US2075718A - Heat-resisting implement - Google Patents

Description

mama Mar. 30, m7

UNITED .STATES PATENT orrlcs.

my, sohmctse aslignor to the ilnn Remus-Vacuum- Akticngelelhchait, Hanau-on-tho- Nb 1mm. Original application March 1, ms,

Serial No. 9,806.

March 24, 1984 Divided and this application July 7, 1088, Serial No. 89.372.

InGermany 2 Claims. (Cl. 75-171) This application is a division of my copending patent application Serial No. 9,806, filed Mar. '1. 1935.

This invention relates to heat-resisting imple- 5 ments constructed from alloys of metals of the iron group and the sixth group of the periodic system oi the elements.

The heat resistance oi implements constructed from alloys of metals of the iron group and the sixth group of the periodic system of the elements, e. g. constructed from chrome-nickel alloys is to be ascribed in the first place to the fact that the high chromium content in association with nickel forms a strongly adherent oxide layer which protects the remaining metal from buming. It was formerly supposed that the heat resistance oi implements constructed from such alloys could be considerably improved when elements more electropositive than nickel, the oxides of which are stable above 1500 C. were added thereto. It has, however, been shown that these considerations are by no means generally applicable and that although certain of these electropositive elements increase the heat resistance, others on the contrary do not. Thus, for example, the heat resistance 0! an implement constructed from a chrome-nickel alloy is considerably reduced by addition of titanium or also vanadium; even additions oi aluminum bring about improvements of the heat resistance only under particular conditions, whereas in small quantities they have disadvantageous influences. Since titanium and aluminum are nearly related to the rare earths, it was consequently to be expected that the latter analogously with the for-- mer elements would behave in a similar manner, that is to say would not give rise to any increase in the heat resistance of implements made of chrome-nickel alloys. Thorough research has now shown that these rare earth metals in contradistinction to titanium and aluminum have the property of increasing to a considerable extent the heat resistance of implements constructed from alloys of metals of the iron group and the sixth group of the periodic system of the elements, e. g. constructed from chrome-nickel alloys. Thus, for example, the life of a 0.4 mm. wire in the iorm oi a small spiral wound on a 3 mm. mandrel heated electrically to 1050 C. for alternate periods of two minutes with interposed breaks or 2 minutes, was about hours. A similar wire made 0! the same alloy with an addition or 02% ct a metal of the cerium group or 0.2% 01' "cerium mix'ed me i. e. cerium mixed or alloyed with other metals of the rare earths had a lite periodoi about 200 to 280 hours. Higher percentages of cerium give a corresponding increase in improvement except that with larger additions the effect is not wholly proportional to the amount introduced, a content of about 0.8- 1% of cerium or cerium mixed metal" giving about the maximum eiiect a content of 1.2% being the upper limit coming into consideration.

The additions of metals of the rare earths required for obtaining an appreciable increasing of the life period of heat resisting implements such as heating wires or hands for electrically heated furnaces, structural elements 0! the inner parts of heating and annealing furnaces, e. g. conveying chains, supporting sheet metal, pyrometer protecting tubes inc, need be very small, inasmuch as additions oi! 0.02 percent oi. rare earth metals to the molten base metal or a content of 0.01% in the final alloy already suiiice to give a noticeable eiiect. The base metal tor the heat resisting implements to which the rare earth metals are added may contain besides metals of the sixth group of the periodic system 0! the elements metals of the iron group as the main constituent, namely 50 to 98% of nickel, and up to 48% of iron or iron plus cobalt, the amount of cobalt not exceeding 20% or the final alloy. The percentage of the metals of the sixth group of the periodic system of the elements namely chromium, molybdenum, tungsten and uranium may amount to 1 to 48%, the chromium contents being 1 to 30%; the amount of each of the metals molybdenum, tungsten and uranium should not exceed 20%. when several oi the elements cobalt molybdenum, timgsten and uranium are contained at the same time in the alloy, their sum should not exceed 20%. The alloys may further contain small additions for deoxidation or for improving the malleability such as manganese, magnesium or silicon each up to an amount of 2%, the sum of these additions not exceeding 2%.

I claim:-

1. As an article of manufacture and trade a heat resisting implement constructed of a chrome-nickel alloy consisting of from 1 to 30% of chromium and from 0.01 to 1.2% oi metal of the cerium group, the remainder being nickel.

2. As an article 01' manufacture and trade a heat resisting implement constructed of a chrome-nickel alloy consisting of irom 1 to 30% 0t chromium and from 0.01 to 1.2% of cerium, the remainder being nickel.

WERNER 2 CERTIFICATE OF CORRECTION.

Patent No. 2,075,718. March so, 1957.

WERNER HESSENBBUCH.

It is hereby certified that the name of the assignee in the above numbered paten't was erroneously written and printed as "Heraeus-Vacuumschmetze Aktiengesellschaft" whereas said name should have been written and printed as Heraeus-Vaouumschmelze Aktiengesellschaft, as shown by the records of assignments in this office; and that the said Letters Patent should be read with this correction therein' that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 8th day of June, A. D. 1937 Henry Van Arsdale (Seal) Acting Commissioner of Patents.