Technical Classification Of Stainless Steel Welded Pipes

Stainless steel is a low-cost, corrosion-resistant material with a perfect surface finish that also offers excellent strength. Stainless steel welded pipes are designed for industrial purposes such as petroleum, chemicals, medicine, and food. Today, we are going to talk about technical classification of stainless steel welded pipes.

1. Argon arc welding technology

Stainless steel welded pipes require deep penetration, no oxide inclusions, and a heat-affected zone as small as possible. TIG welding with tungsten inert gas protection has good adaptability, high welding quality, and good penetration performance. Its products are widely used in chemical and nuclear industries. Widely used in industrial and food industries. The welding speed is not high, which is a shortcoming of argon arc welding. In order to increase the welding speed, a three-pole welding gun is generally used for welding. The wall thickness of the welded steel pipe is S≥2mm. The welding speed is 3-4 times higher than that of a single welding gun, and the quality is also improved. TIG welding and plasma welding can weld steel pipes with larger wall thicknesses. In addition, adding 5-10% hydrogen to the argon gas and then using a high-frequency pulse welding power source can also increase the welding speed.

2. High frequency welding technology

High-frequency welding has higher power and can achieve higher welding speeds for steel pipes of different materials and outer diameters. Compared with argon arc welding, the maximum welding speed is increased by more than 10 times. Therefore, the production of general stainless steel pipes has higher productivity. Due to the high speed of high-frequency welding, it is difficult to remove burrs from pipes. At present, high-frequency welded stainless steel pipes are not acceptable for the chemical and nuclear industries. This is one of the reasons. In terms of welding materials, high-frequency welding can weld various austenitic stainless steel pipes. At the same time, the development of new steel types and the advancement of form welding methods have also successfully welded ferritic stainless steel AISI409 and other steel types.

3. Combination welding technology

Combination welding methods include: argon arc welding plus plasma welding, high frequency welding plus plasma welding, high frequency preheating plus three-gun argon arc welding, and high frequency preheating plus plasma argon welding. Combination welding can significantly increase the welding speed. The weld quality of steel pipes welded by high-frequency preheating combination is the same as that of traditional argon arc welding and plasma welding. The welding operation is simple and the entire welding system is easy to automate. This combination is easy to cooperate with existing high-frequency welding equipment. Good performance, low investment cost and good benefits. Each welding method of stainless steel welded pipe has its advantages and disadvantages.