The Research And Development Of Abrasion-Resistant Steel Used For Bimetal Pipe

At present the domestic researches of Abrasion-resistant steel are mostly focused on the ones used in ordinary environment.There were little researches accomplished on the abrasion-resistant steel used for Bimetal Pipe. Combining with "The Development of Abrasion-resistant steel Used for Bimetal Pipe", a proper composition for the abrasion resistant steel used for bimetal pipe was designed, the heat treatment parameters were controlled appropriately.Finally a new abrasion-resistant steel used for Bimetal Pipe was reached and developed. The main thesis is as follows:(1)Using thermal simulation experiment MMS-300to determine the critical temperatures of tested steel, static and dynamic CCT curves of test steel were drawn. The impact of the holding temperature and cooling rate and deformation on continuous cooling transformation were discussed. It is suggested that martensite was got when the cooling rate was between3℃/s and20℃/s.The transformation temperature is decreased as the holding temperature and cooling rate were increased. It is also found that the transformation temperature is increased as the deformation is carried out.(2) Thermal simulation experiment was used to study the high deformation at high temperature. The factors which influence the stress were analysed. The metal constants were got:a=0.0136Mpa-1、n=4.2645、A=2.4x1016, the hot deform activation energy was calculateed as372.8KJ/mol. The expression of Z and the peaking stress were obtained. The stress model of test steel was got by traditional mathematic model and ANN.(3) The recrystallization rolling and off-line heat treatment was adopted. By setting different heat treatment parameters, the influences of quenching and tempering parameter were studied. Though TEM it was founded that the martensite lath got after quenching at890℃were crossed with each other and the width of martensite lath was200nm. When tempering temperature was between200℃-300℃, the tempering martensite kept the morphology of quenched martensite, tiny ε-carbides were separated out in the martensite lath. When tempering temperature reached350℃, the lath morphology of tempering martensite was fuzzy, the χ-carbide and θ-carbide was separated out as the temperature increased. Conglomeration and growing of carbide were took place as the temperature increased.(4) We can drawn the conclusion form the research of quenching technology that quenching temperature and the holding time had distinct influence on the microstructure and mechanical property. The test steel has the best mechanical property when quenched after holding at890℃for42min. Form the research of tempering technology we found that the hardness dropped remarkably as the tempering temperature increased. When tempered at300℃-400℃, temper brittleness of test steel appeared. The influence of tempering time on the hardness was slight.(5) MLD-10Abrasion test machine was used to study the abrasion mechanism of test steel. It was found that test steel after tempered at200℃had the best abrasion resistance property. The composition of test steel was adjusted to improve the combination mechanical property. When the content of Mn was increased to1.2%, the hardness and impact toughness of test steel achieved725HV and17.5J under suitable heat treatment.The study mentioned above has been applied in the cooperative factory. At the same time, the study can be referential to the further research and development of the Abrasion-Resistant Steel used for Bimetal Pipe...