无磁奥氏体不锈钢热处理工艺研究

发布时间：2018-06-03 14:34

  本文选题：奥氏体不锈钢 + 热处理　； 参考：《华中科技大学》2015年硕士论文

【摘要】：在当今钢铁冶炼生产中,连铸技术被广泛地应用并且在不断地发展,如何提高连铸坯的质量是人们越来越关注的问题。为了提高板坯连铸生产过程中连铸坯的质量,针对其工作性能的需求,已经研制出了电磁搅拌用的设备——电磁搅拌辊(后文简称“电搅辊”),内部未凝固的钢坯通过电搅辊时,内部的熔体被电磁搅拌力搅动产生对流,从而细化晶粒。但无磁不锈钢筒体这个电搅辊的关键核心部件的材料,依然依赖从国外进口,国内的材料基本无法实现其功能需求。因此,研制能够满足实际使用需求的高性能无磁不锈钢筒体所用材料——无磁奥氏体不锈钢,对于摆脱对进口材料的依赖、降低生产成本具有非常重要的意义。本文主要对0Cr15Ni25Ti2MoAl VB奥氏体不锈钢的热处理工艺进行研究。本文首先对奥氏体不锈钢的成分、结构进行了介绍,然后阐述了本研究的理论基础,即各种合金元素在奥氏体不锈钢组织中的作用机理,合金组织中常见的M23C6、MC等碳化物和金属间化合物σ相、γ′相的结构及其对材料性能的作用机理,以及相变强化、固溶强化、位错强化、沉淀强化、细晶强化等奥氏体不锈钢强化的机理。接着基于所述理论基础,对0Cr15Ni25Ti2Mo Al VB奥氏体不锈钢首先进行了退火软化处理,室温进炉,随炉升温至500℃后保温4小时,随后取出空冷,此处理是为了使该材料便于机械加工。然后针对热处理工艺——固溶时效,设计四因素三水平的正交实验方案,探究相对最合理的热处理工艺参数。对经过不同热处理工艺方案的试样,分别从硬度、屈服强度、抗拉强度、断后伸长率等力学性能数据进行分析,得出结果:在固溶处理温度950℃下保温5h后油冷,时效处理温度720℃下保温14h后空冷的热处理工艺参数方案为最佳,材料的硬度达到306HB,屈服强度σs达到839MPa,抗拉强度σb达到1086MPa,断后伸长率δ为28.1%,材料力学性能优异,能够满足实际使用的需求。除此之外,用光学、电子显微镜对金相组织进行观察,晶体内大量的析出γ′相[Ni3(Ti,Al)]及各种碳化物,对比各方案的微观组织结构的差异,并结合各方案的硬度和力学性能进行分析,奥氏体不锈钢组织中析出γ′相、碳化物等对材料性能的影响十分显著。
[Abstract]:Nowadays, continuous casting technology is widely used in the production of iron and steel. How to improve the quality of continuous casting billet is more and more concerned. In order to improve the quality of continuous casting billet in the process of slab continuous casting, aiming at the demand of its working performance, An equipment for electromagnetic stirring has been developed-electromagnetic stirring roll (hereinafter referred to as "electric stirring roll"). When the inner unsolidified billet passes through the electric stirring roll, the melt inside is agitated by electromagnetic stirring force to produce convection, thus refining the grain size. However, the non-magnetic stainless steel cylinder, the key core component of the electric stirring roller, still depends on imported materials from abroad, and the domestic materials can hardly meet its functional requirements. Therefore, it is of great significance to develop the non-magnetic austenitic stainless steel, which can meet the practical application requirements, in order to get rid of the dependence on imported materials and reduce the production cost. The heat treatment process of 0Cr15Ni25Ti2MoAl VB austenitic stainless steel was studied in this paper. In this paper, the composition and structure of austenitic stainless steel are introduced at first, and then the theoretical basis of this study, that is, the action mechanism of various alloying elements in the microstructure of austenitic stainless steel, is described. The structure of carbides and intermetallic compounds 蟽 phase, 纬 'phase and their mechanism of action on the properties of materials, as well as phase transformation strengthening, solid solution strengthening, dislocation strengthening, precipitation strengthening, and so on, are common in alloy microstructure. Strengthening mechanism of austenitic stainless steel such as fine grain strengthening. Then, based on the theoretical basis, the 0Cr15Ni25Ti2Mo Al VB austenitic stainless steel was first annealed and softened, entered into the furnace at room temperature, kept for 4 hours after heating up to 500 鈩，

本文编号：1973133