Friday, September 9, 2011

Re: [MW:12397] Stress relieving & PWHT



dear all,

SR can be termed as PWHT ,but PWHT can not be termed as SR always.. we all know SR is done for releaving the residual stress that are formed during welding. But the purpose of PWHT can not be SR always it is also done to reduce the hardness of a material based on Carbon Equivalent (C.E) in case of alloy steels & so on other steels ...so we should avoid interchanging the terms .Looks simple but important while dealing with terms ...!!!!

with regards,
sudhakar.k



On Fri, Sep 9, 2011 at 1:31 PM, Eswaran samikannu <eswaranaws@yahoo.co.in> wrote:
Dear Experts Good Day to all,
 
I want to Clarify Stress relieving & PWHT . In Industry and generally talking and refering the books both words are used interchangeably.
My point of view stree relieving is applicable to the part which are undergone Hot/Cold working Examble like Dish Head,rolled products etc , PWHT is applicable to the welded part , Holding the temperature below the Tempering temperature to relieve stress to few hours depends on Code/End use requirements.
 
Any one can explain temperature of stress relieving , PWHT and any terminology of this two.
 
Any one can define the carbon Manganese steels & where we find the list of this materials, ABS Gr EH36 material fall in this catagory & If we fabricate EH36 material more than 50 mm thick full penetration weld followed AWS D1.1 code need to PWHT,Client nothing specified . 
 
Thanks in Advance
 
By  Jegan  
From: Karthik <karthik6684@yahoo.com>
To: materials-welding@googlegroups.com
Sent: Friday, 9 September 2011 4:17 PM
Subject: Re: [MW:12390] Need advise to clarrify client - Dish head stress relieving simulated PWHT test panel
Hi,
Did u use 3 Codes for your vessel construction? Strange. and how it is possible to use 3 codes in one vessel construction?...
Pls.verify your design and drawing for the Construction Code.If it is specify ASME Sec.VIII-Div.1 .,then you can reply to your customer that you have followed ASME.
Thanks & Regards,

(Karthik)

Karthikeyan.S
QA/QC Manager
Getabec Energy Co.,Ltd.
379,Moo6,Soi8,Nikhomphatana,
Rayong-21180,
Thailand.
Phone: 0066 38 897035-8 (Off)
Fax: 0066 38 897034
Hand Phone: 0066 892512282


--- On Fri, 9/9/11, murugesan jeyaraman <jmurugesan@gmail.com> wrote:

From: murugesan jeyaraman <jmurugesan@gmail.com>
Subject: [MW:12389] Need advise to clarrify client - Dish head stress relieving simulated PWHT test panel
To: materials-welding@googlegroups.com
Date: Friday, September 9, 2011, 2:29 PM

Dear Friends
 
Please offer me your suggestion how we can settle the following case.
 
We fabricated and supplied one pressure vessel to one of our client two years back. Now only they have reviewed our documents and come back with following observations.
 
Code of construction is ASME VIII Div 1 and AS1210 and AS4458, Material SA 516 Gr 70, thickness 30 mm,
 
Our vessel dish head is Stress relieved as per ASME viii Div 1 code requirement, but we have not done any simulated PWHT test panel for this stress relieve treatment.
 
 as per AS 4458, Unless any mechanical  test is done to prove Stress relieved components are restored to their original material properties, normalising is the preferered heat treatment for cold formed components.
 
It is obvious from above that either we have to do SR with Simulated PWHT test panel or Normalising of dished head.
 
Actually we have overlooked AS 4458, so we have only done SR without PWHT test panels, so no mechanical testing was done.
 
At this stage we cannot do normalising as plant is already running.
 
At this stage, we do no have stock of same heat number plate.
 
Please suggest how we can answer this observation.
 
Can we say we have overlooked AS and SR done as per ASME Viii Div 1 as a normal practice in South east asia.
 
We hve not done any Hardness test  being carbon steel material.
 
Thanks
 
 Murugesan
 
 
 
 
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--
With regards,
Sudhakar.k

--
To post to this group, send email to materials-welding@googlegroups.com
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For more options, visit this group's bolg at http://materials-welding.blogspot.com/
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