US1014425A - Manufacture of steel. - Google Patents

Description

No Drawing.

seiner metal is amount of pi metal to preferably in WILLIIAM- n. WALKER, on NEW roan, N. Y.

,MANUFACTUBE OF STEEL.

foresee;

To all whom it may concern:

Be it known that I, WILLIAM R. WALKER, of the borough of Manhattan, in'the city of New York, county have invented an mprovement in the Mannfacture of Steel, of which the following is a Specification. I

In the practice of my invention, I introduce molten pig metal into a Bessemer converter and blow 'it has been eliminated and the carbon reduced to a definite percentage, preferably to about .05 per cent, which percentage can be gaged with accuracy because it is about the percentage contained in themetal at the time when the flame drops, a phenomenon which is well known and readily recognized by the skilled blower. I then add to the desiliconized and substantially decarburized metal a proportion of carbon suflicient to raise its carbon content to a definite percent. age, preferably to about .3 per cent, though this percentage may be varied. The carbon addition is preferably made by adding to the Bessemer metal in. theladle pig iron either in the form of cold pig or molten pig, and as the percentage of carbon of the Bessubstantially constant, the be added in the ladle can be readi y determined with substantial precision. The carbon'may be introduced by adding anthracite coal or powdered coke to the metal instead of adding carbon in the form'of-pig iron. If pig iron is added, it is the molten condition. metal thus enriched in carbon is then charged into an electrically heated furnace where it is treated preferably with basic additions for removal of sulfur and phosphorus, and for increase of its heat to bring it into the refined and heated condition proper for casting into the ingot molds.

The importance of adding carbon to the blown metal before introducingit into the electric furnace is that in this way the loss by skulling is lessened, and by bringin the -metal to a definite carbon content the cats furnace are made uniform in the product renthe manufacture in the electric character and duration, deredmore uniform and greatly facilitated.

As the decarburized metal is low in carand State of New York,'

the-rein until the silicon.

The

p Specification of Letters Patent.

Application filed June 18, 1909. Serial No. 502,865

f nnissunn tent is rendered easy by centage,

. Patented Jan. 9, 1912.

bon whentaken from the converter and is often transferred a considerable distance to the electric furnace, a considerable amount of this metal will solidify in the ladle and form skulls therein. This skulling action will reduce the amount of metal poured into the electric furnace from the ladle, and as the skulling action will vary, the amount poured in will vary.- By adding carbon to the metal before its being carried to the electric furnace, I raise its carbon content and thus also its melting point, and hence prevent or greatly lessen the amount of skulling during the transfer to the electric furnace. This, therefore, makes the charges more uniform'in amount as poured into the electric furnace.

The-obtaining of a ,uniform carbon conadding carbon to the blown metal rather than by attempting to stop the blow at the desired point, for to determine the point of stopping before the flame drops is very difficult, while to add the necessary-- percentage of carbon to the bath depleted ofcarbon is easy.

I am aware that it is old-to eliminate practically all ofthe carbon and steel before recarburizing and. do, not desire to claim this, but I ing prior to transferring thefimetal to the electric furnace.

The best percentage of carbon to be added will be governed somewhat by the period 50f;

time. during which the metal is 'to be held in the ladle before pouring into theelectric furnace, being greater as the time is longer. I claim:- 1 In the manufacture of steel, the steps consisting of removingthe carbon of pig iron to a subst-antially, definite percentage, then, re'carburizing to a sufficient extent to lessen skulling during transfer, and then transferring the metal to and treating it in an electric? furnace. 1

2. In the manufacture of steel, the steps consisting in-bessemerizing pig iron,,reducingits carbon to a substantially definite perth'en adding carbon to a sufiicient extent to lessen skulling during transfer, and then transferring the metal to and treating it in an electr1c furnace.

3. In the manufacture of steel, the steps do desire to claim the recarburiz-' s'rn'rns PATENT ormon'.

consisting of bessemerizing pig iron to 1 In testimeny whereof, I have hereunto set point where the flame drops, then removing my hand. the metal from the converter, adding carbon thereto to a suflicient extent to lessen skull- 5 ing during-transfer, and transferring .iihe Witnesses:

metal to and treating it in an electric fur- ALFRED T. DUFFIELD, nace. CLARENCE 'D. KERR.

WILLIAM RQWALKER.