All I have to work n at the moment is a statement that tubes and pipes in these materials are susceptible to hot cracking and should be subjected to higher levels of radiography than reuired by ASME.
Tubes and pipes are for a boiler that will be designed and contructed to ASME Section I.
athomas236;
Where did you read this statement? I have worked with these ASME/ASTM materials for over the last 20 years, and I have not seen a hot cracking problem during normal handling, forming and welding operations.
I agree with metengr. I assume you're concerned with welding these materials. As you know the P1 material is .5 Mo, and should be readily weldable, P12 and P22 are Cr Mo alloys and they do require a higher preheat. In my experience most welders tend to skimp on preheat and maintenance of the proper interpass temperatures. Preheats need to be through wall and extend past the welding area on all sides an amount sufficient to slow the weld cooling, typically several times the wall thickness, say a minimum of 2". The best way I know of to ensure proper preheat is to use temperature controlled heating elements. What wall thickness are we talking about?
