【摘要】 针对Q500qE桥梁钢板强度不稳定、屈强比高和冲击韧性差的问题，对其采用低C,Nb、Ti微合金化并添加Ni、Cr、Mo元素的化学成分设计，并对未再结晶区累计压下率和终冷温度对Q500qE桥梁钢板组织性能的影响进行了研究。结果表明：随着未再结晶区累计压下率增大，钢板组织中准多边形铁素体、针状铁素体和板条贝氏体含量增加，组织明显细化，钢板强度、屈强比和冲击韧性升高、横纵向强度差变大，断后伸长率降低。随终冷温度升高，钢板组织中准多边形铁素体含量增加、尺寸增大，板条贝氏体含量减少、板条束尺寸增大，钢板强度和屈强比降低、冲击韧性变差。根据研究结果，采用未再结晶区累计压下率60%、终冷温度520℃的工艺，Q500qE桥梁钢板综合性能最佳，其强度高、韧性好、屈强比低，横纵向强度差较小。更多还原

【Abstract】 In view of unstable strength, high yield ratio and poor impact toughness of Q500qE bridge plate, the effects of different accumulated reduction rate in non-recrystallization zone and final cooling temperature on the mechanical properties and microstructure of Q500qE bridge plate were studied by adopting low C, Nb and Ti microalloying and adding Ni, Cr, Mo elements. The results show that with the increase of the accumulated reduction rate in the non-recrystallized zone, the contents of quasi-polygonal ferrite, acicular ferrite and lath bainite increased, the structure was obviously fine, thus the strength, yield ratio and impact toughness increased, the difference of transverse and longitudinal strength increased, and the elongation decreased. With the increase of final cooling temperature, the content and size of quasi-polygonal ferrite increased, the content of lath bainite decreased and the size of lath bainite increased, thus the strength and yield ratio decreased, and the impact toughness deteriorated. With accumulated reduction rate of 60% in non-recrystallization zone and final cooling temperature of 520 ℃,Q500qE bridge plate which can achieve the best comprehensive performance has high strength, fine toughness and low yield ratio, and little difference of transverse and longitudinal strength.更多还原