热轧带肋钢筋论文：低成本高性能HRB400热轧带肋钢生产技术研究

1、热轧带肋钢筋论文：低成本高性能HRB400热轧带肋钢生产技术研究【中文摘要】南昌长力钢铁股份公司(现方大特钢科技股份有限公司)生产400MPa级热轧带肋钢筋一直采用20MnSiV钢坯,成本居高不下,机械性能富余量小,难以适应市场要求和南钢公司发展的需要。GB1999.2-2007钢筋混凝土用热轧带肋钢筋中对HRB400热轧带肋钢筋的化学成分只规定了上限,没有规定下限,即在确保钢筋性能合格的前提下可自主确定其化学成分。项目组在对国内外先进轧制工艺作了大量调研工作后,结合本厂实际设备和工艺状况,提出通过铌微合金化结合控轧控冷工艺开发低成本高性能热轧带肋钢筋,获得成功。本文主要研究内容如下：确定了在

2、现有设备条件下,用高碳低硅低锰低铌的20MnSiNb钢坯采用高水压控制冷却工艺,细化晶粒,提高钢筋强度。在此基础上,转炉炼钢可大幅度降低钢坯中Mn、Nb的含量,以达到降低冶炼成本的。试验制定了转炉冶炼的化学成分,并对其进行优化,确定了400MPa级钢筋最佳成分设计方案为：C:0.20.25%, Mn:1.091.25%, Si:0.450.6%, Nb:0.0060.009%。研究了钢坯加热温度对钢筋性能的影响,结合钢筋力学性能和现场设备能力,确定加热温度控制在1050最佳。研究了穿水后钢筋温度和自回火温度对钢筋性能的影响,确定了穿水后钢筋温度在500550,自回火温度在680700的控制冷却

3、工艺要求。通过优化化学成分,改进工艺参数,提高钢筋塑性指标,解决了屈服点不明、塑性指标差、横筋冷弯开裂等现场问题。试验证明：只要合理地控制各关键工序参数,项目组研发生产的低成本高强度带肋钢筋力学性能完全可以达到国家HRB400热轧带肋钢筋标准要求,Rm540MPa, ReL400MPa,而且质量稳定,经济效益十分显著。【英文摘要】The 400MPa grade hot ribbed bars, produced by Nanchang steel factory, using 20MnSiV as row material for a long period. Its costs still

4、 remain at a high level, and its mechanical properties cant meet the needs of market and development of Nanchang steel factory. In recent years, architectural materials market is complicated and confused, the price of the production changed frequently, the main production in Nanchang steel factory i

5、s screw thread reinforced bar, with the simple breed, it cant adapt to the development of market. So, its imperative to explore the low cost and better mechanical properties hot ribbed bars.In GB 1999.2-2007, there are upper limit in chemical composition of HRB400 hot ribbed bars, but it dont have l

6、ower limit, in the condition of good properties, the manufacturer can design the chemical composition independently. So, Nanchang steel factory prepared to develop low cost hot ribbed bars by controlling the rolling and cooling parameters. In this paper, the strength of hot ribbed bars using 20MnSiV

7、 as material are improved by high pressure controlled cooling process, at the same time, converter furnace smelt can decreased the content of Mn and Nb, also, lower the cost. The chemical composition of the steel was designed,and some developments was made.Finally,best chemical composition of the st

8、eel was cleared as followed C:0.20.25%, Mn:1.091.25%, Si:0.450.6%, Nb:0.0060.009%.The effects of the heating temperature to the property of the steel was investigated, associate with the properties of the products and the capability of the equipments, the most suitable heating temperature should be

9、1050The water cooling equipments are the crucial part, the cooing rates should be 500600s.The effects of the steel temperature and the change of this temperature to the properties of this steel after water cooling was investigated. The temperature of the steel after water cooling was fixed at 500550

10、,the high temperature should be 680700.The works are as follows, design of project, selection and installation of equipment, debugging in locale of production, analysis and sum-up of result. There are a series of problems emerged in the experiment, such as, the yield point are not evident, plastic p

11、roperty is bad, the hot ribbed bars split in the cold bending test. In order to settle these problems, we collected a lot of date and samples, analyzed the effect of different process parameters on the mechanical property, and find the corrective measures.The result is, if the key process parameters

12、 can be controlled properly, the mechanical property of low cost and high strength produced by Nanchang steel factory can meet the national standards, Rm540MPa, ReL400MPa, and the products have stable quality and prominent economic benefits.【关键词】热轧带肋钢筋 低成本 控轧控冷 力学性能【英文关键词】hot-rolled ribbed bars low

13、cost controlling the rolling and cooling mechanical properties【目录】低成本高性能HRB400热轧带肋钢生产技术研究摘要3-4ABSTRACT4-5第一章 绪论8-231.1 HRB400级热轧带肋钢筋的现状与发展8-91.2 HRB400级热轧带肋钢筋的传统生产工艺9-131.2.1 低温轧制91.2.2 轧后余热处理91.2.3 微合金化9-121.2.4 超细晶粒钢生产12-131.3 控轧控冷工艺13-181.3.1 控制轧制工艺13-151.3.2 控制冷却工艺15-181.4 控轧中有害组织对性能的影响18-201.5

14、课题来源及研究内容20-231.5.1 课题来源201.5.2 现有工艺状况与生产20MnSiNb工艺的差距20-211.5.3 课题研究意义21-221.5.4 课题研究内容22-23第二章 南钢棒材厂工艺概况及试验方案确定23-272.1 南钢棒材厂概述23-242.2 试验设备条件和工艺要点24-262.3 研究方案26-27第三章 HRB400级热轧带肋钢筋成分制定和优化27-433.1 HRB400带肋钢筋成分试验与制定27-333.1.1 试验工艺27-283.1.2 试验结果分析与讨论28-323.1.3 化学成分调整与制定32-333.2 锰、铌和碳当量的影响规律分析及优化33-413.2.1 锰含量对微合金化钢性能的影响33-343.2.2 碳当量对性能的影响34-353.2.3 铌含量及钢坯加热温度对性能的影响35-393.2.4 钢水浇注过热度对性能的影响39-413.3 本章小结41-43第四章 控轧控冷工艺试验研究43-584.1 试验工艺43-444.2 控轧工艺参数对HRB400钢筋性能的影响分析与优化44-484.2.1 钢坯加热温度的影响分析与优化45-474.2.2 终轧前预穿水对性能的影响分