GCr15SiMo钢中贝氏体含量对力学性能及干摩擦磨损性能的影响OA北大核心CSTPCD

Bearing is a key and indispensable part in mechanical equipment,which ensures the normal operation of the equipment.Bearings are widely used in real life,such as aerospace,heavy machinery,automobiles and ships,wind power generation,mining and agriculture,etc.However,as the demand for bearings increases and the working conditions become increasingly harsh,there are higher requirements for the performance and lifespan of bearings.Bainite bearing steel has been widely concerned because of its high strength,high toughness and low hydrogen embrittlement sensitivity.Obtaining the bainite microstructure of bearing steel requires isothermal quenching heat treatment,in which isothermal quenching temperature and isothermal quenching time are important parameters affecting the bainite structure and properties of bearing steel.The bainite microstructure with different contents can be obtained by adjusting the isothermal quenching time,thus affecting the strength,toughness and wear resistance of the material.The bainite content,in which the strength and toughness of bearing steel have a good match and enhance wear resistance,and the wear mechanism in the wear process are worthy of further study. The GCr15SiMo bearing steel was chosen as the research object in this work.The GCr15SiMo bearing steel with different bainite content was prepared.The microstructure and phase composition of the materials were analyzed,and the effects of the bainite content on the mechanical and wear properties were investigated.The microstructure change,phase content composition and mechanical properties of GCr15SiMo bearing steel after different isothermal quenching time were observed by scanning electron microscopy,3D morphology,transmission electron microscopy,field emission scanning electron microscope,X-ray diffraction,Rockwell hardness tester and impact tester.The friction and wear properties of samples with different bainite content were tested by HL-R7000 heavy-duty reciprocating friction and wear tester.The results showed that the content of bainite was increased from 14.5％to 83.5％when the isothermal quenching time was extended from 2 h to 72 h.The increase of bainite content and the decrease of martensite content resulted in the hardness reduction of the GCr15SiMo bearing steel,and the increase of impact energy.The wear rate showed a trend of first reduced and then increased.The wear mechanism mainly was adhesive wear and abrasive wear.When the content of ductile bainite was increased,the abrasive wear was more serious and the adhesive wear was light.From the wear section,it could be observed that cracks appeared on the observed section after the holding time of 2 h and 4 h.Holding time of 8 h had the least wear.If the holding time continued to be prolonged,the bainite content would increase,and the deformation area of the cross section of the specimen would become larger and larger after friction. In a word,when the isothermal quenching temperature is 210 ℃ and the holding time is 8 h,the bainite content is about 55.6％and the martensite content is 33.2％.At this time,the martensite and bainite phase in the microstructure have good strength-toughness combinations,therefore they show the better wear properties.