US3209452A

US3209452A - Method of producing bars or sections by continuous casting

Info

Publication number: US3209452A
Application number: US191850A
Authority: US
Inventors: Schneckenburger Emil
Original assignee: MOOSSCHE EISENWERKE AG
Current assignee: AG DER VON MOOS'SCHEN EISENWERKE; MOOSSCHE EISENWERKE AG
Priority date: 1961-05-05
Filing date: 1962-05-02
Publication date: 1965-10-05
Anticipated expiration: 1982-10-05
Also published as: BE617234A; DE1433023A1; NL278138A; GB967281A; CH423105A

Description

Oct. 5, 1965 E. SCHNECKENBURGER 3,209,452

METHOD OF PRODUCING BARS OR SECTIONS BY CONTINUOUS CASTING Filed May 2, 1962 2 Sheets-Sheet 1 dlllll II/ at l/lII/l/I United States Patent 3,209,452 METHOD OF PRODUCING BARS 0R SECTIONS BY CONTINUOUS CASTING Emil Schneckenburger, Emmenbrucke, Switzerland, assignor to Aktiengesellschaft der von Moosschen Eisenwerke, Ernrnenbrucke, Lucerne, Switzerland Filed May 2, 1962, Ser. No. 191,850 Claims priority, application Germany, May 5, 1961, A 37,366 7 Claims. (Cl. 29-528) This invention relates to a method of producing bars and sections by continuous casting. The conventional method of producing bars and sections by continuous casting consists in casting each bar separately in a continuous casting mould and in then cutting the bar at appropriate intervals to provide the required lengths. It has also been proposed to produce several bars simultaneously in one machine in one mould. This method is known as the multiple mould continuous casting technique.

If it is desired to produce sections, then either the bars may be rolled down to the required sections or each section may be continuously cast independently of the other, but in practice this gives rise to considerable difiiculties. Particularly in multiple mould continuous casting machines trouble often arises because it is diflicult to maintain exactly similar conditions in each continuous casting.

One difiiculty which arises in multiple mould continuous casting machines is that of ensuring a satisfactory distribution of the melt. In order to prevent the melt from solidifying in the distributor and also to avoid absorption of oxygen it is usually the aim to feed the melt into the mould along the shortest possible path. This means that the several castings must be withdrawn from the mould in closely adjacent juxtaposition. Difiiculties then arise in locating the withdrawing means. It is impossible to provide separate withdrawing means for each continuous casting. It had thus been proposed to provide driving roller of adequate length to withdraw several castings simultaneously side by side. However, it has been found that diiferential wear of the driving rollers impairs contact between rollers and metal and that this leads to irregular withdrawal of the several castings. Subsequent readjustment of the rollers is impossible if there are three or more castings so that this proposal is not generally used in machines delivering more than two castings.

The object envisaged by the present invention is the simultaneous production of several bars by continuous casting without incurring the troubles due to the difiiculty of uniformly feeding the metal into the multiple mould and of withdrawing the several castings from the mould. The invention also proposes to provide the means for producing sections by a particularly convenient and advantageous method of manufacture without the necessity of first producing a bar as an intermediate product.

To this end the invention consists in first producing rectangular or substantially rectangular flat or grooved slabs by continuous casting and in then further deforming the slabs in continuous operation, dividing them into a plurality of continuous sections or bars. Deformation and division into several bars or sections is preferably done by rolling the slabs between grooved rolls.

Preferably therolled material may be elongated Without spreading by being rolled down in grooved rolls forming closed passes.

In order to overcome the difiiculties which arise when feeding the leading end of the continuous casting into the rolls it is preferred not to set the rolls and not to close the passes until the leading end of the casting has been gripped by the rolls. The diameter of the rolls need not then be excessively large.

The proposed method permits finished bars or sections to be produced in only one or only a few passes. Conventional methods of rolling would require a fairly large number of passes.

If the necessary deformation cannot be achieved with a single pair of rolls, rolling may be in stages in several consecutive roll stands each fitted with rolls having progressively sharper ridges between the grooves.

The rolled material issuing from the shaping rolling mill or from the final roll stand may be divided into completely separate bars or sections by conventional cutting means, such as cutting rolls, circular shears, reciprocating shears, cutting discs, brake cutting devices or breaking machines, the bars or sections still being connected together by a fairly thick flash when they issue from the final pair of grooved shaping rolls.

The invention also relates to special contrivances and apparatus for performing the method according to the invention.

The invention will now be more particularly described by reference to the accompanying drawings.

In the drawings:

FIG. 1 schematically illustrates a continuous casting plant comprising a permanent mould for producing a grooved continuous casting, a guideway which for the sake of simplicity is shown as consisting of cylindrical rollers and at the end of the guideway a pair of grooved rolls;

FIG. 2 illustrates a pair of grooved rolls for rolling bars, seen in the direction of rolling;

FIG. 3 similarly shows a pair of rolls for rolling angle sections; and

FIG. 4 illustrates the use of a grooved backing roll.

A conventional metal feeding means is indicated at 1. In the illustrated embodiment this is assumed to be an ordinary teeming ladle which charges the liquid metal into a shaped permanent continuous casting mould. A continuous casting 3a which already possesses a solidified outer skin emerges from the mould 2 and is further guided between rollers 4 which gradually turn the casting from the vertical into the horizontal direction. All the rollers 4 are driven by a common drive means not specially shown in the drawing. Endwise location of the continuous casting 3a is effected by lateral guide rollers 5. 6 are spraying nozzles which spray a coolant on to the continuous metal casting 3a and on to the guide rollers 4. After having passed through a roller straightening machine the continuous casting passes through several sets of grooved rolls of which only one pair 7 is shown in the drawing.

The illustrated plant functions as follows:

The continuous casting 3a which already possesses a solidified skin as it issues from the permanent mould 2 is guided between the driven guide rollers 4 which gently turn the casting into the horizontal direction. The coolant sprayed from the nozzles 6 causes the casting 3a which is deeply grooved because of the particular shape of the mould, to solidify completely. Having travelled through a straightening machine not shown in the drawing the continuous casting 3a passes through one or more pairs of grooved rolls, the final set of grooved rolls having a cutting action and longitudinally separating the deeply grooved continuous casting into adjacent separate bars which are finally cut to suitable lengths by a cross cutting device,

The straightening machine may of course be located at some other point than that specified in the foregoing description.

Alternatively, the longitudinal division of the deeply grooved continuous casting may be effected by cutting means of some other known kind, such as circular cutting sears, reciprocating shears, oxyacetylene cutters or breaking machines which then take the place of the cutting rolls.

It is also within the scope of the present invention to replace the grooved permanent mould which produces a preshaped continuous casting by a mould of conventional rectangular section, the narrow sides having any desired conformation, for instance a circular shape. A continuous casting which is not already grooved may be divided in various ways, for instance by grooving the casting by a pass through grooved rolls followed by cutting rolls or by any of the above mentioned cutting devices to effect the final longitudinal separation of the casting into several bars, or the continuous cast slab may be divided by known cutting means including oxyacetylene cutting without previous rolling. Moreover, the continuous casting, irrespectively as to whether this has been preshaped in the mould or whether it issues from the mould as a flat slab need not be turned from the vertical into the horizontal before division takes place. The rolling of the divided slab can then proceed at a higher rate.

FIG. 2 illustrates a grooved pair of rolls for rolling wire bars of section 10. The bottom roll 11 has flanges 12 which embrace the sides of the upper roll 13. The openings or passes are closed so that the rolled material cannot spread sideways. The prevention of lateral spread is even more effectively achieved between rolls shaped as shown in FIG. 3, where the flange 12a of the bottom roll 11 directly defines the outside pass 14 for the production of a plurality of angle sections. The slab from which four angle sections 15 are rolled enters between the two flanges 12a and is therefore prevented from laterally spreading. Only elongational deformation is possible. The faces 16 of the flanges 12a contacting the sides of the top roll 17 completely close the passes 14.

Since the necessary roll pressure is rather high the provision of backing rolls may be advisable. This is further illustrated in FIG. 4 where a working roll 21 with grooves 22 is supported by a backing roll 23. The backing roll 23 bears only on the faces marked 24 of the working roll. These are faces which are not subjected to the severest stresses when rolling. The ridges 25 between the grooves of roll 21 are not exposed to the backing pressure because they freely project into recesses 24 in the backing roll.

What I claim:

1. A method of producing bars and sections by continuous casting, said method comprising the steps of feeding molten metal into a mold comprising a mold chamber having an input end, freezing zone and withdrawing end, said ends having slab-like and slightly indented cross section, withdrawing a strand from this mold, guiding said strand issuing from said mold in a desired path, cooling the strand in said path to complete solidification and to provide a desired hot-working temperature, straightening said strand, guiding the leading end of the strand between spaced grooved rolls, closing and setting said rolls and hot-working said strand in continuous operation to divide said strand into a plurality of laterally adjacent bars or sections of desired cross section.

2. Apparatus for producing bars and sections by continuous casting, said apparatus comprising a cooled flowthrough mold of substantially constant and slightly indented cross section, said cross section being such as to form a cast strand of slab-like cross section provided with shallow longitudinal indentations, a plurality of guide rollers defining a desired path beginning adjacent to said mold for guiding said strand issuing from said mold along said path, a plurality of coolant spraying means associated with said rollers and directed toward said path for spraying a cooling fluid on said strand, means for straightening said strand, at least one roll stand, at least one roll of said roll stand being formed with circumferential grooves corresponding in number and position to the indented parts of said mold cross section for hot-working the strand into bars and sections.

3. Apparatus for producing bars and sections by continuous casting, said apparatus comprising a cooled flowthrough mold of substantially constant and slightly intended cross section, said cross section being such as to form a cast strand of slab-like cross section provided with shallow longitudinal indentations, a plurality of guide rollers defining a desired path beginning adjacent to said mold for guiding said strand issuing from said mold along said path, a plurality of coolant spraying means associated with said rollers and directed towards said path for spraying a cooling fluid on said strand, means for straightening said strand, a plurality of roll stands in said path of said strand, each stand having a pair of cooperating grooved rolls, which define a laterally closed pass, each successive pass being more constricted and having sharper projections, for hot-working the strand into bars and sections.

4. Apparatus for producing bars and sections by continuous casting, said apparatus comprising a cooled flowthrough mold of substantially constant cross section, said cross section being such as to form a cast strand of slablike cross section provided with shallow longitudinal indentations, a plurality of driven guide rollers defining a desired path beginning adjacent to said mold for guiding said strand issuing from said mold along said path, a plurality of coolant spraying means associated with said rollers and directed toward said path for spraying a cooling fluid on said strand and rollers, a plurality of roll stands in the path of the strand, each stand having a pair of cooperating rolls of which at least one is formed with circumferential projections corresponding in number and position to said indentations, each stand defining a laterally closed pass, each successive pass being more constricted and having sharper projections, whereby said strand will be formed into a plurality of laterally adjacent bars or sections of desired cross section and means for straightening said strand.

5. Apparatus according to claim 4, wherein said mold is substantially vertical and said path is a curve extending from said mold and having a substantially horizontal termination, said straightening means being disposed adjacent to said termination and preceding said roll stands.

6. Apparatus according to claim 4, wherein one roll of a stand has radial end flanges embracing the ends of the co-operating roll, and wherein each roll is backed by a grooved backing roll bearing only on parts of the roll that are not highly stressed during rolling.

7. Apparatus for producing bars and sections by continuous casting, comprising a cooled flow-through mold of substantially constant and slightly indented cross section, said cross section being such as to form a cast strand of slab-like cross section, provided with a shallow longitudinal indentation, a plurality of guide rollers defining a desired path beginning adjacent to said mold for guiding said strand issuing from said mold along said path, a plurality of coolant spraying means associated with said rollers and directed toward said path for spraying a cooling fluid on said strand, means for straightening said strand, a plurality of roll stands in said path of said strand, each stand having a pair of cooperating grooved rolls which define a laterally closed pass, each successive pass being more constricted and having sharper projections,

5 6 whereby said strand will be hot-worked into a plurality 2,711,577 6/55 Leach 29-528 X of laterally adjacent bars or sections of desired cross sec- 2,947,025 8/60 Schneckenburger et a1. 29-528 X tion and cutting means succeeding said stands for longi- 2,975,493 3/61 Morton et a1. 22-572 X tudinally separating said bars or sections. 3,147,521 9/64 Boehm 29-528 X References Cited by the Examiner 5 OTHER REFERENCES UNITED STATES PATENTS Making, Shaping and Treating of Steel, U.S. Steel G eer C(L, 2 3331232 9??? 33 5;525:2211:ij'iilifif 10 WHITMORE WILTZ Primary 2,053,375 9/36 Nichglas, JOHN F. CAMPBELL, Examiner.

Claims

1. A METHOD OF PRODUCING BARS AND SECTIONS BY CONTINUOUS CASTING, SAID METHOD COMPRISING THE STEPS OF FEEDING MOLTEN METAL INTO A MOLD COMPRISING A MOLD CHAMBER HAVING AN INPUT END, FREEZING ZONE AND WITHDRAWING END, SAID ENDS HAVING SLAB-LIKE AND SLIGHTLY INDENTED CROSS SECTION, WITHDRAWING A STRAND FROM THIS MOLD, GUIDING SAID STRAND ISSUING FROM SAID MOLD IN A DESIRED PATH, COOLING THE STRAND IN SAID PATH TO COMPLETE SOLIDIFICATION AND TO PROVIDE A DESIRED HOT-WORKING TEMPERATURE, STRAIGHTENING SAID STRAND, GUIDING THE LEADING END OF THE STRAND BETWEEN SPACED GROOVED ROLLS, CLOSING AND SETTING SAID ROLLS AND HOT-WORKING SAID STRAND IN CONTINUOUS OPERATING TO DIVIDE SAID STRAND INTO A PLURALITY OF LATERALLY ADJACENT BARS OR SECTIONS OF DESIRED CROSS SECTION.