终轧温度对GCr15轴承钢网状碳化物析出的影响

研究了终轧温度(750～900℃)和成品规格(Φ12 mm和Φ5.5 mm)对GCr15轴承钢网状碳化物析出的影响。结果表明,当轧制规格为Φ12 mm、终轧温度为800℃时,碳化物网状级别最低,为1.5,终轧温度降至750℃时,碳化物网状级别增加至2.0;当轧制规格为Φ5.5 mm、终轧温度为850℃时,碳化物网状级别最低,为1.5,终轧温度在800℃时碳化物网状级别又升高至2.5。小规格轧材终轧温度过低,不利于网状碳化物析出的抑制,最佳终轧温度与轧制规格有关。     

提高GCr15轴承钢线材预精轧温度的研究

 通过提高GCr15轴承钢φ10mm线材预精轧温度的工业试验,得到了网状碳化物少的细片状珠光体组织,利用实验室热模拟的方法对工业试验现象做了进一步分析。结果表明：当预精轧温度为944℃时,试验钢网状碳化物的析出时刻全部处于快速冷却阶段,球化退火后渗碳体颗粒均匀细小,网状级别可降低至1.5级,布氏硬度为202.72,强韧性能均较高,满足GB/T18254－2002《高碳铬轴承钢》和实际生产对GCr15轴承钢退火材的要求。     

终轧温度和冷却工艺对Φ36mm GCr15轴承钢网状碳化物的影响

试验研究了终轧905~930℃,空冷,终轧905~930℃,穿水返红至675~707℃,终轧845~870℃,穿水返红至661~698℃对Φ36 mm GCr15轴承钢棒材网状碳化物的影响。结果表明,轧后空冷的GCr15轴承钢棒材的网状碳化物级别较高为3级;轧后棒材经穿水后返红温度为661~707℃时,网状碳化物为1.5~2.5级,能满足冷加工用途GCr15轴承钢的要求(网状碳化物≤2.5级);低温精轧和降低终轧温度能明显改善GCr15轴承钢热轧材的网状碳化物。     

轧制工艺对GCr15显微组织的影响

通过生产试验研究了轧制工艺对GCr15显微组织的影响。结果表明,通过低温精轧和轧后快冷,二次碳化物析出少且呈零星状分布,珠光体组织细小,球化退火后,球化效果最好。     

热变形工艺对100Cr6轴承钢线材网状碳化物的影响

利用热膨胀仪、热模拟试验机、金相显微镜、场发射扫描电镜等测定了100Cr6轴承钢的CCT曲线，试验研究了热压缩及控轧控冷对网状碳化物析出行为的影响。结果表明：第二道次压缩温度从850℃降低至700℃时，奥氏体再结晶细化向未再结晶转变，二次碳化物逐步由晶界封闭网状向半封闭条状、短杆状再向沿拉长的奥氏体晶界链状转变，750～800℃内变形碳化物细小、分散；Φ10 mm 100Cr6线材采用910℃降至770℃温度控轧+快速冷却工艺，其热轧态、球化退火及淬回火后碳化物分布均匀性逐步提升，奥氏体晶粒由8.0级细化至10.0级，晶界碳化物由封闭网状向断续条状转变，平均厚度从0.54μm降低至0.11μm,网状级别由3.0级占比33%降低至≤2.0级占比100%,可缩短球化退火时间及提高轴承的疲劳寿命。     

用超快速冷却新工艺生产GCr15轴承钢

 通过对GCr15轴承钢高温终轧后进行冷却速度大于100 ℃/s的超快速冷却试验,研究了轧后不同冷却工艺制度对组织形态和网状碳化物的影响,结果表明,高温终轧后进行超快速冷却可抑制网状碳化物析出,发生伪共析转变而得到细片层间距的珠光体型组织——索氏体,并促进珠光体形核和减小碳原子扩散能力,达到细化晶粒的目的,得到利于球化退火的预备组织。     

直径34—55mm轴承钢棒材轧后控制冷却与快速球化工艺研究

本文对大断面轴承钢的轧后快冷工艺和控制冷却机理及快速球化退火工艺进行了研究,该工艺可降低轴承钢网状碳化物级别、缩短球化退火时间、降低硬度、提高疲劳寿命,为设计快速冷却设备及水冷工艺提供了依据。     

超快冷技术在轴承钢网状碳化物控制上的应用

河钢宣钢针对轴承钢产品出现的网状碳化物问题,引进了穿水冷却工艺,并实施了GCr15轴承钢轧后快速冷却。通过优化冷却工艺,GCr15轴承钢Φ22～32 mm产品的网状级别≦2. 0级,小规格轴承钢网状碳化物均达到国家标准要求。     

连轧后水冷工艺对 GCr15 轴承钢 Ф60 mm 棒材网状碳化物的影响

通过调节三组水箱高压喷嘴冷却水的强度(轧制速度1.48 m/s,喷嘴内径80 mm,精轧前1#水箱水压≤0.3 Mpa,精轧后2#水箱水压≥1.0 Mpa,3B水箱水压≥1.0 Mpa),控制Ф60 mm GCr15轴承钢终轧温度950℃,喷水后返红温度为680 ℃,使成品材网状为1.5～2.0级,稳定达到标准要求.     

原始组织及退火工艺对SCM435盘条退火行为的影响

分析了低温轧制工艺、低温+缓冷工艺及正常轧制工艺生产的SCM435盘条的显微组织,研究了不同原始组织及退火工艺对SCM435碳化物球化行为的影响。研究结果表明:低温轧制工艺得到的多边形铁素体、珠光体、贝氏体及少许马氏体组织不利于获得均匀分布的球状珠光体;加热温度、加热时间、等温温度及等温时间同样对碳化物球化有较大影响。试验研究得出SCM435退火合适工艺参数:加热温度760℃,保温1.5 h,并随炉冷却到720℃保温5 h,然后随炉冷却到550℃以下出炉空冷。     

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)

正~~     

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)

正~~     

China's Major Non-ferrous Metals Imports & Exports

正~~