METHOD FOR STRIPPING INGOT MOLDS
United States Patent 3570584
A method and apparatus for stripping a big-end-up ingot mold in which a mold is used having a hole through the bottom thereof which is filled with a plug and having at least one recess in the top thereof which is covered with a hot top. A wedge member is inserted in the recess which acts to jam the teemed ingot in a raised position when the ingot is rammed upwardly out of the mold.
US Patent References:
/1206150.html
Slick - November 1916 - 1206150
Feeder for ingot molds
Howard et al. - January 1925 - 1523203
Feeder for ingot molds
Howard et al. - January 1925 - 1523204
Apparatus for stripping ingot molds
Anderson - October 1935 - 2017384
Apparatus for stripping ingots
Dornin - June 1937 - 2085212
/1206150.html
Slick - November 1916 - 1206150
Feeder for ingot molds
Howard et al. - January 1925 - 1523203
Feeder for ingot molds
Howard et al. - January 1925 - 1523204
Apparatus for stripping ingot molds
Anderson - October 1935 - 2017384
Apparatus for stripping ingots
Dornin - June 1937 - 2085212
Application Number:
04/769137
Publication Date:
03/16/1971
Filing Date:
10/21/1968
View Patent Images:
Export Citation:
Assignee:
Rio Algom Mines Limited (Toronto, Ontario, CA)
Primary Class:
Other Classes:
164/347, 249/197, 249/106, 164/406
International Classes:
B22D29/04; B22D29/00; B22D29/04
Field of Search:
164/131,213,227,226,269,344,347,401,404,405,406 299/106,197,198,201
Primary Examiner:
Overholser, Spencer J.
Assistant Examiner:
Roethel, John E.
Claims:
I claim
1. A method of stripping a big-end-up ingot from a mold which comprises providing at least one recess in the mold wall at the top thereof and open to the top of the mold, covering said recess with a hot top to prevent flow of molten metal thereinto, inserting a wedge member into said recess longer than the thickness of the recess in the mold wall so that said wedge member has an upper end leaning against said hot top, providing a hole through the bottom of the mold which is filled with a plug before teeming, inserting a ram into said bottom hole and ramming the teemed ingot and the hot top upwardly out of said mold to allow the upper end of said wedge member to fall against said ingot, withdrawing said ram to allow the ingot to be jammed and held in a raised position by said wedge member and removing said ingot from said mold.
2. A method of stripping an ingot as defined in claim 1 wherein two recesses are provided in the mold, one each in opposite sidewalls thereof.
3. A method of stripping an ingot as defined in claim 2 wherein two wedges are used, one being inserted in each recess.
4. A method of stripping an ingot as defined in claims 1, 2 or 3 wherein each recess provided in the mold wall is a substantially narrow slot just wide enough to allow free fall of the wedge against the ingot when the ingot is rammed upwardly out of the mold.
1. A method of stripping a big-end-up ingot from a mold which comprises providing at least one recess in the mold wall at the top thereof and open to the top of the mold, covering said recess with a hot top to prevent flow of molten metal thereinto, inserting a wedge member into said recess longer than the thickness of the recess in the mold wall so that said wedge member has an upper end leaning against said hot top, providing a hole through the bottom of the mold which is filled with a plug before teeming, inserting a ram into said bottom hole and ramming the teemed ingot and the hot top upwardly out of said mold to allow the upper end of said wedge member to fall against said ingot, withdrawing said ram to allow the ingot to be jammed and held in a raised position by said wedge member and removing said ingot from said mold.
2. A method of stripping an ingot as defined in claim 1 wherein two recesses are provided in the mold, one each in opposite sidewalls thereof.
3. A method of stripping an ingot as defined in claim 2 wherein two wedges are used, one being inserted in each recess.
4. A method of stripping an ingot as defined in claims 1, 2 or 3 wherein each recess provided in the mold wall is a substantially narrow slot just wide enough to allow free fall of the wedge against the ingot when the ingot is rammed upwardly out of the mold.
Description:
BACKGROUND OF THE INVENTION
The teeming of molten metal into big-end-up ingots is a very common practice in the casting art but there have always been problems associated with stripping the mold once the ingot has solidified. Certain procedures involve the use of superimposed hot tops projecting upwardly from the mold which are removed after solidification with the projecting portion of the ingot then being loosened in the mold and grasped with tongs to be pulled out. There are no real problems associated with the stripping of ingots utilizing superimposed hot tops but such hot tops are usually quite expensive to form and put in place and are destroyed in the stripping operations. Furthermore, a large amount of wastage results from an ingot cast while utilizing a superimposed hot top. Fully inserted hot tops result in decreased wastage but the ingots are difficult to hold and transportation of the ingot using the tongs some distance to the soaking pit or working operations presents problems, a major one being considerable danger to workmen involved in the operations. Transportation of the mold and contained ingot to the soaking pit or working operations can eliminate carrying of the ingot itself too great a distance but the ingot, even though loosened, is still difficult to remove from the mold at the site of the soaking pit and the mold must then, of course, be returned to the teeming operation.
U.S. Pat. No. 1,039,725 discloses the use of refractory inserts at the top of a mold which are removed after teeming to provide gripping cavities for an ingot lifting device. In U.S. Pat. Nos. 1,749,723 and 2,017,385 stripping procedures are disclosed using leverage techniques by which tongs act downwardly on the mold and upwardly on the ingot to raise the ingot out of the mold. U.S. Pat. Nos. 1,288,023, 1,963,307 and 2,017,384 disclose variations of procedures by which the ingot is pushed upwardly out of the mold through a hole in the bottom thereof. In the procedure of the first of these three patents a wedge may be inserted between the mold wall and the ingot after the ingot has been pushed upwardly out of the mold. In the method of U.S. Pat. No. 2,485,065 refractory inserts are cemented to the inner wall of the hot top before teeming. The hot top is removed as are the inserts after teeming with gripping holes thereby being provided in the top of the ingot.
It has now been discovered that a big-end-up ingot utilizing a fully inserted hot top can be rammed upwardly out of the mold into which it has been teemed and can be jammed and held in a raised position in the mold, prior to subsequent complete removal from the mold, by a simple and inexpensive procedure.
SUMMARY
In the method and apparatus of the invention a big-end-up ingot mold is provided with at least one recess in the mold wall at the top thereof which is open to the top of the mold. Two such recesses are advantageously provided in opposite walls of the mold. A hot top is placed on top of the mold extending down thereinto to cover the recesses and prevent flow of molten metal therein. A wedge member longer than the thickness of the recess in the mold wall is inserted in a recess with the upper end of the wedge leaning against the hot top. The mold is provided with a hole through the bottom thereof which is plugged with plug before teeming. After teeming the ingot and hot top are moved upwardly out of the mold by inserting a ram through the hole in the bottom of the ingot to force the plug inwardly out of the hole and push the ingot upwardly. This procedure allows the wedge member to fall against the side of the ingot and act to jam and hold the ingot in a raised position in the mold when the ram is withdrawn. The ingot is then easily grasped and withdrawn from the mold when required.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of a big-end-up ingot mold provided with recesses and a wedge member in accordance with an embodiment of the invention;
FIG. 2 is an elevational view in section of the mold of FIG. 1 showing a hot top and a wedge member in place with the ingot having been teemed;
FIG. 3 is a sectional view of the mold as shown in FIG. 2 but with the ingot having been rammed upwardly in the mold and being held in a raised position; and
FIG. 4 is an enlarged view of a recess in the top of a mold showing a wedge member in position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings and in particular to FIG. 1, a big-end-up ingot mold 10 modified in accordance with an embodiment of the invention is shown. The mold 10 has an ingot cavity 11, sidewalls 12, lower holding lugs 13 and upper lifting lugs 14. Two recesses 15 are located in and at the top of opposing sidewalls of the mold 10 with the recesses being open to the top of the mold. A wedge member 16 for location in one of the recesses 15 is shown in FIG. 1.
Referring to FIG. 2, a sectional view in elevation of the mold 10 of FIG. 1 is shown but with an ingot 17 teemed therein. The diverging sidewalls 12 of the mold 10 are clearly shown in FIG. 2 to produce the big-end-up ingot 17. A hot top 18 of refractory material is shown located in the top of the ingot cavity and extending downwardly thereinto, the hot top 18 having been put in position before teeming of the ingot 17. The recesses 15 are seen to be covered by the hot top 18 to prevent flow of molten metal thereinto. The wedge member 16 is located in one of the recesses 15 with the upper end of the wedge leaning against the hot top 18. An enlarged view of the wedge member 16 in position is shown in FIG. 4. The wedge member 16 must be longer than the thickness of the recess 15 in the mold wall and long enough to provide a wedging action between corner 19 of the recess and the solidified ingot 17 in the subsequent stripping operation. The particular wedge shown in FIGS. 1 and 2, and in an enlarged view in FIG. 4, is seen to be merely a piece of hexagonal bar stock. Other shapes of wedges can be used, such as specially made members with toothed upper ends to provide improved biting action on the ingot, but all that is necessary is that the wedge provides a jamming action to hold the ingot in a raised position in the mold as described hereinafter.
The mold 10 is seen to be provided with a hole 20 in bottom 21 of the mold which is filled with a plug member 22, which may be metal or refractory. A ram member 23 is provided for the operation of stripping the ingot 17 from the mold 10 with holding members 24 located over the holding lugs 13 to hold the mold down while the ram 22 (shown moving upwardly towards the hole 20 in FIG. 2) is ramming the ingot 17 upwardly out of the mold 10.
The stripping operation of the invention is illustrated by the sectional view in elevation shown in FIG. 3. The ram 23 has been moved upwardly through the hole 20 to push the ingot 17 upwardly out of the mold 10 while pushing the plug 22 upwardly into the mold and out of the way as shown. In the stripping operation shown in FIG. 3 the ingot 17, together with the hot top 18, was rammed into the position shown by broken lines 25 and the ram 23 is being withdrawn as shown. Movement of the ingot 17 together with the hot top 18 upwardly has allowed the wedge member 16 to come into contact with the ingot 17 and withdrawal of the ram 23 has caused the ingot 17 to settle back into the solid line position shown in FIG. 3. As a result the wedge member 16 has been jammed between the ingot 17 and the corner 19 of the recess 15 and the ingot 17 is firmly held in the position shown in FIG. 3.
It can be seen that with the ingot held in the raised position of FIG. 3 the mold 10 can be transported to any subsequent operation, such as to the soaking pit, with the ingot 17 being lifted clear with a grappling crane at such operation by grasping it at the hot top portion projecting above the mold. Although the stripping operation has been described with reference to the one holding wedge 16, a second wedge member 26 (shown in broken outline in FIG. 3) can be used, if desired, in the second recess 15. Where only one wedge is used (and only one is found to be actually necessary) only one recess need be provided in a mold, although two are more advantageous since a wedge can then be placed in either side of the mold without needing to bother with its orientation. It is found advantageous to provide the recesses 15 as substantially narrow slots, as shown in FIG. 1, which are just wide enough to allow free fall of a wedge against the ingot when the ingot is rammed upwardly out of the mold.
For the purpose of giving those skilled in the art a better understanding of the invention the following illustrative examples are given.
EXAMPLE I
A heat of SAE 8630-grade steel was teemed into 16 ingot molds, the total weight of steel poured being 69,400 pounds. The molds were a big-end-up type with a construction the same as that shown in the FIGS. of drawing herein. The molds had an inside cavity with a cross section of about 15 inches by 20 inches and the two recesses 15 (as shown in the drawing) were 41/2 inches long by 4 inches deep and had a width tapering outwardly to the mold cavity from 11/4 inches to 11/2 inches. Prior to teeming each ingot a single wedge member (16 on the drawing) cut into a 51/8 inch length from 1 inch hexagonal drill rod was placed in one of the recesses 15, after placing the hot top 18 in position. Each ingot was stripped from the mold by the stripping ram 23, as shown in FIGS. 2 and 3 of the drawing, and all 16 ingots were successfully held by the wedge members 16 in the raised position shown in FIG. 3 of the drawing and were then easily removed from the molds for transfer to soaking pits.
EXAMPLE II
A heat of 68,150 pounds of SAE 86 MAI-grade steel was teemed into 16 ingot molds as in Example I. The molds were the same and the stripping and holding techniques were the same as with Example I. Again, all 16 ingots were successfully held in the raised position before being easily removed and transferred to soaking pits.
EXAMPLE III
In this test 67,700 pounds of a 0.8 percent C hollow drill-grade steel was poured into 16 ingot molds, again using the same mold construction and the same stripping and holding procedures as with the previous two examples. There was difficulty in stripping two of the ingots because of sticking in the molds but the remaining 14 ingots were stripped from the molds and held in a raised position by the wedge members until they were easily removed from the molds and transferred to soaking pits.
EXAMPLE IV
This test involved pouring a heat of 64,700 pounds of SAE 5132 steel into 16 ingot molds. The same molds were used as with the previous examples and the same stripping and holding procedures were used. Only one of the ingots was not held in the raised position before removal from the molds and transfer to the soaking pits. As with the previous examples, because of the large portion of ingot being held above the top of the mold removal of an ingot and transfer to the soaking pit proceeded easily and with no danger.
It is to be observed that the procedure and apparatus of the invention are most advantageous for the casting and stripping of big-end-up ingots, and in particular with respect to ingot molds using fully inserted hot tops. The apparatus can be completely prepared before teeming of the ingot, thereby avoiding the necessity for workmen having to closely approach the top of the mold with the mold full of red hot metal. At the same time, the wedging procedure of the invention is seen to occur automatically and simply when the ingot has been rammed upwardly out of the mold and is firmly held in a raised position as long as necessary for further operations. Also no complicated and expensive apparatus is needed in order to provide the ingot wedging and holding operation of the invention.
The teeming of molten metal into big-end-up ingots is a very common practice in the casting art but there have always been problems associated with stripping the mold once the ingot has solidified. Certain procedures involve the use of superimposed hot tops projecting upwardly from the mold which are removed after solidification with the projecting portion of the ingot then being loosened in the mold and grasped with tongs to be pulled out. There are no real problems associated with the stripping of ingots utilizing superimposed hot tops but such hot tops are usually quite expensive to form and put in place and are destroyed in the stripping operations. Furthermore, a large amount of wastage results from an ingot cast while utilizing a superimposed hot top. Fully inserted hot tops result in decreased wastage but the ingots are difficult to hold and transportation of the ingot using the tongs some distance to the soaking pit or working operations presents problems, a major one being considerable danger to workmen involved in the operations. Transportation of the mold and contained ingot to the soaking pit or working operations can eliminate carrying of the ingot itself too great a distance but the ingot, even though loosened, is still difficult to remove from the mold at the site of the soaking pit and the mold must then, of course, be returned to the teeming operation.
U.S. Pat. No. 1,039,725 discloses the use of refractory inserts at the top of a mold which are removed after teeming to provide gripping cavities for an ingot lifting device. In U.S. Pat. Nos. 1,749,723 and 2,017,385 stripping procedures are disclosed using leverage techniques by which tongs act downwardly on the mold and upwardly on the ingot to raise the ingot out of the mold. U.S. Pat. Nos. 1,288,023, 1,963,307 and 2,017,384 disclose variations of procedures by which the ingot is pushed upwardly out of the mold through a hole in the bottom thereof. In the procedure of the first of these three patents a wedge may be inserted between the mold wall and the ingot after the ingot has been pushed upwardly out of the mold. In the method of U.S. Pat. No. 2,485,065 refractory inserts are cemented to the inner wall of the hot top before teeming. The hot top is removed as are the inserts after teeming with gripping holes thereby being provided in the top of the ingot.
It has now been discovered that a big-end-up ingot utilizing a fully inserted hot top can be rammed upwardly out of the mold into which it has been teemed and can be jammed and held in a raised position in the mold, prior to subsequent complete removal from the mold, by a simple and inexpensive procedure.
SUMMARY
In the method and apparatus of the invention a big-end-up ingot mold is provided with at least one recess in the mold wall at the top thereof which is open to the top of the mold. Two such recesses are advantageously provided in opposite walls of the mold. A hot top is placed on top of the mold extending down thereinto to cover the recesses and prevent flow of molten metal therein. A wedge member longer than the thickness of the recess in the mold wall is inserted in a recess with the upper end of the wedge leaning against the hot top. The mold is provided with a hole through the bottom thereof which is plugged with plug before teeming. After teeming the ingot and hot top are moved upwardly out of the mold by inserting a ram through the hole in the bottom of the ingot to force the plug inwardly out of the hole and push the ingot upwardly. This procedure allows the wedge member to fall against the side of the ingot and act to jam and hold the ingot in a raised position in the mold when the ram is withdrawn. The ingot is then easily grasped and withdrawn from the mold when required.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of a big-end-up ingot mold provided with recesses and a wedge member in accordance with an embodiment of the invention;
FIG. 2 is an elevational view in section of the mold of FIG. 1 showing a hot top and a wedge member in place with the ingot having been teemed;
FIG. 3 is a sectional view of the mold as shown in FIG. 2 but with the ingot having been rammed upwardly in the mold and being held in a raised position; and
FIG. 4 is an enlarged view of a recess in the top of a mold showing a wedge member in position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings and in particular to FIG. 1, a big-end-up ingot mold 10 modified in accordance with an embodiment of the invention is shown. The mold 10 has an ingot cavity 11, sidewalls 12, lower holding lugs 13 and upper lifting lugs 14. Two recesses 15 are located in and at the top of opposing sidewalls of the mold 10 with the recesses being open to the top of the mold. A wedge member 16 for location in one of the recesses 15 is shown in FIG. 1.
Referring to FIG. 2, a sectional view in elevation of the mold 10 of FIG. 1 is shown but with an ingot 17 teemed therein. The diverging sidewalls 12 of the mold 10 are clearly shown in FIG. 2 to produce the big-end-up ingot 17. A hot top 18 of refractory material is shown located in the top of the ingot cavity and extending downwardly thereinto, the hot top 18 having been put in position before teeming of the ingot 17. The recesses 15 are seen to be covered by the hot top 18 to prevent flow of molten metal thereinto. The wedge member 16 is located in one of the recesses 15 with the upper end of the wedge leaning against the hot top 18. An enlarged view of the wedge member 16 in position is shown in FIG. 4. The wedge member 16 must be longer than the thickness of the recess 15 in the mold wall and long enough to provide a wedging action between corner 19 of the recess and the solidified ingot 17 in the subsequent stripping operation. The particular wedge shown in FIGS. 1 and 2, and in an enlarged view in FIG. 4, is seen to be merely a piece of hexagonal bar stock. Other shapes of wedges can be used, such as specially made members with toothed upper ends to provide improved biting action on the ingot, but all that is necessary is that the wedge provides a jamming action to hold the ingot in a raised position in the mold as described hereinafter.
The mold 10 is seen to be provided with a hole 20 in bottom 21 of the mold which is filled with a plug member 22, which may be metal or refractory. A ram member 23 is provided for the operation of stripping the ingot 17 from the mold 10 with holding members 24 located over the holding lugs 13 to hold the mold down while the ram 22 (shown moving upwardly towards the hole 20 in FIG. 2) is ramming the ingot 17 upwardly out of the mold 10.
The stripping operation of the invention is illustrated by the sectional view in elevation shown in FIG. 3. The ram 23 has been moved upwardly through the hole 20 to push the ingot 17 upwardly out of the mold 10 while pushing the plug 22 upwardly into the mold and out of the way as shown. In the stripping operation shown in FIG. 3 the ingot 17, together with the hot top 18, was rammed into the position shown by broken lines 25 and the ram 23 is being withdrawn as shown. Movement of the ingot 17 together with the hot top 18 upwardly has allowed the wedge member 16 to come into contact with the ingot 17 and withdrawal of the ram 23 has caused the ingot 17 to settle back into the solid line position shown in FIG. 3. As a result the wedge member 16 has been jammed between the ingot 17 and the corner 19 of the recess 15 and the ingot 17 is firmly held in the position shown in FIG. 3.
It can be seen that with the ingot held in the raised position of FIG. 3 the mold 10 can be transported to any subsequent operation, such as to the soaking pit, with the ingot 17 being lifted clear with a grappling crane at such operation by grasping it at the hot top portion projecting above the mold. Although the stripping operation has been described with reference to the one holding wedge 16, a second wedge member 26 (shown in broken outline in FIG. 3) can be used, if desired, in the second recess 15. Where only one wedge is used (and only one is found to be actually necessary) only one recess need be provided in a mold, although two are more advantageous since a wedge can then be placed in either side of the mold without needing to bother with its orientation. It is found advantageous to provide the recesses 15 as substantially narrow slots, as shown in FIG. 1, which are just wide enough to allow free fall of a wedge against the ingot when the ingot is rammed upwardly out of the mold.
For the purpose of giving those skilled in the art a better understanding of the invention the following illustrative examples are given.
EXAMPLE I
A heat of SAE 8630-grade steel was teemed into 16 ingot molds, the total weight of steel poured being 69,400 pounds. The molds were a big-end-up type with a construction the same as that shown in the FIGS. of drawing herein. The molds had an inside cavity with a cross section of about 15 inches by 20 inches and the two recesses 15 (as shown in the drawing) were 41/2 inches long by 4 inches deep and had a width tapering outwardly to the mold cavity from 11/4 inches to 11/2 inches. Prior to teeming each ingot a single wedge member (16 on the drawing) cut into a 51/8 inch length from 1 inch hexagonal drill rod was placed in one of the recesses 15, after placing the hot top 18 in position. Each ingot was stripped from the mold by the stripping ram 23, as shown in FIGS. 2 and 3 of the drawing, and all 16 ingots were successfully held by the wedge members 16 in the raised position shown in FIG. 3 of the drawing and were then easily removed from the molds for transfer to soaking pits.
EXAMPLE II
A heat of 68,150 pounds of SAE 86 MAI-grade steel was teemed into 16 ingot molds as in Example I. The molds were the same and the stripping and holding techniques were the same as with Example I. Again, all 16 ingots were successfully held in the raised position before being easily removed and transferred to soaking pits.
EXAMPLE III
In this test 67,700 pounds of a 0.8 percent C hollow drill-grade steel was poured into 16 ingot molds, again using the same mold construction and the same stripping and holding procedures as with the previous two examples. There was difficulty in stripping two of the ingots because of sticking in the molds but the remaining 14 ingots were stripped from the molds and held in a raised position by the wedge members until they were easily removed from the molds and transferred to soaking pits.
EXAMPLE IV
This test involved pouring a heat of 64,700 pounds of SAE 5132 steel into 16 ingot molds. The same molds were used as with the previous examples and the same stripping and holding procedures were used. Only one of the ingots was not held in the raised position before removal from the molds and transfer to the soaking pits. As with the previous examples, because of the large portion of ingot being held above the top of the mold removal of an ingot and transfer to the soaking pit proceeded easily and with no danger.
It is to be observed that the procedure and apparatus of the invention are most advantageous for the casting and stripping of big-end-up ingots, and in particular with respect to ingot molds using fully inserted hot tops. The apparatus can be completely prepared before teeming of the ingot, thereby avoiding the necessity for workmen having to closely approach the top of the mold with the mold full of red hot metal. At the same time, the wedging procedure of the invention is seen to occur automatically and simply when the ingot has been rammed upwardly out of the mold and is firmly held in a raised position as long as necessary for further operations. Also no complicated and expensive apparatus is needed in order to provide the ingot wedging and holding operation of the invention.