I am giving my opinion based on experience.
As HIC requirements are there PWHT has to be carried out at minimum 620 C to maintain the hardness within limit. On the other hand thickness of Plate is 132mm where after simulation of 11 hrs Tensile properties goes down specially in core (middle crosssection of plate). When tensile test from 1/4 T or 1/2 T taken there are possibility that UTS value goes below 485MPa.
Solutions
1)If client spec does not specify for simulation of extra cycle, ask mill to do test for reference and if pass no issues. If it fails just keep those value for reference.
2)Try to convinve Client to accept the PWHT Cycle with lower soaking time (ASME). I am not sure which design / manufacturing code is being used.
3)Check with design people if you use Gr 60 or Gr 65 instead of Gr 70, so that dropping of tensile strength can be taken care. These grades Mills can supply easily
Regards.
CK
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C. K. Purohit
Eng-Tech Weld1
Sr Welding Inspector
-- As HIC requirements are there PWHT has to be carried out at minimum 620 C to maintain the hardness within limit. On the other hand thickness of Plate is 132mm where after simulation of 11 hrs Tensile properties goes down specially in core (middle crosssection of plate). When tensile test from 1/4 T or 1/2 T taken there are possibility that UTS value goes below 485MPa.
Solutions
1)If client spec does not specify for simulation of extra cycle, ask mill to do test for reference and if pass no issues. If it fails just keep those value for reference.
2)Try to convinve Client to accept the PWHT Cycle with lower soaking time (ASME). I am not sure which design / manufacturing code is being used.
3)Check with design people if you use Gr 60 or Gr 65 instead of Gr 70, so that dropping of tensile strength can be taken care. These grades Mills can supply easily
Regards.
CK
2009/11/23 Rana, Jignesh <jignesh.r@thyssenkrupp.com>
Dear All,I have an equipment to be installed in sour services.Material – SA 516 Gr. 70 (HIC tested plates), 132 mm thickness.For PWHT the soaking time is 5.30 Hrs as per project specification. Considering one cycle for future site / modification requirement, the total simulation time works out to be 11 Hrs.PWHT Temperature – 620 Deg .C.What would be behavior of material below LOWER TRANSFORMATION TEMPERATURE (P No. 1), against this cycle? (Tensile property, Impact property).All reputed mills are denying for supply with the simulated testing condition (620 DEG C and 11 Hrs. Soaking Time).Regards,JIGNESH R RANA
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C. K. Purohit
Eng-Tech Weld1
Sr Welding Inspector
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