Need advise to clarrify client - Dish head stress relieving simulated PWHT test panel

[murugesan jeyaraman]

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

 

 

 

 

[Karthik]

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 <jmuru...@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.

[Eswaran samikannu]

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 <karth...@yahoo.com>
To: material...@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

-- To post to this group, send email to material...@googlegroups.comTo unsubscribe from this group, send email to materials-weld...@googlegroups.comFor 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.

-- To post to this group, send email to material...@googlegroups.comTo unsubscribe from this group, send email to materials-weld...@googlegroups.comFor 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.

[sudhakar kuppuswamy]

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

With regards,
Sudhakar.k

[murugesan jeyaraman]

Yes, as per Drawing we have to comply with ASME and Australian standard

[Karthik]

Hi, Was this vessel installed at Australia or Newzealand? Also please verify your design calculation,whether the vessel was designed to AS1210 or ASME. If the vessel designed to AS1210 and installed at Australia then you have to follow AS4458(Construction Code). Or if the vessel designed to ASME,then you can inform to your client that we have followed ASME for construction too. Even if the customer stick on AS4458 requirement,you can inform them that we will do SR and Mechanical test on a sample piece with the same Material grade to prove that the mechanical properties are within the code requirements.This is only the option if the customer need for AS4458 requirements.

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

[vaibhav Joshi]

Dear,

I am not sure but you can try this for an explanation.

As per ASME sec-VIII div.1 simulation PWHT of P1 material is not required,

There is another parameter(Larsen miller) to identify the equivallent  heat treatment for a material,in which on the basis of TC you can calculate Tp for Min and Max heat treatment temp and time. Now calculate the Tp for actual heat treatment and prove that your actual Tp is within the range. 

Tempering parameter (TP) : (Larsen Miller parameter)

 

Parameter for calculating equivalent heat treatment

Conditions as follows:

 

TP = (T+273)(20+log10t)×10^-3

 

Where T = holding temperature (°C), t = time (hours)

This is not acceptable as per code but technically you can give additional clarification along with test coupon of same grade.

Regards,

Vaibhav Joshi

[Biplab Pal]

Dear Jegan,

 

You are right that PWHT is the part of welding.

PWHT is generally done in 3 condition for steel 1. Below the Lower critical temp, 2. above the lower critical temp & below the upper critical temp and 3. above the upper critical temp.

 

Where as SR is the one kind of PWHT condition1 only for residual stress relieve.

Go through the Iron carbon equilibrium diagram & TTT diagram for detail of grain & microstructure.

Thanks & Regards

Biplab Pal
Industrial Services, Inspection Engineer.
SGS India Pvt. Ltd.
Kolkata Branch

E-mail:   bipla...@gmail.com
 
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