SU1253682A1 - Method of rolling a sheet in trio mill - Google Patents

Description

The invention relates to the processing of metals by pressure, in particular the production of rolled products on sheet mills of the Lauta Trio.

The aim of the invention is to improve the quality of the sheet durability of the rolls by equalizing their wear.

The drawing shows the arrangement of the rolls for the production of a sheet in the cage of the Lauta trio.

Arrow A shows the directions of the first and last pass and indicates that metal deformation begins and ends between the lower 1 and middle 2 rolls. With simultaneous material of the outermost vapas, the difference in hardness of the lower and upper 3 rolls is 10-15% of the hardness value of the upper roll. With the same hardness of both extreme rolls, the lower roll 1 is made of the most doped nickel-chromium cast iron with a carbite-base structure, and the upper roll is made of undoped bleached cast-iron with a cement-pearlite structure.

Example i, At the mill 2350, when rolling sheets into the cages of the Lauta trio, extreme rolls of the same material are used — cast-iron bleached rolls of the LP design. New rolls have a run-up of 58-65 units. Shore, depending on carbon content. As the rolls overflow, their hardness decreases to 53-60 units. by Shore. Therefore, there is always a roll park with a hardness of 53-65 units in the mill. Complete extreme rolls with a difference in hardness. The hardness of the roll barrels is measured, they are completed with the specified difference (for example, .59 and 65 units), after which the hard roll of 65 units is placed in the lower cage, as the rolling mill adopted the first and last pass between the lower and middle rolls. Roll with a hardness of 59 units. overwhelm the top. Rolling lead by the technology. In the future, when regrinding, they control the hardness of the rolls and, as necessary, re-sets E), they are wound.

EXAMPLE 2: In the mill 2350, cast iron pulp rolls of the performance LI are used in the cage of the Lauta trio.

with a hardness of 58-65 units. and cast-iron double-layer rolls with chromium and nickel alloying of the LPHND version with a barrel hardness of 62-69 units. by Shore.

It can be seen that the range of hardness 62- / 65 units. refers to rolls of both versions. In the presence of rolls with the same hardness complete extreme rolls so that

in the most loaded working position bilayer LPHNd rolls, and in less loaded position - iron bleached PL, as a result of the high degree legiro5 Vani bleached layer LPHNd rolls become more durable carboxy bidobeynitnuyu structure with microscopic vklkzcheni mi graphite as compared with cement-pearlite structure ° round of bleached rolls of LP. Since the surface of a harder or doped roll is more resistant to wear, the intensity and amount of wear of the end rolls during operation in the mill is evened out. This reduces sheet thickness, improves the surface quality of the sheet to be rolled, because the most wear-resistant rollers are involved in the finishing pass and less often subjected to indentations, jolts and cuts, increase the durability of the rolls and the mill productivity by extending the inter-transfer times of the edges of these rolls.

The table presents the test results roll knot.

As can be seen from the table, with the extreme hardness of the extreme rolls (test 1), the wear rate of the lower roll is 2.06 times the wear of the upper roll. The rolls rolled 9328 tons of sheet, after which the transshipment and re-grinding of both extreme rolls were performed due to the large wear of the most loaded lower roll. Although the upper roll was still able to work under the conditions of wear, it was also subjected to a re-point and in order to achieve the same diameter of the extreme rolls when preparing them for the next campaign (filling) from the upper roll with regrinding. which reduces its resistance,.

With the increase in the difference in hardness between the lower and upper rolls to

to drive both rolls after rolling already on the order. II thousand tons metal, which increases the interchange 10% difference in the amount of wear of the rolls decreases (experiments 2-4J. If the difference in hardness is more than -15% (experiment 6), the resultant time of the rolls is reversed and the prostate is reduced — the upper roll wear exceeds 5 of that mill for transshipment. When over-loaded, the lower shaft-point of these rolls is removed, i.e., the target is not of the same magnitude, but since this removal is being rolled, more metal is rolled.

The best results were obtained by the overall resistance of the rolls for service.

when picking the outermost rolls, the bu increases.

the difference in hardness is 10-15% (experience 4-As a result of the implementation of the proposal, 5). It can be seen that the intensity and magnitude of my roller unit in the stand of trio wear of the upper and lower shaft of the mill is expected to decrease the alignments and the permissible movement of the rolls by 25%, which allows them to produce 4 rolls in year.

to drive both rolls after rolling already on the order. II thousand tons metal, which increases the time between rolls rolls and reduces the simple mill for transshipment. At regrinding of these rolls, the same size was produced, but since at this removal more metal was rolled.

Claims (1)

METHOD FOR SHEET ROLLING IN TRIO LAUTH MILLS, including metal compression between two extreme rolls having different hardness, with even and odd passages, characterized in that, with a chain for improving sheet quality and roll resistance by equalizing their wear, metal compression in an odd pass produced between the extreme rolls, one of which has a hardness 10-15% greater than the hardness of the other. u sl s * e QO No.