材料期刊网

OPTIMIZATION OF MATERIAL PROPERTIES THROUGH THE LINKAGE OF SIMULATION CALCULATIONS WITH THE REAL ROLLING PROCESS OF DIFFERENT STEEL GRADES FOR BABS AND WIRE ROD

R. Kohlmann , M. Kruse , M. Meyer and U. Plociennik( 1) Betriebsleiter Qualitatsstelle , Krupp Edelstahl Profile , Siegen 2)Research and Development , SMS Schloemann Siemap AG , Dusseldorf/Germany)

金属学报(英文版)

Material properties were optimized through the linkage of numericalsimulation with the real rolling pro- cess. A few different steel grades for bars and wire rode were taken as the examples.The examples.The commerical FEM code MARC/MENTAT was used for the numerical simulation of the three - dimensional elas- toplastic rolling process coupled with temperature.The simulation calculation for temperation for temperature control in- side the rolling mill was carried out by use of the SMS - developed CCT system (controlled coling technolgy). New rolling - technological precess was developed for bars and wire rods based on the numerical results.Steel 38MnSiVS5 and steel 41Cr4 were taken as the examples. Keywrods: rolling,numerical simulation, material property optimigation

关键词:

Refinement of Fourier coefficients from the Stokes deconvoluted profile

材料科学技术（英文）

Computer-aided experimental technique was used to study the Stokes deconvolution of X-ray diffraction profile. Considerable difference can be found between the Fourier coefficients obtained from the deconvolutions of singlet and doublet experimental profiles. Nevertheless, the resultant physical profiles corresponding to singlet and doublet profiles are identical. An approach is proposed to refine the Fourier coefficients, and the refined Fourier coefficients coincide well with that obtained from the deconvolution of singlet experimental profile.

关键词: X-ray diffraction;Fourier transforms;Fourier coefficients

Flatness and Profile Integration Control Model for Tandem Cold Mills

SHAN Xiu-ying , LIU Hong-min , JIA Chun-yu , SUN Jian-liang

钢铁研究学报(英文版)

Using the effective matrix methods of flatness and profile control synthetically, the flatness and profile integration control scheme for tandem cold mills is built in order to increase flatness and profile control precision of tandem cold mills. Corresponding control strategies are adopted for various control objectives of different stands and the coordination control strategies of various stands are given, which makes the on-line flatness control cooperate with on-line profile control and implements the parallel control of different stands. According to the measured flatness and profile data of some 1550 mm tandem cold mills, the control scheme is verified and the result indicates that the scheme has high flatness and profile control precision with steady and reliable control process. A new way and method is supplied for researching shape control of tandem cold mills.

关键词: flatness , profile , shape , effective matrix , tandem cold mill

Fluidity and Temperature Profile of Ductile Iron in Thin Sections

Marcin Górny

钢铁研究学报(英文版)

It has been shown that it is possible to produce thin wall ductile iron (TWDI) castings of considerable length using an Archimedes spirals with a wall of 1, 2 or 3 mm in thickness. The fluidities for different moulding materials ［(classical mould, chemically bonded silica sand and chemically bonded low-density alumina-silicate ceramic sand (LDASC)］, chemical composition, and pouring temperature were estimated. There is a significant temperature drop in thin sections (contrary to typical sections) during the mould filling. A profile of real temperature drop is presented along with theoretical predictions. The high temperature drop of liquid iron results in an increased cooling rate (before the eutectic equilibrium solidification temperature), which in turn affects the solidification and microstructure of TWDI castings. Microstructures were characterized quantitatively using an image analyser. Structure parameters for different wall thicknesses and moulding materials (graphite nodule count, ferrite and cementite fraction) are plotted, which is versus distance from the entrance to the mould cavity. It has been shown that the thin wall castings have a gradient structure. Moreover, a strong influence of LDASC sand (material with low ability to absorb the heat) on the structure parameters of TWDI castings is presented.

关键词: fluidity , ductile iron , thin wall casting , Archimedes spiral

MATHEMATICAL MODELS OF NITROGEN CONCENTRATION PROFILE OF ION NITRIDED LAYERS AND COMPUTER SIMULATION

XIA Lifang YAN Mufu Harbin Institute of Technology , Harbin , China Laboratory of Metal Materials and Heat treatment , Harbin Institute of Technology , Harbin , China

金属学报(英文版)

The mathematical models of the kinetics of the layer growth at different ion nitriding condi- tions of armco iron.steels 45,40Cr,42CrMo and 38CrMoAl have been established.Based on these models the expression of nitrogen concentration profile of ion nitrided layers have been deduced with profile simulating method.They are C_=C_(min)~+(P_4)/(ξ_1-x)+(P_5)/(ξ_(10)~2)(ξ_1-x)~2 C_(γ′)=C_(min)~(γ′)+(P_1)/(ξ_(21))(ξ_2-x)+(P_2)/(ξ_(21)~2)(ξ_2-x)~2 C_α=C_(min)~α+(C_(33))/(C_(33))/(ξ_(32))(ξ_3-x)~3 Using these models,the kinetics of layer growth and the nitrogen concentration profile of ion nitrided layers were sinulated on Apple-Ⅱ computer.Results show that the simulated curves coincide quite well with the experimental data.

关键词: computer simulation , null , null

Freeze Profile and Heat Balance Calculation of the 160kA Drained Cell

X.P. Li , J. Li , Y.Q. Lai , H.Q. Zhao , Y.X. Liu

金属学报(英文版)

A 2D full cell thermo-electric model of 160kA drained cell was set up using finite element code to calculate its freeze profile, then the drained cell model was modified according to the freeze profile computed and its heat balance was calculated. Compared with that of a 160kA conventional Hall-Heroult cell (H-H cell), though the melts volume of the drained cell reduced greatly, the whole heat loss from it didn't drop down apparently, and an analysis was presented in the paper. On the other hand, the anode- cathode distance (ACD) of a drained cell was much less than that of a H-H cell, so the voltage drop on it and heat produced decreased too, steps should be taken to keep a workable heat balance on a drained cell.

关键词: drained cell , null , null

RELATIONSHIP BETWEEN J-INTEGRAL AND FRACTURE SURFACE AVERAGE PROFILE

Y.G. Cao

金属学报(英文版)

To investigate the causes that led to the formation of cracks in materials, a novel method that only considered the fracture surfaces for determining the fracture toughness parameters of J-integral for plain strain was proposed. The principle of the fracture-surface topography analysis (FRASTA) was used. In FRASTA, the fracture surfaces were scanned by laser microscope and the elevation data was recorded for analysis. The relationship between J-integral and fracture surface average profile for plain strain was deduced. It was also verified that the J-integral determined by the novel method and by the compliance method matches each other well.

关键词: FRASTA , null , null

Research on a New Process: Warm Tension-Rotation Bending of AZ31 Extruded Profile

Advanced Science Letters

The profiles of AZ31 magnesium alloy were deformed by a warm tension-rotation bending process. The effects of forming temperature, bending angle and pre-tension amount on the springback of the profiles were investigated. The microstructures of AZ31 extruded profiles and bent profiles were observed by optical microscopy. Experimental results indicate that the springback angle decreases with decreasing of the bending angle and increasing of the forming temperature and the pre-tension amount. Grain sizes in the bent profile are smaller than those in the extruded one. A lot of twins in the bent profile indicate twinning appear during the bending. Twinning improves the formability of AZ31 extruded profile.

关键词: AZ31 Extruded Profile;Tension-Rotation Bending;Springback;Microstructure;magnesium-alloy;mechanical-properties;extrusion conditions;microstructure;temperature;formability;precision;behavior;sheets

Analysis of the deconvolution of X-ray diffraction profile and simultaneous calculation of Bragg angle

Acta Physica Sinica

To eliminate the influence of experimental error, analytical function is adopted to model the experimental profiles. Much attention has been paid to the analysis of the effects of such factors as K alpha doublet, broadening and alignment of profiles etc, on the Fourier coefficients and deconvoluted profile obtained from the Stokes correction. The reliability of the separation of size(-) and strain(-) broadening from Fourier coefficients or deconvoluted profile is estimated. A method is proposed for the simultaneous refinement of accurate Bragg angle from the deconvolution procedure.

关键词: X-ray diffraction profile;Fourier transforms;physical profile;Bragg;angle

Calculation Method of Optimal Speed Profile for Hot Plate During Controlled Cooling Process

WANG Bingxing , CHEN Xiaolin , TIAN Yong , WANG Zhaodong , WANG Jun , ZHANG Dianhua

钢铁研究学报(英文版)

The healthy and rapid development of the controlled cooling technology was hampered by the uneven cooling phenomenon. During the process of hot plate production, the homogeneous cooling along the length direction of plate was constrained by lots of factors. And because the speed was a flexible control parameter, the calculation method of optimal speed profile was developed based on the measured start cooling temperature and its matrix equation was solved by the Cholesky decomposition method. The optimal speed profile was used in online control system. As a result, the temperature distribution along the plate length direction was relatively uniform, and 95% of measured final cooling temperature difference from the target temperature 700 ℃ was controlled within ±20 ℃.

关键词: plate , controlled cooling , homogeneous cooling , speed profile , Cholesky decomposition method