NACE MR0175 - Production Weld Hardness Test

[Weko]

My Client intend to have Production Weld Hardness test for our "NACE" categorize material. We are in a Gas Plant processing (AGRU & SRU).

In NACE MR0175. The weld deposite value for WPS/PQR is 250 HV. However HV can not be used for production weld, since it needs to be destructive test. While portable hardness test is usually brinell.

If we use ASTM E140, we will have 250 HV converted into 238 HB. But the problem is we have some discussion about that brinel identation is bigger than vickers.

Some suggest also to use NACE MR0103 weld deposit value of 200 HB (but this is a different NACE system)

Anybody could advice, how is the proper way to do Production weld Hardness Test for NACE MR0175?

Regards,
Weko A

 

[EdStainless]

What some people do is to use their weld qualification coupons for hardness comparison also.
They test the same coupon with each type of tester that they plan on using.
The hardness testing should have been part of your qualification, if you knew that you were going to use Brinell on the actual welds then you should have used it in qualification.

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P.E. Metallurgy, Plymouth Tube

 

[SJones]

The best way is to follow the individual hardness testing standards to the extent that the achieved results have acceptable reliability. Annex B of ISO 17945 provides a good treatise on portable hardness testing. The ISO 17945/MR0103 hardness acceptance criteria have been "factored" to account for the issues associated with using portable hardness testing equipment. Thus, it is the same "NACE system" with a perceived safety factor.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.