Hello Sunil/N.Patel
I am not sure whose query is this? As pointed out by Mr Bathula PWHT is mandatory for SA 672 Cl22 steel of 22 mm thickness. Your query does not specify the grade, however I‘m assuming that the material of construction is C.S and for 22 mm thk welds designed to B-31.3, PWHT is mandatory.
You need to speak to your welding engineer and give your constructions guys a back to basics course on welding, including hardness testing. Results of hardness testing are not “reproducible”, every indentation would yield different readings.
In simple word, based on the engineering principles, Spot hardness testing can never be a substitute for PWHT.
Thanks.
Pradip Goswami,P.Eng.
Welding & Metallurgical Engineer/Specialist
Email-pgoswami@sympatico.ca,
-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Raghuram Bathula
Sent: Wednesday, September 29, 2010 12:40 PM
To: Materials & Welding
Subject: [MW:7274] Re: pwht vs hardness
PWHT is mandatory by code for that thickness.
On Sep 29, 9:16 pm, "sunilrathor...@yahoo.com"
<sunilrathor...@yahoo.com> wrote:
> Dear member,
>
> We have an pipe made from SA 672 cl 22 mat having dia 72" and thk 22 mm used for flair line in refinery. The construction people are taking deviation not to do pwht on basis that they will check the hardness value if it comes under limits they will not do pwht.
>
> i want to know that is hardness testing is substitute for avoiding sr or pwht
> .
> Its design base is asme 31.3
> n Patel
Worley Parsons, London
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