WANG Minting
,
ZANG Xinliang
,
LI Xuetong
,
DU Fengshan
钢铁研究学报(英文版)
Using the nonlinear rigidviscoplastic finite element method (FEM), a finite element simulation of the hot strip continuous rolling process was done, which completely integrates different phenomena such as the metallurgical behavior of the strip and the thermomechanics in the strip based on the physical metallurgical microstructural evolution law. By combining with the process parameters of certain 2 050 mm hot strip rolling, an actual rolling process of low carbon steel SS400 was simulated using the FEM model. Based on the simulation results, the distributions of the strain field, the temperature field, and the microstructure were presented. Meanwhile, the simulated rolling force, temperature, and microstructure are in good agreement with the measured results.
关键词:
hot rolling;FEM;microstructure;coupling
WANG Minting
,
LI Xuetong
,
DU Fengshan
钢铁研究学报(英文版)
A simulation model for tworoll cross wedge rolling (CWR) was presented by using threedimensional rigidplastic finite element method (FEM). The whole forming process of CWR, including knifing zone, guiding zone, stretching zone, and sizing zone, was simulated using the model in which dynamic adaptive remeshing technology for tetrahedral solid elements was used to fix element distortion. Based on the simulation results, the distributions of metal flow field, strain field, and damage field, and the geometry of the workpiece′s end were analyzed. These results could provide theoretical guidance for realizing net shaping and reasonable design of tools.
关键词:
cross wedge rolling;finite element method;plastic forming;simulation
LI Xuetong
,
WANG Minting
,
DU Fengshan
钢铁研究学报(英文版)
Using threedimensional rigidviscoplastic finite element method (FEM), a coupling multivariable numerical simulation model for steel plate rolling has been established based on the physical metallurgy microstructural evolution rule and experiential equations. The effects of reduction, deformation temperature, and rolling speed on the deformation parameters and microstructure in plate rolling were investigated using the model. After a typical rolling process of steel plate 16Mn is simulated, the strain, temperature, and microstructure distributions are presented, as well as the ferrite grain transformation during the period of cooling. By comparing the calculated ferrite grain sizes with measured ones, the model is validated.
关键词:
hot rolling;plate;FEM;microstructure;coupling
Q.S. Liu1
,
2
,
3)
,
L.C. Zhao3)
,
G.X. Dong2) and N.J. Gu1) 1) Heibei University of Technology
,
Tianjin 300130
,
China 2) Tianjin Institute of Technology
,
Tianjin 300191
,
China 3) Harbin University of Technology
,
Harbin 150001
,
China
金属学报(英文版)
Theconstruction changinginthereversetransformation ofthestress induced εMin Fe 17 Mn 10 Cr 5 Si 4 Ni alloy is carefully inspected in transmission electron microscope, and then stress induced εM procedure of reverse transformation is analyzed. The behavior of reverse transformationisdissimilar when the organization of εMis different. The reversetransfor mation ofεM withtheshapeofsingle plateandstripisrelativelyeasy,anditsreversibilityincrystallographiciseasilytocarryout,fortheεM with multilayerstructure,thereversetrans formationtakes placein isolatedlayers, fortheεMthat grows well,thereversetransforma tion isrelatively difficult becauseofthe ductile harmonization between itsinternalorganiza tion structures.
关键词:
stress induced εM
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null
,
null
徐佩
,
卢旭鑫
,
汪传斌
,
杨善中
,
孙晓红
,
丁运生
高分子材料科学与工程
为改善多壁碳纳米管(MWNT)在低密度聚乙烯(LDPE)中的分散性及复合材料的界面特性,采用溴化-1-十六烷基-3-甲基咪唑基离子液体([C16min]Br)对MWNT进行表面改性,并用Raman光谱对改性效果进行了表征.将经过修饰的碳纳米管(MIL)与LDPE熔融共混得到MIL/LDPE复合材料,采用场发射扫描电子显微镜(FESEM)和阻抗分析仪(LCR)对复合材料的结构与介电性能进行了分析.结果表明,相比与MWNT/LDPE(渗流阈值为5.2％,介电常数为82,介电损耗为0.93),MIL/LDPE(渗流阈值为9.1％,介电常数为169,介电损耗为0.51)介电常数增大,介电损耗降低.并且在低温时,MIL/LDPE介电常数随温度的变化甚小,显示出良好的温度-介电常数特性.
关键词:
咪唑基离子液体
,
碳纳米管
,
低密度聚乙烯
,
介电性能
Journal of Materials Research
The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.
关键词:
room-temperature
Surface & Coatings Technology
A duplex lower temperature chromizing treatment at 600 degrees C for 120 min followed by 860 degrees C for 90 min was performed on a low carbon steel plate with a nanostructured surface layer, induced by surface mechanical attrition treatment (SMAT) [Z.B. Wang, J. Lu, K. Lu, Acta Mater. 53 (2005) 2081]. Microhardness, wear and corrosion resistances of the chromized SMAT sample were measured, in comparison with those of the chromized coarse-grained counterpart and the as-annealed coarse-grained sample. Experimental results showed that these properties were improved markedly. The much enhanced properties of the chromized SMAT sample relative to the chromized coarse-grained counterpart might originate from its superior microstructures, i.e., a much thicker chromized surface layer with smaller grains and more homogenous phase-distribution, due to the employed processes of the SMAT and the duplex lower temperature chromizing treatment. (c) 2006 Elsevier B.V. All rights reserved.
关键词:
low carbon steel;surface mechanical attrition treatment;lower;temperature chromizing;wear resistance;corrosion resistance;mechanical attrition treatment;surface nanocrystallization;alloy;resistance;diffusion;iron
LIN Jialiu ZHU Shigen YU Zhenzong Tsinghua University
,
Beijing
,
China
金属学报(英文版)
The stress-strain relation for cast low alloy carbon steel at solidification temperature has been examined by the authors' own desingned apparatus for rheological properties measurement.The rheology model,the stress-strain constitutive equation and the rheological parameters therefrom of the cast steel were proposed.Thus the theoretical basis and calcula- ting data for computerized s#nulation on the stress-strain relation and thermal cracking of the cast steel were suggested.
关键词:
rheological behaviour
,
null
,
null
,
null
,
null
