Statistical Evaluation of Some Hot Rolling Theories

1982 ◽  
Vol 104 (1) ◽  
pp. 47-52 ◽  
Author(s):  
A. Murthy ◽  
J. G. Lenard

The accuracy and precision of four mathematial models of varying complexity are evaluated by comparing their predictions to experimental data generated in carefully controlled laboratory experiments and to production logs obtained from the finishing trains of several Canadian, American, and European hot strip mills. The materials rolled are low carbon and HSLA steels; the models used are Orowan’s formulation with Shida’s flow strength and Ford and Alexander’s formulation with Shida’s flow strength; then both these formulations are combined with Ekelund’s flow strength equation. It is concluded that Orowan’s formulation with Shida’s flow strength relation is the most consistently accurate technique of analysis. Further, the behavior of HSLA steels is not well described by either Shida’s or Ekelund’s equations.

2018 ◽  
Vol 7 (4.3) ◽  
pp. 35 ◽  
Author(s):  
Volodymyr Kukhar ◽  
Oleksandr Kurpe ◽  
Eduard Klimov ◽  
Elena Balalayeva ◽  
Vladimir Dragobetskii

The paper improves the calculation methodology of metal temperature loss during hot rolling process at continuous mills. The proposed methodology can be implemented at hot strip mills with various in-line equipment arrangements within the temperature ranges appropriate for processes simulation of hot rolling, normalized rolling and Thermo-Mechanical Control Process of carbon and microalloyed steels. It provides engineering analysis of unaccounted temperature losses of feed by means of radiation and convection, which, in the first time, through the time factor, additionally accounts for strip motion speed factors, roller table length and feed length, and also length of rolls contact arc with metal. The accountability of the above mentioned factors in the various compositions depending on the rolling method increases the engineering simulation accuracy, ensures the versatility of the elaborated method with respect to different types of mills and makes the scientific novelty of the study. The equations were developed to calculate the metal temperature loss while coiling at the CoilBox unit. The equations accounts for the influence on the temperature of strip length, coiling and uncoiling speed, strip thickness, inside radius of the reeling coil, the time the feed rests being coiled. The improved model was verified based on actual data. 


2017 ◽  
Vol 746 ◽  
pp. 132-137 ◽  
Author(s):  
Alexander Nam ◽  
Rudolf Kawalla ◽  
Alexander V. Zinoviev ◽  
Yaroslav A. Erisov ◽  
Uwe Prüfert ◽  
...  

The complex thermal modelling approach of the reversing hot strip rolling in connection with a coil model was developed. The coil model provides the modelling of the (un-) and coiling process. The modelling approach is based on object-orientated principals and implemented in MATLAB using library OOPDE and will be the base for the forecasting of the microstructure and the resulting material properties of strip during the reversing hot rolling. The model was validated using experimental data received after carrying out of the 2-pass reversing hot strip rolling of magnesium alloy AZ31. The results show a sufficient correspondence between experimental and calculated temperatures during the 1st and 2nd rolling pass.


2005 ◽  
Vol 500-501 ◽  
pp. 565-572 ◽  
Author(s):  
H. Meuser ◽  
F. Grimpe ◽  
S. Meimeth ◽  
C.J. Heckmann ◽  
C. Träger

This paper deals with the development of low carbon NbTiB micro-alloyed high strength low alloy steel for heavy plates with high wall thickness. In the production of heavy plate it is remarkably difficult to achieve a combination of high strength and good low-temperature toughness. Bainitic microstructures have shown the capability to attain such requirements. To achieve a bainitic microstructure even for heavy wall products the formation of bainite can be promoted and supported by the use of small amounts of boron as a micro-alloying element. This industrial research project is based on the addition of small amounts of boron to promote the desired bainitic structure. Mill rolling trials were carried out to determine the optimum process parameters. The results of experimental mill rolling trials on 35 mm plates will be presented in this paper.


2021 ◽  
Vol 811 ◽  
pp. 141060
Author(s):  
Shilong Liu ◽  
Bin Hu ◽  
Yishuang Yu ◽  
Chengjia Shang ◽  
R.D.K. Misra ◽  
...  

2019 ◽  
Vol 106 (5-6) ◽  
pp. 2227-2241 ◽  
Author(s):  
Patrik Fager ◽  
Martina Calzavara ◽  
Fabio Sgarbossa

AbstractKitting – meaning to supply assembly with components in presorted kits – is widely seen as beneficial for assembly quality and efficiency when there is a multitude of component variants. However, the process by which kits are prepared – the kit preparation – is labour-intensive, and kit errors are problematic at assembly processes. The use of robotics to support kit preparation has received some attention by researchers, but literature is lacking with respect to how collaborative robots – cobots – can support kit preparation activities. The purpose of this paper is to identify the potential of a cobot to support time-efficient batch preparation of kits. To address the purpose, the paper presents a mathematical model for estimation of the cycle time associated with cobot-supported kit preparation. The model is applied in a numerical example with experimental data from laboratory experiments, and cobot-supported kit preparation is compared with manual kit preparation. The findings suggest that cobot-supported kit preparation is beneficial with diverse kits and smaller components quantities per SKU (Stock Keeping Unit) and provides less variability of the outcome, when compared to manual kit preparation. The paper reveals several insights about cobot-supported kit preparation that can be valuable for both academics and practitioners. The model developed can be used by practitioners to assess the potential of cobots to support kit-batch preparation in association with assembly, spare parts, repair and maintenance, or business to business industry.


2001 ◽  
Vol 9 (6) ◽  
pp. 821-830 ◽  
Author(s):  
R.K. Kumar ◽  
S.K. Sinha ◽  
A.K. Lahiri

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