正交切削淬硬45钢绝热剪切临界条件实验研究

摘要

进行了3种硬度淬硬45钢的正交切削实验,通过金相观测研究了切削条件对第一变形区绝热剪切的影响,得到了淬硬45钢在正交切削过程中的绝热剪切临界切削条件,并分析了平均切削力和切屑变形.结果表明：淬硬45钢的绝热剪切临界切削速度随着切削厚度的减小或刀具前角的增大而增大.材料硬度越高,临界切削速度越小.在绝热剪切发生时,平均切削力不发生突变.在绝热剪切发生之前,带状切屑的变形系数随着切削速度的增大而减小,并逐渐趋近于1.%The orthogonal cutting experiments of three kinds of hardness hardened 45 steel are performed.The influences of cutting conditions on adiabatic shear in the first deformation zone are studied through metallurgical observation,and the adiabatic shear critical cutting conditions in orthogonal cutting process of hardened 45 steel are obtained.The change of average cutting force and the chip deformation are also analyzed.Results show that the adiabatic shear critical cutting speed increases with the decrease of the undeformed chip thickness and the increase of the rake angle.Furthermore,the critical cutting speed is smaller when the material hardness is higher.The average cutting force has not a sudden change when the adiabatic shear occurs.Before the occurrence of adiabatic shear,the deformation coefficient of flow chip decreases obviously with the increase of cutting speed and tends to unity.