A quenched and tempered steel for a large bearing ring was investigated. The heat treatment experiments were designed by using the L₉ (3⁴) type orthogonal form. Based on these conditions, a better combination of mechanical properties was obtained. The results showed that the quenching and the tempering temperatures were the most influential factors on the strength and toughness. The dislocation strengthening and the solid solution strengthening of the dissolved alloying carbides are the main mechanisms of increasing the strength by decreasing the tempering temperature and increasing the quenching temperature, respectively. The stripped carbides and long chain carbides strongly influence the differences in the tensile strength of the steels under different processes. The toughness AKv at −20 °C was increased by 42.2 J when the quenching temperature increased from 800 to 900 °C. The stripped undissolved carbides at lower quenching temperature promoted crack propagation and cleavage fracture and thus decreased the toughness of the steel. The AKv was increased by 47.4 J when the tempering temperature increased from 550 to 650 °C. The long chain carbides distributed along the grain boundary and the martensitic laths with a high density of dislocations at the lower tempering temperature decreased the toughness. Oil quenching can improve both the strength and toughness by refining the martensitic microstructure.

研究了用于大型轴承套圈的调质钢。热处理实验是使用L ₉（3 ⁴）类型正交形式。基于这些条件，获得了更好的机械性能组合。结果表明，淬火和回火温度是影响强度和韧性的最主要因素。溶解的合金碳化物的位错强化和固溶强化分别是通过降低回火温度和提高淬火温度来提高强度的主要机理。剥离的碳化物和长链碳化物在不同工艺下强烈影响钢的拉伸强度差异。当淬火温度从800°C增加到900°C时，在-20°C时的韧性AKv增加了42.2J。在较低的淬火温度下剥离的未溶解碳化物会促进裂纹扩展和解理断裂，从而降低钢的韧性。当回火温度从550°C升高到650°C时，AKv增加了47.4J。沿晶界分布的长链碳化物和在较低回火温度下具有高位错密度的马氏体板条降低了韧性。油淬可以通过细化马氏体组织来提高强度和韧性。沿晶界分布的长链碳化物和在较低回火温度下具有高位错密度的马氏体板条降低了韧性。油淬可以通过细化马氏体组织来提高强度和韧性。沿晶界分布的长链碳化物和在较低回火温度下具有高位错密度的马氏体板条降低了韧性。油淬可以通过细化马氏体组织来提高强度和韧性。