| Title |
Microstructural Changes and Variations of Hot Deformation Stability with Homogenization Treatment of 1Cr-1.25Mo-0.25V Steel before Hot Forging |
| Authors |
권거영(Keo Young Kwon); 나영상(Young Sang Na); 서성문(Seong Moon Seo); 양재규(Jea Kyu Yang); 김양도(Yang Do Kim) |
| DOI |
https://doi.org/10.3365/KJMM.2013.51.12.883 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
metals; homogenization treatment; hot working; microstructure; compression test |
| Abstract |
In order to investigate the effects of homogenization treatment on microstructural change and high temperature deformation stability, a series of hot compression tests and homogenization treatment were conducted for as-cast and upset-forged 1Cr-1.25Mo-0.25V steels. Microstructural inhomogeneity like dendritic morphology and elemental segregation in as-cast steel was homogenized after 10 hours-holding at 1200 ℃, followed by the rapid grain coarsening up to about 700 μm after 20 hours-holding. However, upset- forged steel showed rapid grain coarsening even in the early stage of high temperature holding at 1200 ℃. Compression tests for the 1Cr-1.25Mo-0.25V steels showed that flow stresses of as-cast 1Cr-1.25Mo-0.25V steel were higher than those of the upset-forged at temperatures lower than 1000 ℃. By analyzing the compression test results based on a dynamic materials model, we concluded that the microstructural inhomogeneity diminished hot deformation stability of the as-cast 1Cr-1.25Mo-0.25V steel. It is clear that the microstructural homogenization of as-solidified steel prior to upset forging is essential for improving the hot deformation stability and soundness of hot forgings. |