US2029724A - Nitrided steel and a process for its production - Google Patents

Description

Patented Feb- 4, 1 936" V UNITED" STATE PATENT OFFICE NITBIDED STEELAND A PROCESS FOR ITS PRODUCTION I Wilhelm rn-eu. Luxemburg, Luxemburg No Drawing. Application January 6, 1931, Serial No. 506,973. In Germany January 18, 1930 11 Claims. (omit-1c) The invention relates to nitrided steel and a Itis well-known that invar-steels contain about process for its production. 36% of nickel It is already known that iron as well as certain iclaim: alloyed steels can be superficially nitrided by 1. As a new article of manufacture, a steel havheating in a current of ammonia at temperatures ing a nitrided surface layer and containing from 5 between 500 and 800 C. (nitriding) In par- .1 to 5% of beryllium, the principal portion of the ticular chrome-aluminium steels are nitrided at remainder being irOua temperature below 580 at which there is still 2. As a new article of manufacture, a steel havproduced no coating tending to form splinters. ing a nitrided surface layer and containing from The invention relates to the use of beryllium- .1 to 5% of beryllium, and about from to 12% 0 containing steels such as nitrided steels and to a of nickel, the principal portion of the remainder process for the nitriding of these steels. By being iron. means of experiments it has been found that 3. Asanew article of manufacture, asteel havberyllium-nitrided steels possess great technical ing a nitrided surface layer and containing from advantages. g

i As is well known beryllium'steels, in particular nickel and about from 10 to of chromium, those alloyed with nickel, also chrome-containthe principal portion ofthe remainder being iron. in beryllium steels will age ifafter chilling from. As a ewj u a ture; a steel ahighe'r range of temperature they are subjected chil ed fr m a t m ratu e above that of aging 20 to the so -called artifloial'ageing, that is to say and subsequently heated in an atmosphere con- 20 to a subsequent heat treatment at temperatures tainine' nitrogen to mp tur f fr m 4 between about 400 to 600913. The chilled beryl-1 C- until ni o n ha p netratedlnto its lium steels by such ageing process attain their surfacet'o form a nitrided layer, d S l 00ngreat hardness at those temperatures at which taining from t f eryl m, 'prig cip nitriding is conducted. Consequently according portion of the remainder being iron. to the invention it is possible by nitrid'ing to coat 5. As a new article of m ufa r a st e a beryllium steel which in the aged state has a ch d m a mp r u ebOVe that 0! in hardness of BOO-700 Brinell, with a coating as and subsequently heated in an atmosphere conhard as glass, which is impossible with the orditaining nitrogen to a temperatureof from 400 to nary chilled steels because the steel is already 600 C. until nitrogen has penetrated into its annealed by the nitriding temperatures. By the 1 form 8; n y r, Said St el 6011- use of my invention I can produce a metal body tami g from .1 to 5% f b ryllium a db0u or article which possesses a core as hard as steel from 10 to 1.2% of nickel, the principal portion and a surface as hard as glass. As, furthermore, -0f the remainder bein l beryllium has a rather' considerable amnity for 6. As a' new article of manufacture, a steel nitrogen the carrying out ofthe nitriding process c lled ronts tempera ure above that of aging is facilitated and generally"speaking the work and subsequently heated in an atmosphere concan be done with nitriding temperatures of taining trogento a temp of from 400 to 500 0. 600 C. until nitrogen has penetrated into' its .1 to 5% of beryllium, about from 10 to 12% of 15.

t It ispossible bya single operation, to age berylsurface to form a nitrided layer, said steel con-; 40 I lium steels artificially and.at the same time to taining from .1 to 5% of ry m f nitride them If desired, howev'erfthe nitriding t0 of nic a a ut f 'Om 10 O- .01 can be effected after the artificial ageing of the chromium, th'e'principal portion of the remainder beryllium steels. bein iron.

It has been found that the best results are ob- "7 The process of improving the, hardness of tained when the percentage of beryllium is be steel containing from .1 to 5% .of beryllium, the tween 0,1 and5%. In some cases somewhat more principal portion of the remainder being iron, or somewhat less beryllium can beused, Espewhich process consists in chilling the steel from cially favourable properties areexhibited by aa temperature above that of. aging and subsenitrided steel with 10-12% nickel, say with about quently nitriding it superficially while heating it justas much chromium arid 1% beryllium. The to a temperature of from 400 to 600 C. percentage of chromium may if desired be in- 8. The process of improving the hardnessof f creased to over 20%. Invar-steels are also capa steel containing from .1 to 5% of beryllium and ble of being nitrided provided they contain about from .10 to 12% oif niclrel, the principal beryllium. portion of the remainder being iron, which pr0'0- 5 ess consists in chilling the steel from a temperature above that of aging and subsequently nitriding it superficially while heating it to a temperature of from 400 to 600 C. I

9. The process of improvingthe hardness of steel containing from .1 to 5% of beryllium, about IromplO to 12% of-nickel andabout from 10 to 20% of chromium, the principalportion of the remainder being iron, which processconsists in chilling the steel from a temperature above that of aging and subsequently nitriding it superficially while heating it to a. temperature of from 400 to 600 C. to produce a nitrided surface.

. 10.:As anew article of 'manufacture, a steel having a nitrided surface layer and containing from .1- to 5% 01' beryllium,

and about 36% of nickel, e principal portion oi the remainder being n- 1'1.'As a newarticle of manufacture, a steel chilled from 'a temperature above that of aging subsequently heated in an atmosphere containing nitrogen to a temperature or from 400 tocoo" 0. m nitrogen has penetrated into its steel surface to form a nitrided layer, said steel-containing from .1 to 5% ol beryllium and about 36% of nickel, the principal portion 01' "the remainder being iron.

12. The process-of improving the hardness of containing from .1 to 5% or beryllium and about 36% of nickel, "the principal portion of the remainder being iron, which process consists in chilling thesteel from a temperature above that of aging and subsequently nitriding it superficially while-heating it to a temperature of from 400 to 600 C. 1

13. As a new article of manufacture, a nickelalloy steel having a nitrided surface layer and containing from .1 to 5% of beryllium, the principal portion of the remainder being iron.

14. As a new article of manufacture, a nickelchromium-a oy steel having a'nltrided surface layer and co 'tainin'g from..1 to'5% of beryllium, the principal iron..

" mm rmbm} portion of the remainder being a