JIS SKD61の焼入れ変形の数値解析による予測

概要

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The strongly commercial interests have been focused on avoid distortion and attain higher toughness of quenched JIS SKD61 die block. FE (Finite Element) analyses before practical trials that can visualize local distribution of temperature or stress are available to complete these requests. In order to establish the basics of simulation technique, stress-strain behavior is derived from tensile tests and also boundary condition data is generated through quenching tests in compressed N2 gas. Its obvious that the elastic/plastic boundary stress which to be treated as yield point in FE analyses is from 35 to 80 % for 0.2 % proof stress. And the influence of gas pressure P on heat transfer coefficient h is defined for material surface temperature. Given h is approximately 250 W/m2/K for P equals to 4700 torr. Then the validity of database is verified on quenching of die-block-like two types of 4 kg work-pieces. Predicted transformation temperature is agreed well with that in experiments. And also the tendency of change in work-piece size is represented by FE analyses. Moreover the difference of distortion between shapes of work-pieces during quenching is shown. These results suggest that the recommended process could be designed for each die shape and its expected through numerical simulation.
電気製鋼研究会の論文