单颗CBN磨粒超声振动辅助磨削AISI 304材料去除机理

Material Removal Mechanism During Ultrasonic Vibration Assisted Grinding AISI 304 with Single CBN Grain

为了解释超声作用下磨粒切削材料的去除机理,对单粒磨削过程进行了分析,建立了未变形切削厚度和磨粒与试件的固定速度比(vs/vw)的数学模型.在AISI 304试件上进行了固定速度比的普通磨削(conventional grinding,CG)、切向超声振动辅助磨削(tangential ultrasonic vibration assisted grinding,TUVAG)以及径向超声振动辅助磨削(radial ultrasonic vibration assisted grinding,RUVAG)的单颗粒试验.结果表明,在固定速度比条件下,试件在CG与TUVAG作用下都是以塑性变形的形式去除,但超声辅助显著提高了材料去除率.试件在RUVAG作用下材料的去除方式与未变形切削最大厚度agmax的值息息相关.agmax小于0.8μm时,试件表现为脆性断裂的形式去除;之后随着agmax逐渐增大,试件转变为塑性变形的形式去除.

In order to explain the removal mechanism of abrasive cutting materials under ultrasonic action,the single grain grinding process was analyzed,and the mathematical model of undeformed cutting thickness and the fixed velocity ratio(vs/vw)of abrasive and workpiece was established.The single grain tests of conventional grinding(CG),tangential ultrasonic vibration assisted grinding(TUVAG)and radial ultrasonic vibration assisted grinding(RUVAG)with a fixed speed ratio were carried out on AISI 304 specimens.The results showed that the specimens are removed by plastic deformation under the action of CG and TUVAG at the fixed speed ratio,but the ultrasound significantly improves the material removal rate.The material removal method of the specimen under RUVAG was closely related to the value of the maximum undeformed cutting thickness agmax.When agmax is less than 0.8μm,the specimen was removed in the form of brittle fracture.After that,with the increase of agmax,the specimen was removed in the form of plastic deformation.