降低武钢CSP低碳酸洗钢SAPH370屈强比的实践

Practice for reduced yield ratio of SAPH370 steel made by CSP of WISCO

屈强比偏高是CSP低碳产品的共性问题。为降低CSP低碳酸洗钢SAPH370的屈强比,采取了不同轧制工艺(终轧温度FT7、卷取温度CT和冷却方式)进行试验,对不同工艺下的低碳酸洗钢的力学性能、晶粒尺寸和相组成进行了对比分析。结果表明:SAPH370钢采用终轧温度(FT7)为860℃、卷取温度(CT)600℃、后段快速冷却的工艺,在满足强度要求的前提下,屈强比可降低到0.8以下。观察到铁素体晶粒粗化、珠光体弥散分布。分析表明:CSP采用后段快冷工艺与传统热连轧的两段冷却工艺相当,有利于获得合适的铁素体晶粒度和弥散分布的珠光体。

High yield ratio was a common problem for low-carbon products made by CSP process. Different rolling processes （for finishing rolling temperature FT7, coiling temperature CT and cooling processes） were tested to reduce the yield ratio of SAPH370 steel. The mechanical properties of steel, grain size and phase composition with different processes were analyzed. The results indicated that： when finish rolling temperature （FT7） was 860 ℃, coiling temperature （CT） was 600 ℃ and the aft-stage rapid cooling process was adopted, the strength of the steel could meet requirements, and the yield ratio reduced to below 0. 8, coarse ferrite grain size and dispersed distribution pearlite were observed. The analysis showed that： aft-stage rapid cooling process by CSP was similar to the traditional two-stage cooling process, it was helped to get the appropriate ferrite grain size and dispersed distribution pearlite.