STD11 공구강의 열처리 치수변화 이방성에 미치는 제조 조건의 영향

• Published in: 대한금속·재료학회지, 50(1) Vol. 50; no. 1; pp. 13 - 22
• Main Authors: 홍기정, Ki Jung Hong, 송진화, Jin Hwa Song, 정인상, In Sang Chung
• Format: Journal Article
• Language: Korean
• Published: 대한금속재료학회 20.01.2012; 대한금속·재료학회
• Subjects: anisotropy; heat treatment; STD11; tool steel; 재료공학
• ISSN: 1738-8228; 2288-8241

Forged and flat-bar rolled STD11 tool steel shows anisotropic dimensional change during heat treatment. The dimensional change in the rolling direction is larger than that in the transverse direction. The cause of the anisotropic dimensional change is that the steel is anisotropic in composition, microstructure and other properties. The decrease of anisotropic distortion in tool steel is important for making better precision cold working dies. In this study, the effect of ingot weight and hot rolling reduction ratio on the anisotropic dimensional change of STD11 during heat treatment has been studied. Dimensional change was evaluated by simulating a real heat treatment process, including gas quenching and tempering. Experimental results showed that all the rolled flat-bar products had anisotropic distortion to some degree, but the anisotropic distortion was reduced as hot rolling ratio increased. Ingot weight had a little effect on anisotropic distortion. Microstructural observation showed that the anisotropic dimensional change of STD11 tool steel was closely related to the amount, shape and distribution of coarse carbides.