Do all welding materials need to be specified on the drawings?
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When looking at the technical specification tables in the technical drawings for chemical processing equipment, there is only one table related to welding materials – one that lists electrodes. If the equipment manufacturer uses other welding methods, does he still need to contact the design team to obtain their approval? According to Article 7.4 of HG20581, the approval of the design team is required. But why aren’t the welding materials for submerged arc welding and tungsten inert gas welding listed in those technical tables? What are your thoughts on this issue?
Hehe, it depends on the specific circumstances. For example, in our drawings, we usually only indicate the welding method, not the welding materials (since we are the same organization as the manufacturing factory, there is no need to specify them). Our manufacturing plant has its own welding technology laboratory, so generally the modified forms of welding notches do not require our design approval (when it comes to welding, they are more professional than we are). But I think it’s better for them to get our consent, yet this has become a *habit, so we don’t really pay it any mind. If design and manufacturing are carried out by two separate entities, I think it is absolutely necessary to specify both the welding methods and the welding materials. If the equipment manufacturer uses different welding methods or materials, they must contact the design team and obtain their approval. After all, it involves an issue of responsibility.
It would be simple if it were just a matter of designing and manufacturing one unit. Our company receives drawings from other organizations, which only list the types of welding rods used; there is no information regarding materials such as those used for submerged arc welding or TIG welding. It’s also troublesome having to get in touch with them.
The electrodes to be used for welding the same material together or for welding different materials must be specified in the technical requirements; this must be clearly stated, and the manufacturing factory should not be allowed to decide on its own. If they have different opinions, those can be discussed. Design changes or other measures should be taken; otherwise, if problems arise with the welding materials, it will be difficult to determine who is responsible.
As per the design requirements, the technical specifications for welding must be indicated on the drawings. If any changes are made to those specified in the technical specifications (such as the welding method, etc.), approval from the design unit is required, and the design unit shall issue a design modification order.