【HaiChuan Discussion】Is it useful to use shot blasting after container welding to reduce weld stress? ? ?
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This post was last edited by Desert Fish on 2021-12-5 09:47. What’s the effect of shot blasting the entire weld after welding? It seems that shot blasting can also help reduce stress. There are now portable shot blasting machines available. @gn_1984 @RedLee_ZZHI @ZhizheMing @Shutong @RefineryWorker
This post was last edited by Shutong on 2021-12-4 at 22:15. There are various methods to eliminate welding stress, with heat treatment being the most effective. The greatest advantage of using a shot blasting machine is rust removal; shot blasting involves using a rapidly rotating impeller to throw small steel or iron pellets at the surface of the parts, thereby removing the oxide layer on their surface. At the same time, steel or iron pellets strike the surface of the part at high speed, causing the lattice structure on that surface to become distorted and deformed, which increases the surface hardness. This is a method for cleaning the surface of parts; shot blasting is commonly used for cleaning the surface of castings or for strengthening the surface of parts. Furthermore, using steel shot for uniform knocking to counteract the welding stresses in components has very limited effectiveness; in particular, blasting should never be used as the primary method for stress relief in containers.
It just occurred to me – when I was in school, I went to a factory for an internship, and the people there explained that the remaining height of the material after processing could be used to reduce stress. This is especially true for stainless steel equipment, which is not easy to treat thermally
Three stress-relief methods: heat treatment, mechanical vibration, natural aging
It is said that machining is also an option, such as grinding off the excess height of the welds
This seems not to be possible. Especially welding the tank is even more impossible.
Thirty years ago, I saw a boiler factory using sanding belts to grind welds
Heat treatment is an effective method for evenly eliminating stress; it is impossible to achieve even stress elimination merely by grinding the weld seam.
The subsequent welds undergo a heat treatment process with respect to the previous welds; the greater the restraint on the later welds, the more so. Some studies suggest that by grinding off the last weld pass – which is sometimes also referred to as a stress-relief weld pass – the peak stress throughout the entire weld structure can be reduced