ZG230-450钢魏氏组织的微观结构与力学性能

Microstructure and Mechanical Properties of Widmansttten Structure in ZG230-450 Steel

通过金相组织分析 ,结合力学性能测定 ,探讨了ZG2 30 4 5 0钢中魏氏组织的微观结构 ,以及魏氏组织对裂纹的萌生和扩展的影响。结果表明 ,魏氏组织针由多个块状的亚晶粒组成 ,亚晶粒边界由位错缠结而成 ,在亚晶粒内有较高的位错密度 ;裂纹首先在晶界的析出物和缺陷处萌生并扩展 ,而魏氏组织对裂纹的扩展有较大的阻碍作用 ;魏氏组织的存在能提高钢的力学性能 ,特别是钢的强韧性 ,并降低钢的韧脆转变温度。

Based on the results of related metallographic structure analysis and measured data of mechanical properties,microstructure of Widmansttten structure in ZG230 450 steel and its influence on the initiation and propagation of crackle are studied.The results show that Widmansttten structure needle consists of many blocky subgrains that have higher dislocation density and subgrain boundary is made up of dislocation tangle.Slight crackle appears in the defect and the precipitate of grain boundary and begins to propagate.Widmansttten structure can distinctly prevent the crackle propagation and also enhance the mechanical properties especially the strength and toughness of steel,and lower the brittle transition temperature of steel.