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通过Formaster-F热膨胀仪和Gleeble-1500热/力模拟试验机分别模拟了奥氏体化温度为910℃和960℃时不同直径的无碳化物贝氏体/马氏体(CFB/M)复相钢圆棒在空气中的冷却速率,采用光学显微镜和扫描电镜分析了奥氏体化温度和冷却速率对CFB/M复相钢显微组织的影响,测定了CFB/M复相钢的硬度和冲击韧度值。结果表明,在空冷条件下,随圆棒直径增大,CFB/M复相钢的组织由无碳化物贝氏体+马氏体转变成铁素体+无碳化物贝氏体,硬度随之降低,但冲击功却显著增加。提高奥氏体化温度,可抑制铁素体析出,使CFB/M复相钢在更大的冷速范围内获得强韧性好的CFB/M复相组织。
The carbide-free bainite / martensite (CFB / M) composites with different diameters at austenitizing temperature of 910 ℃ and 960 ℃ were simulated by Formaster-F thermal expansion instrument and Gleeble-1500 thermal / Phase steel bar in air cooling rate, the use of optical microscopy and scanning electron microscopy analysis of the austenitizing temperature and cooling rate on the microstructure of CFB / M multiphase steel microstructure, measured the hardness of CFB / M duplex steel And impact toughness values. The results show that the structure of CFB / M duplex steel changes from carbide-free bainite to martensite to ferrite + carbide-free bainite with the increase of rod diameter under air-cooled condition, Lower, but the impact energy has increased significantly. Increasing the austenitizing temperature can inhibit the precipitation of ferrite and make the CFB / M duplex steel obtain the strong and tough complex structure of CFB / M in a larger cooling speed range.