scholarly journals MODELING ROLLERS USING TERRESTRIAL LIDAR POINTS IN A HOT-ROLLING STEEL MILL

2021 ◽  
Vol XLIV-M-3-2021 ◽  
pp. 29-36
Author(s):  
S. S. Deshpande ◽  
M. Falk ◽  
N. Plooster
Keyword(s):  
Hot Rolling ◽  
Rotation Axis ◽  
Moving Average ◽  
Single Point ◽  
Coordinate Frame ◽  
Steel Mill ◽  
Terrestrial Lidar ◽  
Binary Images ◽  
Steel Mills ◽  
Steel Slab

Abstract. Terrestrial lidar scanners are increasingly being used in numerous indoor mapping applications. This paper presents a methodology to model rollers used in hot-rolling steel mills. Hot-rolling steel mills are large facilities where steel is processed to different shapes. In a steel sheet manufacturing process, a steel slab is reheated at one end of the mill and is passed through multiple presses to achieve the desired cross-section. Hundreds of steel rollers are used to transport the steel slab from one end of the mill to the other. Over a period of use, these rollers wore out and need replacement. Manual determination of the damage to the rollers is a time-consuming task. Moreover, manual measurements can be influenced by the operator’s judgment. This paper presents a methodology to model rollers in a hot-rolling steel mill using lidar points. A terrestrial lidar scanner was used to collect lidar points over the roller surfaces. Data from several stations were merged to create a single point cloud. Using a bounding box, lidar points on all the rollers were clipped and used in this paper. The clipped data consisted of the roller as well as outlier points. Depending on the scan angles of scanner stations, partial surfaces of the rollers were scanned. A right-handed coordinate frame was used where the X-axis passed through the centers of all the rollers, Y-axis was parallel to the length of the first roller, and the Z-axis was in the plumb direction. Using a standard diameter of the roller, model roller points were created to extract the rollers. Both the lidar data and the model points were converted to rectangular prism-shaped voxels of dimensions 15.24 mm (0.05 ft) × 15.24 mm in the X and Z directions and extending over the entire width of the roller in the Y-direction. Voxels containing at least 40 lidar points were considered valid. Binary images of both the lidar points and the model points were created in the X-Z axes using the valid voxels. The roller locations in the lidar image were located by performing 2D FFT image matching using the model roller image. The roller points at the shortlisted locations were fitted with a circle equation to determine the mean roller diameters and mean center locations (roller’s rotation axis). The outlier points were filtered in this process for each roller. The elevation at the top of every roller was determined by adding their radii and Z-coordinates of its centers. Incorrectly located and/or modeled rollers were identified by implementing moving-average filters. Positively identified roller points were further analyzed to determine surface erosions and tilts. The above methodology showed that the rollers can be effectively modeled using the lidar points.

Semi-Automated Roller Parameters Extraction from Terrestrial Lidar

2021 ◽  
Vol 87 (12) ◽  
pp. 879-890
Author(s):  
Sagar S. Deshpande ◽  
Mike Falk ◽  
Nathan Plooster
Keyword(s):  
Rotation Axis ◽  
Moving Average ◽  
Three Dimensional ◽  
Data Sets ◽  
Steel Mill ◽  
Data Set ◽  
Terrestrial Lidar ◽  
Two Dimensional Image ◽  
Average Rotation

Rollers are an integral part of a hot-rolling steel mill. They transport hot metal from one end of the mill to another. The quality of the steel highly depends on the surface quality of the rollers. This paper presents semi-automated methodologies to extract roller parameters from terrestrial lidar points. The procedure was divided into two steps. First, the three-dimensional points were converted to a two-dimensional image to detect the extents of the rollers using fast Fourier transform image matching. Lidar points for every roller were iteratively fitted to a circle. The radius and center of the fitted circle were considered as the average radius and average rotation axis of the roller, respectively. These parameters were also extracted manually and were compared to the measured parameters for accuracy analysis. The proposed methodology was able to extract roller parameters at millimeter level. Erroneously identified rollers were identified by moving average filters. In the second step, roller parameters were determined using the filtered roller points. Two data sets were used to validate the proposed methodologies. In the first data set, 366 out of 372 rollers (97.3%) were identified and modeled. The second, smaller data set consisted of 18 rollers which were identified and modelled accurately.

scholarly journals Analysis and prediction of polar motion using MSSA method

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Xin Jin ◽  
Xin Liu ◽  
Jinyun Guo ◽  
Yi Shen
Keyword(s):  
Polar Motion ◽  
Rotation Axis ◽  
Moving Average ◽  
Singular Spectrum Analysis ◽  
Autoregressive Moving Average ◽  
Rotational Axis ◽  
Autoregressive Moving Average Model ◽  
System Service ◽  
Moving Average Model ◽  
Polar Motion Prediction

AbstractPolar motion is the movement of the Earth's rotational axis relative to its crust, reflecting the influence of the material exchange and mass redistribution of each layer of the Earth on the Earth's rotation axis. To better analyze the temporally varying characteristics of polar motion, multi-channel singular spectrum analysis (MSSA) was used to analyze the EOP 14 C04 series released by the International Earth Rotation and Reference System Service (IERS) from 1962 to 2020, and the amplitude of the Chandler wobbles were found to fluctuate between 20 and 200 mas and decrease significantly over the last 20 years. The amplitude of annual oscillation fluctuated between 60 and 120 mas, and the long-term trend was 3.72 mas/year, moving towards N56.79 °W. To improve prediction of polar motion, the MSSA method combining linear model and autoregressive moving average model was used to predict polar motion with ahead 1 year, repeatedly. Comparing to predictions of IERS Bulletin A, the results show that the proposed method can effectively predict polar motion, and the improvement rates of polar motion prediction for 365 days into the future were approximately 50% on average.

A Model to Minimize the Hot Rolling Time of a Steel Slab Considering the Steel’s Chemical Composition

2008 ◽  
pp. 471-480
Author(s):  
Carlos A. Hernández Carreón ◽  
Héctor J. Fraire-Huacuja ◽  
Karla Espriella Fernandez ◽  
Guadalupe Castilla-Valdez ◽  
Juana E. Mancilla Tolama
Keyword(s):  
Chemical Composition ◽  
Hot Rolling ◽  
Steel Slab

An analysis of workplace exposures to asbestos at three steel mills located in the United States (1972-1982)

2019 ◽  
Vol 35 (11-12) ◽  
pp. 726-737
Author(s):  
Dana Hollins ◽  
Amanda Burns ◽  
Ken Unice ◽  
Dennis J Paustenbach
Keyword(s):  
Occupational Safety ◽  
Weighted Average ◽  
Open Hearth ◽  
The United States ◽  
Blast Furnaces ◽  
Health Administration ◽  
Steel Mill ◽  
Exposure Limits ◽  
Steel Mills ◽  
Safety And Health

The objective is to present historical asbestos airborne concentrations associated with activities involving presumably asbestos-containing materials in steel mills. A total of 138 historical industrial hygiene air samples collected in three US steel mills from 1972 to 1982 were analyzed. The majority of samples were collected during relining of open hearth furnaces, stoves, and blast furnaces by steel mill bricklayers and bricklayer helpers. Over 75% of the samples ( n = 106) were collected for 50 min or less, four samples were collected for 227 to 306 min, and sample durations were not reported for the remaining 28 samples. Average airborne fiber concentrations measured during relining activities of open hearth furnaces, stoves, and blast furnaces were 0.21 f/cc, 0.72 f/cc and 0.13 f/cc phase-contrast microscopy (PCM), respectively. Measured airborne fiber concentrations of four time-weighted average (TWA) samples (>227 min) averaged 0.045 f/cc. Estimated 8-h TWAs concentrations averaged 0.34 f/cc for bricklayers and 0.2 f/cc bricklayer helpers. While 8-h TWA concentration estimates for monitored tasks/jobs may often have exceeded current Occupational Safety and Health Administration (OSHA) Permissible Exposure Limits (PELs), they did not exceed relevant contemporaneous occupational exposure standards. This analysis provides a better understanding of historical airborne asbestos exposures that bricklayers and other tradesmen experienced during furnace and stove work in the US steel mills.

scholarly journals Optimal multilevel control of hot rolling steel mills

1977 ◽  
Vol 10 (14) ◽  
pp. 271-276
Author(s):  
G.M. Aly ◽  
M.M. Aziz ◽  
M.A.R. Ghonaimy
Keyword(s):  
Hot Rolling ◽  
Steel Mills

Numerical Analysis of Thermal Stress Development of Steel Slabs in a Pusher-Type Reheat Furnace

2020 ◽  
Author(s):  
Francisco J. Martinez Zambrano ◽  
Bethany Worl ◽  
Xiang Li ◽  
Armin K. Silaen ◽  
Nicholas Walla ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Hot Rolling ◽  
Radiant Heat ◽  
Rolling Process ◽  
Radiant Heat Transfer ◽  
Steel Product ◽  
Stress Development ◽  
Reheat Furnace ◽  
Hot Rolling Process ◽  
Steel Slab

Abstract During the steelmaking and hot rolling processes, various defects and cracks appear throughout the steel product. These cracks may initiate and grow throughout the hot rolling process and result in a lower quality of the product than is acceptable. The most energy-intensive part of the hot rolling process is the reheating furnace, where slabs are heated up to a target rolling temperature largely through radiant heat transfer. In the reheat furnace, large stresses may develop due to the thermal gradients within the steel product. A thermal-stress analysis is proposed based on finite element method (FEM) to study the impacts of charging temperature, slab velocity, and heating rate on stress development as the steel slab travels through an industrial pusher-type reheat furnace. Furnace zone information is taken from a previously validated computational fluid dynamics (CFD) model and applied as thermal boundaries and constraints within the thermal-stress FEM models. Temperature and stress results were taken at the core, top, bottom, top quarter, and the bottom quarter of the steel slab at different residence times. Moreover, temperature lines and contour plots taken along the length of the slab allow visualization of the gradual development of temperature and identification of the locations corresponding to temperature variations as the slabs move in the furnace. The slab temperature predicted by the FEM model was found valid when compared with industrial data. Stress predictions found similar trends with previously published works as well as evidence of thermal shock in the sub-surface near the beginning of the residence time.

The Role of Constitutive Formulation in the Analysis of Hot Rolling

1987 ◽  
Vol 109 (4) ◽  
pp. 343-349 ◽  
Author(s):  
J. G. Lenard ◽  
F. Wang ◽  
G. Nadkarni
Keyword(s):  
Hot Rolling ◽  
Constitutive Modelling ◽  
Material Behavior ◽  
Steel Mill ◽  
Flow Strength ◽  
Strength Data ◽  
Flat Rolling ◽  
Constitutive Formulation

The effect of constitutive modelling of material behavior on the predictive abilities of two models of flat rolling is studied. Comparison of calculated roll forces and powers to those measured on a commerical steel mill indicates that the Orowan model is sufficiently accurate when supplied with carefully determined flow strength data. The manner of representation of that data is found to be significant. The results show that a multidimensional databank, which stores values of strength for specific strains, rates of strain and temperatures is very useful in modelling the process.

scholarly journals Seasonal Variability of Lightning Activity in Yakutia in 2009–2019

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 918
Author(s):  
Lena Tarabukina ◽  
Vladimir Kozlov
Keyword(s):  
Moving Average ◽  
Single Point ◽  
Low Frequency ◽  
Lightning Activity ◽  
Entire Area ◽  
Direction Finder ◽  
Seasonal And Diurnal Variations ◽  
Number Variation ◽  
Lightning Discharges ◽  
Total Lightning

The instrumental continuous monitoring of lightning activity in Yakutia has been carried by the lightning direction finder since the 2000s. Devices for detection of sferic (very low frequency radio pulses emitted by lightning discharges) in Yakutia were supplemented in 2009 with relatively short-range (effective detection radius up to 480 km) single-point Stormtracker and LD-250 direction finders from Boltek Corporation (Welland, ON, Canada). The Stormtracker gives a slightly overestimated ratio of CG strokes due to the amplitude threshold of a single-point direction finder, but the device has not changed over the years, which allows for the consideration of the annual dynamics of parameters. In 2009, a sensor in Yakutsk was included in the World Wide Lightning Location Network (WWLLN). The seasonal and diurnal variations of the total lightning stroke number in the central part and the entire area of Yakutia were obtained (up to 1200 km in radius and limited by latitude–longitude boundaries of 105–150° E, 55–75° N). The longest thunderstorm seasons are often observed in the southern part of Yakutia. There was a slight increase in the duration of the thunderstorm season until 2015 in the central part of Yakutia. The interannual variations in the total number of lightning strokes showed periodic fluctuations (with a period of about three years) over the whole area of Yakutia. The periods of high lightning activity shifted within a season from year to year, as revealed by the monthly stroke number variation. Thus, the maximum lightning rate occurred at the beginning of summer, in the middle or at the beginning of August, and had a period of about three years. Every summer, there were 2–3 periods of high lightning activity, resulting from the moving average with a two-week window (according to the longest duration of cyclones). If the periods of high lightning activity shifted toward the beginning of summer, a decrease in the number of days between seasonal peaks was observed. If the maximum shifted to the beginning of August, the number of days between peaks increased. The ratio of cloud-to-ground (CG) lightning strokes and the ratio of negative CG strokes was slightly decreasing by 2015 in the central part of Yakutia.

Temperature Distribution in a Slab During Hot Rolling

1988 ◽  
Vol 110 (1) ◽  
pp. 17-21 ◽  
Author(s):  
A. N. Karagiozis ◽  
J. G. Lenard
Keyword(s):  
Temperature Distribution ◽  
Hot Rolling ◽  
Initial Temperature ◽  
Rolling Reduction ◽  
Steel Slab ◽  
Different Parts

The dependence of the temperature distribution during hot rolling of a steel slab on the speed of rolling, reduction and initial temperature is investigated. It is observed that while the center of the slab cools, the surface loses heat at a much higher rate following which significant reheating occurs. Because of that different parts of the slab receive significantly different thermal-mechanical treatments, possibly resulting in a nonhomogeneous product.

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