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Revision of a CCT Diagram of the Simulated ADI Weld Metal and Its Application in Actual Welding

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Journal of Materials Science & Technology 1998年第2期14卷 147-150页

作者： Li, Deyuan Zhou, Zhenfeng sun, daqian Shao, Chengji Jilin Univ Technol Changchun 130025 Peoples R China Shenyang Polytech Univ Shenyang 110023 Peoples R China

A continuous cooling transformation (CCT) diagram of the simulated austempered ductile iron (ADI) weld metal has been developed by means of the Formastor-F diagram measurement apparatus, and revised by comparing with the actual welding. Finally, the revised diagram was used to determine the welding technology. (Edited author abstract) 4 Refs.

关键词： Iron alloys

Microstructures and Properties of NiCrBSi/WC Biomimetic Coatings Prepared by Plasma Spray Welding

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Journal of Bionic Engineering 2015年第4期12卷 592-603页

作者： Shiming Huang daqian sun Desheng Xu Wenquan Wang Hongyong Xu Key Laboratory of Automobile Materials of Ministry of Education School of Materials Science and Engineering Jilin University Changchun 130022 China

The NiCrBSi/WC biomimetic coatings were prepared on the low carbon steel substrate by plasma spray welding with mixed powders （WC-Col2＋NiCrBSi） based on the bionic principles, and the coating characteristics were investigated. The results indicate that the coatings have a full metallurgical bond in coating/substrate interface, and consist mainly ofy-Ni, WC, Cr23C6, Cr7C3, Ni3Si, CrsB3, and FeNi3 phases. The powder composition influences the microstructures and properties of the coatings. The WC content and the hardness of coatings increase with the mass fraction of WC-Co 12 powder. The biomimetic coatings have much higher wear resistance compared with the low carbon steel, which is attributed to the combination of hard WC and chromium carbide particles （bionic units） and soft y-Ni matrix in the coatings. It is favorable to prepare the biomimetic coating by plasma spray welding with the mixed powders （20wt%WC-Col2＋80wt%NiCrBSi） for improving the wear resis- tance of the coating.

关键词： plasma spray welding biomimetic coatings mixed powders microstructures properties

Low temperature spark plasma sintering of TC4/HA composites

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Progress in Natural Science:Materials International 2016年第2期26卷 192-196页

作者： Huiliang Shao Lei Cao daqian sun Zhankui Zhao College of Materials Science and Engineering Jilin University Key Laboratory of Advanced Structural Materials Ministry of Education College of Materials Science and Engineering Changchun University of Technology

Ti6Al4V/hydroxyapatite composites(TC4/HA) have been prepared by high energy ball milling and low temperature spark plasma sintering at 600 °C, 550 °C, 500 °C and 450 °C, respectively. The sintering temperature of the composites was sharply decreased as the result of the activation and sur fi cial modi fi cation effects induced from high energy ball milling. The decomposition and reaction of hydroxyapatite was successfully avoided, which offers the composites superior biocompatibility. The hydroxyapatite in the composites was distributed in gap uniformly, and formed an ideal network structure. The lowest hardness, compressive strength and Young’s modulus of the composites satisfy the requirements of human bone.

关键词： High energy ball milling Composite Mechanical properties

Microstructural Features of Friction-Welded Ti-6Al-4V Joint

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Journal of Materials Science & Technology 2000年第1期16卷 59-62页

作者： daqian sun Zhenan REN Zhenfeng ZHOU T.North Yang ZHAI S.Sathian Jilin University of Technology Changchun 130025China University of Toronto Toronto M5S 3E4Canada

Microstructural features of friction-welded Ti-6Al-4V joint have been investigated by both optical microscope and transmission electron microscope (TEM). The microstructure of the welded joint is not uniform. It can be classified into the phase transformed region(P), the deformed region(D) and the region of unchanged base metal(B). In the phase transformed region, the microstructure consists of platelike, acicular and equiaxed alpha phase plus beta phase between them and the dislocations can be observed in some or phase particles. The equiaxed alpha phase mainly distributes in the near center of rod specimen. The quantity of platelike and acicular alpha phase and the size of the grains increase progressively along the radial direction of the rod type welded joint. In the deformed region, the grains are reoriented and the microstructure consists of the elongated alpha phase containing a lot of dislocations and intergranular beta phase.

关键词： Titanium alloys

New advances for cast iron welding in China in last decade

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China Welding 1995年第2期4卷 81-88页

作者： sun daqian Ren Zhenan and Zhou Zhenfeng(Jilin University of Technology. Changchun)

In this paper. the research activities in the field cast iron welding in China in China in last decade are introduced. Investigations related to hot cracking and cold cracking of cast iron welding are reviewed Develop... 详细信息

关键词： advances. cast iron. cracking. welding. Consumables

Study on microstructures and properties of preheated flash butt welded SW400 steel joints

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China Welding 2018年第3期27卷 42-52页

作者： Gong Tinghe Gong Mingyue sun daqian CRRC Changchun Railway Vehicles Co. Ltd.Changchun 130062China School of Materials Science and Engineering Jilin UniversityChangchun 130025China

Under the spirit of sustainable development, ‘lightweight’ has been gradually included into the vehicle design criterion by many manufacturers and used in automobile production. Following this trend, domestic wheel suppliers also begin to study the technology of lightweight wheel. One way to achieve this goal is improving strength grade of the steel and optimizing the structure design in the field of steel wheels. But there are a few problems in flash butt welding process in the application of high strength steel, leading to high rejection rates. SW400 steel is a special high strength wheel steel developed by Benxi Steel. Taking SW400 steel as the research material, this article studys the feasibility of improving the properties of rim flash butt welded joints by adding preheating process.

关键词： preheated flash butt welding heat input characteristics of thermal cycle microstructures mechanical properties

Effects of Alloying Elements on Microstructure and Erosion Resistance of Fe-C-Cr Weld Surfacing Layer

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Journal of Materials Science & Technology 2003年第4期19卷 351-354页

作者： daqian sun, Wenquan WANG, Zhaozhi XUAN, Yue XU and Zhenfeng ZHOUSchool of Materials Science and Engineering, Jilin University, Changchun 130025, China Sch. of Mat. Sci. and Eng. Jilin Univ. Changchun 130025 China

Effects of alloying elements on microstructure and erosion resistance of Fe-C-Cr weld surfacing layer have been studied. The experimental results show that increasing C and Cr content favors improving the erosion resistance of the layer, and the excessive C and Cr result in decreasing the erosion resistance at 90 deg. erosion. That Mo, Nb or Ti improves the erosion resistance of Fe-C-Cr weld surfacing layer is mainly attributed to increasing the amount of M7C3 and forming fine NbC or TiC in austenite matrix, but the excessive Mo, Nb or Ti is unfavorable. The addition of Mo, Nb and Ti in proper combination possesses stronger effect on improving the erosion resistance and the erosion resistance (εA) of Fe-C-Cr weld surfacing layer with fine NbC, TiC and M7C3 distributing uniformly in austenite matrix obviously increases to 2.81 at 15 deg. erosion and 2.88 at 90 deg. erosion when the layer composition is 3.05C, 20.58Cr, 1.88Mo, 2.00Nb and 1.05Ti (in wt pct).

关键词： Weld surfacing layer Alloying elements Erosion resistance

Effect of electrode morphology on steel/aluminum alloy joint

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China Welding 2019年第1期28卷 16-27页

作者： Zhang Yueying sun daqian Su Lei Liu Yanjun Key Laboratory of Automobile Materials of Materials Jilin University

Microstructure characteristics of dissimilar-metal resistance spot welded joints of SUS301 L austenitic stainless steel and 6063-T6 aluminum alloy, and effects of electrode morphology were studied. Results indicated that welded joints of dissimilar materials between austenitic stainless steel and aluminum alloy had characteristics of welding-brazing. The aluminum nugget consisted mainly of the cellular crystal, cellular dendrites and dendrites. The interface between austenitic stainless steel and aluminum alloy had a two-layered structures:a flat front surface θ-Fe_2Al_5 on the steel side and a serrated morphology θ-FeAl_3 on the aluminium alloy side, and it was the weakest zone of the joints. The electrode morphology had great effects on spot welded joints of stainless steel and aluminum alloy. The custom electrodes were a planar circular tip electrode with tip diameter of 10 mm on the stainless steel side and a spherical tip electrode with spherical radius of 35 mm on the aluminum alloy side. When the custom electrodes were used, the nugget diameter, tensile shear load and indentation ratio of spot welded joint were 7.22 mm, 3 606 N and 10.71%, respectively. The nugget diameter and joint tensile shear load increased by 34% and 102% respectively, and the indentation ratio decreased by 65% compared with the F-type electrodes(nugget diameter: 5.384 mm, tensile-shear load 1 783 N, indentation rate 30.94%). Therefore, it was more favorable to use the custom electrodes for improving the mechanical properties and appearance quality of resistance spot welded joints of stainless steel and aluminum alloy.

关键词： aluminium alloy stainless steel resistance spot welding microstructures mechanical properties

Effects of nugget alloying on microstructures and properties of resistance spot welded joints of aluminum and steel

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China Welding 2016年第3期25卷 36-41页

作者： Zhang Yueying sun daqian Li Hongmei Gu Xiaoyan Liu Yanjun Key Laboratory of Automobile Materials School of Materials Science and Engineering Jilin University Changchun 130025 SAIC Motor Technology Center Shanghai 201804.

The resistance spot welding of 6063-T6 aluminum alloy and 16Mn steel was studied by nugget alloying. The results indicated that the Al-steel joint had characteristics of welding-brazing. The nugget zone consisted mainly of α-Al solid solution with dislocations and fine Mg2Si particles. The interface zone had a double-layer structure： Fe2Al5 layer at steel side and Fe4Al13 layer at Al nugget side. The nugget alloying has a significant effect on the joint properties by changing phase composition and refinement of grains. When alloy elements Cu, Zn, Ti and Ni were added, the tensile shear load of Al-steel joints reached 2 780 N, 2 910 N, 2 915 N and 2 929 N respectively, which increased by 24. 1%, 29.9%, 30. 1% and 30. 7% respectively compared with that （2 241 N） of joint without nugget alloying. Therefore, it is an effective way for improving mechanical properties of resistance spot welded Al-steel joints.

关键词： 6063-T6 aluminum alloy 16Mn steel resistance spot welding nugget alloying