Friday, October 8, 2010

[MW:7454] Re: Why IGC Samples of PQRs fail?

Dear Mr. Makwana,

What possibly can cause rejection is the chemical composition of the
base material. This SA 387 Class 22 can contain Carbon up to 0.15 %
and contains Chromium 2 - 2.5 %.
I don't know if you have values about the chemical composition for the
clad layer but it's very important that carbon will be < 0.03%.
Especially when performing PWHT at 690°C for 26 hours.
This temperature range is very critical for carbon containing
stainless steels because of the formation of Chromium Carbides which
will reduce the Chromium content near the grain boundaries and this
will cause IGC attack during ASTM A262 Practice E.
Is it really necessary to perform PWHT at such high temperature? SA
387 specifies 675 °C as a minimum for Tempering after Quenching but
says nothing about the temperature for stress relieve after welding
and in my opinion this should never be higher than the tempering
temperature of the parent metal.

Best Regards,

Herman Pieper

On 7 okt, 13:59, jignesh makwana <jkmakwa...@gmail.com> wrote:
> Dear All, Dear Jeff, Please look into.
> Please find the attachment
> All the PQRs have been failed except one sr. no. 4 in IGC testing as ASTM A
> 262 Practice E.
> Can anybody suggest me any solution or any reason??
> Preheating @ 100 C
> Interpass @ 150 C
>
>  Details of PQRs.xlsx
> 14KWeergevenDownloaden

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[MW:34820] RE: 34813] Clarification in Rate of heating and cooling.

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