易切削不锈钢中氧含量和锻造比对硫化物形态及切削性能的影响

摘要：易切削不锈钢中硫化物的类型和形貌对切削性能具有重要影响。运用扫面电镜分析、热力学计算、锻造实验、切削实验等方法研究了氧含量和锻造比对易切削不锈钢中硫化物的类型和形貌的影响，以及对切削性能的影响。实验结果表明：随着铸态钢中氧含量的增加，MnS包裹(Mn，Cr)O等氧化物的复合硫化物数量增多，第Ⅰ类硫化物的比例上升，硫化物数量减小，尺寸和面积比增加。在锻造过程中，高氧含量（TO质量分数0.021%）钢样中复合硫化物沿锻造方向变形较小，平均长宽比小于3，钢中硫化物呈纺锤形或球形均匀分布。切削实验发现，高氧含量钢样（TO质量分数0.021%）比低氧含量钢样（TO质量分数0.007%）具有更小的切削力和表面粗糙度，刀具使用寿命增加了44.1%，切削性能整体得到提高。

Influence of oxygen content and forging ratio on sulfide morphology in free-cutting stainless steel and their cutting performances

The type and morphology of sulfide in free-cutting stainless steel have important influence on the cutting performance. The effects of oxygen content and forging ratio on the type and morphology of sulfide in free-cutting stainless steel, as well as the influence on the cutting performance were studied using scanning electron microscopy(SEM), thermodynamic calculation, forging experiment and cutting experiment. The results show that with the increase of oxygen content in cast steel, the compound sulfide containing oxides such as (Mn, Cr)O increases, the proportion of type I sulfide increases, the amount of sulfide decreases, and the size and area ratio increases. In the forging process, the composite sulfide in high oxygen content sample (TO content of 0.021 mass%) has a small deformation along the forging direction, with an average aspect ratio less than 3, which promotes the spindle shaped or spherical uniform distribution of sulfide in the steel. By comparing the experimental results of cutting performance of each sample, it is found that the high oxygen content sample (TO content of 0.021 mass%) has less cutting force and surface roughness than the low oxygen content sample (TO content of 0.007 mass%), the tool service life is increased by 44.1%, and the overall cutting performance is improved.