In a message dated 2/20/04 8:22:27 PM Pacific Standard Time, firstratefab@citlink.net writes:
I would venture that there is no grade of steel available for building a vessel that is not available as pipe. Pipe is inevitably attached to a vessel, that pipe equals or exceeds the mechanical properties of the vessel itself. Could you be specific in exactly what steel you are suggesting?
I won't speak for Dan, but I can venture an educated guess. You're probably correct with respect to grades of steel for standard pressure vessels (outside my scope of knowledge). Even though most of us will not be required to comply it, many/most of us are biased to one degree or another by the American Bureau of Shipping (ABS) RULES FOR BUILDING AND CLASSING UNDERWATER VEHICLES, SYSTEMS AND HYPERBARIC FACILITIES or similar international standard (e.g., Lloyds). In the case of ABS, it allows the following types and grades of steel:
ABS Hull Grades CS, E, EH32, EH36
U.S. Navy Grades HY-80 and HY-100 per MIL-S-16216
ASTM A516 Grades 55, 60, 65, 70
ASTM A537 Class 1 and 2
ASTM A517 Grades, A, B, E, F, J
I suspect that part of the reason these grades were chosen were their suitablility for post-weld stress-relief via heat treatment ... also part of the ABS standard. I haven't begun construction yet but I have pretty well narrowed my choice down to one of the grades of ASTM A516 for mine. BTW, it's good to have a (another?) knowledgeable "pipe and pressure vessel guy" to broaden the group's knowledge base.
What type of steel are you planning on using/have you used for yours? Why did you choose it? Any heat treatment planned or used?
Any tips, pointers, sources, suggestions, etc., on hemispherical endcaps?
Warm Regards
Shawn