8. Welding Processes There are various welding processes used to join different parts of the automobile exhaust system. These include:8.1. High frequency resistance welding8.2. Continuous high frequency resistance welding8.3. Laser welding8.4. Resistant spot welding8.5. Gas tungsten arc welding8.6. Brazing e8.7. Gas metal arc welding (GMAW) with solid or flux-cored wires. These welding processes can be made semi-automatic, mechanized or fully robotic based on various factors. Of all these welding processes, the GMAW process is mainly used to fabricate the exhaust system. Furthermore, the GMAW process using metal-cored stainless steel wires is much simpler and less expensive than solid wires for welding new stainless steel materials used in automobile exhaust system manufacturing. [ ]8.1. Resistance weldingA welding process in which bonding occurs through the heat produced by the workpiece's resistance to the flow of low-voltage, high-density electrical current in a circuit. The workpiece is the circuit part. In resistance welding, pressure is applied constantly so that the electrical circuit can be maintained continuously. This pressure will help the heated parts fuse together. In this process the parts are not melted for joining, but are heated to the plastic state just prior to casting and then forced together for joining. In automotive exhaust welding, continuous welds are usually used to weld one part to another. Therefore, the type of resistance welding process used in automotive exhausts to produce continuous welds is high frequency continuous resistance welding.8.2. High frequency continuous resistance weldingIn this process the welding current is supplied at high frequency (200-500 kHz). This high frequency provides localized heating. So, this… half of the paper… systems are-12.2.1. Arcaloy MC 308L12.2.2. Arcaloy MC 309L12.2.3. Arcaloy MC 316L.A9.2.1. Arcaloy MC308L (AWS A5.9-93, EC 308L): AISI grades of 301, 302, 304, 304L, 308 and 308L are welded from Arcaloy 308L.9.2.2. Arcaloy MC309L (AWS A5.9-93, EC 316L): is used to weld various joints made between carbon steels and various stainless steels.9.2.3. Arcaloy MC316L.A (AWS A5.9-93, EC 316L): This type of austenitic grade is used to weld AISI 316 and 316L stainless steel grades to prevent pitting corrosion. The following table shows the composition of austenitic grades of SSMC wires-Table 9: Composition of austenitic grades of SSMC wires [24] SSMC ferritic and austenitic wires of the Arcaloy family are generally packaged in spools of 15 Kg, 20 Kg and also in bundles 227kg marathon but these 227kg marathon packs are usually preferred by exhaust system manufacturers.