US2079058A

US2079058A - Machineable steel and articles formed therefrom

Info

Publication number: US2079058A
Application number: US712138A
Authority: US
Inventors: Louis H Winkler
Original assignee: Bethlehem Steel Corp
Current assignee: Bethlehem Steel Corp
Priority date: 1934-02-20
Filing date: 1934-02-20
Publication date: 1937-05-04
Anticipated expiration: 1954-05-04

Description

able quantity avoids the deleterious Patented May 4, 1937 UNITED STATES PATENT OFFICE MACHINEABLE STEEL AND ARTICLES I FORMED THEREFROM My invention relates tobodies, such as screws,

Louis H. Winkler, Bethlehem Steel Pennsylvania Bethlehem, Pa., assignor to Company, a corporation of No Drawing. Application February 20, 1934,

Serial No. 712,138

6 Claims. (c1. 75-123) which involve as steps ,of their manufacture, up-

setting or cold forming,

tions.

and machining opera- My invention comprisesarticles of manufacture, such as screws, of

rimmed steels containing percentages of sulphur sufiiciently great to render them easily machineable. This invention further comprises such steels themselves.

Relatively high sulphur contents have been used for some time ticularly in screw sto sulphur content have widely used for various purposes.

in machining. steels, parck. Rimmed steels of low been long well known and I have discovered that sulphur in large enough amounts to confer easy machineability, particularly for threading operations,

may be added to rimmed steel with beneficial results in the manufacture of such articles as screws. Such steels have excellent upsetting and cold forming properties and therefore they may be readily headed as, for example, in screw manufacture.

When, prior to myinvention, relatively high contents of sulphur ready machineability frequently had surfaceseams, which caused were the used for conferring imperfections, such as difliculty in upsetting and cold forming operations and giving at times more or less unsatisfactory products. To prevent or nullify these imperfections additions of some deoxidant, aluminum for example, have been made,

but the resulting steel additions, frequently 5, as a consequence of these offered difliculties in machining. By my invention these obstacles to upsetting, cold forming and machining are overcome. Because of th surface or skin e rimming of the steel the is substantially free from the imperfections which have rendered upsetting operations diflicult and prisingly, the surface rimming, does the sulphur in tions. Obviously the uncertain and, rather surcondition, thus produced by not interfere .with the action of facilitating the machining operaemployment of this practic'e makes unnecessary the use of any considerofdeoxidants as heretofore and eflect of such additions on the machining qualities.

I employ steels having carbon contents up to 25%.. manganese up to .60%, and silicon preferably not exceeding .03%. The usual methods for making rimmed steel additions are prefer are employed. Aluminum ably avoided. Sulphur is steels thus produced added to the steel in the ladle after it has left the steel producing furnace, suflicient of this element being added to give a sulphur content in the finished steel of from .07% to .25%. Sulphur may be added in any desired form, as for example 5 as stick sulphur or as pyrites.

For wood screw stock I employ rimmed steel preferably containing carbon from .10% to 20%, and sulphur from .10% to .16%, although I have obtained satisfactory results with sulphur as low 10 as .08% and as high as .18%. Such steels are readily adapted to upsetting operations and they thread easily giving accurate threads free from appreciable imperfections.

Rimmed steels containing carbon .06% to .12% and sulphur .07% to have given good results in the manufacture of machine screws, the results being especially good with carbon .06% to 10% and sulphur .08% to .12%. In making machine screws with these steels standard meth- 20 ods of manufacture may be employed. The properties due to the rimming of the steel facilitate the forming operations such'as upsetting and thread rolling without interfering with the effects of the sulphur in aiding the machining operations such as shaving and slotting of the heads.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. Screw stock of rimmed steel containing carbon up'to 25%, and sulphur .07% to .25% and the balance consisting substantially of iron.

2. Wood screw stock of rimmed steel containing carbon .10% to .20% and sulphur .08% to r .18% and the balance consisting substantially of 30 iron.-

3. Machine screw stock of rimmed steel containing carbon .06% to .10% and sulphur .07% to .14% and the balance consisting substantially of 40 iron.

'4 A ,wood screw of rimmed steel containing carbon .10% to 20% and sulphur .07% to .25%

and the balance consisting substantially of iron. 5. A machine screw of rimmed steel contain- 6. A machine screw of rimmed steel containing carbon up to ,12% and sulphur .07% to'.25% and the .balance consisting substantially of iron.

LOUIS H. wmmna.