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[MW:1532] Re: Significance of HOT PASS

By Materials & Welding
Dear Rafique,

I'm an international welding technologist and perform a lot of weld
inspections but I never accept stop welding when only root layer is
applied. In my opinion also international regulations won't accept
such. One of the most important reasons is the possibility that cold
cracks arise in the root layer. If you still need to stop after the
root layer in my opinion you have to perform NDT in front of welding
to ensure that there are no cracks in the root pass, after that I
would propose to preheat up to 75 - 125 °C in order to remove any
possible moisture arised because of cooling down after root layer.

Best Regards

Herman Pieper

On 8 feb, 18:16, rafique naik <rafiquen...@hotmail.com> wrote:
> Please let me know for A 106 B 16'' dia  12.7 mm thik pipe to pipe butt joint, if after root pass joint is left as it is for overnight and next morning welder wants to continue with hot pass, can he do welding  without any pre heating..
>
> Regards
>
> Rafique
> _________________________________________________________________
> Wish to Marry Now? Join MSN Matrimony FREE!http://www.in.msn.com/matrimony

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