309L奥氏体不锈钢板热轧边裂缺陷成因分析和工艺改进

Process Improvement and Edge Crack Analysis of 309L Austenitic Stainless Steel Plate in the Hot Rolling

通过金相组织观察和热力学计算相结合的方式对309L奥氏体不锈钢板热轧边裂缺陷进行了分析。试验结果表明,309L钢(0.012%C,0.034%N)板坯热轧加热温度1260℃边部三角区存在大量网状铁素体,在后续加热过程中高温铁素体含量进一步升高,达到24%左右,导致塑性降低,轧制过程中产生边裂缺陷。通过控制钢中C含量0.015%~0.025%,N含量0.04%~0.05%,热轧板加热温度1150℃,使钢中铁素体含量降至10.7%,有效避免309L钢板边裂,板卷合格率达100%。

The edge crack cause of 309 L austenitic stainless steel plate in the hot rolling is analyzed by means of metallographic structure observation and thermodynamic calculation.Results test show that the hot rolling temperature of steel plate 309 L(0.012% C,0.034% N) is at 1 260℃and large area of continuous reticular δ ferrite exists in the triangle area of slab edge.In the subsequent heating process,the ferrite content increased continuously to up 24%,which lead to the decrease of plasticity and formation of edge crack in rolling process.By controlling 0.015%~0.025% C,and 0.04% ~0.05% N in steel,and slab heating at 1 150℃,the ferrite content in steel decreases to 10.7% to be available to avoid the edge crack of 309 L steel plate and coil qualified rate up to 100%.