碲对易切削钢硫化物及切削性能的影响

Effect of tellurium on the sulfide and machinability of free cutting steel

为研究碲(Te)冶金在易切削钢中的工业化应用效果,开展了向1215易切削钢中添加Te的工业化生产试验,并对其产品变化规律进行了分析。借助蔡司金相显微镜、小样电解、扫描电镜、能谱仪、维氏显微硬度仪、表面粗糙度仪等方法对比分析了1215易切削钢及1215Te易切削钢方坯、轧材中夹杂物的赋存、成分及切削性差异。结果表明,Te系易切削钢方坯中硫化物尺寸大且更均匀,趋向于球状;含Te轧材中夹杂物变形程度较小,轧制后夹杂物长宽比小于3的纺锤状为60%;轧材在进给量0.10 mm/r下切削时,1215Te钢产生的短螺卷屑比例为66.0%,大于1215钢的58.1%。在相同切削条件下,切削后的1215Te钢工件表面粗糙度小于不含Te的1215钢,说明Te显著提升了1215易切削钢的切削性能。

To explore the application of tellurium(Te) in the manufacture of free cutting steel, industrial tests were conducted by adding Te to 1215 steel and the effect of Te on the products were analyzed. Both the slab and rolled steels of 1215 and 1215 Te free cutting steels were analyzed using Zeiss metallographic microscope, non-aqueous electrolysis, scanning electron microscope with energy disperse spectrum, Vickers hardness tester, and surface roughness instrument. The effect of Te on the morphology, distribution, and composition of inclusions as well as machinability of the steel was studied. The results showed that Te coarsened and globalized the inclusions in the slab. The inclusions in 1215 Te steel had less deformability after rolling. Approximately 60 % of inclusions kept an aspect ratio less than 3 after rolling. Under the feed speed of 0.1 mm/r, the rolled steel of 1215 Te created 66.0 % of short screw chips, higher than that of 1215 steel(58.1 %). Under the same cutting conditions, the surface roughness of 1215 Te steel was far smaller than that of 1215 steel after machining. The machinability of 1215 steel is significantly improved by Te.