scholarly journals Analysis of the Reasons for the Tearing of Strips of High-Strength Electrical Steels in Tandem Cold Rolling

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7124
Author(s):  
Ivan Petryshynets ◽  
František Kováč ◽  
Ladislav Falat
Keyword(s):  
Cold Rolling ◽  
High Speed ◽  
High Efficiency ◽  
Steel Strip ◽  
High Strength ◽  
Bimodal Distribution ◽  
Dislocation Motion ◽  
Temper Rolling ◽  
Final Thickness ◽  
Tandem Cold Rolling

High-strength non-oriented electro-technical steels with a low thickness possess excellent isotropy of electromagnetic and mechanical properties which is highly required in the production of high-efficiency electric motors. The manufacturing process of this type of steel includes very important and technologically complex routes such as hot rolling, cold rolling, temper rolling, or final heat treatment. The final thickness is responsible for the decrease in eddy-current losses and is effectively achieved during cold rolling by the tandem rolling mill. Industrial production of thin sheets of high-strength silicon steels in high-speed tandem rolling mills is a rather demanding technological operation due to the increased material brittleness that is mainly caused by the intensive solid solution and deformation strengthening processes, making the dislocation motion more complex. The main objective of this work was to investigate the distribution of local mechanical strains through the thickness of high silicon steel hot bands, generated during the cold rolling. The experimental samples were analysed by means of electron back-scattered diffraction and scanning electron microscopy. From the performed analyses, the correlation between the material workability and the nucleation of cracks causing the observed steel strip failure during the tandem cold rolling was characterized. Specifically, the microstructural, textural, misorientation, and fractographic analyses clearly show that the investigated hot band was characterized by a bimodal distribution of ferrite grains and the formation of intergranular cracks took place only between the grains with recrystallized and deformed structures.

scholarly journals Investigation and Optimization of Load Distribution for Tandem Cold Steel Strip Rolling Process

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 677 ◽  
Author(s):  
Xin Jin ◽  
Changsheng Li ◽  
Yu Wang ◽  
Xiaogang Li ◽  
Yongguang Xiang ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Cold Rolling ◽  
Prediction Model ◽  
Load Distribution ◽  
Rolling Mill ◽  
Fitness Function ◽  
Steel Strip ◽  
Rolling Process ◽  
Cold Rolling Mill ◽  
Tandem Cold Rolling

In order to improve the cold rolled steel strip flatness, the load distribution of the tandem cold rolling process is subject to investigation and optimization. The strip deformation resistance model is corrected by an artificial neural network that is trained with the actual measured data of 4500 strip coils. Based on the model, a flatness prediction model of strip steel is established in a five-stand tandem cold rolling mill, and the precision of the flatness prediction model is verified by rolling experiment data. To analyze the effect of load distribution on flatness, the flatness of stand 4 is calculated to be 7.4 IU, 10.6 IU, and 16.8 IU under three typical load distribution modes. A genetic algorithm based on the excellent flatness is proposed to optimize the load distribution further. In the genetic algorithm, the classification of flatness of stand 4 calculated by the developed flatness prediction model is taken as the fitness function, with the optimal reduction of 28.6%, 34.6%, 27.3%, and 18.6% proposed for stands 1, 2, 3, and 4, respectively. The optimal solution is applied to a 1740 mm tandem cold rolling mill, which reduce the flatness classification from 10.8 IU to 3.2 IU for a 1-mm thick steel strip.

Dynamic control of lubrication characteristics in high speed tandem cold rolling

2016 ◽  
Vol 229 ◽  
pp. 407-416 ◽  
Author(s):  
Noriki Fujita ◽  
Yukio Kimura ◽  
Koji Kobayashi ◽  
Kimito Itoh ◽  
Yosuke Amanuma ◽  
...  
Keyword(s):  
Cold Rolling ◽  
High Speed ◽  
Dynamic Control ◽  
Tandem Cold Rolling ◽  
Lubrication Characteristics

High-speed rolling by hybrid-lubrication system in tandem cold rolling mills

2015 ◽  
Vol 216 ◽  
pp. 357-368 ◽  
Author(s):  
Yukio Kimura ◽  
Noriki Fujita ◽  
Yukihiro Matsubara ◽  
Koji Kobayashi ◽  
Yosuke Amanuma ◽  
...  
Keyword(s):  
Cold Rolling ◽  
High Speed ◽  
Lubrication System ◽  
Rolling Mills ◽  
Tandem Cold Rolling ◽  
Cold Rolling Mills

A New Method Predicting Contact Length and Flattening in Temper Rolling

2016 ◽  
Vol 716 ◽  
pp. 605-613 ◽  
Author(s):  
Joonas Ilmola ◽  
Aarne Pohjonen ◽  
Jari Larkiola ◽  
Jari Nylander
Keyword(s):  
Rolling Force ◽  
Steel Strip ◽  
Current Trend ◽  
High Strength Steels ◽  
High Strength ◽  
Work Roll ◽  
Contact Length ◽  
Temper Rolling ◽  
Roll Flattening ◽  
Gap Models

The current trend in temper rolling is to make a small reduction to steel strip in order to achieve higher strength with good formability and toughness. In addition, very high strength steels can be cold rolled twice with very small reductions. This causes problems in setup values for cold rolling. Rolling models are usually overestimating roll flattening in the case of small reductions.In temper rolling thickness reduction is small (0.5 – 3%) and the elastic deformation of the work roll should be taken into account [3]. However, standard circular arc roll gap models (e.g. Bland Ford Ellis combined with Hitchcock model) fail to predict the roll flattening and thus the rolling force [4]. In this work, finite element method has been used to define a simplified model for work roll flattening and contact length. Model describes the effect of reduction, strength of steel strip and roll radius.

Development of High-Speed Rolling Technology by Hybrid-Lubrication System in Tandem Cold Rolling Mill

2013 ◽  
Vol 54 (635) ◽  
pp. 1028-1032 ◽  
Author(s):  
Yukio KIMURA ◽  
Noriki FUJITA ◽  
Yukihiro MATSUBARA ◽  
Koji KOBAYASHI ◽  
Yosuke AMANUMA ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Rolling Mill ◽  
High Speed ◽  
Lubrication System ◽  
Cold Rolling Mill ◽  
Tandem Cold Rolling ◽  
Rolling Technology

scholarly journals System dynamics of a pipe pilger CRM working stand

2019 ◽  
Vol 75 (6) ◽  
pp. 725-734
Author(s):  
S. P. Rakhmanov ◽  
V. V. Povorotniy
Keyword(s):  
Optimal Design ◽  
Cold Rolling ◽  
High Speed ◽  
Rational Design ◽  
System Analysis ◽  
High Efficiency ◽  
Rolling Process ◽  
Calculation Algorithm ◽  
Cold Rolling Mills ◽  
Analysis Of Dynamics

Efficiency of the pilger cold rolling of pipes process realization can be increased both by perfection of the rolling process and by a selection of rational parameters of the base technological equipment and the mills functioning regimes. Particular attention should be paid to the increase of reliability of functioning, increase of high-speed and productivity of pipe cold rolling mills (CRMs). Results of the system analysis of dynamics of pipe CRM working stand of various designs presented. A calculation algorithm elaborated and differential equations of the pipe CRM working stand obtained. Pictures of dynamic motions for selected pipe CRM working stand obtained. The analysis of theoretical studies showed, that for stabilization of the stand base elements it is necessary to increase the rigidity of the working stand correspondent elements. It was shown, that the stand rigidity increase reached by arrangement longitudinal bridge of variable thickness, connecting the internal and external structure’ casing. An optimal design roller actuator elaborated. Implementation of the actuator will enable to accomplish the technological process more effectively, since the unit’ elements can adopt all possible inaccuracy of the working stand manufacturing and assembling, as well as housing post deformation. It was ascertained, that the roller actuator of optimal design, above all, plays a role of an emergency gear of the pipe CRM working stand. The studies revealed that increase of productivity and quality of the manufactured products reached mainly by application of the working stand of rational design at the pipe CRM. The industrial running the modified variant of working stand design during eight years to roll hard-deformed steels and alloys confirm its high efficiency at production of precision high quality pipes.

Estimation model of plate-out oil film in high-speed tandem cold rolling

2015 ◽  
Vol 219 ◽  
pp. 295-302 ◽  
Author(s):  
Noriki Fujita ◽  
Yukio Kimura ◽  
Koji Kobayashi ◽  
Yosuke Amanuma ◽  
Yasuhiro Sodani
Keyword(s):  
Cold Rolling ◽  
High Speed ◽  
Estimation Model ◽  
Oil Film ◽  
Tandem Cold Rolling

Experimental Study on Surface Integrity in High-Speed End Milling of Titanium Alloy TB6

2013 ◽  
Vol 328 ◽  
pp. 867-871 ◽  
Author(s):  
Dao Xia Wu ◽  
Chang Feng Yao ◽  
Liang Tan ◽  
Jun Xue Ren ◽  
Ding Hua Zhang
Keyword(s):  
Titanium Alloy ◽  
Surface Integrity ◽  
High Speed ◽  
High Efficiency ◽  
End Milling ◽  
High Strength ◽  
Wall Structure ◽  
Thin Wall ◽  
High Speed Milling ◽  
Good Surface

High-speed milling of titanium alloy is widely used in aviation and aerospace industries for its high efficiency and good quality. In order to obtain good surface integrity, experiments of high-speed end milling were performed to investigate the influence of milling parameters on surface integrity. The results show that the surface roughness, surface topography, residual stresses and microhardness are significantly affected by feed per tooth and milling speed. Good surface state was obtained when feed per tooth, milling speed, milling width and milling depth is close to 0.08mm/z, 100m/min, 7mm, and 0.2mm respectively. High-speed milling is favourable for improving machining efficiency and surface quality and therefore should be widely used in manufacturing of aircraft thin-wall structure parts. This study provides a theoretical basis and experimental evidence for the surface integrity of machined high-strength alloy.

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