控轧控冷工艺下Mn-Ti型高强钢组织与性能的研究

发布时间：2018-01-21 02:25

  本文关键词： 控轧控冷 Mn-Ti型高强钢 拉伸性能 冲击韧性 Gleeble-3800　出处：《中北大学》2017年硕士论文　论文类型：学位论文

【摘要】：钢铁产业是我国国民经济的支柱性产业,目前我国钢铁产业正处于化解产能过剩的关键时期,另外国内外众多领域用钢也提出了更高强度、更好塑性以及一定韧性和良好焊接性的要求。控轧控冷工艺作为21世纪一项新技术,控轧控冷技术下低碳微合金化高强度钢不仅在改善钢材的综合性能方面取得了明显的效果,在钢铁生产上得到广泛应用,而且控轧控冷技术在减少能源消耗发展制造绿色钢铁材料发挥了重要作用,是目前各国钢铁学者的研究热点。本文主要研究了控轧控冷工艺下低碳微合金Mn-Ti型钢在室温拉伸变形、低温冲击及热压缩状态下,得到实验钢在不同实验参数下的微观组织和力学性能,分析其微观组织的演变过程,及组织对实验钢力学性能的影响,结合实验钢具体的使用条件和要求,为钢铁实际生产过程控轧控冷工艺参数制定提供理论依据,具体研究内容如下:(1)研究Mn-Ti型实验钢分别在20℃/s、2℃/和0.2℃/s不同冷却速度下室温拉伸变形过程微观组织演变及抗拉强度,确定了实验钢在冷却速度下的相变机制,得到Mn-Ti型实验钢随着冷却速度增加,屈服强度、抗拉强度、屈强比显著升高,当冷却速度达到20℃/s时,抗拉强度最高可达到998MPa。(2)Mn-Ti型高强钢控轧控冷工艺后控冷至320℃、280℃、240℃、170℃和100℃进行卷取,观察并研究了试验钢的微观组织对冲击性能的影响,分析了不同卷取温度下多种形态铁素体、位错、M-A岛对钢材冲击性能的控制机制。结果表明,随着试验钢卷取的温度从320℃降到100℃,试验钢微观组织中位错结构和细小M-A岛的多边形铁素体最有利于冲击吸收能量的增加;当板条状铁素体和大尺寸M-A岛出现时,冲击吸收能量下降;特别是较大长度的板条状铁素体形成时,试验钢的冲击吸收能量下降至最小。(3)利用Gleeble-3800热模拟在应变速率为1s-1变形温度在760℃、810℃、860℃、910℃、960℃和860℃下应变速率分别为0.1s-1、1s-1、5s-1、10s-1进行热压缩实验,研究不同应变速率和变形温度热变形参数对Mn-Ti型多相高强钢变形后冷却时相变过程和微观组织特征的影响,以准确地控制变形后的组织,优化生产工艺及微观组织。
[Abstract]:Iron and steel industry is the pillar industry of our national economy. At present, China's iron and steel industry is in the key period of resolving overcapacity. In addition, many domestic and foreign fields of steel also put forward a higher strength. In 21th century, the controlled rolling and cooling process is a new technology. Low carbon microalloyed high strength steel under controlled rolling and cooling control technology has not only achieved obvious results in improving the comprehensive properties of steel, but also has been widely used in iron and steel production. Moreover, controlled rolling and cooling control technology plays an important role in reducing energy consumption and developing green iron and steel materials. At present, it is the research hotspot of iron and steel scholars all over the world. In this paper, low carbon microalloyed Mn-Ti section steel under controlled rolling and controlled cooling process is studied under room temperature tensile deformation, low temperature impact and hot compression. The microstructure and mechanical properties of experimental steel under different experimental parameters were obtained. The evolution process of microstructure and the effect of microstructure on mechanical properties of experimental steel were analyzed. This paper provides a theoretical basis for the formulation of process parameters of controlled rolling and controlled cooling in the actual production process of iron and steel. The specific research contents are as follows: 1) the Mn-Ti type experimental steel is studied at 20 鈩，

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