Welding issues of shims in heat treatment equipment for ordinary carbon steel
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Everyone, in general, Q345R equipment does not suffer from stress corrosion. The thickness of the cylinder is 42 mm, and the equipment undergoes heat treatment before leaving the factory. Upon arrival at the site, a gasket with dimensions of 300x300 mm and a thickness of 16 mm needs to be welded onto the cylinder. Do the fillet welds around this gasket require heat treatment as well? See GB150-2011, see 8.2.1(d)
This post was last edited by wanlirn on 2021-3-22 at 10:20. The standards are very clear: in the event of such problems on site, it is strictly prohibited to proceed with welding. On-site welding plus local heat treatment involves too many parties involved, so it may not be feasible to carry out. So generally, one can only use shaped steel to make clamps, with gussets welded to the shaped steel, and approval from the client is also required. This is a quality issue that makes it easy for the client to return the product
There are design requirements in the first sentence; if the design doesn’t specify any requirements, then follow what you said.
The 2nd floor is correct. This is probably because the actual manufacturing process wasn’t taken into account during the design phase. One should not get agitated; in addition to stress, the erosion of the material also needs to be taken into account. Although the original poster didn’t specify the material of the backing plate, it still deserves consideration, as the materials used for non-load-bearing components are generally of lower quality than those used for load-bearing components. If the position of the backing plate is too close to the weld site and the backing plate is welded directly, then all the previous heat treatment efforts will have been in vain.
This post was last edited by sylx521 on 2021-3-15 at 15:49. Isn’t there any standard specifying that welding cannot be carried out after heat treatment? I searched for standards for a long time but couldn’t find any source for this rule. Post-weld heat treatment is aimed at the thickness of the weld joint, not the thickness of the shell, right? Although the equipment undergoes overall heat treatment before leaving the factory, the thickness of the welds formed between this 16mm Q345R gasket and the equipment housing is clearly not sufficient to meet the requirements for post-weld heat treatment. Personally, I believe that as long as this backing plate is at a certain distance from the original shell welds, the fillet welds formed after welding this backing plate do not require heat treatment.
The heat treatment specified by the standards is based on the weld thickness. The weld thickness resulting from welding this 16mm Q345R gasket to the equipment housing is clearly not at a level that requires post-weld heat treatment. So heat treatment isn’t necessary. You mentioned that welding is not allowed after heat treatment, but it seems that no standard specifies this clearly.
In accordance with clauses 7.4.3 and 7.4.4 of GB150.4, if it falls outside the scope of clause 7.4.3, welding can be carried out with reference to clause 7.4.4.
The last edit to this post was made by wanlirn on 2021-3-16 at 08:34. Just a reminder: pay close attention to page 39 of the regulation that we use frequently, so as to avoid any problems in the future