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Effects of pre-strain and baking parameters on the microstructure and bake-hardening behavior of dual-phase steel

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International Journal of Minerals,Metallurgy and Materials 2014年第8期21卷 766-771页

作者： Chun-fu Kuang Shen-gen zhang Jun Li Jian Wang Hua-fei Liu School of Materials Science and Engineering University of Science and Technology Beijing Research Institute Baoshan Iron and Steel Co. Ltd.

In a typical process, C-Mn steel was annealed at 800℃ for 180 s, and then cooled rapidly to obtain the ferrite-martensite microstructure. After pre-straining, the specimens were baked and the corresponding bake-hardening （BH） values were determined as a function of pre-strain, baking temperature, and baking time. The influences ofpre-strain, baking temperature and baking time on the microstructure evolution and bake-hardening behavior of the dual-phase steel were investigated systematically. It was found that the BH value apparently increased with an increase in pre-strain in the range from 0 to 1%; however, increasing pre-strain from 1% to 8% led to a decrease in the BH value. Furthermore, an increase in baking temperature favored a gradual improvement in the BH value because of the formation of Cottrell atmosphere and the precipitation of carbides in both the ferrite and martensite phases. The BH value reached a maximum of 110 MPa at a baking temperature of 300℃. Moreover, the BH value enhanced significantly with increasing baking time from 10 to 100 min.

关键词： dual-phase steel pre-strain baking treatment microstructure hardening

Crystallization mechanism of glass-ceramics prepared from stainless steel slag

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Rare Metals 2018年第5期37卷 413-420页

作者： Wen-Di Fan Qiang-Wei Yang Bin Guo Bo Liu Shen-gen zhang Institute for Advanced Materials and Technology University of Science and Technology Beijing

Glass-ceramics have been prepared by using stainless steel slag, fly ash and coal fly ash that were figobtained from industrial solid waste. The crystallization behavior and mechanical characterization of the glass-ce-ramics with different （CaO ＋ MgO）/（SiO2 ＋ Al2O3） content ratios were studied. While the basicity decreases from 1.2 to 0.9 cm^-3, the bridge oxygen content increases from 1.18 ~ 10^21 to 1.34 ~ 10^21 cm^-3. According to the deconvolution of Raman spectra, the relative abundance of the stretching of Si-Onb bond （Q^n units） can be obtained. The increase in the Q^3 units dominates the polymerization in the process of decreasing basicity. This change in bonding is demonstrated to lead to polymerization of the glass network and the increase in crystallization activation energy from 336.0 to 360.7 kJ·mol^-l. The results demonstrate that the production of the glass-ceramics from industrial steel slag, fly ash and coal fly ash is cost-effective and offers advantages over other production methods.

关键词： Glass-ceramics Stainless steel slag Augite

Preparation and properties of thermal insulation coatings with a sodium stearate-modified shell powder as a filler

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International Journal of Minerals,Metallurgy and Materials 2017年第10期24卷 1192-1199页

作者： Qiang Tang Ya-mei zhang Pei-gen zhang Jin-jie Shi Wu-bian Tian Zheng-ming Sun Jiangsu Key Laboratory of Construction Materials School of Materials Science and Engineering Southeast University Nanjing 211189 China Jiangsu Key Laboratory of Advanced Metallic Materials School of Materials Science and Engineering Southeast University Nanjing 211189 China

Waste shell stacking with odor and toxicity is a serious hazard to our living environment. To make effective use of the natural resources, the shell powder was applied as a filler of outdoor thermal insulation coatings. Sodium stearate(SS) was used to modify the properties of shell powder to reduce its agglomeration and to increase its compatibility with the emulsion. The oil absorption rate and the spectrum reflectance of the shell powder show that the optimized content of SS as a modifier is 1.5wt%. The total spectrum reflectance of the coating made with the shell powder that is modified at this optimum SS content is 9.33% higher than that without any modification. At the optimum SS content of 1.5wt%, the thermal insulation of the coatings is improved by 1.0℃ for the cement mortar board and 1.6℃ for the steel plate, respectively. The scouring resistance of the coating with the 1.5wt% SS-modified shell powder is three times that of the coating without modification.

关键词： heat insulation coatings shell powder sodium stearate scrub resistance

Spatial and Temporal Distributions of Atmospheric CO2 in East China Based on Data from Three Satellites

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Advances in Atmospheric Sciences 2020年第12期37卷 1323-1337页

作者： Bozhen LI gen zhang Lingjun XIA Ping KONG Mingjin ZHAN Rui SU Jiangxi Ecological Meteorology Center Nanchang 330096China State Key Laboratory of Severe Weather&Key Laboratory of Atmospheric Chemistry of China Meteorological Administration Chinese Academy of Meteorological SciencesBeijing 100081China Jiangxi Atmospheric Detection Technology Center Nanchang 330096China

East China(23.6°–38.4°N,113.6°–122.9°E)is the largest developed region in *** on CO2 products retrieved from the Greenhouse Gases Observing Satellite(GOSAT),the spatial and temporal distributions of CO2 mixing ratios in East China during 2014–17 are discussed,and the retrieved CO2 from AIRS(Atmospheric Infrared Sounder)and OCO-2(Orbiting Carbon Observatory-2),as well as WLG(Waliguan)background station observations,are compared with those of *** annual CO2 retrieved from GOSAT in East China ranged from 398.96±0.24 ppm in 2014 to 407.39±0.20 ppm in 2017,with a growth rate of 2.82±0.15 ppm yr^−1,which were higher than in other regions of *** seasonal cycle presented a maximum in spring and a minimum in summer or *** values were mainly concentrated in the coastal areas of Zhejiang Province,and lower values were concentrated in Jiangxi and the north of Fujian ***2 observed in Fujian and parts of Jiangxi increased by less than 1.0 ppm during 2014–15,but enhanced significantly by more than 5.0 ppm during 2015–16,perhaps influenced by local emissions and global *** calculated year-to-year CO2 enhancements in the Yangtze River Delta region during 2014–17 that were relatively low and stable,due to the region’s carbon emissions control and reduction *** annual and seasonal amplitudes of CO2 retrieved from AIRS were lower than those from GOSAT in East China,probably owing to the CO2 retrieved from AIRS better reflecting the characteristics of the mid-troposphere,while GOSAT is more representative of near-surface *** spatial and temporal distribution characteristics of CO2 retrieved from OCO-2 were close to those from GOSAT in East China.

关键词： CO2 East China GOSAT AIRS OCO-2

Effect of temper rolling on the bake-hardening behavior of low carbon steel

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International Journal of Minerals,Metallurgy and Materials 2015年第1期22卷 32-36页

作者： Chun-fu Kuang Shen-gen zhang Jun Li Jian Wang Pei Li School of Materials Science and Engineering University of Science and Technology Beijing Research Institute Baoshan Iron and Steel Co.Ltd. School of Materials Science and Engineering Shanghai Jiao Tong University

In a typical process, low carbon steel was annealed at two different temperatures （660℃ and 750℃）, and then was temper rolled to improve the mechanical properties. Pre-straining and baking treatments were subsequently carried out to measure the bake-hardening （BH） values. The influences of annealing temperature and temper rolling on the BH behavior of the steel were investigated. The results indicated that the microstructure evolution during temper rolling was related to carbon atoms and dislocations. After an apparent increase, the BH value of the steel significantly decreased when the temper rolling reduction was increased from 0%to 5%. This was attributed to the increase in solute carbon concentration and dislocation density. The maximum BH values of the steel annealed at 660℃ and 750℃ were 80 MPa and 89 MPa at the reductions of 3%and 4%, respectively. Moreover, increasing the annealing temperature from 660 to 750℃ resulted in an ob-vious increase in the BH value due to carbide dissolution.

关键词： low carbon steel hardening rolling microstructure

Preparation of BaPbO_3 functional ceramics from leaded waste

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Rare Metals 2014年第5期33卷 598-603页

作者： Bin Li Shen-gen zhang Kun zhang De-An Pan Jian-Jun Tian Hu Liu Alex A.Volinsky Institute for Advanced Materials and Technology School of Materials Science and Engineering University of Science and Technology Beijing Beijing Nonferrous Metals and Rare Earth Research Institute Department of Mechanical Engineering University of South Florida

In this study, Pb was separated and used to prepare BaPbO3 conductive ceramics from leaded *** experimental results show that BaPbO3 powder synthesized at 700 °C has particle size of 2–5 lm. The powders were densified by sintering at 1,000 °C for 2 h in the *** BaPbO3 ceramics have high Curie temperature and high-temperature positive temperature coefficient（PTC） resistivity characteristics. Electrical resistivity of BaPbO3 compact increases from 5 × 10^-6Ω·m at room temperature to 4 × 10^-4Ω·m at 750 °C. Compared with the one prepared by pure chemical reagents, the BaPbO3 prepared from leaded waste has the similar characteristics of high Curie temperature and PTC resistivity.

关键词： BaPbO3 Leaded waste Positive temperature coefficient(PTC)

Synergistic effect of cobalt and niobium in Co_(3)-Nb-O_(x)on performance of selective catalytic reduction of NO with NH_(3)

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Rare Metals 2022年第1期41卷 166-178页

作者： Bo-Lin zhang Li-Feng Deng Bo Liu Chun-Yun Luo Michael Liebau Shen-gen zhang Roger Glaser Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China Shunde Graduate School University of Science and Technology BeijingFoshan 528399China Jiangsu Longkingcotech Co. Ltd.Yancheng 224000China Institute of Chemical Technology Universita¨t LeipzigLeipzig 04103Germany e-mail:roger.glaeser

Combining the redox properties of Co and the acid properties of Nb in a Co_(3)-Nb-O_(x)catalyst is shown to provide superior performance in the selective catalytic reduction of NO with NH_(3)(NH_(3)-SCR).Co_(3)O_(4)shows average activity,however,it exhibits a poor N_(2)***_(2)O_(5)is not active for NH_(3)-***,the mixed Co_(3)-Nb-O_(x) catalyst shows higher NO conversion and N_(2)selectivity than the single Co_(3)O_(4)and Nb_(2)O_(5)catalysts at 100–300℃.The results of temperature programmed reduction by H_(2)and X-ray photoelectron(XP)spectra indicate that the addition of Nb changes the chemical states of Co and decreases the concentration of Co^(3+) and Oa,adjusting the activity for catalytic oxidation to a moderate *** suppresses the formation of undesired N_(2)O from the over-oxidation of NH_(3).Incorporation of Co and Nb into one solid synergistically couples their redox behavior and surface acidity,ensuring the high catalytic activity and N2 selectivity in NH3-SCR.

关键词： Co-Nb Selective catalytic reduction Lowtemperature Acid property Redox behavior

Doublely-doped Mg-Al-Ce-V_(2)O_(7)^(4-)LDH composite film on magnesium alloy AZ31 for anticorrosion

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Journal of Materials Science & Technology 2021年第5期64卷 66-72页

作者： Liang Wu Xingxing Ding Zhicheng Zheng Aitao Tang gen zhang Andrej Atrens Fusheng Pan College of Materials Science and Engineering Chongqing UniversityChongqing400044China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing400044China School of Mechanical and Mining Engineering The University of QueenslandBrisbaneQld4072Australia

A doublely-doped layered double hydroxide(LDH)film was produced on an anodized magnesium alloy *** Ce-doped Mg-Al LDH film was prepared by in-situ hydrothermal treatment method,and the intercalation of vanadate was realized by ion-exchange *** structure,morphology and composition of as-prepared LDH film were investigated by X-ray diffractometer,field-emission scanning electronic microscope and energy dispersive *** indicated that a uniform and compact LDH film was formed and the intercalation of Ce^(3+)and vanadate would change the crystal structure of *** results of the potentiodynamic polarization,electrochemical impedance spectra,hydrogen evolution and corrosion weight loss tests showed the Ce^(3+)and vanadate anions significantly improve the impedance of LDH film,and the active double-doped LDH film could effectively protect the magnesium substrate from corrosion.

关键词： Magnesium alloy Doublely-doped LDH film Vanadate Cerium Anticorrosion

New technology for recycling materials from oily cold rolling mill sludge

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International Journal of Minerals,Metallurgy and Materials 2013年第12期20卷 1141-1147页

作者： Bo Liu Shen-gen zhang Jian-jun Tian De-an Pan Ling Meng Yang Liu Institute for Advanced Materials and Technology University of Science and Technology Beijing

Oily cold rolling mill （CRM） sludge is one of metallurgical industry solid wastes. The recycle of these wastes can not only protect the environment but also permit their reutilization. In this research, a new process of ＂hydrometallurgical treatment ＋ hydrothermal synthesis＂ was investigated for the combined recovery of iron and organic materials from oily CRM sludge. Hydrometallurgical treatment, mainly including acid leaching, centrifugal separation, neutralization reaction, oxidizing, and preparation of hydrothermal reaction precursor, was first utilized for processing the sludge. Then, micaceous iron oxide （MIO） pigment powders were prepared through hydrothermal reaction of the obtained precursor in alkaline media. The separated organic materials can be used for fuel or chemical feedstock. The quality of the prepared MIO pigments is in accordance with the standards of MIO pigments for paints （ISO 10601-2007）. This clean, effective, and economical technology offers a new way to recycle oily CRM sludge.

关键词： cold rolling mills sludge disposal hydrometallurgy hydrothermal synthesis recycling, waste utilization