dearator dish end 1

[hyl]

hello member
we are constructed new dearator the material choose is SA 516 GR 70 the thickness of the dish end 25mm and the shell is 16 mm .the question is that.
1-the welding of the dish end need to be post weld heat treatment for that thickness .
2-the reduction of thickness in the dish end for welding arrangment is more than 30% of the plate thickness .what the expert coment please.
3-the hardness of the dish end is 210 BH cause of manufacture .what the idea about this limt .
4-the material size is not avaliable so we use two welded plates for manufacturing the dish end .what is the coment of expert please.
thankx for reply

jamil a alshahed nama
hartha power station

 

[gr2vessels]

jamil,
I'm not "The expert" you are looking for, but I know a thing or two..
1. the dished end should be delivered normalised from the manufacturer, but after welding it to the shell you don't need the PWHT.
2. for the joint of the dished end with pressure on the concave side use UG-32(l) and the type of joint shown on UW-13.1(l) or (m). You have to taper down the skirt (if is thicker than the shell, I assume a SE 2:1 dish) on a 3:1 ratio, down to 16mm.
3. 210HB is fine.
4. the plates can be welded together, then ground flush and fully radiographed, prior to forming.
cheers,
gr2vessels