低周疲劳精密下料新工艺及试验研究  

Experimental Study on New Low Cycle Fatigue Precision Cropping Process

作　　者：赵仁峰[1] 赵升吨[1] 钟斌[1] 郭桐[1] 

机构地区：[1]西安交通大学机械工程学院,西安710049

出　　处：《机械工程学报》2012年第24期38-43,共6页Journal of Mechanical Engineering

基　　金：国家自然科学基金资助项目(51175413)

摘　　要：传统的金属棒料下料工艺存在着材料利用率低、能耗高、生产效率低以及下料断面质量差等问题。采用一种新的下料工艺-周向加载低周疲劳精密下料技术,利用V形槽的应力集中效应,促使棒料V形槽底尖端处疲劳裂纹的萌生及疲劳裂纹的快速扩展。描述周向加载低周疲劳精密下料机的工作原理。给出在低周疲劳下棒料V形槽根部裂纹是否起裂的判据。采用两种控制曲线对5种材料(20钢、H59、45钢、20Cr和LY12)的棒料进行试验研究,实现加速棒料裂纹的产生、扩展并获得良好的棒料断面质量。试验结果表明,V形槽的应力集中效应可以有效地减小棒料下料过程中的平均应力,在不断增加打击位移的同时减小冲击频率可以保证棒料裂纹的稳定扩展和断裂。The traditional cropping processes have some disadvantages,such as poor surface quality,low yield,waste of materials and high energy-consumption.The precision cropping process with circumferential force low cycle fatigue,which is a new type of precision cropping process method,is studied.According to the stress concentration effect of a V-shape notch,the fatigue crack on the tip of the V-shape notch is prompted to initiate and extend.The precision cropping machine＇s working principle is described.The criterion that the crack on the root of V-shape notch initiate or not under the effect of low cycle fatigue is provided.The materials which include 0.2%C steel,H59 copper,0.45%C steel,20Cr steel and LY12 aluminum are studied under two control curves.Accelerating the initiation and extension of crack and the good cross section of the metal bar are obtained.The results show that the mean stress of the metal bar in the cropping process can be effectively reduced because of the V-shape notch＇s stress concentration.The metal bar＇s stable crack growth and fracture can be got when increasing impact displacement constantly at the same time reducing the impact frequency in the cropping process.

关 键 词：精密下料 应力集中 低周疲劳 裂纹 

分 类 号：TG316[金属学及工艺—金属压力加工]