High frequency welded pipe machine is widely used in the production of stainless steel welded pipes for large-scale power station generator sets. Most of the production of stainless steel welded pipes in my country is the introduction or use of advanced foreign equipment and technology.

Heat treatment is an important process to ensure the performance of stainless steel welded pipes. One of its purposes is to eliminate the residual stress generated during the cold working process of coiling the stainless steel strip into a tube and the welding process. The second purpose is to perform solution treatment to make the welded steel pipe The carbides produced at this time are all solid-dissolved into austenite, and then quickly cooled down to prevent the austenite from precipitation or phase change during the cooling process. At present, continuous roller hearth furnaces are generally used in the heat treatment of stainless steel pipes using high frequency welded pipe machine in my country. Since no protective atmosphere is used, and producer gas is used as fuel, then pickling is used to remove the heat generated on the surface of the steel pipe after heat treatment. Oxide skin corrodes the steel pipe surface and causes environmental pollution. Some developed countries have now widely used online bright heat treatment technology. Since it can eliminate the traditional off-line heat treatment and pickling process, it has the advantages of increasing productivity and reducing labor intensity. Therefore, my country should vigorously promote the production of stainless steel welded pipes with protective atmosphere control. System development of bright heat treatment technology. The author analyzed some of the problems that occurred during the on-line bright heat treatment of the welded pipe production line introduced in my country, in order to improve the product quality and yield rate.

The factors that affect online bright heat treatment can be divided into six kinds.We introduce the influence of cooling temperature and the influence of welded pipe surface.

③The influence of cooling temperature

After the stainless steel welded pipe is heated to 1050 ～ 1150 ℃, the welded pipe should be quickly cooled down. On the one hand, it is ensured that the austenite does not precipitate during the cooling process. On the other hand, the temperature of the pipe will be Should be reduced to a temperature that does not oxidize. Therefore, the cooling temperature is very important, and the temperature range must be strictly controlled.

④The influence of welded pipe surface

The state of the surface of the stainless steel welded pipe before entering the furnace has a great influence on the bright heat treatment. If the surface of the welded pipe has moisture, grease and other dirt attached to the furnace, a light green oxide color will appear on the surface of the welded pipe after the bright heat treatment. Therefore, before entering the heat treatment furnace, the surface of the stainless steel welded pipe must be very clean, and no moisture is allowed on the surface of the welded pipe. If necessary, it can be dried in a dryer before entering the furnace.

The main factors affecting the on-line bright heat treatment of stainless steel welded pipe made by high frequency welded pipe machine are the influence of heat treatment temperature. ②The influence of protective gas. ③The influence of cooling temperature. ④The influence of welded pipe surface. ⑤The influence of heat treatment furnace sealing. ⑥The influence of other factors on bright heat treatment.