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为了合理制定35MnB钢制件热成形工艺参数,在790~1190℃温度范围内,应变速率为0.01~10 s~(-1)及总压缩变形量(真实应变)为0.6的试验条件下,采用Gleeble-1500D热模拟试验机对35MnB钢进行热压缩变形试验,研究其高温变形行为。结果表明:流变应力随着温度的升高而减小,随着应变速率的增大而增大。同一应变速率下,随着变形温度的升高应力峰值向左移动,应力-应变曲线整体下移;同一变形温度下,应变速率越大,应力峰值越高,相应的应变量也越大。采用含有变形温度(T)和变形激活能(Q)的Arrhenius equation方程的双曲正弦模型,构建了35MnB钢在高温下流变应力与应变速率的本构方程。并验证了所构建本构方程的准确性,计算结果显示预测应力峰值与试验应力峰值吻合较好。通过采用本文所构建的35MnB钢本构方程对大型液压装载机锻造摇臂成形过程进行模拟,结果证明本文所构建的本构方程可以应用于35MnB钢制件高温成形模拟过程,并为实际生产做指导。
In order to reasonably set the parameters of the hot forming process of 35MnB steel parts, under the test conditions of strain rate of 0.01 ~ 10 s ~ (-1) and total compressive deformation (true strain) of 0.6 in the temperature range of 790 ~ 1190 ℃, Gleeble-1500D thermal simulation testing machine for 35MnB steel hot compression deformation test to study the high temperature deformation behavior. The results show that the flow stress decreases with the increase of temperature and increases with the increase of strain rate. Under the same strain rate, the stress peak shifts to the left with the deformation temperature going down, and the stress-strain curve moves downwards. Under the same deformation temperature, the larger the strain rate is, the higher the stress peak is and the larger the corresponding strain is. Constitutive equations of the flow stress and strain rate of 35MnB steel at high temperature were constructed by using the hyperbolic sine model of Arrhenius equation with deformation temperature (T) and deformation activation energy (Q). The accuracy of the constructed constitutive equation is also verified. The calculated results show that the predicted stress peaks agree well with the experimental stress peaks. By using the 35MnB steel constitutive equation constructed in this paper, the forming process of the forging rocker arm of a large hydraulic loader is simulated. The results show that the constitutive equation constructed in this paper can be applied to the high temperature forming simulation of 35MnB steel parts, guide.