相変態を考慮した粘塑性構成式による低合金鋼鋳塊の熱応力及び残留応力の解析

概要

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It was found that the applied temperature range of ANAND's equations based on an internal variable theory, which describe the rate- and temperature-dependent constitutive relations, can be extended to lower temperatures less than a homologous temperature of 0.6 for a high carbon low alloy cast steel. Furthermore, phase transformation was introduced into these constitutive equations, thereby making it possible to represent stress-strain responses for all temperatures by a set of constitutive equations. To verify the above treatment under continuous cooling situation, including pearlitic transformation, a compression test with constant strain rate was performed. The result showed a reasonable agreement with the calculated stress-strain curve and the necessity to take into account 'transformation plasticity'. The main purpose of this paper is to develop a finite element method based on thus extended constitutive equations capable of calculating thermal stresses during an entire ingot casting process. The effects of transformation plasticity were also incorporated. The residual stresses measured at the surface of ingot have shown a reasonable agreement with the calculated values, verifying the method proposed. Although the analysis was done for this particular steel ingot, this method should be useful for analyzing other casting processes and materials.
社団法人日本鉄鋼協会の論文
1992-06-01