US3421572A

US3421572A - Continuous casting apparatus having independent transverse and longitudinal mold surface movement

Info

Publication number: US3421572A
Application number: US493373A
Authority: US
Inventors: Richard F Reihman
Original assignee: Bethlehem Steel Corp
Current assignee: Bethlehem Steel Corp
Priority date: 1965-10-06
Filing date: 1965-10-06
Publication date: 1969-01-14
Anticipated expiration: 1986-01-14

Description

Jan- 14, R. F' REIHNAN CONTINUOUS CASTING APPARATUS HAVING INDEPENDENT TRANSVERSE AND LONGITUDINAL MOLD SURFACE MOVEMENT Sheet of 5 Filed Oct. 6. 1965 INVENTOR Ric/lara /Fe//mlan Jan. 14, 1969 R F. REIHMAN 3,421,572

NG APPARATUS HAVING INDEPENDENT CONTINUOUS CASTI TRANSVERSE AND LONGITUDINAL MOLDv SURFACE MOVEMENT Sheet Filed Oct. 6. 1965 Ffy. i

INVENTOR Jan. 14, 1969 R' p REIHMAN 3,421,572

US CASTING APPARATUS HAVING INDEPENDENT ERSE AND LONGITUDINAL v MOLD SURFACE MOVEMENT CONTINUO TRANSV Filed Oct. 6, 1965 United States Patent O 6 Claims ABSTRACT OF THE DISCLOSURE An apparatus and method for applying compressive and shear forces to the surfaces of a continuous casting in an open-ended continuous casting mold. Selected portions of the mold are reciprocated toward and away from each other in a transverse direction at a predetermined cyclic rate while the entire mold is reciprocated independently and at a different cyclic rate in a longitudinal direction.

'Ihis invention relates to the continuous casting of metals and metal alloys and more particularly to an improved mold assembly and an improved method of moving a mold assembly in continuous casting apparatus.

Heretofore, many different types of apparatus and methods have been tried in order to cast molten metals and alloys in a single elongated casting rather than in a number of individual castings or ingots. At first, various forms of an open-ended stationary mold were tried. The major difficulty With such a mold was that the solidified metal casting tended to stick to the Walls of the mold making the withdrawal of the casting from the mold diflicult. This practice was also very slow and usually resulted in castings of poor surface quality. It was then suggested to reciprocate an open-ended mold in a direction parallel to the longitudinal axis of the casting, such as shown by U.S. Patent No. 1,385,595 to Van Ranst. This practice not only reduced the friction between the mold walls and the casting but also permitted casting `at a somewhat faster rate with improved surface quality.

It has yalso been suggested to use a vertically split open-ended mold in which the mold sections are vibrated at right angles to the longitudinal axis of the casting or oscillate about fixed points while keeping the mold stationary in a vertical direction. Generally, this practice was only suitable for casting at relatively slow rates.

It is therefore an object of my invention to provide continuous casting apparatus and a method of operating continuous casting apparatus which will enable one to cast molten metal and metal alloys at a relatively high rate of speed.

It is a further object of my invention to provide continuous casting apparatus and a method of using continuous casting apparatus which will produce metal castings having superior surface quality.

fIt is a still further object of my invention to provide an open-ended mold assembly for the continuous casting of metals and metal alloys which greatly reduces any tendency of the solidified metal casting to stick to the walls of the mold during the casting operation.

I have discovered the fore-going objects can be attained by using a longitudinally split open-ended w-atercooled mold which is reciprocated in a longitudinal direction while opposed sections of the mold are reciprocated toward and away from each other in a transverse direction simultaneously with but independent of the reciprocation of the mold in the longitudinal direction.

Referring to the drawings which illustrate an embodiment of my invention.

3,421,572 Patented Jan. 14, 1969 FIGURE l is a side elevation, partly in section, of continuous casting apparatus embodying my invention.

FIGURE 2 is a sectional view taken along line 2 2 of FIGURE l.

FIGURE 3 is a top view, partly in section, of the mold assembly.

FIGURE 4 is a sectional view of the mold assembly taken yalong line 4-4 of FIGURE 3.

As shown in FIGURE 1, vertical structural columns 1 support a horizontal working platform 2 above the level of the shop floor 3. Rigidly attached to the working platform 2 is a rectangular structural frame 4 comprised of vertical structural columns 5 and horizontal girders 6. Structural frame 4 supports a tundish 7, a mold housing 8 and the various drive means required to reciprocate the mold housing 8 and the mold 9.

Molten metal from a ladle or holding furnace (not shown) is poured into tundish 7 from which the molten metal is then introduced into the top of an elongated cavity of an open-ended, water-cooled mold 9, where the molten metal is cooled until an elongated metal casting 10 having a solid exterior and a molten interior is formed. The partially solidified casting 10 is withdrawn from the bottom of the mold cavity and is guided into a cooling chamber 11 where high pressure jets of water 12 spray the surface of the vcasting 10, cooling it further. Opposed pairs of guide rolls 13 contact the sides of the casting and guide the casting through the cooling chamber 11. Immediately below the cooling chamber 11 is one or more pairs of driven pinch rolls 14 which control the speed of withdrawal of the casting. The casting 10 is then either deliected to a horizontal direction or, as shown in FIGURE l, descends vertically to the shop lioor 3 where it is cut off into suitable lengths by cutting torches or the like (not shown).

As best illustrated in FIGURES l and 2, the mold housing 8 is suspended within the rectangular structural frame 4 by trunnions 16. The trunnions are attached to a pair of parallel arms 17 journaled at one end to the end of a shaft 18 attached to columns 5 of structural frame 4. The other ends of arms 17 are joined by a cross-member 19. The arms 17 are thereby free to pivot about shaft 18 in parallel vertical planes. Directly under the midpoint of cross member 19 Iare a 4hydraulic piston and cylinder 20 connected to a hydraulic pump and valve arrangement, not shown. It will be evident that raising and lowering of the piston in hydraulic cylinder 20 will cause arms 17 to pivot about shaft 18 and in turn reciprocate mold housing 8 in a longitudin-al direction parallel to the longitudinal axis of the casting 10. This results in a shearing force parallel to the longitudinal axis of the casting being appplied to the surface of the casting 10.

As shown in FIGURES 3 and 4, the mold 9 is set within the mold housing 8 and has its side walls split longitudinally along lines parallel to the longitudinal axis of the castinlg into pairs of opposed wall sections 21. Sections 21 are hollow and water-cooled and preferably rnade of copper. While I have Iillustrated the mold 9 in FIGURE 3 as comprised of four wall sections of equal size for casting a square billet, it is apparent that the mold 9 may be comprised of any even member of sections of any required dimension.

Each mold section 21 is attached to the mold housing 8 by flexible support members 22 attached both to the to-p and bottom of the rear faces of Wall sect-ions 21 as shown in FIGURE 4.

Also set Within the Imold housing 8 but surrounding the mold 9 is mechanical means for reciprocating a pair or pairs of opposed wall sections 21 toward and a-way from each other in a transverse direction simultaneously with but `independent of the reciprocation of the mold 9 and mold housing 8 in the longitudinal direction.

This mechanical means includes for each wall section of the pair, a drive shaft 23 journaled on the mold housing 8 by suitable bearings 24, an eccentric 25 mounted on each of the drive shafts 23 and a connecting rod 35 connecting the eccentric 25 to the rear face of the respective wall section 21 approximately midway between the top and bottom flexible support members 22. As seen best in FIGURE 3 the drive shafts 23 all lie in a `common plane which is perpendicular to the longitudinal axis of casting 10. Drive shafts 23 are joined to one another by bevel gears 26 positioned at the corners of mold housing 8 and are driven at the same speed by shaft 27 driven by electric motor 28 through a jackshaft 29, sheaves 30 and exible belts 31. Enough slack is maintained in the flexible belts 31 to permit the longitudinal reciprocation of the mold housing 8.

The eccentrics 25 convert the rotary motion of drive shafts 23 into a rectilinear motion in a direction transverse to the longitudinal axis of the casting. This motion is imparted to the wall sections 21 which results in a progressively increasing and then decreasing compressive force being applied to the casting perpendicular to the longitudinal axis of the casting. Eccentrics 25 can be designed with a suitable dwell time so that the compressive force is held at a maximum for a predetermined period of time against the surface of the casting before the force begins to decrease.

With the arrangement of wall sections 21 as shown in FIGURE 3, I prefer to so position the eccentrics on drive shafts 23 so that as one pair of opposed wall sections 21 are moving towards each other and against the casting in the transverse direction, the other pair of opposed wall sections 21 are moving away from each other and the casting also in the transverse direction. For casting large rectangular slabs, it may be preferable for the wall sections 21 defining the narrow e-nds of the slab to move not at all. 'This may be done by replacing the respective eccentrics with circular bushings or by removing the respective connecting rods 35.

As a result of the apparatus and methods of my invention, it is possible to continuously cast metal castings of superior surface quality at rates higher than has heretofore been possible.

AS an example of my invention I have designed apparatus for casting a 2 x 2" square billet in which the mold is reciprocated in the longitudinal direction at a cyclic rate of less than 300 cycles per minute with the upstroke being at a speed yat least twice as fast as the downstroke. The length of the longitudinal stroke is between 3A" and 11/2. The opposed -wall sections are reciprocated toward and away from each other in the transverse direction at a cyclic rate -of 300-1700 cycles per minute and preferably at a cyclic rate approximately twice that of the longitudinal reciprocation. The length of the stroke in the transverse direction is 0.020 inches.

As m-any possible embodiments may be Lmade of rny invention without departing from the scope thereof, it is to be understood that all matter set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. Apparatus for producing an elongated metal casting comprising a housing, a water-cooled open-ended mold set within said housing and having side walls split longitudinally along lines parallel to the longitudinal axis of the casting into pairs of opposed wall sections, means for reciprocating said housing and said mold in a longitudinal direction and a separate ymeans for reciprocating at least one pair of opposed wall Sections toward and away from each other in a transverse direction simultaneously with but independent of and at a different cyclic rate than the reciprocation of said housing and said mold in the longitudinal direction.

2. The apparatus of claim lwherein the pairs of opposed wall sections are two in number.

3. .The apparatus of claim 1 wherein one pair of opposed wall sections remain stationary lin the transverse direction.

`4. Apparatus for producing an elongated metal casting comprising a housing, a Water-cooled open-ended mold set within said housing and having side walls split longitudinally along lines parallel to the longitudinal axis of the casting into pairs of opposed wall sections, hydraulic means for reciprocating said housing and said mold in a longitudinal direction and mechanical means for sim-ultaneo-usly reciprocating at least one pair of opposed wall sections toward and away from each other in a transverse direction simultaneously with but independent of and at a different cyclic rate than the reciprocation of said housing and said mold in the longitudinal direction.

5. Apparaus for producing an elongated metal casting ycomprising a housing, a water-cooled open-ended mold set within said housing and having side walls split longitudinally along lines parallel to the longitudinal axis of the casting into pairs of opposed wall sections, exible support members connecting the top and bottom of each mold section to said housing, means for reciprocating said housing and said mold in a longitudinal direction and independent means for simultaneously reciprocating at least one pair of opposed wall sections toward and away from each other in a transverse direction, said independent means including, for each of said mold sections in said pair, a rotating shaft mounted on said housing, an eccentric mounted on said rotating shaft for converting rotary motion to rectilinear motion in a transverse direction and a connecting rod connecting said eccentric to said mold section approximately midway between the top and the bottom flexible support members.

6. Apparatus for producing an elongated metal casting comprising a housing, a water-cooled open-ended mold set within said housing and having side walls split longitudinally along lines parallel to the longitudinal axis of the casting into pairs of opposed wall sections, exible support members connecting the top and bottom of each mold section to said housing, hydraulic means for reciprocating said housing and said mold in a longitudinal direction and mechanical means for simultaneously reciprocating at least one pair of opposed wall sections toward and away from each other in a transverse direction, said mechanical means including, for each of said mold sections in said pair, a rotating shaft mounted on said housing with its longitudinal axis lying in a plane perpendicular to the longitudinal axis of said casting, an eccentric mounted on said rotating shaft for converting rotary motion to rectilinear motion in a transverse direction and a connecting rod connecting said eccentric to said mold section approximately midway between the top and bottom exible support members.

References Cited UNITED STATES PATENTS 2,135,183 11/1938 Junghans 164-83 2,284,703 6/ 1942 Welblund et al. 164-83 2,698,978 1/1955 Welblund 164-83 3,075,264 l/1963 Wagnum 164-83 3,118,195 1/1964 Gouzou et al. 164-83 3,208,112 9/1965 Scribner 164-83 2,262,208 11/1941 Shepard 164-274 J. SPENCER OVERHOLSER, Primary Examiner.

R. SPENCER ANNEAR, Assistant Examiner.

U.S. C1. XR.