SU1409357A1 - Tool for manufacturing tubes by pushing through - Google Patents

Abstract

The invention relates to the processing of metals by pressure and can be used in the manufacture of seamless pipes by pushing. The purpose of the invention is to reduce the consumption of metal on the bottom edge. The push tool for pipe manufacturing includes a gauge and a stepped mandrel i with a thinned front end. The forming surface of the front end of the mandrel is made according to a curve, the parameters of which are determined by the dimensions of the steps of the mandrel, caliber and gap between them1 {. 1 ill., 1 tab.

Description

i

(L

00

ate

11А0

The invention relates to the processing of metals by pressure and can be used for the manufacture of seamless pipes, for example, for large-sized 1x superheaters in the nuclear power industry, cylinders, and seams for offshore drilling.

The purpose of the invention is to reduce the consumption of metal on the bottom edge.

The drawing shows the tool.

The tool contains a caliber 1 having a diameter D and a frame with a thinned front end 2 with a curvilinear generatrix, an end 3 having a diameter

f

and working part 4 with a diameter of d.

The forming surface of the front thinned end of the mandrel is made in a curve along the length allowed by the dependence

to (1 - b

),

(one)

de L TK the length of the thinned front end of the mandrel with a diameter at the end

zazbr between the caliber, having a diameter D, and the working stage of the mandrel, having a diameter d;

front end shape factor

one

2 - - 2 02

(2

For the manufacture of thick-walled sleeves, the shape of the front end of the mandrel is determined by

d.

de X dx the current value of the length of the thinned front end of the mandrel, starting from its end,

.45

50

diameter of the thinned front end of the mandrel at a distance X from its end

the size of the gap between the caliber and the working stage of the mandrel

full length of the thinned front end of the mandrel; diameter of the working stage op- ravki.

For such a mandrel, the front end odds ratio of the mandrel is defined by the expression

T L d f

(four)

D

where D is the diameter of the caliber.

For pushing thin-walled sleeves, the optimum shape of the front end of the mandrel is that it has the maximum allowable diameter values in any of its cross sections, ensuring the use of the full bearing capacity of the sleeve wall, which is determined by the ratio

d.

X

one

rI2 Y 2 -)

D

(five)

20

A form factor in this case is determined from the ratio

“2

-5g (s- | g)

g: 1 (G: 1b

(6)

25

five

0

five

The optimal shape of the front end of the mandrel, which provides the most favorable conditions for both the bottom part of the liner and the wall, is determined by the length from the end to

30 change of diameter from d. to d

Iff, (from d2

d2

)

not from

from dt () to d) expression

this 1 (.р к, L; and length

stk

NILE

(one),

wed z

expression (3), and on length- L (change in diameter

Cb

(5), with the second part b2U - K), where the values are determined from the ratio

from relation (4), and

L - ICP L, (1 H

from relation (6).

In the plane of exit from the caliber of the bottom part of the sleeve 5, its wall is only under the action of shear stresses from the forces acting on it from the end of the mandrel of the caliber. In this case, for its deformation, stresses are sufficient, equal to half the yield strength of the liner material.

As the end of the mandrel moves away from the gauge, and the effect of shear stresses on the strength of the liner wall decreases, ceasing when this distance becomes greater than the size of the gap between the gauge and the mandrel, as the angle between the axis of the broach and the direction of interaction the end of the mandrel and the caliber becomes less than 45 - angle

314

the action of maximum tangential stresses leading to shear deformation. Therefore, to avoid deformation of the wall from stresses less than the yield point, the distance between the forces acting on it from the side of the gauge and mandrel at the time the working stage leaves the gauge should be no less than the size of the gap between the gauge and the mandrel.

When the working stage of the mandrel comes out of the gauge, a full pushing force is transmitted to the wall of the sleeve.

neither Q, which is the equivalent of the middle end of the mandrel; Up KL. Giving force Q and P2. transmitted by the end of the lead-in front stage of the mandrel (Q) and the side surface (Q2) in the direction of pushing.

The force Q is applied at the location of the average diameter of the front end of the mandrel, which is determined from you. Jd + d

dtp u razheni located at a distance from the end of the frame.

The distance to the place of application of resultant Q from the place of application of force Q., i.e. from the end of the mandrel is equal to 1, and from the place of application of force 30 Q is equal to) - Iq. The moments of the forces Q, and Qj with respect to the place of application of their resultant Q are equivalent to the product of these forces and the distance to the place where the force Q is applied and equal to between -35, from where

Q, p (1 c, - IQ). (7-) The specific stress on the mandrel q is equal to the ratio of the total force Q to the cross-sectional area of the working

the substitution value Itj) "KL in expression (11) for 1e we have

kb (1 -1b

(12)

Since, in order to eliminate the effect of shear stresses on the strength of the liner wall, the place where the resultant O is applied must be from the working stage at a distance not less than the gap T between the caliber and the working stage of the mandrel, the length of the lead stage L must be at least 1c + T i.e. L5 IQ + T, from where

L - Ti KL (1 - jl).

(13)

40

When the lead-in stage is made with a ledge without a transition section to the working stage, lf, f L, while the lead-in stage should have

d

maximum length L T yy.

f

With the shape of the front end of the mandrel, the location of the average diameter is closer to the end face of 1cp CO, 5L. In this case, the length of the lead-off stage is always greater than T.

mandrel steps F 4Q

-d,. those. Yao

With the shape of the front end of the mandrel, the location of the average diameter is closer to the end face of 1cp CO, 5L. At the same time, the length of the lead-in stage is always greater than T.

Defined by the formula (1) length 45 thinned front end of the mandrel

completely eliminates non-contact deformation of the liner walls at the moment when the mandrel's working stage leaves the caliber when the stresses in them are less than the limit of the cross-sectional area 50 of the pipe metal yield b. working stage and the end of the mandrel, in order to exclude non-contact deformation of the sleeve wall at the moment when the end of the mandrel comes out of the front end- (8) 55 gauge,

the walls in this place should not exceed the value of b. Consequently,

 rsgr Q Force | is defined as the product of q and the end face area

r-d

piles equal to - and force Q is defined as the product of q at times //

- (d2 - dz), i.e. : Q, q.jdj, Q 4, f (d -df).

After substituting the values of Q, and O from expressions (8) and (9) into the equilibrium condition (7) and the corresponding transformations, it takes the form:

dflg. (d "-, - IQ). (ten)

whence q "l, p (1 -). (eleven)

Depending on the form (the front end of the mandrel l, we can take on different values. The ratio K

1-g is an indication of the shape of the front end of the mandrel; Up KL. By

the substitution value Itj) "KL in expression (11) for 1e we have

kb (1 -1b

(12)

Since, in order to eliminate the effect of shear stresses on the strength of the liner wall, the place where the resultant O is applied must be from the working stage at a distance not less than the gap T between the caliber and the working stage of the mandrel, the length of the lead stage L must be at least 1c + T i.e. L5 IQ + T, from where

L - Ti KL (1 - jl).

(13)

When the lead-in stage is made with a ledge without a transition section to the working stage, lf, f L, while the lead-in stage should have

d

maximum length L T yy.

f

With the shape of the front end of the mandrel, the location of the average diameter is closer to the end face of 1cp CO, 5L. At the same time, the length of the lead-in stage is always greater than T.

the force transmitted by the front end must not exceed

f (d ".

(14)

Allowable force of pulling Q is equal to

(-

- | (D2 - (15), where (D2-dn is the area of the gap between the caliber and the working stage of the mandrel, is equal to the cross-sectional area of the wall of the sleeve at the exit point of the working stage of the mandrel

5G

- (D - d) - the same 4

out of caliber as well

the place of exit from the gauge of the front end of the mandrel,

one

The total allowable pull force transmitted by the mandrel is Q - / 4d. (16) and is equal to Rdop determined from expression (15). The part of this force, equal to .Qy, transmitted by the end of the lead-in stage of the mandrel and defined by relation (8), in order to eliminate shear deformation when the end of the thinned front end of the mandrel leaves the gauge, should be no more than P | Q Qlfton C) from here on

U1y.gd. Wow with 17) QAO "Q

After substituting into this expression the values of the efforts, expressed in terms of stresses in the walls and on the mandrel from the imprints (8), (14), (16), we obtain:

J (D -dp

fit i

4 h,

about

eg j 7 | (D - d), dz q

where do we get the puff

-

-i- D2

After substitution of the value of D d + 2Т and the corresponding transformations into the output (2), it will become

d

year

d, 4

 . .

  7

(19) 50

The values thus determined from expressions (1) and (2), respectively, the length and diameter of the lead-in portion of the mandrel, make full use of the load-carrying capacity of the liner walls during drawing and at signs

093576

Equations in expressions (1) and (2) are optimal.

With a larger value of the diameter of the end face of the thinned front end of the frame

ten

15

20

25

thirty

ki d decreases the carrying capacity of the circumferential part, since shear deformation in this case occurs in it at forces less than the maximum permissible strength of the wall of the outstretched sleeve.

With smaller diameters of the thinned front end of the mandrel, the force of the sleeve stretching at this y4actKe increases, as well as the effect of the temperature difference between the bottom part of the sleeve and the wall in the area of the working step of the mandrel on the bearing capacity of the wall weakens it. In addition, as the diameter decreases and the length of the mandrel lead-in stage increases, metal consumption for pipe manufacturing increases due to an increase in the mass of the end waste due to an increase in the thickness and length of the transition section from the bottom to the wall of the sleeve.

After substituting the optimal value of the end face d, from expression (2) to the lowering (1), we obtain the lowering of the optimal length of the thinned front end of the mandrel

L 4

T

1 to

 5 - d2 / DZ

(20)

When the liner is drawn on the mandrel successively through several calibers, the length of the thinned front end of the mandrel is reduced in proportion to the reduction of the gap T - this follows from the extrusion (1), and vice versa when the length of the front end of the mandrel decreases by X its length L decreases; (1 - g)

Ij

times and accordingly the same amount decreases

T (1 -. Inflation (3)

gap T

optimal diameter value d

by

55

the length of the front end of the mandrel is obtained after the stand in the expression (9) instead of d | its current value d, and instead of T its current value

T, T (1 - f)

TO.

f

liL L

one

  d Jl, df D -

+ 1) - 1)

(21)

and after substituting the optimum diameter value from this expression from the expression (2) d, d / i - dVD, we obtain the expression (4) for the shape factor of the starting step

TO,

- ir) -.).

The formula (3) does not take into account the effect of a part of the rung length X up to the cross section of the mandrel with diameter d, on the allowable stresses in the walls of the liner. Therefore, the diameter values d are not the maximum allowed, and the length of the thinned front end of the mandrel, according to expression (20), is not the minimum.

The limiting shape of the thinned front end of the mandrel from the point of view of the maximum allowable stresses in the liner walls along the length of the front end of the step under the stretching conditions equal to the strength of the liner walls is determined by specifying a uniform change in stresses in the walls from b / 2 to 5 j . along the length of the runway.

those.

§If 1 2

) L

Where

- maximum allowable stress in the wall of the sleeve at a distance X from the end

3. QK

d

X

2dii, 1/1 ()

 () (i + 1

(26)

from where, after transformations, we obtain the expression (5) for the shape of the front end of the mandrel, having the maximum allowable diameter values in a decimal section and ensuring the use of the full bearing capacity of the liner wall

I 1 2 X7)

Value (5) at

X

L d.

determined from the expression

is etJd2 / i d × 7

cf. - H 2 s by definition coefficient of the formula K

2.r.di / D41 l, di / di)

and

2 4 d 7df d5 7DJ (di / d T taking into account the optimal value of 50

55

() g

2 –E D

wear tz; gj-: g - g we get the expression (6) for the shape factor of the thinned front end of the mandrel

  (3.) T) The length of the thinned front end of the mandrel is determined by substituting the K value from the expression (6) into formula (20).

TO.

The analysis of expressions (5) and (6) shows that such a mandrel has a lead-in stage with a convex shape of the lateral surface with a form factor K.

one

one

varying from m to g in the range of 0.1.

In real processes of pushing through

ratio: varies from the minimum

the values of r up to a maximum equal to 0.9; moreover, at fj it is a flow with

using the full carrying capacity of the wall is impossible, since bottom firmware will start earlier. When drawing thick-walled sleeves with

wearing g. 0.7 is optimal

the mandrel with the concave shape of the side surface of the thinned end of the mandrel in accordance with the extrusion (3). This shape of the mandrel provides maximum reinforcement of the bottom part of the liner by increasing the effective bottom thickness by 1 L - T. For example,

d2,

at fTj 1/3 form factor for

such a mandrel from the expression (4) is K 0.79, and L 1.46T. Accordingly, an effective increase in the bottom thickness will be IQ 1.46T, whereas for a mandrel with a convex shape of a thinned front end of the mandrel, only O, 22 T When pushing thin-walled

sleeves with a ratio of - 0.7 optimal

The shape of the thinned front end of the mandrel is progressive, providing a gradual buildup of stresses in the sleeve walls along the length of the front end of the mandrel and eliminating the effect of peak forces and temperature gradients as the bottom and transition part of the sleeve with a thickened wall penetrates the wall mandrel steps,

In practice, thick-walled and thin-walled sleeves are deformed on one mandrel. In this case, both conditions are met by a mandrel, in which the transverse part of the thinned front end of the mandrel is up to the average value.

diameter equal to d y 1/2 (d2 + d), is complete in accordance with the equation

(3), and adjacent to the working stage, in accordance with equation (5), with the length of the first part of the starting stage being equal to

one

K, L,,

(28)

and the second part 1 (1 - K), (29) where K and K are determined from equations (4) and (6), and L and L from equation (20), and the calculation is carried out for the maximum gap between the working mandrel level and caliber.

Example: To manufacture a pipe with an internal diameter of 390 mm and a wall of 60 mm, the original billet is used with a diameter of (9 760 mm from the outside And (410 mm from the inside).

According to the condition of the strength of the bottom of the liner, pushing with full use of the strength of the wall can be at a maximum ratio of the diameters of the caliber and mandrel equal to / T, which corresponds to the maximum value of the diameter of the caliber 390 / T 675 mm and the gap T 0.5 (675-390) 142.5 mm The design of the mandrel is calculated using a gauge size (675 mm, since with a mandrel diameter of 390 and a larger gauge size, the push stress is determined by the strength of the bottom, in which case the stresses in the walls are always less than the yield strength of the material.

The diameter of the end face of the thinned front end of the mandrel is determined by the formula (2)

d, 302 mm.

The shape factor of the first (concave) part of the thinned front end of the mandrel is determined from formula (4) and is equal to Kj 0.79, and the length of this section, taking into account equations (28) and (20), is equal to 1,164.5 mm, respectively

The shape factor of the second (convex) part of the feed stage is determined from formula (6) and is equal to K 0.455 and its length, taking into account expressions (29) and (20), is equal to 1 5 mm,

The total length of the thinned front end of the mandrel is equal to

L 1 g 2

The entry stage of the mandrel is made on the template (see table),

To estimate the economic efficiency, a device was chosen for drawing pipes through gauges containing a mandrel with a thinned front end.

Application on mandrels thinned front end of the proposed size

and the shape allows a 1.2-1.5 times increase in compression in the manufacture of pipes by pushing through gauges, as well as reducing the consumption of metal for the manufacture of pipes by reducing the bottom cut by 1.1 times.

Claims (1)

Invention Formula A pushing tool for pipes, containing a gauge and a stepped mandrel with a thinned front end, characterized in that, in order to reduce the metal consumption for the bottom cut, forming the surface of the front thinned end of the mandrel G1 1,285 (.  390 L / J 2,208, 2 L- .bt | 2-1 (1-.) Kf K. 174.2 curve on the length determined by t ---. 1 -K () where L is the length of the thinned front end of the mandrel with a diameter at the end; T is the gap between the caliber having a diameter D and the working stage of the mandrel having a diameter d; . K - front end shape factor with respect to 1, j..l  B - i 0.77 0.78 0.79 0.8 0.81 0.83 0.84 0.87 0.89 0.89 .0,9 0.93. 0.95 0.86 0.98 1.00 302 304.9 308.2 312 316.7 322.4 329.5 338.5 349 349 352.8 361.1 368.9 376.3 383.3 390 ABOUT 20.8 41.6 62.4 83.2 104.0 124.8 145.6 164.5 164.5 172.3 189.8 207.2 224.6 242 259.4 44 42.5 40.9 39 . 36.7 33.8 30.2 25.7 20.5 20.5 18.6 14.5 10.6 6.8 3.2 ABOUT