轧后穿水对20CrMnTiH组织和硬度影响的热模拟试验

降低热轧棒材的硬度有利于下游用户的加工。试验利用热模拟试验机研究终轧温度、轧后穿水以及冷床冷速对小规格20CrMnTiH钢棒材的组织比例和硬度的影响。在轧后不穿水的情况下，终轧温度越低或者冷速越慢，轧材的铁素体体积分数越高，贝氏体体积分数越低，轧材的硬度也越低。轧后穿水能明显提高轧材的铁素体比例，降低贝氏体比例，从而大幅降低轧材的硬度。穿水轧材硬度小于217HBW，满足退火或高温回火材的硬度要求。

Thermal simulation on effect of water cooling process on microstructures and hardness of 20CrMnTiH steel

Reducing the hardness of Bars is conductive to further processing. Effects of finishing rolling temperature, water cooling and cooling rate at cooling bed on the microstructures and the hardness of 20CrMnTiH small bars were in-vestigated by using a thermal simulator. Without water cooling,the ferrite proportions increase with the decreasing of fin-ishing rolling temperature and cooling rate at the cooling bed,while it is exactly the opposite for the bainite proportions. Thus,the hardness of bars decreases with the decreasing of finishing rolling temperature and cooling rate at the cooling bed. The ferrite proportions are increased,and the bainite proportions are decreased by water cooling. Therefore the hard-ness of bars is decreased significantly. The hardness of water cooling bar is less than 217HBW,which satisfies the hard-ness requirement for the annealing or high temperature tempering materials.