US2349577A - Control member - Google Patents

Description

@Y 23 w44- R. s. DEAN CONTROL MEMBER 7 7 5, 9 QW Z Filed Nov. 21, 1941 2 Sheets-Sheet l ATTORNEYS patented May 234, i944 EL, @al

tit aryl 2.349,57? contract.. '1i/rayman application November 2l, lllll, Serial No. @9,872

' (ci. asiisi 2i claims.

This invention relates to thermostatlc elements in the form of alloys of a high coefficient of expansion. lt relates more, in particular, to alloys having a high tensile strength and yield point in combination with a high coefcient of linear expansion and to thermostatic metals, particularly bimetals, of which the high expansion members are the manganese, nickel, copper alloys disclosed hereinafter. The alloys or thermostatic metals to which the invention relates have as constituents manganese, nickel and copper. l The invention will be explained, in part, by reference to the accompanying drawings, wherein Fig. l is a ternary diagramvshowing a, number of curves illustrative of the linear expansion characteristics of the alloys; and

Fig. 2 is a similar diagram identifying certain areas.

In Fig. l, I have illustrated the coeflcients of linear expansion by lines of equal coemcients drawn on a ternary diagram representing the three component system, manganese, nickel and copper. Although the manganese, copper, nickel alloys vdisclosed herein are highly useful for the purposes ot the present invention without any heat treatment, those illustrated in the diagram were prepared by quenching from 900 degrees C. and subsequently cold working them. The coefficients of expansion of the alloys as quenched and cold worked are not greatly affected by subsequent heat treatment. In the following table, l show the coemcients of linear expansion of several speelde alloys in both the quenched and cold vvorlred states, and also after aging at t5() degrees C. In this particular case, the measurements were made from room temperature to 100 degrees C.

Coeicieat of linear eaptmsionxlw cm./cm./ C.

Composition uenched 4 Qand con Qualche? 450 Worked from 900 Mu Nl Cu 75 2O 5 24. 7 26. 3 25. 3 75 5 20 23. 24. 5 22. 5 10 65 16. 8 19. l 16. 4 20 20 14. 9 17. 5 15. 2 30 0 22. 5 22. 21. 9 Q0 5 v 5 14. 5 22. l l5. 72 l0 18 25. 1 28. 3 21. 5

n1 audition to tne'mgn menaient of nnen ea-l pansion which is illustrated by the values given, l have found that these alloys possess other vai able properties which make thern useful in ary ticles where high coeihcients of linear expansion are necessary. As indicated by the table, certain of .the alloys of my invention may be hardened by heat treatment. The extent of this hardening and the preferred heat treatment for bringing it about diller in dierent composition ranges.

In llg. 2, l 'have illustrated several ranges of composition which have been designated by outlining areas identified by the letters A,.B and C. ln the compositin range within the area A, I have found that a suitable treatment to develop liigh strength and yield point 1s to heat to a temperature of about 900 degrees C., quench and then age at about 450 degrees C. A cold working step or steps may be introduced between the quenching and aging steps. As a result of this heat treatment, these alloys may be given tensile strength oi' l50,000 to 200,000 pounds per square inch and a yield point of 75% of the tensile strength. Even higher tensile strengths may be obtained, but the yield ypoint then as a rule is closer to the value for ultimate tensile strength.

In the composition range B, a suitable heat treatment is to quench the alloys from about `S900 degrees C. and then ageat a temperature of 700 degrees C. Under these conditions, these alloys have greatly increased hardness imparted to them. y

In the composition range C, a suitable heat treatment is to quench the alloys from about 900 degrees C. and age them at a temperature of 600 degrees C. With this treatment of the alloys in this range, tensile strengths of 120,000 pounds per square inch may be obtained. I have found that the alloys ci my invention possess high electrical resistance and that the electrical resistance may be considerably enhanced by quenching from a temperature of about 900 degrees C. Thequenched alloy may be cold worked Without adversely aecting its electrical resistance.

l have found that there ls an approximate parallelism between electrical resistance and coecient of linear expansion in the alloys of my invention. l. have found, for example, that alloys having electrical resistances between and 200 l06 ohms/cin.3 show a coefcient of linear expansion in excess of 20x30- cin./cm./de gres C. and that the alloys having an electrical resistance of less than l50 10s ohms have a coefdcient of linear expansion of approximately l5 10r6 emmers/degree C.

I have found that aging at 450 degrees C. adversely alects the electrical resistance n the Vaccordance with theusual practices.

alloys within the composition range indicated by the area A in Fig. 2, while in the area B of Fig. 2, the electrical resistance may be greatly enhanced by heat treatment. A suitable treatment to develop very high electrical resistances in alloys within the area B, is to quench from 900 degrees C. and reheat at a temperature of '700 degreesC'. for several hours. By this treatment, electrical resistances as high as 2000 6 ohms can be obtained.

'I have found that the maganese, nickel, copper alloys have relatively low temperature coefficients of electrical resistance. This property is especially low in the alloys having coemcients of linear expansion of approximately l5 lil-6 cm./cm./de gree C. and in the alloys having coelcients of linear expansion of more than x10-6 cm./cm./degree C. All of these alloys have a relatively' high modulus of elasticity. Many of them have a modulus of more than 20,000,000 pounds per square inch. Il'hese alloys also possess high fatigue strength. These various properties, combined with high ccemcients of linear expansion, make the alloys of my invention particularly useful, for example, as bi-metal strips for temperature control work. In such strips it is important not only to have a high coeiiicient or" linear expansion, but also to having a high, yield point and modulusvof elasticity. High vibration damping capacity is also of value in materials for this use, since it may prevent chattering of the electrical contacts which are frequently made by the use of such strips. A high cocillcient o electrical resistance combined with a high coeihcient of linear expansion is very useful in ceraerial-wv temperature responsive device may ,take the form of known mechanical arrangements such as a rod within a tube.

Another type of control unit is one where the expansion of a single material, e. g., a bar, is utilized for control purposes. With the high electrical resistance obtainable with our alloys,

tain types of electrical equipment where it is advantageous to utilize the expansion of a member when it is heated by the passage of an electrical current. The properties of these alloys make them of extreme value in various types of temperature and electrical control members in the various industries in which such control members are used.

As an illustration, reference may be made to loi-metallic strips responsive to temperature changes. A conventional type of strip is one consisting of a low expansion component in the form, of a high nickel alloy such as Inval', with a high expansion component such as brass, copper or certain nickel, chromium, iron alloys. By employing a high nickel alloy, such as Invar (64% iron, 36% nickel), having a low coemcient of linear expansion, and one of the alloys of my invention having a coemcient of linear expansion of about 25 or higher l0B cm./cm./degree C., I can obtain about twice the movement per unit of temperature change as compared with the conventional strip. Imay also use an ordinary steel in combination with the high expansion alloys of inyY invention, and obtain considerable advantages. The low expansion component or member, while most suitably Invar or other ironnickel alloys having a high content of nickel, of the order of about 36% or higher, may be any other metal or alloy, illustrative examples thereof being disclosed in Patents Nos. 1,947,065 and 1,991,438. My alloys may be produced with a modulus of elasticity of better than twenty million, a ligure substantially in the steel range. In producing the loi-metallic strips, they may be welded, fused, brazed or otherwise handled in While I have mentioned bl-metallic strips as illustrative, it will be understood that such strips or members may comprise more than two laminae, or the the control member may carry a current and may be used in a circuit where rise of temperature produced through resistance of the member causes such linear expansion of the control member as to open a set of contacts and interrupt the current. In such a system, the member is directly responsive to current input. Other specic installations `of this general type maybe used. It will be understood that the invention is broadly applicable to thermostatic mechanisms where the manganese, nickel, copper alloys comprise the high expansion component of the differential expension portion of such mechanisms which utilize a diierence in the thermal expansion of two or more materials. i

The composition of the alloys used in accordance with my present invention, where the various properties discussed may be obtained, is

clear from the description alone as well as when l taken with the drawings.. The several properties obtainable should obviously be considered in the design of a control element. The drawings show that at least 10% manganese should be present, but that the manganese may comprise in some cases as much as 97% of the whole. The proportion of copper may be varied greatly as well, but the nickel content should not be more than 70% of the total composition. One satisfactory group of alloys comprises those containing from 3% to 26% nickel, from 2% to 25% copper, and from 67% to4 80% manganese, the total of said metals amounting to substantially 100%. Another range of excellent properties comprises those alloys containing from 8% to 20% nickel, from 7% to 19% copper, balance substantially all manganese, especially electrolytic manganese of high purity. A particularly satisfactory group of alloys comprises those containing from about 70% to 75% manganese, from about 8% to about 15% nickel, and from about 15% to 20% copper. Of especial value is an alloy of about 72% manganese, about 10% nickel and about 18% copper,

4Letters Patent of the United States is:

l. As a new article of manufacture, a control member adapted to expand and contract on heat,- ing and cooling, respectively, comprising metallic members having different expansion characteristics, one of said members being made of an alloy of manganese, nickel and copper, said alloy having a temperature coeilcient of expansion greater than 20x10-8 cm./cm./degree C. and comprising from 67% to 80% manganese, from 3% to 26% nickel, and from 2% to 25% copper, the total of the manganese, copper and nickel amounting to substantially 100%.

2. As a new article of manufacture, a control member adapted to expand and contract on heating andl cooling, respectively, crising metallic members having dierent expansion characteristics, one of said members being made of analloy of manganese, nickel and copper, said alloy having a temperature coefcient of expansion greater than 20X lil-ii cm./cm./degree C. and comprising from 8% to 20% nickel, from 7% to 19% copper, andthe balance of said alloy being substantially all manganese, the total oi the manganese, copper and nickel amounting to substantially 100%.

3. As a new article oi manufacture, a control member adapted to expand and contract on heating and cooling, respectively, comprising metallic members having dierent expansion characteristics, one of said members being made of an, alloy of manganese, nickel and copper, said allot7 having a temperature ccemcient of expansion greater than 2il 1ll*3 cm./cm./degree C. and comprising from-'70% to 75% manganese, from to 15% nickel, and from 15% to 26% copper, the total of the manganese, copper and nickel amounting to substantially 109%.

t. As a new article of manufacture, a, Icontrol member adapted to expand and contract on heating and cooling, respectively, comprising metallic members having different expansion characteristics, one of said members being made of an alloy of nickel, copper and manganese, said alloy having a temperature coemcient of expansion greater than 29x19-a cm./cm./degree C. and

nickel-iron alloy having of the order of at least 33% nickel and having a low coemcient of linear expansion, and the other one being made of an alloy ci nickel, copper and manganese, said alloy having a temperature coeicient of expansion greater than i0 cm./cm./degree C. andv comprising from 3% to? 26% nickel, from 2% to copper, and from 67% to 80% electrolytic manganese having a purity oi the order of 99.9%, the total of the nickel, copper and electrolvtic manganese of said alloy amounting to substaning a temperature coemcient of expansion greater comprising about 10% nichel, about 18% copper,

and about 72% manganese.

5. As a new article ci manufacture, a control member adapted to expand and contract on heating and cooling, respectively, comprising metallic members having dlerent expansion characteristics, one oi said members being made of a high :nickel-ironv alloy having a low coemcient of linear expansion, and another of said members being made of an alloy ci nickel, copper and manganese, said alloy having a temperature coefcient of expansion greater than 20x10"6 cm./cm./degree C. and comprising about 10% nickel, about 18% copper, and about 72% manganese.

6. As a new article of manufacture, a control member adapted to expand and contract on heating and cooling, respectively, comprising metallic members having different expansion chateristics, one oi said members being made of Invar and another of said members beingmade of an alloy oi nichel, copper and manganese, said alloyl having a temperature coeihcient oi expansion greater than acxiii-il cm./cm./degree C. and comprising about 19% nichel, about 19% copper, and about 72% manganese.

7. .as a new article o1 manufacture, a control member adapted to exd and contract on heating and cooling,'respectively, comprising metallic members having diderent expansion characteristics, one of said members being e oi Inval' and the other one being made of alloy oi nickel, copper andmanganese, said alloy having a.r temperature coefilcient of expansion greater than ;?(l 1ll6 cm./cm./degree C. and comprising from 3% to 26% nickel, from 2% to 25% copper,

and from 67% to 80% electrolytic manganese of at least 99% purity, the total oi the nickel, copper and electrolytic manganese of said alloy amounting to substantially 100%.

s. As a new article of manufacture, a control member adapted toexpand and contract on heating and cooling, respectively, comprising Ymetallic members having dierent expansion characteristics, one of. said membersbeing made oi a lrio than 25x16-6 cm./cm./degree C. and comprising from 3% to 26% nickel, from 2% to 25% copper, and'from 67% to 89% manganese, the total of the nickel, copper and manganese amounting to substantiall,y 199%.

10. As a. new article oip manufacture, a control member adapted to expand and contract on heating and cooling, respectively, comprising metallic members having dierent expansion characteristics, one oi' said members being made of a low expansion material and the other of said members being made oi a high expansion material in the form oi an alloy of manganese, nickel and copper, said alloy having a temperature coefficient oi expansion greater than 220x104 cm./cm./degrec C. and an electrical resistance ci at least 170 1il ohms/cm3, and comprising from 67% to manganese, from 3%l to 26% nickel, and from 2% to 25% copper, the total of the manganese, nickel and copper in said alloy amounting to substantially 1ilc%.

11. As a new article oi' manufacture, a control member adapted to expand and contract on heating and cooling, respectively, comprising metallic members having dierent expansion characteristics, one oi said members being made of invar and the other ci said members being made of a high expansion material in the form of an alloy of manganese, nichei and copper, said alloy having a temperature coemcient oi expansion not substantially lesa than 2h x 1W cm./cm./degree C. and an electrical resistance or at least 10s ohms/cm3, and comprising from 79% to 7,5% manganese, from 9% to 15% nickel, and from 15% to 29% copper, the total of the manganese, copper and nickel in said alloy ounting to substantiallv iilin%.

i2. it bi-metal strip comprising a rst metallic member having a low coemcient of linear expansion and a second metallic member having a high coecient ot lin eupansio'n,` said second member being de from an alloy oi nickel, copper` and manganese, said alloy having a temperature `filicient ci exion greater than 20x10-6 cm./cm./clegree C., and comprising yfrom 70% to 75% electrolytic manganese ha i a purity of at least 99.9%.'llrom 9% to 15% nickel, and from 15% to 20% copper, the total of the manganese, copper and nichel in said alloy 'amounting to substantially 109%. v

13. l bi-metal strip comprising a first metallic member having a low cient of linear 'expansion and comprlsingan iron alloy containing a high proportion of nickel, and a second metallic member having a high cient of expansion, said second mber being mii-om an alloy of nickel, copper and manganese, said alloy having a temperature coecient of expansion cf at least about 25X 10-cm./cm./degree C., and comprising from 8% to 20% nickel, from 7% to 19% copper and the balance of said alloy being substantially all electrolytic manganese of high purity, the total of the nickel, copper and electrolytic manganese in said alloy amounting to substantially 100%.

14. A bi-metal strip comprising a ilrst metallic member made of Invar, and a second metallicl member made from an alloy of nickel, copper and manganese, said alloy having a temperature coefflcient of expansion of at least about 25x10- cm./cm./degree C., and comprising from 8% to 20% nickel, from 7% to 19% ccpper and the balance of said alloy being substantially all electrolytic manganeseof high /purity, the total of ,the nickel, copper` and electrolytic manganese in said alloy amounting to substantially 100%.

15. Thermostatic metal comprising a plurality of joined metallic laminations, one of said laminations having a relatively high coefiicient of expansion and comprising an alloy of the following constituents by weight: manganese in excess of 50% and up to about 90%, nickel 4% to 20%, balance substantially all copper, the copper comprising at least 5%; the other lamination having a, relatively low coeilicient of expansion.

16. In a. device responsive to temperature changes to perform work or mechanical movement, a plurality of metallic members, one of said members having a relatively high linear coeiicient of thermal expansion and comprising an alloy of the following constituents by weight: manganese in excess of 50% and up to about 90%, nickel 4% to 20%, balance substantially all copper, the copper comprising at least 5%; the other member having a relativelyl low linear ccemcient of thermal expansion and comprising essentially Invar, an alloy of iron and nickel.

17. Thermostatic metal comprising a plurality of joined metallic laminations, one of said laminations having a relatively high coefcient of thermal expansion and comprising an alloy of the following constituents by weight: manganese 60% to 85%, nickel.5% to 30%, balance substantially all copper, the copper comprising at least 7%, the other lamination having a relatively low coemcient of thermal expansion.

18. A thermostatic metal comprising a plurality of joined metallic laminations, one of said laminations having a relatively high coeicient of thermal expansion and comprising an alloy consisting by weight of about 72% manganese, 18% copper, and 10% nickel, the other lamination having a relatively low coefficient of thermal expansion.

19. A thermostatic metal comprising a plurality of joined metallic laminations, one of said laminations havinga relativelyhigh coefficient of thermal expansion and comprising an alloy consisting by weight of about 72% manganese, 18% copper, and 10% nickel, the other lamination consisting of Invar.

20. In a device responsive to temperature changes to perform work or mechanical movement, a plurality of metallic members, one of said members having a relatively high linear coefficient of thermal expansion and comprising an alloy of the following constituents by weight: manganese 60% to 85%, nickel 5% to 30%, balance substantially all copper, the copper comprising at least 7%, the other member having a relatively low linear coeicient of thermal expansion.

21. In a device responsive to temperature changes to perform work or mechanical movement, a, plurality of metallic members, one of said members having a relatively high linear coeiicient of thermal expansion and comprising an alloy of the following constituents by Weight: manganese about 72%.,-copper about 18%, and nickel about 10%, the other member' having a relatively low'linear coemcient of thermal expansion. l. REGINALD S. DEAN.

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