穿水冷却生产钢筋的工艺实践

以20MnSi或近似于20MnSi钢坯为原料,用余热处理工艺生产日标SD390和英标460MPa级钢筋,分别对紊流套、夹送辊等进行了改造,调整了水冷段数、水压、上冷床温度,总结出了穿水钢筋合理的化学成分.结果表明,20MnSi用余热处理工艺能生产出高等级钢筋.     

余热淬火/热芯回火工艺——轧钢新技术讲座之九

棒材轧后热芯回火工艺是比利时CRM发明的一项新技术,现已广泛应用于钢筋和棒材的生产中。国内上海钢研所工艺分所于20世纪80年代中期率先研制成功,并应用于K20MnSi和KQ235热轧带肋钢筋生产中,国内称该工艺为热轧钢筋轧后余热处理工艺。其原理是:热轧轧件离开终轧机架后进入水冷箱,通过强力快速冷却使钢筋表面层形成具有一定厚度的淬火马氐体,而芯部仍为奥氏体。当钢筋离开强制快速冷却水箱进入冷床后,芯部的余热向表层扩散,使表层的马氏体自回火。当钢筋在冷床上缓慢自然冷却时,芯部的奥氏体发生相变,形成铁素体和珠光体或奥氏体和珠光体。     

大规格高强度钢筋轧后余热处理工艺探讨

采用20MnSi连铸坯、轧后余热处理工艺生产的大规格（Φ40mm）钢筋外层厚度2．0—3．4mm，过渡层厚度1．7-3．5mm，屈服强度不小于530MPa，抗拉强度不小于610MPa，符合BS4449标准460MPa级钢筋的要求。钢筋的金相组织：外层，回火索氏体；过渡层，索氏体＋珠光体＋铁索体＋贝氏体；心部，贝氏体＋珠光体＋铁索体。试验选定的加热温度为1080-1100℃，终轧速度3．4—3．7m/s冷却方式是管内流水冷却，冷却水量500～660m^3／h，水压0．40-1．0MPa。     

铌微合金化控冷HRB400钢筋的试制

将Nb微合金化技术和控制轧制、控制冷却技术进行综合应用,开发出了具有成本优势的HRB400钢筋。本文介绍了产品开发的技术思路、成分设计、生产工艺路线、冶炼和连铸工艺和轧制工艺。在20MnSi成分基础上,添加0.008～0.028%的Nb,可生产单线轧制的Φ12～25mm HRB400钢筋;添加0.021～0.036%的Nb、0.010～0.027%的Ti,可生产单线轧制的Φ28～32mm和切分轧制的Φ16～20mm HRB400钢筋。轧制时钢筋上冷床温度宜控制为810-870℃。钢筋的组织为铁素体+珠光体或铁素体+珠光体+少量贝氏体,表面无自回火组织。     

400MPa级热轧带肋钢筋控轧控冷工艺应用试验

通过制定合理工艺参数,在生产线上对20MnSi连铸方坯进行了控轧控冷试验。试验结果表明,钢筋表层为回火索氏体+少量铁素体,过渡层为回火索氏体+珠光体+铁素体,半径1/2处为细小的珠光体+铁素体,晶粒度9.5级。轧制速度对控冷效果的影响最为明显,自回火温度对钢筋的组织和性能影响较大。     

轧后余热处理对20MnSi钢组织和性能的影响

通过光学显微镜、扫描电镜及拉伸试验等分析测试方法,研究了轧后余热处理工艺对20MnSi螺纹钢组织及力学性能的影响。研究表明：与传统生产方法相比,轧后余热处理工艺显著改善了20MnSi螺纹钢的组织特征,使其表层为保留马氏体位向的回火索氏体组织,心部为细化的铁素体加珠光体组织,且珠光体相对含量有所增加。通过拉伸实验表明,轧后余热处理工艺可以明显提高20MnSi钢的力学性能。     

钢筋轧后余热处理的研究

介绍了马钢余热处理钢筋产品的试制概况、生产工艺流程以及产品的成分、性能和金相组织情况。以Q235、20MnSi钢坯为试验材料研究了成分、工艺对余热处理钢筋性能的影响,并且研究了钢筋时效时的性能变化,提出了在我国积极推广应用余热处理钢筋的建议。     

英标460B高强度钢筋的开发

介绍了英标460B钢筋的研制情况，通过成分设计和开发QTB余热处理工艺生产出合格的钢筋。研究了钢筋的时效规律，自然时效后屈服强度最大下降30MPa，用人工时效可以模拟自然时效，工艺是将钢筋加热到100℃后，保温2小时。     

超级钢技术在中厚板生产中的应用

采用Q235连铸坯在中板厂2800mm轧机上进行超级钢生产工艺试验,研究了轧制温度、中间坯厚度、待温期间冷却方式及轧后冷却方式对板材组织和力学性能的影响。结果表明,12mm规格Q235板的屈服强度大于370MPa,最高达到397MPa,铁素体晶粒度达到9～9.5级;20mm规格屈服强度可达到330MPa以上,最高达到350MPa,铁素体晶粒度达到9～9.5级。     

英标460级钢筋性能时效的研究

对采用轧后余热处理工艺生产的英标460级钢筋进行不同时间的自然时效后测定其力学性能。结果表明,自然时效后钢筋的屈服强度有较大幅度下降,抗拉强度有小幅度的上升。     

熔炼次数对M17返回料合金成分、组织和性能的影响

实验结果表明,M17铸造高温合金(%:0.16C、8.79Cr、5.79A1、4.93Ti、3.29Mo、15.20Co、0.78V、0.015B、0.073Zr、0.002S、0.001P、0.001 1O、0.001 0N)经25 kg真空感应炉返回重熔后,Si含量随重熔次数的增加而略有增加,合金中主要元素和其它杂质元素S、P、H的含量变化不大,而氧、氮略有增加;合金中初生碳化物由新合金中的草书体逐渐向返回合金块状转变,初生碳化物的遗传性堵塞合金凝固时的补缩通道,使返回料合金的疏松倾向增大,高温塑性下降较大。     

Shijiazhuang will Build the World's Biggest Replacingcopper-with-aluminum Cable Production Base

正Shijiazhuang City will build the world’s biggest replacing-copper-with-aluminum cable production base,the annual output value can reach 100 billion yuan,in the future it will develop replacing-copper-with-aluminum highend industry cluster.This piece of news was learned by the reporter at the Rare Earth highiron Aluminum Alloy[Nonferrous Business Opportunity:Aluminum alloy door]Cable Conductor New Technology Application Seminar held at the provincial capital.     

Chongqing is Preparing to Set Up Nonferrous Metal Exchange,in a Bid to Become the Transit Place of Kazakhstan Copper

正Since the beginning of Chongqing’s upgrading to a municipality directly under the Central Government,Chongqing City has established direct friendly relationship with Almaty,Kazakhstan,and carried out a series of cooperation in commerce and trade,and culture     

Guangxi Baise Extends Industrial Chain to Combat Loss in Aluminum Business

正"For each tonne of aluminum being produced,the upstream enterprise on the aluminum industrial chain will suffer loss about 2000yuan."Said Liang Xiao,Deputy Director of Pingguo Industrial Park Management Committee under the Guangxi Baise City,one of the four major aluminum industry bases in China,on August 11.Extending aluminum     

JOURNAL OF IRON AND STEEL RESEARCH INTERNATIONAL ANNUAL CONTENTS Volume 21(2014)

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Chinalco Straightened Out Copper Assets,and Delegated Stock Equity of Yunnan Copper

正Immediately after the news that Chinalco transferred 58%stock equity of Yunnan Copper Group to its wholly-owned subsidiary China Copper Corporation Limited free of charge was disclosed on July 9,many individual investors couldn’t help but to think:Does it mean China Copper Corporation Limited will assemble assets for overall listing?At present,among main copper business companies under China Copper Corporation     

The Development and Reform Commission Encourages Private Capital to Enter Geological Prospecting Field

正At the press conference recently held by the National Development and Reform Commission under the theme"Deepen Reform in Investment AuditApproval System",when answering questions from reporters,Huang Min,Director of the Department of Fixed Assets Investment of the National Development and Reform Commission,said that in the future it would continue to intensify efforts in geological prospecting,and actively guide social capital to enter this field.     

Guangxi's first Nickel Industry Development Research Report Was Released

正Recently,Guangxi Metallurgical Research Institute,a subsidiary of Guangxi Nonferrous Metals Group,completed survey on laterite and related manufacturers in the region,by combining the current development status of laterite both at home and abroad,it compiled Guangxi’s first"Research Report on the Development of Guangxi Nickel Industrial Chain"which adopted laterite as the study subject.This report expounded on the current     

China’s Major Non-ferrous Metals Imports & Exports(End of September. 2014)

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China's Major Non-ferrous Metals Imports & Exports

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