The production flowsheet of developed 0. 020% ~ 0. 060% S steel XGML40Cr (/% : 0. 38 ~ 0. 44C

0. 17 ~0. 30Si

0.60 ~0. 80Mn

≤0. 035P

0. 020 ~0. 060S

0. 90 〜1.1OCr

≤ 0. 01A1) for drill bit at Xingsteel is 50 t BOF-LF-285 mm x320 mm bloom casting-hot-rolling to Φ12 mm wire rod. The cutting test on 0. 027% S steel XGML40Cr and 0. 006% S steel ML40Cr with cutting feed rate 0. 015 mm/r

depth of cut 0. 1 mm and cutting speed 12 〜30 mm/min has been carried out. Test results show that the cutting performance of steel XGML40Cr is better than that of steel ML40Cr

i. e. its turning chip length is 1/5 ~ 3/5 that of steel ML40Cr； the heat productivity o

f steel XGML40Cr during cutting process is lower than that of steel ML40Cr

its blue turning chip ratio is 10% but that of steel ML40Cr is up to 70% ； and the cutting deformation coefficient of steel XGML40Cr is lower than that of steel ML40Cr and its surface roughness ( Ra 10. 2μm) is better than that of steel ML40Cr (Ra 22. 4μm). The mechanical properties of steel XGML40Cr is about equal to that of steel ML40Cr

its mechanical properties quenched at 870 °C and tempered at 500 ℃ are tensile strength 1 082 MPa

reduction of area 70%

HRC hardness value 40 and impact energy A

kv2

72 J.