Spot welding pdf

Lutz Dorn, Technische Universität, Berlin Objectives: − to describe the spot welding characteristics of aluminium and its alloys, − the spot welding process , − the choice of process parameters, − strength values, − electrode life and − requirements for quality assurance. SPOT WELDING can cause fire or explosion. Sparks can fly off from the welding arc.

The flying sparks, hot workpiece, and hot equipment can cause fires and burns. Accidental contact of elec-trode to metal objects can cause sparks, explosion, overheating, or fire. Check and be sure the area is safe before doing any welding.

More specifically, it tells the electrodes when to close and when to open, and it tells the welding current when to start and when to stop. The welding control may be thought of as the “brains” and the machine as the “muscle” of the overall resistance welding system. Due to the inaccessibility of nugget in inspection process,.

Fin read and cite all the research. The purpose of the Welding Handbook for maritime welders is to provide guidance in modern welding and related processes and to provide the welder with a source of practical information on the right solution to specific onboard welding problems. In electric resistance welding ( ERW ) methods, a high current is passed through the metal pieces to be joined together and the heat is produced due to the resistance in the electric circuit.

Although some other fusion welding methods, such as laser beam welding and gas metal arc welding , as well as non-thermal joining approaches, such as riveting, bolting and adhesive bonding, are being used in automotive manufacturing nowadays, spot welding still remains the most important joining method owing to its low cost and high robustness. Spot welding is one of the type of welding processes. Resistance Spot Weldingis the joining of overlapping pieces of metal by applying pressure and electrical current.

These joints created by resistance spot welding form a “button” or “fused nugget. Resistance spot welds are found typically on flanges, staggered in a single row of consecutive welds. Resistance welding is not recommended for aluminum, copper or copper alloys. Use for steel and stainless steel only.

For more heat (amperage output), use shorter tongs. For units without a heat control, tong length can be used for a control. For instance, for thin metals where you want less heat, longer tongs can be used. Series Welding - RSW which utilizes two electrodes positioned adjacent to each other but separated by an air gap or other dielectric.

Each electrode contacts the same surface of base material. The heat generated creates a plastic state and produces fusion at the interface surfaces. Although Resistance Welding is now over 1years ol the joining of metals by the application of heat and pressure is much older. The goal of good resistance. In general, the highest resistance in.

Therefore, if you’re wondering what the torque specification should be for your weld nut, simply determine the torque capacity of the fastener itself. Oxyfuel gas welding (OFW). These joining processes use an oxyfuel gas, such as a mixture of oxygen and acetylene, to produce a hot flame for melting the base metal and filler metal, if one is used. In spot welding the weld is effected by the heat produced due to resistance to the flow of current through two or more overlapping work pieces held pressed together between the electrodes.

This is the simplest form of resistance welding and does not pose any problem for welding sheets ranging u to 12. What is Spot Welding : It is used for joining two or more sheets of metal.

The sheets to be welded are held overlapping between the two electrodes, one moveable and the other fixed. Heavy current is passed through the electrodes. Pressure is applied from the top electrode by moving it downward. There is no need to use any fluxes or filler metal to create a join by spot welding , and there is no dangerous open flame.

Automated machines can spot weld in factories to speed up production.