铜对4Cr16Mo塑料模具钢切削性能的影响

Effect of Copper on Machinability of 4Cr16Mo Plastic Mold Steel

将4Cr16MoCu、4Cr16Mo和SDP136钢在1030℃保温4 h,冷却至室温后回火两次,第一次为540℃×4 h,4Cr16MoCu钢的第二次回火工艺为590℃×3 h,4Cr16Mo和SDP136钢为565℃×3 h,使其硬度达到35~36 HRC。采用扫描电子显微镜检测钢的显微组织,采用数控车床进行切削性能试验。分别采用SY-3F型应变式三维测力传感器、红外测温仪、TR200粗糙度测量仪和超景深显微镜测定切削力、刀尖温度、工件粗糙度和磨损刀具的形貌。结果表明:在相同的切削条件下,铜的添加能延长刀具的使用寿命;切削4Cr16MoCu钢的刀具温度比切削4Cr16Mo钢的刀具温度低50℃,切削试验的前、中期4Cr16Mo钢的切削力比4Cr16MoCu钢大43~94 N,但后期4Cr16MoCu钢的切削力上升至839 N,比SDP136钢大211 N。

4Cr16MoCu,4Cr16Mo and SDP136 steels were held at 1030℃for 4 h and cooled to room temperature,and then were twice tempered as follows:the first tempering at 540℃for 4 h,and the second tempering at 590℃for 3 h for 4Cr16MoCu steel and at 565℃for 3 h for 4Cr16Mo and SDP136 steels,to cause them to reach hardness of 35 to 36 HRC.The microstructures of the steels were surveyed by a scanning electron microscope.The machinability of the steels was tested by numerically controlled lathe.Cutting force,tool tip temperature,workpiece roughness and pattern of the worn cutter were measured by SY-3F strain type three-dimensional force sensor,infrared thermodetector,TR200 roughness measuring instrument and ultra-depth of field microscope,respectively.The results showed that(a)under the same cutting conditions,the addition of copper was likely to prolong the service life of the tool;(b)temperature of the tool cutting 4Cr16MoCu steel was 50℃lower than that of tool cutting 4Cr16Mo steel,and the cutting force of 4Cr16Mo steel was 43 to 94 N higher than that of 4Cr16MoCu steel at earlier and middle stages of the cutting test,however,the cutting force of 4Cr16MoCu steel rose to 839 N at later stage of the cutting test,which was 211 N higher than that of SDP136 steel.