CA1111673A - Metal casting with hardened surface layer and method for the manufacture thereof - Google Patents
Metal casting with hardened surface layer and method for the manufacture thereofInfo
- Publication number
- CA1111673A CA1111673A CA301,552A CA301552A CA1111673A CA 1111673 A CA1111673 A CA 1111673A CA 301552 A CA301552 A CA 301552A CA 1111673 A CA1111673 A CA 1111673A
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- CA
- Canada
- Prior art keywords
- metal
- surface layer
- casting
- layer
- foundry
- 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.)
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
- B22D27/20—Measures not previously mentioned for influencing the grain structure or texture; Selection of compositions therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D7/00—Casting ingots, e.g. from ferrous metals
- B22D7/06—Ingot moulds or their manufacture
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Mold Materials And Core Materials (AREA)
- Continuous Casting (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The invention is concerned with a metal casting having a hardened surface layer formed of a casting metal and alloying elements, wherein the hardened surface layer contains grains of a refractory material uniformly distributed through-out its thickness forming inclusions of the refractory material in the hardened surface layer, the alloying elements being such as to impart to the casting metal alloy adequate toughness to retain the inclusions therein; the casting metal and alloying elements extend between the spaces defined between the grains forming the inclusions of the refractory material, and thus retain the inclusions in the surface layer. The metal casting of the invention is manufactured by preparing a foundry paste by mixing together powder alloying elements with a binder and admixing thereto a powder refractory material in combination with a flux; applying a layer of the foundry paste upon the surface of a foundry mould; drying the layer; contacting the layer with a liquor of the same flux; drying the thus formed layer, and filling the foundry mould with overheated molten casting metal such that the molten metal penetrates into the foundry paste layer to retain the grains of refractory material forming the inclusions in the formed hardened surface layer.
The refractory inclusions in the metal castings of the inven-tion which are found in the hardened surface layer make it possible to increase the resistance of the castings to the destructive effects produced by hydrodynamically acting molten metal jet and thus to prolong the service life of the castings.
The invention is concerned with a metal casting having a hardened surface layer formed of a casting metal and alloying elements, wherein the hardened surface layer contains grains of a refractory material uniformly distributed through-out its thickness forming inclusions of the refractory material in the hardened surface layer, the alloying elements being such as to impart to the casting metal alloy adequate toughness to retain the inclusions therein; the casting metal and alloying elements extend between the spaces defined between the grains forming the inclusions of the refractory material, and thus retain the inclusions in the surface layer. The metal casting of the invention is manufactured by preparing a foundry paste by mixing together powder alloying elements with a binder and admixing thereto a powder refractory material in combination with a flux; applying a layer of the foundry paste upon the surface of a foundry mould; drying the layer; contacting the layer with a liquor of the same flux; drying the thus formed layer, and filling the foundry mould with overheated molten casting metal such that the molten metal penetrates into the foundry paste layer to retain the grains of refractory material forming the inclusions in the formed hardened surface layer.
The refractory inclusions in the metal castings of the inven-tion which are found in the hardened surface layer make it possible to increase the resistance of the castings to the destructive effects produced by hydrodynamically acting molten metal jet and thus to prolong the service life of the castings.
Description
.~ .
The present invention relates to metal castings having a hardened surface la~er and to a method for the manufacture thereof.
The invention can be advantageously used in the manufacture of parts and units of metallurgical and foundry equipment operating in contact with molten metal, e.g., in making moulds for casting ingots ~rom various metals and alloys.
The invention can also be used to advantage for the manufacture of parts and units of equipment intended for service under abrasive wear conditions in any aggressive media.
It is common knowledge that parts of metallurgical equipment often fail in service at places where a jet of molten metal impinges thereupon or at points of contact with - an abrasive medium. In such instances, a most effective and economically advantageous way to enhance the durability of castings is to provide a hardened surface layer on the working surfaces thereof.
There are known metal castings with a hardened sur-~0 face layer, e.g., bimetal castings and castings with a metal-loceramic and surface-alloyed layers.
Bimetal castings are manufactured by contacting one metal with another or by placing an insert of a metal in a ~` foundry mould and filling it with another metal, resulting in the fusion of the metals and the formation of a hardened surface layer.
Bimetal castings have a higher toughness and chemical resistance, but in service they tend to develop high internal stresses at the interface of the metals, which cause cracking, chipping or separation of one metal from another, due to a substantial concentration gradient in chemical composition within a relatively small transitional zone.
In additiong the hardened layer in bimetal castings f~ils to adequately resist the action of a jet of molten metal or abrasive wear.
Casting~ with a metalloceramic hardened layer are obtained by applying to the surface of a oundry mould a coat-ing of a foundry paste or of a paint composed of a mixture of powders susceptible to fritting, and subsequently ~illing the folmdry mould with a casting metalO The contact between the molten casting metal with the coating of the foundry paste or paint results in the fritting of the coating and its bonding with the surface of the casting metal.
There is known, for example, a paint composed of a mixture of refractory components, such as corundum, bentonite and asbestos with soluble glass as a binder. This paint readily frits on the working surface of cast iron ingot moulds in the process of their manufacture.
Metalloceramic layer is known to enhance the chemical resistance of the ingot moulds~ but because of its small thick-ness (0.5 to 2.0 mm) the resistance of such layer to the ~` erosive action of molten metal is low, hence the ingot moulds have a short service life.
In addition, the metalloceramic layer has a relatively ~: low refractoriness and a poor resistance to burn-back and erosive action by molten metaln The reason is that the refrac-tory components in the paint is a mixture of chemical compounds of different nature, which at high metal casting temperatures interact not only with one another, but with the oxides of the metal being cast, forming low-melting compositions which bring about rapid failure of the metalloceramics.
There are also known metal castings with a hardened - s~rface layer formed of an alloy composed of the casting metal ~~ _z_ and alloying elements.
In known castings from ferrous metals, the alloying elements are generally ferroalloys.
~ he prior art method for manufacturing such castings comprises preparing a foundry paste by mixing powder alloying elements with a binder, applying a coating of said paste to the surface of a foundry mould, drying the coating, and sub-sequently filling the foundry mould with a casting metal.
In the course of filling the foundry mould with the casting metal the latter interacts with the coating of the foundry paste, forming a hardened surface layer on the casting.
A disadvantage of metal castings with such hardened layer is a relatively poor thermal and chemical resistance thereof, since like a metalloceramic surface layer, it is fairly rapidly eroded by a jet of molten metal.
It has been impossible to improve the wear resistance of such castings, since an increase in the amount of solid and wear resistant inclusions of carbides of alloying elements adds to the brittleness of the hardened surface layer and the spalling thereof.
Moreover, the manufacture of castings with a hardened surface layer with the use of refractory ferroalloys as alloy-ing elements poses many practical problems.
It is therefore an o~ject of the present invention to provide metal castings having a hardened surface layer and a method for the manufacture thereof, which will substantially improve the thermal and chernical resistance of the hardened surface layer of castings in the course of the interaction thereof with molten metal9 thus substantially increasing the durability of the castings as a whole.
Another object of the invention i5 to enhance -the wear resistance of the hardened surface layer in the course of its ,.~
1~ -3-G'7~
abrasive wear in any aggressive media.
In accordance with the present invention, there i~
provided a metal casting having a hardened surface layer formed of a casting metal and alloying elements, wherein the hardened surface layer contains grains of a refractory material uniform-ly distributed throughout its thic~ness forming inclusions of the refractory material in said hardened surface layer, the alloying elements being such as to impart to the casting metal alloy adequate toughness to retain the inclusions therein.
The casting metal and alloying elements extend between the spaces de~ined between the grains forming the inclusions of the refractory material and thereby retain the inclusions in the surface layer.
The provision of a refractory filler in the hardened surface layer enhances the thermal and chemical resistance of the layer and thus increases the durability of castings 9 the viscous alloyed melt firmly retaining the inclusions of the refractory filler.
The refractory filler in a cast iron casting is preferably corundum, and the alloying element in the hardened surface layer, nickel.
As is known9 corundum(a crystalline alurninium oxide) has high chemical resistance, refractoriness (a melting point of 2200C) and hardness, being second in hardness only to diamond, and, therefore, the presence of corundum inclusions in the hardened surface layer of castings substantially increa-ses the wear resistance and the resistance against erosion by molten metal.
The presence of nickel in the hardened surface layer of cast iron castings, in addition to increasing the toughness of this layer for retaining corundum inclusions therein, enhances the strength and chemical resistance of the hardened . . ~ ~ t ~
~ -4-L Ei7~
surface layer, which ultimately ensures a substantial increase in the durability of cast iron parts operating in contact with molten metal, under dynamic loads and in conditions of abrasive wear in aggressive media.
In addition, nickel wets refractory materials, better than any other alloying element~ and9 therefore, a nickel-alloyed cast iron will best form a hardened layer with corundum as a refractory filler and best retain its inclusions~
By combining these properties of nickel and corundum, it becomes possible to ohtain in cast iron castings a hardened surface layer having high operating characteristics when in contact with molten metal and under severe abrasive wear conditions, thus providing substantial increase in the durabi-lity of cast iron parts.
The present invention also provides a method for manufacturing metal castings having a hardened surface layer as previously defined, which comprises preparing a foundry paste by mixing together powder alloying elements with a binder and admixing thereto a powder refractory material in combination with a flux applying a layer of the foundry paste upon the surface of a foundry mould drying the layer contacting the layer with a liquor of the same flux; drying the thus formed layer, and filling the foundry mould with overheated molten casting metal such that the molten metal penetrates into the foundry paste layer to retain the grains of refractory material forming the inclusions in the formed hardened surface layer.
Introducing flux into the foundry paste and applying a coat thereof to the foundry paste surface, followed by drying, substantially improve the wetting of the inclu.sions of the refractory filler contained in the foundry paste by the molten cast-ng metal, with the latter penetrating throughout the full depth of the porous foundry paste which is heated by ~ . ", ~ -5-7~
the overheated molten metal.
Such method for manufacturing castings with a hardened - surface layer makes it possible to substantially increase the thickness of this layer and improves its quality.
It is preferred to use nickel as the alloying ele-ment in the foundry paste for the manufacture of metal cast-ings from cast iron, corundum as the refractory ~iller, soluble ~lass as the binder 9 the flux being a mixture of metal salts in the following proportions (in weight percent):
sodium chloride (~aCl) 35 to ~0 potassium chloride (KCl) 35 to 40 zinc chloride (ZnC12) 8 to 10 cesium fluoride (CsF) 8 to 10 sodium borofluoride (NaBF4) 5 to 9 and the foundry paste components being taken in the following proportions (in weight percent):
nickel 20 to 70 corundum 20 to 60 ~lux 0.1 to 2.0 soluble glass 3 to 8~
The flux of such chemical composition has been chosen by reason of its being based on sodium chloride and potassium chloride which determine its fusibility and viscosity. Zinc chloride lowers the flux melting point and provides a refining gas atmosphere. Cesium fluoride is a surfactant with respect to cast iron readily dissolving aluminium oxide (corundum).
Sodium borofluoride is an active additive to aluminium oxide capable of chemically interacting therewith.
; All the above properties of the flux contribute to the formation on the surface of the corundum inclusions, of an interlayer of a substance wettable by molten cast iron.
The invention is illustrated by way of exarnple in the accompanying drawings, in which:
` ~ -6-'73 the accompanying drawings, in which:
FIG. 1 is a diagrammatic top view of a metal casting in the form of an ingot mould of cast iron with a hardened surface layer, according to the invention, FIG. 2 is a cross-section taken along line II-II
o~ FIG. 1, FIG. 3 is an enlarged cross section of an ingot mould surface layer line III-III of FIG. 2;
FIG. 4 is a diagram of the variation of the marginal angle o~ wetting of the foundry paste by the cast iron of an ingot mould as a function of the sodium borofluoride (~aBF43 content in the fl~, FIG. 5 is a diagram of the variation of the marginal ; an~le of wetting of the foundry paste by the cast iron of an ingot mould as a function of the cesium fluoride ~CsF) content in the flux, --FIG. 6 is a diagram illustrating the relationship between the time period re~uired for a drop of ca5t iron to spread over the surface of the foundry paste and the chemical composition of the fluxo To illustrate the invention, a metal casting with a hardened surface layer is exemplified by an ingot mould for manufacturing anodes of nickel alloys.
It is common ]cnowledge that ingot moulds are subjected in service to considerable temperature gradients and at the same time to the hydrodynamic action thereupon of a jet of molten metal.
In the embodiment of the invention illustrated in Figures 1 and 2, the ingot mould has a body 1 of cast iron and is provided with a cavity 2 for pouring molten metal.
- The bottom of the cavity has a hardened surface layer 3 in the form of an alloy of cast iron with an alloying element.
The hardened surface layer 3 of the ingot mould contains uniformly distributed therein inclusions of a refractory filler which is corundum (aluminium oxide A1~03) in the form of grains 4, as best shown in Figuxe 3. The alloying element in the hardened surface layer 3 is nickel, the alloy thereof with the cast iron o~ the body 1 having adequate toughness to retaln therein the grains of corundum.
Practice has shown that the most effective alloying element in the hardened surface layer 3 of an ingot mould is ; 10 that which is contained in the metal to be poured therein.
Therefore, an ingot mould for manufacturing anodes of nickel alloys is realized with nickel as the alloying element7 since it will not interact with the nickel contained in alloy to be poured in the ingot moulds, thus enhancing the chemical resis-tance of the ingot mould hardened surface layer 3.
The concentration of nickel in the hardened surface layer 3 decreases gradually from its external surface inwardly of the ingot mould body 1, as is schematically shown on Fig. 3 wherein the nickel inclusions 5 are shown in small dots~ As mentioned, there arise no substantial internal stresses at the boundary between the ingot mould body 1 and its hardened surface layer 3, thu~ ensuring a strong mutual bond therebetween.
The surface layer 3 of the ingot mould contacts the nickel alloy in the course of pouringl subsequent crystalli-zation and solidification occurring generally throuyh the grains 4 of the corundum which occupy in the body of the hardened surface layer 3 more than 50% of its volume. These corundum grains possess substantial dimensions (i.e. have a diameter ranging from 0.2 to 3.0 mm) and the requisite propertles to play a determining part in the process of the interaction between the ingot and the ingot mould, since they take up the hydrodynamic action of the jet of molten alloy9 affect ~ubstan-, ~
~ y -8-'''' 67~
tially the h~at and the mass transfer and the removal of heat, thus preventing the ingot mould metal from fusing to the ingot and protecting against abrasive wear.
As the jet of molten metal comes into contact with the hardened surface layer 3 of the ingot mould and the projeCt-ing corundum grains ~ thereon, the latter break up the turbulent character of motion of the jet9 giving rise to a laminar layer of molten alloy between the corund~ grains 4. This layer acts as a "buffer" which, once formed, takes up subsequently the impact of the jet of molten alloy and thus protects the hardened surface layer 3 of the ingo~ mould against the thermal, m~chanical and chemical action of the jet of molten metal.
Corundum grains 4 having less than 0.2 mm in diameter have no appreciable effect, whereas corundum inclusions having a diameter larger than 3 mm fail to resist the mechanical action of molten metal and tend to spall under the jet of molten metal.
The fact that the failling jet of molten metal impin- -ges not upon the hardened surface layer 3 of the ingot mould, but upon the laminar layer of metal, flowing subsequently thereon, greatly affects the processes of heat transfer9 solu-tion and chemical action. This is also influenced to a great degree by the large size of the corundum grains 4, as the solution and the heat transfer processes in the laminar layer of a molten metal are proportional to the second power of the dimensional factor.
Heat is transferred from the surface of a solidified metal ingot to the hardened surface layer 3 of the ingot moulcl by radiation between the corundum grains 4 ancl by heat conduc-tivity across the corundum grains 4 The amount of ra~iatedheat is also proportional to the second power of the distance b ~ een the radiating and the absorbing bodies, i.e., to the .
diameter of the corundum grains 4. Corundum inclusions also contri~ute to uniform heating of the ingot mould because of their substantial resis-tance to heat removal.
Thus~ the grains 4 of pure corundum, completely free from mineral admixtures, owing to their high refractoriness and chemical neutrality with respect to metal, impart to the hardened surface layer 3 of the mould both high streng-th and resistance to the destructive effects produced by hydrodynami-cally acting molten metal jet, whereas the high-alloy matrix of the surface layer 3 makes it resistant to thermal and chemical attack.
It should also be noted ~hat when such ingot moulds are used for casting other alloys they prove to be no less durable, since anodic nickel possesses, as compared to other alloys, a high specific mass and a high capacity for dissolv-ing oxygen (up to 2%). In particular, ingot moulds for cast-ing ingots from ferrous metals and alloys may be manufactured using fillers such as chromite and magnesite which are cheaper, ; but not much inferior to corundum in other properties, and alloying elements such as manganese and chromium which enhance the resistance and the strength of the metal matrix of the ingot mould hardened surface layer.
A method for manufacturing cast iron ingot moulds with a hardened surface layer 3 includes the preparation of a foundry paste by mixing powder nickel (i.e., the alloying ele-ment) with soluble glass as binder, the application of a layer of the foundry paste upon the surface of the foundry mould ` (not shown on the drawing~, the drying of the layer and the subsequent filling of the foundry mould with molten cast iron.
~he preparation of the foundry paste lnvolves also the introduction therein of powder corundum (i.e~, the refrac-~' -10-'`, :
tory filler) in combination with a flux which is a mixture o-f sodium, potassium, zinc and cesium salts in the following pro-portions (% by weight):
sodium chloride (NaCl) 35 - 40 potassium chloride (KCl) 35 - ~0 zinc chloride (ZnC12) 8 - 10 cesium fluoride (CsF) 8 - 10 sodium borofluoride (NaBF4) 5 - 9, the proportions of the foundry paste components being as follows 10 (% by weight):
nickel 20 - 70 corundum 20 - 60 flux 0.1 - 2.0 soluble glass 3 - 8.
After a layer of this foundry paste has been applied upon the surface of a foundry mould for casting the ingot mould and has dried, it is contacted with a liquor of the same flux and dried again.
The flux of the above composition affects the nature of the interaction of the molten cast iron in the process of its pouring into the foundry mould with the corundum grains incorporated in the foundry paste. By spreading itself over the surface of corundum grains, the flux forms a film of an active substance making it easier for the molten iron to wet the surface of the corundum grains 4, and, therefore, to pene-trate into the pores of the foundry paste between the grains 4 of corundum and simultaneously interact with the nickel.
The foundry mould is filled with overheated molten iron to ensure the heating of the foundry paste layer and to improve the impregnation thereof with cast iron. The tempera-ture to which the cast iron is overheated depends on the thick-ness of the casting and that of the layer of the foundry paste.
.
The above manufacturing procedure results in the formation on an ingot mould of a hardened surface layer in the form of a resistant cast iron and nickel alloy incorporating uniformly distributed corundum inclusions.
This method of manu~acturing metal castings provides on the metal casting a hardened surface layer 3 having a thick-ness ranging from 0.05 to 0.2 of the thickness of the cast-ing body, which is much greater than that of hardened surface layers obtainable by any of the prior art methods.
In practice, the hardened surface layer 3 in ingot moulds manufactured by the aforesaid method extends up to 15 mm in depth.
In addition, the proposed method substantially simplifies the production process for manufacturing castings with a hardened surface layer and makes it possible to widen the range of castings being manufactured and improve the ~uality thereof.
Thus, the resistance of the hardened surface layer 3 of a cast iron ingot mould manufactured by the proposed method to the hydrodynamic erosion by a molten nickel alloy is three times higher, and the wear resistance in abrasive medium is substantially greater than in known surface-alloyed castings.
In order to more clearly understand the method for manufacturing metal castings with a hardened surface layer, as proposed by the invention 9 it will now be described by way of - example with reference to a production process for manufacturing a cast iron mould for casting anodes from nickel alloys.
A foundry paste composed of a mixture of powders of ~ nickel (grain size of 0u0063 mm)~ of corundum (grain size of ; 30 0.1 to 2.0 mm) and of soluble glass as a binder, is first prepa-` red, the proportion of the components being as follows (% by weight):
` .~
7~
nickel 55 corundum 40 soluble glass 5.
Next, the foundry paste is thoroughly stirred, then mixed with a fine powder ~lux in the amount of 0.5 to 1%
depending on the corundum grain size.
The flux is a mixture of sodium, potas~ium9 zinc and cesium salts in the following proportions (% by weight):
sodium chloride (NaCl)40 10 potassium chloride (KCl) 35 zinc chloride (ZnC12) 10 cesium fluoride (CsF~ 10 sodium borofluoride (~aBF4) 5.
After processing with the flux, the foundry paste is stirred again, applied in a layer 8 mm thick upon the foundry mould surface and dried at a temperature between 150 and 200C.
After drying, the foundry paste while still hot is contacted with a 20% liquor of the same flux and dried again at a tempe-rature between 50 and 150C.
The foundry mould is next assembled and filled with molten cast iron heated to 1390-1400C~ Once the cast iron has solidified, its working surface is formed with a hardene~ sur-face metalloceramic layer 10 mm thick composed of a high-alloy nickel cast iron with inclusions of corundum, uniformly distri-buted therein, the corundum grains occupyingmore than 50% of the volume of the surface layer.
The following table illustrates the durability of cast iron ingot mould as a function of the foundry paste compo-sition.
., ~ 13-.
~3 ;
Item Foundry paste composition Ingot mould ~o. (% by mass) durability ________ ________________ ________.__ powder powder ~lux binder number % as com- Quality of corun- nickel solub- of pour- pared to working dum le ings non-har- surface of glass dened in- ingot moulds got moulds . .
1 20 74.7 0~8 4.5 58 120 5urface of metal
The present invention relates to metal castings having a hardened surface la~er and to a method for the manufacture thereof.
The invention can be advantageously used in the manufacture of parts and units of metallurgical and foundry equipment operating in contact with molten metal, e.g., in making moulds for casting ingots ~rom various metals and alloys.
The invention can also be used to advantage for the manufacture of parts and units of equipment intended for service under abrasive wear conditions in any aggressive media.
It is common knowledge that parts of metallurgical equipment often fail in service at places where a jet of molten metal impinges thereupon or at points of contact with - an abrasive medium. In such instances, a most effective and economically advantageous way to enhance the durability of castings is to provide a hardened surface layer on the working surfaces thereof.
There are known metal castings with a hardened sur-~0 face layer, e.g., bimetal castings and castings with a metal-loceramic and surface-alloyed layers.
Bimetal castings are manufactured by contacting one metal with another or by placing an insert of a metal in a ~` foundry mould and filling it with another metal, resulting in the fusion of the metals and the formation of a hardened surface layer.
Bimetal castings have a higher toughness and chemical resistance, but in service they tend to develop high internal stresses at the interface of the metals, which cause cracking, chipping or separation of one metal from another, due to a substantial concentration gradient in chemical composition within a relatively small transitional zone.
In additiong the hardened layer in bimetal castings f~ils to adequately resist the action of a jet of molten metal or abrasive wear.
Casting~ with a metalloceramic hardened layer are obtained by applying to the surface of a oundry mould a coat-ing of a foundry paste or of a paint composed of a mixture of powders susceptible to fritting, and subsequently ~illing the folmdry mould with a casting metalO The contact between the molten casting metal with the coating of the foundry paste or paint results in the fritting of the coating and its bonding with the surface of the casting metal.
There is known, for example, a paint composed of a mixture of refractory components, such as corundum, bentonite and asbestos with soluble glass as a binder. This paint readily frits on the working surface of cast iron ingot moulds in the process of their manufacture.
Metalloceramic layer is known to enhance the chemical resistance of the ingot moulds~ but because of its small thick-ness (0.5 to 2.0 mm) the resistance of such layer to the ~` erosive action of molten metal is low, hence the ingot moulds have a short service life.
In addition, the metalloceramic layer has a relatively ~: low refractoriness and a poor resistance to burn-back and erosive action by molten metaln The reason is that the refrac-tory components in the paint is a mixture of chemical compounds of different nature, which at high metal casting temperatures interact not only with one another, but with the oxides of the metal being cast, forming low-melting compositions which bring about rapid failure of the metalloceramics.
There are also known metal castings with a hardened - s~rface layer formed of an alloy composed of the casting metal ~~ _z_ and alloying elements.
In known castings from ferrous metals, the alloying elements are generally ferroalloys.
~ he prior art method for manufacturing such castings comprises preparing a foundry paste by mixing powder alloying elements with a binder, applying a coating of said paste to the surface of a foundry mould, drying the coating, and sub-sequently filling the foundry mould with a casting metal.
In the course of filling the foundry mould with the casting metal the latter interacts with the coating of the foundry paste, forming a hardened surface layer on the casting.
A disadvantage of metal castings with such hardened layer is a relatively poor thermal and chemical resistance thereof, since like a metalloceramic surface layer, it is fairly rapidly eroded by a jet of molten metal.
It has been impossible to improve the wear resistance of such castings, since an increase in the amount of solid and wear resistant inclusions of carbides of alloying elements adds to the brittleness of the hardened surface layer and the spalling thereof.
Moreover, the manufacture of castings with a hardened surface layer with the use of refractory ferroalloys as alloy-ing elements poses many practical problems.
It is therefore an o~ject of the present invention to provide metal castings having a hardened surface layer and a method for the manufacture thereof, which will substantially improve the thermal and chernical resistance of the hardened surface layer of castings in the course of the interaction thereof with molten metal9 thus substantially increasing the durability of the castings as a whole.
Another object of the invention i5 to enhance -the wear resistance of the hardened surface layer in the course of its ,.~
1~ -3-G'7~
abrasive wear in any aggressive media.
In accordance with the present invention, there i~
provided a metal casting having a hardened surface layer formed of a casting metal and alloying elements, wherein the hardened surface layer contains grains of a refractory material uniform-ly distributed throughout its thic~ness forming inclusions of the refractory material in said hardened surface layer, the alloying elements being such as to impart to the casting metal alloy adequate toughness to retain the inclusions therein.
The casting metal and alloying elements extend between the spaces de~ined between the grains forming the inclusions of the refractory material and thereby retain the inclusions in the surface layer.
The provision of a refractory filler in the hardened surface layer enhances the thermal and chemical resistance of the layer and thus increases the durability of castings 9 the viscous alloyed melt firmly retaining the inclusions of the refractory filler.
The refractory filler in a cast iron casting is preferably corundum, and the alloying element in the hardened surface layer, nickel.
As is known9 corundum(a crystalline alurninium oxide) has high chemical resistance, refractoriness (a melting point of 2200C) and hardness, being second in hardness only to diamond, and, therefore, the presence of corundum inclusions in the hardened surface layer of castings substantially increa-ses the wear resistance and the resistance against erosion by molten metal.
The presence of nickel in the hardened surface layer of cast iron castings, in addition to increasing the toughness of this layer for retaining corundum inclusions therein, enhances the strength and chemical resistance of the hardened . . ~ ~ t ~
~ -4-L Ei7~
surface layer, which ultimately ensures a substantial increase in the durability of cast iron parts operating in contact with molten metal, under dynamic loads and in conditions of abrasive wear in aggressive media.
In addition, nickel wets refractory materials, better than any other alloying element~ and9 therefore, a nickel-alloyed cast iron will best form a hardened layer with corundum as a refractory filler and best retain its inclusions~
By combining these properties of nickel and corundum, it becomes possible to ohtain in cast iron castings a hardened surface layer having high operating characteristics when in contact with molten metal and under severe abrasive wear conditions, thus providing substantial increase in the durabi-lity of cast iron parts.
The present invention also provides a method for manufacturing metal castings having a hardened surface layer as previously defined, which comprises preparing a foundry paste by mixing together powder alloying elements with a binder and admixing thereto a powder refractory material in combination with a flux applying a layer of the foundry paste upon the surface of a foundry mould drying the layer contacting the layer with a liquor of the same flux; drying the thus formed layer, and filling the foundry mould with overheated molten casting metal such that the molten metal penetrates into the foundry paste layer to retain the grains of refractory material forming the inclusions in the formed hardened surface layer.
Introducing flux into the foundry paste and applying a coat thereof to the foundry paste surface, followed by drying, substantially improve the wetting of the inclu.sions of the refractory filler contained in the foundry paste by the molten cast-ng metal, with the latter penetrating throughout the full depth of the porous foundry paste which is heated by ~ . ", ~ -5-7~
the overheated molten metal.
Such method for manufacturing castings with a hardened - surface layer makes it possible to substantially increase the thickness of this layer and improves its quality.
It is preferred to use nickel as the alloying ele-ment in the foundry paste for the manufacture of metal cast-ings from cast iron, corundum as the refractory ~iller, soluble ~lass as the binder 9 the flux being a mixture of metal salts in the following proportions (in weight percent):
sodium chloride (~aCl) 35 to ~0 potassium chloride (KCl) 35 to 40 zinc chloride (ZnC12) 8 to 10 cesium fluoride (CsF) 8 to 10 sodium borofluoride (NaBF4) 5 to 9 and the foundry paste components being taken in the following proportions (in weight percent):
nickel 20 to 70 corundum 20 to 60 ~lux 0.1 to 2.0 soluble glass 3 to 8~
The flux of such chemical composition has been chosen by reason of its being based on sodium chloride and potassium chloride which determine its fusibility and viscosity. Zinc chloride lowers the flux melting point and provides a refining gas atmosphere. Cesium fluoride is a surfactant with respect to cast iron readily dissolving aluminium oxide (corundum).
Sodium borofluoride is an active additive to aluminium oxide capable of chemically interacting therewith.
; All the above properties of the flux contribute to the formation on the surface of the corundum inclusions, of an interlayer of a substance wettable by molten cast iron.
The invention is illustrated by way of exarnple in the accompanying drawings, in which:
` ~ -6-'73 the accompanying drawings, in which:
FIG. 1 is a diagrammatic top view of a metal casting in the form of an ingot mould of cast iron with a hardened surface layer, according to the invention, FIG. 2 is a cross-section taken along line II-II
o~ FIG. 1, FIG. 3 is an enlarged cross section of an ingot mould surface layer line III-III of FIG. 2;
FIG. 4 is a diagram of the variation of the marginal angle o~ wetting of the foundry paste by the cast iron of an ingot mould as a function of the sodium borofluoride (~aBF43 content in the fl~, FIG. 5 is a diagram of the variation of the marginal ; an~le of wetting of the foundry paste by the cast iron of an ingot mould as a function of the cesium fluoride ~CsF) content in the flux, --FIG. 6 is a diagram illustrating the relationship between the time period re~uired for a drop of ca5t iron to spread over the surface of the foundry paste and the chemical composition of the fluxo To illustrate the invention, a metal casting with a hardened surface layer is exemplified by an ingot mould for manufacturing anodes of nickel alloys.
It is common ]cnowledge that ingot moulds are subjected in service to considerable temperature gradients and at the same time to the hydrodynamic action thereupon of a jet of molten metal.
In the embodiment of the invention illustrated in Figures 1 and 2, the ingot mould has a body 1 of cast iron and is provided with a cavity 2 for pouring molten metal.
- The bottom of the cavity has a hardened surface layer 3 in the form of an alloy of cast iron with an alloying element.
The hardened surface layer 3 of the ingot mould contains uniformly distributed therein inclusions of a refractory filler which is corundum (aluminium oxide A1~03) in the form of grains 4, as best shown in Figuxe 3. The alloying element in the hardened surface layer 3 is nickel, the alloy thereof with the cast iron o~ the body 1 having adequate toughness to retaln therein the grains of corundum.
Practice has shown that the most effective alloying element in the hardened surface layer 3 of an ingot mould is ; 10 that which is contained in the metal to be poured therein.
Therefore, an ingot mould for manufacturing anodes of nickel alloys is realized with nickel as the alloying element7 since it will not interact with the nickel contained in alloy to be poured in the ingot moulds, thus enhancing the chemical resis-tance of the ingot mould hardened surface layer 3.
The concentration of nickel in the hardened surface layer 3 decreases gradually from its external surface inwardly of the ingot mould body 1, as is schematically shown on Fig. 3 wherein the nickel inclusions 5 are shown in small dots~ As mentioned, there arise no substantial internal stresses at the boundary between the ingot mould body 1 and its hardened surface layer 3, thu~ ensuring a strong mutual bond therebetween.
The surface layer 3 of the ingot mould contacts the nickel alloy in the course of pouringl subsequent crystalli-zation and solidification occurring generally throuyh the grains 4 of the corundum which occupy in the body of the hardened surface layer 3 more than 50% of its volume. These corundum grains possess substantial dimensions (i.e. have a diameter ranging from 0.2 to 3.0 mm) and the requisite propertles to play a determining part in the process of the interaction between the ingot and the ingot mould, since they take up the hydrodynamic action of the jet of molten alloy9 affect ~ubstan-, ~
~ y -8-'''' 67~
tially the h~at and the mass transfer and the removal of heat, thus preventing the ingot mould metal from fusing to the ingot and protecting against abrasive wear.
As the jet of molten metal comes into contact with the hardened surface layer 3 of the ingot mould and the projeCt-ing corundum grains ~ thereon, the latter break up the turbulent character of motion of the jet9 giving rise to a laminar layer of molten alloy between the corund~ grains 4. This layer acts as a "buffer" which, once formed, takes up subsequently the impact of the jet of molten alloy and thus protects the hardened surface layer 3 of the ingo~ mould against the thermal, m~chanical and chemical action of the jet of molten metal.
Corundum grains 4 having less than 0.2 mm in diameter have no appreciable effect, whereas corundum inclusions having a diameter larger than 3 mm fail to resist the mechanical action of molten metal and tend to spall under the jet of molten metal.
The fact that the failling jet of molten metal impin- -ges not upon the hardened surface layer 3 of the ingot mould, but upon the laminar layer of metal, flowing subsequently thereon, greatly affects the processes of heat transfer9 solu-tion and chemical action. This is also influenced to a great degree by the large size of the corundum grains 4, as the solution and the heat transfer processes in the laminar layer of a molten metal are proportional to the second power of the dimensional factor.
Heat is transferred from the surface of a solidified metal ingot to the hardened surface layer 3 of the ingot moulcl by radiation between the corundum grains 4 ancl by heat conduc-tivity across the corundum grains 4 The amount of ra~iatedheat is also proportional to the second power of the distance b ~ een the radiating and the absorbing bodies, i.e., to the .
diameter of the corundum grains 4. Corundum inclusions also contri~ute to uniform heating of the ingot mould because of their substantial resis-tance to heat removal.
Thus~ the grains 4 of pure corundum, completely free from mineral admixtures, owing to their high refractoriness and chemical neutrality with respect to metal, impart to the hardened surface layer 3 of the mould both high streng-th and resistance to the destructive effects produced by hydrodynami-cally acting molten metal jet, whereas the high-alloy matrix of the surface layer 3 makes it resistant to thermal and chemical attack.
It should also be noted ~hat when such ingot moulds are used for casting other alloys they prove to be no less durable, since anodic nickel possesses, as compared to other alloys, a high specific mass and a high capacity for dissolv-ing oxygen (up to 2%). In particular, ingot moulds for cast-ing ingots from ferrous metals and alloys may be manufactured using fillers such as chromite and magnesite which are cheaper, ; but not much inferior to corundum in other properties, and alloying elements such as manganese and chromium which enhance the resistance and the strength of the metal matrix of the ingot mould hardened surface layer.
A method for manufacturing cast iron ingot moulds with a hardened surface layer 3 includes the preparation of a foundry paste by mixing powder nickel (i.e., the alloying ele-ment) with soluble glass as binder, the application of a layer of the foundry paste upon the surface of the foundry mould ` (not shown on the drawing~, the drying of the layer and the subsequent filling of the foundry mould with molten cast iron.
~he preparation of the foundry paste lnvolves also the introduction therein of powder corundum (i.e~, the refrac-~' -10-'`, :
tory filler) in combination with a flux which is a mixture o-f sodium, potassium, zinc and cesium salts in the following pro-portions (% by weight):
sodium chloride (NaCl) 35 - 40 potassium chloride (KCl) 35 - ~0 zinc chloride (ZnC12) 8 - 10 cesium fluoride (CsF) 8 - 10 sodium borofluoride (NaBF4) 5 - 9, the proportions of the foundry paste components being as follows 10 (% by weight):
nickel 20 - 70 corundum 20 - 60 flux 0.1 - 2.0 soluble glass 3 - 8.
After a layer of this foundry paste has been applied upon the surface of a foundry mould for casting the ingot mould and has dried, it is contacted with a liquor of the same flux and dried again.
The flux of the above composition affects the nature of the interaction of the molten cast iron in the process of its pouring into the foundry mould with the corundum grains incorporated in the foundry paste. By spreading itself over the surface of corundum grains, the flux forms a film of an active substance making it easier for the molten iron to wet the surface of the corundum grains 4, and, therefore, to pene-trate into the pores of the foundry paste between the grains 4 of corundum and simultaneously interact with the nickel.
The foundry mould is filled with overheated molten iron to ensure the heating of the foundry paste layer and to improve the impregnation thereof with cast iron. The tempera-ture to which the cast iron is overheated depends on the thick-ness of the casting and that of the layer of the foundry paste.
.
The above manufacturing procedure results in the formation on an ingot mould of a hardened surface layer in the form of a resistant cast iron and nickel alloy incorporating uniformly distributed corundum inclusions.
This method of manu~acturing metal castings provides on the metal casting a hardened surface layer 3 having a thick-ness ranging from 0.05 to 0.2 of the thickness of the cast-ing body, which is much greater than that of hardened surface layers obtainable by any of the prior art methods.
In practice, the hardened surface layer 3 in ingot moulds manufactured by the aforesaid method extends up to 15 mm in depth.
In addition, the proposed method substantially simplifies the production process for manufacturing castings with a hardened surface layer and makes it possible to widen the range of castings being manufactured and improve the ~uality thereof.
Thus, the resistance of the hardened surface layer 3 of a cast iron ingot mould manufactured by the proposed method to the hydrodynamic erosion by a molten nickel alloy is three times higher, and the wear resistance in abrasive medium is substantially greater than in known surface-alloyed castings.
In order to more clearly understand the method for manufacturing metal castings with a hardened surface layer, as proposed by the invention 9 it will now be described by way of - example with reference to a production process for manufacturing a cast iron mould for casting anodes from nickel alloys.
A foundry paste composed of a mixture of powders of ~ nickel (grain size of 0u0063 mm)~ of corundum (grain size of ; 30 0.1 to 2.0 mm) and of soluble glass as a binder, is first prepa-` red, the proportion of the components being as follows (% by weight):
` .~
7~
nickel 55 corundum 40 soluble glass 5.
Next, the foundry paste is thoroughly stirred, then mixed with a fine powder ~lux in the amount of 0.5 to 1%
depending on the corundum grain size.
The flux is a mixture of sodium, potas~ium9 zinc and cesium salts in the following proportions (% by weight):
sodium chloride (NaCl)40 10 potassium chloride (KCl) 35 zinc chloride (ZnC12) 10 cesium fluoride (CsF~ 10 sodium borofluoride (~aBF4) 5.
After processing with the flux, the foundry paste is stirred again, applied in a layer 8 mm thick upon the foundry mould surface and dried at a temperature between 150 and 200C.
After drying, the foundry paste while still hot is contacted with a 20% liquor of the same flux and dried again at a tempe-rature between 50 and 150C.
The foundry mould is next assembled and filled with molten cast iron heated to 1390-1400C~ Once the cast iron has solidified, its working surface is formed with a hardene~ sur-face metalloceramic layer 10 mm thick composed of a high-alloy nickel cast iron with inclusions of corundum, uniformly distri-buted therein, the corundum grains occupyingmore than 50% of the volume of the surface layer.
The following table illustrates the durability of cast iron ingot mould as a function of the foundry paste compo-sition.
., ~ 13-.
~3 ;
Item Foundry paste composition Ingot mould ~o. (% by mass) durability ________ ________________ ________.__ powder powder ~lux binder number % as com- Quality of corun- nickel solub- of pour- pared to working dum le ings non-har- surface of glass dened in- ingot moulds got moulds . .
1 20 74.7 0~8 4.5 58 120 5urface of metal
2 50 44.7 0.8 4.5 156 300 Surface of metal clear and smooth
3 70 24.7 0.8 4.5 50 106 Areas of non assimilated foundry paste Referring to the Table, it is seen that less than 20%
of corund~ has no effect upon the increase in the resistance of the hardened surface layer to erosion by molten alloys, whereas 70% makes the formation of the layer difficult.
Studies of various compositions of flux for process-ing corundum containing foundry pastes covered ones based on a mixture of sodium chloride (NaCl) and potassium chloride (KCl) in a mass ratio of 1:1, which determine the fusibility and the viscosity of the flux, with 10% zinc chloride (ZnC12) to lower the flux melting point.
The activating additions used were the sodium boro-fluoride (~aBF4) and cesium fluoride (CSF)o The effect of these additions upon the angle of wetting ~ of the foundry paste is illustrated by two diagrams (Figs. 4 and 5) where the foundry paste angle of wetting ~
values are plotted on the Y-axis, the X-axis values representing the contents in the f~ux of sodium borofluoride (NasF4) (Fig. 4) and of cesium fluoride (CsF) (Fig. 5).
- Curves A (Fig. 4~ and B (Fig. 5) show that -the optimum percentage of the additions (shaded areas), which improve the '~' ' corundum containing foundry paste wettability, lies in the range from 5 to 8% for sodium borofluoride (NaBF4) and 8 to 10% for cesium fluoride (CsF).
A high content of additions either lowers sharply the quality of the hardened surface layer of castings due to a considerable evolution of boron fluoride (BF3) resulting from the decomposition of sodium borofluoride (NaBF~) or is ineffec-tive as is readily apparent from Fig. 5 for cesium fluoride (CsF).
The combined action of additions of sodium boro~
fluoride (~aBF4) and cesium fluoride ~CsF) represented by curve E in Fig. 6 ensures an efficient spreading (angle ~ ) with the time (ts) of a drop of molten cast iron over the surface of the corundum containing foundry paste, this being due to the slagg-ing (closure of surface) of the surface of corundum inclusions by a flux.
The effect of a foundry paste without a flux and that of a foundry paste without activating additions are shown, for comparing the wettability, by the respective curves C and D in Fig. 6.
.
of corund~ has no effect upon the increase in the resistance of the hardened surface layer to erosion by molten alloys, whereas 70% makes the formation of the layer difficult.
Studies of various compositions of flux for process-ing corundum containing foundry pastes covered ones based on a mixture of sodium chloride (NaCl) and potassium chloride (KCl) in a mass ratio of 1:1, which determine the fusibility and the viscosity of the flux, with 10% zinc chloride (ZnC12) to lower the flux melting point.
The activating additions used were the sodium boro-fluoride (~aBF4) and cesium fluoride (CSF)o The effect of these additions upon the angle of wetting ~ of the foundry paste is illustrated by two diagrams (Figs. 4 and 5) where the foundry paste angle of wetting ~
values are plotted on the Y-axis, the X-axis values representing the contents in the f~ux of sodium borofluoride (NasF4) (Fig. 4) and of cesium fluoride (CsF) (Fig. 5).
- Curves A (Fig. 4~ and B (Fig. 5) show that -the optimum percentage of the additions (shaded areas), which improve the '~' ' corundum containing foundry paste wettability, lies in the range from 5 to 8% for sodium borofluoride (NaBF4) and 8 to 10% for cesium fluoride (CsF).
A high content of additions either lowers sharply the quality of the hardened surface layer of castings due to a considerable evolution of boron fluoride (BF3) resulting from the decomposition of sodium borofluoride (NaBF~) or is ineffec-tive as is readily apparent from Fig. 5 for cesium fluoride (CsF).
The combined action of additions of sodium boro~
fluoride (~aBF4) and cesium fluoride ~CsF) represented by curve E in Fig. 6 ensures an efficient spreading (angle ~ ) with the time (ts) of a drop of molten cast iron over the surface of the corundum containing foundry paste, this being due to the slagg-ing (closure of surface) of the surface of corundum inclusions by a flux.
The effect of a foundry paste without a flux and that of a foundry paste without activating additions are shown, for comparing the wettability, by the respective curves C and D in Fig. 6.
.
Claims (15)
1. A metal casting having a hardened surface layer formed of a casting metal and alloying elements, wherein the hardened surface layer contains grains of a refractory material uniformly distributed throughout its thickness forming inclu-sions of said refractory material in said hardened surface layer, the alloying elements being such as to impart to the casting metal alloy adequate toughness to retain said inclu-sions therein, said casting metal and alloying elements extend-ing between the spaces defined between the grains forming the inclusions of the refractory material, thereby retaining said inclusions in the surface layer.
2. A metal casting as claimed in claim 1, wherein the casting metal is iron, the alloying element is nickel and the refractory material is corundum.
3. A metal casting as claimed in claim 2, wherein the corundum grains have a diameter of 0.2 to 3.0 mm.
4. A metal casting as claimed in claim 3, wherein the corundum grains have a diameter of 0.1 to 2.0 mm.
5. A metal casting as claimed in claims 2, 3 or 4, wherein the corundum grains occupy more than 50% of the volume of the surface layer.
6. A metal casting as claimed in claims 2, 3 or 4, wherein the concentration of nickel in the hardened surface layer decreases gradually in depth.
7. A metal casting as claimed in claims 1, 2 or 3, wherein the hardened surface layer has a thickness of up to 15 mm.
8. A method for manufacturing metal castings as defined in claim 1, which comprises preparing a foundry paste by mixing together powder alloying elements with a binder and admixing thereto a powder refractory material in combination with a flux; applying a layer of said foundry paste upon the surface of a foundry mould; drying said layer; contacting said layer with a liquor of said flux; drying the thus formed layer, and filling the foundry mould with overheated molten casting metal such that the molten metal penetrates into the foundry paste layer to retain the grains of refractory material forming the inclusions in the formed hardened surface layer.
9. A method as claimed in claim 8, wherein the alloying element in the foundry paste is nickel, the refractory material is corundum, the binder is soluble glass and the casting metal is iron.
10. A method as claimed in claim 9, wherein the foundry paste components are in the following proportions (% by weight):
.
.
11. A method as claimed in claims 9 or 10, wherein the flux is a mixture of metal salts in the following proportions (% by weight):
.
.
12. A method as claimed in claim 9, wherein the foundry paste components are in the following proportions (% by weight):
.
.
13. A method as claimed in claims 9 or 12, wherein the flux is a mixture of metal salts in the following proportions (% by weight):
.
.
14. A method as claimed in claims 9, 10 or 12, wherein the corundum grains have a diameter of 0.2 to 3.0 mm.
15. A method as claimed in claims 9, 10 or 12, wherein the corundum grains have a diameter of 0.1 to 2.0 mm.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SU2469151 | 1977-04-21 | ||
| SU772469151A SU753526A1 (en) | 1977-04-21 | 1977-04-21 | Ingot mould |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1111673A true CA1111673A (en) | 1981-11-03 |
Family
ID=20702135
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA301,552A Expired CA1111673A (en) | 1977-04-21 | 1978-04-20 | Metal casting with hardened surface layer and method for the manufacture thereof |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS53146928A (en) |
| CA (1) | CA1111673A (en) |
| DE (1) | DE2817592C2 (en) |
| FR (1) | FR2387712A1 (en) |
| SU (1) | SU753526A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5278005A (en) * | 1992-04-06 | 1994-01-11 | Advanced Energy Technologies Inc. | Electrochemical cell comprising dispersion alloy anode |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102013200680B4 (en) * | 2012-01-19 | 2017-08-03 | Ksb Aktiengesellschaft | Method for producing a component provided with a wear protection layer and a device for carrying out the method |
| CN102554147B (en) * | 2012-03-07 | 2013-11-13 | 四川川投峨眉铁合金（集团）有限责任公司 | Combined type ingot mould and casting method thereof |
| CN103016723B (en) | 2012-11-29 | 2016-08-03 | 广东肇庆动力金属股份有限公司 | A kind of aluminum contains the preparation method of cylinder jacket |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1893539A (en) * | 1930-12-11 | 1933-01-10 | American Abrasive Metals Compa | Method of casting abrasive-faced articles |
| US1893540A (en) * | 1931-01-26 | 1933-01-10 | American Abrasive Metals Compa | Method of casting abrasive-faced articles |
| DE710259C (en) * | 1936-03-06 | 1941-09-09 | Nikolaus Graf V Ballestrem Dr | Process for producing the wear-resistant inner surface of metal pipelines for flushing or blowing in mining |
| US3450189A (en) * | 1966-08-22 | 1969-06-17 | Int Nickel Co | Process of coating metal castings |
| FR2002321A1 (en) * | 1968-02-21 | 1969-10-17 | Inst Odlewnictwa | |
| DE1949777A1 (en) * | 1968-11-13 | 1970-10-01 | Zentralinstitut Schweiss | Highly wear-resistant castings prodn |
| DE2006095C3 (en) * | 1970-02-11 | 1979-05-10 | Motoren- Und Turbinen-Union Muenchen Gmbh, 8000 Muenchen | Use of a lacquer-like paint |
| JPS52730B2 (en) * | 1973-02-12 | 1977-01-10 | ||
| JPS5026721A (en) * | 1973-07-11 | 1975-03-19 |
-
1977
- 1977-04-21 SU SU772469151A patent/SU753526A1/en active
-
1978
- 1978-04-20 CA CA301,552A patent/CA1111673A/en not_active Expired
- 1978-04-20 FR FR7811713A patent/FR2387712A1/en active Granted
- 1978-04-21 JP JP4675378A patent/JPS53146928A/en active Pending
- 1978-04-21 DE DE19782817592 patent/DE2817592C2/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5278005A (en) * | 1992-04-06 | 1994-01-11 | Advanced Energy Technologies Inc. | Electrochemical cell comprising dispersion alloy anode |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2387712A1 (en) | 1978-11-17 |
| JPS53146928A (en) | 1978-12-21 |
| DE2817592A1 (en) | 1978-10-26 |
| SU753526A1 (en) | 1980-08-07 |
| DE2817592C2 (en) | 1983-11-17 |
| FR2387712B1 (en) | 1980-08-29 |
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