SU1297955A1 - Ingot - Google Patents

Abstract

The invention relates to ferrous metallurgy and can be used for the proc- ing of quiet steel ingots on a bluetooth. The purpose of the invention is to improve the quality of rolled metal and reduce scrap metal. The side faces of the ingot are convex and have a sinusoid shape with an amplitude of 0.02-0.03 facets of the ingot and a period equal to the height of the face of the ingot. The specified shape of the lateral faces of the ingot, the rolling pattern and the deformation mode reduce the unevenness of the broadening over the height of the bar, improve the quality of the blooms surface, reduce the weighting of the end sections of the bar and reduce the waste of metal with an end piece of 2 slit. (L

Description

one

The invention relates to ferrous metallurgy and can be used when rolling quiet steel ingots on a blooming.

The aim of the invention is to improve the quality of rolled metal and reduce metal scrap to trim.

FIG. 1 shows an ingot for rolling a bloom; in fig. 2 - ingot with side edges depending on the technological parameters of rolling

The ingot for rolling blooms includes convex side faces, the shape of which is outlined by a sinusoid with an amplitude of 0.02-0.03 in height H of the ingot and a period equal to the height of the ingot.

This surface shape of the two side faces of the ingot was established as a result of extensive experimental studies of the process of forming during rolling lead samples in a laboratory mill with a roll diameter of 110 mm. The lateral surfaces of specimens imitating ingots on a scale of 1:10 were flattened and figured — in the form of a parabola and a sinusoid in transverse flows of patterns. Samples with different shapes of the side surfaces were rolled according to the deformation modes, providing for the first turning after the second, fourth and other passes.

The most rational form of the side surfaces on the samples before rolling to improve the quality of the side edges is sinusoidal, which is more likely to reduce the non-uniformity of deformation along the height of the side edges,

The shape of the side surfaces of the ingots, determined as a result of the research, is described by the equation

X

de N

f / 2

f

f f / 2 (H-sin (ir / 2 + -), (1)

H

50

the height of the side face of the ingot; the amplitude of the sinusoid; the maximum height of the metal influx in the middle of the side face to compensate for the barrel formation,

X is a variable characterizing the part of the height of the side face (in the middle of the face where f is not, at the ends of the face is H / 2) .uh

The use of the specified form of the facets of the ingot. under the schemes of the wedge of the motif on the tea tov, to perot izvodi on the head to the first depending on the scheme of deforming to dismount

f / ihe.

+1.55

cijM

Rollers and reduction modes, which define a specific value-f, ensure the rational form of the side faces of the rolls after rolling.

Depending on the ingot rolling scheme (two, four or six passes), the total reduction, and the geometric factors of the deformation zone, the value of f is determined by the equation

,, Jl5 (E / h,; -.9,33 (E / h, J,

, 55

Wed Wed

 (2)

0

0

where and h - length and average height

hot spot. The magnitude of the amplitude in the middle of the facet is calculated depending on the geometric parameters of the ingot. From practical experience, it has been found that the convex shape of the side faces of the ingot, made along a sinusoid, allows to reduce the tensile stresses in the contact layers and to reduce the non-uniformity of deformation during rolling on a smooth barrel without turning over for two, four, six or more passes. In addition, this shape of the lateral faces should favorably affect the durability of the molds, which will facilitate the operation of extracting ingots.

The ingot takes into account the peculiarities of shaping the side faces when rolling on a smooth barrel of blooming without grooves. This is especially important in the case when, due to unstable temperature heating, it is necessary to perform six or more passes on a smooth barrel with low cuts to the first folding, Moreover, depending on the total reduction, the rolling pattern, the shape factor of the deformation zone on smooth the barrel before the first canting can predict the amplitude of the sinusoid (bulge) of the side faces of the ingot by the equation

15 (e / h)

-9.33 (E / h, p), p +

the maximum amount of convexity in the middle of the face; total compression in the first passes on a smooth barrel before turning,

/ hj is the shape factor of the deformation zone.

Example. An ingot of quiet steel of rectangular section with dimensions H and B has side faces in the form of sinusoids with an amplitude f / 2 equal to 0.02-0.03 of the height of the face H, with a maximum in the middle and a period T equal to the height of the face N. Indeed, If we consider equation (1), then we can establish that fj varies from about to .-:;

With (middle of the ingot face), with (one quarter of the height of the face) and with (one second height of the face), 0.

Therefore, the change in the convexity of the side faces of the ingot is subject to a sinusoidal law.

According to equation (2), it is possible to calculate the maximum convexity of the side faces of the ingot, depending on the technological parameters of rolling. The essence of this process is explained by a schematic -plotting (Fig. 2) shaping a rectangular ingot of height H and width B with convex edges in the first passes on the palm of a blooming barrel before turning. During the rolling process, in the near-contact layers, especially in zones 1 adjacent to the lateral surface, there are significant tensile stresses that develop from area 2 of maximum, horo broadening. This phenomenon is particularly pronounced in the case of rolling in six or more passes on a smooth barrel without turning.

layers, reduce transverse cross-sectional deformation, non-uniform stress, and avoid the appearance of double barrel formation. This achieves the straightness of the side surfaces and reduces the likelihood of defects. Metal broadening zones 2 45 are localized at the prn-contact surface, in the middle part of the roll, due to the convexity of the faces, compressive stresses appear that prevent double formation.

The convexity of the side faces of the ingot

within (0.02-0.03) N adopted based on the calculation of the design of a thermo-balanced gluhodon layer, as well as to ensure ease of transporting the ingot along the working roller table of the blooming.

The proposed mechanism of plastic metal flow makes it possible over the cross section of the ingot. In the surface layers it is smaller in the center of the roll and increases towards the edges. In the deep layers, on the contrary, it is maximum in the center and. less on the side surfaces. Therefore, the transverse tensile stresses arising in this case are localized in the areas of the lateral surface 3 of the bar (Fig. 2) adjacent to the contact surface 1. On the lateral surface of the bar when rolling on a smooth barrel without turning, it is possible that the metal is discontinuous in case of poor quality and low plasticity of the surface layers. Kantovka after the fourth or sixth pass does not contribute to improving the quality of the surface of the roll. It is advisable after the first two

-five

fO

20

979554

gaps. Rolling with the first turning after the sixth or eighth pass contributes to a significant development of defects and is rarely used in practice. The formation of defects during the rolling of ingots more often occurs on the lateral surfaces that do not come into contact with the rolls, and their appearance depends on the stress-strain state on these surfaces. The condition of the side surface of the roll after rolling on a smooth barrel without turning cans has a significant effect on the formation of wrinkles, wrinkles and sunsets. Therefore, it is very important to choose such a rolling pattern and deformation mode, in order to avoid the formation of defects during the rolling period between the last turning on a smooth barrel and turning around before the task of rolling into a caliber. The more passes between them, the greater the concavity of the side faces of the roll. With the task of such a roll in E (the normal caliber, due to the absence of stretching, the deformable metal layers are directed to the middle of the caliber, forming coarse folds and wrinkles, which are further transformed into sunsets during rolling. The uneven heating of the ingot contributes to this.

The ingot allows for. by performing its side faces along the sinusoid of assigning the amplitude of the sinusoid (you are 35 bumps) depending on the total reduction of dF. and the shape factor of the deformation zone (I / hep) reduce the unevenness of the deformation in contactT

thirty

the ability to control the process of mold, change the metal on the required sections of the roll due to the shape of the side faces of the ingot, the mode of reduction and the parameter of the deformation zone.

Claims (1)

Invention An ingot for rolling blooms containing convex side faces, which is characterized by the fact that, in order to increase the quality of rolled products and reduce metal waste, the side edges of the ingot are outlined with a sinusoid with an amplitude of 0.02 0.03 of the height of the ingot face and a period equal to the height of the face of the ingot ; oag-vmn VNIIPI Order 847/11 Random polygons pr-tie, Uzhgorod, st. Project, 4 Circulation 481 Subscription