US1144256A - Method of producing practically pure iron. - Google Patents

Description

critics.

ARTHUR P. scoTT, or BRACKENRIDGE, PENNSYLVANIA, ASSIGNOR To ALLEGHENY STEEL COMPANY, OF PITTSBURGH, EENNSYLVANLA, A CORPORATION OF PENDL METHOD OF PRODUCING PRACTICALLY PURE IRON.

SYLVANIA.

1 $44,256. Specification of Letters Patent.

No Drawing.

To all whom it may concern:

Be it known that I, ARTHUR P. Soon, a subject of the King of Great Britain, residing at Brackenridge, in the county of Allegheny and State of Pennsylvania, have 1nvented new and useful Improvements in Methods of Producing Practically lure Iron, of which the following is a spec1fication.

This invention relates to an improved method of producing practically pure iron.

In the manufacture of steel, and in the manufacture of ingot-iron as made by the basic or acid open hearth process, the Bessemer or crucible process, or the electric furnace process, when the metal is tapped from the furnace or vessel into the ladle previous to ouring or casting into ingots, substantial y all the slag accompanies it. Beinglighter than the metal this slag for the most part floats on the surface of the metal but small quantities of the slag are distributed through the body of the metal in the ladle, as globules or particles, being held by internal friction of the slag against the steel. Ordinarily the molten iron is promptly poured into the molds and these globules or particles of slag pass into the molds with the iron, and become entrapped in the solidifying metal.

The resulting ingot therefore contains occluded in its mass, slag in varying quantities, to the great detriment of the finished material.

The object of the present invention is to so treat the metal bath as to remove these occluded slag particles or globules.

It is well known that the smaller a body is the greater is the proportionate friction surface presented by it, and that when a plurality of very small bodies are combined the friction surface is greatly decreased, and I take advantage of this well known fact in carrying out the improved process. In practising my invention I melt down and refine preferably in an open hearth furnace, or in an electric furnace, or in any combination of the two, a charge of pig iron, cast iron or iron in any other form or combination ordinarily' employed in charging such furnaces in the usual Way. The impurities usually encountered, such as carbon, manganese, phosphorus, silicon and sulfur, are oxidized and eliminated from the bath to the greatest Patented June 22, i915.

Application filed October 6, 1910. Serial No. 585,718.

possible extent by the application of heat,v

fluxes and reagents according to well known practice. When the desired purity is ob tained the metal is tapped or poured from the furnace, or converter, into the ladle, and it is allowed to remain tranquil for a period of four minutes or thereabout before teeming is commenced, during which period the slag floats out. By thus allowing the metal in the ladle to remain tranquil, gathering or coalescing of the slag particles is permitted, whereby the friction surface is reduced and the gathered or coalesced particles will float to the surface. If the teeming is commenced without permitting the metal to stand as described, the occluded slag particles would be held in the metal bath by friction and as a consequence would become entrapped in the solidif ing metal in the molds. If desired the fibating out or elimination of the slag globules or particles, may be expedited during the period the metal is allowed to stand, by agitation of the metal in the ladle, either by rotating the ladle, or otherwise, this step being analogous to the well known gathering or coalescing of the fat globules in butter making.

By the foregoing process I am enabled to produce a practically pure iron which, because of its high degree of purity will solidify'without blow holes or spongy top, and with little or no piping. It is less susceptible to corrosion than any other known iron or steel; is highly malleable and ductile; may be worked at a low heat; and by reason of the fineness of its surface it is particularly receptive to metal coatings of any kind.

I claim as my invention 1. The process of producing practically pure iron which comprises melting down iron in combination with fluxes and reagents to separate the impurities, transferring the purified metal to a ladle and allowing it to remain in the latter for a period of four minutes or thereabout, without heating and without the addition of slag producing reagents, and finally teeming.

2. The process of producing practically pure iron comprising melting down iron in combination with the usual fluxes or reagents, tapping or pouring the metal into a ladle, and allowing it to remain in the ladle agents to purify the same, tapping or pouring the molten metal into a ladle and allow ing the same to remain in the ladle for a period of four minutes or thereabout, and concurrently agitating the molten metal before teeming.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

ARTHUR P. SCOTT.

Witnesses:

CHAS. E. RIORDAN, WM. S. Honors.