摘要
研究了GDL-1型钢加热空冷回火后的冲击和拉伸性能的变化及显微组织和断口形貌。结果表明，该钢经920℃加热空冷后获得条束状过渡形态的贝氏体加少量岛状贝氏体组织。在300-350℃回火强韧性达到峰值，σb=1249MPa、σ0.2=929MPa、AKv=130J，400℃回火后的屈强比达到峰值0．83。400—600℃回火后，分布于贝氏体铁素体（BF）条束问的亚稳态残留奥氏体开始大量分解形成沿条束界连续分布的碳化物，在BF条内的高密度位错区也诱导析出细小碳化物钉扎位错产生二次硬化，出现不可逆回火脆性，冲击功和断面收缩率降低。由于稀土（RE）原子在原奥氏体晶界偏聚与Si原子产生交互作用抑制沿原奥氏体晶界沉淀出连续分布的碳化物，因此未见沿晶断裂特征。
The microstructures, morphologies of fracture surface and mechanical properties of the tempered GDL-1 bainite steel were investigated. The results show that the microstructure of the steel is the mixture of lath bainite and few granular bainite austenized at 920% then air cooling. The optimum strength and toughness are obtained after tempered at 300 - 350 ℃ with Orb = 1249 MPa,σ0.2 =929 MPa and AKV = 130 J. The maximum of yield/tensile ratio is 0. 83 after tempered at 400%. The retained austenite between laths and packets of bainite ferrite （BF） begins to decompose massively and forms the carbides continuously distributed along the lath and packet boundary of bainite in the temperature rang of 400 - 600 ℃, the carbides are also precipitated in high density dislocation area of BF, resulting in secondary hardening and irreversible temper brittleness and the impact energy and contraction ratio of area also reduced remarkably. Because of rare earth （RE） and Si element in steel which segregate on the original austenite grain boundary can restrain the precipitation of carbides along the original austenite grain boundary, so the pattern of intergranular fracture is not found.
出处
《金属热处理》
EI
CAS
CSCD
北大核心
2007年第2期83-86,共4页
Heat Treatment of Metals
基金
科技部中小企业创新基金(04c26215200858)
贵州省创新基金项目(024015)
贵州省人才专项基金(200412)
关键词
贝氏体钢
回火脆性
力学性能
碳化物沉淀
bainite steel
temper brittleness
mechanical properties
carbide precipitation
作者简介
陈伦军（1951．05-），男，四川成都人，教授，主要从事机械制造、机械强度的研究与开发工作，已发表论文40余篇，专著一部。联系人：梁益龙联系电话：08513663960 E-mail：Liangyilong@126．com
