US1745645A - Albert sattvettr - Google Patents

Description

Patented Feb. 4, 1930 UNITED STATES PATENT OFFICE ALBERT SAUVEUR, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO THE AMERICAN ROLLING MILL COMPANY, OF MIDDLETOWN, OHIO, A CORPORATION OF OHIO IRON-CARBON ALLOY No Drawing.

My invention relates to alloys of carbon on a base of commercially pure iron, which so far as I am advised is a hitherto unknown field in steel production.

It is my object to provide a steel which is less brittle, tougher and more resistant to shock and fatigue, than the best steels of the past, and one in which the tendency to crack during quenching is reduced to a minimum. It is my object to provide a steel which will more readily absorb carbon in case hardening than the best crucible steel. Also it is my object to provide a steel which has practically none of the defects attributed to the presence of a small percentage of phosphorus.

I accomplish my objects by the provision of a steel which contains carbon in desired percentages, but practically no manganese, silicon or phosphorus, and low sulphur.

To accomplish my objects it is believed by me to be necessary to first drive off by a rigorous refinement, say in any suitable furnace such as the open hearth, electric furnace, etc., all impurities present in a ferrous bath, including the carbon and manganese, a process of refinement such as I may employ is described in U. S. Patent to R. B. Carnahan #987,549, Mar. 21, 1911. Following this, it will be found best to degasify the heat, and then to add the carbon, either under protection of a slag and (or) under reducing conditions.

I do not. desire to be limited as to process, however, although I cannot at the'present writing conceive of any better method of attaining my product, which forms the basis of this specification, unless the carbon is first driven off together with the other usual metalloids, including manganese, and is then added under conditions which will prevent the oxidation of the carbon.

As an example of my invention, I produce alloys containing carbon in desired percentages, say for one example carbon 1%. The remainder of the alloy will contain iron, with or without other alloying elements, and manganese not over 035%, silicon not over 035%, phosphorus not over .01%, and sulphur not over .03%.

It will be entirely practical to produce an Application filed June 4, 1925. Serial No. 35,012.

alloy in which the manganese is as low as .02% and the silicon as low as .01% or less.

It will be'noted that I refer to commercial steels in my remarks herein and not to laboratory production in which like steels in very small quantities may have been produced at great expense in the past.

Commercially it has not been possible to provide carbon steels much lower than 20% in manganese, and steel makers have not considered it possible to work a carbon steel in which the manganese was any less than 20% with the very low silicon, phosphorus and sulphur. However, the manganese is not necessary and except in special steels is a detriment. Silicon is a retarder of carbon absorption in the case hardening process, and phosphorus causes steels to be brittle while sulphur produces red shortness requiring manganese as a protection. My new steel will take a more drastic quenching without cracking, for like carbon content, than steels formerly known. Compared to other steels containing equal amounts of carbon, my new steel will be softer and more ductile. It will possess greater resistance to shock, to fatigue and to corrosion. It will also be freer from segregation and from inclusions and will have more uniform mechanical properties when tested in longitudinal, transverse or other directions. It will have greater electrical conductivity and greater weldability. Case hardened articles made of my steel will have, for liketreatments, tougher cases and tougher cores.

Having thus described my invention, what i of manganese adding carbon thereto prior to permitting the material to solidify.

3. As a new article of manufacture a com-- mercial steel similar in amounts of silicon, sulphur and phosphorus to manganese-bearing steels, and having a similar carbon content for the same desired roperties resulting therefrom, but differing rom the said steels in containing practically no manganese, the

' manganese being 035% or less and the carbon over 05%.

4. A steel which differs from commercial manganese bearing carbon steels in containing practically no manganese, but is alike to them in having a carbon content for the desired properties similar to that which is to be found in said steels for such properties, said steel being practically free of silicon and phosphorus also.

5. A steel which diflers from commercial manganese-bearing carbon steels in containing practically no manganese, but is alike to them in having a carbon content for the desired properties similar to that which is to be found in said steels for such properties, said steel having not over 035% of manganese, of sulphur and of silicon and having not over .01% of phosphorus.

6. A quenching and case hardening steel of commercially pure iron alloyed with carbon as the essential ingredient, in an amount suitable for the desired properties, and containing not over 035% manganese and. not over 035% silicon, and not over .01% phosphorus, and not more than substantially .03% sulphur.

7. A quenching and case hardening steel consisting of commercially pure iron with carbon as the essential alloying element in percents greater than .05%, and in an amount suitable for the desired properties.

ALBERT SAUVEUR.