US1987714A

US1987714A - High temperature thermostatic metal

Info

Publication number: US1987714A
Application number: US564268A
Authority: US
Inventors: Scott Howard
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1931-09-22
Filing date: 1931-09-22
Publication date: 1935-01-15
Anticipated expiration: 1952-01-15

Description

Jan. 15, 1935. H. SCOTT 1,987,714

HIGH TEMPERATURE THERMOSTATIC METAL Filed Sept. 22, 1931 ITN ss s: INVENTOR I -Hovmrd Scuff 1/ v ATTORNEY Patented Jan. 15, 1935 I I a i I UNITED STATES PATENT OFFICE 4 1,987,714 HIGH TEMPERATURE THERMOSTATIC METAL Howard Scott, Wllkinsburg, Pa., assignor to Westinghouse Electric 8; Manufacturing Company, a corporation of Pennsylvania Application September 22, 1931,8erlal No. 564,268 2 Claims. (01'. 291-15) My invention relates to thermally actuable deof a bimetal element of these alloys is relatively vices and particularly to bimetal thermostatic hard to accomplish and is, therefore, somewhat members. expensive. 1

Among the objects of my invention are the 101- Further experimental work along this line has lowing: To provide a bimetal combination of two indicated that the lack of ductility and the ex- 5 alloys of diflerent temperature expansivities that cessive hardness of the alloy including up to shall have of the same order'of hardness; to pro- 25% of manganese can be overcome bythe use vide a high expansion component in a bimetal of relatively larger manganese contents, and I element that shall be ductile and that shall not have found it possible to use up to substantially 10 have excessive hardness; to provide a bimetal 36% manganese, which is a greater percentage 10 combination that shall have suchcharacteristics than would theoretically have seemed desirable. as to the relative hardness of the two compo- One of the results accompanying the use of nents as will permit of fabricating the same rela higher percentage of manganese is that the atively easily; to provide a bimetal element that temperature a which its n ivity chan shall have a relatively large coefllcient of deflecr p y from a W V l to a hi h V l i m- 15 tion with apredetermined change of temperature. creased. The t mp ratur fli nt 0 pa In practicing my invention I provide a bimetal sion is, ho not Changed pp y from element made up of two iron-base alloys, the high that of the alloy containing not over 25% of expansion component being a manganese-iron manganese above about 200 C.

alloy having over 23% of manganese, while the It a higher deflection is desired at the lower 20 low expansion component is a nickel-iron alloy t mp atur s, I may Obtain the a y d n with which may be mixed an appreciable per- 8n alloyi g eleme t 01 t e Order Of 185$, centage of cobalt. The two components of such either singly or in combination, of nickel, copper,

a bimetal element may be operatively associated cobalt, chr mium. Silicon, molybdenum, 0 t

25 with each other in any desired manner usually sten, to the iron-base alloy containing 23% to 25 practiced in this art. 36% of manganesa without serious loss in due- Thesingle figure of the drawing illustrates a tility. It may be desirable to maintain the combimetal strip or bar embodying my invention and bined percentage of manganese and one or a comshown in section. bination of the above-enumerated metals so as In my Patent No. 1,671,491, I have disclosed and not to materially exceed that i n 30 claimed a high-expansion component for a bistantially 5% of one or of a combination of the. metal element that includes specifically an alloy above-enumerated seven metals is used, the perof iron embodying not over 30% of manganese, centage content of manganese should not exceed which is operatively associated with a nickel-iron 31% or 32%. This composition is set vforth in 35 alloy containing up to or approximately 45% combinationVI of TableIwhere the five percent 35 nickel. I have found that a bimetal element of of added elements is to be considered as including the kind disclosed and claimed in this patent has a group consisting of these metals used singly or desirable properties for use at temperatures havin combination. ing an average value of about 300 C. I have The single figure of the drawing illustrates a also found, however, that a bimetal combination strip or bar of bimetal in which the high-expan- '40 of thiskind, and particularly the high-expansion sion component 11 is a manganese-iron alloy component thereof, suffers from a lack of ductility embodying the composition hereinafter set forth and is excessively hard, so that the fabrication in Table I, while component 121s a nickel-cobalt- I TABLE I 45 High. expansion component Manganese Carbon Silicon egg g Percent Percent Percent Patent 1 I 28to36 .05to.30 .05tol.0 0M2 Do. I1 30 to 33 .05 to .30 .05 to 1.0 0 to 2 D0. III 30.5 .16 .17 0 to 1 Do. IV 28t036 .05t0.30 ..05tol.0 0tol Do. V 26to36 .05to.30 .05tol.0 0to2 D0. VI 23 to 31 .05 to .30 .05 to 1.0 l to 5 D0. 56

iron alloy which may be made up of any one of the combinations hereinbelow shown in Table 11.

hereinbefore stated, the coeillcient of deflection can be increased somewhat by the addition of an Tun: II I Low expansion component Added ele- Remainder Nickel Cobalt Manganese Silicon menu on Percent Percent Percent Percent Percent A 25to50 6 .06tol.0 .05to.6 Otol Do. B 29.8 16. 5 .22 .05 to .5 to 1 Do. 0 26to32 3t020 .05tol .05to.5 0to2 Do. D 35to60 .lto2 .05tol .05to.5 0M2 Do. E 45.2 .1 to 2 .06 to .53 .01 to .07 0 to 1 Do.

. have found it possible also to use substantially 30.5% of manganese, .15% of carbon, .17% silicon, less than 1% of incidental constituents with the remainder being iron and obtain substantially the same results as to ductility and hardness. By the incidental constituents, I mean the usual small quantities of impurities of one kind and another which are usually found to be present in an alloy or metal and which are of no particular effect as regards the particular characteristics which it is desired that the alloy or metal shall have.

Referring to the low expansion component set forth in Table II, it may be noted that I prefer to use more than 25% of nickel and may even use up to 50% of nickel, in combination with cobalt varying from 3% to 20%, from .05 to 1% of manganese, from .0l% to 5% of silicon, from a trace to 2% of incidental constituents, the remainder being iron or steel.

By virtue of the lower hardness and higher ductility of the higher-manganese, iron-base alloys, as compared to such alloys having about 23% of manganese, bimetal elements made from the former, in combination with a low-expansion nickel-steel, may be fabricated, as by being welded or fused one to another, relatively easily, and may then be much more easily rolled, either cold or hot, (than bimetal elements using the 23 percent manganese steel) to the desired degree of thickness. The bimetal element or slab thus acts, in general, as a single metal element or slab, that is, the initial relative thicknesses of the two components will remain the same no matter how alloying element which may be either one or a combination of metals hereinbefore enumerated, all of which have relatively high temperature expansivities, the amount or percentage of the alloying element being relatively small but very effective.

The difference in expansivities of the two components has been found to be not more than l2.0 per C. at 100 C. and greater than 15.0 10- per C. at 300 C.

Various modifications may be made in my invention without departing from the spirit and scope thereof, and I desire, therefore, that only such limitations shall be placed thereon as are imposed by the prior art or are set forth in the appended claims.

I claim as my invention:

1. A bimetal element including two cooperating components having different temperature expansivities, the high expansion component being an alloy including from twenty-six to thirty-six percent of manganese, between one tenth percent to one percent of incidental constituents, from one to five percent of any one of the following or any combination thereof; copper, cobalt, chromium, nickel, silicon, molybdenum, tungsten, the remainder being principally iron, the low expansion component being an alloy including between twenty-flve to fifty percent nickel, approximately fifteen percent cobalt, between one tenth percent and one percent incidental constituents', the remainder being principally iron.

2. A bimetal element including two cooperating components having difierent temperature expansivities, the high expansion component being an alloy including substantially thirty and one half percent of manganese, approximately fifteen hundredths percent of carbon, approximately seventeen hundredths percent of silicon, between one tenth and one percent of incidental constituents, between one and five percent of an alloying element from a group consisting of copper, cobalt, chromium, nickel, silicon, molybdenum, tungsten, the remainder being mainly iron, the low-expansion component being an alloy including twenty-nine and eight tenths percent of nickel, approximately fifteen percent of cobalt, approximately twenty-two hundredths percent of manganese, between one tenth and one percent of incidental constituents, the remainder being principally iron.

HOWARD SCOTT.