US1901018A

US1901018A - Treatment of magnetic alloys and products resulting therefrom

Info

Publication number: US1901018A
Application number: US594155A
Authority: US
Inventors: Bieber Clarence George
Original assignee: International Nickel Co Inc
Current assignee: Huntington Alloys Corp
Priority date: 1932-02-19
Filing date: 1932-02-19
Publication date: 1933-03-14
Anticipated expiration: 1950-03-14

Description

alloys to increase the perature of about 2000 'creasin Patented Mar. 14, 1933 CLARENCE GEORGE IBIEBEB, 0F REMINGTON,

NTf-OFEIQE INTERNATIONAL NICKEL COMPANY, 1110., OF NEW YORK, 11'. 21-, A CORPORATION OF DELAWARE rnmmnur on'imemc rumors AND rnonuc'rs nrsun'rme Emma No Drawing.

This invention relates to a process of treating magnetic alloys-and more particularly'to a method of heat treating alloys of the nic eliron type to increase the permeability thereof, and to the new products resulting therefrom.

An object of the resent invention is to provide a method 0 heat tre'atin magnetic A- further object 0' the invention is to provide a simple and 1practical method of heat;

treating magnetic a oys of the nickel-iron type which can be carried out satisfactorily on an-industrial scale.

It is, another object of the invention to provide a method of heat treating magneticalloys particularly permallo like so as to increase the permeabi ity thereof several times greater than that of the commercial alloys on the market while only inthe cost of production a practically ne ligi 'le amount.

ther objects bf the invention will become clear from the description ofa specific procedure for carrying the invention into practice.

A magnetic alloy of the iron-nickel type such as permalloy is produced in the usual way. After production, the alloy is prefer ably fabricated into the form. in which it is to be used. For example, the alloy may be rolled into sheets. Care should be exercised at this stage of the operation to clean the fabricated magnetic alloy and free the same from grease before annealing.

The magnetic alloy of the permalloy. type is subjected to an initial super-annealing treatment in which a super-temperature is employed for a period of time scient to produce the new results of the present invention. In practice, it has been found that subjecting the magnetic alloys to a super-tem- F. to about 2200 F. is satisfactory when maintained for a period. of time from about 4 hours to about 8 hours. Following this initial super-annealing treatment, the alloy is preferably slowly cooled. By slow cooling is meant cooling at a rate slower than 1000 il per hour. lit should be noted that the initial super-annealing and ermeabihty thereof.

and the Application filed February 19, 1982. Serial No. 594,155. I

the slow cooling should be carried ,out' ina hydrogen orequlvalent atmosphere.

The cooled magnetic alloy is reheated in air to a temperature of about 1000 F to about 1200 F. for a period of time of about wns'r vmonmn- ASSIGNOR no man.

10 minutes to about 20 minutes- The reheated magnetic alloy is then rapidly cooled on a copper plate which initially has a temphere. Instead of using a coppen plate, a moist cloth can beused for rapidly cooling the'heated magnetic-material.

- The magnetic alloys produced by the foregoing procedure have been found to possess far greater permeability'than the same alloy when subjected to the old conventional heat ""perature approximating that of the atmostreatment. On the average, it has been found that the permeability of'the magnetic alloy subjected to the heat treatment of the present invention is at least two to three times greater than the permeability ofthe same magnetic alloy when subjected to the heat treatment. At the same time, the cost of producing the greater permeability in the magnetic alloy is very slight and is practically negligible when compared with the selling price of the allo A specific example will now be described of carrying the invention into practice on an industrial scale. It is to be noted, however, that theexample is merely for illustrative purposes and for a better understanding of the invention for those skilled in the art.

A magnetic alloy of the permalloy type composed'of about 78 76 nickel and about 21%% iron is cleaned and is free from grease. It is preferred to coat the sheets or the like of magnetic alloy with a refracold conventional,

till

F. This super-anancetype of furnace. By maintaining the a sheets at the super-annealing temperature of 2000 F. for a period of about 4 hours, the new results of t e present invention may be obtained.

The sheets heated to the super-annealing temperature are slowly cooled in'the furnace preferably in a hydrogen atmosphere. After subjected to the foregoing procedure were found to give surprisingly high permeability. These permeabilities were in each case at least three times greater than the permeabilities of the same alloy when subjected to the old conventional heat treatment. The following table gives figures which clearly illustrate the new results produced by the present invention.

Table Maximum permeabilitiea of nickel-iron alloy of permalloy type Basic electric furnace melts Old heat treatment New heat Mel treatment Acid electric furnace melts Old heat treatment New heat Melt treatment Acid open hearth mella Old heat treatment New heat ,Melt treatment Y-au From the foregoing table, it will be appreciated'that the permeabilities given. for the magnetic alloys when subjected to the old conventional heat treatments approximate those of the commercial magnetic alloys of the permalloy type now on the market. The figures given for the magnetic alloys of the permalloy type show that the present invention produces permeabilities which are far in excess of those of old conventional alloys. In eneral, the present invention ives permea ilities from about two to a ve five times higher than those given by conventional heat treatments. The benefits to be enjoyed by the art from the present invention are" the present invention and the 1m roved magnetic alloy with super-permeabi ities can be that other alloys of nickel-iron composition will be greatly enhanced in their permeability by employing the method of heat treatment herein. V

For instance, alloys having nickel from 65% to 80% and the balance iron show' increases in permeability in accordance with the following table Mari mum permeability New heat treatment Old heat product is simple and neither difiicult nor lengthy in application, but it does permit production of a product having great value and permits this production with very little increase in cost, and practically no increase in cost when considering the value of the new product. 7

It will also be observed that the present invention provides a process wherein permeabilities can be obtained which are in excess of 120,000; 150,000; 200,000 and even 300,000. a

'Withnickel-iron alloys of the permalloy it will be observed from'the first table t pe t at a magnetic product can be produced of a super-annealed nickel-iron alloy of the' permalloy type having permeabilities of at least 200,000.

It will alsoebe noted that the present invention provides a process which can be carried out on an industrial scale and which is capable of producing consistently and repeatedly magnetic alloys havinga ermeability in excess of industrial magnetic products which have heretofore been commercially available.-

Whatisclaimedis: 1. The. process of heattreating magnetic alloys of the nickel-ironjtype, which comprises subjecting such alloys to an initial super-annealing treatment, slowly cooling the super-annealed alloys in a hydrogen atmosphere, reheating the cooled alloys to about 1160 F. in air, and rapidlycooling I 0 about 4 hours at a temperature of about 2000 netic alloys treated with conventional heat alloys of 3. An article of manufacture comprising an industrial magnetic product composed of a nickel-iron alloy having a permeability in F., slowly coolingthe super-annealed alloy in an atmosphere of hvdrogen, reheating thev cooled alloy to a temperature of about 1160 F. for about 15 minutes and then rapidly cooling the thus reheated alloy on a copper plate having atemperature approximating that of the atmosphere, whereby the magnetic permeability of the alloy is increased several times greater than the permeability of mag treatments.

excess of at least 200,000.

4. An article of manufacture comprising an industrial magnetic product composed of a nickel-iron alloy having a permeability in excess of at least 300,000.

5. An article of manufacture comprising an industrial magnetic product composed of an iron-nickel alloy which has been superannealed in a hydrogen atmosphere to impart a permeability in excess of 150000.

. 6. An article of manufacture comprising an industrial magnetic, product composed of aniron-nickel alloy which has been superannealed, slowly cooled in ahydrogen atmosphere, reheated in air to a high tempera: ture' and then rapidly cooled on a copper plate to impart a permeability to the product in excess of 150,000.

7. An article of manufacture comprising an industrial magnetic product composed of an iron-nickel alloy which has been superannealed at a temperature of about 2000 -F. for about 4 hours, slowly cooled in an atmosphere of hydrogemreheated in air to a tempcrature of about 1160 F. for about 15 min.- utes and rapidly cooled on a copper plate to impartto,the product a permeability in excess of about 150,000.

8. An article of manufacture comprisin an industrialmagnetic product composed o an iron-nickel alloy nickel to about 80% nickel and the balance iron, which has been super-annealed in a hydrogen atmosphere to impart a permeability in excess of 150,000.

9. An article of manufacture comprisin an industrial magnetic product composed 0 an iron-nickel alloy consisting of about nickel to about nickel and the balance iron, which hasbeen super-annealed to impart a. ermeability in excess of 200,000.

10. an industrial magnetic product composed 0 an iron-nickel alloy consisting of about 7 5% nickel to about 80% iron, which has been super-annealed to impart a permeability in excess of 300,000.

11 article of manufacture comprising,

nickel and the balance 11. In the art of heat treating magnetic alloys of the nickel-iron type, that improvement which comprises subjecting the nickeliron alloy to an initial super-annealing treatment in a hydrogen atmosphere substantially free from moisture and oxygen, slowly cooling the super-annealed alloy in atmosphere substantially free from moisture and oxygen, reheating the cooled alloy to a temperature lower than said super-anneal ing temperature and rapidly cooling the thus reheated alloy, whereby the permeability of the allov is greatly increased.

12. The process of heat treating magnetic prises rolling a magnetic iron-nickel alloy to, form .a sheet, treating said sheets to clean the same and remove grease therefrom, coating the cleaned sheets with a refractory material ofthe group comprising magnesia and lime, said refractory material being free from sulfur, arranging the thus-coatedsheets in a stack, subjecting the stack to an initial super-annealing treatment for about several hours at a temperature of about 2000 F., slowly cooling the super-annealed alloy in a reducing atmosphere of dried gases, re-heating the cooled alloy to a temperature of about 1160 F. for a relatively short time and then rapidly cooling the thus reheated alloy, whereby the magnetic permeability of the alloy is greatly increased.

13. The process of heat treating magnetic alloys of the nickel-iron type which comprises subjecting such alloys -to an initial super-annealing treatment in a reducing atmosphere containing hydrogen substantially free from moisture, slowly cooling the super-annealed alloys in a reduced atmosphere containing hydrogen substantially free from moisture, reheating the thus cooled alloys to a lower temperature than the superannealing temperature and rapidly cooling the thus reheated alloys whereby the permeability of the alloys is greatly increased.

a hydrogen the nickel-iron type, which com- .In testimony whereof, I have hereunto set 1 my hand.

CLARENCE GEORGE BIEBER.

consisting of about 75% I