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固态再生H11钢退火后微观组织与力学性能

Microstructure and mechanical properties of solid-state recycled H11 steels after annealing

  • 摘要: 为解决不同粒度车削屑粉末经压坯和挤压锻工艺后制备的固态再生H11钢韧性较差问题,研究了等温球化退火热处理工艺对H11车削屑固态再生钢微观组织和力学性能的影响,并对热处理H11钢的显微形貌、物相组成和力学性能进行了表征。最优等温球化退火热处理工艺如下:以10 ℃/min的速度从室温升温至880 ℃,保温3 h,随炉冷却至750 ℃,保温4 h,随炉冷却至550 ℃,出炉空冷。研究表明,等温球化退火处理实验钢的组织为球状珠光体和弥散分布的颗粒状碳化物;材料塑性变好,延伸率从3.4%升高到12.8%,但抗拉强度和硬度下降。车削屑粉末粒度影响H11车削屑固态再生钢在高温挤压锻后的强韧性,粒度越小,高温挤压锻后氧化越严重,强韧性越差。

     

    Abstract: To solve the poor toughness problem of the solid-state recycled H11 steels prepared by pressing and extrusion forging using the turning chip powders in different particle size, the influence of the isothermal spherodizing annealing process on the microstructure and mechanical properties of the steels was studied, and the microstructure, phase composition, and mechanical properties of the steels were characterized. The optimum isothermal spheroidizing annealing process is as follows: the temperature is rised from room temperature to 880 ℃ at the rate of 10°/min, holding for 3 h, and furnace cooling to 750 ℃, holding for 4 h, and then furnace cooling to 550 ℃, air cooling. In the results, the microstructure of the experimental steels is composed of the spherical pearlite and the dispersed granular carbide. The plasticity is improved, the elongation increases from 3.4% to 12.8%, but the tensile strength and hardness decrease. The particle size of the turning chip powders affects the strength and toughness of the solid-state recycled H11 steels after the high temperature extrusion forging. The smaller the particle size is, the worse the strength and toughness are, because of the serious oxidation after the high temperature extrusion forging.

     

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