base material hardness testing requirement

[vesselguy]

In sour service,the typical practice is to confirm parent metal hardness before acceptance of plate or pipe product. MR0175/ISO15156 7.3.2 provides for this but does not specify where and frequency of hardness testing. For plate product (this would include ESW pipe product) my memory indicates only the surface hardness is checked at mill. I don't recall any through thickness requirements.

Question is: Are there any through thickness hardness requirements? If so, I would think it only apply to thickness > 3/4" thick product.

 

[metengr]

Well, if you think about it, surface hardness testing is really all you would need to perform because the outside surface will cool the fastest and subsurface will cool slower. In terms of maximum hardness, I would expect surface hardness testing is all you need. Frequency is a matter of what you decide and are will to pay.