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This is another type of butt welding, the difference consisting in the method of heating the base metals. The electrodes are clamped to the parts to be joined, and a heavy current is passed through them. The movable electrode brings the surface of the metal it holds into contact with the surface of the metal held in the stationary electrode. Just before the two pieces meet, an arc developed in the short gap causes sufficient heat to make the surface to be joined plastic.

• This is another type of butt welding, the difference consisting in the method of heating the base metals. The electrodes are clamped to the parts to be joined, and a heavy current is passed through them. The movable electrode brings the surface of the metal it holds into contact with the surface of the metal held in the stationary electrode. Just before the two pieces meet, an arc developed in the short gap causes sufficient heat to make the surface to be joined plastic.

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This process is similar to flash welding inasmuch as it relies upon a sudden discharge of electrical energy (produced by the arc) at the joint to generate sufficient heat to make the surfaces to be joined plastic. The pressure required to accomplish the weld at the proper moment is obtained by employing a heavy spring.

• This process is similar to flash welding inasmuch as it relies upon a sudden discharge of electrical energy (produced by the arc) at the joint to generate sufficient heat to make the surfaces to be joined plastic. The pressure required to accomplish the weld at the proper moment is obtained by employing a heavy spring.

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This a resistance-welding process which consists of passing two or more base metals between electrodes which are in the form of rollers. The current is transmitted through the electrodes to the metals. The mechanical pressure required for forcing them together, as well as the current is transmitted by the roller-shaped electrodes. The welded joint thus produced is similar to a seam made in cloth.

• This a resistance-welding process which consists of passing two or more base metals between electrodes which are in the form of rollers. The current is transmitted through the electrodes to the metals. The mechanical pressure required for forcing them together, as well as the current is transmitted by the roller-shaped electrodes. The welded joint thus produced is similar to a seam made in cloth.

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Resistance – welding process

• Resistance – welding process

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This process is similar to spot welding and consists of joining two pieces of metal, one or both of which have mechanically formed projections. The purpose of the projection is to localize the current.

• This process is similar to spot welding and consists of joining two pieces of metal, one or both of which have mechanically formed projections. The purpose of the projection is to localize the current.

• The current and pressures required for this type of welding are heavier than those applied in spot welding. Various sheet-metal parts used in automobile and aircraft production are welded by this process.

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Spot\ Projection Pneumatic Welding machine

• Spot\ Projection Pneumatic Welding machine

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This is a fusion-welding process in which surfaces to be joined are fused by the heat of an electric arc. By bringing the work and the electrode together as conductors, an electric circuit is established; then, by separating the conductors, an electric arc is created in which the electrical energy is converted into heat.

• This is a fusion-welding process in which surfaces to be joined are fused by the heat of an electric arc. By bringing the work and the electrode together as conductors, an electric circuit is established; then, by separating the conductors, an electric arc is created in which the electrical energy is converted into heat.

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In gas welding, the fusion heat (which is very high) is supplied by combining suitable gases. All gas welding process utilize oxygen combined with acetylene and other fuels. The welding torch or blowpipe consists essentially of a gas mixing chamber and usually is designed in two types: the low-pressure injection type9 and the equal-pressure type.

• In gas welding, the fusion heat (which is very high) is supplied by combining suitable gases. All gas welding process utilize oxygen combined with acetylene and other fuels. The welding torch or blowpipe consists essentially of a gas mixing chamber and usually is designed in two types: the low-pressure injection type9 and the equal-pressure type.

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1.Welding

• 1.Welding

• 2. Forge or Blacksmith welding

• 3. Thermit Welding

• 4. Electric welding

• 5. Types of resistance welding:

• -spot welding;

• - butt welding;

• -flash welding;

• - percussion welding

• -seam welding;

• -projection welding;

• - Electric Arc Welding

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Forge or Blacksmith welding

• Forge or Blacksmith welding

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Thermit Welding

• Thermit Welding

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The temperature of the molten metal is high enough to fuse the broken sections, thus forming a homogeneous mass of metal. The equipment for thermit welding is simple and inexpensive but the quality of the weld is not such as to recommend it for extensive use. The process can be used only on low carbon steels and wrought iron.

• The temperature of the molten metal is high enough to fuse the broken sections, thus forming a homogeneous mass of metal. The equipment for thermit welding is simple and inexpensive but the quality of the weld is not such as to recommend it for extensive use. The process can be used only on low carbon steels and wrought iron.

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This type of welding is a pressure process, as is forge welding. It consists of heating to their plastic temperature the surfaces of parts to be joined, then applying pressure mechanically to achieve complete union of the parts. The heating is accomplished by passage of a heavy, localized electric current. Alternating current of common commercial voltage is employed for this purpose. In all types of resistance welding, selection of proper electrodes is important to the success of the process. Electrodes must possess a high degree of thermal and electrical conductivity and they also must possess strength and hardness.

• This type of welding is a pressure process, as is forge welding. It consists of heating to their plastic temperature the surfaces of parts to be joined, then applying pressure mechanically to achieve complete union of the parts. The heating is accomplished by passage of a heavy, localized electric current. Alternating current of common commercial voltage is employed for this purpose. In all types of resistance welding, selection of proper electrodes is important to the success of the process. Electrodes must possess a high degree of thermal and electrical conductivity and they also must possess strength and hardness.

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Types of resistance welding are: spot welding; butt welding; flash welding; percussion welding; seam welding; projection welding.

• Types of resistance welding are: spot welding; butt welding; flash welding; percussion welding; seam welding; projection welding.

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By this process the parts to be welded are gripped mechanically and pressed together while heat is generated by passage of a heavy current through the area of the joint.

• By this process the parts to be welded are gripped mechanically and pressed together while heat is generated by passage of a heavy current through the area of the joint.

• Butt welding is used extensively for resistance welding work. Pipes, tubing, bars, rods, light-and medium-weight structural shapes, etc, may be butt welded.