US1987598A - Manufacture of wrought iron - Google Patents

Description

Patented 15, 1935 MANUFACTURE OF wnoUGIrr moN James Aston, Pittsburgh, and Edward 3; Story, Dormont, -Pa., assignorsto A. M. Byers Com pany, Pittsburgh, Pa.,

. sylvania a corporation of Penn-- No Drawing Application,January2411934,

Serial No. 703,140 J 7 Claims. (01. 75417 This invention relates to the manufacture of wrought iron, and more particularly to the manufacture of wrought iron by the Aston process. It relates still more particularly to certain im- 5 proved methods of manufacturing Aston process wrought iron, and especially balls weighing in the neighborhood of three thousand pounds and upwards. The invention has to do primarily with the relationship between the amount of ferrous material and the amount of molten slag admixed in the formation of larger sized balls of wrought iron by the Aston process.

This application is in part a continuation of our copending application Serial No. 626,988, filed July 30, 1932.

The Aston process of manufacturing wrought iron is now well known and comprises admixing ferrous material and molten slag, preferably by pouring molten ferrous material into a slag bath in a receptacle, so that the solidified or partly solidified granules of ferrous material formed during the admixture are individually coated with slag and welded together to form at the bottom of the receptacle a compressible mass or ball of wrought iron. The ball thus formed can be compressed to form a bloom which may then be rolled or reduced to a billet or any other desired form.

In the early experimental work on the Aston process relatively small balls were formed. These balls ranged up to 2400 or 2500 pounds in weight or slightly over, but were very much smaller than the balls ordinarily produced in present day commercial operations. In the manufacture of the smaller experimental balls it was found that good results could be obtained with slag to ferrous material volume ratios of in the neighborhood of 5, 6 or 8 to 1, that is to say, that up to about 8 volumes of slag would be used for admixture with one volume of ferrous material.

Although it might seem logical that the same slag to ferrous material volume ratios as were suitable for the formation of the smaller balls would also be suitable for the formation of larger balls, we have found that, particularly in the formation of balls weighing in the neighborhood of three to four thousand pounds and upwards, this is no longer true. Results obtained in attempting to produce balls of this size using a slag to ferrous material volume ratio of about 8 to 1 or less are distinctly unsatisfactory. The ferrous material is improperly disintegrated or shotted, there being metal in the region of the center of the ball in a somewhat incipient state of fusion. When such a ball is compressed it may behave badly; the surface may bulge due to :the tendency. of the half fused ferrous material at the center to exude toward the surface. When the partly pressed ball is turned in the press for compression in another direction the bulge may again appear. 5 Rolling in a blooming mill of a bloom thus formed may be extremely diflioult, for again a pronounced bulging effect may be felt where the partially fused ferrous material passes through the rolls. In a later pass the bulging, tending to manifest itself 10 in another direction, may throw a fin or fold into the metal. Aside from the operating difficulties, the partly fused ferrous material results in wrought iron of inferior quality, being non-uniform and having undesirable properties such as low tensile strength and ductility.

We have found that in the manufacture of balls weighing in the neighborhood of three or four thousand pounds and upwards a slag to ferrous material volume ratio greater than 8 to 1 should be maintained in order to avoid the disadvantages above mentioned. This is contrary to the early experimental experience with balls ranging up to in the neighborhood of 2500 pounds, and the importance of a relatively high ratio is especially pronounced in making balls over about four thousand pounds in weight. The broad range of slag to ferrous material ratios which we deem suitable for the larger sized balls is from 8 to 1 as a low limit to 25 to 1 as a high limit, and the preferred operating range, particularly in the formation of the usual commercial balls of from about three or four thousand to about ten thousand pounds, is from in the neighborhood of 12 to 1 to in the neighborhood of 20 to 1. In some cases a higher ratio than absolutely necessary is utilized so that there may be a factor of safety insuring complete disintegration of the ferrous material. However, a ratio of greater than 8 to 1 in practically all cases and at least 9 to 1 or slightly greater in most cases is found necessary in making the larger sized balls and does not include any substantial factor of safety.

While we have described certain present preferred embodiments of the invention, it is to be distinctly understood that the same is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims.

We claim:

1. In the manufacture of wrought iron by the Aston process, the step, in the formation of wrought iron balls weighing in the neighborhood of three thousand pounds and upwards, comprisingwfdmix'ifi' g' ferrous material with more than eight times its volume of molten slag.

2. In the manufacture of wrought iron by the Aston process, the step, in the formation of wrought iron balls weighing in the neighborhood of three thousand pounds and upwards, comprising, admixing ferrous material withbetween eight andtwenty -five' tiines its volume of molten slag.

3. In the manufacture of wrought iron by the Aston process, the step, in H the formation of wrought iron balls weighing in tlie rie'ig'hborhood of three thousand pounds and'upwardacomprising admixing ferrous material-wi thatleast about twelve times its volume of; molten slag:

4. In the manufacture of wrought iron by the Aston process, the step, in the formation of wrought iron balls weighing iiithe neigliborll'ood of three thousand pounds and upwards, comprising admixing ferrous material with"between.

about twelve and about twenty times its volume rous material having a volume less than oneeighth the 'volume' of the slag.

7 A-method-ofmaking by the Aston process wrought ironballs: Weighing in the neighborhood of foun thousa'ndmounds and upwards, comprising introducing -into a bath of molten slag ferrous materialhaving a volume not over about ione=t1we1ftli the volume of the slag.

JAlWES ASTON. EDWARD B. STORY.