三种低合金超高强耐磨钢的成型工艺及组织性能研究

发布时间：2018-03-21 06:01

  本文选题：超高强钢　切入点：马氏体　出处：《沈阳工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：本文采用优化合金的方法,自主设计了三种低合金超高强钢的合金成分,分别称为1#钢、2#钢和3#钢。对三种低合金超高强钢设计相应的轧制成形以及合理的热处理工艺,探索材料的最优强韧性匹配。分别采用光镜、扫描电镜对试样的微观结构进行观察和表征,采用万能试样拉伸机、硬度测试仪等测试材料的力学性能,采用模拟软件模拟三种低合金超高强钢的特征参数。同时,试样的耐磨性由热处理后试样的硬度和塑性进行表征。主要成果如下所示:本文通过对三种低合金超高强钢特征参数的模拟,得出各个钢种的相变点温度分别为:1#钢Ac1≈770℃,Bs≈400℃,Ms≈110℃;2#钢Ac1≈810℃,Bs≈440℃,Ms≈87℃;3#钢Ac1≈750℃,Bs≈430℃,Ms≈141℃。通过探索1#钢的一次等温球化退火、二次等温球化退火及正火+等温球化退火三种热处理工艺对热轧过程中带状组织的影响,发现一次等温球化退火与二次等温球化退火不能完全消除带状组织,而经过正火+等温球化退火工艺能够消除带状组织,且获得了良好的淬火前组织。对比1#钢的淬火与等温淬火工艺发现,经820℃淬火后,试样的基体组织基本为马氏体,此时材料的屈服强度和抗拉强度分别为1200MPa和1780MPa。经300℃等温淬火,基体组织为下贝氏体与马氏体混合组织,此时屈服强度为1220MPa、抗拉强度为1710MPa。相较于1#钢淬火后的性能,等温淬火后试样的强度降低,但塑性有所提升。2#和3#钢经相应的等温淬火处理后,其抗拉强度分别为1280MPa和1530MPa,屈服强度分别为1052MPa和1227MPa,同时2#钢经相应的等温淬火处理后,试样中的组织为下贝氏体、马氏体、碳化物和残余奥氏体,而3#钢基体组织主要为下贝氏体和残余奥氏体。通过三种高强钢的组织和性能研究分析可知:1#钢和3#钢的综合力学性能达到了本实验的目的,抗拉强度大于1500MPa,屈服强度大于1200MPa。但是,1#钢的力学性能要更优于3#钢,更能满足矿山研磨机钢球、破碎机颚板的要求。
[Abstract]:In this paper, the alloy compositions of three kinds of low-alloy ultra-high strength steels are designed by the method of optimizing alloys. The corresponding rolling forming and reasonable heat treatment process are designed for the three kinds of low-alloy ultra-high strength steels. The microstructure of the material was observed and characterized by light microscope and scanning electron microscope, and the mechanical properties of the material were tested by universal tensile machine and hardness tester. The characteristic parameters of three kinds of low-alloy ultra-high strength steels were simulated by simulation software. The wear resistance of the specimens is characterized by the hardness and plasticity of the specimens after heat treatment. The main results are as follows: in this paper, the characteristic parameters of three kinds of low-alloy ultra-high strength steels are simulated. The temperature of phase transition point of each steel is: Ac1 = 770 鈩，

本文编号：1642566