US1718806A

US1718806A - Rolling of band iron, hoops, and the like

Info

Publication number: US1718806A
Application number: US184806A
Authority: US
Inventors: Witting Bruno
Original assignee: Individual
Current assignee: Individual
Priority date: 1926-04-23
Filing date: 1927-04-18
Publication date: 1929-06-25
Anticipated expiration: 1946-06-25
Also published as: BE341159A; DE481741C; FR633077A

Description

June 25, 1929. B. WITTING I Y 1,718806- ROLLING OF BAND IRON, HOOPS, AND THE LIKE Filed April- 18, 1927 2 Sheets-Sheet 1 lmmmun p IIIIHIWIIIIIIIWIH June 25, 1929. wlTTlNG 7 1,718,806

ROLLING of BAND IRON, Hoors, AND THE LIKE Filed A ril' 18, 1927 2 Sheets-Sheet 2 o '0 0 DE 4 Q0 w 0 Q Inventor:

Patented June-25,1929.

PATN OFFIC BRUNO WITTING, OF BON'N-ON-THE-RHINE, GERMANY.

ROLLING F BAND IRON, HOOPS, AND THE LIKE.

Application filed April 18, 1927, Serial No. 184,806, and in Germany April 23, 1928.

This invention has reference to rolling means and it refers in particular to improvements in the rolling of band-iron, hoops and the like, either of plain or of profilated or '5 figured cross section, and is likewise adaptable to the rolling of metal bands and of similar material of plain and or profilated cross section or other metals but iron, and it is intended toincrease the facility of manipulation and the output of the product, and to generally improve the manufacturing process. The manufacture of band-iron or hoop-iron and of steel bands of a thickness of 1 millimeters (0.06 inches) and less has been effected heretofore generally in such a manner that the billets which have been preliminarily rolled in hot-rolling devices to a thickness of 1% millimeters and above were then rolled down to the required thickness in cold condition and in special rolling machines. The rolling operation was effected in several stages in accordance with the thickness required but in such a manner that the reduction of thickness of the cold rolled material at each stage was only a comparatively small one. The brittleness and hardness of the material to be rolled has to be overcome by the repeated burning or annealing of the rolled band of material in special annealing ovens, such annealing stages being inserted between the several rolling stages. This manner of procedure which admits of obtaining only limited outputs, might be greatly improved and rendered more economical, if it would be possible to roll down the band of unfinished material produced in the rolling machine to a thickness of less than only 1% millimeters, in order to thereby decrease the working profile of the cold rolling machines. This manner of operation is however interfered with by the rapid drop of temperature 0btainod in the rolling of iron bands, so that the further reduction of thickness has heretofore been entirely leftto the treatment of the iron band obtained in the warm condition by the subsequent action of the cold rolling machines. In accordance with the previous methods it has been suggested to heat again the band-shaped material fed to the cold rolling devices and previously obtained in the hot condition, special devices and furnaces being provided for the re-heating of the material before its introduction to the cold rolling machines, but the results obas tamed are unsatisfactory, because there is either a very rapid overheating of the iron band on account of the direct action of the heat concentrated upon a particular point, or the heating of the material was lackin ea in uniformity, so as to obviate the desire purpose.

In accordance with this invention these drawbacks are overcome by providing fora heating by electrical means and in such a manner that the rolling goods to be heated are traversed by the electrical or ,the magnetlc current. Provision may be made to admit the current to the rolling goods by induction or bg means of electric contacts, and preferably t e admission of the current may be effected in several, I serially arranged length of the rolled goods. In this connection provision ma be made to regulate and adjust the strengt of the current in eachof these several lengths. The regulation .3 be preferably efiected in such a mannerthat the rolling goods under treatment are heated to the rolling temperature only shortly in front of the rolling device. is regulation may be efiected manually or automatieally and dependin upon the temperature of the heated rolle goods. A particu. larly advantageous arrangement will be obtained by causing the current to pass through the rolled material in the longitudinal direction thereof.

The admission of the current ma for instance be eflected by the tapping o the secondary coil of a transformer at repeated to points, so that from the tapped portions heating currents of difi'erent strengths and preferably of a strength decreasing in the direction of the rolling operation may be fed to the different lengths of the rolled material as disposed between the respective pairs of electrodes.

The admission of the current in this case is efiected by means of electrodes distributed along the length of rolled material to be heated, such electrodes being preferably constructed as roller electrodes which are employed together with the pressure rollers. In order to insure the uniform pressure con tact of these rollers one of the rollers of each we pair of rollers or rolls ma be conducted in inclined guides with relatlon to the general direction of the passage of the material, so

limited by means of adjustable stops. It is advantageous in this connection to impart figured or profilated cross sections to the rollers, that is to say to provide them with ribs, flutings or with point-ed sections, so as to insure the highest possible uniformity of the admission .7 of the current and the greatest intensity thereof.

Instead of arranging the material to be rolled so as'to become part of one or several secondary circuits of a transformer, the heatin and annealing-of the material to be ro led may also be effected by means of eddy currents produced by high frequency alternating currents. The generation of the eddy current is preferably eifected in air transformers without iron cores. As an exemplification a mufile of refractory material may be disposed between two roller scaflolds of usual construction, around which a coil of conducting material and fed with high frequency alternating current is substantially concentrically arranged the field of force of which causes the heating to the glowing temperature of the material to be rolled and introduced intothe interior of the mufll'e and kept continuously in motion,

so that this material is easily raised to the rolling temperature.

The invention will be more particularly described by reference to the accompanying drawing showing by way of illustration and exemplification two forms of embodiment of the. principles of this invention. In the drawings Fig. 1 is a diagram in front View of the arrangement of a rolling mill with heating means in front thereof; Fig. 2 is a diagram showing the electric connections of the circuit used for this purpose; Fig. 3 is another diagram of the general arrangement of the circuit; Fig. illustrates an electrode for the admission of the current to the material to be rolled and having the general shape of a profilated roller; Fig. 5 illustrates a preferred way of mounting the roller elec-' trode; Fig. dis a side View showing diagrammatically a device for effecting the heating of the goods to be rolled by means of'eddy currents; Fig; 7 is a diagram illustrating a device for the automatic control of the current strength; Fig. 8 shows diagrammatically an embodiment of means for the automatic regulation of the current and of the temperature produced.

In accordance with the arrangement shown in Figures 1 and 2 by way of illustration a cold rolling machine a ofwellknown construction is combined with a heating apparatus disposed in front thereof with relation to the passage of the material. Both devices may be supported each on a separate base or they may be combined in any suitable manner, so as to constitute a unitary whole. By means of this heating apparatus the otherwise well-known procedure is most advantageously carried out according to which a piece of work of iron or other metal of a certain cross section and introduced between the two terminals of a dynamo machine is immediately heated upon the switching into circuit of the electric current.

The mode of operation of the heating apparatus, as appears from the diagram of Fig. 2, is substantially as follows: Through the primary winding h an electric current of ordinary voltage is caused to flow which in the secondary winding 0 induces a current of low voltage but of high intensity which latter current is conducted to the terminals e and 7 which for the purposes of the invention constitute roller electrodes. The current traverses the iron band 9 which is forced by the. pressure. rollers d against the electrodes and constitutes the shortest way between the terminals 6 and f, and by this the particular degrees of temperature which may be adjusted by special regulating and controlling means.

In order to spread. the heating along a greater extent of the material to be rolled, so as to prevent unnecessary strains on the material, a plurality of pairs of electrodes serving for the admission and the discharge of the current are serially arranged and are fed by separate sources of current, such as for instance transformers; the band of iron 9' (Figures 1 and 2) on its way from the reel or the like, not shown, to the rolling machine a passes successively through the pairs of electrodes under the action of the pressure rollersd. The iron band which, so to speak, has been pro-heated between the first pair of electrodes 6 is-made to pass on to the next and higher heating zone and thus in succession, until the band between the .rolling method according to this invention which presents the additional advantage of doing away with the necessity of burning the rolled iron band between the several stages the method according to this invention pic I sents the great advantage of maintaining the heating apparatus continuously in proper operating condition, so as to produce sharply defined temperatures in the several heating zones, while on the other hand the blistering of the iron band and consequently the formation of cinders and slags are excluded. 'The process may also be applied with great commercial success for the rolling out of certain predetermined profilated shapes of iron from band iron or fiat iron, thus for instance of slotted tubes in which case the skelp before the introduction into the calibrated rollers is submitted to a gradual heating to the rolling temperature required for the ready moulding of the material.

The pos ibility of maintaining certain sharply defined temperatures renders the invention particularly adapted for the finishing rolling of bands, profiles, channel irons, pipes or the like from other metals but iron in the working of which the success of the treatment would be annihilated by the exceeding of the critical rolling temperatures. The absolutely uniform heating of the unfinished metallic piece of work, the facility and reliability of the regulation of the temperatures in accordance with the method of the invention obviate the liability of any injurious overheating of the metals to be submitted to the further treatment.

The method of admitting the current to the materialto be rolled, as exemplified diagrammatically in Fig. 3 of the drawing has been shown to be particularly advantageous in the practical operation of the process.

In Fi 3 2' indicates the secondary coil of a trans ormer the primary coil of which is not indicated, in order to avoidcomplication. The secondary coil 71 is tapped at is, Z

and at m and. n. The end is of this second-' ary coil 71 is connected to the contact roller 0 and the other end n of the secondary coil z' is connected to the contact roller 0 and the band to be heated is moved in the direction of rollers 0 0 the roller 0 being arranged directly in front of the finishing rolling device. The secondary coil 6 is also tapped at Z and m and the tapped shunts are cono 0 0 0 bear the ratio 6:3:1, so that for instance 9 kw. is fed to the length 0 0 while 4, 5 kw. is admitted to the section o 0 and 1, 5 kw. is admitted to the section o,,0 This object may for instance be accomplished by admitti'ngGOO amps. current each to the contacts 0 0 and 0 so that through the contact 0 a total contact of 3 times 600=1800 amps. is caused to flow to the secondary. coil.

while the section 0 0 is traversed by a current of twice 600=1200 amps. and the section 0 0 by a current of 3 times 600=1800 amps; Considering the voltages necessary forthe production of the current strength mentioned this arrangement will result in the distribution of energy to the several sections hereinbefore indicated. 7

By means of this method of the admission:

In this case the section 0 0 is traversed by a current of 600 amps,

The electrode employed for the admission, of the electric current as indicated diagrammatically in Figures 1 and 3 of [the In order to arrive at a perfect and complete saturation of the drawing may be in the shape of ordinary smooth rollers or rolls.

surfaces of the material to be heated and to be rolled with the amounts of energy fed thereto, and to obtain the uniform conversion of these amounts of energy trodes admitting the current, as shown by way of example inFigure 4 of the drawing, may have theirouter surface suitably into heat in the rolling goods the elecprofilated or provided with blade-like projections p, as shown in Fig. 4 of the drawing, or with pointed parts, in order to produce the crowding of the amounts of electricity admitted in the transmission of the current. The profilated portions may be of straight or undular configuration or may assume any other suitable shape. In order to relieve the heated section of rolling material as much as possible from mechanical strain an additional rolling scaffold g'may be disposed infront of the electrodes 0. as indicated in Fig. 5, by meansof which the rolled material is admitted to the main rolling scafiold a at the required rate, so that neither a tensional strain nor a pressure will be produced between the two rolling scaffolds in the rolled material.

In order to obviate the liability of interruptions in the distribution of the current by deficient or changing formations of the points of contact, care should be taken to insure permanently good formation of contact, and in view of this object the arrangementshown diagrammatically in Figure (3 of the drawing may be used. Intlus ligure:-o and s are the two bearing sockets of a pair of contact-rollers or rolls. The

socket bearing 8 is arranged in the journal body t, so as to be displaceablein the direction of the arrow u, and its displacement is limited, by the screw '0. The adjustment of the socket bearing .9 by means of the screw 'v a is effected in such a manner that the center 411 of the upper bearing socket 8 is somewhat staggered with relation to the center w of the lower bearing 1', and in the direction of the passage of the metal band as. This direction of the passage of the material is indicated by the arrow 3 If the metal band is moving in the direction of the arrow, it will carry the upper roller which will, of course, first assume such a position that its center axis is disposed vertically above the center axis of the lower roller along with it in the direction of its path. By means of the upper inclination of the bearing socket this tendency will cause the roller beingmore firmly forced against the band passing between the rollers. This movement of the upper roller is terminated, as soon as the shaft of this roller or roll becomes engaged with the semi-circular bearing surface of the socket 8. By the adjustment of the bearing socket s by means of the screw '0 the contacting pressure may be regulated and stoppage and pinching of the band is prevented.

The screw, instead of operating upon the bearing socket smay of course be made to act directly upon the shaft of the roller. It should be understood that this manner of adjustment is provided .at both ends ofthe roller.

In further pursuance of my invention means are provided to carry out the method of the invention without the use of sliding or roller contacts, as particularly indicated diagrammatically in Fig. 7 of the drawing. In this figure the operating rollers are genorally indicated by the letters A .and A while B and B are the conveying rollers. By means of thcse rollers B and B the material S to be rolled is conducted through the heating mufile M to the pressure rollers A and A The heating muflle M which may consist of refractory clay or similar material is surrounded by the high frequency coil P At the rear of the working rollers A and A another muffle M is arranged in which the material which has been formed by the pressure rollers is subjected to an annealing process, in order to eliminate the brittleness and the other changes of physical qualities -of the rolled material occurrlng during the rolling operation. The muflie M is likewise surrounded by a concentrically disposed coil P5 which may. either be serially connected to the coil P or which, if desired, may also be fed from the high frequency line circuit, and if desired, by the admission of alternatmg'currents of different voltage intensity or number of periods in accordance with the particular nature of the piece of work to be heated.

In the practice of this invention it has been found to be particularly advantageous, -to feed the coils with high frequency alternating currents which in aceordance'with the size of the material .to be rolled may be worked at a frequency up to ten thousand periods per second and above. The coils material introduced into the interior of the mufile and which is kept continuously moving, to be heated to the glowing temperature and consequently to the proper temperature for the rolling operation. In this arrangement the coupling of the primary and secondary alternating currents by means of a closed iron core is avoided and the transformer is of the type of an air transformer without iron core.

In the method according to this invention it is of particular importance to adhere to certain definite temperatures of the material to be rolled, in order to avoid damaging thereof by overheating or to prevent irregularities in the process as a result of irregular heating. By controlling the admission of the current and consequently the heating by hand this uniformity of operation cannot be fully accomplished. It is therefore preferable to effect this regulation automatically and dependent upon the temperature of the rolled material. This automatic regulation is particularly of importance in view of the fact that fractions of seconds are sufficient for the overheating of the heated metal which has been heated forinstance to bright red heat, by the admission of too strong a current. A preferred way of the automatic regulation of the heating operation is shown for instance in Fig. 8 of the drawing.

In this figure, l is a selenium cell upon which by means of a lens 2 the light of the glowing color of the metal 3 to be heated is projected. The source of current feeds the two circuits 4 and 4 The circuit 4,, contains the electromagnet 5 and the circuit 4., contains the electromagnet 5 In the interior of the electromagnets 5 and 5 the iron cores 6 and 6 are respectively arranged which are suspended from the ends of a chain 8 passing by way of the sprocket rollers 7 and 7,,. Intermediate these rollers 7.l and 7 the contact race 9 is provided at the contacts of which tapped branch conduits of a regulating and controlling transformer not shown in the drawing are caused to terminate. Along the contact race 9 the contact slide 10 which is secured to the chai 8 is adapted to slide.

The selenium cell 1 is included in the circuit 4 of the electromagnet 5,, while in the circuit 4., of the electromagnet 5 a manually adjustable resistance 11 is included.

The mode of operation of this part of out of the method the device for the carrying u f 1 stantla y as 0 of this invention is su lows: 4

By the adjustment of the selenium cell 1 or by the adjustment of the resistance 11 the device will be set in such a manner that at a certain color of the hot glowing material, thus for instance at bright red heat, the two electromagnets 5 and 5,, will counterbalance each other. As soon as by more than the nornormal heating of the metal the irradiation of the selenium cell 1 becomes more intense the conductivity of said cell is increased, so that a stronger current will flow through the circuit 4 and as a result thereof the force of the electromagnet 5 will exceed the force of the electromagnet 5 In view thereof the chain 8 and in accordance therewith the contact 10 are displaced and by this means a certain amount of convolutions of the secondary coil of a transformer which furnishes the heating current are cut out, if as an instance a number of tapped conduits of a transformer, say nine of such conduits, are connected to the contacts of the contact race as above set forth, and it becomes pos-.

sible thereby to reduce the heating current. On the other hand, if as'a result of changing conditions the degree of heating pf the heated metal becomes reduced, the resistance of the selenium cell 1 irradiated by means of the lens 2 is increased, so that the current flowing through the coil of the electromagnet 5 is reduced. In this case the force of the electromagnet 5 will then exceed the force of the electromagnet 5 so that by means of the chain 8 the contact 10 is caused to move in the opposite direction, thereby including additional convolutions of the secondary coil of the transformer fur-- nishing the heating'current. By means of the device described it becomes possible to automatically cut in and out regulating and controlling resistances included in the heating current with similar advantage.

Instead of effecting the regulation by direct means, it may also be effected by the intermedia of relays.

These arid other modifications and alterations may be effected in carrying out the method according to this invention and in the building up of the apparatus for its most advantageous execution, and without thereby deviating from thescope and spirit of the invention as efined in the appended claims.

I claim a 1. The method of effecting the finishing rolling of substantially band-shaped and similar metallic material, which consists in first rolling the material substantially to the desired cross sectional shape, cooling it, then submitting it to the successive action of different amounts of electric energy, while keeping the material in motion, thereby gradually re-heating the material and finally submitting it to finlshing rolling.

2. The method of effecting the finishing rolling of substantially band-shaped and similar metallic material, which consists in first rolling the material to substantially the desired cross sectional shape, cooling it, and then submitting the material to movement in its axial direction and to gradual electric re-heating in successive stages of difierent electrical intensities, while in motion, and finally submitting it to finishing rolling.

3. The method of effecting the finishing rolling of substantially band-shaped and similar metallic material, which consists'in first rolling the material to substantially the desired, cross sectionalshape, moving it in the axial direction and submitting it-to the heating action of different intensities of electric alternating currents while in motion, anlrll after heating submitting it to finishing r0 mg.

4. The method of effecting the finishing rolling of substantially band-shaped and similar metallic material, which consists in first rolling the material to substantiall the desired cross sectional shape, allowing it to cool, moving it in the axial direction, inserting it in the secondary circuit of a transformer while in motion, and finally submitting it to finishing rolling.

5. The method of effecting the finishing rolling of substantially band-shaped and similar metallic material, which consists in first rolling the material to substantially the desired cross sectional shape, allowing it to cool, moving it in the axial direction and inserting it in the secondary circuit of a step-down alternating current transformer while in motion, and finally submitting it to finishing rolling.

6. The vmethod of efl'ecting the finishing rolling of substantially band-shaped and similar metallic material, which consists in first rolling the material to substantially the desired cross sectional shape, movin it in the axial direction, submitting it wl iile in motion to the action of high frequency electric currents, thereby producing eddy cur rents in such material and finally submitting it to finishing rolling.

7. The method of effecting the finishing rolling of substantially band-shaped and similar metallic material, which consists in first rolling the material to substantially thedesired cross sectional shape, allowing the material to cool, then gradually re-heating it by electric means, regulating the heat of each particular stage automatically in accordance with the heating color of such stage, and finally submitting the re-heated material to finishing rolling.

8. The method of effecting the finishing rolling of substantially band-shaped and similar metallic material, which consists in heating the material, rolling it substantially to. the desired cross sectional'shape, allowing it to cool, thenelectrically re-heating it in successive stages, projecting the heatcolor rays of the re-heated material onto selenium, including said selenium .in a heat regulating circuit and thereby regulatmg the re-heating of the material and finally submitting it to finishing rolling.

9.-The methodof effecting the finishing rolling of substantially band-shaped and similar metallic material, which consists in first rolling the material to substantially the desired cross sectional shape, allowing it to cool, moving it-in the axial direction through a field of surrounding high frequency currents, thereby re-heating the material, and

finally submitting itto finishing rolling. 10. The method of effecting the finishin rolling of substantially band-shaped an similar metallic material, which consists in first rolling the material to substantially the desired cross sectional shape, moving it in the axial direction and finally subjecting the material to finishing rolling and electrically 're-heating it' shortly before reaching the finishin stage.

11. T e method of effecting the finishin rolling of substantially band-shaped an similar metallic material, which consists in first rolling the material to substantially the desired cross sectional shape, moving it in the axial direction, allowing it to cool, and passing it in contact with spacedly disposed electric electrodes, including some of such electrodes in an electric circuit, tapping said circuit at certain adjustable points, connecting said points with the other electrodes in multiple connection, passing an electric current through said circuits and said multiple connection and finally submitting the thus re-heated material to finishing rolling.

12. The method of efiecting the finishin rolling of substantially band shaped an similar metallic material, which consists in desired cross sectional shape,-moving it in the axial direction and while in motion pass ing it in-contact with spacedly disposedi pairs of roller electrodes, each of said rollers being adapted to move in paths inclined to the travel of the band whereby upon the rollers being displaced by the movement of the traversing band a pressing of the rollers against the band is effected, passing an electric current through the electrodes and through the material and finally submitting the material to finishing rolling.

13. In a device of the character described in combination, preliminary rolling means and finishing rolling means spaced therefrom, a lurality of electric electrodes spacedly disposed intermediate the rolling means, an electric circuit on such electrodes, a controlling circuit connected to the other spacedly disposed electrical electrodes formaking contact with the material to be rolled comprising means cooperating with the electrodes and intermediate said rolling means and an electric circuitconnected to said electrodes. v

15. In a device of the character described in combination preliminary rolling means and finishing rolling means spaced from said preliminary rolling means, a plurality of pairs of superimposed roller electrodes spacedly disposed between the rolling means for making contact with the material to be rolled, inclined socket bearin s for supporting said roller electrodes, adjusting means on said inclined socket bearings, and an electric circuit connected to the electrodes.

16. In a device of the character described in combination preliminary rolling means and finishing rolling means spacedly dis posed from each other, a plurality of electrodes. spacedly disposed intermediate the rolling means, an electric circuit connected to said electrode, a contacting cir-. cuit cooperating therewith, a selenium cell in the controlling circuit adapted for 1 irradiation and responsive to the color of the in combination preliminary rolling means and finishing rolling means spacedly disposed from .each other for rolling band shaped and. similar material, conveying rollers spacedly disposed from the 'rolling means, electric heating means disposed be- 3 tween the conveying rollers and the rolling means, and heating coils surrounding said heating means.

18. The method of effecting the finishing rolling of substantially band-shaped and 2 similar metallic material, which consists in first rolling the material to substantially the desired cross sectional shape, moving it-in the axial direction and while inmotion passing it into contact with spacedly disposed I pairs of roller electrodes, each of said roller electrodes being adapted to move in paths inclined to the travel of the band and limited in travel by adjustable stops, whereby upon the rollers being displaced by the movement of the traversing band a pressing of the rollers against the band effected, passing an electric current through the electrodes and through the material and finally submitting the material to finishing rolling.

19. In a device of the character described in combination preliminary rolling means and finshing rolling means spaced from said preliminary rolling means, a plurality of 10 spacedly disposed electrical electrode rollers for making contact with the material to be rolled, said rollers having an outer periphery adapted to make a plurality of contacts, comprising means cooperating With the electrodes and intermediate said rolling means, and an electric circuit connected to said electrode. a

In testimony whereof I afiix my signature.

BRUNO WITTING.