| Wear and tear will not only cause energy consumption,material waste,but also directly cause huge economic losses and social resources waste.As a result of wear and tear injury,the human and material resources needed to repair and stop work when replacing parts of machinery and equipment,as well as the economic losses caused by the decrease of labor productivity,are more serious.It is very important to study the wear performance of 45 steel and improve the wear resistance of materials for the construction of national economy and the long-term development,which will have a profound impact on the development of industry and economic construction in the future.Based on the existing ultrasonic generator and ultrasonic vibration system in the laboratory,the experimental platform of ultrasonic vibration surface deformation treatment device is designed and built independently.The ultrasonic vibration device was used to treat the surface specimen of 45 steel.Combined with different heat treatment processes,orthogonal experiments were used to explore the influence of ultrasonic vibration process parameters on the microstructure,hardness and wear resistance of the surface layer.Using metallographic microscope,scanning electron microscope,microhardness meter.The surface microstructure,hardness and wear resistance of the specimens were observed or measured by the friction and wear tester.The surface microstructure,hardness and wear resistance of the specimens were observed or measured by the friction and wear tester.Different heat treatments such as quenching,normalizing and sub-temperature quenching were studied before ultrasonic vibration deformation treatment.The samples after ultrasonic vibration treatment were tempered at different temperatures.The experimental results were observed and analyzed.The results show that the surface hardness of the raw sample is obviously improved.And under the condition of 45 N,20s vibration condition,the hardness value is the highest.Under the heat treatment condition of sub-temperature quenching,the surface hardness of the sample is not high,but its toughness is improved.The results show that the wear resistance of the original 45 steel samples without any treatment,the samples treated with ultrasonic vibration after quenching and the samples after 450℃ tempering will be improved,and the wear resistance of the samples after quenching heat treatment will be further improved after medium temperature tempering.The hardness of the test steel after tempering heat treatment changed to varying degrees with the change of tempering temperature,and there was a downward trend,in which the hardness of the sample after medium temperature tempering decreased the least,and the hardness of the sample after high temperature tempering decreased the most.But the effect is not very big.To sum up,the experimental results show that the best technological parameters of ultrasonic vibration surface deformation treatment samples are contact pressure of 45 N,vibration time of 20 s,Under this vibration condition,the grain size is the most meticulous and tight,the hardness value is the highest,and the wear resistance is the best.The surface layer of 45 steel can achieve the best performance by quenching heat treatment before ultrasonic vibration treatment and medium temperature tempering heat treatment after ultrasonic vibration treatment. |
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