US1338132A - Magnet-steel - Google Patents

Description

'UNITED STATES PATENT OFFICE.

KOTARO HONDA, OF YONEGA-FUKUBO, SEND AI, JAPAN, ASSIGNOR TO SUMITOMO OHUKOSHO, LTD, OF OSAKA, JAPAN, A CORPORATION OF TAP-AN.

MAGNET-STEE 1,338,132.. Ili'o Drawing.

To all whom it may concern:

Be it known that I, KOTARO HONDA. D. Sc.,

citizen of Ja an, reslding at No. 21 Kanoko Shimidzu, onega-fukuro, Senda1, Japan,

have invented certain new and useful Improvements in Magnet-Steel; and I do here by declare the fol owi td be a full, clear,

and exact description the invention, such as will enable others skilled in the art to which it appertains to make and use the same. i

This invention relates .to steels and to magnets made therefrom.

novel vma net ore particularly, the invention relates to 'the manufacture of permanent magnets from alloys comprising carbon steel, cobalt, and one or more metals of the chromium family.

Magnets made accordance with the in-' vention materially excel ma ets heretofore known especiallvin point 0 strong residual magnetism and arge coercive force.

In the particular embodiment of the invention here chosen for purposes of illustrating and explainingl the Ibtroarli pringiple? epa lcuarme a 0' involved, tungsten is t the chromium group. constituting an essential ingredient of the alloy, the use of chromium in addition to tungsten being very desirable but not essential. Inm copending application, Serial No. 197,838, led October 22,1917, is disclosed and claimed another specific embodiment of the invention in which chromium is the only metal of the chromium roup specified as an essential ingredienfl o the magnet steel in question;

.while in'an'other copending application Serial No. 197,839,filed October 22, 1917, is disclosed and claimed another specific embodiment of the invention in WhlCll molybdenum, and optionally chromium, are specified as ingredients of the alloy steel. In a typical instance, a magnetembodying the principles of the invention may be made of an alloy steel having the following ran e of composition:

obalt, 5-60%'; tungsten, 110%; chromium, (15-10% carbon steel, (with 0.52% carbon,) the remainder. Most desirably the cobalt content is from 20 to 60%, and,35% has been found particularly suitable.- The chromium, althou 'h a desirable constituent,

' may be omitted without seriously diminish- Specification of Letters Patent. Patented Apr. 27, 1920. Application filed October 22, 1917. Serial No. 197,837.

temperature for ordinary magnet steel which i is about 800 C. After quenching, the

,shaped body of paramagnetic metallicmaterial is strongly magnetlzed with the aid of a owerful magnet or coil.

he ma et produced in the manner described is ar superior to inagnets heretofore known in the art, particularly as regards (l) Coercive force which in magnets of the best ty' e heretofore known. does not exceed C. magnet, the specific coercive force reaches S. units, whereas in the present 200 C. G. S. units. For this reason, loss of magnetism or so-called magnetic decay, due

to" shock or lapse of time is exceedingly small in the case of the present magnet.

(2) Intensity of magnetization per unit volume, which in the known magnets of the best type rarely exceeds 450 C. G. S; units after artificial aging; Whereas owing to its lar e coercive force the intensity of mag netlzation of the Grpresent magnet commonly exceeds 700 C. S. units after artlficial aging.

The foregoing remarkable distinguishing characteristics of my new magnet obviously render the same capable of wide use to an increased extent in arts in which the magnet pla san important part.

at I claim is: 1. A method of preparing permanent magnets-which comprlses' quenching a body of paramagnetic alloy steel containing cobalt at a .temperature substantially above 800 -C., and thereafter magnetizing the same.

. 2. The methodof preparing permanent- .magnets which COIIIPI'lStES quenching a body of an alloy steel containing from about 5 to 60 per cent. cobalt, from aboutal to 10 per cent. tungsten, and fromabout 0.5 to 10 per I cent. chromium, at a temperature substantially above 860 0., and thereafter mag 5. The metbo of preparing permanent magnets which comprises quenching at a temperature substantially above 800 C. a body of an alloy steel containing cobalt and aiggsten and thereafter magnetizing said 6. The method of preparing permanent magnets which comprises uenchin'g at a temperature substantially a ove 800 C. a

body of .an alloy steel containin cobalt, tungsten and chromium, and t ereafter magnetizing said body.

7 In a method of reparing permanent magnets, the step whic COIHPI'ISBS queching a body of paramagnetic alloy steel containin-gcobalt at a temperature substantially above 800 C.

8. In a method of I magnets, the step whic comprisesquenching a body of an alloy steel containing cobalt and a metal of the chromium group, at a temperature approximating 1100 C.

reparing permanent 9. As a new article of manufacture, a

. magnetized body of an alloy steel contaim cobalt and a metal of the chromium g group;

10. As a new article of manufacture, a magnetized body of an alloy steel containing cobalt and tungsten. a

11. As a new article of manufacture, a magnetized body of an alloy steelcontaining cobalt, tungsten and chromium.-'

12.]As anew article of manufacture, a permanent ma et made of .an alloy" con taining from a out 5 to 60 per cent. cobalt, from aboutl to 10 per cent. t n, and carbon. steel of from about 0.5 to per cent. carbon.

13. new article of manufacture, a

permanent ma 'tainingfrom a out 5 to 60 per cent. cobalt, from about 1 to 10 percent. tungsten, from at madev of an alloy conabout 0.5 to 10 per cent. chromium, and carbon steel of from about 0.5 to 2 per cent. carbon".

14:. As a new article of manufacture, a

rmanent magnet comprisinga ma etize l i ody of an alloy steel containing fr o r n 5 to per cent. cobalt substantially uniformly distributed therethro h.

15. As a new artic e of manufacture,-a

- permanent magnet comprisinga magnetized body of 'analloy steed containing a substan tial percenta of cobalt substantially uniformly distri uted 'therethrough.

In testimony whereof I hereuntoaflix my ature." slgn KOTARO