工程机械用Q1100钢的热处理工艺

以一种屈服强度为1100 MPa的高强度工程机械用钢为对象,研究了再加热淬火温度(880～980 ℃)和回火温度(200～650 ℃)对Q1100钢显微组织和力学性能的影响。结果表明,淬火温度从880 ℃升高至980 ℃,试验钢的平均奥氏体晶粒尺寸从8 μm增加到24 μm,试验钢的屈服强度和抗拉强度都呈先升高后降低的趋势,并在920 ℃时达到最大,而-40 ℃冲击性能则随之持续降低。试验钢经920 ℃淬火+200～650 ℃回火后,随着回火温度的提高,试验钢的马氏体板条合并,板条形貌逐渐模糊,碳化物数量和形貌也随之发生改变,强度大幅下降,塑性和韧性则先降低后升高。试验钢最佳的热处理工艺为920 ℃淬火+200～250 ℃回火。

Heat treatment process of Q1100 steel for construction machinery

Effects of reheating quenching temperature (880-980 ℃) and tempering temperature (200-650 ℃) on microstructure and mechanical properties of a high strength construction machinery steel with yield strength of 1100 MPa were studied. The results show that with the increase of reheating quenching temperature from 880 ℃ to 980 ℃, the average austenite grain size of the tested steel increases from 8 μm to 24 μm, the yield strength and tensile strength first increase then decrease and with that at 920 ℃ being the maximum, while the impact absorbed energy at -40 ℃ continues to decrease. When quenched at 920 ℃ and then tempered at 200-650 ℃, with the increase of tempering temperature, the martensite laths of the tested steel are merged, the lath morphology is gradually blurred, and the number and morphology of carbides also change accordingly; and the strengths of the tested steel decrease greatly, while the plasticity and toughness decrease first and then increase. The optimal heat treatment process of the tested steel is: quenching at 920 ℃ and tempering at 200-250 ℃.