CAJ | 학술논문

目的：研究了晶粒尺寸对冷成形过程中材料硬度变化的影响。方法通过不同的退火处理，获得了具有不同晶粒尺寸的材料。采用压缩试验、压痕试验和有限元模拟相结合的方法，研究了不同初始晶粒尺寸条件下材料硬度与等效应变的关系。结果初始晶粒尺寸d对材料初始硬度HV0、硬化系数K、硬化指数n有较大影响，随着晶粒尺寸的增大，它们呈减小趋势。同时提出了一个考虑晶粒尺寸影响的硬度预测模型，并进行了实验验证，硬度的预测值与测量值吻合较好。结论该模型能准确预测具有不同初始晶粒尺寸的材料在冷成形过程中的硬度分布。
목적：연구료정립척촌대랭성형과정중재료경도변화적영향。방법통과불동적퇴화처리，획득료구유불동정립척촌적재료。채용압축시험、압흔시험화유한원모의상결합적방법，연구료불동초시정립척촌조건하재료경도여등효응변적관계。결과초시정립척촌d대재료초시경도HV0、경화계수K、경화지수n유교대영향，수착정립척촌적증대，타문정감소추세。동시제출료일개고필정립척촌영향적경도예측모형，병진행료실험험증，경도적예측치여측량치문합교호。결론해모형능준학예측구유불동초시정립척촌적재료재랭성형과정중적경도분포。
The aim of this work was to study the influence of grain size on the material hardness during cold forming process. Different annealing treatments were performed to obtain materials with different grain sizes. And the relationship between material hardness and equivalent strain was investigated based on the combination of compression and indentation experiments and finite element simulations. The results showed that the initial hardness HV0, hardening coefficient K and hardening exponent n of the material were significantly influenced by the initial grain size, and all of them decreased with the increase of grain size. Meanwhile, a model considering the grain size effect was proposed to predict the hardness distri-bution in cold forgings, and the hardness values of the predicted results agreed well with the measured values. Based on the experiments, this model was validated to be capable to predict the hardness distribution in the cold forgings for materials with different initial grain sizes.