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What’s Induction Post-weld Heat Treatment & Its Advantages?

  Production is a very rigorous thing, especially since the production of industrial products is often time-consuming and expensive, so we should pay more attention to the quality of the finished products in the production process. Therefore, in order to increase the ductility and toughness of the weld and improve the production quality, we need to heat the weld.

So what is post weld heat treatment? Why is post-weld heat treatment necessary?

  Induction post-weld heat treatment is a process used to eliminate residual stress of welded joints, improve weld structure, and improve joint toughness.

So what is the importance of post-weld heat treatment?

  • Eliminate welding residual stress

  After the welding is completed, residual stress may appear, so in order to prevent the deformation of the workpiece and improve the performance of the material and welded components, we need to eliminate the residual stress with post-weld heat treatment.


  • Reduction of hardening

  After post-weld heat treatment, the residual stress is reduced, the plasticity and toughness of the weldment are improved, and the hardenability is reduced.

  • Expel hydrogen

  Hydrogen will cause brittle fractures of welded joints in use, so it is very important to discharge hydrogen. In the heat treatment process, when the temperature rises, hydrogen will overflow outward. When the heating temperature reaches below 300 °C, keep it for 2-4 hours, and it can be removed. Hydrogen, heating temperature to between 550 ℃ -650 ℃, can achieve hydrogen removal.

  • Anticorrosion

  For stainless steel products, the residual stress of the welded structure will reduce the corrosion resistance of the material, and the post-weld heat treatment removes the stress, which can play a role in corrosion resistance.
At present, the post-weld heat treatment generally adopts a single high temperature tempering, normalizing, and high temperature tempering.
For gas welding joints, normalizing and high temperature tempering are used. This is because the grains of the gas welding seam and heat affected zone is coarse, and the grains need to be refined, so normalizing is used. However, single normalizing cannot eliminate residual stress, so high temperature tempering is required to eliminate stress.

  A single medium temperature tempering is only suitable for the assembly and welding of large ordinary low carbon steel containers assembled on site, in order to partially eliminate residual stress and remove hydrogen. In most cases, a single high temperature tempering is used. The heating and cooling of the heat treatment should not be too fast, and the inner and outer walls should be uniform.

Zhengzhou Ketchan Induction Post-weld Heat Treatment:

Pipe preheating before welding, heat treatment after welding:

Pipe preheating before welding heat treatment after welding

Insulating skeleton, winding electromagnetic wire, fast heating the whole roll:

Insulating skeleton winding electromagnetic wire fast heating the whole roll

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