High speed continuous turning of hardened steel with newly developed low content PCBN

In this study,newly developed low content PCBN was used to evaluate the cutting performance in high speed turning of hardened steel.Using new PCBN and commercially available PCBN tipped inserts under the same cutting condition,cutting performance with variable cutting speed,feed rate and depth of cuts on tools were measured by observation of flank and crater wear.Its microstructures were analyzed through SEM microscope,measurement of surface roughness on workpiece was also performed. According to cutting performance results,it is shown that new PCBN shows much longer tool life in high speed continuous turning than our conventional PCBN tools,with improved wear and chipping resistance.This result on the machinability of new PCBN for hardened steel will provide effective guidelines to manufacturing engineers,also provide useful economic machining solution for high speed continuous turning for hardened steel.

超高烧结压力对低含量、细粒度PCBN使用性能的影响

烧结压力是影响PCBN质量的关键因素,工业生产的压力通常小于6 GPa.通过设计特殊压机配件,优化组装结构,并采用高精度控温控压系统,在大于6 GPa条件下烧结低含量、细粒度PCBN.通过分析测试PCBN体积磨耗比、CBN层平整度和内部缺陷微观结构,并将成品刀具和元素六DCC500、住友电工BNX20进行对比车削试验,研究超高烧结压力对低含量、细粒度PCBN性能的影响.结果表明:超高烧结压力能够提高PCBN的耐磨性、平整度,促进CBN层和硬质合金层的扩散烧结.

烧结温度对高含量聚晶立方氮化硼组织与性能的影响

以立方氮化硼粉、钛粉、铝粉为原料,在高温(1400~1600℃)和超高压(6.5 GPa)条件下采用原位合成方法制备高含量聚晶立方氮化硼(PcBN),研究了烧结温度对PcBN力学性能、微观结构和切削性能的影响。结果表明:制备得到的PcBN均主要由BN、TiN、TiB_(2)、AlN等物相组成;随着烧结温度的升高,PcBN内部孔隙数量减少,密度增大,显微硬度和抗弯强度先升高后降低,PcBN刀具在切削行程长度达10 km后的后刀面磨损量先减小后增大。当烧结温度为1550℃时,PcBN的综合性能最佳,其抗弯强度和显微硬度最大,分别为969 MPa,40.7 GPa,后刀面磨损量最小,为0.26μm。