SU1225631A1 - Rolling mill roll set - Google Patents

Description

The invention relates to rolling production and can be used in the production of sheets,

The purpose of the invention is to improve the quality of the finished strips and stabilize the rolling process.

FIG. 1 shows a set of work rolls for a sheet rolling stand, which is general in FIG. 2 and 3 are curves of variations in the roughness of the working surface along the length of the roll barrels of the roller set.

The set consists of the upper 1 and lower 2 work rolls, the length of the barrels of which are roughened varying in sinusoidal law, while the minimum roughness of the working surface of the roll barrels R is in the range of 0.4-0.8 µm, and the maximum value - R is 2. - 1.0 mm. The extremes of roughness of the same sign on the barrel of one roll are offset relative to the corresponding extremes on the barrel of another roll along their length by half the period, which is within 0.33-0.002 of the length of the roll barrel.

The minimum value of roughness R is predetermined by the possibilities of the grinding operation, and the reduction of this value by polishing the roll barrels is impractical due to the high cost

An increase in roughness of more than 1 mm is limited by the technical possibilities of the known methods of applying roughness and can negatively affect the quality of the rolled surface.

An increase in R of more than 0.8 microns and a decrease in R of less than 2 microns reduce the roughness control range along the roll barrel forming, thereby losing the positive effect of using rolls with different roughness, the asymmetrical rolling process approaches a symmetrical one. Therefore, the maximum roughness value should exceed the minimum 2.5-2500 times.

An increase in the period of sinusoids of more than 0.33 barrel length is unacceptable, since with the number of sections with different roughness equal to two, there appears a significant integral asymmetry of the rolling process.

Since changing the roughness is applied discretely, for example

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when electrosparking with discs whose thickness cannot be less than 0.5-1.0 mm, it is impractical to reduce the period of sinusoids less than 10 mm to ensure a relatively smooth change of the integral roughness along the roll barrel forming; Taking into account that the maximum length of the roll barrel of existing products | 1x mills is 5000 mm, the minimum period in relative units must be equal to or greater than 0.002 barrel length.

The proposed set of rolls can be made by grinding the surface of the barrel and the subsequent electro-sharp processing. The roughness change is made after each turn of the roll by adjusting the electrical process parameters that affect the value of the roughness parameter (current or voltage during sparking).

The set of rolls works in the following way.

Rolls capture the strip fed to them. After the metal has filled the deformation zone, the strip leaves the rolls without deviating from the rolling level. This facilitates filling the strip into subsequent stands or onto a winder.

The stability of the rolling level, regardless of the process asymmetry, is due to the following reasons. In cross sections perpendicular to the roll axes, the roughness of paired rolls is usually asymmetric. Due to the asymmetry of the roughness in each section, the strip tends to be bent towards one of the rolls. In the adjacent section, where the asymmetry changes sign to the opposite, the strip tends to be bent toward the other roll. Since the average roughness of paired rolls are equal or differ by no more than 10%, the strip is not bent. However, with this, due to the asymmetry of the process, the pressure of the metal on the rolls decreases at each of the sections, which allows rolling at a lower cost.

When executing a strip of rolls, on KOTOpbDC. the roughness of the sinusoidal change, on the metal, the appearance of longitudinal strips is possible, the roughness of which varies adequately the roughness of the rolls In some

In such cases, the presence of such strips on ready-made steel may be useful, for example, when it is necessary to provide a stretch-width-differentiated sheet (creating a quasi-reinforced stamped part) or a differentiated thickness of zinc or other type of coating during stamping.

In those cases when the appearance of strips with different roughness is undesirable, their absence is ensured by the fact that a set of rolls is installed in the last stand, the roughness of which also varies sinusoidally, but opposite in phase (along the length of the barrel).

The strip deformation is more than 50% after rolling on rolls with sinusoidally varying roughness when rolls with different roughness are installed in the 1st stand of a multi-mill mill. After deformation in subsequent cages and strip training, the difference in roughness is practically absent (0.1-0.15 Ra) o

Example Making rolls kit

Variable roughness along the roll barrel is produced by electric-spark machining of polished shafts. Processing modes: electrode feed 1 mm / rev; working current 70 AJ roll rotation speed 10 rpm

Controlling the roughness level is done by adjusting the voltage on the electrode. The voltage is varied from. About up to 30 V at the sinusoidal angle of the 5 points beam Figure 2

Well, when moving the electrode along the roll barrel.

The electrodes are made in the form of discs with a diameter of 150 mm and a thickness of 1 mm from st Eli Y8. The period of change of the roughness level is T 0.006 L. Extreme roughness roughness R 0.4 µm (polished surface); R 10 µm-25. Using a set of rolls with the specified roughness distribution ensures reliable gripping of the strip during the reduction of 20-40%,. prevent the strip to be rolled along the roll axis and ensure energy consumption is reduced by an average of 8%.

When making a roll with a roughness change period of less than 0.002 barrel length, the surface quality of the roll barrel is unsatisfactory due to the banding caused by a discrete change in roughness by a significant amount with a single roughness stripe pitch equal to 1 mm (equal to the thickness of the electrode for electric spark treatment).

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For 1700 hot rolling rolls made for a mill with varying working surface roughness with a period of varying the roughness level of 0.005 barrel length, the minimum roughness level is 0.8 microns, the maximum is 0.5 mm, R VR 1250. Operation These rolls showed improved rolling strip conditions, reduced slippage and slippage.

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Editor V. Petrash

Order 2019/7 Circulation 518 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow9 Zh-35, Raushsk na.b., d. 4/5

Production and Polishing Enterprise Uzhgorod9, Proektna St., 4

Compiled by Y.Lov mov Tehred G. Garber

Proofreader A.Zimokosov

Claims (2)

1. SET OF WORKING ROLLS, I mainly sheet rolling stands, the barrels of which have a wave-like roughness varying parallel to their generators, which is different from the fact that, in order to improve the quality of the finished strips and stabilize the rolling process, the roughness on the barrels of both rolls is made according to sinusoids with equal extrema and period, moreover, the extrema of the same sign on the barrel of one roll are offset relative to the corresponding extremes of roughness along the length of the barrel of the other roll by half the period. 2. The kit according to p. ^ Characterized in that the largest value of the roughness of the barrels exceeds the smallest by 2.5-2500 times, and the period of the sinusoid is 0.002-0.33 the length of the roll barrel. Figure 1 SU, 1225631