PWHT and test specimen

[mdischarge]

for what kind of material and thicknesses we do simulation test specimens for the tensile analysis after heat treatment?
thanks

 

[metengr]

This is too general of a question. Please provide more information, did you review ASME Section VIII, Part I, UCS-85?

 

[mdischarge]

To Metengr,

I wanted to know if this kind of test is mandatory for the those parts imposed to PWHT?
as we have some columns which licensor mentioned in specification that :

"The affect of heat treatment on tensile strength shall be determined by testing specimens from each heat of plate, pipe, and forgings {small forgings may be tested on
a “lot” basis as defined in ASME Section VIII, Division 1, Section UG-84(e)(2)}The specimens shall
be subjected to the maximum heat treatment.The results
shall comply with the requirements of the subject material specification."

Our Vendor is going to deviate from specification to do this test only for the plates not for the forging parts.
we are going to make a decision if we can deviate from spec or force vendor to do that ,however it's vendor's responsiblity to gaurantee the columns design during life cycle

any advise?

thanks

 

[VeryPicky]

Design gurantee does not always cover the material and fabrication. Your PWHT qualification is important for a couple of reasons. One of them is to confirm design strength of material after a number of cycles. I hope you requested at least one extra cycle for your maintenance.
I see no reason to relax on forging requirements. Where I come from this certification is a part of material test report and welding procedure qualification. Also, in the case of hardness and/or impact requirements minimum PWHT conditions are tested for each material heat.
To add: does the Vendor guarantee cover also the production losses?

Putting Human Factor Back in Engineering

 

[metengr]

An example that comes to mind is a weld procedure specification (WPS) qualification, where mechanical tests are performed to qualify the Welding Procedure Specification for post weld heat treatment (PWHT) of the base materials. This is done to demonstrate adequacy of the weld and base material mechanical properties after thermal treatment. Thermal treatments are based on obtaining desired properties from time at temperature.

So, yes in a round about way thermal treatments that are performed on a material because of PWHT have mechanical tests performed to assure meeting minimum mechanical property requirements.

 

[GenB]

"The affect of heat treatment on tensile strength shall be determined by testing specimens from each heat of plate, pipe, and forgings {small forgings may be tested on
a “lot” basis as defined in ASME Section VIII, Division 1, Section UG-84(e)(2)}The specimens shall
be subjected to the maximum heat treatment.The results
shall comply with the requirements of the subject material specification."

I do not understand at all:
It looks to me that everything asked is in the MTR already
for the material specification for the ASME Material.

 

[stanweld]

One assumes that the Engineer/Owner requires you to obtain MTR's that reflect the post weld heat treatments to be encountered during vessel fabrication in addition to the manufacturers'standard heat treatment; e.g., as formed (none), normalize, normalize and temper, quench and temper.

When you order the material, order it to include the simulated PWHT during your manufacturing process.