Stainless steel welded pipe is a steel pipe made of steel or steel strip after being crimped and formed by a unit and a mold. The production process is simple and the production efficiency is high. At present, the welding methods of stainless steel welded pipes used in industry mainly include argon arc welding, high frequency welding, plasma welding and laser welding. Several welding methods have their own characteristics, and argon arc welding and high-frequency welding are currently used more. The following is a detailed introduction to several types of welding technology.
Stainless steel welded pipes require deep penetration, no oxide inclusions, and as small a heat affected zone as possible. Tungsten inert gas shielded argon arc welding has good adaptability, high welding quality and good penetration performance. Its products are used in chemical industry, It is widely used in nuclear industry and food industry.
The disadvantage of argon arc welding is that the welding speed is not high. In order to improve the welding speed, argon arc welding with three-electrode welding torch is generally used. Quality has also improved. The combination of argon arc welding and plasma welding can weld steel pipes with larger wall thickness. In addition, 5-10% hydrogen in argon gas, and then high-frequency pulse welding power source can also increase the welding speed.
High frequency welding
High-frequency welding has a higher power supply, and can achieve a higher welding speed for steel pipes of different materials and outer diameters and wall thicknesses. Compared with argon arc welding, it is more than 10 times its higher welding speed. Therefore, the production of general-purpose stainless steel pipes has a high production rate.
Due to the high speed of high-frequency welding, it is difficult to remove the burrs in the welded steel tube. At present, high-frequency welded stainless steel pipes cannot be accepted by the chemical and nuclear industries, which is one of the reasons. In terms of welding materials, high-frequency welding can weld various types of austenitic stainless steel pipes. At the same time, the development of new steel grades and the progress of forming welding methods have also successfully welded steel grades such as ferritic stainless steel AISI409.
Combined welding technology
Combination welding methods include: argon arc welding + plasma welding, high frequency welding + plasma welding, high frequency preheating + three-electrode torch argon arc welding, high frequency preheating + plasma plus argon arc welding.
Combination welding increases the welding speed very significantly. The welding seam quality of the combination welded steel pipe using high frequency preheating is comparable to that of conventional argon arc welding and plasma welding. The actual welding operation is simple and clear, and the entire welding system is easy to realize automation. This combination is easy to connect with existing high frequency welding equipment. , the investment cost is low, and the benefit is good.
Various welding methods of stainless steel welded pipes have their own advantages and disadvantages. How to make use of strengths and avoid weaknesses, combine several welding methods to form a new welding process, and meet people's requirements for stainless steel welded pipe quality and production efficiency, is a new trend in the current development of stainless steel welded pipe technology.
Tips: the production process of seamless steel pipe can be divided into two types: cold-drawing and hot-rolling. The production process of cold-rolled seamless steel pipe is generally more complicated than that of hot-rolling, but the accuracy of cold-rolled seamless pipe specification is higher than that of hot-rolling, and the surface It looks brighter than the thick-walled seamless steel pipe, the surface is not too rough, and the caliber does not have too many burrs.