超高强铁素体/贝氏体双相钢的控轧控冷实验研究

在实验室Φ450 mm轧机上进行了铁素体/贝氏体双相钢（/%:0.22C,0.47Si,2.50Mn,0.05Al,0.02Nb,0.41 Cu）终轧800～860℃的控轧控冷实验。结果表明,实验钢经控轧控冷后,获得以铁素体/贝氏体双相组织为主并含有少量残余奥氏体+马氏体的复相组织。降低终轧温度、加快冷却速度可使铁素体晶粒细化。800℃终轧后层流冷却到560℃,然后空冷到室温的实验钢组织中残余奥氏体含量为11.4%,对强度和韧性的良好匹配贡献很大,其力学性能为:抗拉强度（R_m）1131MPa ,屈强比(R_p0.2/R_m)0.61,伸长率(A₅₀)16%,强塑积(Rm×A₅₀)18096 MPa·%     

含铌微合金化热轧多相钢的控轧控冷工艺

通过热轧试验研究了两阶段轧制+层流冷却、空冷、超快冷的TMCP工艺对高硅铌钢、高硅Nb-Ti钢、低硅Nb-Ti钢显微组织和力学性能的影响。结果表明,控轧控冷后的试验钢含有铁素体、贝氏体、马氏体以及少量残余奥氏体的混合组织。在控轧控冷工艺参数相近的情况下,高硅铌钢、高硅Nb-Ti钢、低硅Nb-Ti钢的抗拉强度依次减小,其伸长率和强塑积依次增大。低硅Nb-Ti钢的伸长率和强塑积分别达到了41%、25 256 MPa.%的最大值。     

C Si Mn Cr Nb钢双相组织性能的柔性控制

 根据C Si Mn Cr Nb试验钢的双道次变形和分段冷却热模拟试验结果,进行了试验钢控轧控冷试验,分析了工艺参数对试验钢组织和性能的影响,获得了具有不同力学性能的铁素体+马氏体或铁素体+贝氏体双相组织。结果表明,试验钢两段轧制分段冷却后550 ℃卷取获得铁素体+马氏体双相组织,屈服强度415 MPa,抗拉强度710 MPa,伸长率23.0％,屈强比0.59。500 ℃卷取得到铁素体加粒状贝氏体双相组织,与550 ℃卷取相比,屈服强度升高35 MPa,抗拉强度降低45 MPa,伸长率略微降低。     

微合金化热轧TRIP钢的工艺模拟

 借助MMS-300热模拟试验机研究了控轧温度区间、终冷温度、贝氏体区等温处理以及冷却路径对微合金化热轧TRIP钢组织演变规律的影响。结果表明,随着控轧温度区间“下调”,组织中的铁素体晶粒越来越细小,铁素体量逐渐增加,残余奥氏体量则先增加后减少。终冷温度升高时,组织中的残余奥氏体量也呈现出先增加后减少的变化趋势,而贝氏体温度范围等温时间的延长使残余奥氏体量增加。相对于“缓冷+快冷”,轧后采用“快冷+缓冷+超快冷”冷却路径更有助于铁素体晶粒的细化和奥氏体的残留。在“快冷+缓冷+超快冷”冷却路径下,当控轧温度区间为900~840℃,缓冷温度范围为710~680℃,贝氏体等温处理制度为450℃×5min时,组织中的残余奥氏体量达到最高值113%。     

薄板坯连铸连轧低温卷取生产双相钢的工业试验

在薄板坯连铸连轧生产线上,利用微合金元素Nb、Ti析出抑制再结晶发生,加工硬化奥氏体加速铁素体相变,轧后连续快速冷却至低温卷取,利用细晶强化和相变强化生产低成本高强度热轧双相钢。在FTSR生产线上进行工业试验。结果表明,在终轧800～820℃,快速冷却至卷取温度300℃以下,可以得到铁素体和马氏体双相组织,屈服强度400MPa以上,抗拉强度超过650MPa,屈强比低于0.70,伸长率大于20%。     

短流程CSP生产线超快冷生产工艺的开发与应用

文章基于短流程CSP生产线,开发了适合热轧双相钢的超快冷生产工艺,并且实现了该生产工艺的工业应用。结果表明:随着终轧温度降低,铁素体晶粒细化,抗拉强度升高;随着中间温度降低,铁素体晶粒细化,抗拉强度降低;获得合理的工艺参数,终轧温度为840℃,中间温度为670℃,卷取温度为170℃。所生产6.0 mm厚度540 MPa级热轧双相钢的显微组织为铁素体和马氏体,屈服强度为330～360 MPa,抗拉强度为560～590 MPa,延伸率为30%～36%,很好地满足了产品需求。     

控轧控冷工艺对X100管线钢组织和性能的影响

通过实验室φ350 mm 4辊轧机对V-Nb-Wi微合金化X100管线钢(%:0.057C、1.84Mn、0.25Mo)进行控轧控冷试验。结果表明,在1 100℃始轧,800～900℃终轧,100～400℃终冷温度下,X100钢的组织为针状铁素体+粒状贝氏体-下贝氏体。降低终轧温度可细化组织,提高钢的强度;降低终冷温度可提高钢的强度,但使钢的韧性降低。X100管线钢的最佳轧制工艺为终轧温度850℃,终冷温度200℃。     

工程机械用高强度钢板控轧控冷工艺的开发

为开发强度级别为６８５ＭＰａ的高强钢板的控轧控冷工艺,研究了终轧温度,未再结晶区累积压下量,终冷温度,冷却速度等工艺参数对钢的显微组织和力学性能的影响。实验结果表明,在控轧控冷条件下,钢的室温显微组织由铁素体和贝氏体组成,贝氏体主要以粒状贝氏体为主,此外,晶粒细化是提高钢的强度和韧性的最有效的手段。     

钛微合金高强钢控轧控冷工艺研究

采用金相显微镜、电子显微镜等手段研究控轧控冷工艺对Ti微合金化高强钢的组织和性能的影响。结果表明:在低温终轧(800℃)、600℃保温1 h的试验钢的屈服强度和抗拉强度最高,分别为670.7 MPa和752 MPa。高温终轧(1 030℃)的试验钢组织主要为准多边形铁素体、针状铁素体和粒状贝氏体,组织粗大;低温终轧(800℃)的组织主要为多边形铁素体,晶粒较细小。在600℃保温1 h的试验钢中存在大量的纳米尺寸TiC粒子,沉淀强化效果明显,未在600℃保温1 h的试验钢中,TiC的析出受到限制,沉淀强化效果明显减弱。     

贝氏体等温温度对超高强冷轧TRIP钢组织性能的影响

将C-Si-Mn钢加热至800℃保温120 s后,分别快速冷却至350～410℃保温600 s以模拟贝氏体等温转变工艺。通过扫描电镜(SEM)和拉伸测试的方法研究了贝氏体等温温度对超高强相变诱导塑性钢(TRIP钢)微观组织和力学性能的影响规律。结果表明,冷轧TRIP钢的微观组织由铁素体、贝氏体、马氏体和残余奥氏体组成;贝氏体和残余奥氏体形成于等温转变阶段,而马氏体形成于等温后的终冷阶段。随着贝氏体等温温度增加,固溶C原子扩散系数提高,促进残余奥氏体中碳化物的析出。因此,奥氏体中的平均固溶C含量降低,使得TRIP钢残余奥氏体分数降低,马氏体体积分数增加。贝氏体等温温度由350℃增加至410℃时,TRIP钢屈服强度由720 MPa降低至573 MPa,抗拉强度由1 195 MPa提高至1 312 MPa,伸长率A_(80)由17.8%降低至12.5%。贝氏体等温温度为350℃时,冷轧TRIP钢具有优良的综合力学性能,强塑积达到21 270 MPa·%。     

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。     

China's Major Non-ferrous Metals Imports & Exports

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Zinc Production by Province in 2014

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80% of Chinese Firms Purchasing Overseas Mines Ended up in the Red

<正>Minmetals Resources acquired the world’s largest copper mine under construction for USD5.85 billion.One after another,listed companies Jien Nickle,China Molybdenum and Chihong Zinc and Germanium raised money to get involved in overseas mining projects…SOEs and private enterprises are engaged in a frenzy of overseas mine purchasing.A reporter with Economic     

Copper Processing Profit Dropped Sharply,Copper Consumption Will Face Impact in the Second Half of the Year

正Judging from China’s copper consumption field,the biggest consumption unit is electric power,which accounts for 47%of total consumption;it is followed by light industry sector,including household electrical appliance,machinery,durable goods and hardware etc,which accounts for 22%of total consumption;followed by transportation field,     

Central Geological Prospecting Fund Newly Added 16.47 Million Tonnes of Bauxite in 2013

正In 2013,the Central Geological Prospecting Fund(CGPF)Project newly discovered 15 ore fields,including 3 large above ore fields,and 5medium sized ore fields.The reporter learned from the recently published"Annual Report of Central Geological Prospecting Fund Project(2013)"that,from 2006 to 2013 the CGPF     

Manufacturers of Copper Tube for Central Air Conditioner Use Face Mounting Pressure in the Final Quarter of the Year

正This year,the investment growth rate of real estate industry continued to slow down,sold area of commercial housing also dropped significantly,which brought huge pressure to the domestic air conditioning manufactures.In the first half of the year,by relying on high growth in national financial expenditure,along with investment in public infrastructure     

Xinjiang Ranks No.1 in Production of Primary Aluminum in China

正Kang Yi,Honorary Chairman of China Nonferrous Metals Industry Association,said recently at the Forum on Development of the Non-ferrous Metals Industry in Central and Western China held in Zhengzhou that,as more and more electrolytic aluminum factories in Xinjiang came into operation,the electrolytic aluminum output of Xinjiang had reached2,275,000 tons in the first 7 months this year,     

Shenhuo Coal Industry and Electricity Power Completed800,000 t/a Aluminum Project in Xinjiang

正"Xinjiang project has been completed according to schedule,but total completion and total start of production are two different concepts,after completion it still needs a gradual process of reaching production target."On the morning of November 3,Shenhuo Coal Industry and Electricity Power told investors the above statement on the investor interaction platform.     

Guangdong Metal Transaction Center has Become the Second Largest Precious Metal Transaction Platform Nationwide

正The reporter learned from Guangdong Province Precious Metal Transaction Center that in 2013the Center maintained healthy development momentum,and had become the second largest precious metal transaction platform in China in terms of market size;currently Guangdong is quickening steps of financial innovation for the Center,aiming to build a transaction center with international core competitiveness.