With the continuous progress of the material processing technology, the stainless steel pipe has also ushered in a new development opportunity. Typical applications such as automobile exhaust pipe, fuel pipe, injection nozzle and other automobile components.
In the production of stainless steel pipes, a flat stainless steel belt is first formed and then rolled into a circular pipe. After forming, the joint of the stainless steel pipe is required to be welded. Because the weld will affect the formability of the final parts, it is necessary to choose the suitable welding technology if the strict test standard is to be reached. Tungsten arc gas shielded arc welding, high frequency induction welding and laser welding have been widely used in the welding of stainless steel pipes.
High frequency induction welding
In high frequency contact welding and high frequency induction welding, the power supply equipment and the pressure supply equipment are independent. In addition, two methods can be used in the bar, is a soft magnetic element is placed in the interior of the body, which helps in the stainless steel band edge welding flow convergence.
In the two case, stainless steel strip was cut and cleaned up, will be rolled up, then sent to the welding point. In addition, the cooling agent is used for cooling the induction coil used during the heating process. Then, a part of the coolant will be used in the extrusion process. In this respect, there is a great force on the pulley, which prevents the formation of porosity in the welding area. But more pressure can be used to increase the burr. So the specially designed cutters can be used to remove the burrs inside and outside the stainless steel pipe.
Tungsten arc welding arc welding
Traditionally, the stainless steel pipe production plant will choose tungsten electrode to protect the arc welding process. This process forms a welding arc between two non expendable tungsten electrodes. And into the inert gases from the gun guided, plasma can shield electrode, forming an ionized stream, and protect the molten weld pool. This process can effectively repeat the high quality welding process.
The advantage of this process is repeated, welding process will not splash, you can also remove the porous. This is a process of electrical conduction, so the process is slow.
In all stainless steel pipe welding applications, the edge of the stainless steel band will be melted. When the clamping bracket is used to squeeze the edge of the steel pipe together, the edge of the stainless steel belt will solidify. But for laser welding, it is characterized by its high energy beam density. The laser beam not only melts the surface of the stainless steel material, but also forms a spoon hole, which leads to the very narrow appearance of the weld in the stainless steel pipe.
When the power density of laser welding is less than 1MW/cm2, it will not form enough energy density to produce a spoon hole. In this way, the process obtained without a keyhole is wide and shallow. The high precision of the laser welding is higher, which reduces the grain growth and helps to improve the metallographic quality of the stainless steel.
Source: China Stainless Steel Pipes Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)