论文部分内容阅读
本文研究了经不同工艺临界区热处理所获得的铁素体-马氏体双相低碳锰铌钢中组成相的形貌、马氏体体积率对二相亚结构和力学性能的影响以及冷形变时的成型性能。试验结果表明:随着热处理工艺的不同,改变了加热奥氏体化时的形核与成长机制,使双相钢中组成相的形貌与性能出现明显差别。铁素体相的位错密度与强度随马氏体体积率的增大而提高、但马氏体相的含碳量与强度则随马氏体体积率的增大而降低。双相钢的力学性质主要取决于两相的相对含量和组织形态。双相钢中的铁素体与马氏体的组织与性能和其单独存在时有显著差异。通常用以估计纤维增强复合材料强度的混合定律不适用于双相钢的强度计算。分析了原因并提出一个既能较好符合试验数据又能表达双相钢强度与马氏体体积率关系的数学式。从杯突与回弹试验的数据得出:当马氏体相含量在15—20%时,双相钢的强度与延塑性均比热轧状态有较大提高,同时仍保持着良好的成型性。
In this paper, the morphology, martensite volume fraction on the two-phase substructure and mechanical properties of the ferritic-martensite dual-phase low carbon manganese-niobium steel obtained by the heat treatment of the critical region of the different processes and cold Forming properties during deformation. The experimental results show that with the different heat treatment process, the nucleation and growth mechanism during the heating austenitization are changed, and the morphology and properties of the phases in the dual phase steel are obviously different. The dislocation density and strength of the ferrite phase increase with increasing martensite volume fraction, but the carbon content and the strength of the martensite phase decrease with increasing martensite volume fraction. The mechanical properties of duplex steel mainly depend on the relative content and morphology of the two phases. There is a significant difference between the microstructure and properties of ferrite and martensite in dual phase steels and their separate presence. The mixing law commonly used to estimate the strength of fiber-reinforced composites is not applicable to the calculation of the strength of duplex steels. The reason is analyzed and a mathematical formula that can not only accord with the experimental data well but also express the relationship between the strength of dual phase steel and the volume fraction of martensite is proposed. From the data of cup projection and rebound test, it can be concluded that the strength and ductility of dual phase steel are higher than that of hot rolled when the content of martensite is 15-20%, while still maintaining a good shape Sex.