SU1540881A1 - Method of hot rolling of plates - Google Patents

Abstract

The invention relates to the processing of metal by pressure, mainly to the hot rolling of slabs in a rough group of stands of broad-strip mills. The aim of the invention is to save metal by reducing side trimming. The rolling method consists in changing the width of the roll in each universal stand in proportion to the allowable change in width in this stand, crimping the side faces with vertical rolls and providing a predetermined width of the roll into the finishing stand group. 2 tab.

Description

The invention relates to the processing of metals by pressure, in particular to the technology for the production of thick sheets on double-cell reversing hot rolling mills.

The purpose of the invention is to increase productivity.

The method is carried out as follows.

The initial billet is transported to the roughing stand, in which, according to the existing technology, the width is stretched and divided. After dividing the width, the peal rolls over 90 ° tpc, that the longitudinal axis of the slab and the longitudinal axis of the coi mill fall, and if the peal is in front of the cage, the longitudinal rolling is carried out in one pass with the maximum allowable crimping. The thickness of the transfer of roll to the finishing stand should be limited to the specified ratio

h nep (2,1-2,8) Н0п „. In case the roll is behind the draft cage (after dividing the width), the thickness of the transfer of the roll is obtained in two passes. Then the roll is transported to a clean cage and rolled in it to obtain the required sheet thickness.

Example. Comparative rolling according to the known and proposed methods is carried out on a 3600 mill. After heating in a five-tezonic methodical furnace, the slab

4i

About 00 00

ganga is passed to Quarto's roughing stand.

The results of the comparative rolling are presented in Table 1.c.

According to the proposed technology, a sheet of 11x2140 mm is punched from a slab with dimensions 180x1300x x 2100 mm.

Source slab transported to the roughing stand | in which, according to JQ, the current technology extends over. 1 pass and 4 passes width breakdown with a total compression of 88 mm in two steps.

- Based on the ratio, find $ h value

hnep (2.1-2.8) -180-11 (65 + 74) mm.

At reduced costs rolling in the roughing stand to the specified dia, - 20

,- 20

the thickness band is almost the same. Therefore, choose the thickness of the transfer of any of this range of thicknesses.

Next, the roll 180-88 92 mm thick must be rolled in the roughing stand to a value of 65 mm. The position of the roll is determined relative to the roughing stand: after 5 passes, the roll is located behind the stand, therefore, it is rolled in 2 passes. Thus, 30 times, a peal 65 mm thick is transferred to a “finishing stand, in which it is rolled to a thickness of 11 m in 7 passes.

This formula is derived from the following expression

. P opt - Pi ,,, F wnp- tse + p .; d.p (o

where is energy consumed

rolling, MJ / t; 40

ROPT P $ optimal mill productivity and actual, t / h;

C, C - the price of energy and the conditionally-permanent part of the cost of 5 times the transfer of rubles / ton. .

25

with

Jq

$

20

It has been established that the minimum of the functions F is achieved when the ratio of the stretching in the roughing stand to the stretching in the finishing stand is 0.35-0.47. This relationship can be represented as

1 S. l hh-n D7 ()

-TV u u U, JD-U, 4 /, (.Ј)

r2, Pyeg Pl

Analysis of the calculated data showed that with a deviation from the specified range, a sharp decrease in the mill's productivity is observed with a relatively low decrease in electrical costs. Reduced costs increase. The effect of thickness of the transfer of roll on productivity and energy consumption during rolling, as well as the results of the analysis are presented in Table 2.

1 The proposed method improves productivity in the production of sheets of 1.5 million tons per year by 5%.

thirty

Claims (1)

25 claims The method of hot rolling thick plates, mainly on double-sheet reversing mills, including longitudinal and transverse rolling in the roughing stand and final rolling in the finishing stand, characterized in that, in order to improve performance, after cross-rolling, longitudinal rolling is repeated in the roughing stand roll to reach the thickness of the roll defined by the formula (2, l-2.8) N0p „, hnep- thickness of the transfer of roll from rough to finish cage; PL - the thickness of the original billet and the finished sheet, respectively. Costs production sheet st-prot Beam width Longitudinal rolling in a roughing stand Rolling in a finishing stand Protchka Breakdown of width Longitudinal rolling in a roughing stand Rolling in a finishing stand Protruding Breakdown of width Longitudinal rolling in a roughing stand la- Rolling in finishing l i stand Stretching Width breakdown Longitudinal rolling of the roughing stand Rolling in the finishing stand 29 59 37 9.6 24.1 15.5 180 180 55 65 eleven eleven 0.79 0.47 235.4 268.1 43.0 44.8 1.77 0.93 1l .R ABOUT oo OE 75 0.35 270.7 46 ,: 0.92 80 eleven 0.3 219 42.9 1.71 180 180 180 180 80 75 65 60 11 11 11 And Editor G. Gerber Compiled by M. Blatov Tehred L. Oliynyk. Proofreader V.Girn to Order 245 Circulation 412 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Table 42.9 46.1 44.8 44.0 1.71 0.92 0.93 1.42 Subscription