Prologue——In memorial to Prof. Guang-Xian Xu

<正>Prof.Guang-Xian Xu,the Editor-in-Chief of Journal of the Chinese Society of Rare Earths(JCSRE,in Chinese)and Journal of Rare Earths(JRE,in English),was a distinguished chemist and educator of China.He was a respected presiding figure in the area of rare earth science in China,and an eminent pioneer in the realm of science,technology and industry of rare earths in the world.Prof.Xu was born in Shaoxing,Zhejiang Province on November 7,1920.He received his B.S.     

Influence factors of capacity loss after short-time standing of metal-hydride electrode and its EIS model

Considerable irreversible capacity loss was observed after the electrode standing at small state-of-charge (SOC) for only a short term. Influence of SOC, standing time and the replacement elements of LaNi5-type hydrogen storage alloys to standing was discussed. Charge-transfer resistance, exchange current density (I0 ), and hydrogen diffusion coefficient were determined based on the study of electrochemical impedance spectrum (EIS), linear polarization (LP) and constant potential step (CPS), respectively. The oxidation of metal Ni on the alloy surface after standing was responsible for the rapid deterioration of capacity, charge-transfer resistance and I0 . Galvanostatic, LP, EIS and CPS measurements suggested the presence of an oxide and/or corrosion layer on the alloy surface of raw material and electrode after standing at 0% SOC for 2 d. It was proved that the first small semicircle in high-frequency region of EIS was related to this layer. Novel EIS model in metal hydride electrode was proposed accordingly.     

时代的挽歌——给艾米莉的玫瑰中艾米莉的形象分析

William Faulkner is an American writer with high reputation, born in a decaying Southern plantation family during the American Civil War.The background of most of his works is the South of America.In his works, he emphasizes the Southern topic and Southern consciousness.There is blood and tears between the lines of his stories.     

Corrosion Behavior of Ferritic/Martensitic Steels CNS-I and Modified CNS-II in Supercritical Water

 The corrosion behaviors of CNS-I and modified CNS-II were evaluated by exposing to superciritical water (SCW) at 550 ℃ and 25 MPa with a dissolved oxygen concentration of 200×10-9 for up to 1000 h. Detailed corrosion results of these two alloys were provided, including the growth rate of the oxide scales, microstructure of the oxide scales, distribution of phases and alloying elements. The mass gains of CNS-I and modified CNS-II were 60973 mg/dm2 and 45942 mg/dm2, respectively, after exposing to SCW for 1000 h. A duplex oxide scale with an outer porous magnetite layer and an inner relatively dense magnetite/spinel-mixed layer was identified on CNS-I and modified CNS-II after the test. The oxide scales were rather porous at the beginning of the test but the porosity decreased with increase of the exposure duration. It was found that Fe was enriched in the outer oxide layer, Cr was enriched in the inner oxide layer and O existed at a very high concnetration in the whole oxide scale. Other alloying elements such as Mo, W, Mn were depleted from the outer oxide layer and showed slightly enrichment in the inner oxide layer. The distributution of Ni was different from other elements, it was enriched in the interface bewteen the base metal and the oxide scale and depleted in the outer and inner oxide layers.     

Evolution of microstructure,mechanical and magnetic properties of electrodeposited 50%Ni-Fe alloy foil after thermal treatment

In order to expand the application of the electrodeposited Ni-Fe alloy foil,their mechanical and magnetic properties were studied after heat treatment.The development of grain growth during annealing was in-situ online investigated using a heating stage microscope,and the texture was analyzed via X-ray diffraction(XRD)and electron back-scattered diffraction(EBSD).The results indicated that abnormal grain growth usually occurred during annealing at 1000-1050°C.The{111}oriented grains preferentially grew as the annealing temperature and holding time increased.The plasticities of the electrodeposited Ni-Fe alloy foils after heat treatment were better than those of the original samples.The excellent ductility was obtained without a loss in magnetic properties after annealing at 1100°C for 6h.     

Effect of Hot Band Annealing Processes on Microstructure,Texture and r-Value of Ferritic Stainless Steel

The effect of hot band annealing processes,namely simulating batch annealing and continuous annealing,on microstructure,texture,grain boundary character and r-value of ferritic stainless steel was investigated.The hot band displayed a highly elongated ribbon-like structure and a pronounced deformation texture.The fully recrystallized grains were observed after continuous annealing while the "typical" hot rolled structure was remained after batch annealing.Also,the α-fibre texture formed during hot rolling almost disappeared after continuous annealing and a weak γ-fibre texture was obtained.By contract,the α-fibre texture remained very stable after batch annealing.After cold rolling and recrystallization annealing,the favorable γ-fibre texture was achieved in the continuous annealed steel.Instead of forming the γ-fibre texture,the recrystallization texture was notably shifted toward {223}582 in the batch annealed steel.Finally,the improvement in drawability with high r-value and low Δr-value were also displayed in sheet through the initial continuous annealing process.     

Effect of Heat Treatment on Corrosion Behaviour of Amorphous Metal Fibers

Amorphous metal fiber has high corrosion resistance and excellent mechanical properties, making it a kind of good material for reinforcing concrete matrix. The effect of heat treatment on the corrosion behaviour of Fe73- Cr6C9Si1P11 amorphous metal fibers in 0.5 mol/L He SO4 solution was investigated by electrochemical polarization analysis. Differential scanning calorimetry （DSC） was used to measure the thermal properties. The evolution of the crystallization process after heat treatment was identified by X-ray diffraction （XRD）. The results show that the α- Fe, Fe2 P and Fea P crystalline phases individually precipitate in the amorphous matrix with increasing annealing temperature. The as prepared amorphous sample shows high corrosion resistance with a lower passivation current density and a wider passive region. The corrosion resistance dramatically decreases after the annealing temperature is higher than 400 ℃.     

Effects of calcium treatment on non-metallic inclusions and magnetic properties of non-oriented silicon steel sheets

Based on the industrial production of non-oriented silicon steel,calcium treatment by CaSi wire feeding during the RH refining process was studied.The thermodynamics of CaS inclusion formation was analyzed,and the morphology and the size distribution were observed.Furthermore,the change in inclusion characteristics after calcium treatment and the effect of calcium treatment on magnetic properties were discussed.The results show that the formation of MnS and AlN inclusions were restrained,and the aggregating,floating and removing of microinclusions after calcium treatment were effectively promoted.The cleanliness of liquid steel was obviously increased.The main type of inclusions was single phase of CaO,with some complex inclusions composed of CaO,SiO2 and MgO.No CaS inclusion was observed after an appropriate calcium treatment.The size of all inclusions was distributed in the range of 2-20 μm,and the number was about 1.8×105 /mm3.In addition,as an increasing amount of calcium was added,the core loss gradually decreased to a stable level,and the magnetic induction decreased quickly after a slow increase.The optimal calcium treatment mode depends on the chemical composition of steel.     

The Effect of Nb on Mechanical Properties of Quenching and Partitioning Steels

In order to study the effect of alloy elements on mechanical properties of quenching and partitioning steels,the Q and P heat treatments on different chemical composition steels were carried on in lab.The tensile test results indicated the strength of Nb+Ti-bearing steel was not increasing as expected,but lower than that of the Nb+Ti-free steel,and the elongation was raised to 26% from 9%.The Nb+Ti-bearing steel microstructures after tensile test were detected by TEM and found a certain amount of twins in the deformed microstructure while the deformed microstructure mainly was lath martensite in Nb+Ti-free steel,which means the addition of Nb and Ti elements could cause the twinning induced plasticity by inhibiting the phase transformation from austenite to martensite.Based on above analysis,adding trace Nb element could greatly increase the stacking fault energy of the retained austenite,which is beneficial to the formation of twins,and the formation of twins would lower the strength slightly and raise the elongation drastically.     

Preface

正25 years ago,Baosteel’s 1st cold rollingmill was put into production.Since then,Baosteel has been exploringits own wayto promote technology progress.In the beginning,the companyimported the core technology from abroad,and after years of assimilation and absorption,it graduallyachieved independent innovation.So far,Baosteel has always been leading the     

Practice for Extending Blast Furnace Campaign Life at Wuhan Iron and Steel Corporation

One of the problems encountered in 60＇s to 80＇s of 20th century in China＇s steel industry was short life of blast furnace shaft as well as the excessive erosion of blast furnace hearth. A series of research work was carried out in order to extend blast furnace campaign life. The concept of research and development was integrated in the construction of BF （blast furnace） No. 5 at WISCO （Wuhan Iron and Steel Corporation）, and in October, 1991, the BF No. 5 was blown in. The blast furnace has worked smoothly for more than 15 years without any medium repair even guniting. It is expected that the campaign life of BF No. 5 would be longer than 16 years with a production over 11 000 t per unit inner volume （m^2）. A new blast furnace with an inner volume of 3 400 m^3 is under construction, and is designed with a campaign life of 20 years without any medium repair. The campaign life of blast furnaces in China has been extended in recent years.     

Influence of neodymium addition on microstructure,tensile properties and fracture behavior of cast Al-Mg2Si metal matrix composite

The influence of Nd on the microstructures,tensile properties and fracture behavior of cast Al-18 wt.%Mg2Si in situ metal matrix composite was investigated.Experimental results showed that,after introducing a proper amount of Nd,both primary and eutectic Mg2Si in the Al-18 wt.%Mg2Si composite were well modified.The morphology of primary Mg2Si was changed from irregular or dendritic to polyhedral shape,and its average particle size was significantly decreased from 47.5 to 13.0 μm.Moreover,the morphology of the eutectic Mg2Si phase was altered from flake-like to a thin laminar,short fibrous or dot-like structure.Tensile tests revealed that Nd addition improved the tensile strength and ductility of the material.Compared with those of unmodified composite,the ultimate tensile strength and percentage elongation with 0.5% Nd were increased by 32.4% and 200%,respectively.At the same time,Nd addition changed the fracture behavior from brittle to ductile.     

Population Evolution of Oxide Inclusions in Ti-stabilized Ultra-low Carbon Steels after Deoxidation

Population density function(PDF),which can eliminate the arbitrariness caused by the choice of the number and the size of bins compared to the well-used histograms,was introduced to analyze the amount of inclusions.The population evolution of oxide inclusions in forms of PDF in Ti-stabilized ultra-low carbon steels after deoxidation during industrial RH refining and continuous casting processes was analyzed using an automated SEM-EDS system.It was found that after deoxidation till the early stage of casting,the alumina inclusions exhibited a lognormal PDF distribution,and three factors including the existence of a large amount of alumina clusters,the generation of alumina from the reduction of Al-Ti-O inclusions and the reoxidation of molten steel were estimated as the reasons.The shape parameterσwas high after deoxidation and then decreased after Ti treatment,indicating that in a short period after deoxidation,the size of alumina inclusions was widely distributed.After Ti treatment,the distribution of inclusion size was more concentrated.The scale parameter mdecreased with time during the whole refining process,indicating that the proportion of large inclusions decreased during refining.Contrarily,the Al-Ti-O inclusions presented a fractal PDF distribution except at the end of casting with fractal dimension Dof 4.3,and the constant of proportionality C decreased with time during RH refining and increased during casting process.The reoxidation of steel by slag entrapped from ladle was considered as the reason for the lognormal PDF behavior of Al-Ti-O inclusions at the end of casting.     

Effect of deep cryogenic treatment on martensitic lath refinement and nano-twins formation of low carbon bearing steel

The effect of heat treatment and deep cryogenic treatment on microstructural evolution of low carbon martensitic bearing steel was investigated.The experimental results showed that the lath martensite was obtained by quenching and a few twins as substructures formed in some martensitic laths.The rudiment of sub-interfaces of martensitic lath was formed in the highdensity dislocation regions after deep cryogenic treatment;meanwhile,the number of twins increased,especially in the highdensity dislocation regions.This phenomenon is due to the increase in internal stress caused by cryogenic treatment.After tempering,the rudiment of sub-interface further evolved into the martensitic lath boundary,and thus the original martensitic laths were refined.The twins formed by cryogenic treatment did not disappear after tempering.In addition,small quantities of annealing twins formed in tempering process.Martensitic laths morphology and substructures in different stages of the heat and deep cryogenic treatment were observed by tninsmission electron microscopy.     

Austempering of Hot Rolled SiMn TRIP Steels

 The austempering after hot rolling in hot rolled Si Mn TRIP (transformation induced plasticity) steels was investigated. The mechanism of TRIP was discussed through examination of the microstructure and the mechanical properties of this kind of steel. The results showed that the strain induced transformation to martensite of retained austenite occurs in hot rolled Si Mn TRIP steels. The sample exhibited a good combination of ultimate tensile strength and total elongation when it was held at the bainite transformation temperature after hot deformation. The stability of retained austenite increases with an increase in isothermal holding time, and a further increase in the holding duration resulted in the decrease of stability. The mechanical properties were optimal when holding for 25 min, and tensile strength and total elongation reached the maximum values (774 MPa and 33%, respectively).     

Interaction Between Elements Nb and Mo During Precipitation in Microalloyed Austenite

Thermo-simulation test and transmission electron microscopy (TEM) have been used to investigate the interaction between the microalloying elements Nb and Mo within the precipitates during relaxation after austenite deformation of C-Ti-Mo steel and C-Nb-Mo steel.The experimental results demonstrated that the austenitic structure was preserved both in C-Ti-Mo steel and C-Nb-Mo steel even if they were relaxed for 1000 s after deformation at 850 ℃.The strain-induced precipitate occurs in two kinds of steel.Through the energy spectrum analysis,it was found that the precipitates were Ti(C,N) and Mo-bearing Nb(C,N) respectively and there exists a strong affinity of Mo for Nb with in the precipitates.Mo atoms would enter the lattice of Nb(C,N) particles probably after Nb(C,N) formation.     

Effect of annealing treatment on the anti-pulverization and anti-corrosion properties of La0.67Mg0.33Ni2.5Co0.5 hydrogen storage alloy

The La0.67Mg0.33Ni2.5Co0.5 hydrogen storage alloy was prepared by the vacuum intermediate frequency induction furnace followed by annealing treatment. The pulverization degree of both the as-cast and annealed alloy powders after gaseous hydriding and dehydriding cycle was investigated and the discovery was that annealing treatment could hardly ameliorate their anti-pulverization ability. The element content of La, Mg, Ni and Co existing in electrolyte before and after the electrochemical cycles by using ICP-AES technology was also analyzed and it showed that a large amount of La and Mg were dissolved in the electrolyte, but the amount of dissolution for La and Mg significantly declined when the alloy was annealed. The XRD analysis revealed that all the alloys consisted of two main phases AB3 and AB2 and a residual phase AB5 while annealing treatment made the AB2 phase decrease slightly. Furthermore, the anti-corrosion abilities of various elements in different phases of the as-cast and annealed alloy samples were studied by analyzing the element(La, Mg, Ni, Co) change with the corrosion time in phases AB3 and AB2 by means of EDS. It turned out that the element of La was mainly corroded out from the phase AB2 while not easily from the phase AB3. However, the element of Mg was both easily corroded out from the phases AB2 and AB3, but the corrosion was more obvious in the phase AB3. Therefore, annealing improved the anti-corrosion performances of La and Mg in the phase AB2.     

SHANGHAI METALS EXCHANGE

The membership and client mix of Shang-hai Metals Exchange have changed agreat deal after five years progress sinceits founding in 1992.The stake of state—owned members was     

Effect of LaCrO_3 coating on high temperature oxidation of type 316 stainless steel

A dense and conductive LaCrO3 coating was prepared on type 316 stainless steel (316 SS), aiming at exploring its potential appli-cations in SOFC and in other high temperature environments. Powder of LaCrO3 with perovskite structure was synthesized by sol-gel method. LaCrO3 coating on 316 SS substrate was obtained by slurry coating technique. The microstructure of the coating on 316 SS after sintering in air at 800 and 900 ℃ for 200 h was characterized. The effect of LaCrO3 coating on oxidation resistance of the steel in air was also investi-gated. The results showed that the coating was adhesive to the substrate and improved greatly the oxidation resistance of the alloy.     

Mechanism of Effect of Microwave Modification on Pulverized Coal Combustion Properties

The mechanism of microwave modification on facilitating the combustion properties of pulverized coal(PC)was investigated.Experimental researches on granularity and functional group as well as combustion properties of PC before and after modification were carried out.Micromorphology observation indicated that the size of PC particles was relatively small,which was in accordance with the results of granularity analysis of PC.FT-IR(Fourier-transform infrared)spectra of two PCs indicated that the proportion of the functional groups with high activity increased after microwave irradiation.Furthermore,no valid effect of microwave was found on carbon matrix except small variations in PC particle size,which only led to subtle improvement in combustion of residual coke.Activation energies of Yungang and Yangquan PCs in temperature zone between 450-650℃ were reduced by 12.00%and 10.13%,respectively,which meant that microwave modification might effectively facilitate the combustion properties of PC.Nevertheless,decrease in activation energies of residual cokes was 3.56%and 3.67%respectively,which was subtle and can be regarded as the result of smaller particle size produced by microwave irradiation.