深冷处理对H13钢组织及力学性能的影响

Effect of cryogenic treatment on microstructure and mechanical properties of H13 steel

对H13钢深冷处理不同时间(0~4h)的组织演变及力学性能进行研究,借助XRD、SEM分析了物相及显微组织,借助硬度、冲击性能和拉伸性能试验对力学性能进行表征。结果表明,深冷处理可细化马氏体板条,促进残留奥氏体向马氏体转变以及带状碳化物析出;马氏体中C含量升高导致晶格常数增大,晶格畸变效应增强,XRD衍射峰向左移动。随着深冷处理时间的延长,强度和硬度呈上升趋势,韧性和塑性则逐渐降低;在保持硬度相同的情况下,H13钢深冷处理后与普通热处理相比,塑性相当,但强度和韧性均得到提升。

Microstructure evolution and mechanical properties of the H13 steel during cryogenic treatment for different time(0-4 h)were studied.The phases and microstructure were analyzed by XRD and SEM,and the mechanical properties were characterized by hardness,impact and tensile tests.The experimental results show that the cryogenic treatment can refine martensite laths,promote the transformation of retained austenite to martensite and the precipitation of banded carbide.The increase of C content in martensite results in increasing in lattice constant and in lattice distortion effect,and a shift to the left in the XRD diffraction peak.With the prolongation of cryogenic treatment time,the strength and hardness of the steel show an upward trend,while the toughness and plasticity gradually decrease.Under the condition of maintaining the same hardness,the plasticity of the H13 steel after cryogenic treatment is comparable to that of the normal heat treatment,and its strength and toughness are improved.