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研究了N80级电阻焊石油套管钢经不同温度回火的组织和性能的关系。结果表明,在500～650℃范围,随回火温度上升,强度逐渐下降;塑性和韧性在500～560℃变化不大,560～650℃明显上升。回火温度的升高,显微组织由板条状铁素体向多边形铁素体转变,析出的碳化物长大,球化。500～560℃回火得到的组织和性能较佳,屈服强度达到590～705 MPa,抗拉强度达到710～770 MPa。
The relationship between the microstructure and properties of N80 grade oil resistant casing steel tempered at different temperatures was studied. The results show that the strength decreases gradually with the increase of tempering temperature in the temperature range of 500-650 ℃. The plasticity and toughness change little at 500-560 ℃ and increase obviously at 560-650 ℃. Tempering temperature increases, the microstructure changes from lath ferrite to polygonal ferrite, precipitation of carbide growth, spheroidization. The microstructure and properties obtained by tempering from 500 ℃ to 560 ℃ are good, the yield strength reaches 590 ~ 705 MPa and the tensile strength reaches 710 ~ 770 MPa.