I have a question regarding the grooves for flange butt welding
Thread Content
Hello everyone, I’m a beginner and would like to ask you all a question regarding the groove for flange butt welding. The weld assessment description indicates a thickness range of 14–28 mm; a 14 mm 60° V-groove was used for the assessment ； However, according to flange standards, when the wall thickness exceeds 22 mm, a combined groove must be used. In this case, compared to the previous single-V groove, does the use of a combined groove alter any important evaluation factors? Is it necessary to make changes to the weld qualification? If necessary, should the coverage thickness for the weld evaluation be changed to 14–22 mm? If it’s not necessary, are there arguments to support the view that combining grooves and a single V-groove constitutes no significant change? I hope everyone can give me some guidance; thank you all!:handshake
Firstly, for your procedure qualification, you used 14mm thickness. There are impact performance requirements. Therefore, the range of base material thickness is 14–28 mm. Since you know about these important variables, you should investigate which ones are important variables, which are additional important variables, and which are not important variables. In the procedure qualification rules, changing the groove is a non-critical variable. To change the non-critical variables, you just need to adjust your welding procedure. Either upgrade it, or write a new one.
When considering the groove type, the thickness of the weldment is generally taken into account; if a large amount of metal needs to be fused, then a narrow groove type should be considered. The thicker the welded piece, the more attention should be paid to this aspect.
Welding procedure qualification can basically cover welding with a thickness up to twice that of the test piece.