摘要：使用PCBN刀具对5种不同淬硬状态（40±1HRC，45±1HRC，50±1HRC，55±1HRC，60±1HRC）Cr12MoV模具钢进行干式硬态车削试验，揭示了切削速度、走刀量、切削深度、工件硬度对已加工表面粗糙度及三维形貌的影响规律及机理。研究结果表明：与车削硬度为40±1HRC、45±1HRC、60±1HRC的工件相比，以v=50，250，450，650，850m/min车削硬度为50±1HRC、55±1HRC的工件时，切削速度对表面粗糙度的影响较为显著，最小表面粗糙度可达0.569μm。车削60±1HRC的工件时，随切削深度的增大，表面粗糙度值逐渐减小，当ap>015mm时，Ra<1.00μm；而走刀量的影响规律与其反之，当f<0.15mm时，Ra<1.00μm。已加工三维形貌表明，车削较软的工件时，由于刀具切削刃后刀面对被高温软化的已加工表面的二次伤害使得三维形貌突起的棱脊模糊不清；车削较硬的工件时，刀-工界面硬质颗粒的犁耕效应及后刀面的小沟槽复制效应，使已加工表面产生小沟槽。

关键词：干式硬态车削；淬硬钢；表面粗糙度；三维形貌

中图分类号：TG51；TH161.1文献标志码：ADOI：10.3969/j.issn.1000-7008.2021.07.021

Experimental Investigations on Surface Roughness and 3D Morphology

 in Dry Hard Turning of Hardened Steel with Different Hardness

Ma Furong，Tang Linhu，Li Baodong，Sun Yongji，Shen Jiancheng，Hu Yanjun

Abstract:The influence of cutting speed，feed，depth of cut，and workpiece hardness on the surface roughness and 3D morphology，and their mechanisms in dry hard turning of hardened mould steel Cr12MoV with different hardness (40±1HRC，45±1HRC，50±1HRC，55±1HRC，60±1HRC) by utilizing the PCBN inserts are experimentally investigated.The results show that the influence of cutting speed on surface roughness is more significant in dry hard turning of the hardened steel of 40±1HRC，45±1HRC，and 60±1HRC，compared to those with 50±1HRC and 55±1HRC hardness at the cutting speeds of 50m/min，250m/min，450m/min，650m/min，and 850m/min，and the roughness can reach 0.569μm.The surface roughness gradually decreases with the increase of cutting depth in turning workpieces of 60±1 HRC.The surface roughness is less than 1.00μm when the depth of cut reaches 0.15mm.However，the influence of feed is contrary to that of cutting depth.The surface roughness is less than 1.00μm when the feed is less than 0.15mm.The results also show that the ridges of the 3D morphology within the machined surface become blurred because they are subjected to the secondary damage resulting from high temperature in turning a softer workpiece.In turning of a harder workpiece，small grooves appears in the machined surfaces because of the ploughing effect resulting from the hard parcels between chiptoolworkpiece interfaces and the replication effect of the small groove in the tool flank face.

Keywords:dry hard turning；hardened steel；surface roughness；3D morphology