Plasticity of Steels during Martensite Transformation and Quench Cracking in Heat Treatment of Steel
1973 Volume 59 Issue 2 Pages 308-312
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1973 Volume 59 Issue 2 Pages 308-312
By applying an impact tensile load to steels at various stages of the transformation from austenite to martensite, the plasticities of low alloy steels during quenching determined in terms of the reduction of area. The results obtained are as follows.
1. The plasticity of the steels decreased rapidly as the martensitic transformation proceeded, and recovered somewhat after the completion of transformation, thus exhibiting a minimum.
2. The mini-num plasticity depended on the carbon content of the steel, decreasing with increasing the carbon content and becoming nil at 0.47%C.
3. By examining those plasticity values in regard to the theoretically evaluated internal quench stress values, the quench cracking tendency of a steel could be anticipated, and the safety limit for water quenching could be established. This was successfully applied to medium carbon low alloy steels of various sizes and weights.
