熱軋帶肋鋼筋論文：低成本高性能HRB400熱軋帶肋鋼生產(chǎn)技術(shù)研究

1、熱軋帶肋鋼筋論文：低成本高性能HRB400熱軋帶肋鋼生產(chǎn)技術(shù)研究【中文摘要】南昌長力鋼鐵股份公司(現(xiàn)方大特鋼科技股份有限公司)生產(chǎn)400MPa級熱軋帶肋鋼筋一直采用20MnSiV鋼坯,成本居高不下,機械性能富余量小,難以適應(yīng)市場要求和南鋼公司發(fā)展的需要。GB1999.2-2007鋼筋混凝土用熱軋帶肋鋼筋中對HRB400熱軋帶肋鋼筋的化學(xué)成分只規(guī)定了上限,沒有規(guī)定下限,即在確保鋼筋性能合格的前提下可自主確定其化學(xué)成分。項目組在對國內(nèi)外先進軋制工藝作了大量調(diào)研工作后,結(jié)合本廠實際設(shè)備和工藝狀況,提出通過鈮微合金化結(jié)合控軋控冷工藝開發(fā)低成本高性能熱軋帶肋鋼筋,獲得成功。本文主要研究內(nèi)容如下：確定了在

2、現(xiàn)有設(shè)備條件下,用高碳低硅低錳低鈮的20MnSiNb鋼坯采用高水壓控制冷卻工藝,細(xì)化晶粒,提高鋼筋強度。在此基礎(chǔ)上,轉(zhuǎn)爐煉鋼可大幅度降低鋼坯中Mn、Nb的含量,以達到降低冶煉成本的。試驗制定了轉(zhuǎn)爐冶煉的化學(xué)成分,并對其進行優(yōu)化,確定了400MPa級鋼筋最佳成分設(shè)計方案為：C:0.20.25%, Mn:1.091.25%, Si:0.450.6%, Nb:0.0060.009%。研究了鋼坯加熱溫度對鋼筋性能的影響,結(jié)合鋼筋力學(xué)性能和現(xiàn)場設(shè)備能力,確定加熱溫度控制在1050最佳。研究了穿水后鋼筋溫度和自回火溫度對鋼筋性能的影響,確定了穿水后鋼筋溫度在500550,自回火溫度在680700的控制冷卻

3、工藝要求。通過優(yōu)化化學(xué)成分,改進工藝參數(shù),提高鋼筋塑性指標(biāo),解決了屈服點不明、塑性指標(biāo)差、橫筋冷彎開裂等現(xiàn)場問題。試驗證明：只要合理地控制各關(guān)鍵工序參數(shù),項目組研發(fā)生產(chǎn)的低成本高強度帶肋鋼筋力學(xué)性能完全可以達到國家HRB400熱軋帶肋鋼筋標(biāo)準(zhǔn)要求,Rm540MPa, ReL400MPa,而且質(zhì)量穩(wěn)定,經(jīng)濟效益十分顯著?！居⑽恼縏he 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.【關(guān)鍵詞】熱軋帶肋鋼筋 低成本 控軋控冷 力學(xué)性能【英文關(guān)鍵詞】hot-rolled ribbed bars low

13、cost controlling the rolling and cooling mechanical properties【目錄】低成本高性能HRB400熱軋帶肋鋼生產(chǎn)技術(shù)研究摘要3-4ABSTRACT4-5第一章 緒論8-231.1 HRB400級熱軋帶肋鋼筋的現(xiàn)狀與發(fā)展8-91.2 HRB400級熱軋帶肋鋼筋的傳統(tǒng)生產(chǎn)工藝9-131.2.1 低溫軋制91.2.2 軋后余熱處理91.2.3 微合金化9-121.2.4 超細(xì)晶粒鋼生產(chǎn)12-131.3 控軋控冷工藝13-181.3.1 控制軋制工藝13-151.3.2 控制冷卻工藝15-181.4 控軋中有害組織對性能的影響18-201.5

14、課題來源及研究內(nèi)容20-231.5.1 課題來源201.5.2 現(xiàn)有工藝狀況與生產(chǎn)20MnSiNb工藝的差距20-211.5.3 課題研究意義21-221.5.4 課題研究內(nèi)容22-23第二章 南鋼棒材廠工藝概況及試驗方案確定23-272.1 南鋼棒材廠概述23-242.2 試驗設(shè)備條件和工藝要點24-262.3 研究方案26-27第三章 HRB400級熱軋帶肋鋼筋成分制定和優(yōu)化27-433.1 HRB400帶肋鋼筋成分試驗與制定27-333.1.1 試驗工藝27-283.1.2 試驗結(jié)果分析與討論28-323.1.3 化學(xué)成分調(diào)整與制定32-333.2 錳、鈮和碳當(dāng)量的影響規(guī)律分析及優(yōu)化33-413.2.1 錳含量對微合金化鋼性能的影響33-343.2.2 碳當(dāng)量對性能的影響34-353.2.3 鈮含量及鋼坯加熱溫度對性能的影響35-393.2.4 鋼水澆注過熱度對性能的影響39-413.3 本章小結(jié)41-43第四章 控軋控冷工藝試驗研究43-584.1 試驗工藝43-444.2 控軋工藝參數(shù)對HRB400鋼筋性能的影響分析與優(yōu)化44-484.2.1 鋼坯加熱溫度的影響分析與優(yōu)化45-474.2.2 終軋前預(yù)穿水對性能的影響分