[MW:11516] MW:11496: Temper embrittlement

Mr. Thakkar,

I think you're talking about API-934A-Recommended Practice for Materials and Fabrication of 2 1/4Cr-1Mo (P-5A), 2 1/4Cr-1Mo-1/4V(P-5C), 3Cr-1Mo(P-5A) & 3Cr-1Mo -1/4V(P-5C) Steel Heavy Wall Pressure Vessels for High Temperature, High Pressure Hydrogen Service.

The scope of this document: This RP presents materials and fabrication requirements for new 2–1/4Cr and 3Cr steel heavy wall pressure vessels for high temperature, high pressure hydrogen service. It applies to vessels that are designed, fabricated, certified and documented in accordance with ASME Code Section VIII, Division 2, including Appendix 26, Mandatory Rules for Cr-Mo Steels with Additional Requirements for Welding and Heat Treatment and ASME Code Case 2151, as applicable.

This document may also be used as a resource when planning to modify an existing heavy wall pressure vessel.

For high temperature hydrogen service(hydro processing) the above materials are the only industry accepted materials. Unfortunately P-5B materials see below are not proven and haven't been accepted by API. That's why there's no requirements of temper embrittlement test for these steels.

Hope this clarify the doubt.

Thanks.

Pradip Goswami,P.Eng.IWE

Welding & Metallurgical Specialist & Consultant

Ontario,Canada.

Email-pgoswami@sympatico.ca,

pgoswami@quickclic.net

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Maulik Thakkar
Sent: Monday, June 27, 2011 12:51 PM
To: materials-welding@googlegroups.com
Subject: Re: [MW:11496] Re: Temper embrittlement

Thank you for giving reply but P5C also contains more than 0.15% Mo & still need temper embrittlement test but not for P5B!

On Mon, Jun 27, 2011 at 1:53 PM, mohd.qce <mohd52100@gmail.com> wrote:

Dear maulik,

Temper embritllement can be prevented by keeping sulfer an phosferous
at low level and also addition of Mo(<0.15% min) will prevent temper
embritllent.

As far as my interpretaion SecIX all P5B materials have a more than
0.5%Mo. so that not required.

It really intersting subject..if get more info please share with us.

regards,
mohd.

On Jun 26, 11:28 am, "Maulik H. Thakkar" <mlkthakk...@gmail.com>
wrote:

> Dear all,
>
> Why temper embrittlement test is not required for P5B materials as per
> API 934?

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Regards,

Maulik H. Thakkar

Larsen & Toubro, Hazira

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