As per applicable NACE MR0103, the hardness limit for the material you mentioned, A302 Gr. B (P. No. 3) the maximum hardness limit is 225 HBW and the manufacturer has to comply with this if you specified that all NACE requirement has to be met. Regards, Ashfaq http://thepetrostreet.com >Thanks all >our problem is this: >we have sour service in some equipments of our unit. >we have to use SA 302 Gr.B for some part of equipments, but >steel manufacturer told us that he can't mention NACE >conformity in material certificate because of high strength >material. (he agreed that NACE requirements will be >considered but he insist that he can't mention it in >material certificate). >I can't understand it , I think when all of NACE >requirements are applied then there is no reason to >disagreed with NACE certificate!