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Microstructure and Fracture Morphology in the Welding Zone of T91 Heat-resisting Steel Used in Power Station

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Journal of Materials Science & technol.gy 2002年第5期18卷 427-430页

作者： YajiangLI BingZHOU TaoFENG JiangweiREN harbin Inst. of technol. Harbin 150001 China Shandong univ. Ji'nan 250061 China

Microstructure performance in the welding zone of T91 heat-resistant steel under the condition of TIG welding was researched by means of metallography, X-ray diffraction and scanning electron microscope (SEM). Experimental results indicated that microstructure of T91 weld metal was austenite + a little amount of S ferrite when using TGS-9cb filler wire. Substructure inside the austenite grain was crypto-crystal lath martensite, on which some Cr23C6 blocky carbides were distributed. The maximum hardness (HRC44) in the welding zone is near the fusion zone. There existed no obvious softening zone in the heat-affected zone (HAZ). For T91 steel tube of $63 mmx5 mm, when increasing welding heat input (E) from 4.8 kJ/cm to 12 5 kJ/cm, fracture morphology in the fusion zone and the HAZ changed from dimple fracture into quasi-cleavage fracture (QC). Controlling the welding heat input of about 9.8 kJ/cm is suitable in the welding of T91 heat-resistant steel.

关键词： T91 heat-resistant steel. Welding. Microsrructure

Numerical Simulation of Welding Deformation for Hull Superstructure Steel Based on the Finite Element Analysis

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Journal of Materials Science & technol.gy 2003年第Z1期19卷 212-214页

作者： Liu, Liming Liang, Guoli Liu, Yujun Zhan, Zheng Dalian univ. of technol. Dalian 116024 China Dalian Dockyard Dalian 116020 China Lab. of Adv. Welding technol. Harbin Inst. of Technol. Harbin 150001 China

Using finite analysis element software, the transient displacement field of automatic submerged arc welding is established. It was also considered that the thermal physical properties changes were depended on the temperatureand the heat loss on the surface. At the same time, it analyzed the influence of the deformation and stress, whichgenerated in the plate butt-welding process, to the superstructure steel welding deformation. The result showedthat the deformation and stress generated in the steel plate butt-welding process are considered to be the mainfactors to influence the welding deformation of superstructure steel. It found the effective ways to reduce the weldingdeformation of the hull superstructure steel is to relieve the butt-welding deformation and release butt-welding stressbefore welding the hull superstructure steel.

关键词： Hull superstructure steel, Finite element analysis, Welding deformation

Distribution of Inherent Strains and Residual Stressesin Medium Thickness Plate Weldment

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维普期刊数据库

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Journal of Materials Science & technol.gy 2001年第2期17卷 252-256页

作者： Peng HE and Jiuhai ZHANG National Key Laboratory of Advanced Welding Production technol.gy, HIT, harbin 150001, China Toshio Terasaki and Testuya Akiyama Department of Materials Science and Engineering, Kyushu Institute of technol.gy, Japan harbin Inst. of technol. Harbin 150001 China

A fundamental theory for the analysis of residual welding stresses and deformation based on the inherent strain distribution along the welded joint is introduced. Distribution of inherent strains and longitudinal residual stresses in medium thickness plate weldment is calculated and analyzed. A new method of calculating inherent strains and longitudinal residual stresses is proposed.

关键词： In Distribution of Inherent Strains and Residual Stressesin Medium Thickness Plate Weldment Ta

Microstructure and strength of TiAl/40Cr joint diffusion bonded with vanadium-copper filler metal

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中国有色金属学会会刊：英文版 2002年第5期12卷 811-813页

作者：何鹏冯吉才钱乙余张炳刚 harbin Inst. of technol. Harbin 150001 China

Intermetallics TiAl was diffusion-bonded to steel 40Cr in vacuum furnace with interlayer V/Cu. The results show that infinite sosoloid that made for bond performance is formed at the interface of V/Cu and Cu/40Cr, and three acting layers are formed at the interface of TiAl/V including Ti 3Al layer at TiAl side, intermittent V 5Al 8 layer in the middle and Ti-V sosoloid at V side. Fragile reactors V 5Al 8 arising at the interface lead to bad performance of joints, and the strength of the joint is 200 MPa, while it was still higher than the strength of the joint intermetallics TiAl to 40Cr steel diffusion-bonded directly. Intermetallic TiAl and 40Cr steel are diffusion-bonded successfully by using a composite isolation layer V/Cu.

关键词：扩散结构显微结构钛铝合金金属间化合物钒铝焊料 TiAl/40Cr

Modeling and Control of Welding Flexible Manufacturing Cell Using Petri Net

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Journal of Materials Science & technol.gy 2001年第1期17卷 185-186页

作者： Tao QIU Shanben CHEN Yuntao WANG and Lin WU National Key Laboratory of Advanced Welding Production technol.gy, harbin institute of technol.gy, harbin 150001, China harbin Inst. of technol. Harbin 150001 China

A new welding flexible manufacturing cell (WFMC) with intelligent welding sensors was investigated. Based on the analysis of information flow in WFMC, automation Petri net control model has been studied, Which can be... 详细信息

关键词： Petri Net flexible manufacturing system information flow control model Petri net

A New Model of Interfacial Physical Contact in Diffusion Bonding

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Journal of Materials Science & technol.gy 2004年第1期20卷 109-112页

作者： Peng HE, Jicai FENG and Yiyu QIANNational Key Laboratory of Advanced Welding Production technol.gy, harbin Institute of technol.gy, harbin 150001, China Lab. of Adv. Welding technol. Harbin Inst. of Technol. Harbin 150001 China

Through eliminating voids not affecting the primary bonding process, and incorporating interlayer and flexible base material, the interface geometry character and brief mathematics process were put forth. Through analyzing contact process of diffusion bonding, contact area model was settled. It can interpret the phenomenon of different interface areas taking on different strengths. In the course of physical contact, shear stresses serve an important function for the plastic deformation and the cohesion of interface voids.

关键词： Diffusion bonding Physical contact Interface layer

Current Density Distribution in Double-Sided GTAW Process

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Journal of Materials Science & technol.gy 2001年第1期17卷 187-188页

作者： Hongming GAO Lin WU and Honggang DONG National Key Laboratory of Advanced Welding Production technol.gy, harbin institute of technol.gy, harbin 150001, China harbin Inst. of technol. Harbin 150001 China

A three dimensional current density distribution in double-sided gas tungsten arc welding (GTAW) proces is performed. The current density distribution field is evaluated by numerically solving Maxwell equations in the domain of the workpiece. In the boundary condition, the current density on. the workpiece surface is assumed as Gaussian distribution. Results show that the current distribution in DSAW is different from single side arc welding, it is more concentrated and the relative location of the two torches influence the current distribution greatly.

关键词： current density distribution current distribution gas tungsten arc welding Gaussian distribution boundary condition workpiece surface three dimensional Maxwell equations

Superplasticity in an Aluminum Alloy 6061/Al_2O_3p Composite

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Journal of Materials Science & technol.gy 2001年第6期17卷 653-656页

作者： Lihong HAN, Jitai NIU and Darning JIANG The National Key Laboratory of Advanced Welding Production technol.gy, harbin Institute of technol.gy, harbin 150001, China Tsunernichi Imai National Industrial Research harbin Inst. of technol. Harbin 150001 China

The superplasticity of an Al203p/6061Al composite, fabricated by powder metallurgy techniques, has been investigated. Instead of any special thermomechanical processing or hot rolling, simple hot extrusion has been employed to obtain a fine grained structure before superplastic testing. Superplastic tensile tests were performed at strain rates ranging from 10-2 to 10-4 s-1 and at temperatures from 833 to 893 K. A maximum elongation of 200% was achieved at a temperature of 853 K and an initial strain rate of 1.67×103 s-1. The highest value obtained for the strain rate sensitivity index (in) was 0.32. Differential scanning calorimeter was used to ascertain the possibility of any partial melting in the vicinity of optimum superplastic temperature. These results suggested that no liquid phase existed where maximum elongation was achieved and deformation took place entirely in the solid state.

关键词： Al Superplasticity in an Aluminum Alloy 6061/Al2O3p Composite rate high DSC Figure

Synthesis of La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(3-δ) Powder for Solid Oxide Fuel Cell by a Nitrate-Citrate Combustion Route

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Journal of Materials Science & technol.gy 2004年第6期20卷 791-793页

作者： Naiqing ZHANG, Kening SUN, Derui ZHOU and Ningning WUharbin Institute of technol.gy, harbin 150001, China harbin Inst. of technol. Harbin 150001 China

A nitrate-citrate combustion route to synthesize La0.9Sr0.1Ga0.8Mg0.2O3-σ powder for solid oxide fuel cell application was presented. This route is based on the gelling of nitrate solutions by the addition of citric acid and ammonium hydroxide, followed by an intense combustion process due to an exothermic redox reaction between nitrate and citrate ions. The optimum technical parameters are that the pH value is 5, and the molar ratio of citric acid to the total metallic ion is 1.5:1. X-ray diffraction characterization of calcined gel shows that pure phase was synthesized after calcination at 1400℃for 10 h, and the TEM result shovvs the calcined powder with average particle size is about 150 nm. The grain resistance contributes to the total resistance of sintered peliet below 500℃. The conductivity of the sintered peliet at 800℃ was 0.07 S-1·cm-1 higher than the conductivity of YSZ (0.05 S-1·cm-1 at 800℃)

关键词： La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(3-δ)powder Gel-combustion synthesis Solid oxide fuel cell