H.W.Liu 1)
,
H.Ding 2) and J.Z.Cui 2) 1) School of Mechanical Engineering
,
Shenyang University
,
Shenyang 110044
,
China 2) School of Materials & Metallurgy
,
Northeastern University
,
Shenyang 110006
,
China
金属学报(英文版)
Porthole dies are important tools in extrusion process to produce hollow sections and the life of the dies counts for the cost of products. In this work, the finite element method was adopted to analyze a particular porthole die to produce hollow rectangle sections which are widely used in construction. The upper die was mainly studied. Because it is symmetrical, a quarter of the die was analyzed. The upper die was divided into 2199 elements with 3018 nodes. Elements were produced by four steps and the geometric shape of the die could be well simulated. The boundary condition was given according to the shape of the welding chamber and an empirical average extrusion stress was adopted, which was 210N/mm 2. Three-dimensional equivalent stresses were received. The original porthole die studied had obvious stress concentration and the stress distribution was very inhomogeneous, which would heavily affect the die life. A new design was proposed in which the portholes were rearranged and their shape and dimension were changed. According to the finite element analysis, the stress distribution of the improved die was quite homogeneous and the stress concentration was lessened.
关键词:
section extrusion
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null
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null
D.Wen 1)
,
Q.K.Cai 2)
,
C.S. Liu 1)
,
Y.J. Guo 1) and Y.H.Zhao 1) 1) School of Materials and Metallurgy
,
Northeastern University
,
Shenyang 110006
,
China 2) Shenyang University
,
Shenyang 110044
,
China
金属学报(英文版)
Laser surface alloying of γ TiAl alloy with nitrogen was studied under the constant protective nitrogen current (20l /min). The experimental results shown that the surface multi layers formed with experimental parameters could be up to 600μm depth; it consists of TiN,Ti 2AlN,α 2 and γ phases, without AlN, and the irregular coarse continuous “flow” line,dendrite,needle and granular nitrides disperse on the fine dendrite casting α 2 and γ phases substrate. The microstructure and compositions in the nitiding layer were determined and analyzed by SEM and EPMA and the mechanism for the formation of microstructure in the nitriding layer was also discussed.
关键词:
laser surface alloying
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null
,
null
H.W.Liu 1)
,
H.Ding 2) and J.Z.Cui 2) 1) School of Mechanical Engineering
,
Shenyang University
,
Shenyang 110044
,
China 2) School of Materials & Metallurgy
,
Northeastern University
,
Shenyang 110006
,
China
金属学报(英文版)
The samples obtained by Finite Element Method (FEM) simulation for section extrusion process have been trained on BP Neural Networks. The mapping relationsbetween die's geometrical parameters and energetic parameters, such as stress and strain generated in the die are established. The extrusion process model and its expert system are also determined. The excellent expansibility this system possesses provides a new prospect for the future development of expert system for section extrusion dies.
关键词:
BP neural networks
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null
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null
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null
Y.M.Wang and L.X.Ding Department of material
,
School of Mechanical Engineering
,
Shenyang University
,
Shenyang 110044
,
China
金属学报(英文版)
The research is carried out through specification measurement of magnetic property, photo analysis of electronic microscope, metallographic analysis, micro hard and so on means. The initial researches have been done about the influence on material property by solid solution treatment, heat magnetic treatment and aging treatment technology of the low cobalt Fe Cr Co alloy. Therefore, better productive technologies have been found.
关键词:
permanent magnetic alloy
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null
,
null
,
null
P.Y.Zong and L.R.Zhang Mechanical Engineering College
,
Shenyang University
,
Shenyang 110044
,
China
金属学报(英文版)
The Authors of this Article have done research on the cracking resistance of cold welding surfacing electrodes for blast furnace valves by adjusting the basicity of slag component, decreasing the hydrogen content and improving microstructure. The DF 2 Cold Welding Surfacing Electrodes prove to possess the following characters: 1) Excellent cracking resistance for surfacing alloys at normal temperature. 2) Excellent cracking resistance for repair welding and rewelding. 3) Excellent machinability for surfacing alloying.
关键词:
cold welding
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null
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null
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null
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null
L.X.Ding and Y.M.Wang Department of material
,
School of Mechanical Engineering
,
Shenyang University
,
Shenyang 110044
,
China
金属学报(英文版)
The article uses the method of regression statistics to obtain the regression formula of iron fluid nodule ratio Q and compacted graphite ratio R, through rare earth magnesium treatment. At the same time it has given thejudging figure of Q and R, considering oxygen activity and temperature. When using oxygen activity to judgenodule ratio and compacted graphite ratio of the ironfluid treated by rare earth magnesium alloy, its limit value changes with the change of temperature.
关键词:
nodule ratio
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null
,
null
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null
