After final PWHT, the hardness of the deposited weld metal and heat affected zone (HAZ) shall be examined. Hardness values shall not exceed 200 BHN. Heat treatment shall be performed, if required to reduce hardness to the specified level, subject to review and approval by WorleyParsons Canada.
On drums, hardness shall be measured one on each of the following welded areas:
a. Circumferential
b. Longitudinal
c. Nozzle
d. Stub
e. Attachment
Hardness test shall be made with a Brinell Testing machine or a portable hardness tester such as a Telebrineller using a 10 mm (3/8") ball.
Submerged arc weld, SAW shall be tested for hardness on the weld and on the HAZ. The values shall not exceed 200 BHN.
Where required value of BHN is not achieved, the fabricator shall perform a retest without any heat treatment whatsoever. If this second test fails to meet the BHN requirement, heat treatment shall be repeated. Methods and procedures for anticipated second heat treatment shall be pre-approved by WorleyParsons Canada.