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应用Fe-Cr-W-Mo-V-Si-Mn-Ni-C系相平衡热力学计算,根据Cr-W-Mo-V高碳合金钢中碳化物在不同退火温度下的变化规律,给出各温度下的钢中相结构和相成分;并根据不同奥氏体化温度下的基体成分,推导合适的热处理工艺,并预测淬火硬度和回火硬度,最终确定试验钢的最佳化学成分。结果表明,试验钢在830℃退火,析出碳化物由M23C6、M6C和MC三种类型组成,其尺寸为0.2~0.5μm;在880℃淬火,未溶碳化物平均尺寸0.33μm。该钢在890℃淬火硬度为65.8 HRC,240℃回火时硬度为62.4~63.8 HRC,具有较高的抗回火性。实践表明,高碳合金钢的合金设计计算与少量的试验结合可以达到预期的目的。
Based on the phase equilibrium thermodynamics calculation of Fe-Cr-W-Mo-V-Si-Mn-Ni-C system, according to the variation law of carbides in Cr-W-Mo-V high carbon alloy steel at different annealing temperatures, The phase structure and phase composition of the steel at various temperatures; and according to the different austenitizing temperature of the matrix composition, derive appropriate heat treatment process, and predict the quenching hardness and tempering hardness, and ultimately determine the best chemical composition of the test steel. The results show that the test steel is annealed at 830 ℃. The precipitated carbides consist of three types of M23C6, M6C and MC with size of 0.2-0.5 μm. The alloy is quenched at 880 ℃ and the average size of undissolved carbides is 0.33 μm. The quenching hardness of the steel at 890 ℃ is 65.8 HRC, and the hardness at tempering at 240 ℃ is 62.4 ~ 63.8 HRC with high tempering resistance. Practice shows that high-carbon alloy steel alloy design calculations combined with a small amount of tests can achieve the desired purpose.