Activity of reducing steel slag of EAF

Reducing steel slag (RSS) was mainly acquired from five electric-arc furnace (EAF) steelmaking plants (among them, the products of two plants were carbon steel and those of other plants were stainless steel) for research tests. The chemical properties, compound compositions, activities and contents of main expansive compounds were tested. The results showed that the field sampled RSS had a very high crystallinity and hydraulicity with main chemical compositions close to those of Portland cement. It can be known from the study that in case of C/S ratio higher than 2.0, the main compound compositions are C₂S, C₃S, C₂F and f-CaO. However, after the RSS was stored for six months, an obvious variation occurred with potential pre-hydration in RSS, where the SO₃ content was slightly reduced and the compressive activity index was obviously higher than that at the 28th day.     

滚筒渣与热闷渣基础性能研究

为实现钢渣的高效资源化利用,采用X射线荧光光谱（XRF）、X射线衍射（XRD）、扫描电镜（SEM）、粒径分布、安定性、易磨性等检测方法研究了滚筒法、热闷法处理工艺对钢渣基础性能的影响. 研究表明:滚筒渣和热闷渣的主要化学成分和物相组成相差不大,滚筒渣中硅酸二钙(C₂S)、硅酸三钙(C₃S)和铁酸二钙(C₂F)的质量分数较大,且可以较明显的观察到金属铁粒; 与热闷渣相比,滚筒渣中CaO质量分数较大,而 f-CaO质量分数较少.在2.0 MPa饱和蒸汽下进行压蒸试验发现,在相同粒径范围内,滚筒渣的安定性指数普遍大于热闷渣,安定性优异. 采用水泥试验小磨进行粉磨,得到比表面积随粉磨时间延长的特征曲线. 结果发现,在相同的粉磨时间内,滚筒渣的比表面积均小于热闷渣的比表面积,当粉磨时间超过70 min时,滚筒渣的粉磨效率趋于平缓,而热闷渣继续粉磨到110 min时,比表面积增加15.67%,因此滚筒渣的易磨性较差.粒度筛分与压碎值测定试验结果显示,滚筒渣的粒径大部分集中在3~5 mm,热闷渣主要集中在3~10 mm且粒度分布较均匀; 滚筒渣和热闷渣粗细骨料的压碎值均达到Ⅰ类粗细骨料技术指标,可直接用作粗细骨料.     

Ce—Ca、Ce—Mg微合金化钢大线能量焊接热影响粗晶区组织与力学性能研究

研究Ce-Ca、Ce-Mg微合金化低合金钢大线能量焊接热影响粗晶区（CGHAZ）的力学性能、组织结构及夹杂物成分与形态。结果表明,Ce-Ca微合金化钢CGHAZ的力学性能优于Ce-Mg微合金化钢CGHAZ的力学性能;Ce-Ca微合金化钢CGHAZ中Ce、Ca的氧硫复合化合物夹杂物主要呈球状,Ce—Mg微合金化钢CGHAZ中Ce、Mg的氧硫复合化合物夹杂物主要呈扁条状;氧硫化物与奥氏体基体之间弹性模量和热膨胀系数差别大;氧硫化物近旁产生应变场是晶内针状铁素体（IAF）形成的主要控制因素。     

铸态锰钢的成分优化与变质剂选择

通过化学成分的正交试验,得到了铸态锰钢的最佳化学成分范围,经几种变质剂的系统试验,筛选也其适用的RE－Mg-Ba复合变质剂,优化成分的铸态锰钢经变质处理后,得到了在奥氏体基体上弥散分布碳化物的组织,该铸态锰钢具有初始硬度高,加工硬化能力强,足够的冲击韧性和良好的抗磨性等特点。     

低合金高强度钢力学性能与化学成分之间的统计建模与分析

分析了影响钢力学性能的各种化学成分,根据重要性确定了C,Si,Mn,P,S,Alt,Nb,CEQ6等8种化学元素为钢的主要成分,然后据此建立了力学性能与化学成分的多重多元回归模型,并利用双重筛选逐步回归分析表征出对力学性能的显著影响因素,得出了力学性能随影响因素变化的具体变化值.以钢种AM3(大)的实测数据对模型进行了验证.结果表明,五大常规元素的控制精度仍是稳定低合金高强度钢的质量的关键因素,并且杂质对力学性能的影响甚微.     

CSP工艺条件下低碳钢板带材力学性能研究

热轧板带材成品因其内在组织形态及成分不同而呈现较明显的力学性能差异.就包钢薄板坯连续连轧CSP工艺条件下,低碳典型钢种Q235B和SS400显微组织及轧制工艺对材料力学性能的影响进行了实验研究.用数理统计方法建立了工艺参数与产品性能回归数值模型,模型拟合效果较好.     

钢渣作沥青混凝土集料的研究

研究了钢渣的化学成分与稳定性的关系,检测了钢渣的物理力学性能,并进行钢渣沥青混合料配合比设计与性能检验,研究结果表明该钢渣是一种具有优良路用性能的矿质集料,可用于高等级公路面层。     

钢渣作耐磨集料的研究

研究了武钢钢渣的化学成分与稳定性、耐磨性的关系,以及三炼钢尾渣代替部分河沙作细集料对混凝土耐磨性能的影响,研究结果表明该存放期为半年的三炼钢尾渣是一种优质耐磨矿质集料。     

Passivation Mechanism of 316L Stainless Steel in Oxidizing Acid Solution

The compositions and the chemical valence states of elements of 316L stainless steel passive film formed in the oxidizing acid solution were studied by X-ray Photoelectron Spectroscopic (XPS) analysis. The electrochemical polarization curve was measured. The passivation process in the oxidizing acid solution was studied by AC impedance technology. The results indicated that the stable compounds layer was formed on the surface of the sample and the adsorption was the main step in the nitrite solution during passivation process. The catalysis passivation mechanism was put forward according to the experimental results. During passivation process, the water molecule was adsorbed on the surface of the sample at first in the oxidizing acid solution. The oxidizer in the solution played a role as catalyst. The oxide and hydroxide, which could be changed each other and finally formed stable passive film, were generated from adsorbing intermediate under the catalytic action. The mathematical models for predicting the steady polarization curve and the AC impedance spectra at certain conditions have been obtained. The passivation mechanism of 316L stainless steel in the oxidizing acid solution can be interpreted by the catalysis passivation mechanism.     

Q420级铁塔用高强度角钢的开发

通过合理设计化学成份,采用Ⅵ微合金化工艺,优化轧制工艺,开发出输电铁塔用Q420角钢。试制表明:生产的Q420角钢组织细小均匀,力学性能、焊接性能良好,产品完全满足超高压输电线路工程的要求。     

Effect of welding process on the microstructure and properties of dissimilar weld joints between low alloy steel and duplex stainless steel

To obtain high-quality dissimilar weld joints, the processes of metal inert gas (MIG) welding and tungsten inert gas (TIG) welding for duplex stainless steel (DSS) and low alloy steel were compared in this paper. The microstructure and corrosion morphology of dissimilar weld joints were observed by scanning electron microscopy (SEM); the chemical compositions in different zones were detected by en-ergy-dispersive spectroscopy (EDS); the mechanical properties were measured by microhardness test, tensile test, and impact test; the corro-sion behavior was evaluated by polarization curves. Obvious concentration gradients of Ni and Cr exist between the fusion boundary and the type II boundary, where the hardness is much higher. The impact toughness of weld metal by MIG welding is higher than that by TIG weld-ing. The corrosion current density of TIG weld metal is higher than that of MIG weld metal in a 3.5wt% NaCl solution. Galvanic corrosion happens between low alloy steel and weld metal, revealing the weakness of low alloy steel in industrial service. The quality of joints pro-duced by MIG welding is better than that by TIG welding in mechanical performance and corrosion resistance. MIG welding with the filler metal ER2009 is the suitable welding process for dissimilar metals jointing between UNS S31803 duplex stainless steel and low alloy steel in practical application.     

铁碳硼合金中硬相的形成方式、相对量及晶格常数的研究

硼在钢和铸铁中既易偏析,又易形成含B硬相——Fe_2B,Fe_3(C,B)和Fe_(23)(C,B)_6等。在Fe-C-B三元系熔化平衡研究(共6个截面,83个试样)的基础上,选择部分试样进行正常冷却(接近铸造冷却条件)和1050℃加热后(接近平衡条件)的显微组织分析以及X-射线衍射晶体分析,得到化学成分、冷却条件与硬相类型、形成方式、形态之间的关系;在X-射线衍射晶体分析的基础上得出了不同冷却条件下的I/I_0—浓度图,即化学成分与硬相数量之间的关系以及Fe_3(C,B)晶格常数、显微硬度与化学成分的关系。研究结果为简便准确区别不同的含B硬相、合理选择化学成分和热处理工艺提供了重要依据。文中对Fe_(23)(C,B)_6→Fe_3(C,B)+γ-Fe相变对硬相形态的影响等提出了见解。     

复合变质处理高铬铸铁破碎机锤头的研制

介绍了复合变质处理高铬铸铁的化学成分、变质处理工艺、变质处理后高铬铸铁的组织和力学性能的变化以及采用复合变质处理高铬铸铁生产破碎机锤头的生产工艺和使用性能.工业实验表明,复合变质处理高铬铸铁锤头的耐磨性约是高锰钢锤头的4倍.     

易切削钢连铸工艺开发

随着我国机械工业的迅速发展,易切削钢受到越来越多的关注.为了满足日益发展的机械工业和汽车工业对易切削钢产量和质量的要求,国内外各钢铁企业积极开展提高易切削钢质量的相关工作.通过对易切削钢钢种特性的研究,找出了影响易切削钢连铸工艺顺行的关键环节和影响连铸坯质量的主要因素,在立足于原有冶炼设备和轧制设备,不增加投资的情况下,成功开发了易切削钢连铸工艺.     

Effects of laser heat treatment on salt spray corrosion of 1Cr5Mo heat resistant steel welding joints

The surface of 1Cr5 Mo heat-resistant steel welding joint was processed with CO2 laser, and the corrosion behaviors before and after laser heat treatment(LHT) were investigated in the salt spray corrosion environments. The microstructures, phases, residual stresses and retained austenite content of 1Cr5 Mo steel welding joint before and after LHT were analyzed with optical microscope and X-ray diffraction, respectively. The cracking morphologies and chemical compositions of corrosion products after salt spray corrosion were analyzed with field emission scanning electron microscopy(FESEM) and energy disperse spectroscopy(EDS), respectively, the polarization curves were measured on a PS-268 A type electrochemical workstation, and the mechanism of corrosion resistance by LHT was investigated as well. The results show that the passive film of original sample is destroyed owing to the corrosive media penetrating into the subsurface, resulting in the redox reaction. The content of residual austenite in the surface and the self-corrosion potential are increased by LHT, which is contributed to improving the capability of salt spray corrosion resistance.     

利用人工神经网络模型预测Q235B热轧板带力学性能

从某公司的薄板热轧管理机中随机抽取数据,用人工神经网络中的BP网络建立原始化学成分和热轧生产的主要工艺参数与产品力学性能之间的关系,来预测产品的力学性能.离线仿真表明,产品力学性能的预报值与实测值的相对误差很小.抗拉强度预报值与实测值的相对误差有88%不超过±2%,屈服强度预报值与实测值的相对误差有86%不超过±4%,延伸率预报值与实测值的相对误差有78%不超过±6%.     

ZGMn13钢在冲击和压力过程中形变诱发马氏体相变强化机理

对ZGMn13高锰钢的化学成分、金相组织、处理方法以及在冲击、压力过程中形变诱发马氏体相变的机理进行了分析 ,进一步阐述高锰钢耐冲击和耐磨损性能优良的内在原因。     

新型Q460高强度钢材在输电铁塔结构中的应用

为了研究Q460高强度钢材在输电铁塔结构中应用的可行性,结合国内外输电铁塔中高强钢的应用现状,介绍了Q460高强度角钢钢材的化学成分、力学性能,对高强角钢市场供货能力、使用技术经济性、高强钢设计技术参数的选取和焊接工艺等方面进行了研究分析.结果表明,输电铁塔结构中使用Q460高强角钢,既有明显的经济技术效益,又有利于节...     

Controlled Deposition of HAp Mimicking Tooth Enamel

1Introduction Dentalenamelistheoutermostlayeroftheteeth.Thematureenamelcrystalsofthemammaliantoothhave someuniquecharacteristics:enamelcrystalsareextremely elongatedinthec axialdirection,havehighcrystallinityandarehighlyorientedparalleltoeachother[1].Them…     

The precipitation and effect of nano nitrides in HSLC steel

The existing forms of N and Al in HSLC (high strength low carbon) steel produced by TSCR (thin slab casting and rolling process), the precipitation thermodynamics and kinetics of AlN, and its effects on structure and mechanical property are studied. The experimental results show that only a small quantity of nitrogen is combined into AlN in HSLC steel produced by TSCR and most of the nitrogen in steel is still free nitrogen. Aluminum-nitride is mainly precipitated during the period of slow air cooling after coiling, but not during rolling and water cooling. The acid-soluble aluminum has no obvious effect on the grain size and mechanical property of HSLC steel produced by TSCR whose acid-soluble aluminum content is 0.005%–0.043%. The precipitation of AlN is not the main cause of grain refinement of HSLC steel produced by TSCR, nor is AlN the dominating precipitate that has precipitation strengthening effect. The nano nitrides are not pure AlN, but have complex compositions. Supported by the National Natural Science Foundation of China (Grant No. 50334010) and the State Foundation for Key Projects: New Generation of Steels (Grant No. G1998061500)