Effect of tempering temperature on the microstructure and mechanical properties of AISI 6150 steel was investigated. All samples were austenitized at 870 ℃ for 45 min followed by oil quenching, and then tempered at t...Effect of tempering temperature on the microstructure and mechanical properties of AISI 6150 steel was investigated. All samples were austenitized at 870 ℃ for 45 min followed by oil quenching, and then tempered at temperatures between 200 and 600 ℃ for 60 min. The results show that the microstructure of tempered sample at 200 ℃ mainly consists of tempered martensite. With increasing the tempered temperature, the martensite transforms to the ferrite and carbides. The ultimate tensile strength, the hardness and the retained austenite decrease with increasing tempered temperature, and 0.2% yield strength increases when the temperature increases from 200 to 300 ℃ and then decreases with increasing the temperature, but the elongation and impact energy increase with increasing the tempering temperature.展开更多
The nitride-strengthened martensitic heat resistant steel is precipitation strengthened only by nitrides.In the present work,the effect of nitride precipitation behavior on the impact toughness of an experimental stee...The nitride-strengthened martensitic heat resistant steel is precipitation strengthened only by nitrides.In the present work,the effect of nitride precipitation behavior on the impact toughness of an experimental steel was investigated.Nitrides could hardly be observed when the steel was tempered at 650℃.When the tempering temperature was increased to 700℃ and 750℃,a large amount of nitrides were observed in the matrix.It was surprising to reveal that the impact energy of the half-size samples greatly increased from several Joules to nearly a hundred Joules.The ductile-brittle transition temperature(DBTT) was also discovered to decrease from room temperature to 50℃ when the tempering temperature was increased from 650℃ to 750℃.The nitride precipitation with increasing tempering temperature was revealed to be responsible for the improved impact toughness.展开更多
基金Project(2011BAE13B03) supported by the National Key Technology R&D Program of China
文摘Effect of tempering temperature on the microstructure and mechanical properties of AISI 6150 steel was investigated. All samples were austenitized at 870 ℃ for 45 min followed by oil quenching, and then tempered at temperatures between 200 and 600 ℃ for 60 min. The results show that the microstructure of tempered sample at 200 ℃ mainly consists of tempered martensite. With increasing the tempered temperature, the martensite transforms to the ferrite and carbides. The ultimate tensile strength, the hardness and the retained austenite decrease with increasing tempered temperature, and 0.2% yield strength increases when the temperature increases from 200 to 300 ℃ and then decreases with increasing the temperature, but the elongation and impact energy increase with increasing the tempering temperature.
基金supported by the National Basic Research Program of China (Grant No. 2010CB630800)the National Natural Science Foundation of China (Grant No. 51001102)
文摘The nitride-strengthened martensitic heat resistant steel is precipitation strengthened only by nitrides.In the present work,the effect of nitride precipitation behavior on the impact toughness of an experimental steel was investigated.Nitrides could hardly be observed when the steel was tempered at 650℃.When the tempering temperature was increased to 700℃ and 750℃,a large amount of nitrides were observed in the matrix.It was surprising to reveal that the impact energy of the half-size samples greatly increased from several Joules to nearly a hundred Joules.The ductile-brittle transition temperature(DBTT) was also discovered to decrease from room temperature to 50℃ when the tempering temperature was increased from 650℃ to 750℃.The nitride precipitation with increasing tempering temperature was revealed to be responsible for the improved impact toughness.
