SU829231A1 - Method of cooling rolling rolls - Google Patents

Description

I

The invention relates to metallurgy, in particular to rolling production.

A known method of supplying a cooler to the surface of the rolls, in which rotating hollow cylinders with openings for cooling fluid are attached as coolers, has a supply chain through the permeable sheath to the surface of the rolls.

The disadvantage of this method is that the cooling area is a narrow zone of contact between the cooling roller and the roll, which does not provide the required heat removal. In addition, cooling ocjouecT in a small portion of the roll circumference leads to thermal stress arising} in the noBepXHocTiGix roll layers.

There is also known a method for cooling the mill rolls, consisting in a coolant code tangentially to the top of the roll axis.

The disadvantages of this method are low cooling efficiency, since the effective heat removal zone is insignificant (cooling is applied to the direct - forming roll;

this leads to an increase in temperature and its gradient along the roll circumference, which reduces the resistance of the rolls); inefficient use of the chiller, as it contacts the roller only one straight line and is reflected from the surface of the rolls, does not remove heat; a higher density is ooschenno that fiede to the inefficient use of the cooler.

The purpose of the invention is to increase the operational durability of the rolls and to reduce the consumption of the cooler.

The goal is achieved by the fact that the cooler is supplied to the surface of the roll with the angle of its circumference correspondingly. central angle of 80-150 and irrigation density of 50-250 hours.

FIG. 1 shows the proposed scheme for supplying a chill cooler; in fig. 2 is a plot of heat removal from the roll versus cooling angle; in fig. 3 is a graph of heat transfer coefficient versus density of orogiena.

A cooler is supplied to the surface of the roll 1 from the collector 2 so that a zone of efficient cooling of the adenum is provided, which corresponds to the central part H. The irrigation density C, .i is determined by the amount of cooler supplied per unit surface area of the mill roll per unit time.

During the mill operation, the rolls of different stands have different heat loads, which vary during the rolling process depending on the assortment of stripes, rolling speed, etc. Therefore, to ensure the necessary heat removal, it is necessary to change the angle H and the irrigation density q, in the appropriate range. The heat is characterized by a relative temperature Q (Fig. 2), which indicates how average the surface temperature of the roll is close to the temperature of the cooler, i.e. how efficient is cooling

Pelax

.l

where the maximum surface temperature of the roll;

T - average surface temperature

roll;

T (3) d - the temperature of the cooler. From the data in FIG. 2 it follows that an increase in the cooling angle to 150 ° C does not ensure its significant increase. At angles of cooling less than 80 ° C, the heat removal decreases sharply. Thus, the calculation results show that. heat removal effective

in the roll zone corresponding to the central angle of 80-150 C.

Industrial studies of the cooling processes of the rolls were carried out at the 2000 NLMZ mill. The rolls are cooled by

slotted collector installed on the exit side of the metal from the deformation zone. The values of the angles relative to the center line are established by moving the slotted collector around the roll axis and overlapping

slots, and the irrigation density is adjusted by changing the pressure of the cooler. In order to justify the range, t change the effective heat removal zone. The results of the experiment are presented in the table. 1 (orosch 1sh density remains constant - 150 m / m h).

90,100

110 120 130 140 150 160

That blint 1

70

67;

66

64 62 61 59 58

It is known that it is undesirable to turn the temperature of the rolls above 70-72 ° C, therefore, the basis of this table. 1, the central angle of 80 ° C is chosen as the minimum, and the maximum angle, since a further increase in the angle does not lead to a higher roll resistance. Thus, the results of an industrial experiment are in good agreement with the results of theoretical calculations, the zones of effective heat transfer are chosen according to the central angle of 80-150 ° C, In Table. 1 also presents the results of tests according to a known method. For this, the collector is installed in such a way that a coolant is supplied from one shell tangentially to the roll, t

-. "G, LA

From fnog. 3, it follows that the greatest increase in the heat transfer coefficient and its optimal values are observed when the irrigation density increases from 50 to 250 m / mg h. A further increase in the irrigation density leads to an inefficient use of the cooler. Laboratory results are validated under industrial conditions at the 2000 NLIZ mill. The experiment was carried out by rolling a yellow strip assortment (1.2 X 1250 mm art. 09КП). Irrigation density is adjustable by the way. pressure changes of the chiller. The cooling angle remains unchanged (150 °). Results Prev put in table. 2

table 2

5s

56 53

2.2 2.0

51 51

1.9 1.8

50 50

49 7 From table. 2 water, which does not increase irrigation over 250 hours, leads to inefficient use of the cooler. When the irrigation system is less than 50 m / mh, a sharp increase in the temperature of the rolls is observed, which leads to a decrease in the resistance of the rolls. Ø the last cages of the mill, having a lower heat load, when rolling heavy grades of steel, it is enough to supply 50-70 m of the cooler per 1 m of the surface of the rolls (the temperature of the rolls does not exceed 70 ° C). Thus, as a result of theoretical calculations, laboratory industrial research, the zone of effective heat removal from the roll, corresponding to the central Yasin angle of 80-150, and the irrigation density of 50-250 .h is determined. Found cooler feed parameters. ALLOW increase rolls resistance by

Claims (1)

ag.} 20-30% and at the same time reduce the consumption of the cooler by 12-15% due to it; more efficient use, which gives an economic effect on a single continuous broadband mill 150-200 thousand rubles; in year. The proposed roll cooling method is simple to implement and does not require sophisticated equipment. Claims The method of cooling the rolls, including the supply of a coolant to their surface, ex. Considering that, in order to increase the operational durability of the rolls and reduce the coolant consumption, the cooler is fed to the roll surface with the circumference angle of its circumference corresponding to the central yrfty 80-150 and the irrigation density of 50-250 m / m.