切削速度对切屑形态和加工表面微观形貌的影响

为了研究钛合金车削过程中切削速度和切屑形态特征对已加工表面微观形貌的影响。采用硬质合金涂层刀具车削钛合金TC4,研究了切削速度对切屑形态特征、已加工表面粗糙度和轮廓最大高度的影响规律,分析了切屑底部毛边形貌、已加工表面形貌与表面粗糙度三者之间的关系。结果表明:在切削速度40~120m/min时,切屑底边出现锯齿形毛边,且随切削速度增大锯齿越明显。切屑底部锯齿毛边的形成是造成已加工表面波峰损伤形成的主要原因。影响已加工表面粗糙度的微观形貌特征包括硬质颗粒、粘结现象和波峰损伤。因此,为了获得高质量的加工表面,加工参数选择时必须规避硬质颗粒和严重的粘结现象,并控制切屑底部毛边形态特征。

Effect of Cutting Speed on Chip Morphology and Machining Surface Micro-morophology

The purpose of this paper is to study the effect of cutting speed and chip morphology on the micro-morphology of the machined surface during turning of titanium alloy.Titanium alloy TC4 is turned by cemented carbide coated tools.The influence of cutting speed on chip morphology,surface roughness and maximum profile height is studied.The relationship between the bottom edge morphology of chips,the machined surface micro-morphology and surface roughness is analyzed.The results show that when the cutting speed is in the range of 40~120 m/min,the sawtooth appears on the bottom edge of the chip,and the sawtooth becomes more obvious with the increase of cutting speed.The micro-morphology characteristics affecting the machined surface roughness include hard particles,bonding phenomenon and wave crest damage.Therefore,in order to obtain high quality machined surface,the selection of processing parameters must avoid hard particles and serious bonding phenomena,and control the morphological characteristics of the bottom edges of chips.