Welding required/Weldable fine grain steels, quenched and tempered (Steel grade PT610Q) ISO 9328-6 4

[tranmylinh]

Hi everyone,
Can you support me in welding requirements with thickness 32 mm in sphere tank following ASME VIII div 1 with teachnical specification: Material is Steel grade PT610Q (ISO 9328-6, Weldable fine grain steels quenched and tempered) Yield strength min. 490 Mpa, Tensile strength min 610 Mpa
+ Equivalent material in ASME IX (P.No and Gr.No)
+ Min. Preheat temperature and max interpass temperature
+ Post weld heat treatment ( minimum temp. and holding time)
+ Hardness testing requirement for PQR
Thank you & Best regards.

 

[pradipgoswami]

Hi Tranmylinh,

If your analysis tells that the steel in question is equivalent to SA 724GrA, then a few words of advice:

[li]this steel is a C-Mn, Q&T steel developed and exclusively used for layered(multi layer) pressure vessels[/li]
[li]the present ASME Sec-II , SA 724 spec restriction is up to 7/8" for 724 Gr A material.[/li]
[li]Welding electrodes, SMAW-E-9018M, SAW- equivalent 90 Ksi or more grade(we used to use Thyssen welding products)[/li]
[li]For layered pressure vessel, typically 1/4 or 1/3" thick plates used be rolled in, welded without PWHT. No cracking issues. We used to fabricate tons of layered pressure vessels (Urea & Ammonia Reactors) using this steel.[/li]
[ul]
[li]In your case as plates are 32 mm, PWHT would be mandated.[/li]
[/ul]

Welding with the above suggested consumables would be advisable.PWHT needs to be done at least 50 Deg C below the tempering temperature. If there is any hardness restriction then choosing the correct PWHT temperature would be crucial.

Look through the product catalogues of European Consumable manufactures for welding solutions.

Thanks.

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299

 

[tranmylinh]

Dear Mr pradipgoswami,
For welding electrodes, I am going to used to FCAW-AWS A5.29 / ASME SFA5.29 E91T1-K2C which is designed for the welding of low alloy steel such as 600Mpa grade high strength steels. So can you give me advice anymore?
Thank you for your time.

 

[weldstan]

I would advise checking Al content to assure that it was used in fine grain melting if the specification did not so state. Impact properties in the PWHT condition will be adversely affected if Al was not used. Note that fine grain can be achieved with Nb and/or V additions only.

 

[weldstan]

The adverse impact properties will be seen in the HAZ.

 

[tranmylinh]

Dear Mr weldstan,
In MILL'S CERTIFICATE by Supplier, Al was not used. So PWHT will be applicable or not. Can you give me advice anymore?
Thank you for your time.

 

[weldstan]

It may well have been used but not reported. That is the reason to check. Take a sample and take it to a lab for analysis.