将X100管线钢在850, 950, 1 050, 1 150 ℃淬火后再分别在250, 350, 550 ℃下回火, 以及将X100管线钢直接在250, 350, 550 ℃下回火, 分别用以研究再加热工艺对X100管线钢弯管和直管组织与性能的影响; 然后在不同温度下进行冲击试验, 并对淬火和回火前后的冲击断口形貌进行了分析。结果表明: X100管线钢经950 ℃淬火和550 ℃回火后, 显微组织为贝氏体、多边形铁素体和珠光体, 且其硬度适中, 冲击断口的纤维区、放射区、剪切区均呈韧窝形貌, 可与母管实现良好的强韧性匹配; X100管线钢在550 ℃直接回火后, 组织为回火索氏体, 组织均匀, 硬度适中, 可与母管相匹配。

The effects of reheat treatment on microstructure and properties of the bend pipe and straight pipe of X100 pipeline steel were studied by quenching them at 850, 950, 1 050, 1 150 ℃ and then tempering at 250, 350, 450, 550 ℃, or only tempering at 250, 350, 450, 550 ℃, respectively to gain the optimized technological parameters. The impact toughness was measured at different temperatures and the fracture morphology of samples before and after reheating treatment was analyzed. The results show that, when the steel was quenched at 950 ℃ and then tempered at 550 ℃, its microstruecture was B+PF+P, the hardness was moderate, the impact fracture exhibited good dimples in the fibrous region, radial region and shear zone, indicating a good match with the main pipe. When the steel was directly tempered at 550 ℃, the microstructure was homogenous, the hardness was moderate, also matched with the main pipe