Hardness test results
Hardness test results
(OP)
Guys,
we just ran some production test plates as part of our current welding project.
On one of the samples the hardness results are a little high. We have one reading (out of 45) which is 378Hv. Our max allowable is 350Hv. We are working to DNV C401.
My query; There were 3 readings taken in this particular location (weld HAZ), the average of the 3 readings is 314Hv. I have done hardness testing down the years, and as it is quite a subjective test, we have always worked on average readings, and not individual readings.
Does my test plate pass the test or not?
regards
Declan
we just ran some production test plates as part of our current welding project.
On one of the samples the hardness results are a little high. We have one reading (out of 45) which is 378Hv. Our max allowable is 350Hv. We are working to DNV C401.
My query; There were 3 readings taken in this particular location (weld HAZ), the average of the 3 readings is 314Hv. I have done hardness testing down the years, and as it is quite a subjective test, we have always worked on average readings, and not individual readings.
Does my test plate pass the test or not?
regards
Declan





RE: Hardness test results
RE: Hardness test results
RE: Hardness test results
RE: Hardness test results
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Hardness test results
RE: Hardness test results
RE: Hardness test results
RE: Hardness test results
RE: Hardness test results
RE: Hardness test results
378 over 350 is a significant miss. I assume you are using Vickers with a 10kg indentation load. Hopefully you are not running into the dreaded and much-debated local brittle zones (LBZ).
My philosophy on HAZ testing is that you report the hardest result, unless it is clearly an outlier. Maximum hardness often lies near the plate surface, where it matters most.
I have seen many sloppy, metallurgically ignorant lab techs (and some engineers) get weld hardness testing criminally wrong. (I'm not suggesting you are in that group.)
RE: Hardness test results
RE: Hardness test results
If you are doing field hardness using a MIC 10 I would consider looking into ASTM A1038 at the proper calibration requirements for this equipment. Using an incorrect calibration standard can drastically change the results