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[MW:2751] Re: Weld Crack at Root trough weld metal

By Materials & Welding
If this was for sour gas, you should have a qualified procedure that
also includes a hardness survey. Was NACE Mr0175 or NACE MR0103
specified? Regardless, the weld and HAZ at the root of the joint is
too high. For NACE MR0175, Vickers hardness limit is 250 for HAZ and
weld (or 237 Brinell or 22 Rockwell C) in contact with sour service
environment and for MR0103/RP0472 Vickers limit for HAZ is 250 and
weld is 200 Brinell.

Antonio has a good suggestion for high preheat and using 7010 for
root. Cap hardness limit is higher since it is not directly incontact
with sour environment so 8018 would most likely be acceptable. I don't
have experience with the API 5L X65 so I don't know what an as-welded
HAZ hardness survey looks like without a temperbead or some other
hardness reducing technique.

What Dia and thickness pipe? Some customers require all pipe in sour
service to be post weld heat treated.

Hope this helps.

On Jul 21, 9:33 am, shiva <luvshiv2...@gmail.com> wrote:
> We are using API 5L X65 grade material for sour environment. With
> reference to our WPS we used (Ador electrodes) e 8010 for root and
> 8018 for hot fill pass.
> We took NDT and its okay. But after 1 month 4 weld joints crack. We
> checked the macro hardness for existing and cracked joint . There was
> a high hardness eg 351, 329 on root and in weld metal cap side 280
> above. Which is very high.
>
> Can you please tell me for this material what type of electrodes to be
> used? And why this occoured ?? And what may be possible reason for
> this occourance?
>
> Regards,
> Y.C.Shiva,
> QA/QC Engineer,
> +974 6166465
> Doha Qatar.

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