水温对冷轧马氏体钢板淬火冷却速度和性能的影响

Effect of water temperature on the cooling rate and mechanical properties of a cold rolled martensitic steel sheet

冷轧马氏体钢板以其高强度特点,在汽车零部件制造中具有较大的减重潜力,逐步获得越来越多的应用。冷轧马氏体钢板一般采用具有水淬冷却功能的连续退火机组生产,水淬过程工艺参数对马氏体钢板的组织和性能影响很大。以C-Mn系冷轧马氏体钢板为研究对象,研究水温对淬火冷却速度、钢板的力学性能和组织的影响。结果表明,在室温较低的情况下,马氏体薄钢板的冷速可达近1 000 K/s。随着水温的变化,不仅平均冷却速度发生改变,而且瞬时冷却速度曲线的形状也发生较大的变化。水温提高导致冷却速度下降,从而导致马氏体钢板强度和组织的较大变化。这种变化规律,对于马氏体钢板性能稳定控制有一定的参考意义。

Cold rolled martensitic steel sheet is becoming more and more widely applied in carmaking industry because of its unique attribute of ultra high strength,which enables high potential for light weighting. Martensitic steel sheet is typically produced with continuous annealing lines equipped with water quenching section,and the parameters for water quenching is crucial for the microstructure and mechanical properties. A cold rolled martensitic steel sheet with C-Mn is chosen to study the effect of water temperature on the cooling rate,microstructure and mechanical properties. The results show that the water cooling rate can be as high as 1 000 K / s for thin gauge martensitic steel sheet at low water temperatures. And,further more,not only the average cooling rate changes with the water temperature,but also the shape of the simultaneous cooling curve changes significantly. The increase of water temperature leads to the significant decrease of cooling rate and results in remarkable change in the microstructure and mechanical properties of the experimental steel sheet. These experimental results can be beneficial reference for the stability control of the mechanical properties of martensitic steel sheets.