JPS597401A - Blooming roll having dissimilar upper and lower diameters - Google Patents

Abstract

PURPOSE:To eliminate the restriction in the size of a steel ingot owing to roll kiss and to reduce the unit of the rolls by making the rolling down caliber of an upper roll larger in diameter than that of a lower roll. CONSTITUTION:Since only the lower roll is restricted by a pass line, the lower roll 6 is required to have a roll shape basing on a deep bottom caliber, but the thickness rolling down caliber 2 of an upper roll 5 is made shallow or the roll is made flat. The roll 5 is further made into a projecting shape to make the diameters of the rolls 5, 6 different so that the restriction in the size of the ingot owing to roll kiss is eliminated. In the stage of discarding the rolls, the large diameter roll side having different diameters are machined to the small diameter roll having different diameters, whereby the unit of the rolls is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a high-lift mill to reduce the number of milliseconds in one process during the width reduction pass. The present invention relates to a roll having a deep bottom caliber capable of making a large width reduction of oom+n or more.

In other words, by making the caliber TF10-roll for thickness reduction different in diameter, the restrictions on the billet size due to punching and roll kissing are eliminated, and when the roll is discarded, 1llllll of large diameter rolls of different diameters are used.
The invention relates to a slag roll that can reduce the unit consumption of white roll by turning and swinging it as small rolls with different diameters.

Since the rolling in the blooming process requires a relatively small rolling cap and rolling reduction in the next rolling process, a large width reduction amount is required in the blooming process. Therefore, for billet sizes that require a large amount of width reduction, the dog bone that is squeezed out from the roll flange during width reduction is rubbed out at the outer periphery of the flange, resulting in fold-like flaws on the surface of the billet. Reborn. Since these fold-like defects appear as serious dent-like defects on the surface of the product in the next rolling process, complete removal using a cold piece was required.

However, in recent years, the shift between the blooming process and the subsequent rolling process is rapidly progressing, and the above-mentioned surface flaws must be prevented or removed beforehand in the blooming process. For this reason, as a conventional method to prevent the above-mentioned surface defects from occurring during blooming in a high-lift mill, width reduction is performed again after the dog bones are eliminated by a horizontal pass before the roll caliber and dog bones become overfilled during width reduction. He was using an unnatural pressure sword technique. The inventors of the present application have developed a roll caliber that does not generate crease-like flaws even when expanded to the width of the width of the rolled lid during lotus rolling using the blooming method in a high-lift mill. This requires the following effective caliber depth 1 (+t+m) for the desired maximum width reduction amount, and a deeper width reduction caliber is required.

Effective caliber depth t (+IIIJ= o, 04
4 X material width b (+nm) + o, i 35 If the conventional roll is changed to a deep-bottom caliber, other calibers will have to be deep-bottomed to match the caliber for wide reduction, so the distance between the upper and lower roll calibers at the time of roll kissing will be large, making it difficult to roll steel. There will be restrictions on the size of one side. Furthermore, changing from the conventional roll diameter to a deep caliber results in a significant increase in the roll consumption rate as well as a decrease in the roll effective diameter.

The present invention provides a high-lift mill with the following advantages:
When applying a deep-bottom caliber that can obtain the desired large width reduction in the L process, there is no restriction on the size of the billet that can be rolled, and the roll material is It is in the chunking roll that aims to suppress the increase in units.

The path line of the blooming roll in a high-lift mill can be explained using FIG. 1 as follows from the energy balance at the neutral point.

ψ==-(-ra2 f2 ψ, neutral point α1, bite angle f, friction angle F=Ptanf: Frictional force Therefore, from the condition of ψ>0, 2f)α+>O), in this range, ψ is in contact It is within the circle and rolling is possible, but f>cl is required when biting occurs.

Here, we will explain the caliber depth of the conventionally used rolls and their relationship with the table roller.
The figure shows a roll with a caliber of normal depth, l is a width reduction caliber, 2 is a thickness reduction caliber, and 3 is a full roller, which is slightly smaller in diameter than the thickness reduction caliber 2ii and flange 4, and is a width reduction caliber. Caliber 1 is Caliber 2
It was common to make the diameter slightly smaller. father roll 5
The diameter of the lower roll 6 was the same or close to it for each caliber. As mentioned above, in performing large width reduction, the present inventors use the width reduction blade IJ bar l as shown in FIG.
It is possible to perform a large width reduction in the order of 200 in one process as a deep bottom.However, in order to ensure that the pass line, that is, the upper surface of table roller 3 and the upper surface of roll caliber 1 or 2, is within a certain distance. If some calibers are deep bottomed, other calibers must also be deep bottomed, and if this is the upper and lower eye diameter, the upper and lower roll caliber spacing will increase during the roll kiss when the 7 ranges of the upper and lower rolls come into contact.・Restrictions on the size of copper pieces due to rolls are a problem.

Therefore, in the present invention, since the only restriction from the pass line is the troll, the lower roll must adopt a roll shape based on the deep bottom caliber. Caliber 2 is shown in Figure 4 (a)
A shallow caliber is used as shown in +, or a flat roll without a caliber is used as shown in Fig. 4(b).

In history, the upper roll is made into a convex roll as shown in Figure 4 (CL), and the upper and lower rolls are made with different diameters to eliminate the restriction on the billet size due to the white roll kiss.In addition, in general,
The amount of wear of the Kyomi rolling caliber is very high, and it is also suitable for rolling loads.
Since this is a dog, the maximum moment and maximum stress will occur in this caliber, and this caliber was the standard for the roll waste diameter. Therefore, if the thickness reduction caliber is made deeper in conjunction with the deepening of the caliber during the width reduction, the roll effective diameter will be reduced and the roll unit consumption will be significantly increased. Therefore, in general, the distance between the roll stand posts of the upper roll is wider than that of the lower roll because the roll goes up and down.

By setting the new upper roll diameter as iiE = 2 roll diameter = ITh discarded roll diameter + 2x (lower roll effective diameter) - By turning the upper roll without discarding the upper and lower roll center when the F roll is discarded. It can be played as a new lower roll.

After purchasing 1 set of roll cents, the purchase of 1n10-le only requires the upper roll Vζ, and the roll consumption rate is halved compared to the conventional purchasing method.

Next, a description will be given of the rotation control of the upper and lower work rolls using rolls of different diameters when a relatively thick phase material is ground during compaction using the roll of the present invention.

By matching the neutral points of the upper and lower rolls of the different diameter rolls, the shape of the billet after blooming is comparable to that of the same diameter rolls with dust. The vertical roll control method for this purpose can be considered as follows.

That is, as shown in Fig. 5, there are points M relative to the center of the upper roll.
``+, work.-7,.Half-sized, one, one, .yowa speed'
e V” + vertical roll interval fhu at neutral point.

Neutral point angle relative to the center of the lower roll Total 02. Bottom roll radius? l-R2+speed of the scraping material at the neutral point kV'+the upper and lower roll spacing at the neutral point is hc, and the circumferential speeds of the upper and lower rolls are V'+- and Vsi, respectively, then v x=Vv cos θI , v4=V4coeθ2
・, --(Set as equation 11. Since each angle can generally be assumed to be a small angle, v u, -T, , cos (u02), V4=
V4 CO8θ2 , , (taken as JI formula. Also, from the condition of constant volume, hzvz=hvvXL,', hz'7zcosθ2=
h + zVucos ('jθ2] 1. (Test 1) In general, the relationship between any roll angle θ in the contact arc between the roll and the material and the roll concave gap at that time is expressed as h, -1 - R1/2 (Ru roll radius) If the neutral point angles with respect to the roll center are θ'u and θ', respectively, the roll interval at each neutral point is '- Therefore, (3) Substituting the formula into formula (2), cosθ1,1--i
Therefore, if the neutral point positions match, 14.0 i
= OXL The force and upper and lower roll circumferential speed ratios are good. In this way, by controlling the peripheral speed of the upper and lower rolls, the neutral point of the upper and lower rolls can be controlled so that the shape of the slab is the same as that of rolls of the same diameter. Furthermore, the roll consumption rate due to the deepening of the caliber increases by more than 10.0% compared to the conventional roll consumption rate in the case of rolls that do not take countermeasures against the deepening of the caliber. However, by applying the blooming roll according to the present invention, we were able to suppress the increase in unit consumption to less than 15%, as shown in FIG. or,
By applying the present invention, it is possible to eliminate the occurrence of folded soft sails in the straight rolling process 8 of a high-lit mill, and furthermore, it is possible to minimize the increase in roll consumption due to the deepening of the caliber. This means that the effect on the item, the saving ray, the ruki, and the saving monument.

[Brief explanation of drawings]

Figure 1 is a diagram explaining the relationship between the biting angle and the neutral point・i2
The figure is a diagram of a roll with a conventionally used normal depth caliber, Figure 3 is a diagram of a roll with a deep caliber with upward and downward diameters, and Figure 4 (a), (bl, tcI are from the book). An explanatory diagram of the invention, Fig. 5 is an explanatory diagram of roll circumferential speed control when using a soil/lower diameter lower row nozzle, and Fig. 6 is a diagram showing the reduction in roll consumption rate according to the present invention. 0 1 ・・Width reduction caliber 2 ・Thickness pressure caliber 3・°−・ ・Tiful roller 4・・・Flan 1 5 ・・・・Upper roll b ・・・・ Troll Applicant: Nippon Seimei Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 4 (a) (b) Figure 5
figure

Claims (1)

[Claims] A pair of upper and lower blooming rolls having a plurality of calibers, wherein the diameter of the upper roll is larger than that of the lower roll of the lower caliber.