Analysis of phase composition

particle size and hardness of metallographic structure and sulfide inclusions in 1215MS free cutting steel Φ12 mm coil are carried out by means of optical microscope

scanning electron microscope with energy dispersive spectrometer

microhardness tester and thermdynamic software Thermo-Calc. The results show that

the proportion of ferrite in 1215MS steel is 93% -96%

and the proportion of pearlite is 4% ~5% ; the average equivalent diameter of ferrite is 22.30 μm

the average diameter of pearlite is 16. 83 p.m

sulfide is evenly distributed in the edge of grain boundary and the ferrite

the equivalent diameter of sulfide is 5.077μm

the average Vickers hardness of MnS

ferrite

and pearlite is 80 HV10

100 HV10

175 HV10

respectively.