scholarly journals Theoretical analysis of formation of automobile sheet roughness during temper rolling in shot-blasted rolls

2019 ◽  
Vol 62 (8) ◽  
pp. 600-605 ◽  
Author(s):  
N. N. Ogarkov ◽  
E. Yu. Zvyagina ◽  
R. R. Ismagilov
Keyword(s):  
Quantitative Estimation ◽  
Metal Flow ◽  
Spherical Shape ◽  
Mechanical Action ◽  
Uniform Structure ◽  
Rolled Strip ◽  
Temper Rolling ◽  
Superposition Method ◽  
Sharp Edges ◽  
Roll Roughness

The methods of microgeometry formation for the surface of temper mills rolls are presented providing the required roughness of the cold rolled strip. It was established that with the electroerosion processing a more uniform structure is formed on the roll surface with a smoothly changing microrelief, compared with the mechanical action of the abrasive. The most effective abrasive for the microrelief formation on the rolls surface is cast and split steel shot. The process of interaction predominantly occurs with round-shaped shot, since the sharp edges of the split shot also become blunt during it. In the present work, the microdepression of the roll is approximated by a spherical shape. A model of roll roughness transfer to the strip was developed taking into account the type of roll processing and tempering conditions, which makes it possible to evaluate the degree of filling of a single microdepression relief at known pressures at contact of the strip with the roller, friction coefficient, roll roughness parameters and tempering modes. A quantitative estimation of reproduction of the roll roughness on the trained strip was obtained, characterized by the roughness ratio, which is the ratio of the depth of the metal flow into the strip microdepression to the depth of the roll spherical microdepression. Determination of the dimensionless pressure required for flowing a deformable metal into it was performed using the superposition method for meridian sections in two mutually perpendicular planes. The reproduction dependencies of the micro-geometry of a temper mill roll on a rolled strip on the shot size, tension, and the height parameter of roughness are presented during the tempering of stripes with various thickness, which can be used to simulate the transfer of the roll micro-relief to the rolled strip.

An Approximate Method of Estimating the Yield of a Strip Under Tension Cut by Serrated Surfaces on Opposite Faces

2003 ◽  
Vol 125 (2) ◽  
pp. 170-175
Author(s):  
Jingyu Shi ◽  
D. L. S. McElwain ◽  
S. A. Domanti
Keyword(s):  
Critical Angle ◽  
Critical Pressure ◽  
Control Process ◽  
Rolling Process ◽  
Rolled Strip ◽  
Temper Rolling ◽  
Lateral Tension ◽  
Line Theory ◽  
On Line ◽  
Extensive Computation

In view of the well-known disparity between predictions from temper rolling models and measured values from rolling mills, there is a need to obtain a better understanding of the effect of roll asperities on the yielding characteristics of the rolled strip. This paper models a roll with asperities as a rigid body with a regular serrated surface and the rolling process as an indentation, and uses the plane strain model and slip-line theory to determine the critical pressure that is required to yield the strip throughout the thickness beneath the tips of the asperities. The strip is also under lateral tension at both ends. The emphasis of the paper is the effect of the lateral tension and the thickness of the strip on the critical pressure. For the case when the indenting surface has sharp teeth, the critical pressure can be found in close form. For the case when the indenting surface has blunt teeth, a robust approximate scheme for estimation of the critical values that does not require extensive computation is given and this scheme can be used in an on-line control process. It is found that when the tooth angle is smaller than a critical angle, the sharper the tooth, the lower the average critical pressure needed to make the strip yield. When the tooth angle is larger than the critical angle, then the blunter the tooth, the lower the pressure that is needed. The effect of the asperities is to reduce the critical pressure and it is found that this effect is more pronounced for thin strips than for thick strips. The lateral tension reduces the critical pressure further. These findings give some implications for the rolling of metal sheets.

scholarly journals Estimation of depth and degree of mill roll surface hardening during grit texturing

2020 ◽  
Vol 63 (9) ◽  
pp. 735-741
Author(s):  
E. Yu. Zvyagina ◽  
N. N. Ogarkov ◽  
M. A. Polyakova ◽  
M. D. Sukhova
Keyword(s):  
Surface Layer ◽  
Layer Structure ◽  
Surface Hardness ◽  
Spherical Shape ◽  
Hardened Layer ◽  
Optical Microscope ◽  
Rolled Strip ◽  
Textured Surface ◽  
Roll Surface ◽  
Deformation Degree

The paper presents shot blasting (SB) as the most common method of arrangement of temper mills rolls surface microgeometry, providing required roughness of the cold-rolled strip. The surface riffing studies were carried out at the Willibrator industrial unit; metallographic studies were performed using MEIJI 2700 optical microscope and JSM-6490LV scanning electron microscope. Refinement of the surface layer structure during interaction of the roll material with the grit was revealed. In the work the lower bound method, one of the methods of plasticity theory, is used for theoretical analysis of the SB process. To make computations easier, the roll microcave is approximated to spherical shape. Quantitative estimates of deformation degree and the depth of hardened layer were determined by speed of the grit and hardness of the roll surface. The depth of hardened layer is obtained by the size of used grit, and to a lesser extent, by the speed of grit impact on the roll surface and textured surface hardness. It has been searched out in literature that increase in hardness by one unit leads in average to 3 % increase in resistance. Thus, SB application allows reduction of time of rolls rehandling of temper mills by 6.0 – 10.5 %, depending on application modes of rolls riffing with grit. Analysis of microstructure have shown that increase in hardness of the surface layer is a consequence of refinement of its structure in process of interaction with the grit. It has been revealed that increase in hardness of the surface layer leads to an increase in its wear resistance and fatigue strength. The authors of the work have found that at speed of 60 m/s the hardness increases by 3.5 units.

Macrostructure and microphysics of Saturn's E-ring

1984 ◽  
Vol 75 ◽  
pp. 607-613 ◽  
Author(s):  
Kevin D. Pang ◽  
Charles C. Voge ◽  
Jack W. Rhoads
Keyword(s):  
Size Distribution ◽  
Spherical Shape ◽  
Mie Scattering ◽  
Narrow Size Distribution ◽  
Electrostatic Levitation ◽  
Volcanic Origin ◽  
Micron Diameter

Abstract.All observed optical and infrared properties of Saturn's E-ring can be explained in terms of Mie scattering by a narrow size distribution of ice spheres of 2 - 2.5 micron diameter. The spherical shape of the ring particles and their narrow size distribution imply a molten (possibly volcanic) origin on Enceladus. The E-ring consists of many layers, possibly stratified by electrostatic levitation.

On the Shape of Field-Ion Emitters

1976 ◽  
Vol 34 ◽  
pp. 520-521
Author(s):  
H.C. Eaton ◽  
B.N. Ranganathan ◽  
T.W. Burwinkle ◽  
R. J. Bayuzick ◽  
J.J. Hren
Keyword(s):  
Grain Boundary ◽  
Spherical Shape ◽  
Theoretical Strength ◽  
Evaporation Process ◽  
Field Evaporation ◽  
Geometric Information ◽  
Field Ion Microscopy ◽  
Considerable Error ◽  
True Shape ◽  
Ion Microscopy

The shape of the emitter is of cardinal importance to field-ion microscopy. First, the field evaporation process itself is closely related to the initial tip shape. Secondly, the imaging stress, which is near the theoretical strength of the material and intrinsic to the imaging process, cannot be characterized without knowledge of the emitter shape. Finally, the problem of obtaining quantitative geometric information from the micrograph cannot be solved without knowing the shape. Previously published grain-boundary topographies were obtained employing an assumption of a spherical shape (1). The present investigation shows that the true shape deviates as much as 100 Å from sphericity and boundary reconstructions contain considerable error as a result.Our present procedures for obtaining tip shape may be summarized as follows. An empirical projection, D=f(θ), is obtained by digitizing the positions of poles on a field-ion micrograph.

Investigation on the control of multiphase flow behavior in a continuous casting tundish during ladle change

2020 ◽  
Vol 117 (6) ◽  
pp. 619
Author(s):  
Rui Xu ◽  
Haitao Ling ◽  
Haijun Wang ◽  
Lizhong Chang ◽  
Shengtao Qiu
Keyword(s):  
Multiphase Flow ◽  
Flow Behavior ◽  
Rolled Strip ◽  
Impact Zone ◽  
Steel Cleanliness ◽  
Carry Over ◽  
Slag Carry Over ◽  
Hot Rolled ◽  
Turbulence Inhibitor ◽  
The Impact

The transient multiphase flow behavior in a single-strand tundish during ladle change was studied using physical modeling. The water and silicon oil were employed to simulate the liquid steel and slag. The effect of the turbulence inhibitor on the slag entrainment and the steel exposure during ladle change were evaluated and discussed. The effect of the slag carry-over on the water-oil-air flow was also analyzed. For the original tundish, the top oil phase in the impact zone was continuously dragged into the tundish bath and opened during ladle change, forming an emulsification phenomenon. By decreasing the liquid velocities in the upper part of the impact zone, the turbulence inhibitor decreased considerably the amount of entrained slag and the steel exposure during ladle change, thereby eliminating the emulsification phenomenon. Furthermore, the use of the TI-2 effectively lowered the effect of the slag carry-over on the steel cleanliness by controlling the movement of slag droplets. The results from industrial trials indicated that the application of the TI-2 reduced considerably the number of linear inclusions caused by ladle change in hot-rolled strip coils.

Hot-rolled strip re-reddening temperature changing law for late ultra fast-cooling in a CSP line

2015 ◽  
Vol 112 (3) ◽  
pp. 305 ◽  
Author(s):  
Lian-yun Jiang ◽  
Guo Yuan ◽  
Jian-hui Shi ◽  
Yue Xue ◽  
Di Wu ◽  
...  
Keyword(s):  
Rolled Strip ◽  
Hot Rolled Strip ◽  
Ultra Fast Cooling ◽  
Fast Cooling ◽  
Hot Rolled

Plasma Fibrin Stabilising Factor (F. S. F.) Activity in Normal Subjects and Patients with Chronic Liver Disease

1969 ◽  
Vol 21 (01) ◽  
pp. 134-143 ◽  
Author(s):  
W. D Walls ◽  
M. S Losowsky
Keyword(s):  
Liver Disease ◽  
Chronic Liver Disease ◽  
Clinical Improvement ◽  
Quantitative Estimation ◽  
Kinetic Method ◽  
Normal Subjects ◽  
Chronic Liver ◽  
Clinical Severity ◽  
Plasma Fibrinogen ◽  
Normal Range

SummaryA kinetic method for the quantitative estimation of plasma F.S.F. activity is described and discussed.This method was applied to normal subjects and to patients with chronic liver disease. The plasma F.S.F. activity was uninfluenced by either sex or age, and the normal range has been defined.A significant decrease in plasma F.S.F. activity was observed in patients with chronic liver disease. Subnormal levels of activity were found in 25% of such patients but were unrelated to episodes of abnormal haemorrhage. Plasma F.S.F. activity tended to be lower in patients with disease of greater clinical severity. In 2 patients showing clinical improvement there was an increase in plasma F. S. F. activity.It was confirmed that plasma fibrinogen levels increase with age.

Study of the process of forming a hole for a thread at manufacturing a high nut

2020 ◽  
Vol 76 (8) ◽  
pp. 841-846
Author(s):  
I. G. Shubin ◽  
A. A. Kurkin
Keyword(s):  
Metal Flow ◽  
Nonlinear Dependence ◽  
Geometrical Parameters ◽  
Relative Height ◽  
Forming Process ◽  
Normal Height ◽  
Accuracy Class ◽  
Limit Values ◽  
Program Complex ◽  
Class B

During manufacturing nuts of increased height, a problem of obtaining correct cylindrical form of the hole for thread and overall geometrical parameters arises. To solve the problem it is necessary to know regularity of the blank forming process. Results of the study of a technological process of high hexahedral nuts forming presented. The nuts were M18 of 22 mm height, M16 of 19 mm height and M12 of normal height 10 mm according to GOST 5915–70, accuracy class B, steel grade 10 according to GOST 10702–78. The volumetric stamping was accomplished at the five-position automatic presses of АА1822 type. It was determined, that unevenness of the metal flow in the process of plastic deformation of blanks of increased height nuts was caused by different stress conditions by their sections. To simulate the mode of deformation, the program complex QForm-3D was chosen. The complex ensured to forecast with necessary accuracy the metal flow in a blank, as well as to define the deformation force and arising stress in the working instrument. The simulation showed the presence of regularity between preliminary formed buffle and deviation of dimensions and form of a blank wall after its finishing piercing, which can be expressed by a nonlinear dependence. The limit values of the relative height of the buffle С/D = 0.56–0.588 defined, exceeding which will result in rejection of the finished product. Accounting the limit values of the relative height of the buffle will enable to correct a mode of technological operations and technological instruments at stamping of high hexahedral nuts.

Social development of modern Russia: trends, risks, prospects

2018 ◽  
pp. 76-89
Author(s):  
E. M. Avraamova ◽  
V. N. Titov
Keyword(s):  
Middle Class ◽  
Social Development ◽  
Social Structure ◽  
Structure Formation ◽  
Resource Availability ◽  
Social Dynamics ◽  
Quantitative Estimation ◽  
Resource Potential ◽  
Institutional Conditions ◽  
Resource Characteristics

The analysis of present-time directions in the study of social development has allowed to identify the resource approach as the most productive one which enables to assess social dynamics through the range of resource characteristics of different population groups and abilities of the relevant groups to apply development resources in the current economic and institutional conditions. Basing on the sociological survey conducted by ISAP RANEPA, the quantitative estimation of material and social recourses of the population has been made; integral values of the resource potential have been calculated as well. The issues of social structure formation are analyzed through the aspect of resource availability; the barriers of Russian middle-class enlargement are defined.

QUANTITATIVE ESTIMATION OF URINARY PREGNANETRIOL, PREGNANETRIOLONE, TETRAHYDRO S AND Δ5-PREGNENETRIOL IN THE INVESTIGATION OF ADRENOCORTICAL FUNCTION

1969 ◽  
Vol 60 (4) ◽  
pp. 657-668 ◽  
Author(s):  
Frances J. Thomas ◽  
A. W. Steinbeck
Keyword(s):  
Congenital Adrenal Hyperplasia ◽  
Cushing’S Syndrome ◽  
Adrenocortical Carcinoma ◽  
Quantitative Estimation ◽  
Cushing's Syndrome ◽  
Adrenocortical Function ◽  
Adrenal Hyperplasia ◽  
Ectopic Acth ◽  
Modified Method ◽  
Idiopathic Hirsutism

ABSTRACT A modified method for the estimation of urinary pregnanetriol, pregnanetriol, pregnanetriolone, Δ5-pregnenetriol and tetrahydro S was investigated. The steroids, separated by chromatography, were measured quantitatively, tetrahydro S by reaction with blue tetrazolium and the other three as acetaldehydogenic substances. The excretion of these steroids was studied in suspected instances of adrenal and/or ovarian disease. Urinary pregnanetriol and tetrahydro S levels were normal in Cushing's syndrome, secondary adrenocortical carcinoma, the Stein-Leventhal syndrome, idiopathic hirsutism and hypertension. Tetrahydro S was doubtfully elevated in an instance of ectopic ACTH Cushing's syndrome. Pregnanetriol excretion was elevated in untreated cases of congenital adrenal hyperplasia and after treatment in some. Pregnanetriolone was found in all patients with congenital adrenal hyperplasia, including those receiving cortisone. Pregnanetriolone was also detected in Cushing's syndrome, secondary adrenocortical carcinoma, the Stein-Leventhal syndrome, ectopic ACTH Cushing's syndrome and suspected congenital adrenal hyperplasia. Δ5-pregnenetriol was present as a glucuronide in the Stein-Leventhal syndrome and idiopathic hirsutism. The diagnostic implications of these results are discussed.

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