CAJ | 학술논문

为改善高强度钢的塑性和韧性，对中碳低合金马氏体高强度钢分别采用常化后空冷+回火和常化后控冷+回火工艺，研究常化后冷却工艺对钢中残余奥氏体及力学性能的影响.采用扫描电镜获得钢的组织形态，利用X射线衍射和电子背散射衍射技术分析钢中残余奥氏体的体积分数、形貌和分布.发现两种工艺下均得到板条马氏体+残余奥氏体组织，残余奥氏体均匀分布在板条之间，随工艺参数不同，其体积分数在3%~10%变化.常化后加速冷却能显著细化马氏体板条，提高钢的屈服强度和抗拉强度100 MPa以上，冲击功下降4 J.残余奥氏体的体积分数随常化控冷终冷温度的升高呈现先升高后降低的变化，常化后的控制冷却也可以作为进一步改善马氏体类型钢组织和性能的方法.
위개선고강도강적소성화인성，대중탄저합금마씨체고강도강분별채용상화후공랭+회화화상화후공랭+회화공예，연구상화후냉각공예대강중잔여오씨체급역학성능적영향.채용소묘전경획득강적조직형태，이용X사선연사화전자배산사연사기술분석강중잔여오씨체적체적분수、형모화분포.발현량충공예하균득도판조마씨체+잔여오씨체조직，잔여오씨체균균분포재판조지간，수공예삼수불동，기체적분수재3%~10%변화.상화후가속냉각능현저세화마씨체판조，제고강적굴복강도화항랍강도100 MPa이상，충격공하강4 J.잔여오씨체적체적분수수상화공랭종랭온도적승고정현선승고후강저적변화，상화후적공제냉각야가이작위진일보개선마씨체류형강조직화성능적방법.
The effects of two different processes, normalizing with air cooling + tempering and normalizing with controlled cooling+ tempering, on the retained austenite and mechanical properties of medium-carbon low-alloy martensitic ultra-high strength steel were investigated to improve its plasticity and toughness. The microstructure of the steel was observed by scanning electron microscopy ( SEM) . The volume fraction, shape and distribution of retained austenite in the steel were measured by X-ray diffraction ( XRD) and electron back-scattering diffraction (EBSD). The results show that lath martensite and retained austenite (M+RA) are obtained by the two processes and a uniform distribution of retained austenite is located between lath martensites. The volume fraction of retained austenite varies from 3% to 10% with treatment parameters. Normalizing with controlled cooling can significantly refine lath martensite while the yield strength and tensile strength increase more than 100 MPa and the impact energy decreases by 4 J. When the quenching temperature rises, the volume fraction of retained martensite increases firstly and then decreases. Normalizing with controlled cooling can also act as a method for improving the microstructure and properties of martensitic steel.