不同塑性变形工艺对铁基合金组织和性能的影响

发布时间：2018-05-22 14:24

  本文选题：中碳钢 + 晶粒细化　； 参考：《华北理工大学》2017年硕士论文

【摘要】：通过对不同初始组织中碳钢和工业纯铁进行不同轧制道次的温轧及退火试验,研究了不同塑性变形工艺对铁基合金组织和性能的影响规律。温轧过程中,铁素体发生动态回复与再结晶,晶粒尺寸随轧制道次增加而减小。8道次温轧,工业纯铁的平均晶粒尺寸为5.11μm,马氏体钢和伪共析钢的晶粒尺寸分别减小至0.77μm和0.52μm。由拉伸试验可得,8道次温轧后,工业纯铁的强度和塑性均较低,马氏体钢的屈服强度虽较高,但延伸率较低,且无均匀变形阶段;只有伪共析钢的综合性能得到明显改善,8道次温轧的屈服强度和均匀延伸率分别为1167.0MPa和6.2%,表现出相当的均匀变形能力。8道次温轧后,对马氏体钢和伪共析钢进行后续600℃退火处理。马氏体钢组织具有较强的热稳定性,晶粒尺寸随退火时间延长增大幅度较小。伪共析钢退火时,铁素体晶粒尺寸呈双峰分布。对轧后退火试样进行拉伸试验,试验材料的强度随退火时间的延长而逐渐降低。相同保温时间内,伪共析钢的屈服强度和马氏体钢接近,但均匀延伸率明显高于马氏体钢,因而显示出更好的强韧性,均匀变形能力更强。实验结果表明,与相同工艺下其他试验材料相比,伪共析钢温轧及退火后的强韧性显著提升,这主要是由于伪共析钢在温轧和退火处理后,显微组织呈多尺度晶粒带状分布或晶粒尺寸双峰分布,因而能够在变形过程中引起应变梯度效应,诱发几何必须位错的产生,使加工硬化能力增强,综合性能提升。
[Abstract]:The effects of different plastic deformation processes on the microstructure and properties of Fe-base alloys were studied by warm rolling and annealing tests of carbon steel and industrial pure iron with different initial microstructure. Dynamic recovery and recrystallization of ferrite occurred during warm rolling. The grain size decreased with the increase of rolling pass. The average grain size of industrial pure iron was 5.11 渭 m, and the grain size of martensite steel and pseudoeutectoid steel decreased to 0.77 渭 m and 0.52 渭 m, respectively. The tensile test shows that the strength and plasticity of industrial pure iron are lower after 8 passes of warm rolling. The yield strength of martensitic steel is higher, but the elongation is lower, and there is no uniform deformation stage. Only the comprehensive properties of pseudoeutectoid steel were improved obviously, the yield strength and uniform elongation of 8 pass warm rolling were 1167.0MPa and 6.2, respectively, showing a considerable uniform deformation ability after 8 pass warm rolling. Martensitic steel and pseudoeutectoid steel were annealed at 600 鈩，

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