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http://dx.doi.org/10.3365/KJMM.2012.50.1.013

Effect of Manufacturing Conditions on the Anisotropic Dimensional Change of STD11 Tool Steel during Heat Treatment  

Hong, Ki-Jung (Analysis & Assessment Center, RIST)
Song, Jin-Hwa (POSCO Technical Research Laboratories, POSCO)
Chung, In-Sang (School of Materials Science and Engineering, Kyungpook National University)
Publication Information
Korean Journal of Metals and Materials / v.50, no.1, 2012 , pp. 13-22 More about this Journal
Abstract
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.
Keywords
anisotropy; STD11; tool steel; heat treatment;
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