论文部分内容阅读
通过开展不同冷却速率的对比试验,研究了超快冷工艺对高强度含Nb低合金钢组织与性能的影响。结果表明:相比于常规层流冷却,采用超快冷工艺进行冷却,钢材的屈服强度和抗拉强度均得到提高,伸长率略有下降但幅度不大;随着超快冷冷速的提高,钢材的晶粒尺寸逐渐细化,铁素体、珠光体等高温相变组织比例逐渐减少,贝氏体等中温相变组织比例增加,通过细晶强化和相变强化使得钢材的强度得到增加;同时钢中Nb的析出物数量增多且尺寸逐渐细化,使得钢材的强度得到进一步提高。
By carrying out comparative experiments of different cooling rates, the effect of ultra-fast cooling on the microstructure and properties of high strength Nb-containing low-alloy steel was studied. The results show that compared with the conventional laminar flow cooling, the ultra-fast cooling process is used to cool the steel. The yield strength and tensile strength of the steel are both improved, while the elongation is slightly decreased but the range is not large. With the rapid cooling rate The grain size of the steel is gradually refined, the proportion of high-temperature phase transformation structures such as ferrite and pearlite is gradually reduced, the proportion of medium-temperature phase transformation structure such as bainite is increased, and the strength of the steel is obtained through the fine grain strengthening and the phase transformation strengthening Increase; the same time, the amount of Nb precipitates in the steel increased and the size of the gradual refinement, making the steel strength has been further improved.