simulated post-weld heat treatment (SPWHT)

[ahmadire]

Please share your thoughts herein,
How is SPWHT done? ٌWhat is the exact need for SPWHT at plate mill?

 

[pradipgoswami]

This test is to done at the mill, during production & heat treatment of plates/forgings(base metals) prior to dispatch. Under the present steel making scenario and knowledge base one may not have to ask this for all types of materials. However if the design Code is Sec VIII, DIV-2, and design requirements are very stringent and for critical operations, then vendors have this flexibility to ask for this requirement for overall integrity of the fabricated component . The intention is to evaluate the mechanical properties (tensile & charpy impact especially) conforming to the special/additional heat treatment requirement and meeting the design code/project specifications' requirements..

For example: Say materials is Cr-Mo-V steel PWHT envisaged as the design code is 4 hrs. Fabricator foresees the problems,and anticipates that there would at least one or 2 Full fledged repair cycle even after PWHT. So with additional 2 cycles(8 hrs) of PWHT what should be the mechanical properties? One may ask those information from the mill to be verified prior to delivery.

However it comes with a cost and may delay the delivery.

Requirements are specified in ASME Sec-II,Part-A,,SA-20, Supplementary Clause S3



Thanks.

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299
All provided answer are personal opinions or personal judgements only. It's not connected with any employers by any means.

 

[ahmadire]

pradipgoswami What will force us to ask for it? Having PWHT in our manufacturing process or impact test or ...? If we have 1 cycle PWHT would it be needed to be asked for?

 

[fleischfresser]

Pradipgoswami,

SPWHT is required in the scope of ASME VIII/1 and VIII/2 – see HEAT TREATMENT OF TEST SPECIMENS (UCS-85 and 3.10.2).


Regards - Juergen

 

[pradipgoswami]

Requirements for simulation test coupon are driven by the following requirements:-

-Design and Construction Code
-Any additional design conditions imposed, client/project specifications
-Materials of Construction, and thickness(thicker materials may have anistropy and simulation HT is generally called for to safeguard the integrity of the products)
-Design Temperature Envelope(i.e the design temperature of the components being fabricated.

Could you please elaborate the above requirements.

Thanks



Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299
All provided answer are personal opinions or personal judgements only. It's not connected with any employers by any means.