SU1205947A1 - Method of rolling sheets - Google Patents

Description

The invention relates to the processing of metals by pressure, mainly rolling production, and can be used when rolling sheets on sheet mills.

The purpose of the invention is to eliminate the raznosparinnost ends of roll.

When rolling thick sheets, fan-shaped broadening occurs at the front and rear ends of the strip until the formation of hard outer zones, i.e. on the length of the actual deformation center. The length of the actual deformation zone is the sum of the length of the geometric deformation zone (RA) and the length of the non-contact deformation region.

 When limiting extinction and the application of compressive stresses to the lateral edges of the end sections of the strip on a length equal to (1.3-1.5) Pd, the end section of the strip has only one free edge in the longitudinal direction, which, according to the law of least resistance, allows the metal move only in the longitudinal direction.

If limiters are installed at a length of less than 1, DSPd, then the fan-shaped broadening is not completely eliminated and the width of the sheet exceeds the nominal length by part of its length, which leads to a decrease in the yield due to a decrease in the length of the sheet.

I

Length limiters,

more than 1.5U does not affect the output, but it results in the deterioration or breakdown of the limiter lines due to the considerable pressure of the metal on the limiters, which can cause jamming of the bar and an emergency stop of the mill.

In the proposed method, the effect of improving the shape of the sheet in the plan is achieved due to the constraint of fan-like broadening at the ends of the strip.

Example. The cast slabs of steel Zsp with dimensions of Co 250x200x and 2400 mm are rolled into rolls with a diameter of 1000 mm. The rolling speed is VHP 0.2 m / s, the reduction Ah of 40 mm, the temperature of the rocker, the yield strength of the metal at this temperature Sj is 120 MPa.

During rolling, the proposed method is carried out by applying limiters at different distances between the front and rear ends of the slab:, 1,2fA,, ZED, 3, f., 1,5Sd,, 6ЕA.

The time t during which the limiters act on the ends of the slabs is determined as follows: when subjected to limiters, the length of the front or rear end is 1, 212 m

t.l. 1.06 s.

Vnp

15

The effect time on the ends of the slabs is similarly found for other lengths and is given in the table.

As can be seen from the table, as a result of the installation of the limiters and the occurrence of compressive stresses on the front and rear side faces. the ends of the strip decreases the value of the maximum expansion of the ends and increases the elongation of the fit. If at

25 lengths of plots, limiting the widening 1,, ZEA, the amount of expansion at the front end is

32

mm

and in the back - 14 mm, then

five

..

1.3 & d and 1, bc the sheet is obtained by the pr - Q of a mountable shape and the yield is increased by 0.25%. However, with a length of 1.6, the service life of the limiter lines is reduced to 700 hours.

With the lengths of the limiting sections of the broadening of 1, 3SD and 1.4 Un, the yield of the suitable one increases by 0.15 and 0.20%, respectively.

Consequently, the rational values of the lengths of the broadening areas are 1, SED-1, .5 Sd. At smaller values, the yield of a suitable increase is insignificant, and at large values of the length of a section, without an increase in the yield of a reduced, it decreases5

0

five

with the service life of lines, limiters.

The use of the proposed rolling method allows an increase in the yield of a suitable metal due to the production of rectangular sheets, an increase in their length and a decrease in side trimming.

With the elimination of raznosherinnost roll increases the yield of good.

Editor E. Papp

Compiled by M. Blatov

Tehred M. Nador Corrector S.Cherni

Order 8592/8 Circulation: Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Filial ShSh Patent, g, Uzhgorod, st. Project, 4

Claims (1)

METHOD FOR ROLLING SHEETS * including plastic deformation of a workpiece with constrained broadening, characterized in that, in order to eliminate the difference in width of the ends of the roll, constraint is carried out at the length of the end sections equal to (1.3-1.5) 8 ^, and where Cd is the length of the deformation zone R is the radius of the rolls; 4h - absolute compression.