摘要
本文研究了30CrMnSiA 钢未溶铁素体+回火索氏体双相组织中铁索体形态、数量和尺寸对其强韧性的影响。结果表明:未溶铁素体呈针状双相组织的强韧性最佳;呈小颗粒状的次之;大颗粒状的最差。随铁索体数量的增加,未溶铁素体呈针状的屈服强度和硬度降低,而冲击韧性增加,强韧性基本不变;而呈颗粒状的在屈服强度和硬度降低的同时,由于铁素体颗粒尺寸增大,冲击韧性降低,强韧性下降。本文还探讨了铁素体形态、数量和尺寸对双相组织强韧性变化规律影响的原因。
This paper deals with the study of the effect of the morphology,amount and size of the dual phase of undissolved ferrite+tempered sorbite in30CrMnSiA steel on its strength and toughness.The results showed that theduplex structures with the acicular undissolved F have the highest strengthand toughness,those with the coarse granular F have the poorest strengthand toughess and those with the fine granular F have the medium strengthand toughness.With the amount of the acicular F increasing,the yieldstrength and the hardness of the duplex structure decrease,while the im-pact toughness increases,and the strength and toughness gets little changed.But with the amount of granular F increasing,the yield strength and thehardness of the duplex structures decrease,while,due to the enlargement insize ef the F,the impact toughness decreaes,and the strength and toughness:become poor.Crack formation and development in all the duplex structures were observedby section-metallographic-specimen of fracture.Cracks always start on theinterfaces between the undissolved F and tempered sorbite in all the duplexstructures.Crack developes along the interface and cutting the F alterna-tively in the acicular duplex structure or only along the interface in the finegranular duplex structure.In the coarse granular structure,cleavage fractureoccurs through the F.The machanism of the effect of the morphology of the F on the strengthand toughness was discussed.
关键词
亚温淬火
强韧性
30CRMNSIA钢
intercritical heat treatment(IHT)
duplex structure
strength and toughness
crack
