RU2557380C1 - Method of rolling of strips in vertical rolls of strip mill - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method includes crimping of strip in vertical rolls after passes in horizontal rolls. Rolling in vertical rolls of a strip mill is performed at hot and cold rolling with relative crimping the limit size of which depends on the ratio of strip thickness to width h_i/b_i after i-th pass in horizontal rolls and the module of elasticity of the material of strip E for wide dimensional and branded range of roll stock.

EFFECT: reduction of variability of strip width without violation of their stability when rolling.

Description

Technical field

The invention relates to the field of sheet rolling production and can be used for hot and cold rolling of metal strips with compression of their side edges in the vertical rolls of sheet rolling units to reduce the width of the finished product with a ratio of thickness and width of the roll h / b less than 0.08.

State of the art

A known method of hot rolling of strips, which includes sequential compression in horizontal and vertical rolls of a strip mill [Rolling thick sheets / Polukhin PI, Klimenko VM, Polukhin VP and others. - M .: Metallurgy, 1984. - S. 70-71].

A method for hot rolling strips of copper and its alloys, adopted by the applicant for the closest analogue, is also known, including stripping a strip in vertical rolls of a reversing strip mill after passes in horizontal rolls [Shatalov R.L., Karpov S.A. Improving the longitudinal stability of the roll during reverse hot rolling of strips on a universal mill // Transactions of the Sixth Congress of Rollers. T. 1 (Lipetsk, October 18-21, 2005). - M.: Association of distributors. - 2005. - S. 99-10].

The disadvantages of the known methods are as follows.

Compression of the rolled strip in the vertical rolls of the mill with an force less than its critical value, under the condition of maintaining the longitudinal stability of the roll, is impossible in the absence of a meter of this force. Rolling with an absolute lateral compression less than the calculated critical value is possible only for a narrowly limited size-grade range of rolled products.

These disadvantages do not allow rolling strips of a wide size-grade assortment in the vertical rolls of a strip mill without violating their stability. In case of unreasonably large lateral reductions, the longitudinal stability of the rolled strip may be lost, longitudinal bending and ejection of the roll from the vertical rolls of the mill can occur.

In addition, in the vertical rolls, only the strip is hot rolled.

Description of the invention

The technical task of this invention is to reduce the wide range of finished products of a wide size-grade assortment.

The technical result of the invention is achieved by a reasonable choice of the relative compression of the lateral edges of the strip, eliminating the violation of the longitudinal stability of the roll.

Features

The method differs from the known one in that the strip rolling in vertical rolls of a strip mill is performed during hot and cold rolling with relative compression, the limiting value of which depends on the ratio of thickness to strip width h _i / b _i after the i-th pass in horizontal rolls and the elastic modulus strip material E for a wider size-grade range of rolled products: h / b = 0.006-0.072 and E = (7.42-12.71) · 10 ⁴ MPa.

The method works as follows.

, %, где b_i, b_i+1 - соответственно ширина полосы на входе и выходе из вертикальных валков.After passes in horizontal rolls, a strip of thickness h _{i is} rolled in vertical rolls of a strip mill with relative compression $${\epsilon }_b=\frac{b_i-b_{i-\mathrm{one}}}{b_i}\cdot \mathrm{one\; hundred}$$

,%, where b _i , b _{i + 1} - respectively, the strip width at the entrance and exit of the vertical rolls.

In this case, the maximum permissible relative lateral compression with a probability of P = 99% is determined by the ratio:

ε _b = (5.5 ± 0.34) · 10 ^-4 · (h _i / b _i ) · E,%.

This rolling method reduces the width of the produced strips without violating their stability.

The method can be implemented on an industrial unit, for example, a continuous broadband mill 2000, when rolling in the last two or three universal stands of its draft group.

Implementation example.

Busbar rolling from a billet of copper-nickel alloy ISC 15-20 (soft condition) with a cross section of 1.15 × 98.0 mm in horizontal rolls of a non-reversible mill DUO 260 × 400 is performed with a relative compression ε _h = 1-9%. Vertical rollers are located on the inlet side of the mill for crimping the side edges of the workpiece.

The ratio of the thickness and width of the workpiece h _i / b _i = 1.15 / 98 = 0.012, the elastic modulus of the strip material is E = 11.33 · 10 ⁴ MPa. Then, according to the given ratio, the calculated value of the maximum allowable relative compression of the workpiece in vertical rollers will be:

ε _b = 5.5-10 ^-4 · 0.012 · 11.33 · 10 ⁴ = 0.75%.

Experimentally, using a roller strip deflection meter, a violation of the longitudinal stability of this assortment was found with a relative lateral compression ε _b ≥ 0.80%.

Due to the rolling of the strips in the vertical rolls of the strip mill with the preservation of their longitudinal stability by the proposed method, a decrease in the width width and an increase in the yield for rolling redistribution is achieved.

Claims (1)

A method of rolling metal strips in rolls of a strip mill, including compressing the strip during passes in horizontal rolls and subsequent compression in the vertical rolls of a strip mill, characterized in that at the entrance to the vertical rolls, the ratio of the strip thickness h _i to its width b _i is h _i / b _i = 0.006-0.072, and the compression in the vertical rolls is carried out with the maximum allowable relative lateral compression ε _b determined by the ratio:
ε _b = 5.5 · 10 ^-4 · (h _i / b _i ) · E,%,
where i is the number of the passage in the horizontal rolls before crimping the strip in the vertical rolls,
E = (7.42-12.71) · 10 ⁴ is the elastic modulus of the strip material, MPa.