US1821493A - Annealing - Google Patents

Description

V. B. BROWNE Sept. 1, 1931.

ANNEALING 2 Sheets-Shea?l 1 Original Filed May 28, 1927 2 Sheets-Sheet V. B. BROWNE Sept. 1, 1931.

ANNEALING original Filed Maf' 28, 192'? FIG Z.

Vm/07M wwwa@ atentecl Sept. l, 1931 I PATENT OFFICE D'VERE B. BROWNE, 0F BRAC'KENRIDGE, PENNSYLVANIA 'ANNEALING Original application led May 2.8, 1927, nSerial No. 194,927. Divided and this application led September 26,

1929. Serial No. 395,224.

This invention relates to the manufacture of magnetic alloy sheets and more particularly to the annealing of relatively thin sheets of silicon iron or so called silicon steel for use in the manufacture of electrical apparatus, and this application is a division of my 'copending application Serial No. 194,927, led May 28, 1927.`

-In the annealing of light gauge silicon iron or so called zsteelsheets for use in the manufacture of electrical appara-tus, it has been shown that if the correct temperature is obtained andthe time of annealing is sufficient, better results are obtained by annealingA the sheets singly than in "stacks as in standard box annealing operation.

Obviously the best results, therefore, should be obtained by annealing in a continuous furnace in which the sheets are charged at one end of the' furnace and passed through a correct temperature zone and at a rate of speed such as to give the necessary time element to the annealing. Such a furnace canv be made suiliciently long vto permit a cooling zone vthrough which sheets-pass after they are annealedso that Y neale'd in any of the continuous furnaces withfwhich I am familiar become warped or buckled and unsuitable for use in the manufacture of electrical apparatus. 'Flatness is most important in sheets for use in the manufactureof electrical apparatus.

It has been found that in orderto obtain magnetic alloy sheetsV ofthe highest qual-- ity it is necessary during the annealing thereof to lprevent the gases given off from the sheets during the anneal from being reabsorbed. l

An object Vof this invention is -to provide an apparatus for the annealing of magnetic are subjected to flattening strains of suftional view, partly broken away, through the "can be employed. The sheets tobe annealed are passed through this .annealing chamber,

alloy sheets by means of which thel-sheets are not only maintained lat during the anneal but are delivered from the anneal fiat and with a minimum amount of occluded gases.

A further object ofthis invention is to provide an apparatus for the annealing of magnetic alloy sheets in whichthe sheets during the anneal and subsequent cooling ficient intensi-ty to overcomeV the' distorting 60 strains produced-in the Sheets during -rolling and during cooling after annealing,

A still further objectl of this invention is to provide an apparatus for the annealing of magnetic alloy sheets in which thorough Ventilation of the sheets during annealing and subsequent cooling is obtained whereby the gases given off from the sheets during `annealing are rapidly carried out of contact with the sheets. Y

These and other objects which will be apparent to those skilled in this particular art are accomplished by means 'of the apparatus illustrated inthe accompanying drawings and described in detailin the specification. In the" drawings, Figure l is a perspective partially broken-away view of an annealing apparatus embodying one form of this invention, andA Fig. 2 is a transverse sec- 80 apparatus illustrated in Fig. 1. n In carrying out this invention, an annealing chamber of any desired type orV form or under some circumstances may merely be .positioned therein,`where they Will be sub-v jected to the annealing temperature'. Each` sheet is so supported as to be separated from every other sheet in the chamber so that perfect ventilation may be obtained around each of the individual sheets. If desired, the sheets may be in groups of'two or more, as illustrated. In order r'to remove the buckles due to rolling and tor prevent any distortion of the sheets during cooling after annealing each sheet is subjected ytoan ex ter'nally applied strain which places the sheet under-such tension -as -to insure its hold them in flattened condition until their l temperature is lowered to the necessary point.

'Ihe particular form of apparatus illustrated in the accompanying drawings, in-

cludes a furnace formed from a plurality of similar sections 5 having recesses G so formed in the inner walls thereof that when two sections are positioned opposite to each other the oppositely positioned recesses cooperate to provide an annealing chamber 7 having slots 8 and 9 extending through the top and bottom, respectively, of the furnace, and communicating with the annealing chamber. In the form shown for illustration the furnace is heated by electric resistance elements 10 but it will be apparent that any type of heater can be employed. It will also be apparent that an annealing chamber and furnace of any desired length can be provided by associating together a sufficient number of individual furnace sections.

Mechanism is provided for passing the sheets to be annealed through the annealing chamber. As illustrated, this mechanism includes a track 11 which extends longitudinally above the furnace in line with the slot'8 communicating with the upper end of the combustion chamber. Trolleys 12 are supported upon the track by rollers 13 and each trolley has a hanger 14 secured thereto and extending downwardly below the top of the annealing chamber. Each hanger 14 has a plurality of upwardly inclined prongs 15. on each side thereof for the purpose of supporting a pair of sheets 16 to be annealed.

In order to prevent distortion of the sheets during the annealing operation they are subjected to'stretching or tension of such intensity asto flatten the sheets as they are softened during annealing and to hold them fiat during their passage through the annealing and cooling zone of the chamber. As illustrated, this mechanism includes a track 17 which is parallel to the track 11 and is positioned in line with and below the channel or slot 9 communicating with the bottom of the annealing chamber. A hanger 18 having sheet engaging lprongs 19 is secured to the lower edges of the sheets 16 and aninverted trolley 20 having a roller 21 engaging the bottom of the track 17 is connected to the inverted hanger 18 by a suitable connection preferably .including a The springs 22 are of` helical spring 22. such strength that the sheets stretched thereassises by will be flattened when soft and will be held taut and rigid during the entire annealing and cooling operation. In this way the buckles and other unevennesses due 'to rolling are obliterated and the buckling during cooling is overcome. rIhe sheets can be moved through the annealing chamber at the desired rate of speed by shifting the trolleys along the associated tracks.

It will be apparent that the sheets during annealing are perfectly ventilated, thus permitting the free escape of occluded gases.v

rlhis results in finished sheets having extremely low magnetic losses. Absolute Hatness of the finished sheets is insured by positively maintaining the sheets taut and rigid during the entire annealing and cooling operation. Gbviously, the sheets can be passed through the furnace in groups of two, as illustrated, or theyr may be pasted singly therethrough.

That I claim as new and desire to secure by Letters Patent is:

1. An annealing furnace formed of two oppositely positioned sections provided with recesses in their inner faces cooperating to form an annealing'chamber, said sections being spaced so as to provide slots extending through the roof and floor of said furnace and communicating with said chamber, a track associated with the slot in said roof and a trolley movable along said track and extending into said chamber for supporting a sheet to be annealed, a second track positioned beneath the slot in said iioor and mechanism movable along said second track and engaging said sheet for applying a stretching force thereto.

2. AnYa-nnealing furnace formed of two oppositely positioned sections provided with recesses in their inner faces cooperating to form an annealing chamber, said sections being spaced so as to provide slots extending through the roof and floor of said furnace and communicating with said chamber, means associated with the slot in said roof for supporting a sheet to be annealed, and means associated with the slot in the floor to apply a stretching force to said sheet.

3. An annealing furnace formed of two oppositely positioned sect-ions provided with recesses in their inner faces cooperating 'to form an annealing chamber, said sections being spaced so as to provide slots extending through the roof and floor of said furnace and` communicating with said chamber, means associated with each slot to support a sheet to be annealed in the furnace and apply a stretching force tothe opposite end of saidsheet.

f 4. An annealing furnace formed of two oppositely positioned sejctions provided with recesses in'their inner faces cooperating to form an annealing chamber, said sections being spaced so as to provide slots extending means for engaging the top of the sheet.

5. An annealing furnace forlned of two oppositely positioned sections provided with recesses in their inner faces cooperating to form an annealing chamber, said sections being spaced so as toprovide slots extending through the roof and ioor of said furnace and colnmunicating with said chamber, means associated with the slot in said roof for supporting a sheet to be annealed, and means associated with the slot in the floor to apply a stretching force .-to said sheet, saidl second means including a track, a trolley having a roller engaging said track from below and a` hanger extending into said chamber for engaging the bottom of the sheet, and a spring between said trolley and hanger.

6. An annealing furnace formed of two oppositely positioned sections provided with recesses in their inner faces cooperating to form an annealing chamber, said sections being spaced so as to provide slots extending through the roof and floor of said fur- .nace and communicating with said chamber,

means associated with the slot in said roof for supporting a sheet to be annealed, and means associated with the slot in the floor to apply a stretching force to said sheet, said first means including a track, a trolley having a roller engaging on said track and a hanger connected to said trolley4 and extending into said chamber provided with means for engaging the top .of the sheet, said second means including aL track, a trolley having a roller engaging said track from below and a hanger extending into said chamber for engaging the bottom ofthe sheet, and a spring between said trolley and hanger.

7. An annealing furnace formed of two oppositely positioned sections provided with recesses in their inner faces cooperating to form an annealing chamber, said sections being spaced so as to provide slots extending through the roof and floor of said furnace and communicating with said chamber, means associated with the slot in said roof for supporting a sheet to be annealed, and means associated with the slot in the Hoor to apply a stretching force to said recesses in their inner faces cooperating to form an annealing chamber, said sections being spaced so as to provide slots-extending through the roof and floor of said furnace and communicating with said chamber, means associated 'with the slot in said roof for supporting a sheet to be annealed, and means associated with the slot in the fioor to apply a stretching force to said sheet, said chamber being of Variable length depending upon the number of oppositely associated sections assembled end to end to give the desired length.

In testimony whereof, I have hereunto subscribed my name this 14th day of September, 1928.

VERE B. BROVNE.

sheet,-sai d chamber having internal heating means.

8. An annealing furnace formed of two oppositcly posltloncd ser( lons provided with

Images