US1902059A - Production of alloy surface castings - Google Patents
Production of alloy surface castings Download PDFInfo
- Publication number
- US1902059A US1902059A US526551A US52655131A US1902059A US 1902059 A US1902059 A US 1902059A US 526551 A US526551 A US 526551A US 52655131 A US52655131 A US 52655131A US 1902059 A US1902059 A US 1902059A
- Authority
- US
- United States
- Prior art keywords
- carbon
- alloy
- chromium
- powder
- ferrochromium
- 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
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D19/00—Casting in, on, or around objects which form part of the product
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12771—Transition metal-base component
- Y10T428/12861—Group VIII or IB metal-base component
- Y10T428/12951—Fe-base component
- Y10T428/12958—Next to Fe-base component
- Y10T428/12965—Both containing 0.01-1.7% carbon [i.e., steel]
Definitions
- the invention relates to the production of able high-chromium content.
- tion composed of steel or iron and alloy coatings which are high in chromium and are resistant to abrasion and corrosion. These alloy coatings may contain 12% or more of chromium but they commonly contain about 20% to of chromium.
- the castings are made by pouring the steel or iron into a mold which is covered with ferrochromium powder on the part or parts which correspond to the part or parts of the casting to be coated.
- alloy coated castings have been made by casting iron or steel into moldswhich were covered with a composition composed of powdered ferrochromium and a binder.
- Ferrochromium which contains about 70% chromium, 20% to 25% iron, 0.5% to 2% silicon, I carbon is easily reduced to powder ofthe desired sizes for this purpose. It alloys easily with the base metal and it has a suit- Consequently this high carbon ferrochromium alloy has universally been used for the purposes indicated.
- the alloy coatings made with this powder were defective, especially at or near the tops of surfaces which were disposed in a vertical position when the base metal was poured.
- Portions of the surfaces would be irregular or indented, presumably as a result of shrinkage during cooling and these portions, would be found to be uncoated with the high-chromium alloy. It then became necessary to fill in the uncoated portions by welding, using a filler rod which would deposit a composition similar to that of the coating.
- the main object of the invention is to provide means for preventing the described discontinuity in high-chromium alloy coatings.
- the practicable pouring temperatures commonly range from about 2650 t0 3000 F. It is necessary to use a powder which is sized so that the speed of combination of the core metal with the powder at the pouring temperatures and the proportions of base metal and powder which combine will be sufficient to produce an alloy coating with the desired chromium content and with such a perfect joining together that the layer of alloy cannot easily be chipped off, sealed off or separated from the base metal on bending or breaking.
- the powder is sized to exclude the coarsest and the finest particles. The largest particles are preferably of about the size which will just pass through a number 20 sieve and the smallest are those of about the size which will just be retained on sieve numbers 50 to 80.
- alloy steels and irons may be used for the base metal, that-the vertically disposed portions as well as the entire surface of the mold may be coated with the low carbon ferrochromium, that variations in the thickness of the coatings of powder and binder and in the grading of the size of the particles may be made to vary the thickness and character of the alloy coatings, and that the content of chromium and iron may be varied within wide limits without departing from the invention.
- the ferrochromium may range from about 60% to 97% chromium, the remainder except about 0.5% to 2.0% silicon and about 1.0% to 2.72% carbon being iron.
- I claim 1 The method of producing a casting having base metal composed of ferrous alloy and a coating composed of a chromium-containing alloy formed by the union of the cast metal and a lining of ferrochromium powder disposed on the casting mold, which comprises lining the mold with ferrochromium powder containing about 1.0% to about 1.25%
- a coatin'g for molds adapted to form a chromium-containing alloy surface on a ferrous alloy base metal cast in the mold which comprises a ferrochromium powder of such a size that the smallest particles will be retained on about number 40 to number 80 sieves and the largest particles will pass through number 16 to number 20. sieves, said powder containing carbon, but not more than about 2.72% carbon, about 0.5 to 2.0% silicon, about 60% to 97% chromium, and the remainder iron.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Mold Materials And Core Materials (AREA)
Description
Patented Mar. 21, 1933 UNITED STATES PATENT oar-"E JAMES H. GRITCHETT, OF DOUGLASTON, NEW YORK, ASSIGNOR TO ELECTRO METAL- LURGIGAL COMPANY, A CORPORATION OF WEST VIRGINIA PRODUCTION OF ALLOY SURFACE CASTINGS No Drawing.
The invention relates to the production of able high-chromium content.'
tion composed of steel or iron and alloy coatings which are high in chromium and are resistant to abrasion and corrosion. These alloy coatings may contain 12% or more of chromium but they commonly contain about 20% to of chromium. The castings are made by pouring the steel or iron into a mold which is covered with ferrochromium powder on the part or parts which correspond to the part or parts of the casting to be coated.
Heretofore alloy coated castings have been made by casting iron or steel into moldswhich were covered with a composition composed of powdered ferrochromium and a binder. Ferrochromium which contains about 70% chromium, 20% to 25% iron, 0.5% to 2% silicon, I carbon is easily reduced to powder ofthe desired sizes for this purpose. It alloys easily with the base metal and it has a suit- Consequently this high carbon ferrochromium alloy has universally been used for the purposes indicated. Frequently the alloy coatings made with this powder were defective, especially at or near the tops of surfaces which were disposed in a vertical position when the base metal was poured. Portions of the surfaces would be irregular or indented, presumably as a result of shrinkage during cooling and these portions, would be found to be uncoated with the high-chromium alloy. It then became necessary to fill in the uncoated portions by welding, using a filler rod which would deposit a composition similar to that of the coating.
The main object of the invention is to provide means for preventing the described discontinuity in high-chromium alloy coatings.
Experience 'has shown that the use of high-carbon ferrochromium for the coating of the mold requires that the temperatures and heat capacity of the casting as a whole be regulated within narrow limits. Whilev these conditions could be influenced to some extent by adjusting the pouring temperatures of the cast metal by the use of chills, the described defects could and about,,4% to 6%" Application filed MarchBO, 1931. Serial No. 526,551.
not always be overcome because it was not always possible to regulate the pouring temperatures or chilling in foundry practice within a sufficiently narrow range to give a heat balance which would produce perfect coatings. Even in castings where it was possible to regulate the heat balance by these means, it was costly to determine the exact pouring temperatures and the exact location for the chills. lVitha change in the size or shape of the casting the determination of new pouring temperatures or new chilling conditions was necessary.
The following example is illustrative of my invention. F errochromium containing about 67% to 70% chromium, 0.5% to 2.0% silicon and 1.0% to 1.25% carbon, and the balance chiefly iron waspowdered. Particles which passed through a number 20 sieve and were retained on a number 48 sieve were dampened with a sodium silicate solution and a layer of the composition about onesixteenth to one-eighth of an inch thick was placed on a mold which has a normally vertically disposed wall. The mold was dried and carbon steel containing about 0.5% carbon was poured into the mold. The cooled casting was found to have a continuous coating of high chromium alloy which could not be chipped from the base metal and no bare spots due to shrinkage were present.
It has been found that the defect can be overcome by using ferrochromium powder which contains about 1.0% to 2.72% carbon. Steel or iron can be used for the base metal, the invention being more advantageously applied in connection with base metals which contain relatively less carbon than the ferrochromium powder. The best results are generally obtained when the carbon content of the powder, the amount which the base metal dilutes the coating, and the carbon content of the base metal are regulated so that the carbon content of the surface alloy will be considerably below 2.7 say about 1.0% carbon. The greatest variations in pouring temperatures can be used when the carbon content of the coating alloy tends to be reduced continuously as the base metal continues to alloy with the ferrochromium powder, but the breaks in the coating can be avoided with wide variations in pouring temperatures even when the higher carbon base metals are used and the carbon-in the coating is built up approximately to 2.7% carbon.
- The exact reasons for the improvements which result from the use of the described low carbon ferrochromium are unknown to me. It is my present belief that the low carbon ferrochromium rapidly forms a coating alloy which solidifies more rapidly than the base metal when the temperature begins to drop and that a strong non-rupturing surface coating is formed before the base metal has had time to cool sufficiently to shrink. The formation of this non-rupturing surface alloy attemperatures above 'the shrinkage temperature of the base metal avoids the necessity for close regulation of the pouring temperatures and of other conditions which affect the heat balance.
The practicable pouring temperatures commonly range from about 2650 t0 3000 F. It is necessary to use a powder which is sized so that the speed of combination of the core metal with the powder at the pouring temperatures and the proportions of base metal and powder which combine will be sufficient to produce an alloy coating with the desired chromium content and with such a perfect joining together that the layer of alloy cannot easily be chipped off, sealed off or separated from the base metal on bending or breaking. The powder is sized to exclude the coarsest and the finest particles. The largest particles are preferably of about the size which will just pass through a number 20 sieve and the smallest are those of about the size which will just be retained on sieve numbers 50 to 80. Various selected sizes within these limits may be used, for example particles which will pass through a number 30 sieve and will be retained on a number sieve may be used. The sieve numbers in the specification and claims refag to the U. S. standard sieve numbers a opted by the American Society for Testing Materials.
It is to be understood that alloy steels and irons may be used for the base metal, that-the vertically disposed portions as well as the entire surface of the mold may be coated with the low carbon ferrochromium, that variations in the thickness of the coatings of powder and binder and in the grading of the size of the particles may be made to vary the thickness and character of the alloy coatings, and that the content of chromium and iron may be varied within wide limits without departing from the invention. The ferrochromium may range from about 60% to 97% chromium, the remainder except about 0.5% to 2.0% silicon and about 1.0% to 2.72% carbon being iron.
and claims refers to all the parts of the matrix which are used to give shape to the casting and may include cores as well as the parts of molds which constitute receptacles. Unless otherwise indicated, the term, lining, as used in the specification and claims refers to the coating of powder which is placed on the mold surface.
I claim 1. The method of producing a casting having base metal composed of ferrous alloy and a coating composed of a chromium-containing alloy formed by the union of the cast metal and a lining of ferrochromium powder disposed on the casting mold, which comprises lining the mold with ferrochromium powder containing about 1.0% to about 1.25%
carbon and pouring into the mold ferrous alloy which contains carbon, but not more than 0.5% carbon.
2. A coating for molds adapted to form a chromium-containing alloy surface on a ferrous alloy base metal cast in the mold, which comprises a ferrochromium powder containing carbon, but not more than 2.72% carbon.
3. A coating for molds adapted to form a chromium-containing alloy surface on a ferrous alloy base metal cast in the mold, which comprises a ferrochromium powder containing about 1.0% to about 1.25% carbon.
4. A coatin'g for molds adapted to form a chromium-containing alloy surface on a ferrous alloy base metal cast in the mold, which comprises a ferrochromium powder of such a size that the smallest particles will be retained on about number 40 to number 80 sieves and the largest particles will pass through number 16 to number 20. sieves, said powder containing carbon, but not more than about 2.72% carbon, about 0.5 to 2.0% silicon, about 60% to 97% chromium, and the remainder iron.
In testimony whereof, I aflix my si nature.
JAMES H. CRITCH- TT.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US526551A US1902059A (en) | 1931-03-30 | 1931-03-30 | Production of alloy surface castings |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US526551A US1902059A (en) | 1931-03-30 | 1931-03-30 | Production of alloy surface castings |
Publications (1)
Publication Number | Publication Date |
---|---|
US1902059A true US1902059A (en) | 1933-03-21 |
Family
ID=24097796
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US526551A Expired - Lifetime US1902059A (en) | 1931-03-30 | 1931-03-30 | Production of alloy surface castings |
Country Status (1)
Country | Link |
---|---|
US (1) | US1902059A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2906644A (en) * | 1955-06-22 | 1959-09-29 | Int Alloys Ltd | Method of sealing interstices in refractory materials and apparatus made of the same |
-
1931
- 1931-03-30 US US526551A patent/US1902059A/en not_active Expired - Lifetime
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2906644A (en) * | 1955-06-22 | 1959-09-29 | Int Alloys Ltd | Method of sealing interstices in refractory materials and apparatus made of the same |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5876478A (en) | Metal mold for glass forming | |
US1902059A (en) | Production of alloy surface castings | |
US3414044A (en) | Method of making bimetallic tubular article | |
US3367395A (en) | Method and apparatus for treating molten metals | |
US3598170A (en) | Fluid-mold casting process | |
US3246374A (en) | Process for casting metals into asbestoscontaining mold coating | |
US3158912A (en) | Controlled grain size casting method | |
US2426987A (en) | Mold coating | |
US1965949A (en) | Mold for casting ferrous metals | |
US20180001372A1 (en) | Molding materials for non-ferrous casting | |
US4150709A (en) | Process for applying a coating to a centrifugal casting mold | |
US3993474A (en) | Fluid mold casting slag | |
US1902092A (en) | Production of castings with coatings composed of high-chromium alloys | |
KR102581323B1 (en) | Mold powder and mold coating | |
US2495273A (en) | Method for making sound metal castings | |
US3871875A (en) | Flux composition and a centrifugal casting process using the same | |
US1946069A (en) | Magnesium base die casting alloys | |
US2805152A (en) | Steel alloy welding rod and joint deposit | |
US3110943A (en) | Production of metal ingots, castings and the like | |
Stefanescu | Casting Defects | |
US1570802A (en) | Means for preventing adherence of cast metal to the mold | |
US7896961B2 (en) | Products of the dry-spray type, for the protection of centrifugal casting molds for cast iron pipes | |
Okorafor | Some considerations of the volume shrinkage of aluminium-silicon alloy castings produced in full moulds | |
US3444010A (en) | Fluid-mold casting slag | |
US3257177A (en) | Ferrous castings with siliconized inserts |