Constitutive analysis in hot working
Constitutive analysis in hot working
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DOI：
10.1016/s0921-5093(01)01117-0
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发表时间：
2002-01-15
期刊：
影响因子：
6.4
通讯作者：
Ryan, ND
中科院分区：
文献类型：
--
作者：
McQueen, HJ;Ryan, ND
包含阿伦尼乌斯项的本构方程通常用于计算钢的热轧和锻造力。由于幂律和指数律分别在高应力和低应力下失去线性，应力和应变率的函数一般为双曲正弦函数。在奥氏体钢中，这些方程主要用于与动态再结晶（DRX）相关的峰值应力（应变），但也用于DRX成核和第一波完成的临界和稳态应力（应变）。由于溶质和细颗粒的存在提高了峰值应变，因此应力的提高比简单的应变硬化增加更大，从而导致合金钢中活化能的显著提高。相反，较大的碳化物、夹杂物或偏析物如果较硬，则可能由于粒子激发成核而降低峰值应变。由于应力和应变在峰值处呈线性关系，因此只需增加一个常数，就可以从本构数据中计算出流动曲线。最大孔道应力也可以由轧制规程多级扭转模拟中确定的sinh本构方程计算得到。将碳钢、微合金、工具钢和不锈钢与通常不表现DRX的铁素体钢进行比较。简要讨论了杂质和分散体对铝合金本构方程的影响。(C) 2002 Elsevier Science B.V.版权所有
Constitutive equations including an Arrhenius term have been commonly applied to steels with the objective of calculating hot rolling and forging forces. The function relating stress and strain rate is generally the hyperbolic-sine since the power and exponential laws lose linearity at high and low stresses, respectively. In austenitic steels, the equations have been used primarily for the peak stress (strain) associated with dynamic recrystallization (DRX) but also for the critical and steady state stresses (strains) for nucleation and first wave completion of DRX. Since the peak strain is raised by the presence of solutes and fine particles, the stress is raised more than by simple strain hardening increase, thus causing a marked rise in activation energy in alloy steels. In contrast, large carbides, inclusions or segregates, if hard, may lower the peak strain as a result of particle stimulated nucleation. Due to the linear relation between stress and strain at the peak, flow curves can be calculated from the constitutive data with only one additional constant. Maximum pass stresses can also be calculated from a sinh constitutive equation determined in multistage torsion simulations of rolling schedules. Comparison is made between carbon, micro-alloyed, tool and stainless steels and to ferritic steels which usually do not exhibit DRX. Parallels to the effects of impurities and dispersoids on the constitutive equations for Al alloys are briefly discussed. (C) 2002 Elsevier Science B.V. All rights reserved.