OCTOBER 19-20, 2012 - YMCA University of Science & Technology

SLAB WIDTH MEASUREMENT TECHNIQUE USING MANIPULATOR
IN PLATE ROLLING MILL OF BHILAI STEEL PLANT(SAIL)
Anand S. Srivastava 1 , Krishna K. Saxena 2
1 Graduate Student, Department of Mechanical Engineering, B.I.E.T. Jhansi (U.P.)
2 Graduate Student, Department of Mechanical Engineering, B.I.E.T. Jhansi (U.P.)
krishnasxn@gmail.com, +91_9557417310
Abstract
Manipulators are used for proper alignment of slabs and plates before rolling passes begin. Width is a very
important parameter in rolling of the plate, so a precise and reliable method should be introduced to measure the
width of the plate. The manipulators can be used for the measurement of the width with the help of a rack and
pinion arrangement and an encoder-decoderin the existing layout of the plate mill of Bhilai Steel Plant using hydraulic manipulator. A program in C language
has also been developed for design of manipulator pinion or assistance in design process for the same.The thermal
In this paper, a method is suggested for the slab width measurement
analysis using Solid works software has been carried for the manipulator jaw so as to avoid any dimensional
distortion of jaw due to high temperature of slab. This also ensures reliable measurement.
Keywords: Manipulator, rack and pinion, slab.
NomenclatureP=pitch of rack, T= Teeth advanced by rack.
1. Introduction
Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
The function of the manipulator is to align the incoming heated slab (1200 0 C) [1] in order to make the slab to be
perfect perpendicular to the rolling axis and to make zero offset between slab and rolling axis. The manipulator
(Fig 2.) is very essential mechanism in the plate mill since it is used 3000 times a day [2]. In plate mill,
measurement of width of the slab is a critical process because of high temperature of slab. This is done manually
using a holder arrangement with digital display. There are many problems associated with the manual arrangement
of width measurement: (1). The manual measurement process is not a reliable process due to chances of inaccuracy
(2). Due to high temperature of slab the measurement is associated with safety issue.
In order to enhance the productivity of plate mill, width act as a major parameter. Since condition of plain strain is
applicable to the rolling process, therefore very small widening is observed in rolling. So, to produce the plate
conforming the dispatch width as per order, measurement should be done in an accurate manner. In order to attain
the normal width, a proper gap between roll has to be given.The measurement of width is done by the linear motion
of ram or jaws. In other words the gap between the jaws of manipulator (while aligning the slab) is a measurement
of width of the slab. The method focuses on the measurement of rotary motion (Fig 1.). . Hence the linear motion
of the ram has to be converted to rotary motion. The conversion of linear motion of the ram to rotary motion is to be
carried out without any slippage. The basic design processes that have to be carried out are: (1). To attain the
positive drive. (2). To select a suitable device.
Figure 1 BASIC SCHEME OF WIDTH MEASUREMENT
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