具有非线性表面换热系数半圆柱薄壳在快速冷却过程中的热分析

Thermal Analysis on a Half Cylinder Shell of 42C Rmo Steel With Non-Linear Surface Heat-Transfer Coefficients During Rapid Cooling

用实验和数值计算相结合的方法 ,得到半圆柱壳体快速冷却过程中内外表面的非线性表面换热系数。在此基础上 ,用有限单元法对半圆柱壳体的热应力和变形进行了分析。在数值计算中 ,模拟钢的CCT图 ,计算了奥氏体、珠光体、贝氏体和马氏体的体积百分比 ,并将热物理性质和力学性能处理为相变体积百分比和温度的函数。所得结果表明 ,在半圆柱壳体快速冷却过程中的热应力和变形计算中 ,有必要考虑非线性表面换热系数。

Non linear surface heat transfer coefficient is obtained by experimental and numerical methods and the CCT diagram is simulated by mathematical transformation. The volume fractions of constituent of austenite, perisite, bainte and martensite in continuous cooling are calculated, temperature field with non linear surface heat transfer coefficients is calculated using finite element technique. In numerical calculation, different values of the non linear surface heat transfer coefficients between inner surface and outside surface of the shell are taken account of and the thermal physical properties are treated as the functions of temperature. The experimental results of temperature field coincide with numeral solutions. Finally, the thermal stress is calculated by finite element method.