US2084330A

US2084330A - Seamless pipe or tube mill

Info

Publication number: US2084330A
Application number: US754168A
Authority: US
Inventors: Findlater Stevenson
Original assignee: National Tube Co
Current assignee: National Tube Co
Priority date: 1934-11-21
Filing date: 1934-11-21
Publication date: 1937-06-22
Anticipated expiration: 1954-06-22

Description

June f22, 1937.

s. FINDLATER Y SEAMLESS PIPE OR TUBE MILL Filed Nov. 21, 1954 5 Sheets-Sheet; 1

[Me-Wallon" I STEL/ENSO/V HNQL ,47E/ve,

June 22, 1937. Q FINDLATER 2,084,330

sEAMLEss PIPE 0R TUBE MILL Filed Nov. 2l, 1954 3 Sheets-Sheet 2 [7c/venan' STEVENSON HNDLA'TEE,

June 22, 1937.`

, SEAMLESS PIPEA OR TUBE MILL 3 Sheets-Sheet 3 yFiled Nov. 21, 19:54

16e 50 /6 764 J0 "al l 1.( v El f 5 'Jil i I \4 16?/ a lEn@ 24 al 109g /095 al [aww/Libr:

STEVENSQN F/NDLATE/e) l 15 spective surfaces will be closer together.

Patented June 22, 1937 UNITED STATES SEAMLESS PIPE OR TUBE MILL Stevenson Findlater, McKeesport, Pa., assigner to National Tube Company, a corporation of New Jersey Application November 21, 1934, Serial No. 754,168

4 Claims.

This invention relates to improvements in seamless pipe or tube mills, and more particularly to the compensation for changes in the size of the pass due to the expansive influence 5 of the highly heated\workpiece.

In the manufacture of seamless pipes and tubes, considerable difficulty has been experienced in maintaining constant the distance between the various roll faces and the surfaces of the l0 mandrel plug, due to the expansion of the rolls,

mandrel plug and of the mandrel bar supporting the plug. That is to say, as the rolls and mandrel plug acquire heat from the work-pieces being processed they will expand and their re- Similarly, as the mandrel bar acquires heat it will increase in length and move the mandrel plug further into the metal pass and, accordingly, closer to the surfaces of the rolls. This decreased 20 distance between the various metal working surfaces causes the wall thickness of the Work-piece being processed to vary, due to a more substantial reduction in the wall of the work-piece when the rolls and mandrel bar are hot than would be the 25 case were they cold.

The temperature of a seamless pipe or tube mill is usually no higher at the end of a long period of operation than it was at the beginning.

This is for the reason that the mill is started 30 without cooling water on the rolls and heated billets passed therethrough until the rollsr acquire a desired temperature. At this time the rolls are sprayed with Water in order that the temperature will not rise greatly beyond that 35 desired. In this. manner the general temperature of the mill is maintained as desired, but as each highly heated billet, or work-piece, moves through it, the temperature of its elements is 'temporarily raised. This temporary rise in tem- 40 perature causes a correspondingly temporary expansion, particularly ofthe mandrel bar; the effects of which the present'invention seeks to avoid.

In addition, it is often desirable to regulate the relative positions, of various metal Working rolls, even when cold, in accordance with the temperature of the work-piece, and thus modify the pressure thereof in order to obviate variances in the product. In a copending application entitled Apparatus for `making tapered workpieces filed December 29, 1934 and bearing Serial Number 759,803, I have disclosed apparatus which is in many respects similar tothat disclosed herein. 'I'his copending application is, 55 however, concerned with making a tubular workpiece which is tapered in both outside diameter and wall thickness; and the apparatus thereof is therefore constructed and arranged to accomplish this result by enlarging the pass.

One object of the invention is to provide novel means for automatically compensating to exactness for the expansion of metal working rolls and maintain constant the distance between the surfaces of the various rolls.

Another bject is the provision of novel automatically actuated mechanism for withdrawing either and/or a work roll or rolls or an idle roll or rolls in exact ratio to the expansion thereof.

A further object of the invention is to provide a novel mechanism for automatically withdrawing a roll or rolls in exact ratio to the expansion of the mandrel bar and/or the metal working rolls of a seamless tube mill, resulting in a constantlymaintained distance between all of the various metal working surfaces.

A still further object is to provide automatic and powerful means, operating under a heavy thrust, for moving at least one roll from the roll pass slowly and in exact ratio with the expansion of metal Working rolls and/or the expansion of a mandrel bar, together with automatically actuated means for stopping the operation of said rst named means and rapidly returning the roll or rolls to their original relative posi-- tions.

A still further object is to provide a novel construction of the class described which can be installed on existing mills with but little modification and expense.

These and further objects of the invention will appear after referring to the drawings, in l which:

Figure 1 is a plan showingthe apparatus of p the inventionl applied to a seamless tube mili with the work-piece in section.

Figure 2 is a view taken on the une 11-11v of type, but might well be of any of the well known constructions. Ordinarily, in seamless tube practice both of the rolls 2 vwill be power actuated, -but itis to be understood that one; of -thesame may be idle, and it is even within thel contemplation of the invention to apply the principles thereof to any metal working mill employing a plurality or multiplicity of rolls which may be, according to the invention, modified as to their relative positions, either in combination or otherwise.

Each of the rolls 2 is mounted on a shaft 3 and driven through suitable mechanism, such as a gear B and pinion B', the latter having an elongated surface to permit relative longitudinal movement of the gear B and shaft 3 on which it is mounted.

A mandrel bar 4 isdisposed in the longitudinal direction of feed of a work-piece, or tube A, and provided on one of its ends with a mandrel plug 4a which is adapted to internally support the work-piece while it is being processed by the rolls 2. l

A suitable coupling 3 is provided for connecting one of the roll shafts 3 to a screw 5 in such manner as to permit independent rotation of the roll shaft. The screw 5 is disposed in a nut 6 which is journaled for rotation in suitable bearings 1. A worm Wheel 8 is keyed to the nut 6 for rotation therewith, and is in mesh with a worm 9, which is mounted on a shaft I8 of a vlarge gear II.

A motor I2 is positioned somewhat adjacent the large gear II and has a pinion I3 associated therewith for rotating a gear I 4 which is mounted on a shaft I5. The shaft I5 carries one member of a magnetic clutch, generally indicated at I6, while a cooperating shaft I5a carries the` cooperating clutch member. A pinion I1 is mounted on the shaft I 5a and in mesh with a gear I8, which is mounted on one end of a shaft I9. The shaft I9 is provided at its other end with a pinion 20 which is in constant mesh with the large gear II. i

A second motor 22 is positioned somewhat closer to the large gear II and is provided with a pinion 23 which is in constant mesh therewith.

A suitable magnetic brake, generally indicated at.

24, is provided for the motor 22.

The rotation of the motor I2 is automatically compensated for diiferences in resistance to metal displacement caused by introducing metal of varying temperatures into the rolls. The operation is such that the variation in temperature of the work-piece being processed, as measured by photoelectric, optical radiation, or other pyrometer, will be transmitted to the compensator motor I2, in such manner as to increase or retard the rotation thereof, thereby varying `the rate,4 at which the compensator operates.

Any suitable and conventional electric wiring circuits, including the pyrometer device, relays,

and preferably also push-buttons, are provided for the motors I2 and 22, the magnetic clutch device I6, and the magnetic b rake 24 for the motor 22.

In operation, a. tube A, which is shown as having been previously pierced, is introduced between the rolls 2, while supported internally by the mandrel plug 4B. The tube continues through the mill until a suitable load relay, or push-button, is operated to energize the magnetic clutch I6 and release the magnetic brake 24, the rate of rotation of the shaft of the motor I2 being controlled through the suitable resistance mentioned.

' The rotation of this shaft permits-the motor pinion I3, driving through the mechanism, or gear train I4, I1, I8, 20, II, 9 and 8 to rotate the nut 6 and withdraw the screw 5, thereby correcting or maintaining the distance between the rolls 2 and the surfaces of the mandrel plug 4a.

After the motor I2 has been actuated tocause the screw 5 to be retracted sumciently by the nut 6, the return movement of the roll must be quickly effected pending the arrival of the next tube. As the pinion 23 on the shaft of the motor 22 is in constant mesh with the large gear II, a suitable relay, or the operator attending the device, momentarily energizes the magnetic brake 24 for the motor 22. This operation at the same time instantaneously deenergizes the magnetic clutch I6 and disengages the motor I2. The motor 22 is then actuated to reverse the motion of the gear II to rapidly return the roll to a position predetermined by suitable limit switches which automatically stop the motor 22 and at the same time applies the brake 24.

When the motor 22 is energized, the large gear II, which is in constant mesh with the pinion 23, causes the latter, gear I8 and pinion I1 to rotate,

since the pinion 20 and gear Ill are mounted when the motion transmitted by the motor 22 returns the roll to the position required for the entry of the next tube.

Referring to Figures 4 and 5 of the drawings,

I have disclosed, in a diagram, one form of electrical control which willfunction to operate thel elements of the invention in the manner previously described. In this diagram the numerals 30 and 3I designate suitable power lines carrying a normal voltage; such as 220 V.

A master switch A33 is -provided for operating the motor I2, which serves to retract one of the metal working rolls 2, and is connected between the power lines 38 and 3l by a line 34. The master switch 33 is provided with an operating lever 35 and the

usual contacts

36, 31, 38, 39, 40 and 4I. A low-voltage coil 43 is connected in the line 34 for the master switch 33, and hastwo .pairs of contacts 43a and 43b which it serves to actuate.

The contact 36 of the master switch 33 is connected to the line 34, between the low-voltage coil 43 and its contacts 43, by a line 45. A line 46 connects the contact 31 of the master switch 33 tothe line 34 through the contacts 43b of the low-voltage coil 43 and has included therein a pair of coils 41.

A line 48 is connected to the contact 38 of the master switch 33 and has included therein an auxiliary switch 53, while a line 49 is connected to the contact 39 and has included therein an auxiliary switch 411. connected to the line 34 through the contacts 43b of the low-voltage coil 43 by a line 50 which has included therein a coil 5I.

The contact of the master switch 33 is connected to the line 34 through the contacts 43b of the low-voltage coil 43 by a line 52 in which there is included a pair of coils 53.

A line 54 is provided for connecting the contact 4I of the master switch 33 through the contacts 43b of the low-voltage coil 43, and includes a series of

coils

55, 56 and 51, together with an auxiliary switch 5Ib. 'Ihe auxiliary switches 41a and 53'* are operated by the

coils

41 and 53, respectively.

`rl'he motor I2 is connected to the power lines 30 and 3I by a line 56 and includes in its circuit contacts 41b and 41c and 53b and 53e, which are The' lines 48 and 49 are operated bythe

coils

41 and 53, respectively. A' series of

contacts

55, 56 and 51, are also included in the line 56, together with a pair of contacts 5|. '

I'he contacts

55, 56 and 51EL are operated by the series of

coils

55, 56 and 51, respectively. The auxiliary switch 5|b and the contacts 5|n are both operated by the coil 5|.

'I'hephotoelectric pyrometer device X is connected by a line 59 with a series of relays 60, 6|, 62, 63, 64 and 65, which in turn operate a field rheostat 66. Each of these relays is adjusted to trip at a definite temperature. This field rheostat is connected in a line 61 between the

power lines

30, and 3|, with the shunt eld for the motor I2, which is designated at I2, and a hand operated rheostat 68.

'Referring to Figure 5 of the drawings, it is to be noted that the motor for rotating the metal working rolls 2 is indicated at 10, being connected by a line 1| with

suitable power lines

12 and 13. While one motor 10 is illustrated in the drawings and may be used to drive both metal working rolls 2 through the medium of\suitable gearing (not shown), the invention also contemplates the driving of each roll with an individual motor. The

power lines

12 and 13 furnish the motor 10 with current ofa considerably higher voltage thanthat furnished through the

power lines

30 and 3|; as for instance 600 volts. A shunt 14 is included in the line 1| between the power line 12 and the motor 10. A line 15 connects the shunt 14 with one end of a load relay 16. Another line 11 connects the shunt 14 with the other end of the load relay 16 and has included'therein a limit switch 18.

The magnetic clutch I6 which is' carried on the shafts |5 and I5 is connected between the

power lines

30 and 3| by a line 80, which has included therein two pairs of contacts, as at 16 and 16h. The magnetic brake 24 for the motor 22 is connected by a line 8| with the

power lines

30 and 3|, and includes in circuit on each side thereof a pair of contacts, as at |09 and |09, respectively.V i

A line 83 is connected to the line 80 between the power line 30 and the contacts 16 and to the line 8| between the contacts |09 and the magnetic brake 24, and includes a pair of contacts 16. A similar line 84 is connected to the line 80 between the power line 3| and the contacts 16b and to the line 8| between the contacts |09 and the magnetic brake 24 and includes a pair of contacts 16d. A

'I'he contacts 16B, 16h, 16 and 16d are all. operated by the load relay 16.

and has two pairs of contacts 96 and 96b whichl it serves to operate.

'I'he contact 89 of the master switch 86 is connected to the line 81 between the low voltage. coil 96 andits contacts 96 by a line 91.

A line 98 connects the contact 90 of the master switch 86 to the line 81 through the contacts '96b.of the low-voltage coil 96 and includes therein a limit switch and a. pair of coils |0I.

.A line |02 is connected to the contact 9| of the master switch 86 and includes a limit switch |03 and an auxiliary switch H3, while a line |05 is connected to the contact 92 of the master switch 86 and has included therein a limit switch I06and an auxiliary switch I0|. The lines |02 and |05 are connected to the line 81 through the contacts 96b of the low-voltage coil 96 by a line |08 which has included therein a pair of coils |09.

The contact 93 of the master switch 66 is connected to the line 81 through the contacts 96b of the low-voltage coil 96 by a line ||0 which has included therein a limit switch ||2 and a pair of coils II3.

The-1mm switches loo and los are suitably arranged to open when the motor 22 has placed the metal working roll 2 in its original position in the mill, while the limit switches |06 and ||2 are arranged to open when the roll is in its extreme remote position with respect thereto.

A line II4 connects the contact 94 of the master switch 86 to the line 81 through the contacts 96h of the low-Voltage coil 96 and includes a series of ycoils II5, I|6 and II1, and an auxiliary j auxiliary switches IOI' and II3 are operated by the coils |0I and' I3, respectively.

The motor 22 is connected to the power lines and 3| by a line |22 and includes in its circuit contacts |0|b and |0|c and H3b and H3C, which are also operated by the coils -I0| and ||3, re-

spectively. The series'eld forthe motor 22 is 'Y included in this line |22, beingdesignated at 22, and also aseries of contacts |I5, IIS and II1, which are operated by the coils 5, ||6 and |I1, respectively. A pair of contacts |09c are also included in a line |22 betweenl the series of contacts |I5, H63, and II1a and the power line 3|.

The contacts |09, |09, |09c and the auxiliary switch |||9d are all operated by the coils |09.

In operation: The operator of the mill moves the lever of the master switch 33 to the out position. At the time the lever 35 was resting in the off position, the low-voltage coil v43 was closed, and is maintained by one of its contacts 43. The movement of the lever 35 closes the

contacts

39, 40 and 4I of the master switch, thus energizing the coil 53 to close the contacts of the auxiliary switch 53 and the contacts 53b and 63e; and the coil 5| to close the contacts 5|, and the contacts of the auxiliary switch 5| b. 'I'he closing of the contacts of the auxiliary switch 5|b energizes the

coils

55, 56 and 51, thus closing the

contacts

55, 56a and 51. Upon the closing of the

contacts

55, 56a and 51 the motor I2 will rotate at a speed predetermined by the setting of the hand operated rheostat 68.

At the time of moving the lever 35 of the master switch 33 to the out position, the operator also moves the lever 88 of the master switch 86 to the in position. No operation results from this last named movement due to the fact that the metal working rolls 2 are in position to receive the work-piece A and the limit switches |00 and |03 are open.

As the work-piece A moves between the metal working rolls 2 and over the mandrel plug 4, the power required by the motor 10 passes through the shunt 14. The voltage drop across the shunt energizes the load relay 16 which closes the contacts 16a, 16", 16c and 16d and opens the auxiliary switch 16. The closing of the contacts 16,, 16h, 16c and 16d energizes the magnetic clutch I6 and the magnetic brake 24. In this manner the motor I 2 is caused to rotate the nut 6 to withdraw one of the metal working rolls 2. The speed with which the motor I2 initially operates is, of course, determined by the setting of the hand operate-d rheostat 68, as previously mentioned.

The photoelectric pyrometer device X is set for a predetermined temperature indication and if the temperature of the work-piece A, as it passes the point upon which it is trained is either `above or below this indication, the relays 60 to 65, inclusive, are caused to function. The functioning of the relays 60 to 05, inclusive, will include or delete sections of the field rheostat 66, to increase or decrease the speed of operation of the motor I2, which Vis withdrawing one of the metal working rolls 2. It will thus be s'een that this rate of withdrawal is in direct proportion to the temperature of the work-piece A.

The power required by the motor, or motors, "I0, which drives the metal working rolls 2, will approach zero after the trailing end of the workpiece A has emerged from the mill. This causes the voltage drop across the shunt 'I4 to approach zero, and the consequent deenergization of the load relay 16. The deenergization of the load relay I6 causes the opening of the contacts 16, 161, 'I6c and 1611, to deenergize the magnetic clutch I6 and the magnetic brake 24. The motor I2 is thus caused to cease the withdrawal of the metal working roll 2.

The closing of the contacts of the auxiliary switch |09d energizes the coils ||5, I6 and to close the contacts H521, |||a and lla. This brings the motor 22 up to full speed,

The entire equipment is thus set for another cycle of operation, which is again initiated by the operation of the mill in the manner previously described.

While I have shown and described certain speciiic embodiments of my invention, it will be understood that I do not wish to be limited thereto, since'various modifications may be made without departing from the scope of my invention, as deiined by the following claims.

I claim:

1. A metal working roll adjusting mechanism comprising a screw associated with said roll, a nut on said screw, a worm gear on said nut, a

worm for said worm gear, a gear for rotating' said worm, a pinion for said last named gear, a motor and reduced gearing associated with said pinion for rotating said screw to move said roll away from a work-piece being processed thereby, a second motor for rapidly returning said roll to its initial position, and a driving connection between said last named motor and the gear for rotating said worm.

2. A seamless pipe or tube mill comprising, in combination, at least one power actuated metal working roll, a roll for `croacting with said rst named roll, a mandrel bar, a mandrel plug supported by said mandrel bar, said mandrel \lug being disposed intermediate said rolls, means for slowly withdrawing at least one of said rolls to compensate for expansion and maintain substantially constant the distance between said rolls and the surfaces of said mandrel plug while a pipe or tube is being acted upon thereby, a'means responsive to the temperature of said pipe or tube forcontrolling the operation of said last named means, and means for returning said second named roll to its=initial position.

3. A seamless pipe or tube mill'comprising, in combination, at least one power actuated metal working roll, a roll for coacting with said first named roll, a mandrel plug' disposed intermediate said rolls, means forwithdiawing at least one of said rolls to maintain a desired relationship between said rolls and the surfaces of -said mandrel plug while a pipe or tube is being acted upon thereby, means responsive to the temperature of said pipe or' tube for controlling the speed of operation of said withdrawing means, and meansA for returningthe withdrawn roll to its initial` position.

4. A seamless pipe or tube mill comprising, in combination, at least one power actuated metal working roll, a roll for coacting with said first named roll, a mandrel bar, a mandrel plug supported by said mandrel bar, said mandrel plug being disposed intermediate said first and second named rolls, means for withdrawing at least one of said elements to maintain a desired relationship between said rolls and thesurfaces of said mandrel plug while a pipe or tube is being acted .upon thereby, a speed-adjuster for said means,

means responsive to the temperature of said pipe or tube for controlling said speed-adjuster, and means for returning the withdrawn element'to its initial position. 1

STEVENSON FINDLATER.