Achieving Low Temperature for Charpy Impacts
Achieving Low Temperature for Charpy Impacts
(OP)
I am trying to determine a way to achieve a testing temperature of -238F specifically for low temperature Charpy impact testing, on a weld procedure. This is a design temperature per a customer requirement.
Right now, my last option was just going with liquid nitrogen and testing at -320F but the weld metal was too brittle at the temperature and did not meet the impact requirements.
I am looking for any ideas of getting a sample bath closer to that -238F temperature, but not as cold as pure liquid nitrogen. Help?
Thanks!
Right now, my last option was just going with liquid nitrogen and testing at -320F but the weld metal was too brittle at the temperature and did not meet the impact requirements.
I am looking for any ideas of getting a sample bath closer to that -238F temperature, but not as cold as pure liquid nitrogen. Help?
Thanks!





RE: Achieving Low Temperature for Charpy Impacts
WDC-196T Charpy Impact Test Cooling Chamber
Otherwise, have a competent metallurgical lab perform the testing and certify the test results.
RE: Achieving Low Temperature for Charpy Impacts
RE: Achieving Low Temperature for Charpy Impacts
RE: Achieving Low Temperature for Charpy Impacts
I mean, the material would mostly recover it mechanical properties after it warms up, right?
RE: Achieving Low Temperature for Charpy Impacts
Yes, the impact properties will recover because of temperature. However, you are measuring the surface temperature and the sample needs to be tested at -238 deg F. Assuming the sample surface temperature reaches -238 deg F, the core temperature can be below this. Any competent materials/metallurgical testing lab does this testing routinely and has the equipment.
RE: Achieving Low Temperature for Charpy Impacts
From a pratical standpoint, however, I don't think it is going to help. That is, if you don't meet the requirements at -320F, you aren't likely to meet them at -238F. Assuming that the material exhibits a ductile/brittle transition with respect to temperature, either temperature is going to be on the lower shelf of the transition curve so the effect of temperature isn't going to be all that great; you will likely see more variation from the statistical nature of the results than you will see from the temperature difference. If the material does not exhibit transition behavior, even less. I guess, depending on what your material actually is and what results you are trying to achieve, it is possible that you might gain enough to meet the requirements, but I would doubt it.
rp
RE: Achieving Low Temperature for Charpy Impacts
rp
RE: Achieving Low Temperature for Charpy Impacts
RE: Achieving Low Temperature for Charpy Impacts