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
LIU Yun-fei
,
PENG Yan
,
LIU Hong-min
,
ZHANG Jian
钢铁研究学报(英文版)
According to the research on the deformation resistance and the ferrite transformation behavior of X80 pipeline steel by using Gleeble-3500 thermal simulator, a mathematical model of the α-phase start transformation temperature for high-Nb pipeline steel was established, based on the transformation kinetics and thermodynamics. The influence of deformation and cooling rate as well as Nb content on the α-phase starting temperature was thoroughly investigated. The results given by the model were in good agreement with the experimental results, which showed that the model could predict the α-phase starting temperature for high-Nb pipeline steel during cooling process.
关键词:
high-Nb pipeline steel
,
hot deformation
,
deformation resistance
,
cooling rate
,
ferrite transformation temperature
ZHANG Jian
,
PENG Yan
,
LIU Hong-min
,
LIU Yun-fei
钢铁研究学报(英文版)
Abstract： To investigate the wear resistance of ZG42CrMo in industrial application, the wear behaviors under different normal loads, sliding speeds and ambient temperatures were simulated by an MMU-5G abrasion tester to acquire the friction coefficients and wear rates, with the morphology of worn surface observed by scanning electron microscopy (SEM) and chemical composition of worn surface and debris analyzed by X-ray energy dispersive spectroscopy (EDS). Combine with the theory of tribology, finally the regular of environmental factors′ influence on material wear behaviors is determined. The results show that the increase of load decreases wear resistance significantly, when the pressure reaches a certain extent, severe spalling occurs on the worn surface; the changes of speed result in the changes of size of abrasive debris, and then effect the wear behaviors, in the increasing process of speed, the wear rate increases firstly and then decreases; the rise of temperature causes changes in wear mechanism, bring forth oxidation film on the worn surface, which leads to significant improvement of the wear resistance of materials under high temperature compared to that under low temperature.
关键词:
Key words: ZG42CrMo
,
wear resistance
,
normal load
,
sliding speed
,
ambient temperature
WANG Dong-cheng
,
LIU Hong-min
钢铁研究学报(英文版)
The shape of strip is calculated by iterative method which combines strip plastic deformation model with rolls elastic deformation model through their calculation results, which can be called results coupling method. Because the shape and rolling force distribution are very sensitive to strip thickness transverse distribution′s variation, the iterative course is rather unstable and sometimes convergence cannot be achieved. In addition, the calculating speed of results coupling method is low, which restricts its usable range. To solve the problem, a new model coupling method is developed, which takes the force distribution between rolls, rolling force distribution and strip′s exit transverse displacement distribution as basic unknowns, and integrates strip plastic deformation model and rolls elastic deformation model as a unified linear equations through their internal relation, so the iterative calculation between the strip plastic deformation model and rolls elastic deformation model can be avoided. To prove the effectiveness of the model coupling method, two examples are calculated by results coupling method and model coupling method respectively. The results of front tension stress, back tension stress, strip′s exit gauge, the force between rolls and rolling force distribution calculated by model coupling method coincide very well with results coupling method. However the calculation course of model coupling method is more steady than results coupling method, and its calculating speed is about ten times as much as the maximal speed of results coupling method, which validates its practicability and reliability.
关键词:
shape prediction
,
results coupling method
,
model coupling method
,
strip plastic deformation
,
rolls elastic deformation
SUN Jian-liang
,
PENG Yan
,
LIU Hong-min
钢铁研究学报(英文版)
Take the moving strip between two stands of some cold tandem rolling mill in rolling process as subject investigated, according to the Poisson-Kirchhoff sheet theory, the vibration model of the moving strip in the rolling process was established. Model of distributed stress was built based on rolling theory. And then, vibration model of moving strip with distributed stress was established. The partial differential equation was discreted by Galerkin truncation. The natural frequency and stability of the moving strip were investigated and simulation in time domain was made by numerical method. Take the moving strip between the second stand and third stand of some 1660 tandem mill as subject investigated, distributions of stress, natural frequencies and stability of moving strip were determined under six different rolling conditions which are “uniform distribution of stress”, “flat roll flat”(crown of entrance strip and crown of exit strip are all 0 at the second mill), “flat roll convex”(crown of entrance strip is 0 and crown of exit strip is 20μ), “flat roll concave”(crown of entrance strip is 0 and crown of exit strip is -20μ), “convex roll flat”(crown of entrance strip is 20μ and crown of exit strip is 0) and “concave roll flat”(crown of entrance strip is -20μ and crown of exit strip is 0). At last, three-dimension dynamic simulation was made, the moving law of the strip was determined. This model can be used to study the stability of moving strip, depress the shape wave of strip and develop new rolling technology from the aspect of dynamics theory.
关键词:
Moving strip;Distributed stress;Galerkin truncation method;Poisson-Kirchhoff sheet theory;Stability
SHAN Xiu-ying
,
LIU Hong-min
,
JIA Chun-yu
钢铁研究学报(英文版)
Flatness is an important equality indicator of strip rolling and roll sub-sectional cooling is an important method for flatness control, especially for high order flatness component control. It is very hard to build the mathematic model of roll sub-sectional cooling because of its characteristics of nonlinearity, hysteresis quality and strong coupling etc. In order to improve the control effect of roll sub-sectional cooling control model, the roll sub-sectional cooling adaptive fuzzy control model based on fuzzy model inversion is built according to the separation principle of fuzzy form on the basis of the conventional fuzzy control model, where the parameters of the fuzzy controller can be dynamically regulated according to the change of rolling conditions. Simulation experiment results of the model indicate that the proposed roll sub-sectional cooling adaptive fuzzy control model based on fuzzy model inversion has high control precision and rapid response speed with strong self-learning and anti-interference capacity and a new method is provided for high-precision flatness control.
关键词:
fuzzy identification;sub-sectional cooling;adaptive;fuzzy control;flatness control
