Carbon content increased in heat treat?
Carbon content increased in heat treat?
(OP)
Hi all!
I have to admit the question I am about to ask is probably a seemingly dumb question in the metallurgy engineering world. I do have some explanations for it but would like to get some feedback on those if possible. I am not a metallurgist so I am not familiar of the details in regards to heat treating steel.
Question: There is no way that carbon content can be "added" to the material during heat treat is that correct? The material in question is 440C stainless.
Reason for the question:
Carbon content was 1.01% when the material is in its raw state (none heat treated drawn wire) but increased to 1.1% post-heat treat. Now the material tested is not exactly the same (as in we didn't take the same batch before heat treat for testing, process it and then perform another test) but they did come from the same heat load.
My thoughts on this:
1) Is it possible that carbon is introduced to material in the furnace during heat treat? We make balls and post-heat treat they get grinded down so I believe any surface carb may have been removed already and would probably not alter the material in the core.
2) Test method in obtaining chemical composition may be different each time?
3) Because we purchase bulk wire, is it possible that different parts of the coils of wire may have slightly different carbon content?
Again, I'm not an expert in this so I hope someone can help me demystify the increase in carbon content.
Thanks!
I have to admit the question I am about to ask is probably a seemingly dumb question in the metallurgy engineering world. I do have some explanations for it but would like to get some feedback on those if possible. I am not a metallurgist so I am not familiar of the details in regards to heat treating steel.
Question: There is no way that carbon content can be "added" to the material during heat treat is that correct? The material in question is 440C stainless.
Reason for the question:
Carbon content was 1.01% when the material is in its raw state (none heat treated drawn wire) but increased to 1.1% post-heat treat. Now the material tested is not exactly the same (as in we didn't take the same batch before heat treat for testing, process it and then perform another test) but they did come from the same heat load.
My thoughts on this:
1) Is it possible that carbon is introduced to material in the furnace during heat treat? We make balls and post-heat treat they get grinded down so I believe any surface carb may have been removed already and would probably not alter the material in the core.
2) Test method in obtaining chemical composition may be different each time?
3) Because we purchase bulk wire, is it possible that different parts of the coils of wire may have slightly different carbon content?
Again, I'm not an expert in this so I hope someone can help me demystify the increase in carbon content.
Thanks!





RE: Carbon content increased in heat treat?
Maui
RE: Carbon content increased in heat treat?
RE: Carbon content increased in heat treat?
RE: Carbon content increased in heat treat?
Carbon can be either added or removed from the surface of a steel alloy during a heat treatment. It depends upon the alloy, temperature, and atmosphere present. 440C is not a carburizing (case hardening) alloy, it is a thru hardening alloy. So there's no reason it should have gone thru a carburizing process. Standard 440C should have a carbon content between 0.95% and 1.20%
Carburizing is the intentional introduction of carbon into the surface of a steel alloy part in order to permit that surface to be case hardened.
Decarburization is a condition (usually unintentional) that can result when a steel alloy part is heated above a certain temperature in an atmosphere that has oxygen present. The surface of the part can lose carbon thru oxidation, resulting in a surface condition that is metallurgically inferior. This surface must usually be removed after heat treat.
Hope that helps.
Terry
RE: Carbon content increased in heat treat?
RE: Carbon content increased in heat treat?
RE: Carbon content increased in heat treat?