高耐磨圆钢硬度控制生产实践

Production practice of hardness control for high wear resistant round steel

特钢新中型车间在生产ø110 mm高耐磨合金钢时发现硬度超标,通过热模拟试验测得该钢种CCT曲线,得到不同冷速对相变的影响规律及组织硬度。结果表明,当冷速不大于0.2℃/s时,主要发生铁素体和珠光体相变,硬度不大于20.5HRC;当冷速在0.5~2℃/s时,主要发生贝氏体和马氏体相变,硬度在40~51.7HRC之间;当冷速不小于4℃/s时,主要发生马氏体相变,硬度不大于54.4HRC。根据CCT曲线可知,车间轧制过程中必须控制冷速小于0.2℃/s时,才可获得硬度不大于21HRC的圆钢。

It was found that the hardness exceeded the standard when producingø110 mm high wear-resistant alloy steel in the new medium-sized workshop of Special Steel Group.The CCT curve of the steel was measured through the thermal simulation test.The influence law of different cooling rate on phase transformation and microstructure hardness was obtained.The results showed that when the cooling rate was not higher than 0.2℃/s,the ferrite and pearlite transformation mainly occurred,and the hardness was not higher than 20.5HRC.When the cooling rate was in range of 0.5-2℃/s,the bainite and martensite transformation mainly occurred,and the hardness was in range of 40-51.7HRC.When the cooling rate was not less than 4℃/s,the martensitic transformation mainly occurred,and the hardness was less than or equal to 54.4HRC.According to the CCT curve,the round steel with hardness less than or equal to 21HRC could be obtained only when the cooling rate was controlled below 0.2℃/s in the rolling process in the workshop.