Heat Treat 516-70 to 50 ksi

[mattf11]

Does anyone know the proper heat treatment process to obtain a 50 ksi min Y for A-516-70? We spec'd out a-572 Gr50 but get deviation reports from our fabricator stating that 516-70 was used. These plates are for pad-eyes on +20 ton weight units for offshore service.

Any help is much appreciated.

 

[metengr]

I would not recommend altering the heat treatment of ASTM A-516 plate (specified min Tensile/Yield) to achieve a 50 Ksi min yield strength. If you need 50 Ksi min yield strength, I would suggest going to one of the HSLA steel plates, like ASTM A 529, A 533 or A 514 Grades.

 

[stanweld]

Most A 516-70 plate under 1" thick actually has over 50 Ksi Y.S. Assuming that the plate supplied did not have adequate Y.S., my recommendation concurs with metengr's. The vast differences in Carbon Equivalent of A-516 from heat to heat and manufacturer to manufacturer and thermo-mechanical processing make defined heat treating procedures exceedingly difficult if not impossible on a general basis.

 

[mattf11]

Thanks for the advice. Would having impact requirements change any of your thoughts? I need 3 tests, min average 20 LB-FT (27 joules) at -4°F. with no one test below 15 LB-FT.

Thanks again!

 

[stanweld]

Even more so. You should demand your fabricator to correct its nonconforming product at its expense by supplying the correct material supported with CMTRs in compliance with your specified requirements.