Welding repairs are not allowed after heat treatment
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The standards state that \"welding repairs are not allowed after heat treatment,\" but there are exceptions, and situations arise where welding repairs are necessary after heat treatment. How do I proceed? Personally, I think that if the area and depth of the weld repair are not large, stress can be relieved after welding by heating it with a cutting torch (to a temperature of 500–600°). Please discuss the rationality. Thank you
As a novice designer, the exception I’ve encountered was when the heat treatment equipment arrived at the site and pre-welded parts were still needed; in such cases, there’s little else to do but turn a blind eye. I think that even for localized heat treatment, it can’t be as simple as using a gun to apply heat – doing that might only make things worse. What do others think?
Use an electric heating strip to control the temperature properly
There’s no other way; we’ve done this many times before. Heat treatment requires specific rates for heating and cooling, and this process takes approximately 3 hours. Heating with gas welding and then wrapping it in insulation material for natural cooling far fails to achieve such an effect.
In extremely special cases, it may be possible to omit heat treatment, but this depends on the material and the operating conditions of the equipment. For ordinary containers and common carbon steel and low-alloy steel materials, within certain limits, welding repair can be carried out using techniques such as preheating, post-heating, and tempering of the weld seam, in order to avoid heat treatment.
It seems you have in-depth knowledge of heat treatment; truly an expert in this field, haha
The main purpose of post-weld heat treatment is to reduce welding residual stresses. Why are there residual stresses after welding? It is because there are extremely large temperature gradients and structural constraints in local areas during the welding cooling process. Local heat treatment also results in large temperature gradients within a local area; therefore, whether it can reduce welding residual stresses depends on the specific structure as well as the heating and cooling methods used. Using a heating gun for localized heating carries significant risks; the heating process can cause excessive deformation in certain areas of the structure, while cooling can result in residual stresses.
Is a heating strip commonly used for the heat treatment of pipes?
Could you provide a detailed introduction to electric heating strips?
This post was last edited by 15837357920 on 2015-6-25 08:44. Electric heating strips can be found online. It is usually 300mm*1200; the specifications can vary. It is made of ceramic tiles, with a resistance heating wire inside. External power supply control.