Alloy stels PWHT - Hydrogen Bake

Zakaria ghrab

unread,

Mar 31, 2012, 6:20:20 AM3/31/12

to material...@googlegroups.com, material...@goolegroups.com

Dear Experts,

need some reference / support from ASME B31.1 for performing hydrogen bake in alloy steels when is not possible to do immediatly PWHT after Welding for any case.

- What's minimum time after welding when it's mandatory to perform this intermediate cycle

- Holding time and temperature !

- Others requirements (if any)

I know that it's necessary to perform this heat treatment but i didn't get support from Code.

Regards

CHINTUKUMAR GANDHI

unread,

Mar 31, 2012, 11:04:23 AM3/31/12

to material...@googlegroups.com

Dear Sir,

First of all P No. of Alloy material shall be mentioned. If it is P 5A & 5B then as per FW's specification if t </= 13 mm.- Cool under insulaiton to ambient temp., If 13<t</=25 mm.- 350º C. for 2 hours, If 25<t</=50 mm.- 350º C. for 4 hours, If t> 50 mm.- Intermediate S.R. at 600º C for 2 hours or 650º C for 1 hour.

Might the above be helpful to you.

With regards,

C. R. GANDHI

(MANAGER- Q. A./ Q.C.)

--- On Sat, 3/31/12, Zakaria ghrab <zakari...@gmail.com> wrote:

--
To post to this group, send email to material...@googlegroups.com
To unsubscribe from this group, send email to materials-weld...@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.

pgoswami

unread,

Apr 1, 2012, 4:05:57 PM4/1/12

to material...@googlegroups.com, zakari...@gmail.com

Zakaria,

The term Hydrogen Bake out originated from performing weld repairs on hydrogen charged components. For a new construction it's often referred to as "Post-Heating or post weld hydrogen bake out". In ASME Sec-IX PQR forms its' classified under QW 406,(QW 406.11) others. In ASME Sec-IXit is an essential variable, but if specified in the WPS or asked in the design construction specifications it requires to be followed. Omission of this would not call for requalification of the PQR, but would be considered as a deviation from a good engineering practice.

Note:- If the welding consumables are procured with H4 requirements for SMAW and H5 for SAW, for Low alloy steels up to 2.25Cr-1Mo this practice could be avoided.

The extracts from D-10.10 is attached here for your info. You may follow these guidelines for new construction also for B-31.1 code.

Pradip Goswami,P.Eng.IWE

Welding & Metallurgical Specialist & Consultant

Ontario, Canada.

Email-p...@sympatico.ca,

pgos...@quickclic.net

Pradip Goswami,P.Eng.IWE

Welding & Metallurgical Specialist & Consultant

Ontario, Canada.

Email-p...@sympatico.ca,

pgos...@quickclic.net