US1864567A

US1864567A - Alloy of azotized character

Info

Publication number: US1864567A
Application number: US394136A
Authority: US
Inventors: Richard R Walter
Original assignee: Individual
Current assignee: Individual
Priority date: 1929-08-05
Filing date: 1929-09-20
Publication date: 1932-06-28
Anticipated expiration: 1949-06-28

Description

Patented June 28,1932

UNITED ra l-Es ATENT oFrica' RICHARD R. WALTER,- OF 'S'I'ABNBEBG, GEMANY ALLOY or azorrzsn cnaaacran No Drawing. Application filed September so, 1929, Serial in. $94,136, an in Germany Au ust- 5, 1929.

My invention pertains to sintered alloys of the class which include a carbide, a nitride or a carbonitride of a metal or metalsof the chromium group and which-while hard are also tough bylreason of the inclusion of aux- .iliary metal or, metals either from one or more groups and more particularly pertains to an alloy containing azotized, nitride'd or nitrified metal from either one, or metals from IOboth', of the iron and chromium groups.

It is known that hard alloys principally consisting of carbides and nitrides or car- 'bonitrides of the chromium group are often manufactured by mixing with lower melting 19 metals ofeither or both of the iron and chromium groups, pressing of the p0wd'eredin gredient's and thensubjecting them to a sintering process. z e

The auxiliary metals are purposed to cause the individual particles of the main mass for-example, the carbidesetc. to stick to'%ether as one tenacious piece uch alloys find principal use as tools or arts which are subjecxged to severe wear. owever the auxiliary etals, which are in "every case, softer than the material of the main mass, as for example, the carbides, nitrides etc. reduce the tenaciousness of the alloys against wear or their resistance to wear and it is for, that reason that the ainount of auxiliary metal to be added is restricted.

It was discovered that this harmful effectof the auxiliary metals can he avoided and their resistance to wear noticeably enhanced if, one employs them-in the formof azotides i. e. as metals combined with nitrogen. The auxiliary metals of the iron group (Fe,Mn, Ni, Co) or these in combination with metals of the chromium group (Cr W, Mo, U) according to this invention first subjected to azoti'za'tion (in.a manner excepting tlmgsten means of dissociated nitrogen while in their powdered condition and before their mixture with the elements to be sintered. In the case of ,tungsten'the azotization requires also the simultaneous presence of hydrocarbons.

I have made the discovery that the nitrification is consummated with mar'kdly greater facility and is also possible with by itself previously known and suitably by such mot alswhich heretofore resisted it, "especially with all metals of the iron group (iron, manganese, cobalt and nickel) and of the chromium group (chromium, tungsten, molybdenum and uranium), when the nitrification proceeding follows a superficial carburization or when thecarburization occurs simul taneously with the nitrification.

Because the melting temperature generally rises in proportion as the nitrogen content increases, one does not carry the azotization 'so far as to make the subsequent sintering process more difiicult.

It was discovered for instance, that even a content of five-hundredth per cent of nitrogen (.05% N) produces a considerable in crease in the tenacity against wear. Expediently one should not use much over one per cent nitrogen (1% N), even thou h a still greater proportion can be usefu if one reckons with the consequential increase in the temperature required to sinter.

It was also discovered that the a'zotization of the aun'liary metals need not occur before their mixture with the primary elements, but 75 can also occur with equal successsimultaneously during the sintering procedure. The principalelements llke carbides or nitrides or carbonitrides are adequately mixedwith the auxiliary metals, as for example, iron, nickel or cobalt and tungsten or others in a powdered state, pressed to formed pieces. R and these sintered in the usual manner. The azotizatinn hen ensues during the sinterin process by assfige thereover of dissociate nitrogen" gas or ammonia (NH- gas I or else while one conducts the hydrogen (employed as a protecting gas) through an-am-f moniacal solution whereit becomes chargedwith ammonia (NH gas. The formpressed 'ecesto be sintered, in consequence of their 1 "sue porosity, exe'rt a considerable ca efi'ect to gases and the nitrogen] fiuses through the'entire cross section ofthe bodies. {As an example conformable to the inventionthe followin alloy is specified ':-seventy percent tungsten carbide, fifteen percent (15%) azotized tungsten, ten per-.

cent (10%) azotizedcobalt, three percent w (3%) ,azotized chromium.

'1 claim 5- 7 1. An alloy comprising principally a powtiered, pressed and sintered carbonaceous tungsten compound together with at least one r 5 homogeneously mixed azotized auxiliary metal of the iron or chromium group.

2. An alloy comprising p-rincipallya powtiered, pressed and sintered carbonaceous tungsten compound together with homogenel0 ously mixed azotized auxiliary metal of both the iron and-chromium groups.

3, An alloy according to claim 1, in which a mixture of azotized tungsten carbide and of an azotized metal of the chromium group 1 is em loyed. p p

4; alloy according to claim 1, in which is employed as auxiliary metal a mixture of azotized metal of the iron group and azotized metals of the chromium group. 2 5. An alloy comprising over fifty per cent of a carbide of tungsten and azotized auxiliary metals comprising one of the chromium group ofhigher melting temperature than said carbide and one of the iron grou of 25 lower melting temperature thanthe mefiing temperature of said carbide, the whole being inpowde red, compressed and sintered form.-

6. An" alloy is comprising over fifty (50%) per cent 'of a carbonaceous compound of Q metal ofthe chromium group and the remainder azotized tungsten, azotized cobalt and azotized chromium.

RICHARD RWALTER.