Keywords: Chatter, Principal Component Analysis (PCA), cold rolling, vibration 1. INTRODUCTION In cold roll mill alternate dark & bright bands are often observed on rolled strip surface along the length of the coil perpendicular to rolling direction. These bands on strip surface are called chatter mark defect shown in Fig. 1.
Thread Rolling Figure 13.16 (a) Features of a machined or rolled thread. (b) Grain flow in machined and rolled threads. Unlike machining, which cuts through the grains of the metal, the rolling of threads causes improved strength, because of cold working and favorable grain flow. Figure 13.15 Thread-rolling processes: (a) and (c) reciprocating
The cold rolling process is a high speed, transient, and time-related metal machining molding process [1]. As cold rolling mill is a multimass and rotary motion object system, the vibration as an implicit factor commonly exists in the course of its operation, but it usually does not apparently present due to the conditional constraints of ...
Chatter vibrations were investigated for the high speed 5 stand 4-h tandem cold rolling mill 2030 of the NLMC. Real-time chatter vibration monitoring and diagnostics system was developed and ...
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Our blog ' Mill Vibration Phenomena during Cold Rolling ' describes the different modes of mill vibration. Third octave gauge chatter and fifth octave chatter are two common forms of mill vibration that are difficult to solve. Both can cause significant strip quality issues if …
The MillSlicer utilises vibration sensors and digital signal processing technology to provides information Mill Vibration Phenomena during Cold Rolling - Innoval ...,The simplest type of mill vibration is found in all mills. It is a forced vibration due to roll eccentricity and so occurs at roll rotation frequencies.
BRUSA E, LEMMA L, BENASCIUTTI D. Vibration analysis of a Sendzimir cold rolling mill and bearing fault detection[J]. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2010, 224(8): 1645–1654.
rolling mill coupling vibration. Yun et al. [ ] proposed a model which allows rolls to vibrate along two orthogonal directions to study the vertical-horizontal coupling vibra-tion and suggested that mode coupling might also induce vibration. Since the vibration of a high-speed rolling mill always appears as the coupling of multiple vibration types,
Mill vibrations (chatter) especially occurring at high rolling speeds affect product quality of the cold-rolled material and thus lead to yield losses and quality issues. Among other supportive measures active chatter damping has turned out to be an effective approach to counteract these problems by significantly reducing vibration issues of ...
Mill vibration during cold rolling. February 2007. T. Farley; In common with other rotating machines, rolling mills are prone to many different vibrations during rolling and most do …
Zheng et al. (2017) established a spatial vibration model of a six-high cold strip rolling mill based on multi-body transfer matrix method, and demonstrated the vibration characteristics of the mill. Recently, several attempts have been made to analyze chatter characteristics in tandem rolling mills, especially the effect of friction on vibration.
On account of the self-excited vibration in No. 5 stand of 1420 cold rolling mill, the relationship between rolling lubrications and self-excited vibration of rolling mill was theoretically studied. The self-excited vibration in No.5 stand of the mill was restrained by optimizing the lubrication technical parameters, and the critical stabilized rolling speed was increased from650 m/min to ...
Due to this issue, along with the nonstationary character of rolling and rolling mill load regime, rolling with tension may transform into rolling with pressure, which results in enhanced energy consumption, while a rapid change in rolling with pressure and tension may lead to the emergence of adverse self-excitation vibrations on cold rolling ...
A rolling mill that includes the driving system was modeled by multibody dynamics to investigate the cause and characteristics of the chatter vibration. The proposed numerical model was validated by theoretical analysis and an experiment that was carried out during manufacturing.
Statistical analysis of the rolling parameters during the vibration of the five-cell cold rolling mill was conducted by Makarov et al. [7]. Brusa and Lemma [8] analyzed the dynamic effects in ...
Rolling mill vibration is a technical problem in the iron and steel industry for many years and has serious impact and harm on production. There were serious vibrations in the middle mills when rolling thin container strip for the compact strip production (CSP) strip hot rolling process. This paper studied the hysteretic characteristic of rolled strip and established …
chatter vibration can affect both the quality and production capacity of cold rolled steel if it is not properly monitored and reduced. 3rd order octave chatter is a self-generating resonance...
Models for the occurrence of the vibrational instability during rolling known as third octave chatter are presented and discussed. An analysis of rolling mill chatter was performed for the purpose of identifying characteristics of the vibrations and to determine any dependency on the rolling schedule.
The rolling mill vibration is characterized by the coupling effects among mechanical, electrical, hydraulic and interfacial subsystems. The influence of the mill modulus control gain in automatic gauge control on the vibration in hot rolling mills was investigated. Firstly, an experiment related to the mill modulus control gain was carried out in the hot …
and 150Hz, is a self-excited vibration phenomena typically occurring in the rear stands of tandem cold mills. It can produce significant gauge variations and even cause strip breaks. 3rd octave mill chatter is characterized by a quickly diverging vertical vibration of the rolls for specific rolling conditions (material, mill speed, forces,
Drives for cold rolling mills. Characteristic of cold rolling mills is their operation over an extremely large range of speeds reaching up to 2,000 m/min. That's why the main drive units often comprise change-speed gears with two transmission stages. This provides a correspondingly wide speed range. The spur gears and mill pinion gears are ...
Mill chatter in tandem cold rolling mill is a major rejection to the quality and production of the strips. In most mill vibration models, either the roll mass is usually limited to vibrate in vertical direction and vertical-horizontal directions, or the multiple rolls system is simplified to a single mass system. However, the torsional chatter is also a typical type of mill chatter, and the ...
to vibration with a very low resonance frequency. The stator core is constructed with ... torque in order to prevent loosening of constituent parts during heavy impact loads in the rolling mill and/or frequent reversing operations. Such preventative measures ... • Example: Motors used for continuous hot strip mills, cold tandem mills, cold
Dynamic behaviour of cold rolling mill with unsteady lubrication roll-gap interface during sheet... 00:00:00 This paper presents the results of developing a vibration model for the rolling mill vertical system with respect to the roll gap under the unsteady lubrication conditions to address the frequently self-excited vibration ...
elastoplastic deformation during cold rolling and its surface quality. MODEL DESCRIPTION In order to reveal the mechanism of defects occur-rence on the surface of steel cold rolled strips during work rolls vibration, the finite element method imple-mented in the DEFORM-2D program was used. The 4th stand of the 5-stand mill 1700 of PAO Severstal ...
A basic theory of chatter in. cold rolling is presented which is based on the effect of the variable scrip tension on the rolling force as well as on the variations of contact length The structure of a computer program simulating chatter of a tandem mill is presented and examples given of the effect of rolling speed, strip width, coefficient of friction and of using a tuned damper.
3.1. Vibration Measurement of the Rolling Mill The cold rolling process is usually conducted with a workpiece that is initially at room temperature. A schematic illustration of the 6-high cold rolling mill is shown in Fig. 1.11) The stands are arranged to produce a sequential reduc-tion in the thickness of the strip. Work rolls are the tools
Layout of a 5-stand tandem cold rolling mill. Chatter can be regarded as a type of self-excited vibration. Because interactions occur between the structural dynamics of the mill and the rolling process, this phenomenon is subsequently observed when the external excitation force changes the roll gap and rolling speed.
Mill Vibration Phenomena during Cold Rolling All machines vibrate during operation. However, only a few of these vibrations cause problems to the …
In common with other rotating machines, rolling mills are prone to many different vibrations during rolling and most do not cause a problem. However, there are several types of rolling mill vibration that can have a significant impact on the quality …
The vertical vibration mechanism of cold rolling mill is studied under the influence of the dynamic friction mechanism between the workpiece and roll. Fan et al. introduced the Duffing oscillator and the parameters of the excitation system and established the roll system vertical vibration model [ 12 ].
The presence of several rolls in cluster cold rolling mills makes on-line vibration monitoring and failure analysis difficult. The dynamic behaviour of rolls strongly depends on the rolling pressure in the roll bite. Strip vibration applies a dynamic component on the rolling force acting on the work roll and may excite the resonance of the mill ...
Keywords: rolling mill vibration, coupling dynamic model, AGC, mill modulus control gain. 1. Introduction The mill vibration has become a bottleneck in the thin steel strip manufacturing [1, 2], as the mill vibration can cause unacceptable product quality degradation in the steel strip, and even severely damage the mill equipment [3, 4].
Gong et al. made a numerical simulation of the roll vibration during the cold rolling in 6-roll mill, and through the analysis of the results, it was considered that the vibration had the minimum value when the rolling speed was 25 m/s. With the further improvement of the flatness standard on the market, as the most mature high-precision cold ...
