硬质合金螺旋孔棒材尺寸精度控制与标准探讨

Discussion on Dimension Standard and Control Precision of Cemented Carbide Rods with Helical Coolant Holes

硬质合金螺旋孔棒材是一类尺寸精度要求高、成型难度大而具有高附加值的产品,属于粉末冶金行业重点研究的对象。本文从螺旋孔棒的螺距、同心度、孔径、孔间距等关键指标出发,探讨了螺旋孔棒的尺寸及公差标准,分析了螺旋孔棒尺寸精度的影响因素,进行了提高螺旋孔棒尺寸精度的工艺研究。研究结果说明:模具固化工艺制备的螺旋孔棒比电动调节工艺的内外螺距一致性更好;挤压速度对螺距的影响比挤压压力更大;内孔位置度以同心度表征比孔偏离更科学;孔间距的稳定性与力学平衡相关;通过对芯杆座的改进,三螺旋孔棒的孔夹角精度达到120°±4°。

The cemented carbide rods with helical coolant holes were the important products researched by powder metallurgy industry for high added value due to its dimensional accuracy and molding difficulty. In this paper, based on the key indicators as pitch, concentricity, hole diameter and hole interval, the dimension and tolerance standard of rods was discussed. The influencing factors of the dimensional accuracy were analyzed. The processing technology of improving the dimensional accuracy of rods with helical coolant hole was studied. The results show that the pitch of internal and external consistency pruducing by die curing technology is better than by electrodynamatic regulation. The effect of extruding speed on pitch is stronger than pressure. The concentricity is more scientific than hole position deviation. The stability of hole interval is related to the mechanical equilibrium.The hole angle accuracy of rods with three helical coolant holes can reach 120°±4°through the improvement ofthe core rod seat.