US2100537A

US2100537A - Ferrous metal

Info

Publication number: US2100537A
Application number: US37811A
Authority: US
Inventors: Martin J Conway
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-08-26
Filing date: 1935-08-26
Publication date: 1937-11-30
Anticipated expiration: 1954-11-30

Description

Nov. 30, 1937. M. J. CONWAY FERROUS METAL Filed Aug. 26, 1935 I INVENTOR:

WITNESJEJ ATTORNEY-3'.

Patented Nov. 30, 1937 UNITED STATES PATENT OFFICE.

muons METAL Martin J. Conway, Coatesville, Pa. Application Augus't 26, 1935, Serial No. 37,811

13 Claims.

or their mixtures, products resembling wrought iron in structure but of superior corrosion resistance as contrasted with ordinary wrought iron.

Still another object is to utilize iron and steel scrap to provide articles somewhat similar structurally to wrought iron but having enhanced corrosion resistance as contrasted with ordinary Wrought iron.

A further object is to convert bundled scrap steel or iron, either or both, by direct operations, and without remelting, into useful articles having superior corrosion resistance as contrasted with the original bundled material.

Another object is to apply wrought iron fagoting practice to the production of articles of steel or iron, or their mixtures,' characterized by possessing mechanical properties adequate to their intended purpose and having substantial corrosion resistance. I

The invention maybe described in connection with the accompanying drawing in which Fig. 1 is a schematic perspective view showing a bundle of steel scrap for use in the practice of the inven tion; Fig. 2 a perspective view illustrating schematically the macrostructure of a steel bar produced by the practice of the invention from the bundle shown in Fig. 1; Fig. 3 a perspective view of a fagot or pile made in accordance with the invention from bar steel; and Fig.4 a schematic perspective view showing the application of the invention to powdered iron.

The invention is applicable to steel, either of the plain carbon *variety or of the alloy type, such as, for example, steels containing, singly or in combination, chromium, tungsten, manganese, silicon, nickel, cobalt, copper, vanadium, molybdenum, titanium, and other alloying elements. It is applicable likewise to the treatment of iron, whether plain or alloyed, and also to.the treatment of mixtures of steel and iron or wrought iron. Since the invention is directly applicable to all these materials it will be understood that for brevity of reference in generalized discussion of the invention reference may be made to the individual materials but that such reference equally contemplates the other materials referred to.

This invention applies to the making of metallic articles by hot working masses composed of individual pieces of the solid metals referred t6, 5 i. e., without remelting them. In accordance with the invention the pieces of metal, whether iron or steel, or mixtures thereof, are treated before hot working to provide the surfaces with a coating comprising an oxide adapted to increase the corrosion resistance of the finished article as contrasted with an article made similarly without the use of such an oxide. The oxide is selected and used in an amount such as to provide the desired corrosion resistance. The thus coat- 1 ed material in the form of compact masses, e g., compressed bundled scrap, is then hot worked, as by rolling, pressing, forging, or similar operations, to cause consolidation, or welding, of the individual pieces with formation of an integral product in which the oxide remains preponderantly as such distributed throughout its structure. In other words, the solid metal pieces are caused to coalesce by hot working, the oxide applied prior to working to the metal surfaces being retained in and-disseminated through the structure of the finished article.

In this manner there are produced articles having superior corrosion resistance as contrasted with articles either made in the same way but without the use of such oxide, or made by processes in which such oxide is wholly or for the most part reduced withformation of an alloy of the ferrous base and the metal liberated from the oxide. The article thus produced may then be subjected to any necessary fabricating operations, the-practice of the invention not substantially interfering with customary practice in such operations.- I

Various oxides adapted to reduce corrosion of 'iron and steel may be used in the practice of the invention. Chromium oxide is the preferred example. There mayalso be used other oxides adapted to confer improved corrosion-resisting properties when used in the manner described herein, examples beingnickel oxide, titanium oxide, vanadium oxide, and cobalt oxide. If desired there may be used mixtures of these oxides.

Insome instances the properties of-the resultant article may be varied by using-a mixture of one or more such oxides and another substance,- slags, slag-forming oxides, silica, and slag-far n ing compositions being examples of the latter materials. Thus, silica may be mixed with the corrosion-repressing oxide, or there may be used iron silicate slags, or substances productive thereof under operating conditions, and other slag and slag-like materials. As to slag materials I prefer those which form slags of glass-like nature. v

A major embodiment of the invention contemplates its application to scrap metal,.particularly sheet scrap. In this aspect of the invention the metal is compressed into bundles,"such as those in which scrap-metal is commonly marketed, to prepare it for hot working. The oxide may be applied to the surfaces of the metal according to a variety of procedures which will suggest themselves. Chief among these are immersion of the metal in an aqueous or other suspension of the oxide, or spraying the metal with a suitable oxide suspension in a liquid medium, or with the dry powdered oxide. The chief criterion is that the oxide shall be uniformly distributed throughout the bundle and over the surfaces of the solid metal. If desirable there may be added to the "coating material a temporary binder to maintain adherence to the oxide upon the surfaces until subsequent hot working hasconsolidated the material.

The metal may be coated either before or after it has been bundled. Where the bundle has not been compacted suiliciently to prevent entry and distribution of the coating material it is preferred to coat the metal in bundled form because the bundling of previously coated metal may tend to cause the oxide coating to become dislodged to a greater or lesser extent. Thecoated bundle is then compressed to densify it as far as possible,

to minimize oxdiation during subsequent heating and to simplify hot working. It is then heated and welded by application of pressure,'e. g. by rolling, forging, or simple pressing. This pro- 'duces an integral welded structure in which the coating material cooperates to produce a'structure resembling that of wrought iron. The article may be brought to finished form by such an operation, or there may be produced billets and the like for subsequent fabricating operations.

A particular feature of the present invention resides in the utilization of tinned steel scrap, of which large quantities are available. practice of the invention the scrap is detinned according to any suitable procedure, and the detinned steel scrap is then compressed to produce bundles of conventional form, illustrated schematically in Fig. 1. The bundle is then treated as described above to provide it with, for instance, a coating of chromic oxide and silica distributed as uniformly as possible over the surfaces of the entire bundle and in an amount adapted to provide the desired corrosion resistance in the ultimate article. The bundle is then compressed, as in an hydraulic press, and the compressed mass is heated to a welding temperature and hot worked to effect welding and produce a solid integrally united article or billethaving the oxide distributed throughout its structure and preponderantly remaining in its oxide form.

I Fig. 2 represents schematically the macrostructure of a bar rolled from the bundle shown in Fig. 1 and treated as just described. The structure comprises steel grains I between which there are distributed stringers or lamella 2 of the oxide applied to the starting material. Where slag has been added, or slag-like or slag-forming constituents, stringers 2 will, of course, consist of slag. It will be observed that this structure is similar to that which characterizes' wrought iron. "The-product, however,

enhanced corro- In thesion resistance as contrasted with an article made from the same material and in the same manner but without the use of oxide which characterizes the present invention.

The invention is applicable also to the production of articles'characterized by improved corrosion resistance from bar and the like stock, instead of bundled scrap, in the manner applied in wrought iron fagoting practice. This aspect of the invention is illustrated in Fig. 3 which shows a fagot or pile formed from a. plurality of steel bars 3. The contiguous surfaces of the bars are provided with a coating 4 of oxide of the class referred to hereinabove. The resulting pile or fagot is heated to welding temperature and rolled in accordance with customary practice to cause the bars to weld together in'to'an integral mass the structure of which will resemble thatshown inFig. 2.

Similarly, steel sheet scrap, such as detinned scrap, may be bundled, compressed, heated to welding temperature to produce bars which are then assembled into piles and rolled as just described.

The invention is applicable, furthermore, to the production of articles by pressing iron powder, a variety of procedures of this general type being known to the art. This embodiment is illustrated schematically in Fig. 4 which shows a billet formed by compression of iron powder. In the practice of the present invention as applied to such a procedure the particles of iron prior to compression to form the billet are provided with a coating of the oxide of the class contemplated by the present invention. The billet having been formed it is then treated under heat and pressure in accordance with the particular procedure being followed, the result being again an article having the oxide, slag formed from it, or a mixture of the oxide and slag distributed throughout its structure as described hereinabove.

The properties of the article made in accordance with the invention may, of course, be varied by a suitable selection of the starting material.

Thus, certain properties are to be obtained by the use of straight steel material, such as low carbon detinned steel scrap, while other properties may be obtained through the use of alloy steel, or by mixtures of plain carbon and alloy steel. Other mechanical properties may be had by the use of iron, and stfll further variations are obtainable through the use of combinations of throughout the metal structure. Hence reference herein and in the appended claims to retention of the oxide in the finished artlcle' means that I for the most part it is not reduced to free its metallic'constituent. It will be understood, however, from what has been said hereinabove, that since the oxide may unite with other oxides or slag-forming materials to form complex oxides or slags, this is within the contemplation of the invention because such combinations without reduction of the oxide to liberate the metallic constituent cause retention of the oxide within the contemplation of the invention.

The criterion as to the amount of oxide incorporated in the metal is that enough is used to produce the desired degree of corrosion resistance. Clearly the exact amounts will depend upon the composition of the metal used, upon the oxide used, upon the condition in which the article is used, upon the character of corroding media encountered, and perhaps upon other factors, so that exact values for the oxides suited to all conditions can not be given. However, for many purposes it is preferred to use chromium oxide or cobalt oxide in an amount equivalent to from 0.1 to 2 per cent of chromium or nickel, as the case may be, in the finished article; vanadium and titanium oxides in amounts corresponding to about 0.15 to 3 per cent of vanadium or titanium in the finished article; and nickel oxide equivalent to about 0.2 to 4 per cent of nickel in the finished article. 1

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. That method of making ferrous metal articles which includes preparing a bundle of steel scrap, applying to the surfaces of the scrap a coating comprising (1) an oxide adapted to confer corrosion resistance on the finished article, and (2) material of the group silica, silicate slag, and materials productive of silicate slag, and hot working the bundle heated to a welding temperature and thereby consolidating it into an integrally welded and mechanically strong article .having said oxide preponderantly retained therein and distributed therethrough and im parting corrosion resistance to the article, the

artlclehaving a wrought iron-like structure.

2. That method of making ferrous metal articles which comprises applying to the surfaces of steel barsva coating comprising an oxide adapted to confer corrosion resistance on the finished article, forming a pile from the coated bars, heating the pile to a welding temperature, and hot working the heated pile to cause welding and form an article having said oxide preponderantly retained therein and uniformly distributed therethrough in an amount imparting corrosion resistance to the article, the article having a wrought iron-like structure.

a 3. That method of making ferrous metal articles which comprises applying to the surfaces of steel bars a coating comprising a corrosion-repressing oxide of the group chromium, nickel,

vanadium, titanium, cobalt, forming a pile from the coated bars, and hot working the pile heated to a welding temperature to cause welding and form an article having said. oxide preponderantly retained therein and uniformly distributed therethrough and imparting corrosion resistance to the article, said oxide being present in an amount equivalent to about 0.1 to 4 per cent N of the metal of such oxide. the article having a wrought iron-like structure.

4. That'method of making ferrous-metal articles which includes the steps of applying to the surfaces of solid steel, iron, or steel and iron material, a coating comprising an oxide adapted to confer corrosion resistance on the finished article, and hot working at a welding temperature a mass composed of a plurality of pieces of such coated material and integrally welding said pieces into a consolidated, unitary and mechanically strong article having said oxide retained therein as a wrought iron-like structure and in an amount imparting corrosion resistance to the article.

5. That method of making ferrous metal articles which includes the steps of applying to the surfaces of solid steel, iron, or steel andiron material, a coating comprising a corrosion-repressing oxide of the group chromium, nickel, vanadium, titanium, cobalt, and hot working at a welding temperature a mass composed of a pinrality of pieces of such coated material and integrally welding said pieces into a consolidated,

-unitary and mechanically strong article having said oxide preponderantly retained therein as a wrought iron-like structure, said oxide being present in the finished article in an amount equivalent to about 0.1 to 4 per cent of the metal of such oxide. v

6. That method of making ferrous metal articles which includes the steps of applying to the surfaces of solid steel, iron, or steel and iron material, a coating comprising silica and a corro-- sion-represslng oxide of the group chromium, nickel, vanadium, titanium, cobalt, and hot working at a welding temperature amass composed .of a plurality of pieces of such coated material cobalt, and applying pressure to a mass composed of a plurality of pieces of such coated material, the mass being heated to a welding temperature, and thereby integrally welding said pieces into a consolidated, unitary and mechanically strong article having said oxide preponderantlyretalned therein as a wrought iron-like structure and in an amount imparting corrosion resistance to the article.

8. That method of making ferrous metal articles which includes the steps of' applying to the surfaces of iron powder a coating comprising an oxide adapted to confercorrosion resistance on the finished article, compressing the coated powder to form a billet, and hot working the billet heated to a welding temperature and the billet at a welding temperature and thereby consolidating it into an integrally welded and mechanically strong article having said oxide preponderantly retained therein and uniformly distributed therethrough and imparting corrosion resistance to the article, said oxide being present in an amount equivalent to about 0.1 to 4 per cent of the metal of such oxide, the article having a wrought iron-like structure.

10. That method of making ferrous metal articles which comprises preparing a bundle of steel scrap, applying to the surfaces of the scrap in the bundle a coating comprising an oxide adapted to confer corrosion resistance on the finished article, heating the bundle to a welding temperature, and hot working the thus heated and coated bundle and thereby consolidating it into an integrally welded and mechanically strong article having said oxide preponderantly retained therein and uniformly distributed therethrough and imparting corrosion resistance to the. article, said oxide being present in an amount equivalent to about 0.1 to 4 per cent of the metal of such oxide, the article having a wrought iron-like structure.

11. That method of making ferrous metal articles which includes preparing 'a bundle of steel scrap, applying to the suri'aca of the scrap in the bundle a coating comprising (1') a material of the group silica, silicate slag, and substances productive of silicate slag, and (2) a corrosion-repressing oxide of the group chromium, nickel, vanadium, titanium, and cobalt, and hot working the coated bundle heated to a welding temperature and thereby consolidating it into an integrally welded and mechanically strong article having said oxide preponderantly retained therein and uniformly distributed therethrough and imparting corrosion resistance to the article, the articlehaving a wrought iron-like 5 structure. I.

12. That method of making ferrous metal articles which comprises preparing a bundle of alloy steel scrap, applying to the surfaces of the scrap in the bundle a coating comprising a corrosion-repressing oxide of the group chromium, nickel, vanadium, titanium, and cobalt, compressing the bundle under high pressure, and hot working the bundle heated to a welding temperature to weld it into an article having said oxide preponderantly retained therein and uniformly distributed therethrough and imparting corrosion resistance to the article, the article having a wrought iron-like structure.

7 13. That method. of making ferrous metal 20 articles comprising the steps of bundling and compressing steel scrap, hot working said bundle to form a steel bar, coating the surfaces of a plurality of said bars with a corrosion-repressing oxide of the group chromium, nickel, vanadium, titanium and cobalt, forming a pile or fagot from such coated bars, heating the pile to a'welding temperature and hot working it and thereby welding said bars into an integrally welded and mechanically strong article having said oxide preponderantly retained therein and distributed therethrough' and imparting corrosion resistance to the article, the article having a wrought ironlike structure.

MARTIN .1. conwn