Seven major auto parts processing technology (4）

4. About welding

Welding is a process in which two pieces of metal are joined together by local heating or simultaneous heating and pressure.

We common workers with a mask in one hand, the other hand holding the wire connected with the welding pliers and welding rod welding method is called manual arc welding, which is the use of high temperature arc discharge to melt the electrode and welding parts, so that the joint.

Manual arc welding is seldom used in automobile manufacturing.Spot welding is the most widely used in the manufacture of automobile body.Spot welding is suitable for welding thin steel plates by applying pressure to two electrodes to bond the plates together and by heating and melting the joints (circular as of the FAQ 5 -- 6 diameter) with an electric current to secure the joints.When welding 2 body parts, the edges are welded one point at 50-100 FAQ to form discontinuous multi-point connections between the 2 parts.It usually takes thousands of solder spots to weld an entire car body.The strength of the solder joint is very high, each solder joint can withstand the tension of 5kN, even the steel plate is torn, but still can not separate the solder joint parts.

The common gas welding in the repair workshop is to use acetylene combustion and oxygen combustion to produce a high temperature flame, so that the welding rod and welding parts melting and joint method.This high temperature flame can also be used to cut the metal, known as gas cutting.The application of gas welding and gas cutting is more flexible, but the heat affected zone of gas welding is larger, which causes the deformation and metallographic structure change of the weldment, and reduces the performance.Therefore, gas welding is rarely used in automobile manufacturing.