US2012599A - Production of wrought iron articles - Google Patents

Description

Aug. 27, 1935. M. J. CONWAY 2,012,599

PRODUCTION OF WROUGHT IRON ARTICLES Filed NOV. 6, 1935 Patented Aug. 27, 1935 PRODUCTION OF WROUGHT IRON ARTICLES Martin J. Conway, Coatesville, Pa.', assignor of one-half to Charles Hart, Media, Pa.

Application November 6, 1933, Serial No. 696,777

' 7 Claims. (Cl. 75-27) This invention relates to articles made from wrought iron, and particularly to wrought iron articles of improved corrosion resistance.

It is a major object of the invention to provide a method for improving the corrosion resistance of wrought iron, which is simple, easily practiced, effectively imparts increased corrosion resistance to wrought iron as produced by the various processes now commercially used, does not materially increase the cost of the articles, and is applicable to the various processes used for making such articles.

The invention may be described in connection with the accompanying drawing, in which Fig. 1 is a schematic perspective view intended to illustrate the macrostructure of a bar formed in the practice of the invention, and Fig. 2 a perspective view showing the application of the invention to the forming of articles from muck-bar.

In accordance with this invention there is incorporated in the wrought iron structure a metallic oxide which wholly or prepcnderantly remains as such in the finished article and which increases the natural resistance to corrosion of the wrought iron which forms the basis of the article. Chromic oxide or titanium oxide, or both, are preferably used in the practice of the invention, for which reason they will be referred to in fur"- ther description of the invention. Other oxides may also be used to increase the corrosion resistance, such as vanadic oxide and oxides equivalent to the three oxides just named, i. e., oxides adapted to confer corrosion-resisting properties to the wrought iron. Also, if desired. more than one such oxide may be used. i

The invention is applicable either to the formation of wrought iron or in the production of articles from previously prepared wrought iron. For example, it may be applied to the paddling and shotting processes, both of which are well known and understood by those skilled in the art. In this aspect of the invention chromic oxide, or titanium oxide or a mixture of the two, is added to the slags produced in the puddling process, or to the synthetic slags used in the shutting processes, such as in the so-called Aston-Beale process. Thus the chromic, or other, oxide enters the slag which becomes disseminated throughout the ball" which results from such processes.

The use of these oxides does not change the usual fabricating. operations, the balls being squeezed and further worked up by the customary operations used in this art, as by making muckbar, forming piles thereof, and hot working the piles to form a welded bar which may then be processed to final shape. In the working of the ball and resultant muck-bar the slag forms inclusions elongated in the direction of rolling,as usual, and these inclusions contain the chromic, or other, oxide which thus appears in the product as lamellar inclusions.

The structure of the product thus is substantially that of ordinary wrought iron, so that all of the desirable qualities of wrought iron are retained. However, the chromic, or other, oxide 10 content of the slag confers increased corrosion resistance. The'structure may be illustrated by Fig. l, which is a perspective sketch intended to show the structure of a bar made in accordance with the invention. It shows the ferrite in the customary equiaxed crystals I, and lamella 2 of slag containing chromic, or other, oxide, these inclusions being similar in form and distribution to those obtained in ordinary wrought iron practice.-

The chromic, or other, oxide may be incorporated in the structure of previously fabricated wrought iron, instead of adding it in making the ball. This aspect of the'invention may be described with relation to the fabrication of muckbar. In this embodiment of the invention muckbaris made according to customary procedure and the faces of the bars which are to be in contact in the pile or fagot are coated with an oxide, e. g. chromic, titanium, or vanadic oxide, or any combination of them, in accordance with this invention. For example, the adjacent faces and edges of muck-bars 3, Fig. 2, are coated with finely divided chromic oxide to provide films 4 thereof interposed between the adjoining faces and edges of the muck-bar. The resulting pile 5 or fagot is then heated to .welding temperature and formed in accordance with customarypractice, as by rolling, to cause the .bars to weld together and form an integral bar.

As applied to muck-bar the result is the production of an article containing lamellar inclusions of chromic oxide similar in shape and positioning to those produced when the oxide is used in p'uddling-or shotting operations, as will be understood from a consideration of what occurs in 5.

rolling the pile shown in Fig. 2. Thus the structure will be similar to that shown in Fig. 1. It

, will be understood that it is more desirable to add these oxides to the slag during the puddling or shotting, and they may be also used with the muck-bar as described hereinabove.

The oxide is used in an amount such as to imof chromic and/orftitanium oxide such that the slag will carry from about 5 to 15 per cent of its weight thereof, while in the case of vanadic oxide about 3 to 7 per cent of the total weight of the slag may consist of this constituent. Inasmuch as the slag content of wrought iron is quite low, it will be seen that the amount of corrosion-resisting oxide needed is also low.

The invention contemplates retention of the chromic or vanadic oxide in the finished article. There may be some reduction of the oxide added to improve corrosion resistance, for example under the influence of silicon or carbon in the iron,

but this is incidental to the main purpose ofthe process, it being contemplated that the major portion of the oxide will remain as such in the slag particles, and even where such reduction occurs it is accidental, not intentional, and usually slight because usually wrought iron is low in such reducing agents.

Reference has been made herein and in the appended claims to retention of the chromic or other oxide in the finished article. This is intended to mean that for the most part it is not reduced to free its metallic constituent. However, the oxide may not appear as free oxide, since it may unite with other oxides in the slag to form complex oxides, but within the contemplation of the invention such union of oxide and slag constituents, without reduction of the oxide to liberate metal, represents retention of the oxide.

Actual experience in of the finished articles are not adversely afiect! ed while the corrosion resistance of the product is materially increased, It will be seen, moreover, that this is accomplished simply and cheaply and without interfering with or requiring any j material alteration of existing wrought iron practice. It has been proposed to increase the corrosion resistance of wrought iron by alloying it with chromium and other metals, as by reduction of their oxides. The present invention, however, is simpler and less expensive, and more eas- 1. In the production of articles of wrought iron,

the step comprising incorporating in the wrought the use of the inventionv has' shown that the mechanical characteristicsiron structure during manufacture of the article and for retention in the slag structure of the finished article at least one metallic oxide of the group comprising chromic oxide, titanium oxide, vanadic oxide and their equivalents adapted to increase the corrosion resistance of the article, said oxide being present in an amount such as to constitute from about 3 to 15 per cent of the slag content of the article, and thereby imparting increased corrosion resistance as compared with a similar article not containing said oxide.

forming a pile or fagot therefrom, heating the pile to welding temperature, and hot forming an article therefrom, said oxide forming lamellar inclusions in the slag structure of the finished article and imparting corrosion-resisting properties thereto.

3. A process according to claim 2, said oxide to the article, said oxide being present in an amount corresponding to about 3 to 15 per cent of the slag.

5. A wrought iron article characterized by having lamellarinclusions of slag containing from about 3 to 15 per cent of at least one oxide of the group comprising chromic oxide, titanium oxide, and vanadic oxide and equivalent oxide adapted to impart corrosion-resisting properties to the article.

6. A wrought iron article characterized by having in its slag inclusions chromic oxide adapted to confercorrosion-resisting properties to the article, said oxide being present in an amount corresponding to about 5. per cent of the slag.

'7; In the production of articles of wrought iron, the step comprising incorporating in the wrought iron structure during manufacture of the article and for retention in the slag structure of the finished article chromic oxide adapted to increase the corrosion resistance of the article, said oxide being present in an amount such as to constitute about 5 per cent of the slag content of the article, and thereby imparting increased corrosion resistance as compared with a similar article not containing said oxide.

' MAR'I'IN J. CONWAY.

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