魏洁董俊华柯伟
金属学报
doi:10.3724/SP.J.1037.2011.00474
本文对化学剂冷却热轧螺纹钢在两段式冷却(前段化学剂FM冷却+后段水冷)过程中的温度场进行了有限元模拟, 并在实验室对前段化学剂FM冷却生成的氧化皮的耐蚀性能进行了评价. 采用工业现场一段式水冷的工艺参数, 模拟了一段式水冷的温度场. 对比一段式水冷的温度场, 分析了两段式冷却的工艺参数对冷却过程温度场的影响. 结果表明, 在前段化学剂FM冷却时, 采用较小的对流换热系数, 有利于提高前段化学剂冷却时的氧化温度, 从而改善氧化皮的质量; 在后段水冷时, 在保持原一段水冷的对流换热系数的情况下, 两段式冷却水冷段的冷却曲线与一段式水冷非常接近, 能够满足III级热轧螺纹钢的力学性能的要求. 采用有限元模拟优化的工艺参数, 在实验室模拟了前段化学剂FM冷却过程, 获得了致密的氧化皮, 其耐蚀性能显著优于水冷钢筋, 说明采用前段化学剂冷却来改善水冷钢筋的耐蚀性能是可行的.
关键词:
螺纹钢\化学剂冷却
,
chemical reagent cooling
,
temperature field
,
finite element
,
corrosion resistance
封小松
,
陈彦宾
,
李俐群
金属学报
以镀锌钢板为母材, 以CuSi3焊丝为钎料, 进行了单、双光束激光钎焊实验. 在分析单、双光束激光填丝钎焊传热行为的基础上, 采用有限元方法对激光钎焊温度场进行了数值模拟, 提出了激光填丝钎焊热源模型. 采用体热源来模拟熔化钎料铺展流动引起的传热, 模型考虑了热物性参数随温度的变化带来的非线性影响以及潜热、辐射和对流对传热的影响. 对典型激光钎焊工艺参数下的温度场进行计算, 结果表明: 单光束激光钎焊有较高的温度梯度, 而2 mm焦点间距的双光束钎焊接头峰值温度和温度梯度低,高温区域宽, 更适合于获得良好的钎焊接头.
关键词:
激光钎焊
,
dual laser beam
,
temperature field
,
numerical simulation
曾令可
,
张功元
材料研究学报
应用三维高斯数值积分理论,研制了连续升温温度场的三维有限元计算程序和单元自动划分程序根据面砖坯体和电瓷坯体的厚度特性,采用第一类边界条件,考虑到生坯升温过程中的反应热效应,计算了不同条件下坯内温度场随表面温度的变化情况,并以坯体内外最大温差为标识,整理了计算的温度场证明所设计的程序的正确性,其结果为热应力场的计算提供了可靠的数据
关键词:
陶瓷坯体
,
course of firing
,
temperature field
,
three dimensional FEM
C. Jiang
,
Y.B. Chen
,
B.S. Wu
,
Q.L. Jin
金属学报(英文版)
Temperature field numerical simulation about he heat treatment process curve of large turbine rotor is presented. With simulation software Deform3D in according to the heat treatment processing of China First Heavy Machinery, the details of temperature change at the different location of the rotor is to be found. Once knowing the temperature field change, the duplex grain defect long time existed in large forgings can be solved with a quantitative analysis instead of only the qualitative one. Precondition for small metal samples is brought to simulate microstructure and grain size change of large rotor according to the numerical simulation result. Also, consistent feature with real manufacture is showed from the physical experiment, so that the simulation can be used to not only improve the products process but also prevent wasting unnecessary energy and shorten process periods. The rotor quality is controlled thoroughly with plenty of experiments data.
关键词:
temperature field
,
null
,
null
L. W Zhang
,
R.S. Wang
,
J. Th.M.De Hosson
,
Y.L. Xia and F. G. Wang 1) The State Key Lab. for Materials Modification by Laser
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Ion and Electron Beams
,
Dalian University of Technology
,
Dalian 116023
,
China 2) Department of Applied Physics
,
University of Groningen
,
The Netherlands
金属学报(英文版)
A three-dimensional transient heat transfer model for laser transformation hardening process has been developed in this paper. The finite size of the laser treated sample, the surface heat loss of the sample, the latent heat of phase transformation and the temperature dependence of thermal properties of materials were considered. The heat source was considered as a moving Gaussian heat flux with a constant velocity. Three-dimension unequally spatial grid explicit finite difference equations, alternating direction implicit finite difference equations and implicit finite difference equations were deduced respectively. Three programs to calculate the temperature field were developed using Fortran language. The transient temperature fields of C22, 42CrMo, C60 steel samples during laser transformation hardening process were calculated using these programs, and the widths and depths of laser transformation hardening zones were also predicted. C22, 42CrMo, C60 steel samples were treated by CO_2 laser,the widths and depths of laser transformation hardening zones of these samples were also measured experimentally. The calculated widths and depths of laser transformation hardening zones are in good agreement with the experimental results.
关键词:
temperature field
,
null
,
null
S. X. Wang
,
D. S. Zheng and Y. L. Liu 1) Department of Material Engineering
,
Luoyang Institute of Technology
,
Luoyang 471039
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China 2) Luoyang Copper (Group) Co.
,
Ltd
,
Luoyang
,
China
金属学报(英文版)
The model established in this paper for calculating the unsteady temperature field, in which physical parameters varies with temperatures, is simplified as compared with the classical one by defining the heat conductivity as function of temperature and dealing with the latent heat of phase transformation and boundary conditions. The results show that the probability of absolute error less 2℃ between the calculated and measured values in temperature field calculation reaches above 80%.
关键词:
temperature field
,
null
,
null
HE Youduo
,
Baotou Institute of Iron and Steel Technology
,
Baotou
,
ChinaY.SAHAI
,
The Ohio State University
,
USA
金属学报(英文版)
A mathematical model to represent the fluid flow, temperature distribution and mass transfer in CVD reactors has been developed. The model is used to predict the velocity, temperature, and molar concentration profiles in the tapered annulus of a reactor for silicon deposition from SiCl_4 in H_2. Results of the investigation contribute to the understanding of the transport pro- cesses involved in such a system. The model can also be used for optimizing the design parameters, such as inlet flow rate, susceptor tilt angle, etc.
关键词:
reactor of chemical vapor deposition
,
null
,
null
,
null
