SU1620163A1 - Roll for cold periodic rolling of tubes - Google Patents

Abstract

The invention relates to pipe production and can be used in the manufacture of cold-formed pipes by rolling in several passes without intermediate heat treatment and pipes from low-plastic materials. The purpose of the invention is to increase productivity by reducing the vertical forces and efforts of breaking the working cone from the mandrel when applying the workpiece to the deformation zone. Angle of cross roll out (with relatively low ovality ratio) The invention relates to pipe production and can be used in the manufacture of cold-formed pipes by rolling in several passes without intermediate heat treatment and pipes from low-plastic materials. The purpose of the invention is to increase productivity by reducing the vertical forces and efforts to break the working cone from the mandrel when the workpiece is fed into the deformation zone. increased in the crimping zone in relation to the release angle in the reduction zone. At the same time, the maximum release angle along the entire length of the reduction zone provides the minimum stalling force. The maximum release angle in the middle of the reduction zone is determined by the release angle in the reduction zone of the hiring and the ovality coefficient. Red is determined by two factors: a small amount of rolling effort and an increased tangential expiration of the metal in this zone. The first of these factors makes an increased advertisement angle. optional, the second undesirable because of the possible formation of longitudinal folds on the inner surface of the reduced pipe section. The minimum angle is 2ed. It is taken from the condition of smooth conjugation when constructing the cross-section of the stream. The angle of the angle is in the range of 20-40 rad. The claims provide dependencies for a certain cross-sectional profile of a brook on both halves of the reduction zone. 2 z p fla, 1 tab., 4 ill. Figure 1 shows the gauge for cold piligrim tube rolling, a general view, in Figure 2 a section A-A in Figure 1; on fig.Z - section bb in figure 2; 4 - change the angle of release of the transverse profile on the length of the working part of the brook caliber (ACEFG - in the proposed stream, BKOFG - in the known). The creek of the pilger roll (figure 1) on an arc of 35-150 & corresponds to the compression zone of the pipe in diameter and wall in the stream of the caliber (Fig. 2) and therefore is hereinafter referred to as the reduction zone 0gc). SL С о ND О (Ј СЛЭ

Description

In order to ensure in each cross section a brook on the length of the zigzag area of the specified ratios of the values of Bx / Bx and "x indicated in the claims, the arc of a circle of radius release of the transverse profile is constructed so that the center of the circle is located on the straight line drawn through the middle of the chord, arc of a given release, perpendicular to this chord, and the location of one end of this chord (at the base of the release) is determined by the specified value Bx / AXi and the other end (at the release} by the specified value "X.

To improve the quality and increase the accuracy of rolled pipes, the limited radius of release to the radius of the semicircle at the beginning and end of the reduction zone is larger than in the middle of the reduction zone and.

The output angle of the stream cross section profile to the length of one half of the reduction zone is determined from i / ts

Zx x 1 hr ,,,

20 1P of reduction zone (X x - (X red b arccos (1 -

and on the length of the other half by the expression

Bh

. life safety fundamentals

X2h --- glad (g,

and X - and ed 4- arccos (1 - $ D X | obzh

where & ed is the angle of release of the cross-sectional profile of the cross section p% -h in the free reduction rad, rad;

Vh. Dx - u- irina and diameter of rui, mm;

In x

PJ - 1.03 - (, 05 - coefficient oval L

iosti

 - the length of the zone obzhas.

Xi and Ha - coordinates along the length, mm, poi

relation radius to radius

a semi-circle brook and the length of the reduction zone,

equal to 0.9 - 1.1.

The proposed relations (1) and (2) for changing the angle of release of the transverse profile make it possible to minimize the contact surface between the pipe and the mandrel in the middle of the reduction zone (Fig. 4). That angle is a. in the section, the stream in the beginning of the compression zone is not maximal; it eliminates the formation of longitudinal folds on the inner surface of the pipe in the event of its deformation along the diameter without deformation along the wall (free reduction) in this section, because in the actual rolling process the free reduction of the pipe in the section a stream corresponding to the beginning of the reduction zone often takes place (for example, if the wall thickness of the billet is less than the calculated one, in the case of

0

five

0

five

about

ABOUT

and

5 0 5

displacement of the mandrel with the rod in the rear position, with a short rod, and others.).

The fact that the angle a in the indicated area is larger than in the free reduction zone makes it possible to exclude a stream overflow with a small ovality coefficient of the transverse profile (within 1.03-1.05).

In addition, the character of the distribution of the angle a f "a to the length of the compression zone practically coincides with the distribution of vertical EFFORTS (especially when using mandrels with a curvilinear pattern of action), which contributes to the reduction of

a decrease in the angle a from the middle to the end of the reduction zone contributes, as in the above known well-known streams, to an increase in the precision of the rolled pipes. At the same time (unlike the known obuch), the Bx / Dx value is small over the entire length of the zone; In the proposed range of the ratio ri / r, the lower limit (, 90) establishes the maximum deformation of the pipe during the backward movement of the stand, g the upper limit (p / g 1.K) -) the linear area of contact between the pipe and the support Chyrzotsch reduction of the force for breaking the pipe from the mandrel. The specified - the limits of the ratio ri / r are set by the xperimental (see table)

BECAUSE the NSS-zhcnomerna deformation of the pipe in the transverse outlets of the stream in the sections at the beginning and end of the reduction zone contributes to the deterioration of the quality of the prog.shrednye pipes and at the same time in the area in the middle of the reduction zone the effect of deformation in the outlets on the quality of pipes mim / But it is advisable, in the border zone -.trjx, the degree of removal of the gas pump at the beginning and the end of the zone, in areas of length (0.1 - 0, °), was larger than in the middle of this zone.

Offered and well-known (prototype) hand-and-and other options for rolling (table) were tested in the calibers of the HPT 32 mill when rolling tubes of titanium alloys using a non-heat-treated cold-rolled billet strengthened as a result of previous rolling in the HPT mill.

In the proposed stream, the construction of the arc — the release of the cross-sectional profile of the process — is as follows (see FIG. 3).

The location of the ends of the speaker chord, which produces an arc of release, is determined by the known correspondence between

the width and diameter of the brook V / D 1.05 (point C) and at the calculated release angle (point A), then through the middle of the speaker chord, Oi M was perpendicular to it.

The length of the segments AK and SK was chosen equal to the radius n of the arc of the outlet circle for a given ratio n / r, the value of which at the beginning and end of the reduction zone (at 45 °) was assumed to be 1.00, and in the middle of the reduction zone was equal to 0 90.

In a well-known brook, the release angle a was reduced along the length of the reduction zone (on an arc around a circumference of a caliber from 35 to 140 °, see the OF slice in FIG. 4) from the angle n, equal to a max in the proposed brook, to a value equal to a min, in the proposed stream, according to the law of a straight line, since in this way the angle a in the known stream varies as a function of the n / a ratio. The ratio p / r decreased from 1.07 at the beginning to 1.04 at the end of the reduction zone,

In the process of pipe rolling in gauges with the proposed stream, the uneven feed of the billet to the deformation center along the stroke of the feed screw (feed spread) was 2 mm, there were no overshoots of the billet, the surface quality and the geometrical dimensions of the rolled tubes met the established requirements.

In the process of pipe rolling in calibers with a known stream, a spread of feed of up to 6 mm was observed and the billet rolls periodically occurred.

Performance compared with rolling in calibers with the proposed stream was on average 25-30% lower. On the outer surface of the rolled pipes in some places there were characteristic snacks and sunsets, due to the throws of the workpiece.

The use of the invention allows to increase productivity by 25-25%, reduce the power parameters of the rolling process and improve the quality of multipass cold-rolled (heat-rolled) pipes manufactured without intermediate heat treatment between individual passages and pipes of low-plastic materials, increasing the yield of average by 12 -18%.

Claims (3)

1. Roller for periodically cold rolling of tubes, including a barrel with a stream around the circumference, having a free-reduction zone and a reduction zone adjacent to it, reducing along the length of a semicircular cross-section with symmetrical radius releases and a variable angle of release, about l and h and with the fact that, in order to increase productivity by reducing the vertical forces and the effort to break the working cone from the mandrel when the workpiece is fed to the deformation zone, the output angle ax is the cross-sectional profile of the brook over the length of one sex the reduction zone is defined by the expression ah Sered + arccos (1 - Xi, 1о5ж; and the length of the other half of the reduction zone is 15  "Ed + arccos (1 V X I compress -X 2 2DX life safety fundamentals ). where "ed is the angle of release of the cross-sectional profile of the stream in the zone of free reduction, rad; Bx and Dx - width and diameter of the stream profile in cross section X at the length of the reduction zone, respectively, mm; Vx / Dx 1.03 ... 1.05 - coefficient of ovality of the stream profile at the length of the reduction zone; Obzhi - the length of the zone of reduction in the stream caliber, mm; Xi and X2 - the current coordinate on the length of the one and the other half of the reduction zone, mm, with 0 Xi 10bj / 2 and 0bj / 2 X2 compression, with respect to the radius of release to the radius of the semicircle, the brook on the length of the reduction zone is in the range of 0.90-1.10. 2. Rolls according to claim 1, characterized in that the center of the arc of a circle of radius of release is placed on a straight line drawn through the seoid and perpendicular to the chord that expands the arc of release, and the location of the end of the chord at the base of the release is determined by a given value of 8x / Dx, and konce.a at the top of the release - for a given value of «x. 3. Rolls according to claims 1 and 2, characterized in that, in order to improve the quality and increase the accuracy of rolled pipes, the ratio of the release radius to the radius of the semicircle at the beginning and end of the reduction zone is greater than in the middle of the reduction zone. ft (V) 1H J x0 ct pad fe.J 25