固溶时效处理对铬钼钒合金化球墨铸铁碳化物形态及高温压缩强度的影响

    Effects of Solution Aging on Carbide Morphology and High Temperature Compressive Strength of Cr-Mo-V Alloyed Ductile Iron

    • 摘要: 基于热作模具钢与高温合金的成分设计和热处理原理,采用水平连铸技术制备了含Mo、Cr、V等元素的合金化球墨铸铁,并对其进行了固溶-时效热处理。通过光学显微镜(OM)和X射线衍射(XRD)等方法对样品的微观结构进行分析,并通过洛氏硬度测试和500℃高温压缩实验评估其力学性能,探索合金元素和碳原子对铬钼钒合金化球墨铸铁强度与硬度的影响机制。结果表明,部分一次碳化物即使在升高固溶温度和延长固溶时间后仍未能完全分解;在固溶温度为1050℃、固溶时间为1 h下,获得的微观组织最有利于后续的时效处理;在固溶温度1050℃、固溶时间1 h、时效温度500℃时,铬钼钒合金化球墨铸铁表现出最佳的力学性能,洛氏硬度达55.9 HRC,高温压缩强度为2144.6MPa;随着摩擦载荷的增加,该合金的摩擦系数逐渐减小。

       

      Abstract: Based on the composition design and heat treatment principles of hot work die steel and high-temperature alloys, the horizontal continuous casting technology was employed to prepare Mo, Cr, and V-alloyed ductile iron. The alloy was then subjected to solution-aging heat treatment. The microstructure of the samples was analyzed using optical microscopy(OM) and X-ray diffraction(XRD), while the mechanical properties were tested using Rockwell hardness and hightemperature compression tests at 500 ℃. The mechanisms by which alloy elements and carbon atoms influenced the strength and hardness of the Mo-Cr-V alloyed ductile iron were explored. The results show that, some primary carbides do not decompose, even with elevated solution temperatures and prolonged solution time. The microstructure obtained under a solution temperature of 1050 ℃ and a solution time of 1 h is most favorable for subsequent aging treatment. At a solution temperature of 1050 ℃, a solution time of 1 h, and an aging temperature of 500 ℃, the Mo-Cr-V alloyed ductile iron achieves the best mechanical properties, with a Rockwell hardness of 55.9 HRC and a high-temperature compressive strength of 2144.6 MPa. Additionally, the friction coefficient of the alloy decreases as the load in the friction and wear tests increases.

       

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