SU1202646A1 - Method of tube lengthwise rolling (its versions) - Google Patents

Abstract

1. A method of longitudinal rolling of tubes, including the introduction of lubrication: into the sleeve and the deformation of the sleeve on the mandrel by calibrated rollers, the distance between which is increased during the rolling time taking into account the difference in temperature and thickness of the wall of the front and rear ends of the sleeve, characterized by that, in order to reduce the pipe's spacing by adjusting the friction coefficient value between the tube and the mandrel, the lubricant is fed into the sleeve simultaneously with the change in the distance between the rollers and the amount is reduced by the same factor ent, which increases the distance between the rollers. 2. A method for the longitudinal rolling of pipes, including the introduction of lubricant into the sleeve and the deformation of the sleeve on the mandrel by calibrated rollers, the distance between which is increased during rolling taking into account the temperature difference and the wall thickness of the front and rear ends of the sleeve. reducing the pipe pipe fracture by adjusting the value of the coefficient of friction between the pipe and the mandrel, is fed into the sleeve simultaneously with changing the distance between the rollers of lubricants discretely different in anti-friction properties of lubricant, reducing its TWA by the same coefficient by which the distance between the rollers increases. S (L o o GcheE O5 4 S

Description

one

The invention relates to pipe rolling npoHSBOflCfBy, in particular to the production of hot-rolled, seamless pipes in longitudinal mills

rolling.

The purpose of the invention is to reduce the pipe difference by adjusting the value of the coefficient of friction between the pipe and the mandrel.

PRI me R. When rolling a rough tube 13612 mm long Hume with a temperature difference along the length of 120 ° С, the sleeve obtained at piercing Astana has dimensions 147-14 mm and different temperatures along the length: 940 at the front and 1060 at the rear ends, which measures The sensor of the software system for controlling the operation of the pressure device and lubricant supply equipment. Such a temperature difference (120 ° C) leads to the formation of the longitudinal difference of 1, 2. mm pipes. Eliminating the difference in such a value requires a uniform reduction in the distance between the rollers and the mandrel, respectively, by 2.4 mm during the rolling process of the entire pipe, which is 20% of the nominal wall thickness of the draft pipe (12 mm).

Thus, the rolling of said tube 136-12 mm with a length of 10 m should be carried out with a change in the distance between the rollers and the mandrel by 0.24 mm per meter of pipe.

The required level of variation of the distance between the rollers and the mandrel by 20% of the nominal pipe wall thickness is interrelated with the change in the value of the coefficient of friction on the mandrel, which can be achieved by a corresponding decrease in the amount of lubricant supplied or by the supply of lubricant with reduced anti-friction properties.

In the first embodiment, in addition to supplying the lubricant to the pre-deformation zone on the mandrel, before rolling, lubricant is fed into the sleeve simultaneously with the movement of the rolls, for example powdered sodium tripolyphosphate, while its amount is changed inversely proportional to the change in the distance between the rollers and the mandrel.

, The magnitude of the change in the distance between the rollers and the mandrel when rolling various parts of the pipe front, middle and rear ends

02646 2

the tubes are respectively 2.4, 1.2, and O mm, or 20, 10, and 0% of the nominal wall thickness of the rolled pipe (2 mm).

5 The ratios of friction coefficients and the amount of lubricant supplied, required with a corresponding change in the position of the rolls to 20% relative to their initial position, in a vertical plane for rolling a given nominal pipe wall thickness I2 mm are given in Table. one.

Before the task of the front more

15 cold end of liner (i- 940 °)

The longitudinal rolling mill rolls reduce the distance between the rolls and the mandrel by 2.4 mm relative to their adjusting position or 20% of the nominal wall thickness by command of the program control system for the drive of the vertical movement of the upper roll. At the same time, the lubricant in the amount of 2.62 cm / m is additionally supplied to the pre-focal deformation zone at the same time, for example, by blowing with compressed air powdered sodium tripolyphosphate, the amount of Q in which depends on the pressure of compressed air and the diameter of the hole through which it is fed into the air line that ensures the formation of a layer of lubricant with a thickness of 0.04 mm and the value of the coefficient of friction on the mandrel is 0.11. Thus, if we take the friction coefficient on the mandrel under normal conditions, then when rolling the front end of the pipe, when the rolls are previously reduced to the value of 20% of the nominal thickness, it is necessary to reduce the value of the friction coefficient from 0.14 to 0.11, t. e. by the value of 0.03.

When rolling the middle of the pipe

35

40

45

50

and 1000 °) the gap between the rollers and the mandrel is changed by a value of 1.2 mm, i.e. 10% relative to the nominal wall thickness. At the same time, lubricant in the amount of 2.06 cm / m is supplied to the pre-focal deformation zone, which ensures the formation of a layer of lubricant with a thickness of 0.055 mm and a value of the coefficient of friction on the mandrel of 0.125. 55 when rolling the back, the most heated end of the pipe (-t 1060 °), the rolls are moved to the tuning position (reduction - 0% relative -.

but the nominal pipe wall thickness. In this case, additional lubrication is not served, which provides the value of the coefficient of friction - 0.150, due to the use of a basic lubricant.

As can be seen from the table. 1, by changing the initial thickness of the lubrication layer, the amount additionally fed into the gap between the sleeve and the mandrel), for example, increasing it from 0 to 0.07 mm reduces the coefficient of friction on the mandrel from 0.14 to 0.11, i.e. . when rolling pipes of size 136–12 mm on TPA-140, the correspondence between the amount of change in the distance between the roll and the mandrel and the value of the friction coefficient should be observed: when the distance between the rollers and the mandrel is reduced by 20% of the nominal wall-pipe thickness, the coefficient of friction on the mandrel should be reduced by 0.03 by supplying additional lubricant in the amount of 2.62.

A similar effect when rolling the pipe according to the proposed method can be obtained in the second embodiment, i.e. in the case of additional lubricant supply, discrete with different anti-friction properties in the pre-strain zone of deformation simultaneously with the movement of the rolls and change of its properties depending on inversely proportional to the change in the distance between the rolls and the mandrel. Another type of lubricant or various mixtures of them can also be increased or decreased. the coefficient of friction on the mandrel.

Specific types of additionally supplied lubricants to obtain the required friction coefficients between the mandrel and the tube, required with a corresponding change in the position of the rolls by 20% relative to their initial position in the vertical plane for rolling the specified nominal wall thickness of 12 mm, are given in Table. 2

When rolling a pipe under the conditions described in the first variant of the proposed method, to obtain the required friction coefficients between the pipe and mandrel, as can be seen from the table. 2, three types of lubricants with different anti-friction properties should be used, for example, cooks 026464

salt, graphite, sodium tripolyphosphate, etc.

When rolling the front end of the pipe, it is possible to use tripolyphos-5 grease lubricant with higher antifriction properties and providing a coefficient of friction between the pipe and mandrel 0.11, while rolling the middle section 10 of the pipe - graphite lubricant, increasing the coefficient of friction to 0.125, and the rear section - to 0.14.

Discrete delivery of additional 15 lubricants with different anti-friction properties, when rolling pipe sections with different temperatures, is carried out, for example, by supplying lubricant in a steam-20 shaped state in separate containers located on a trunk of a rotating device coupled to a rod for supplying lubricant with compressed air 25 to the pre-focal zone.

In the case of an increase or decrease in temperature difference, it is necessary according to the first variant, respectively 3Q, to increase or decrease the difference in the additional quantity of lubricant supplied along the length of the rolled pipe, and according to the second variant, it is supplied. vat SEE additional lubricants respectively with more or less35

40

45

50

55

Shim honors antifriction properties.

In the proposed method, the longitudinal difference wall of the pipe obtained at the tops of the gauge is reduced by moving the rolls in the rolling process by the amount of change in the elastic deformation of the mill stand and thereby keeping the distance between the rollers and the mandrel constant} the coefficient of friction at the point of contact of the liner and the mandrel, as well as improved accuracy of rolled pipes due to a decrease in the longitudinal difference in the wall-to-wall and in the outcrops of feces ibrov, which makes it possible to roll the pipes in the minus tolerance field and, upon delivery of them, by theoretical weight, ensure an increase in production up to 5%.

Rear end of guillotine Salt 0% (O mm) (NaCl)

f

The middle part of the pipe is 10% (1.2 mm) Graphite

Front end

Glzy 20% (2,4mm) Tripolyphosphate

nitri

Compiled by L. Maturin. Editor N. Dankulich Tehred T. Tulik. Corrector I. Muska,

Order 8350 / 8Distribution 548Subscription

VNIIPI USSR State Committee

on affairs of inventions and discoveries 113035, Moscow, Zh-35, Raushsk na5., d, 4/5

Branch PPP Patent, Uzhgorod, st. Project, 4

Table 1

0.14

0.125

4-5

0.1 1

8-10

Claims (2)

1. A method of longitudinal rolling of pipes, including the introduction of grease: into the sleeve and deformation — the sleeves on the mandrel with calibrated rolls, the distance between which is increased during the rolling process taking into account the difference in temperature and thickness of the wall of the front and rear ends of the sleeve, characterized in that, with the goal of reducing different. pipe wall by adjusting the value of the coefficient of friction between the pipe and the mandrel, the supply of lubricant to the sleeve is carried out simultaneously with a change in the distance between the rollers and its quantity is reduced by the same coefficient by which the distance between the rollers is increased. 2. A method of longitudinal rolling of pipes, including the introduction of lubricant into the sleeve and the deformation of the sleeve on the mandrel with calibrated rolls, the distance between which is increased during the rolling process taking into account the difference in temperature and wall thicknesses of the front and rear ends of the sleeve, characterized in that, in order to reduce the difference in pipes by adjusting the value of the coefficient of friction between the pipe and the mandrel, they are fed into the sleeve simultaneously with a change in the distance between the rolls, lubricants discretely different in anti-friction properties, reducing properties by t The same coefficient by which the distance between the rolls is increased.