Hi ,
I've made an ECAP die out of H13 tool steel . After doing a hardening heat treatment in 1000C and quenching in air , i have a thin film of oxidated steel on it . It makes my surface very rough .
Why this happened ? And how can i handel this issue ?
It has happend due to presence of oxygen in air that You have use. That is certain. During the oxidation of H13, depending on oxygen partial pressure and temperature, You can obtain either compact Fe2O3 oxide layer, when high oxyhen partial pressure and lower temperature (below 600°C) are present, and Fe2O3 on surface, Fe3O4 in the middle and FeCr2O4 and other spinnels (FeV2O4, Fe2SiO4) adjacent to metal, when lower oxygen partial pressure and higher temperatures are present. In Your case, You have probably got Fe2O3, Fe3O4 + spinel phases due to exposing of H13 at 1000°C in air (conditions for faster growth of oxides phases). Try to analyze the surface with X-ray Diffraction if it means to You. Then You will know. If that is the case, then try to increase oxygen partial pressure to avoid fast oxidation or just simply use pure nitrogen or argon instead of air for quenching purposes. Play around if You can. Best regards, BG.
I agree with everything Mr. Bojan said.
I had a similar experience on an SAE 4340 die that I built recently.
About on how to handle the issue, I would recommend you to use sandpaper to remove the excess of oxides on the exterior parts of the die.
However, on the contact parts of the die, sanding may not be enough.
In the contact parts, I suggest that you try rectifying the surfaces as flat as possible.
If you don't have the tools for it at hand, you can hire a machining company for doing it for you.
Good luck!
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials
- Inorganic Materials
- Metals
- Alloys
- Steel