Brinell hardness reliability 1

[ryanethan]

Are Brinell hardness values concrete proof that a weld joint is mechinally safe after PWHT. For example P1 to P5A material using E9018-B3 with a hardness of 138 parent material,165 HAZ, 207 weld material, 135 HAZ, and 131 parent material. Are these hardness values for this type of joint acceptable?

 

[metengr]

ryanethan;
Portable hardness testing can be used as a process control check, nothing more. If the hardness test results are within an acceptable range for the service duty of the component (or based on client's specification requirements) along with other process checks (review of PWHT temp range and time charts, etc), the hardness would verify PWHT was performed.

Mechnically safe???? You have more than just PWHT requirements and hardness to deal with, you can have NDT requirements, which are equally as important regarding performance of a weld joint in service.

The hardness you mention are acceptable to what I would expect for the given dissimilar weld joint welded with E9018 B3.

 

[ryanethan]

The dissimilar weld in question deals with B31.1 and is piping on the external of a boiler with MAWP 2500psi @354 degrees celcius.

 

[stanweld]

The hardness values obtained are not atypical for the joint described after PWHT. The P5A material appears to have been in the annealed condition. What was the temperature and hold time of the PWHT?

 

[weldtek]

Did you or some other knowledgeable person review the hardness test procedure? Technique, bar hardness, and reporting are all critical features of the process.

 

[HouseHark]

I find the hammer blow Poldi technique quite accurate if you can see the indentation and know what you are doing, I know some companies who struggle to get consistent readings with top of the range portable hardness testers.

I think if the reading varies 1/10 times on a calibration block it is not calibrated. Our electronic one doesn't have that , especially on a rougher surface.

All that is slightly off topic but answer is given, no way is brinell hardness concrete proof. Just more information to be used in your evaluation.

Not all specs even call for a hardness check PWHT?