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利用水和空气作为淬火介质,对直径为80 mm的Fe-2.4C-12Cr高铬铸球进行多循环淬火-分配-回火(MQ-P-T)处理,并与常规正火和油淬处理后的同尺寸试样的力学性能和微观组织进行对比分析。通过微观表征技术,对MQ-P-T处理后高铬铸铁的强韧化机制进行了探讨。结果表明,经MQ-P-T处理后的高铬铸球径向硬度平均值约为60 HRC,比空冷铸球径向平均硬度约高出17 HRC,比油淬处理试样约提高5 HRC。经MQ-P-T处理后铸球冲击韧度平均值达到12.6 J/cm2,约为空冷冲击韧度的4倍,约为油淬冲击韧度的2倍。经MQ-P-T处理后铸球具有高的硬度和硬度均匀性,其冲击性能亦大大提高。经MQ-P-T处理后铸铁优异的力学性能主要归因于马氏体基体、相当数量的二次碳化物和稳定的残留奥氏体组织。
The quenching-distribution-tempering (MQ-PT) treatment of Fe-2.4C-12Cr high chromium cast balls with a diameter of 80 mm was carried out using water and air as the quenching medium. After normalizing and oil quenching The same size of the mechanical properties of the sample and microstructure comparative analysis. The mechanism of strengthening and toughening of high chromium cast iron after MQ-P-T treatment was discussed by means of microscopic characterization. The results show that the average hardness of the high chromium cast balls treated by MQ-P-T is about 60 HRC, which is about 17 HRC higher than the average radial hardness of the cast balls and about 5 HRC higher than that of the oil quenched samples. After MQ-P-T treatment, the average impact toughness of cast ball reached 12.6 J / cm2, which is about 4 times of air-cooled impact toughness, which is about 2 times of oil-quenched impact toughness. After MQ-P-T treatment cast ball with high hardness and hardness uniformity, the impact performance is also greatly enhanced. The excellent mechanical properties of cast iron after MQ-P-T treatment are mainly due to the martensite matrix, a considerable amount of secondary carbides and stable residual austenite.