550L板坯升级轧制600L牌号带钢试验研究

针对高强汽车钢生产合同量小、规格繁多，混浇坯和合同余材多的问题，以550L带钢的生产为例，研究了终轧温度、冷却速率对550L带钢组织以及力学性能的影响。结果表明，粗轧在再结晶区利用大变形量获得细小均匀的奥氏体组织；精轧采用低温轧制，获得内部有大量变形带的扁平状奥氏体组织，可以提高晶界面积，增加相变形核核心和驱动力，在随后的超快密集冷却过程中形成晶粒细小的铁素体组织，充分发挥细晶强化、相变强化、析出强化、位错强化的作用，使其性能达到高级别600L牌号带钢性能，实现了升级轧制，解决了上述问题。

Study on upgrading rolling of using 550L slab to 600L strip

Aiming at the problems of small quantity of contract,various specifications,mixed casting slab and a large of surplus material based on contract for high strength automobile steel production,taking the production of 550L strip as an example,the effects of finishing rolling temperature and cooling rate on the microstructure and mechanical properties of 550L strip were studied.The results show that a fine and uniform austenite structure can be obtained by large deformation of roughing rolling in the recrystallization zone.A flat austenite structure with a large number of deformed bands can be obtained by low temperature fishing rolling,which can increase the grain boundary area and the phase-deformation nucleus and driving force,and in the subsequent ultra-fast intensive cooling process,the fine-grained ferrite structure can be obtained.Therefore,the effects of grain refinement strengthening,phase transformation strengthening,precipitation strengthening and dislocation strengthening can be fully used to achieve high performance of strip,which reached 600L grade strip performance level.The upgraded rolling was realized and the above problems were resolved.