摘要
60Si2Cr VAT弹簧钢分别采用不同浓度PAG淬火介质和淬火油进行淬火,并在440℃和480℃的温度下进行回火处理,利用透射电镜和拉伸试验机等方法研究了该弹簧钢在不同淬火介质中淬火回火后的微观结构和力学性能的变化。结果表明,PAG淬火介质对其强度和塑性的影响显著。随着PAG浓度的增加,冷却速度降低,马氏体板条数量减少,板条宽度变大,强度和塑性呈现先增后降的趋势;冷速最快的5%PAG淬火回火后,针状的ε-碳化物未完全分解,容易在其尖端引起应力集中,使得力学性能较低;冷速最慢的油淬回火后,由于碳化物沿原奥氏体晶界和马氏体板条界析出,固溶度的下降,马氏体板条宽度的变大及数量的减少,最终也使得其强度、塑性和冲击韧性降低;只有冷速适中的13%PAG淬火后得到的综合力学性能最佳。
60Si2Cr VAT spring steel was quenched by different content of PAG quenchant and oil,and then tempered at 440 ℃ and 480 ℃respectively. Changes of microstructure and mechanical properties of the spring steel after quenching and tempering in different quenching mediums were investigated by use of transmission electron microscopy and tensile testing. The results indicate that a remarkable influence on strength and plasticity is emerged by quenching of PAG quenchant. With increasing the content of PAG,cooling rate decreases,the number of martensite lath reduces,while its width increases,strength and plasticity increase at first and then cut down. The plate-like ε-carbide haven＇t decomposed completely after 5% PAG quenching and tempering,which can cause the stress concentration easily at the tip and lead to the decrease of mechanical properties. Carbides precipitate along the prior austenite grain and martensite lath boundaries after quenching in oil and tempering,the decrease of solubility,larger width of martensite lath and less martensite which also result in extremely low strength,plasticity and impact toughness eventually; the best mechanical properties are obtained when quenching in 13% PAG.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2015年第12期134-139,共6页
Transactions of Materials and Heat Treatment
基金
贵阳市科技计划项目(筑科合同[2013101]5-1)
