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本文介绍了高强度合金渗碳纲18Cr2Ni4WA,900℃加热淬火经不同温度回火后的组织与性能。试验表明:18Cr2Ni4WA钢经900℃淬火及低温(≤250℃)回火后,马氏体的板条形态基本不变,具有较佳的强韧性配合(σ_(D·2))约为120kgf/mm~2,σ_b可达145kgf/mm~2,C_v约为37ft-1b);中温回火(300～400℃)时,板条马氏体内的碳化物类型发生转变,形成脆性的θ碳化物(Fe_3C),使钢的韧性明显降低(即回火脆性);高温回火时(500～650℃),α相发生再结晶,θ碳化物聚集长大,钢的强度、硬度下降.塑性、韧性提高,但无第二类回火脆性。本文最后指出:18Cr2Ni4WA钢淬火后经200～250℃回火具有良好的强韧性,所以该钢不仅适用于制造渗碳淬火件,而且也适于制造整体淬火的高强度零件。
This paper introduces the structure and properties of high-strength carbides 18Cr2Ni4WA carburized by 900 ℃ quenching after tempering at different temperatures. The results show that the martensite lath morphology of 18Cr2Ni4WA steel after quenching at 900 ℃ and tempering at low temperature (≤250 ℃) has the same toughness (σ_ (D · 2)) of about 120kgf / mm ~ 2, σ_b up to 145kgf / mm ~ 2 and C_v ~37ft-1b). When tempered at 300 ~ 400 ℃, the carbide types in lath martensite transform to form brittle θ carbides (Fe_3C), the toughness of the steel is significantly reduced (temper brittleness); α-phase recrystallization occurs at high temperature tempering (500 ~ 650 ℃) Toughness increased, but no second temper brittleness. At the end of this paper, it is pointed out that 18Cr2Ni4WA steel has good toughness after being tempered at 200 ~ 250 ℃, so the steel is not only suitable for carburizing and quenching, but also suitable for manufacturing high strength parts with overall quenching.