Abstract
Heat treatment is an important step for tool manufacture, but unavoidably generates dimensional distortion. This study investigated the continuous dimensional change and the anisotropic behavior of STD11 tool steel during austenitizing and tempering heat treatment especially using quenching dilatometer. Dilatometric results represented that the dimensional change along longitudinal direction was larger than that along transverse direction. Anisotropic phase transformation strain was produced in forged STD11 tool steel during heat treatment. Anisotropic dimensional change increased with increasing austenitizing temperature. After tempering, anisotropic distortion was partially reduced. FactSage thermodynamic equilibrium phase simulation and microstructural observation (FE-SEM, TEM showed that large (7-80 μm) elongated M7C3 carbides could be formed along rolling direction. The resolution of elongated carbides during austenitizing was found to be related with the change of martensite transformation temperature after heat treatment. Anisotropic size change of STD11 tool steel was mainly attributed to large elongated carbides produced during rolling process. Using dilatometric and metallographic examination, the possible mechanism of the anisotropic size change was also discussed.
| Original language | English |
|---|---|
| Pages (from-to) | 800-808 |
| Number of pages | 9 |
| Journal | Journal of Korean Institute of Metals and Materials |
| Volume | 46 |
| Issue number | 12 |
| State | Published - Dec 2008 |
| Externally published | Yes |
Keywords
- Anisotropy
- Austenitizing and tempering
- Quenching dilatometer
- STD11
- Tool steel