SA387 Gr12 CL12 Tensile strength out of standard

[susan_cui]

Dear All,

I have one question need your support:
for material SA387 Gr12 CL12, Tensile strength specified in ASME II-A is 450~585 MPa.
in case actual tensile strength is 620MPa, others properties incl. Yield strength, impact test value, hardness can meet standard requirement, the material can be acceptable? can we re-do heat treatment to reduce tensile strength to 450~585 MPa?
Thanks!

 

[metengr]

Check your tempering temperature on the MTR. This material was most likely supplied as normalized and tempered. If the mill tempered at 1150-1175 deg F, I could see the higher UTS since all other tensile properties are specified minimum values with no maximum value.

I would temper at 1175 deg F to 1200 deg F.

 

[susan_cui]

Hello, metengr. thanks for your reply.
correct, the material delivery condition is N+T.
in case Rm is higher than ASME code(450~585 MPa), i.e. Rm is 620MPa, acc. to your experience, can we accept on deviation? what's the impact on equipment manufacture, welding and operation?
thanks!

 

[metengr]

I would temper at a slightly higher temperature to get the Rm value within specification.

 

[susan_cui]

Yes, we are re-doing temper, and waiting for test result.