Views: 0 Author: Site Editor Publish Time: 2016-09-06 Origin: Site
Stainless steel tube heat treatment abroad widely used continuous heat treatment furnace with protective gas without oxidation, the intermediate heat treatment in the process of production and the final finished heat treatment, because of lack of oxidation of the surface of the light can get, and cancel the traditional pickling process.The adoption of the heat treatment process is to improve the quality of the steel tube, and overcome the pickling pollution to the environment.
According to the current trend of world development, basic light continuous furnace is divided into three types:
(1) the roller bottom type bright heat treatment furnace.This type furnace is suitable for large size, large quantities of steel tube heat treatment, hour yield of 1.0 tons.Can use the protective gas for high purity hydrogen, ammonia and other protective gas.Can be equipped with convection cooling system, in order to rapidly cooling pipe.
(2) the bright heat treatment furnace mesh belt type.This type furnace is suitable for small diameter thin-walled precision steel tube, hour production of about 0.3 to 1.0 tons, processing steel tube length can reach 40 meters, also can handle a roll of capillary.
(3) the muff type bright heat treatment furnace.Steel pipe in a continuous rack, running in the muffle tube heating, can deal with high quality at a low cost small diameter thin-walled steel tube, hours production at about 0.3 tons.
Argon arc welding
Penetration depth of molten stainless steel welded pipe requirements, do not contain oxide inclusions, heat affected zone as small as possible, argon arc welding of tungsten inert gas protection has good adaptability, high welding quality and good penetration performance, its products in the chemical industry, nuclear industry and food industry widely used.
Welding speed is not high is the deficiency of argon arc welding, to improve the welding speed, the foreign research and development a variety of methods.Which has developed from a single electrode welding torch adopts multiple electrode welding torch welding method applied in the production.First introduced in Germany in the 70 s many welding torch along the weld direction alignment, forming a long heat flux distribution and greatly improved welding speed.Generally USES three electrode argon arc welding torch, welding steel pipe wall S p 2 mm, welding speed three to four times higher than that of single welding torch, welding quality is improved.Combination of argon arc welding and plasma welding can be larger wall thickness of steel pipe welding, in addition, 5-10% of the hydrogen in the argon gas, again using high frequency pulse welding power source, it can improve the welding speed.
Many welding torch argon arc welding is suitable for austenitic and ferritic stainless steel pipe welding.
High frequency welding
High frequency welding is used for carbon steel welded pipe production has a history of more than 40 years, but is used for welding stainless steel pipe is a new technology.Its production of economy, make its products more widely used in building decoration, home appliances and mechanical structure.
High frequency welding has the power to different material, outer diameter, wall thickness of steel pipe can reach higher welding speed.Compared with argon arc welding, it is more than 10 times its high welding speed.Therefore, in the production of general use stainless steel pipe with high productivity.
Because of the high frequency welding speed is high, the burr removal difficult to weld tube.At present, the high frequency welded stainless steel pipe is not acceptable for the chemical industry, nuclear industry, this is also one of the reasons. Look from the welding material, high frequency welding can weld various types of austenitic stainless steel pipe.At the same time, the progress of the development of new steel grade and forming welding method, also successfully welded ferritic stainless steel AISI409 steel grade, etc.
Combined welding technology
Stainless steel welded pipe of various welding methods all have their respective advantages and disadvantages.How to foster strengths and circumvent weaknesses, several welding methods will be combined to form a new welding technology, meet the demand for stainless steel welded pipe quality and production efficiency, is the new trend of the current stainless steel welded pipe technology development.
After recent years of exploration research, combination of welding technology has made progress, Japan, France and other countries of the stainless steel welded pipe production had mastered a certain combination of welding technology.
Combined welding methods are: argon arc welding and plasma welding, high frequency welding and plasma welding, high frequency preheating plus three welding torch argon arc welding, high frequency preheating plus plasma and argon arc welding.Combined welding welding speed is very significant.To adopt the combination of high frequency preheating welded steel pipe weld quality and conventional argon arc welding, plasma welding, the welding operation is simple, easy to implement the whole welding system automation, this combination is easy to interface with the existing high frequency welding equipment, low investment cost, the benefit is good.