1Cr-1.25Mo-0.25V 합금강의 단조 전 균질화 처리에 따른 미세조직 변화 및 고온변형 안정성 평가 (Microstructural Changes and Variations of Hot Deformation Stability with Homogenization Treatment of 1Cr-1.25Mo-0.25V Steel before Hot Forging)

서지정보

· 발행기관 : 대한금속·재료학회
· 수록지 정보 : 대한금속·재료학회지 / 51권 / 12호 / 883 ~ 892페이지
· 저자명 : 권거영, 나영상, 서성문, 양재규, 김양도

초록

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, upsetforged 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.

영어초록

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, upsetforged 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.

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