Study On Microstructure And Properties Of 6Cr2SiMnNiMoV Medium Alloy Steel

In order to reduce the number of tool changes and improve the tunneling efficiency of TBM(Full face rock tunnel boring machine,short for TBM)in hard rock,the material and heat treatment of hob ring for TBM are studied in this paper.The main conclusions are as follows:(1)The hardness of 6Cr2SiMnNiMoV steel increases with the increase of quenching temperature from 1000 to 1050?,and the maximum hardness of6Cr2SiMnNiMoV steel(HRC59.03)is obtained under the condition of quenching at1050?and tempering at 550?.The maximum impact toughness(7.1J/cm2)of6Cr2SiMnNiMoV steel was obtained under the condition of 1000 quenching and400?tempering.(2)The hardness of 6Cr2SiMnNiMoV-Nb increases with the increase of quenching temperature from 1000?to 1050?,and the hardness of6Cr2SiMnNiMoV-Nb increases with the increase of quenching temperature from 1050C to 1050 C.The hardness of 6Cr2SiMnNiMoV-Nb increases with the increase of quenching temperature from 1050?to 500?.The maximum hardness value(HRC58.47)was obtained for steel.The maximum impact toughness(8.3J/cm~2)of 6Cr2SiMnNiMoV-Nb steel was obtained under quenching at 1050?and tempering at 550?.(3)The impact toughness of 6Cr2SiMnNiMoV-Nb is better than that of6Cr2SiMnNiMoV steel,but its hardness is lower than that of 6Cr2SiMnNiMoV steel.(4)EDS(Energy Dispersive X-Ray Spectroscopy)analysis shows that the strengthening phases of 6Cr2SiMnNiMoV steel are V and Mo carbides,while those of6Cr2SiMnNiMoV-Nb steel are mainly V,Mo and Nb carbides.(5)Compared with 6Cr2SiMnNiMoV,6Cr2SiMnNiMoV-Nb exhibits lower relative wear resistance under test wear conditions.