马车螺栓镦锻成形微观组织有限元模拟  

Finite element simulation of microstructure in upseting of carriage bolt

作　　者：丛兵兵 杜以常 张弘斌[1] 孔明 秦升学[1] 刘杰[1] CONG Bing-bing;DU Yi-chang;ZHANG Hong-bin;KONG Ming;QIN Sheng-xue;LIU Jie(School of Mechanical and Electronic Engineering,Shandong University of Science and Technology,Qingdao 266400,China;Shandong Tengda Fastening Technology,Zaozhuang 277500,China)

机构地区：[1]山东科技大学机械电子工程学院,山东青岛266400 [2]山东腾达紧固科技股份有限公司,山东枣庄277500

出　　处：《塑性工程学报》2023年第3期175-182,共8页Journal of Plasticity Engineering

基　　金：山东省自然科学基金资助项目(ZR2021ME234)。

摘　　要：对304不锈钢的流变应力数据进行处理,获得了304不锈钢在改进的L-J位错密度模型中的应变软化参数、加工硬化参数和自扩散激活能等表征参数,建立了304不锈钢L-J位错密度模型,进而采用有限元方法对马车螺栓镦锻成形过程中微观组织变化开展有限元模拟,并将模拟结果与金相实验得到的微观组织进行对比分析。结果显示,304不锈钢马车螺栓成形过程中,螺栓头部晶粒被压扁、拉长明显,方颈部位晶粒也有一定程度的细化,而杆部晶粒变化不明显;螺栓成形后,6个样品区的应变分别为2.03、2.32、0.48、0.64、0.03和0.05,其中,螺栓头部内外侧平均晶粒尺寸分别减小了约31.3%、33.5%,而硬度分别提高了约35.9%、40.8%,方颈部位内外侧平均晶粒尺寸分别减小了约23.5%、26.2%,而硬度分别提高了约24.5%、30.2%,杆部外侧平均晶粒尺寸略微减小,硬度略微增加;模拟的平均晶粒尺寸比实验的平均晶粒尺寸要小,晶粒分布更密集,但误差水平大体一致。The flow stress data of 304 stainless steel was processed,and the characterization parameters such as strain softening parameters,work hardening parameters and self-diffusion activation energy of 304 stainless steel in the improved L-J dislocation density model were obtained,and the L-J dislocation density model of 304 stainless steel was established,and then the finite element method was used to simulate of the microstructure changes of carriage bolt during upsetting forging process,and the simulation results was compared with the microstructure obtained by metallographic experiments.The results show that during the forming process of 304 stainless steel carriage bolts,the grains at the head of the bolts are flattened and elongated obviously,and the grains at the square neck are also refined to a certain extent,while the grains at the rod have no obvious change.After the bolt is formed,the strains in the six sample areas are 2.03,2.32,0.48,0.64,0.03 and 0.05,respectively.The average grain size inside and outside the bolt head is reduced by about 31.3%and 33.5%,while the hardness is increased y about 35.9%and 40.8%,respectively.The average grain size inside and outside the square neck area is reduced by about 23.5%and 26.2%,while the hardness is increased by about 24.5%and 30.2%,respectively.The average grain size outside the rod is slightly reduced,and the hardness is slightly increased.The simulated average grain size is smaller than the experimental average grain size and the grain distribution is denser,but the error level is roughly the same.

关 键 词：304不锈钢 马车螺栓 L-J位错密度模型 微观组织模拟 

分 类 号：TG316.3[金属学及工艺—金属压力加工]