222-paper－成分及冷却工艺对汽车用先进高强度钢组织、性能的影响.docVIP

成分及冷却工艺对汽车用先进高强度钢组织、性能的影响 张爱文 郑磊 (宝山钢铁股份有限公司研究院，上海201900) 摘 要：在试验室用50kg真空感应炉冶炼汽车用先进高强度钢，锻30mm厚板坯，经控制轧制轧成3mm厚板材后采用不同冷却模式进行控制冷却。研究了成分、冷却工艺对组织与力学性能的影响。结果表明：卷取温度降低，强度上升，延伸率下降，组织由铁素体+珠光体向贝氏体、马氏体转变；高温卷取时铌、钒等微合金元素对强度的贡献较明显，低温卷取时碳的贡献较大；强度提高后，延伸率下降；分段冷却对组织与性能的影响较复杂。通过不同的控制冷却工艺实现了用相同的成分获得不同强度等级要求的目的。 关键词：先进高强度钢；低合金高强度钢；复相钢；马氏体钢, 控制轧制，控制冷却 Effect of Chemical Compositions and Cooling Process on Microstructure and Mechanical Properties of Advanced High Strength Steel ZHANG Ai-wen ZHENG Lei (Research institute, Baoshan Iron and Steel Co., Ltd., Shanghai 201900) ABSTRACT: The advanced high strength steel was designed and melted by a 50kg vacuum induction furnace in laboratory, the 3mm finished sheet was rolled from forged 30mm slab and followed by controlled cooling. The effect of chemical compositions and cooling process on microstructure and mechanical properties were researched. The results show that the microstructure changes from ferrite plus pearlite to bainite and martensite, and the strength increases while the elongation decreases as the decreasing of coiling temperature. The strength increment of the sheet coiled at high temperature contributed by niobium and vanadium is much higher than that coiled at lower temperature, while the function of carbon goes to the opposite. The elongation of the sheet decreases as the increasing of strength. The effect of two-steps cooling process on microstructure and mechanical properties is complex. The different strength class steel can be manufactured by different cooling process in the same chemical composition. KEY WORDS AHSS，HSLA，complex phase steel，martensite phase steel，controlled rolling，controlled cooling 汽车用钢有很多品种，如图1所示。传统的低强度钢(LSS)和高强度钢(HSS)主要有无间隙原子钢(IF)、高强度无间隙原子钢(IF-HS)、普碳软钢(MILD)、各向同性钢(IS)、烘烤硬化钢(BH)、碳锰钢(C-Mn)以及低合金高强度钢(HSLA)、双相钢(DP)、相变诱发塑性钢(TRIP)等三个种类的部分低强度级别品种。传统的高强钢大多通过固溶、析出和细化晶粒作为主要强化手段。随着汽车产业的发展以及能源危机和环境问题的日益加剧，对车辆节能与安全的要求越来越高，车辆自重要求越来越轻以提高燃油经济性，于是先进高强度钢(AHSS)或者超高强度钢(Ultra-HSS)应运而生[1，2]。通常抗拉强度大于700MPa的钢种定为先进高强度钢（AH