粉末冶金烧结钢的加工性

通过烧结和在铣床上切削加工的实验，研究了添加硫化锰和氟化钙的烧结钢的加工性。结果显示，添加不同的改善切削加工性的第二相颗粒后的粉末烧结制品，其切屑形态有很大差异。添加硫化锰或氟化钙，其切屑变小，利于从孔中排出。在雾化前加入硫化锰的烧结制品，其加工性最好，1个d9．5mm的高速钢钻头可在其中钻凿532个总深13．51m的孔而毋需更换。硫化锰和氟化钙在混料过程中会发生团聚现象，降低了切削加工性。改善硫化锰和氟化钙的分布，将会改善切削加工性。

Machinability of powder metallurgical sintered steels

Machinability of P/M sintered steels with manganese sulfide and calcium fluoride additives is investigated and analyzed by experiments of sintering and cutting on milling machine. The results show that, the secondphase additives in sintered steels do not affect the sintering hardness obviously; different second-phase additive particles for enhancing machinability in sintered steels result in different shapes of cutting chips, i.e. the chips will become smaller when the particles of manganses sulfide and calcium fluoride are added during admixing, and those chips are easy to discharge from the drilling holes. The machinability of parts with pre-alloyed manganese sulfide before atomizing is the best, the number of holes drilled with an high-speed steel drill 9.5 mm in diameter arrives at 532 of a total length of 13. 51 m because the depth of each hole is 25. 4 ram. The MnS and CaF2 powders aggregate during admixing which reduces the machinability of P/M steels. To improve the homogeneity of manganese sulfide and calcium fluoride, the machinability could be enhanced.