Sunday, June 12, 2016

         
Post welding heat treatment for Stainless steel

In laser welding process of stainless steel, the post weld heat treatment is generally required, in particular, Martensitic, ferritic stainless steel, choose the correct preheating before welding and post weld treatment is necessary to ensure the quality of the welding laser welding machine. So what would be like in the end after welding stainless steel heat treatment process?
  Post weld heat treatment on tensile strength of stainless steel, is related with creep limit, heat treatment temperature and time of insulation. Effect of heat treatment after welding stainless steel, the impact toughness is different from the different types of steel. Generally the after welding process of stainless steel, there are two treatment for choice, one is single high temperature tempering , the other is normalizing and tempering treatment.
  1. Normalizing and tempering
  For oxyacetylene welding is tread with fire and high temperature heat. his is because the grains of weld gaps and heat affected zone of welding is coarse, refinement is needed, so the use of normalizing.


2. Single high-temperature tempering
  However single fire could not eliminate residual stress, needs further tempering stress relieving. Medium-temperature tempering applies only to single site Assembly of large General Assembly welding of mild steel containers, which are designed to achieve some stress-relieving and hydrogen. Most of the occasions is the choice of a single high-temperature tempering. Heat treatment for heating and cooling should not be too fast, to inside and outside wall uniformity.
Post weld heat treatment to eliminate the relaxation of welding residual stress of stainless steel stable shape and size of the structure, reducing distortion; weld metal ductility; improving fatigue strength improving stress corrosion resistance ability prevent the occurrence of delayed cracking, stainless steel heat treatment after welding is therefore very important.

Post weld heat treatment to eliminate the slack stainless steel welding residual stress; keep stable structure of shape and size, reducing distortions; improve the ductility of the weld metal; improve the fatigue strength; improving stress corrosion resistance ability prevent the occurrence of delayed cracking etc. So after heat treatment of stainless steel welding is very important.







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