scholarly journals Ultrasonic roll bite measurements in cold rolling – Roll stress and deformation

2017 ◽  
Vol 249 ◽  
pp. 1-13 ◽  
Author(s):  
Y. Carretta ◽  
A.K. Hunter ◽  
R. Boman ◽  
J.-P. Ponthot ◽  
N. Legrand ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Rolling Roll ◽  
Stress And Deformation ◽  
Cold Rolling Roll ◽  
Roll Bite

scholarly journals Ultrasonic roll bite measurements in cold rolling: Contact length and strip thickness

2017 ◽  
Vol 232 (2) ◽  
pp. 179-192 ◽  
Author(s):  
Yves Carretta ◽  
Andrew Hunter ◽  
Romain Boman ◽  
Jean-Philippe Ponthot ◽  
Nicolas Legrand ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Rolling Mill ◽  
Work Roll ◽  
Contact Length ◽  
Strip Thickness ◽  
Rolling Contact ◽  
Thickness Variation ◽  
Rolling Load ◽  
Process Measurements ◽  
Roll Bite

In cold rolling of thin metal strip, contact conditions between the work rolls and the strip are of great importance: roll deformations and their effect on strip thickness variation may lead to strip flatness defects and thickness inhomogeneity. To control the process, online process measurements are usually carried out; such as the rolling load, forward slip and strip tensions at each stand. Shape defects of the strip are usually evaluated after the last stand of a rolling mill thanks to a flatness measuring roll. However, none of these measurements is made within the roll bite itself due to the harsh conditions taking place in that area. This paper presents a sensor capable of monitoring strip thickness variations as well as roll bite length in situ and in real time. The sensor emits ultrasonic pulses that reflect from the interface between the roll and the strip. Both the time-of-flight of the pulses and the reflection coefficient (the ratio of the amplitude of the reflected signal to that of the incident signal) are recorded. The sensor system was incorporated into a work roll and tested on a pilot rolling mill. Measurements were taken as steel strips were rolled under several lubrication conditions. Strip thickness variation and roll-bite length obtained from the experimental data agree well with numerical results computed with a cold rolling model in the mixed lubrication regime.

Development of Mixed Lubrication Cold Rolling Model

2015 ◽  
Vol 642 ◽  
pp. 190-195
Author(s):  
Yhu Jen Hwu ◽  
Jian Ting Lee ◽  
Yeau Ren Jeng
Keyword(s):  
Cold Rolling ◽  
High Surface ◽  
Work Roll ◽  
Mixed Lubrication ◽  
Rolled Strip ◽  
Base Oil ◽  
Roll Deformation ◽  
Inlet Zone ◽  
Quality Surface ◽  
Roll Bite

Within past 20 years, high surface qualities of cold strip were demanded by automotive industry and electrical engineering. Main purposes of cold rolling processed are to provide high quality surface and generate appropriate roughness for different customs. Emulsion is a common coolant used in cold rolling processes, Properties of base oil in emulsion, concentration, roughness of work roll, rolling speed and reduction are important parameters, which dominate the surface qualities of cold rolled strip. Hence, a powerful cold rolling model which can describe complicate tribological behavior in roll bite is required. In this article, a cold rolling model which integrates roll deformation and mixed lubrication in inlet zone and biting area was developed. The thickness of oil film, fraction of contact area and coefficient of friction in roll bite are calculated.

Nonlinear Dynamic Analysis of a Parametrically Excited Cold Rolling Mill

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Sajan Kapil ◽  
Peter Eberhard ◽  
Santosha K. Dwivedy
Keyword(s):  
Cold Rolling ◽  
Frequency Response ◽  
Governing Equation ◽  
Rolling Mill ◽  
Nonlinear Dynamic Analysis ◽  
Equation Of Motion ◽  
Horizontal Load ◽  
Cold Rolling Mill ◽  
Parametrically Excited ◽  
Roll Bite

In this work, a four high cold rolling mill is modeled as a spring-mass-damper system considering horizontally and vertically applied time-dependent forces due to the interaction between the strip and the working rolls. The effect of vibration of the moving strip on the work roll vibration is also considered for developing the governing equation of motion of the system which is found to be that of a nonlinear parametrically excited system. The governing equation of motion is solved by using the method of multiple scales to find the instability regions and frequency-response curves of the system. The critical amplitude of horizontal load in roll bite is calculated and the frequency-response is studied in detail considering the effect of various process parameters, such as velocity, thickness of strip, time delay, amplitude, and frequency of horizontal load in roll bite. This work can find application in the design and development of high speed and chatter free rolling mills.

Local Variations of Strain and Strain Rate in Roll Bite Region During Rolling of Steels

1998 ◽  
Vol 120 (1) ◽  
pp. 86-96 ◽  
Author(s):  
Ampere A. Tseng ◽  
Shi R. Wang ◽  
A. C. W. Lau
Keyword(s):  
Finite Element ◽  
Cold Rolling ◽  
Strain Rate ◽  
Hot Rolling ◽  
Numerical Approach ◽  
Spatial Variations ◽  
Rate Variation ◽  
Strain And Strain Rate ◽  
Before And After ◽  
Roll Bite

A combined experimental-numerical approach has been developed to quantify the strain rate variation of the workpiece in the roll bite region. In this approach, cold rolling experiments at a production mill were conducted first. Then tensile and microhardness tests were performed on workpieces before and after cold rolling to establish the relationship between the microhardness and plastic strain of the material. Microhardness measurements were also conducted in the roll bite region on a partially cold rolled workpiece. A finite element rolling simulation was performed to predict the spatial variations of the strain and strain rate. Through microhardness matching, it was found that the finite-element predicted strains agree very well with those actually existing in the rolled workpiece. Consequently, the finite-element predicted strain rates, whose time-accumulation directly gave strains which matched the actual strains, were verified. Finally, a finite-element simulation of both cold and hot rolling was conducted to assess the effect of several major rolling parameters on the strain rate variation in the bite region. Results show that the spatial variations of strain rate in the roll bite region are extremely nonuniform for both cold and hot rolling.

Roll bite conditions controlling formation of wear debris during cold rolling of aluminum

1994 ◽  
Vol 45 (1-4) ◽  
pp. 117-124 ◽  
Author(s):  
K.R. Januszkiewicz ◽  
G. Stratford ◽  
T. Ward
Keyword(s):  
Cold Rolling ◽  
Wear Debris ◽  
Roll Bite

Estimated Roll Bite Temperatures Encountered in Cold Rolling, and Their Effect in Rolling

1967 ◽  
Vol 89 (3) ◽  
pp. 471-476 ◽  
Author(s):  
H. Inhaber
Keyword(s):  
Cold Rolling ◽  
Strain Rate ◽  
Rolling Mill ◽  
Mathematical Formulation ◽  
Rolling Process ◽  
Cold Rolling Strip ◽  
Rolling Strip ◽  
Roll Bite

In modern cold rolling, strip exit velocities of the order of thousands of feet per minute are employed. Even if only moderate reductions of the strip are performed, large amounts of heat are generated due to deformation and friction. This work presents a mathematical formulation of the problem of the temperature in the roll bite as strain rate is varied (due to Cerni), as well as some calculated examples using a typical small rolling mill. The possible influence of the temperature generated on the rolling process is also considered.

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