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研究了X80管线钢板不同温度回火后的组织与性能。结果表明,随回火温度升高,X80钢板的强度先升高后降低,由于抗拉强度相对于屈服强度变化较小,导致屈强比呈升高趋势;400℃回火时,屈服强度和抗拉强度分别达到最大值662.5 MPa和740 MPa;650℃以上回火时,DWTT值及冲击性能变差。X80钢板回火后组织为粒状贝氏体、针状铁素体以及珠光体,随回火温度升高,M/A组元发生分解,750℃回火时,残留奥氏体基本分解完毕。300℃低温回火时,X80钢板具有最佳的综合力学性能。
The microstructure and properties of X80 pipeline steel after tempering at different temperatures were studied. The results show that with the increase of tempering temperature, the strength of X80 steel sheet increases first and then decreases, and the yield strength increases with the small change of tensile strength relative to yield strength. When the tempering temperature is 400 ℃, the yield strength and The tensile strength reached the maximum of 662.5 MPa and 740 MPa, respectively. When the temperature was above 650 ℃, the DWTT value and the impact performance deteriorated. After tempering, the microstructure of X80 steel was granular bainite, acicular ferrite and pearlite. With the increase of tempering temperature, the M / A component decomposed and the retained austenite was decomposed basically at 750 ℃. 300 ℃ low temperature tempering, X80 steel has the best overall mechanical properties.