The microstructure and mechanical properties of the test 82B steel (0. 82%C

0.20%Cr) with 0. 02% ~ 0. 11% Mo Φ 12.5 mm rolled bar (end rolling at 950 °C

water cooling to 650 °C

air cooling) are measured by means of metallographic microscope

hardness tester

universal tensile testing machine and scanning electron microscope. The CCT curves of the test steels are simulated by JMATPRO teclinology. The results show that as the Mo content increases from 0.02% to 0. 11% ； (1) the depth of decarburization layer of 82B steel is all ≤0. 12 mm

and the HV hardness number is slightly increased from 305 to 317

(2) the proportion of sorbitic decreases slightly from 94% to 89%

the fineness of sorbitic lamella increase significantly. The yield strength increases from 655 MPa to 771 MPa

the tensile strength increases from 1 054 MPa to 1 139 MPa

the reduction of area increases from 38% to 52%

and the elongation has no significant change are about 12%

(3) The liigh temperature strengthening effect of micro Mo is obvious. At 600 °C

the yield strength increases from 316 MPa to 369 MPa

and the tensile strength increases from 358 MPa to 399 MPa.