is a very good equipment for Stick as well as Flux-Cored Welding. It can be used  for construction and maintenance /repair operations. It is quitter. There is improvement on the sound level. So there is significant improvement in the jobsite communication as a result a safer and more efficient working environment is guaranteed.

Miller bobcat 250 EFI

Miller BOBCAT 250 EFI Engine Drive Welder / Generator Review (907502)

Features : 

1. Less fuel consumption (upto 27 % less)
2. 33 % Less sound. 
3. EFI or Electronic Fuel Injection produces better performance and less operation cost, longer functioning time and less emission than carburetor versions. 
4. Easy maintenance because of new and improved design. Oil can be checked from the front panel. It has single side oil fill and drain system. 
5. 5" shorter and 55 lb lighter than the previous models. Takes less space. 

Review : In this article I am talking about the fuel injection model. The carburetor model is almost the same in operation. This is a great machine for portable welding and even for hobby welding. It is a commercial level thing. It is a multipurpose welder. It can run as a power source for constant current and constant voltage application . Stick, MIG, TIG, Flux cored anything can be used. TIG torch can be attached very easily to the welding lead. It does have a switch right on the front side which gives you TIG, Stick. It also has AC and you can run your 6011 easily on the AC. Both 225 and 250 and EFI all come with the AC mode. It also has a wire positive and negative line. Flux cored or wire both can be used. And all those things can be controlled from one machine. It has a nob for selecting the current range (40 - 130 amp). And then there is the nob to fine tune the current again. Miller has a great job! On the front side there are some flaps. Underneath them you will find connection for your work and electrode. It has 220 output with a 50 amp breaker on it. It has four sockets for regular 120 Volts. Plasma cutters can be added to this. So this is a full functioning completely portable welding machine from this one power source!  It got a little table on the front underneath the door which work as a reference or cheat-sheet for the newbies. On the top Electronic Fuel Injection module cycle. When it is turned on the lights on the top is on which is metering device or fuel gauge. The light will go off if you have any problem. Fuel injection module has start, run/idle and run options. After run option is applied it shows the hours that are remaining for the next fuel change. Once the oil is changed you can reset the module. On the carburetor versions their is a chock nob instead of this EFI module.  On the bottom there is the induction fan for air intake which is actually blown out of the top.  The exhaust line is a short one but it is very quiet. There is a fuel meter on the side. The fuel tank should not full to the brim for some reason. But it actually gives a great run time. The finish is really awesome. The main engine opening door is quiet easy to open. There is a top door for checking the air cleaner, oil filter and oil level indicator. On the back there is the battery. It is cheaper than the Lincoln welders and it has EFI so you will definitely save $500 if you buy this ! It produces 12000 Watts power. When You want to have highest generating power make sure that the fine adjustment nob is set to 10. You will have the ability to weld and run the generator at the exact same time.
Some notes on EFI :    EFI gives the super ease of starting (Really awesome !!). When not welding no fuel is wasted. When welding starts the EFI automatically starts functioning. It saves a lot of power. See the video below it will understand it ! 

Miller BOBCAT 250 EFI Engine Drive Welder Improvements 

• The engine is rotated towards the front side for getting adequate air flow efficiently. 
• Quitter operation is possible. As a result of this improvement the system can be started early, can be functioning all day long without polluting the sound. 
• Can be used for structural construction work, repair, maintenance and fabrication purpose with great ease. 
• Supports Stick Welding SMAW, Flux Cored (FCAW), GMAW or MIG, TIG or GTAW (DC or Non - Critical AC), Air Carbon Arc (CAC-A), Cutting and Gouging (Model 250 only, 3/16 carbons) , Air Plasma Cutting etc. 
• Can be used in extreme conditions. Heavy internal leads are available for durability. 
• Great cooling technology is present for max. performance. 
• Super tough armor is attached for the safety of the welder and prevents accidents. 
• It is heavy duty and versatile.

Bobcat Specs 

Miller BOBCAT 250 EFI Engine Driven Welder Questions and Answers 

• Whats the Miller Bobcat 250 Weight ? ans : 501 lbs 
• How Bobcat 250 is powered ? Diesel / Gasoline ? ans : Gasoline 
• What kind of motor is used in Miller BOBCAT 250 EFI ? ans : 23 HP Kohler . 
• Does bobcat 250 has any cons ? Ans : It needs to be bundled with some more  specific welding kits. 
• What is the price of Miller bobcat 250 EFI ? ans : $4,000.00 - $4,495.00 

Please Read about

Welding :

• TIG welding 
• MIG welding 
• TIG Aluminum Welding 
• TIG Welding Basics 
• Submrged Arc Welding 
• Flux shielded metal arc welding process principles 
• Resistance Projection Welding 
• Resistance Spot Welding 
• Resistance Seam Welding 
• Different types of welding defects. 
• Different Types of Welding Electrodes 

Read full post »

TIG Welding Basics

The History of TIG Welding 

Russel Meredith applied for a patent for TIG or GTAW in 1941. He is most credible for the invention of TIG welding. The main application of TIG or GTAW is found in effective welding of light aircraft. MIG welding of GMAW was invented before TIG welding but light aircrfat welding needed more reliable welding as well as more fusion power and TIG welding is very appropriate for this purpose.  

Actually What is TIG Welding ? 

Tungsten Inert Gas (TIG) Welding is also known as Gas Tungsten Arc Welding (GTAW). 
TIG welding or GTAW is a arc welding process which uses non-consumable electrodes which is actually a tungsten stick. This welding process also needs a filler metal. This process is conducted under the shield of an inert gas which can be helium of argon gas. 

Read More about Different Types of Welding: 

• TIG welding 
• MIG welding 
• TIG Aluminum Welding 
• Submrged Arc Welding 
• Flux shielded metal arc welding process principles 
• Resistance Projection Welding 
• Resistance Spot Welding 
• Resistance Seam Welding 
• Different types of welding defects. 

TIG Welding Basics 

How to TIG (GTAW) weld?

It is the most complex welding process. Like every other welding process TIG needs to keep a certain distance between electrode and job. Both hands are needed to be used in this process. But in GMAW the welder only needs to use only one hand. To strike the arc, high frequency generator is used to create the spark. Generally the spark needs 1.3-3.0 mm from the parent material. There is a alternative to the high frequency arc generation which is the scratch start method. This method posses some demerits. One of them is contamination of the workpiece or job. When a solid arc is present and the distance between the electrode and parent metal is good, the welder have to circle the electrode gently to cause a weld pool to form and filler metal should be added at this time. The welding torch should be kept at an angle about 15 degrees with the metal. Filler material should be added manually and the weld pool should be moved at a constant rate. Please have a look at the video. 

GMAW VS GTAW

What are the benefites of Gas Tungsten Arc Welding (GTAW) over Gas Metal Arc Welding (GMAW)? 

• TIG Welding is much more clean then MIG welding. 
• TIG fuses better than MIG. 
• Accurate Welding with very small tolerances can be done. 
• Aeronautical industry uses this method very frequently. 
• TIG can be  used in Aluminum Welding 

It is also to be mentioned that TIG welding is a slower process than MIG welding. But TIG is better in respect of accuracy. 

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Types Welding Electrodes explained – Non consumable-Consumable electrodes

The piece of wire or rod used to carry current for welding is known as an electrode or welding electrode. It may or may not have flux covering. The electrode produces arc at one end and other end is gripped by a electrode holder. In this article we will discuss the classification of welding electrode as well as explain different welding electrodes types.

Please read about:

• Different types of welding defects 
• TIG welding 
• MIG welding 
• TIG Aluminum Welding 
• Submrged Arc Welding 
• Flux shielded metal arc welding process principles 

Types of Welding Electrodes explained  

For having a clear knowledge about different electrodes I would advisable to have a look at the above mentioned images.
Welding electrode is mainly classified into two broad categories
1. Non-consumable electrodes and
2. Consumable electrodes

Non-consumable or Refractory Electrodes  

Non-consumable electrodes are those which do not melt away or consumed during the welding process. These electrodes involves the use of high melting point materials such as carbon - MP 6700 degree Fahrenheit, pure tungsten MP 6150 degree Fahrenheit, or alloy tungsten. 

Main features of non-consumable welding electrode 

• While welding with these electrodes a filler metal is needed to fill up the gap between the two metal parts. 
• These are used in carbon arc welding and Tungsten Inert Gas (TIG) welding .  
• Tungsten electrodes are much costlier than carbon or graphite electrodes. Tungsten alloy electrodes are costlier. 

Consumable Electrodes 

This electrodes are low melting point electrodes. When electrode and job is struck the arc starts to melt the end of the electrode. The molten electrode is transferred to the job in the form of metal droplets.  

Main features of Consumable welding electrode

• these are more thermally efficient than non consumable electrodes. 
• They are made of different materials depending upon the need and the chemical composition of metals to be joined. 
• These are used in MIG welding in the form of bare electrode. 
• Most commonly used core material is mild steel, low alloy steel and nickel steel. 

  Consumable electrodes can be classified in the following groups

1. Bare electrodes: They don't have any flux coating only the alloy or the metal wire.
2. Light coated electrodes: These are electrodes having coating factor of 1.25 . coating factor = diameter of the electrode / diameter of the core wire .
example : Citobest electrode from AO or Advani Oerlikon.
3. Medium coated electrodes: These have coating factor of about 1.45 .
example : Overcord
4. Heavily coated electrode : Coating factor is between 1.6 and 2.2 . example : citofine .

Covered electrodes can be classified as follows :

• electrodes having cellulose 
• Rutile (titania)
• Electrode having iron oxide 
• Electrode with iron powder 
• Low hydrogen electrode   

Welding Electrode Explained in details 

• Need of filler metal 

Depending upon the material of the electrode, it may melt and supply filler metal; if it is non-consumable, a separate filler metal addition becomes necessary. 

• Core Wire composition 

The core wire is prepared by keeping in mind the type of metal to be welded. The composition of core wire is different for each metal. When mild steel is needed to be welded the core wire must have have similar composition to get a homogeneous weld joint. 

• The size and length of the welding electrode 

The size (diameter) of the electrode core wire totally depends on the amount of metal deposition needed and the type of gap between the two metal plates to be joined. The length of the core depends of the electrical resistance, rigidity and diameter of the electrode. Typical coated electrode dimensions are 150 to 460 mm (6 to 18 in.) in length and 1.5 to 8 mm (j to in.) in diameter. As the thickness of the sections to be welded decreases, the required current and electrode diameter also decrease.

• Current Requirements 

If bigger diameter welding electrodes are used then the requirement of the current will also be higher.

• Specification of the welding electrodes 

Specifications for electrodes and for filler metals, including dimensional tolerances, quality control procedures, and processes, are stated by the American Welding Society (AWS) and the American National Standards Institute (ANSI); some appear in the Aerospace Materials Specifications (AMS) by the Society of Automotive Engineers (SAE).

• Welding electrode numbering system 

Electrodes are identified by numbers and letters (Table 27.2), or by color code, particularly if they are too small to imprint with identification.

 

 Among other requirements, the specifications state that

(a) the wire diameter must not vary more than 0.05 mm (0.002 in.) from nominal size, and
(b) the coatings must be concentric with the wire.


Welding Electrode is sold by weight and are available in a wide variety of sizes and specifications. Selection and recommendations for electrodes for a particular metal and its application can be found in supplier literature and in the various handbooks

• Electrode coating 

Claylike materials are used to coat the electrodes. These materials include silicate binder as well as powdered materials such as various oxides, metal alloys, fluorides and carbonates and cellulose. Cellulose includes cotton cellulose and wood flour. 

Brittle electrode coatings has some functions and they take part in complex interactions at the time of welding. The basic functions are 

a) they help in stabilizing the arc. 

b) Act as shield against the surrounding environment by producing gases. The gases produced are mainly carbon dioxide CO2 and water vapor and small amounts of carbon monoxide CO and Hydrogen. 

c) They control the rate at which the electrode melts. 

d) Act as a flux and protect the weld joint against the formation of oxides and other inclusions. The resulting slag also protects the molten weld pool. 

e) These coatings add alloying elements in the weld zone and enhances the properties of the weld joint. Deoxidizers help the joint from becoming brittle. 

To ensure a good weld the deposited coating or slag must be removed after each pass. A wire brush can be used for cleaning the deposited coating. 

Bare electrodes are also available which are made of stainless steel of aluminum alloys. 

Please Read :

• Resistance Projection Welding 
• Resistance Spot Welding 
• Resistance Seam Welding 

Read full post »

Advantages of TIG Aluminium Welding

Gas Metal Arc Welding (GMAW) and Gas Tungsten Arc Welding (GTAW) are suitable for aluminum welding. Aluminum alloy castings need the same technique applied to aluminum sheets and many different wrought products. Many castings are vulnerable to thermal strains because of delicate designs and varying cross sectional areas. Sometimes aluminum alloy castings need heat treatments before welding. TIG Aluminum Welding is very much common in welding aluminum castings. But sometimes welding contributes in the destruction of the effect of initial heat treatment. In those cases it is highly recommended to heat treat the metal after welding. In this article we will discuss about the advantages of tig aluminum welding . 

Please read about 

• Tungsten Inert Gas (TIG) Welding and 
• Metal Inert Gas (MIG) Welding  

TIG Aluminum Welding Benefits 

• One of the many advantages of TIG aluminum welding is it eliminates the requirement of flux. As a result the welding is free from a source of corrosion. 
• Welding can be done in any position. TIG welding also gives better visibility and high speed welding can be performed. 
• Pressure tight joints can be got with very low distortion and high strength. 
• GTAW is relatively easy to perform and it is a high speed welding technique. It is one of the reasons that TIG is preferred over other fusion welding methods. 
• TIG welding uses non-consumable electrodes and AC current. Argon or Helium is used as the inert shielding gas. If filler material is needed then it can be fed automatically or manually. 
• Very thin aluminum (0.6 mm 0r 0.025 inches) can be welded but materials having thickness of 1 mm or more give good results. 

I think now you know why tig aluminum welding is used .  

Please Read : 

• Different Welding Defects 
• Pros and Cons of Submerged arc welding 

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Different Types of Welding Defects

In this article we will be -
Identifying common welding defects
Preventing and fixing problems with your welds

If I could wave my magic filler rod and make it so that all your welds would be strong, clean, and sharp-looking, I’d certainly do it. But the last time I went to the welding supply shop and asked to buy a magic filler rod, they looked at me like I was nuts, so for now you just have to live with the fact that some of your welds will be imperfect. Don’t worry about it too much; after all, no welder is perfect, and welding can be a tricky endeavor. What I can do is fill you in on some of the most common weld flaws so that when they show up, you realize that you’re dealing with the same kinds of challenges that hundreds of thousands of welders have cursed and spat about since the first guy figured out how to strike an arc. These are the kinds of defects that you’re likely to notice only after you’ve finished a weld (either a single pass or a complete weld, depending on the defect). Most are prettyeasy to detect, and — thankfully — relatively easy to adjust for and prevent. To help prevent welding defects before they happen, be sure your welding materials are clean and in good shape before you start a project. The metal you’re planning to weld should be free of any material that may contaminate the weld. Remove any grease, paint, or oil from the metal. You should also
put the pieces to be welded in place to make sure they fit together and line up properly.

Please Read :

• Different Types of Casting defects.
• Types of patterns used in casting process. 

 Most Common Types of Welding Defects

 Incomplete Penetration

Incomplete penetration happens when your filler metal and base metal aren’t joined properly, and the result is a gap or a crack of some sort. Check out the Figure below for an example of incomplete penetration.

a common case of incomplete penetration

Welds that suffer from incomplete penetration are weak at best, and they’ll  likely fail if you apply much force to them. (Put simply, welds with incomplete  penetration are basically useless.)
Here’s a list of the most common causes of incomplete penetration welding defect.

The groove you’re welding is too narrow, and the filler metal doesn’t
reach the bottom of the joint.

✓ You’ve left too much space between the pieces you’re welding, so they
don’t melt together on the first pass.
✓ You’re welding a joint with a V-shaped groove and the angle of the
groove is too small (less than 60 to 70 degrees), such that you can’t
manipulate your electrode at the bottom of the joint to complete
the weld.
✓ Your electrode is too large for the metals you’re welding.
✓ Your speed of travel(how quickly you move the bead) is too fast, so
not enough metal is deposited in the joint.
✓ Your welding amperage is too low.If you don’t have enough electricity
going to the electrode, the current won’t be strong enough to melt the
metal properly

 Incomplete Fusion

Incomplete fusion occurs when individual weld beads don’t fuse together, or  when the weld beads don’t fuse properly to the base metal you’re welding,  such as in below.

a textbook example of incomplete fusion

The most common type of incomplete fusion is called overlap and usually  occurs at the toe(on the very top or very bottom of the side) of a weld. One of the top causes is an incorrect weld angle, which means you’re probably holding the electrode and/or your filler rods at the wrong angle while you’re making a weld; if you think that’s the case, tweak the angle a little at a time until your overlap problem disappears.

Here are a few more usual suspects when it comes to incomplete fusion
causes.

✓ Your electrode is too small for the thickness of the metal you’re welding.
✓ You’re using the wrong electrode for the material that you’re welding.
✓ Your speed of travel is too fast.
✓ Your arc length is too short.
✓ Your welding amperage is set too low.
If you think your incomplete fusion may be because of a low welding amperage, crank up the machine! But be careful: You really need only
enough amperage to melt the base metal and ensure a good weld.
Anything more is unnecessary and can be dangerous.
✓ Contaminants or impurities on the surface of the parent metal(the metal
you’re welding) prevent the molten metal (from the filler rod or elsewhere
on the parent metal) from fusing.

Undercutting

Undercutting is an extremely common welding defect. It happens when your  base metal is burned away at one of the toes of a weld. To see what I mean, look at Figure.

When you weld more than one pass on a joint, undercutting can occur between the passes because the molten weld is already hot and takes less heat to fill, yet you’re using the same heat as if it were cold. It’s actually a very serious defect that can ruin the quality of a weld, especially when more than 1⁄32 inch is burned away. If you do a pass and notice some undercutting, you must remove it before you make your next pass or you risk trapping slag (waste material — see the following section) into the welded joint (which is bad news). The only good thing about undercutting is that it’s extremely easy to spot after you know what you’re looking for.

Here are a few common causes of undercutting:
✓ Your electrode is too large for the base metal you’re welding.
✓ Your arc is too long.
✓ You have your amperage set too high.
✓ You’re moving your electrode around too much while you’re welding.
Weaving your electrode back and forth is okay and even beneficial, but if
you do it too much, you’re buying a one-way ticket to Undercutting City
(which is of course the county seat for Lousy Weld County).

Slag Inclusions

A little bit of slag goes a long way . . . toward ruining an otherwise quality weld. Slagis the waste material created when you’re welding, and bits of this solid material can become incorporated (accidentally) into your weld, as in Figure . Bits of flux, rust, and even tungsten can be counted as slag and can cause contamination in your welds.

Common causes of slag inclusions include

✓ Flux from the stick welding electrode that comes off and ends up in the
weld
✓ Failure to clean a welding pass before applying the next pass
Be sure to clean your welds before you go back in and apply a second weld bead.
✓ Slag running ahead of your weld puddle when you’re welding a V-shaped
groove that’s too tight
✓ Incorrect welding angle
✓ Welding amperage that’s too low

Flux Inclusions

If you’re soldering or brazing (also called braze welding), flux inclusions can be a real problem. If you use too much flux in an effort to “float out” impurities from your weld, you may very well end up with flux inclusions like those in Figure . (Head to Chapter 13 for more on brazing and soldering.)

If you’re working on a multilayer braze weld, flux inclusion can occur when you fail to remove the slag or glass on the surface of the braze before you apply the next layer. When you’re soldering, flux inclusion can be a problem if you’re not using enough heat. These inclusions are usually closely spaced, and they can cause a soldered joint to leak. If you want to avoid flux inclusions (and believe me, you do), make sure you do the following:
✓ Clean your weld joints properly after each pass.This task is especially
important when you’re brazing.
✓ Don’t go overboard with your use of flux.
✓ Make sure you’re using enough heat to melt the filler or flux material.

Porosity

If you read very much of this book, you quickly figure out that porosity(tiny holes in the weld) can be a serious problem in your welds (especially stick or mig welds). Your molten puddle releases gases like hydrogen and carbon dioxide as the puddle cools; if the little pockets of gas don’t reach the surface before the metal solidifies, they become incorporated in the weld, and nothing can weaken a weld joint quite like gas pockets. Take a gander at Figure  for an example of porosity.

Following are a few simple steps you can take to reduce porosity in your
welds:
✓ Make sure all your materials are clean before you begin welding.
✓ Work on proper manipulation of your electrode.
✓ Try using low-hydrogen electrodes.

Cracks

Cracks can occur just about everywhere in a weld: in the weld metal, the plate next to the weld metal, or in any other piece affected by the intense heat of welding. Check out the example of cracking in Figure.

Here are the three major types of cracks, what causes them, and how you can prevent them.

✓ Hot cracks:

This type of crack occurs during welding or shortly after you’ve deposited a weld, and its cause is simple: The metal gets hot too
quickly or cools down too quickly. If you’re having problems with hot cracking, try preheating your material. You can also postheat your material, which means that you apply a little heat here and there after you’ve finished welding in an effort to let the metal cool down more
gradually.

✓ Cold cracks:

This type of crack happens well after a weld is completed and the metal has cooled off. (It can even happen days or weeks after a
weld.) It generally happens only in steel, and it’s caused by deformities in the structure of the steel. You can guard against cold cracking by
increasing the thickness of your first welding pass when starting a new weld. Making sure you’re manipulating your electrode properly, as well as pre- and postheating your metal, can also help thwart cold cracking.

✓ Crater cracks:

These little devils usually occur at the ending point of a weld, when you’ve stopped welding before using up the rest of an
electrode. The really annoying part about crater cracks is that they can cause other cracks, and the cracking can just kind of snowball from
there. You can control the problem by making sure you’re using the appropriate amount of amperage and heat for each project, slowing your
speed of travel, and pre- and postheating.

Warpage

If you don’t properly control the expansion and contraction of the metals you work with, warpage(an unwanted distortion in a piece of metal’s shape) can be the ugly result. Check out an example in Figure.

If you weld a piece of metal over and over, the chances of it warping are much higher. You can also cause a piece of metal to warp if you clamp the joints too tightly. (If you allow the pieces of metal that make the joint to move a little, there’s less stress on them.)
Say you’re welding a Tjoint. The vertical part of the Tsometimes pulls itself toward the weld joint. To account for that movement, simply tilt the vertical part out a little before you weld, so that when it tries to pull toward the weld joint, it pulls itself into a nice 90-degree angle!
The more heat you use, the more likely you are to end up with warpage, so be sure to use only the amount of heat you need. Don’t overdo it. Opting for a slower speed of travel while welding can also help to cut down on warpage.

Spatter

Spatter(small particles of metal that attach themselves to the surface of the material you’re working on.) is a fact of life with most kinds of welding; no matter how hard you try, you’ll never be able to cut it out completely. You can see it in all its glory in Figure 11-5 in Chapter 11.
You can keep spatter to a minimum by spraying with an anti-spatter compound (available at your welding supply store) or by scraping the spatter off the parent metal surface.

These are the 10 most commonly found welding defects. Some new and useful articles are coming soon. So stay tuned.

Read :

• Gas Metal Arc Welding (GMAW) or MIG Welding
• Flux shielded metal arc welding process principle
• Tungsten Inert Gas welding or TIG welding 
• Advantages and Disadvantages of Submerged arc welding
• Submerged Arc Welding Working Principles and Uses
• Resistance Seam Welding (RSEW)
• Resistance Spot Welding 
• TIG Aluminum Welding 

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