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通过显微组织分析、拉伸试验、弯曲试验、冲击试验及旋转弯曲疲劳试验,对不同热调修温度下S355J2W+N低合金钢的显微组织、拉伸性能、冲击性能以及疲劳性能进行了研究。结果表明:700、800℃热调修后的S355J2W+N低合金钢显微组织为沿轧制方向呈带状分布的铁素体和珠光体,晶粒度约为8~9级;1000、1200℃热调修后的显微组织为粗大的多边形块状铁素体和珠光体,轧制带特征消失。采用800℃热调修时试件的抗拉强度最高;不同热调修温度下的试件均具有良好的弯曲性能;700、800℃热调修后试件具有良好的冲击性能,但1000、1200℃热调修后试件的冲击性能显著降低;调修温度对S355J2W+N低合金钢的疲劳性能影响不大。
The microstructure, tensile properties, impact properties and fatigue properties of S355J2W + N low-alloy steel under different thermal conditioning temperatures were studied by means of microstructure analysis, tensile test, bending test, impact test and rotating bending fatigue test the study. The results show that the microstructure of S355J2W + N low alloyed steel after hot tempering at 700 and 800 ℃ is a strip of ferrite and pearlite distributed along the rolling direction with a grain size of about 8-9. The microstructure after 1200 ℃ thermal conditioning is coarse polygonal massive ferrite and pearlite, and the characteristics of the rolled strip disappear. The tensile strength of the test piece is the highest when it is heated by 800 ℃; the test piece has good bending performance under the different thermal repair temperature; the test piece with 700,800 ℃ heat repair has good impact performance, The impact performance of the specimen after 1200 ℃ thermal conditioning was significantly reduced; the temperature of the repair had little effect on the fatigue properties of the S355J2W + N low alloy steel.