Development of welding procedure for fillet welds
Thread Content
The main body of the equipment is made of δ30, 16MnR material, while the nozzles are forged from δ60 material. 1. When developing the welding procedure, should it be based on a procedure evaluation tailored to the wall thickness of the cylinder, or on a procedure evaluation that takes into account both the nozzles and the cylinder? 2. Welding procedure qualifications covering 30–60 mm all require heat treatment, while the equipment itself does not need heat treatment. When carrying out welding procedures, is it feasible to choose a welding procedure qualification that covers 30–60 mm and to apply local heat treatment? 3. If the process qualification is determined solely based on the cylinder wall thickness, heat treatment is not required.
When making the assessment, it should be possible to include the actual butt thickness during the joining of the take over to the cylinder; if this is already the case, then it is not necessary.
I still don’t quite understand after reading the original poster’s explanation. First, it is necessary to determine whether the product requires heat treatment. If no heat treatment is needed, then welding procedure qualifications that can cover two different materials and thicknesses should be selected (multiple such qualifications may be used). For structures with full penetration, welding procedure qualifications specific to full penetration types are also required. If heat treatment is necessary for the product, then welding procedure qualifications appropriate for heat treatment should be used (it should also be noted that there is an issue related to covering the heat treatment time here)
1. The equipment itself does not require heat treatment. 2. Do you mean that multiple evaluation codes can be used to cover δ30 and δ60? For the evaluation of δ60 in our factory, heat treatment is required; are local heat treatments for the fillet welds also necessary?
In my opinion, for ordinary welding tasks, a 30mm weld evaluation is sufficient； Saddle-type joint welding, using 60mm weld evaluation ； My basis is the weld height.
The process qualification shall cover the thickness of the nozzles and the shell. If the equipment does not require heat treatment, then process qualification support that covers 30 and 60 without heat treatment is needed.
Similarly, what category do the weld joints formed between the internal components and the shell in pressure vessels fall into? What category is generally assigned to them? Class D? Still. . . . .
“Our factory currently determines that δ60 requires heat treatment. Have you completed the welding process evaluation? If it’s already done, then what’s the need for “heat treatment”? If the equipment does not require heat treatment, why still conduct a process evaluation for heat treatment? Since the equipment does not require heat treatment, there is no need to select a process evaluation for heat treatment. If the equipment does require heat treatment, then a process evaluation for heat treatment should be chosen. In this case, it is not necessary to perform heat treatment on the fully penetrated test specimens, as heat treatment is used to improve the mechanical properties of the welded joint, while the fully penetrated test specimens are merely used to ensure that the welded structure achieves full penetration; the focus is on full penetration. I wonder what specifications have been used for the process evaluation of butt welding of 16MnR steel using manual shielded arc welding in your company? We have produced them in three sizes: 6mm, 16mm, and 40mm. If these three sizes are chosen, a process evaluation using the 40mm size will be sufficient to cover both 30mm and 60mm cases; additionally, an evaluation using a fully penetrative test specimen will also suffice
The process qualification has been carried out previously; the qualification for weldable metal thicknesses of 60 mm involved heat treatment. If certain qualifications are selected that are compatible with the process qualification, local heat treatment of the fillet welds will be required. “\"Since the equipment does not require heat treatment, there is no need to choose a process evaluation for heat treatment.\" This is because there are no process evaluation standards for unheat-treated materials in the 30–60 mm thickness range. The standards specify that steel with a thickness greater than 30 mm should be heat-treated; therefore, it is better to carry out heat treatment considering the thickness
I understand now. That means the product requires heat treatment. The fillet welds you’re referring to are probably the welds between the fully penetrated tubes and the cylinder, right? When using this structure for the process qualification of fully penetrated specimens, heat treatment is not necessary for the process qualification!