Lyrl
Materials
- Jan 29, 2015
- 67
We are a commercial heat treater. One of our customers occasionally has us anneal A890-CE3MN material. The parts have a relatively thick core (2-6"), relatively thin webbing (1/4") out to a rim with a thickness of around 1.5". Our process is heat to 2050°F, soak for a few hours (varies by section size), drop to 1910°F for 15-30 minutes, then high-pressure gas quench.
Our customer frequently finds cracks in most or all of the parts after the anneal. Sometimes they have found cracks before we ever touched the parts, too, so I'm not sure how much of the cracking is from the heat treatment and how much is just a design issue. They've also occasionally had problems with the tensile test failing. We haven't properly documented all our process history vs. their results, so I'm not sure if the tensile failures resulted from lower quench pressures that we tried or from slow heat-up rates that we tried (after some recent reading I realized the slow heat-up rate may have allowed detrimental microstructures to form).
As the heat treater, are there any changes to our process we can make to minimize the crack risk without excessively harming the tensile results? Any other non-heat treat advice we could pass on to our customer (a small cast house)?
Our customer frequently finds cracks in most or all of the parts after the anneal. Sometimes they have found cracks before we ever touched the parts, too, so I'm not sure how much of the cracking is from the heat treatment and how much is just a design issue. They've also occasionally had problems with the tensile test failing. We haven't properly documented all our process history vs. their results, so I'm not sure if the tensile failures resulted from lower quench pressures that we tried or from slow heat-up rates that we tried (after some recent reading I realized the slow heat-up rate may have allowed detrimental microstructures to form).
As the heat treater, are there any changes to our process we can make to minimize the crack risk without excessively harming the tensile results? Any other non-heat treat advice we could pass on to our customer (a small cast house)?
