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研究了碳含量1.26wt%的超高碳钢在等温淬火后的组织及其对拉伸力学性能的影响。结果表明,超高碳钢的等温淬火组织为超级贝氏体(superbainite)+残留碳化物的复相组织。超级贝氏体的形成是因为超高碳钢中的高碳成分及铝元素的添加。由于原奥氏体晶粒细化,超级贝氏体的形核率增加,长大路径缩短,使转变速率加快。形貌观察表明,贝氏体铁素体片和残留奥氏体薄膜的厚度只随着等温温度的降低而减小;奥氏体化温度对贝氏体铁素体片厚度没有影响,但超级贝氏体组织的尺寸会随奥氏体化温度提高而增加。拉伸试验结果表明,随着等温时间的延长,抗拉强度逐渐升高,但断后伸长率却先增加后减小;等温温度或奥氏体化温度升高均会引起抗拉强度降低,但伸长率增加。
The microstructure and mechanical properties of ultra high carbon steel with carbon content of 1.26wt% after isothermal quenching were investigated. The results show that the isothermal quenching microstructure of ultra-high carbon steel is the complex phase of superbainite + residual carbides. The formation of super bainite is due to the addition of high-carbon components and aluminum in ultrahigh-carbon steels. As the original austenite grain refinement, super bainite nucleation rate increases, growth path shortened, so that the transformation speed. Morphology observation shows that the thickness of bainitic ferrite and retained austenite films only decreases with the decrease of isothermal temperature; austenitizing temperature has no effect on the thickness of bainitic ferrite, but super The size of bainitic tissue increases with increasing austenitization temperature. Tensile test results show that with the extension of isothermal time, the tensile strength increases gradually, but the elongation at break increases first and then decreases; the isothermal temperature or the austenitizing temperature will cause the tensile strength to decrease, However, the elongation increased.