【作者】 赵勇；

【导师】 张学成； 侯军辉；

【作者基本信息】 吉林大学 ， 机械工程， 2006， 硕士

【摘要】 高速切削是近年来金属切削研究的热点之一,也是未来金属切削的发展方向。锯齿形切屑是金属高速切削变形的一种主要形式,而人们普遍认为绝热剪切是产生锯齿形切屑的主要原因,因此研究绝热剪切以及锯齿形切屑的性质对于从理论上认识和掌握高速切削机理起着重要的作用。本文通过对几种典型材料高速切削中锯齿形切屑的实验研究可以得出以下结论:锯齿形切屑的绝热剪切步距随着切削速度的增加而增大,随着进给量的增加而增大,与切削深度的变化关系不大。从切屑塑性变形角度分析得出切削力随切削速度的增加而减小。锯齿形切屑的变形系数随着切削速度的增加而减小,随着进给量的增加而减小。从切屑塑性变形角度分析得出切屑的变形系数与绝热剪切步距的对应关系。通过在扫描电镜下的观察得出绝热剪切带的微观形貌。锯齿形切屑的绝热剪切带是一种致密的挤压滑移变形组织。与其相临的金属晶粒有的镶嵌在其边缘,有的一部分参与到绝热剪切带的内部。而与其相距稍远的金相组织基本未发生明显变形。通过退火实验发现绝热剪切带在一定的退火工艺后自行消失,从而得出绝热剪切带是一种塑性变形组织。更多还原

【Abstract】 The high-speed cutting is one studied central point of metal cutting recently. It isthe direction of developing metal cutting in the future too. The adiabatic shear isresearched always when it was found in 1940’s. Being material plastic deformphenomenon, it widely exists in metal cutting, high-speed forming, run through armorand surface friction.The saw-tooth chip is a main form in metal high-speed cutting deform. It isbelieved that the main reason of producing saw-tooth chip is the adiabatic shear. So itis important to study the properties of adiabatic shear and saw-tooth chip. They willhelp us to understand the high-speed cutting mechanism.Through the research of the saw-tooth chip following conclusions are obtained:Increasing the cutting speed or the feed will decrease the adjacent tooth distanceof the saw-tooth chip. But the cutting depth will not affect the distance. So increasethe cutting speed will result in the decrease of the chip plastic deform and the cuttingforce.Increasing the cutting speed or the feed will decrease the deform coefficient of the saw-tooth chip too. There arecorresponding relations between the deform coefficient and the adjacent tooth distance in the saw-tooth chip.The microcosmic form of the ASB is researched through the SEM. The ASB inthe saw-tooth chip is a kind of fine, close and extruding slide deform organization.The metal crystalline grains which adjacent the ASB inlay in the ASB or change into apart of it. While the grains which far away from the ASB haven’t obvious deform.The ASB will disappear by itself in the annealing experiment. So the ASB is akind of plastic deform organization.更多还原