US536083A - And joseph k - Google Patents

Description

' UNITED STATES PATENT FFIGE.

SAMUEL HUFTY, OF CAMDEN, NEW JERSEY, AND JOSEPH K. CALDWELL, OF PHILADELPHIA, PENNSYLVANIA.

PROCESS OF CONVERTING CAST-IRON INTO STEEL.

SPECIFICATION forming part of Letters Patent No. 536,083, dated March 19, 1895.

Application filed une 2, 1893. Renewed November 8, 1894- Serial No. 528,261. (No specimens.)

To aZZ whom it may concern.-

Be it known that we, SAMUEL I-IUFTY, of Camden,New Jersey, and JOSEPH K. CALD- WELL, of Philadelphia, Pennsylvania, both citizens of the United States, have invented certain Improvements in Converting Cast- Iron into Steel, of which, the following is a specification.

The object of our invention is to remove a certain portion of the carbon from cast iron or iron containing carbon in such proportion that itis hard and brittle, whereby We are enabled to convert such iron into steel ofsuch ductility that it can be shaped, hammered, drawn, or rolled in the same manner as steel produced in the ordinary way or can be tempered in order to form cutting tools or for other purposes for which temperingis usually resorted to.

The mainfeature of our invention consists in subjectingthe cast iron While highlyheated, but still considerably below the point of fusion, to the action of the gases resulting from the decomposition by heat of nitro-muriatic acid. This acid (the aqua-regia of commerce) is a very powerful oxidizingagent, differingin its action from either nitric acid or muriatic acid, and we have found that the gases resulting from its decomposition under heat, have the efiect of attacking and removing carbon in the form in which the same is found in cast- The nitro-muriatic acid can be decomposed directly in the furnace or crucible containing the metal, or the gases resulting from the decomposition of the acid can be introduced into such furnace or crucible, if the decomposition is efiected in a separate vessel. 7 i

In carrying out our invention the quantity of acid to be used and the time during which the treatment is continued will, of course, vary, depending upon the bulk of the iron under treatment and the extent of conversion required, increased bulk of material requiring an increased quantity of acid and the extent of conversion being greater or less, depending upon the length of time duringwhich the iron is subjected to the action of the gases. As an instance, however, of what maybe done in the practical carrying out of our invention we may say that in the treatment of ordinary. white iron the use of thirty ounces of the acid to every one hundred pounds of the iron will give good results. i

We are aware that it is old to treat molten iron with a mixture of hydrochloric and muriatic acids, but such treatment could not accomplish the result obtained by us since a failure to secure the proper grade or softness of steel in castings made from the mass of molten iron can not be remedied; whereas, by treating the cast iron in, solid forms with nitro-muriatic acid, we are enabled to retreat the same castings at any time when the proper or desired softness is not obtained in the first treatment; and furthermore, our castings are not subjected to the action of subsequent fusion.

Having thus described our invention, we claim and desire to secure by Letters Patent The herein described process of decarbonizing cast iron, consisting in subjecting the solid metal to the action of high heat and the gases resulting from the decomposition of nitro-muriatic acid, substantially as described. In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

SAMUEL HUFTY. JOSEPH K. CALDWELL.

WVitnesses:

FRANK E. BECHTOLD, JOSEPH H. KLEIN.