Brinell testing P 91

Date 09-11-2010 16:30

Can anyone tell me what the base metal temperature requirement is for Brinell testing . We have a P 91 plate, 1.500" thickness, that is cooling down from PWHT. How cool does it need to be before test can be performed? Also does anyone know if the D10 Committee has completed the guidelines for P91 and the other advanced chrome molys?
Thanks, Deb

By G.S.Crisi (****)

Date 09-11-2010 17:16 Edited 09-11-2010 17:21

Ambient temperature, but warm to the hand is OK.
It's a known fact that the higher the temperature, the lower the hardness.
Well, here in Sao Paulo, ambient temperature is never lower than 10 Celsius. I don't know what's the ambient temperature where you live. Maybe is minus 30 Celsius, in which case don't let it go down that low for your test. Chances are the material, if carbon steel, will be within the ductile - fragile transition range.
Giovanni S. Crisi
Sao Paulo - Brazil

By welderette (**)

Date 09-11-2010 17:25

Thanks so much! We are in Northern Arizona ambient today in the high country will be about 70 F.

By js55

Date 09-13-2010 12:39

Hardness will probably not change much once you achieve full martensitic transformation. In other words, below Mf temperature, the temp at which martensitic transormation ceases. And you have as much as you're going to get.
However, if you are going to test at hotter than ambient I would make this explicit in a procedure and reveal such to the end user, AND verify what I say is true. Don't just take my word for it.

By welderette (**)

Date 09-14-2010 12:05

Hey JS55, Thanks for the info. Ambient is good for me and I'll leave it there as far as the WPS is concerned, but it is good to know that there is some leaway. I have definitely been through the learning curve on this one.