US3037873A - Method and composition for coating molds - Google Patents
Method and composition for coating molds Download PDFInfo
- Publication number
- US3037873A US3037873A US19513A US1951360A US3037873A US 3037873 A US3037873 A US 3037873A US 19513 A US19513 A US 19513A US 1951360 A US1951360 A US 1951360A US 3037873 A US3037873 A US 3037873A
- Authority
- US
- United States
- Prior art keywords
- mold
- composition
- mesh
- coating
- moisture
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000000203 mixture Substances 0.000 title claims description 47
- 238000000576 coating method Methods 0.000 title claims description 20
- 239000011248 coating agent Substances 0.000 title claims description 18
- 238000000034 method Methods 0.000 title description 7
- 239000004615 ingredient Substances 0.000 claims description 11
- 229910052751 metal Inorganic materials 0.000 description 14
- 239000002184 metal Substances 0.000 description 14
- 235000010469 Glycine max Nutrition 0.000 description 13
- 235000013312 flour Nutrition 0.000 description 12
- 239000000454 talc Substances 0.000 description 12
- 229910052623 talc Inorganic materials 0.000 description 12
- 229920002472 Starch Polymers 0.000 description 11
- RSWGJHLUYNHPMX-UHFFFAOYSA-N Abietic-Saeure Natural products C12CCC(C(C)C)=CC2=CCC2C1(C)CCCC2(C)C(O)=O RSWGJHLUYNHPMX-UHFFFAOYSA-N 0.000 description 10
- KHPCPRHQVVSZAH-HUOMCSJISA-N Rosin Natural products O(C/C=C/c1ccccc1)[C@H]1[C@H](O)[C@@H](O)[C@@H](O)[C@@H](CO)O1 KHPCPRHQVVSZAH-HUOMCSJISA-N 0.000 description 10
- 235000019698 starch Nutrition 0.000 description 10
- KHPCPRHQVVSZAH-UHFFFAOYSA-N trans-cinnamyl beta-D-glucopyranoside Natural products OC1C(O)C(O)C(CO)OC1OCC=CC1=CC=CC=C1 KHPCPRHQVVSZAH-UHFFFAOYSA-N 0.000 description 10
- 239000000463 material Substances 0.000 description 9
- 239000008107 starch Substances 0.000 description 9
- 239000008199 coating composition Substances 0.000 description 7
- 229910000831 Steel Inorganic materials 0.000 description 6
- 239000010959 steel Substances 0.000 description 6
- 229920001592 potato starch Polymers 0.000 description 5
- 239000002893 slag Substances 0.000 description 5
- 239000002023 wood Substances 0.000 description 5
- 238000005266 casting Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000007664 blowing Methods 0.000 description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- 229920002261 Corn starch Polymers 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 239000008120 corn starch Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000002274 desiccant Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 244000068988 Glycine max Species 0.000 description 1
- 240000003183 Manihot esculenta Species 0.000 description 1
- 235000016735 Manihot esculenta subsp esculenta Nutrition 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000007767 bonding agent Substances 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 235000019645 odor Nutrition 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C3/00—Selection of compositions for coating the surfaces of moulds, cores, or patterns
Definitions
- the present invention is directed to a method of and compositions for coating the inner surfaces of molds which are to receive molten metals at a high temperature.
- the invention is particularly applicable to the coating of metal molds employed for casting steel and other ferrous alloys.
- Very substantial improvements in mold coating are achieved through the use of a dry process in which the constituents, in finely divided powder form are applied by means of a spray gun in a stream of air.
- the coating composition may be applied while the mold is at an elevated temperature so that it is not necessary to cool the mold further after stripping and prior to a second pouring.
- compositions which are particularly suitable for thi use.
- the compositions there described consisted of a substantial proportion of a starchy material, a resin, and a drying agent of a calcareous nature. While these compositions were very effective under ordinary conditions of use, they some times exhibited a tendency to create significant amounts of slag in the mold. It appears that this slag formation may have been due to the presence of the calcium in the compositions.
- the present invention represents the distinct improvement upon the compositions and methods described in my aforementioned previous patent.
- I can coat molds over a wider range of temperatures both higher and lower than previously.
- the principal reason for this is the fact that I include an improved low temperature binder in the new composition.
- the compositions of the present invention are stable at temperatures even beyond those which could be ematent Q ployed with the compositions of the previous invention, without the attendant difliculties of significant slag formation because the newly developed compositions are calcium free.
- An object of the present invention is to provide an improvide composition for coating the inner surfaces of molds to prevent adherence of splashed molten metal.
- Another object of the present invention is to provide an improved method for coating the interior surfaces of a mold over a wide temperature range.
- Still another object of the invention is to provide an improved composition for coating metal molds which does not contribute slag forming ingredients to the molten metal contained in the mold.
- a further object of the invention is to provide an improved method for application of mold coating compositions to hot molds.
- I employ the combination of a starchy material, a resinous bonding agent, a bituminous composition, and talc in the form of a finely divided mixture.
- compositions of the invention include starchy or farinaceous material containing less than about 15% moisture.
- Various starches can be employed, but I prefer to employ potato starch, either alone, or in combination with other vegetable starches such as soy bean starch, tapioca starch, or corn starch.
- the principal function of the starch is to provide a film forming agent for the composition.
- soy flour in the composition.
- the soy flour should contain no more than 15% moisture to function properly.
- a resin or gum particularly a light colored wood or gum rosin having a melting point of more than about 200 F.
- bituminous material of which powdered pitch is the best example.
- powdered pitch A commercially available powdered pitch material having a melting point of about 250 C. (482 F.) is particularly preferred.
- the talc is employed both as a refractory additive to improve the high temperature behavior of the coating, and also as -a drying agent to permit the storage of the coating composition without caking or lumping.
- the ingredients are blended into the sprayable composition by thoroughly blending the dry ingredients, and then passing the mixture through a 150 mesh screen.
- the material may then be applied to the interior surfaces of an ingot mold or the like by blowing the composition in powdered form under a positive air pressure into the mold.
- the binder ingredients melt or soften to adhere to the wall and bind the remaining of the solids to the surface.
- Example I -A coating composition containing the following ingredients was prepared:
- Example 111 A metal mold was coated with the following composition:
- Percent Potato starch (11% moisture), 200 to 400 mesh 50 Soy flour (12% moisture), 200 to 250 mesh 20 Wood rosin, 150 to 400 mesh Powdered pitch, 150 to 400 mesh Talc 5 A steel ingot solidified in the mold coated with the foregoing composition was easily stripped from the mold without significant surface defects, and without impairing the surface of the mold. 7
- Example IV Another mold for casting steel ingots was coated with the following composition:
- Percent Potato starch (11% moisture), 200 to 400 mesh 30 Soy flour (m /2% moisture), 200 to 350 mesh 30 Wood rosin, 150 to 350 mesh 20 Powdered pitch, 150 to 250 mesh 15 Talc 5
- the finely divided mixture was sprayed by means of a conventional spray gun in a current of air onto the inner surfaces of a metal mold used for casting steel.
- the ingot which resulted was stripped from the mold Without difliculty and the mold surfaces were clean after the stripping. No evidence of additional slag formation was 1. determined due to the presence of the coating composition.
- a dry, finely divided, air transportable composition for coating the inner surfaces of a mold comprising a finely divided mixture containing the following ingredients:
- a dry, finely divided, air transportable composition for coating the inner surfaces of a mold comprising a finely divided mixture containing the following ingredients:
- a dry, finely divided, air transportable composition for coating the inner surfaces of a mold comprising a finely divided mixture containing the following ingredients:
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Mold Materials And Core Materials (AREA)
Description
States finite The present invention is directed to a method of and compositions for coating the inner surfaces of molds which are to receive molten metals at a high temperature. The invention is particularly applicable to the coating of metal molds employed for casting steel and other ferrous alloys.
When steel ingots are cast within a metal mold, molten steel is frequently splashed onto the sides of the mold during the pouring of the metal, and the splashed metal solidifies before the remainder of the ingot solidifies. This solidified metal on the sides of the mold may produce surface defects on the surface of the ingot which may manifest themselves as marks, slivers, or seams. The presence of these solidified deposits also gives rise to strains which tear the outer surface of the ingot during its solidification. In addition, the solidified splashed metal remains on the interior surfaces of the mold after the ingot has been stripped from the mold, thereby necessitating careful and time consuming cleaning and reconditioning of the mold prior to its reuse in another casting.
In the past, various means have been employed to provide an interface between the molten metal and the mold Walls in order to minimize the adherence of molten metal splashes to the interior mold surfaces. Frequently, these mold coating compositions had taken the form of liquid coatings such as pitch or tar. However, this type of mold coating composition in necessarily limited in its applicability because at even relatively modest temperatures, the carbonaceous materials will tend to burn or become charred, resulting in the evolution of smoke and odors which are very objectionable. Furthermore, with the use of such materials, it was necessary to cool the mold substantially prior to pouring so that the coating would adhere to the inner surfaces of the mold.
Very substantial improvements in mold coating are achieved through the use of a dry process in which the constituents, in finely divided powder form are applied by means of a spray gun in a stream of air. The coating composition may be applied while the mold is at an elevated temperature so that it is not necessary to cool the mold further after stripping and prior to a second pouring.
' In my previous Patent No. 2,578,976, issued December 18, 1951, I have described compositions which are particularly suitable for thi use. Basically, the compositions there described consisted of a substantial proportion of a starchy material, a resin, and a drying agent of a calcareous nature. While these compositions were very effective under ordinary conditions of use, they some times exhibited a tendency to create significant amounts of slag in the mold. It appears that this slag formation may have been due to the presence of the calcium in the compositions.
The present invention represents the distinct improvement upon the compositions and methods described in my aforementioned previous patent. With the compositions of the present invention, I can coat molds over a wider range of temperatures both higher and lower than previously. The principal reason for this is the fact that I include an improved low temperature binder in the new composition. More important, however, is the fact that the compositions of the present invention are stable at temperatures even beyond those which could be ematent Q ployed with the compositions of the previous invention, without the attendant difliculties of significant slag formation because the newly developed compositions are calcium free.
An object of the present invention is to provide an improvide composition for coating the inner surfaces of molds to prevent adherence of splashed molten metal.
Another object of the present invention is to provide an improved method for coating the interior surfaces of a mold over a wide temperature range.
Still another object of the invention is to provide an improved composition for coating metal molds which does not contribute slag forming ingredients to the molten metal contained in the mold.
A further object of the invention is to provide an improved method for application of mold coating compositions to hot molds.
In accordance with the present invention, I employ the combination of a starchy material, a resinous bonding agent, a bituminous composition, and talc in the form of a finely divided mixture.
The preferred compositions of the invention include starchy or farinaceous material containing less than about 15% moisture. Various starches can be employed, but I prefer to employ potato starch, either alone, or in combination with other vegetable starches such as soy bean starch, tapioca starch, or corn starch. The principal function of the starch is to provide a film forming agent for the composition.
In order to achieve the maximum amount of adherence at relatively low temperatures, I prefer to include soy flour in the composition. As in the case of the starchy materials, the soy flour should contain no more than 15% moisture to function properly.
Additional low temperature binding effects are achieved through the inclusion of a resin or gum, particularly a light colored wood or gum rosin having a melting point of more than about 200 F.
Improved bonding at moderately elevated temperatures is provided by adding the bituminous material, of which powdered pitch is the best example. A commercially available powdered pitch material having a melting point of about 250 C. (482 F.) is particularly preferred.
The talc is employed both as a refractory additive to improve the high temperature behavior of the coating, and also as -a drying agent to permit the storage of the coating composition without caking or lumping.
The relative percentages of the various degrees of the composition, together with the range of particle sizes employed for each, is given in the following table:
Ingredient Particle size Percent by weight Starch 200 to 400 mesh 30-60 Soy flour 200 to 250 mesh 1030 esin to 400 mesh 15-35 Bituminous 150 to 400 mesh 10-20 Talc l 200 to 400 mesh 5-10 For best results, it is important that the total moisture content of the composition not exceed 8% by weight.
The ingredients are blended into the sprayable composition by thoroughly blending the dry ingredients, and then passing the mixture through a 150 mesh screen. The material may then be applied to the interior surfaces of an ingot mold or the like by blowing the composition in powdered form under a positive air pressure into the mold. When the composition contacts the heated mold wall, the binder ingredients melt or soften to adhere to the wall and bind the remaining of the solids to the surface. With the types of compositions indicated above, I have successfully supplied coatings on mold surfaces 3 having temperatures as high as 950 F. although it is preferable, if possible, to work on a mold which has a temperature of about 700 to 750 F. because adherence is at its best in this temperature range.
The following specific examples illustrate the types of formulae coming. within the scope of the invention and the results achieved:
Example I -A coating composition containing the following ingredients was prepared:
' Percent Potato starch Il /2% moisture), 200 to 400 mesh--- 20 Corn starch (7 4% moisture), 200 to 400 mesh 20 Wood rosin, 150 to 300 mesh 30 Soy flour (12% moisture), 200 to 250 mesh 15 Powdered pitch, 150 to 400 mesh 10 Talc, 400 mesh 5 Example I! A slightly modified composition was prepared from the following ingredients:
7 Percent Potato starch (11% moisture), 200 to 400 mesh 35 Soy flour (12% moisture), 200 to 250 mesh 25 Wood rosin, 150 to 300 mesh 20 Powdered pitch, 150 to 400 mesh 15 Talc, 4G0 mesh- 5 The aforegoing composition was particularly effective in coating molds which had a lower surface temperature. As in the case of the material of Example I, the ingot was stripped from the mold cleanly, and the mold itself remained clean.
Example 111 A metal mold was coated with the following composition:
Percent Potato starch (11% moisture), 200 to 400 mesh 50 Soy flour (12% moisture), 200 to 250 mesh 20 Wood rosin, 150 to 400 mesh Powdered pitch, 150 to 400 mesh Talc 5 A steel ingot solidified in the mold coated with the foregoing composition was easily stripped from the mold without significant surface defects, and without impairing the surface of the mold. 7
Example IV Another mold for casting steel ingots was coated with the following composition:
Percent Potato starch (11% moisture), 200 to 400 mesh 30 Soy flour (m /2% moisture), 200 to 350 mesh 30 Wood rosin, 150 to 350 mesh 20 Powdered pitch, 150 to 250 mesh 15 Talc 5 The finely divided mixture was sprayed by means of a conventional spray gun in a current of air onto the inner surfaces of a metal mold used for casting steel. The ingot which resulted was stripped from the mold Without difliculty and the mold surfaces were clean after the stripping. No evidence of additional slag formation was 1. determined due to the presence of the coating composition.
It will be evident that various modifications can be made to the described embodiments without departing from the scope of the present invention.
I claim as my invention:
1. A dry, finely divided, air transportable composition for coating the inner surfaces of a mold comprising a finely divided mixture containing the following ingredients:
Percent by weight Starch 30 to 60 Soy flour 10 to 30 Rosin 15 to 35 Pitch 10 to 20 Talc 5 to 10 2. A dry, finely divided, air transportable composition for coating the inner surfaces of a mold comprising a finely divided mixture containing the following ingredients:
Percent by weight Starch 30 to 60 Soy flour a- 10 to 30 Rosin 15 to 35 Pitch 10 to 20 Talc 5 to 10 said composition containing no more than 8% by weight of moisture.
3. A dry, finely divided, air transportable composition for coating the inner surfaces of a mold comprising a finely divided mixture containing the following ingredients:
Percent by weight Starch (200 to 400 mesh) 30 to 60 Soy flour (200 to 250 mesh) 10 to 30 Rosin to 400 mesh) 15 to 35 Pitch (150 to 400 mesh) 10 to 20 Talc (200 to 400 mesh) 5 to 10 4. The method of coating the inner surfaces of a mold having a surface temperature of up to 950 F. which comprises blowing against said surface an air stream carrying a finely divided mixture having the following composition:
Percent by weight Starch 30 to 60 Soy flour 10 to 30 Rosin 15 to 35 Pitch 10 to 20 Talc Sto 10 until an appreciable coating of said mixture appeared on said surface.
5. The method of coating the inner surfaces of a mold having a surface temperature of up to 950 P. which comprises blowing against said surface an air stream carrying a finely divided mixture having the following composition:
, Percent by weight Starch 30 to 60 Soy flour 10 to 30 Rosin 15 to 35 Pitch 10 to 20 Talc 5 to 10 moisture not more than 8%, until an appreciable coating of said mixture appears on said surface.
References Cited in the file of this patent UNITED STATES PATENTS 2,476,933 Wallace July 19, 1949 2,578,976 Ingala Dec. 18, 1951 FOREIGN PATENTS 14,571 Great Britain of 1893
Claims (1)
1. A DRY, FINELY DIVIDED, AIR TRANSPORTABLE COMPOSITION FOR COATING THE INNER SURFACES OF A MOLD COMPRISES A FINELY DIVIDED MIXTURE CONTAINING THE FOLLOWING INGREDIENTS:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US19513A US3037873A (en) | 1960-04-04 | 1960-04-04 | Method and composition for coating molds |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US19513A US3037873A (en) | 1960-04-04 | 1960-04-04 | Method and composition for coating molds |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3037873A true US3037873A (en) | 1962-06-05 |
Family
ID=21793611
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US19513A Expired - Lifetime US3037873A (en) | 1960-04-04 | 1960-04-04 | Method and composition for coating molds |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US3037873A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3376914A (en) * | 1963-11-04 | 1968-04-09 | Foseco Int | Production of metal ingots, slabs and billets |
| US3519457A (en) * | 1965-12-30 | 1970-07-07 | Roderic H Hammerton | Treatment of ingot moulds |
| US3903025A (en) * | 1973-11-06 | 1975-09-02 | Gen Refractories Co | Method for cold molding pitch bonded refractory |
| US4017433A (en) * | 1973-11-06 | 1977-04-12 | General Refractories Company | Pitch water soluble resin and alkyd resin as binder composition for refractory particles |
| US5731272A (en) * | 1993-08-25 | 1998-03-24 | Kabushiki Kaisha Kobe Seiko Sho | Lubricant and method of manufacturing briquette using the same |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB189314571A (en) * | 1893-07-29 | 1894-07-28 | James Seymour Phillip Stutley | Improvements in certain Moulds used in the Casting of Metals. |
| US2476933A (en) * | 1946-04-04 | 1949-07-19 | Burgess P Wallace | Manufacture of facing compositions for metal casting molds |
| US2578976A (en) * | 1949-07-02 | 1951-12-18 | Ingala Frank | Method of coating ingot molds and composition therefor |
-
1960
- 1960-04-04 US US19513A patent/US3037873A/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB189314571A (en) * | 1893-07-29 | 1894-07-28 | James Seymour Phillip Stutley | Improvements in certain Moulds used in the Casting of Metals. |
| US2476933A (en) * | 1946-04-04 | 1949-07-19 | Burgess P Wallace | Manufacture of facing compositions for metal casting molds |
| US2578976A (en) * | 1949-07-02 | 1951-12-18 | Ingala Frank | Method of coating ingot molds and composition therefor |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3376914A (en) * | 1963-11-04 | 1968-04-09 | Foseco Int | Production of metal ingots, slabs and billets |
| US3519457A (en) * | 1965-12-30 | 1970-07-07 | Roderic H Hammerton | Treatment of ingot moulds |
| US3903025A (en) * | 1973-11-06 | 1975-09-02 | Gen Refractories Co | Method for cold molding pitch bonded refractory |
| US4017433A (en) * | 1973-11-06 | 1977-04-12 | General Refractories Company | Pitch water soluble resin and alkyd resin as binder composition for refractory particles |
| US5731272A (en) * | 1993-08-25 | 1998-03-24 | Kabushiki Kaisha Kobe Seiko Sho | Lubricant and method of manufacturing briquette using the same |
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