US3689023A

US3689023A - Mold with tie rod assembly for slotted block

Info

Publication number: US3689023A
Application number: US133604A
Authority: US
Inventors: Richard Otis Peck
Original assignee: AMSTED RES LAB
Current assignee: AMSTED RES LAB
Priority date: 1971-04-13
Filing date: 1971-04-13
Publication date: 1972-09-05
Anticipated expiration: 1989-09-05
Also published as: SE387260B; CA958186A; DE2216489A1; JPS5136696B1

Abstract

In conjunction with a slab mold having spaced side blocks and a top, a bottom and end blocks engaged between the side blocks to define a casting cavity, an improved metallic end block is provided with a plurality of spaced, transverse slits. The end block is held in position relative to the other blocks by a supporting structure. A tie rod arrangement is secured to the upper and lower rearward portion of the end block to prevent vertical warping of the end block during the casting of a slab.

Description

United States Patent Peck [ Sept. 5, 1972 [54] MOLD WITH TIE ROD ASSEMBLY FOR SLOTTED BLOCK [72] Inventor: Richard Otis Peck, c/o Amsted Research Laboratory, 340 County Line Road, Bensenville, 111. 60106 22 Filed: April 13,1971

21 Appl.No.: 133,604

[52] US. Cl ..249/82 [51] Int. Cl. ..B22d 7/00 [58] Field of Search .249/82, 158; 164/342; 202/268;

248/DlG. 1

[56] References Cited UNITED STATES PATENTS 3,544,058 12/1970 Lohman ..249/l58X Primary Examiner-Robert D. Baldwin Attorney-Walter L. Schlegel, Jr. and John W. Yakimow [57] ABSTRACT In conjunction with a slab mold having spaced side blocks and a top, a bottom and end blocks engaged between the side blocks to define a casting cavity, an improved metallic end block is provided with a plurality of spaced, transverse slits. The end block is held in position relative to the other blocks by a supporting structure. A tie rod arrangement is secured to the upper and lower rearward portion of the end block to prevent vertical warping of the end block during th casting of a slab.

' 7 Claims, 3 Drawing Figures MOLD WITH TIE ROD ASSEMBLY FOR SLOTTED BLOCK BACKGROUND OF THE INVENTION This invention relates to mold construction and more particularly to a new and improved support arrangement for use in conjunction with a slab mold.

A basic mold structure particularly suitable for easting slabs of various sizes is described in U.S. Pat. No. 3,340,926. That mold structure includes a plurality of inner graphite blocks interengaged between a pair of graphite side blocks to define a casting cavity.

One of the difficulties encountered in the use of such molds is the fragile nature of the graphite. The blocks may be easily chipped or broken during assembly and disassembly of the mold. It was therefore suggested in U.S. Pat. No. 3,544,058 that at least one of these graphite blocks be replaced by a metallic block composed of a material such as cast iron or steel. For various reasons described within that patent, the block chosen was the bottom block. Since one portion of the bottom block is exposed to molten metal while the other portion remains relatively cool, The block has a tendency to distort. The distortion is caused by thermal expansion which results in the bowing up of the block at its ends or middle, thereby causing hot tears or other defects in the casting. The problem was corrected by providing means for limiting vertical warpage of the bottom block while permitting longitudinal expansion.

It has subsequently been determined that metallic blocks may also be used for the end blocks and the top block of a mold structure. However, the warpage preventing means disclosed in U.S. Pat. No. 3,544,058 have not been found equally suited for use on the top and end blocks.

BRIEF DESCRIPTION OF THE INVENTION Applicant has solved the above problems and others by providing a metallic block usable in a slab mold structure. The metallic block has a plurality of spaced slits starting at the rearward surface and extending toward the casting cavity. These slits are preferably in the neighborhood of three-fourths of the width of the block.

Lugs are attached to the upper and lower rearward surface of the block. Tie rods are engaged with the lugs and are fastened to maintain the longitudinal dimension of the rearward surface of the block. Adjustment means are provided on the tie rods to either draw the upper and lower surfaces closer together or permit them to expand longitudinally relative to each other.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional side elevational view taken through the casting cavity of a slab mold structure;

FIG. 2 is an enlarged side elevational view of the end block illustrated in FIG. 1; and

FIG. 3 is a sectional view taken at line 33 of FIG. 2.

DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a known adjustable slab mold 10 having opposed side blocks 12 (only one shown). This mold is similar to the one illustrated in U.S. Pat. No. 3,544,058, issued on Dec. 1, 1970. Hydraulic or other suitable devices (not shown) are provided for moving the side blocks toward and away from each other in a known manner. A plurality of inner blocks are interengaged between the side blocks 12 and include a top block 14, a bottom block 16 supported on a beam 18 and

end blocks

20 and 22 which together define a casting cavity 24. The height of the casting cavity 24 may be varied by raising or lowering the top block 14 by any number of known means, e.g., screws 26. The length of casting cavity 24 is also adjustable by means of suitable power devices 28, such as hydraulic cylinders, which may urge one end block 20 toward or away from the other end block 22.

In use molten metal is introduced under pressure from a pouring tube 30 upwardly through an ingate 32 and into casting cavity 24. A suitable riser construction 34 communicates with the casting cavity 24 to feed shrinkage which would otherwise develop in the casting during cooling.

The invention resides in an improved inner block and is illustrated in reference to end block 20. It should be appreciated that top block 14, bottom block 16 and end block 22 may also be modified in a like manner.

As illustrated in FIGS. 2 and 3, end block 20 is an elongated unitary member composed of a metal such as cast iron or carbon steel. A plurality of slots 36 extend transversely through block 20 from the rear surface 38 of the block forward toward the cavity defining surface a 40 which is substantially flat and continuous. The slots 36 are spaced at intervals along substantially the entire height of block 20 and extend forwardly for more than half but less than the entire width of the block. Preferably, the slots are in the neighborhood of threefourths of the width of block 20. Round holes 42 are located at the inward end of each slot 36 to relieve stress concentrations and to prevent tearing of block 20 during thermal expansion and contraction.

Shims, the same thickness as the opening of the slots, are located in each slot 36. The shims are preferably the width of block 20 and extend from rear surface 38 to holes 42.

Means 44 are provided to resist thermal distortion of block 20 during casting. These means 44 may take the form of

lugs

46 and 48 secured at the upper and lower extremities of the rear surface 38 of block 20. A bolt 50 engaged with a washer 52 projects through an opening in upper lug 46 and is in threaded engagement with a center portion of a trunnion 54. The trunnion 54 has opposed cylindrical arms 58 projecting through openings in

opposed tie rods

60 and 62. The

tie rods

60 and 62 extend along the length of block 20 and terminate proximate lug 48 which comprises

opposed shear blocks

64 and 66 outwardly spaced from a center shear block 68. A cylindrical pin 70 projects through openings in shear block 64, tie rod 60, shear block 68, tie rod 62 and shear block 66. A small pin 72 may project through shear block 68 and pin 70 to prevent movement of pin 70 relative to components 60 through 68.

A metal plate 74 is located

intermediate tie rods

60 and 62 and is partially located within a groove 76 which extends along the length of block 20. Pins or bolts 78 intermediate spaced grooves 36 project through openings in block 20 and elongated slots in plate 74 to retain plate 74 to block 20. Suitable power devices 28, previously described, are secured to plate 74 and are mounted to permit movement of block 20 relative to the remaining inner blocks of mold 10.

In operation, end block 20 is located in casting cavity 24. Bolt 50 is tightened until the appropriate amount of force is applied to the rearward surface 38 of block 20. The remaining mold structure is prepared for casting and molten metal is then forced upwardly through ingate 30 into casting cavity 24. As molten metal contacts block 20, cavity defining surface 40 tends to elongate more rapidly than the portions of block closer to rearward surface 38

proximate tie rods

60 and 62. The portions of block 20 near cavity defining surface 40 are under compressive stress while the portions closer to rear surface 38 are under a tensile stress. Since the material near surface 40 is at a higher temperature than the portions of block 20 closer toward rear surface 38, surface 40 has less strength and is therefore subject to compressive yielding. If such compressive yielding is allowed to exist, when block 20 cools, surface 40 will be shorter than the portion of block 20 closer to rear surface 38 causing block 20 to become concave.

Compressive yielding is resisted in block 20 by the slots 36, the shims and the

tie rods

60 and 62. The slots 36 reduce the area in which compressive yielding may occur. The

tie rods

60 and 62 provide the necessary force to keep block 20 substantially straight along cavity defining surface 40 by resisting the stresses which tend to open slots 36. The force exerted by the

tie rods

60, 62, to a certain degree further acts in such a way that a fulcrum is created by each shim at the end of each slot 36 proximate the corresponding hole 42. The force acting about these fulcrums has a tendency to counteract the shrinkage that normally would occur at surface 40 when block 20 cools.

I claim:

1. In a mold assembly having a plurality of inner blocks interengaged between a pair of side blocks to define a casting cavity, one of the inner blocks being a slotted metallic block having a plurality of spaced transverse slots extending from a rearward surface of the slotted block inwardly toward a forward cavity defining surface of the slotted block intermediate first and second end surfaces for more than one-half the width of the slotted block, a tie rod assembly comprising a first lug connected to a rearward portion of the slotted block proximate the first end surface, a second lug connected to the rearward portion of the slotted block proximate the second end surface, and a tension means interconnected to the first and second lug for applying force to said rearward surface to resist the stresses which tend to open the slots 'and warp said block during thermal expansion and contraction.

2. A mold assembly according to claim 1 wherein the first lug is located intermediate the first end surface and a slot adjacent the first end surface and the second lug is located intermediate the second end surface and a slot adjacent the second end surface.

3. A mold assembly according to claim 1 wherein the tension means comprises spaced tie rods having first and second ends, a trunnion is connected to the first ends of the spaced tie rods, and adjustable fastening means are engaged with the first lug and the trunnion to move the trunnion toward the first lug to place tensional stresses on the tie rods.

4. A mold assembly according to claim 3 wherein pin means interconnect the second lug and the second ends of the tie rods.

5. A mold assembly according to claim 4 wherein the first lug is located intermediate the first end surface and a slot adjacent the first end surface and the second lug is located intermediate the second end surface and a slot adjacent the second end surface.

6. A mold assembly according-to claim 1 wherein the rearward portion of the slotted block has a groove located therein and extending substantially along the length of the slotted block, a plate is located in the groove, and pin means secure the plate to the slotted block, the pin means being located intermediate adjacent slots.

7. A mold assembly according to claim 1 wherein holes are located at the inner end of each slot, and a shim is located in each slot, the shim extends from the rearward surface of the slotted block to the hole and has a thickness generally equal to the thickness of the opening of the slot.

Claims

1. In a mold assembly having a plurality of inner blocks interengaged between a pair of side blocks to define a casting cavity, one of the inner blocks being a slotted metallic block having a plurality of spaced transverse slots extending from a rearward surface of the slotted block inwardly toward a forward cavity defining surface of the slotted block intermediate first and second end surfaces for more than one-half the width of the slotted block, a tie rod assembly comprising a first lug connected to a rearward portion of the slotted block proximate the first end surface, a second lug connected to the rearward portion of the slotted block proximate the second end surface, and a tension means interconnected to the first and second lug for applying force to said rearward surface to resist the stresses which tend to open the slots and warp said block during thermal expansion and contraction.

6. A mold assembly according to claim 1 wherein the rearward portion of the slotted block has a groove located therein and extending substantially along the length of the slotted block, a plate is located in the groove, and pin means secure the plate to the slotted block, the pin means being located intermediate adjacent slots.