US1249056A - Apparatus for heat treatment of steel. - Google Patents

Description

T. J. FAY.

APPARATUS FOR HEAT TREATMENT 0F STEEL.

APPLICATION FILED JULY 9. I9I4.

Patented. Dec. 4,1917.

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APPARATUS FOR HEAT TREATMENT 0F STEEL.

APPLICATION FI'LED JULY 9,19l4.

Patented Dec. 4,1917.

2 SHEETS-SHEET 2 n @NU .20 may be heated for the-ordinary forging urlava THOMAS J'. TAY, OF BROOKLYN, NEW`YORK, ASSIGNOR. BY MESNE ASSIGNMENTS, TO THE STANDARD PARTS COMPANY, OF CLEVELAND, OHIO,'A CORPORATION. 0F OHIO.

APPARATUS FOR HEAT TREATMENT OF STEEL.

Specification of Letters Patent.

rammed nee.. a, tei t.

To all 'whom 'it may concern.'

Be it known that I, THoMAsJ. FAY, a citizen -of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented a certain new and usefull Improvement in Apparatus for Heat Treatment of Steel of which the following isa full, clear', and exact description, reference being had to the accompanying drawings. This invention relates to an apparatus for the heat treatment of steel and more especially of articles such as plates that are used inthe construction of springs. The apparatus disclosed herein comprises generally a furnace (or a plurality of furnaces) wherein the plates-in the case of spring manufacturlng-after having. been cut to length and having the center holes punched. thereinoperations which precede the heating o the plates for cambering and harden1ng purposes; the apparatus comprises also"a construction and arrangement whereby the assembled springs may be subjected to a drawing-'or annealing temperature (preferably by the waste .gases from the aforesaid furnace .or furnaces)'and whereby this annealing or Adrawing may be accomplished simultaneously with the qoatingof enamel applied to the springs. In carrying outfmy invention, means are provided whereby the temperature will vary from end -to end of each plate and whereby the temperature to which each plate B5 subjected will vary with the amount of its lmmersion in -a heated ,bath-preferably of sand. Itis a further objectof the invention o provide a furvl'lacewherein a bed of granular refractory material constitutes a bath 40 into which the article to be heated may be inserted and wherein the heat is so distrib,- uted' throughout the furnace and; applied to the bath as not to` cake the. refractory material and thereby. interfere with the-introduction of the.articlesthereinta With the foregoing objects in view the invention may be defined further and gener ally as consisting of the combinations of elementsembodied 1n the claims vhereto annexed E0 -and illustrated in the. drawings forming part hereof, wherein Figure 1 represents a'vertical sectional view corresponding to the line 1.-] of Fig.-3 andzlooking in the direction of the arrows; Fig. 2 represents va vertical sectional t5 view corresponding to the line-2 2 of Fig.

Awall 3 is provided with an viiuid-for instance,

l i l and looking in the direction of the arrows;

and Fig. 3 a View, partly in elevation and partly in section,'.the section through the right hand furnace corresponding to the line In the embodiment of my invention illus' trated herein, two quadruple furnaces are shownthe outlet fiues whereof communicate with a common discharge duct, located therebeneath, and discharging into a llue extendf ing beneath a tunnel. For convenience;` of description, it ma be vas sumed that each quadruple furnace 1s a unitand, for economy of construction and eiiicienc in operation, it has been foundto .be desira le to construct the furnacesjin the manner illustrated and described herein. i

lfdenotes thev top,'2 the side walls, and 3 the end Walls ofone of the' furnaces referred to, said furnaces being articularly well adapted for heating the endPs of plates to per-v mit of the various forging operations relimina'ry to cambering and hardening. liach opening 4, near the bottom thereof, communicating with the combustion chamber 5, said opening serving v for the introduction of the combustible gas or oil mingled with air. A suitable burner, indicated at 6, is shown as projecting4 into each opening 4.

Each combustion chamber is' preferably pro;

rial.4 With this arrangement, `spaces 11 are provided between each slab 10 and the sub- ]acent arch, each of which spaces is placed in communication with its respective 4com- 100 bustion chamber through a suitable opening 9a in each arch, said opening '(where one opening is em loyed ineach space) being located about alf way between a central opening is employed in each space) bein loedge thereof. Extending upwardly rom each combustion chamber is a air of ues 12, said dues being located in the ongitudinal wall 13 which extends the length 'of each unit and divides the same into two pairs of llt furnaces. Each of the ilues 12 communicates at its upper end with a pair of downwardly andy laterally extending lues 14, said iues discharging the products of combustion into the' upper portions of the two furnaces 15 (the details of which will be described hereinafter) located above each combustion chamber and located on opposite sides of the wall 13.

The products of combustion, after circulating throughout the heating furnaces 15, above the sand bath therein, are discharged from the ends thereof. One of the discharge iues of each furnace 15 (see Fig. 2) is provided in the wall'3, as indicated-at 16, the products being discharged from a point near the roof of the furnace. The discharge from the opposite end of the furnace is through an downwardly inclined passageway 17 in the wall 13. A similarly arranged pas# sageway 17 is provided for the adjacent furnace on the opposite side of the wall 13,`and this pair of passageways merge into a common downwardly lnclined flue 18, which flue is itself inclined downwardly toward the central portion of the quadruple furnace,

where it merges with a similar flue 18 which conducts the gases from like points in the walls of the other adjacent pair offurnaces. The flues 18 vmerge into a common centrally located down-flue 19 which communicates at its lower end with a transverse flue 20 located' beneath the quadruple furnace. Each furnace 15 is provided with a flue 16 in the end wall 3, there being four such lues for the quadruple furnace herein described..

flues 16 in each end wall 3,

However, the

downwardly a sufficient disafter extending tance to clear the burner opening 4:, mergev into a common centrally arranged downflue 21, the flues 21 also discharging into the common discharge Hue 2O.`

As will be evident from an inspectionlof Fig. 3, the two units, comprising eight furnaces, discharge 'their waste vgases into the flue 20, said ueconducting the gases into a cross lue`22 the topwhereof is covered by a plate 23 of cast iron or similar heat-radiating material. The top of this plate is provided: with a trackway 24, and the space above thefplate is inclosed to provide a tunnel 25, the side and top walls 26 whereof are lined with non-heat-conductin material 27, the ends of the tunnel being c osed by suittble doors 28, similarly lined to'prevent heat oss.

Each furnace 15 is located above a slab 10. It will be noted (see particularly Fig. 1) that the lower part of each unit containing the combustion chambers 5 is of considerably reater width than .the part thereabove. he outer lateral ends of the slabs 10 are at the bottoms of inwardly inclined surfaces 29 provided at the upper ends of the walls 2f. These slabs, the inclined surfaces 29 of faience the walls 2i1 and the central wall 13 provide inclosures and supports for beds of granular refractory material 30, such as sand. Each furnace is provided with an opening 31 adapted to be closed by a sliding door 32 of suitable refractory non-heat-conductin material, which door is preferably provide with a beveled end 33, whereby it may enter the sand to a suilicient distance to form a seal therewith against theV escape of he products of combustion in the furnace 15. These doors are conveniently guided between channel-iron guideways 34.

. The furnaces shown herein are es ecially designed for heating the ends o metal plates, such as enter into the construction of, springs, prior to the various forging operations, two of these plates being indicated at 35 and 36 (see Figi 1). One of these plates is shown as resting on top of its wall 2a and has its inner end lnserted into the sand beneath, and a short distance within, the bottom of the door 32. The other plate is shown as inserted to the maximumextent into the sand bed beneath the door 32.

It will be observed that a part only of each bath or bed of sand is subjected to the action of lthe heat within a furnace 15; in other words, the. sand bath is heated at one end and is open tothe atmosphere at the other end. It follows, therefore, that the sand mass for each furnace varies in temperature from a maximum at the inner end (adjacent to the wall 13) to a minimum at the outer end (above the top of the inner portion of the wall 2n) It also follewsethat the temperature of any plate immersed in cent furnaces 15. The inner end of this plate will be yheated thereb" to the maximum temperature ossible, but t e temperature in the late wil decrease from the inner towar the outer end thereof. The plate 35, which is shown as inserted about half the distance between the door 32 and thewall 13, will be heated to a correspondingly less degree, not only as to its inner, or maximumheated, end, but to a less degree throughout its entire length. lt is proposed to use with each furnace a pyrometer inserted in the sand adjacent to the inner wall thereof-the central wall of the furnace assembly.

ln the operation of a furnace constructed in accordance with my invention, the plates, being inserted into the furnace through the in the. sand.

' the subsequent treatment of vidual plates for the exteriorly exposed surfaces of sand and beneath the doors 32 (which seal the exterior portion of the sand from the portion within the combustion chamber) are always sealed from the products of combustion, whereby the overheating ofthe steel and the formation of scale are absolutely prevented. Furthermore, through this construction, there will be no necesslty for the operator to open and close doors-thereby realizing a great saving in time.

It is intended to use the products of combustion discharged from the furnaces 15 for the plates, and more especially for the purpose of drawing or annealing the springs in mass or assembled condition. For this purpose, the products are `discharged into the transversely extending ue 22 and impart their heat to the plate 23. The heat radiated from the plate 23 will raise the temperature within the tunnel 25 to a sufficient degree to anneal the assembled springs and vdo so. without subjecting the springs A(and the plates thereof) to the direct action of the heating gases. The annealing of the springs in bulk will give superior results to annealing the indifollowin reasons The-longwor main plate shoul ybe a little softer than the other plates; by annealing in mass, this result is secured because of the fact that -the long plate is on the outside of the assembled plate and hence is subjected to a greater heating effect. .The `ends of the short plates should also be alittle softerl since these ends .are freely exposed while the bodies are protected throu hout the major portion of their length by teir contact wlth adjacent plates. The assembled springs are indicated at 35 on the truck 36.

` In treating the springs in the tunnel 25it is-contemplated that, before sub'ecting them to the annealing operation, t ey will be coated with enameling material. perature within the tunnel will serve,not only toanneal the springs, but to'bake the enamel thereon and this operation is secured through the use vof the waste gases from the furnaces 15-a very important feature of my invention. The enamel with which the springs are coated serves to protect the steel during the annealing process and prevents any change in the percentage of the carbon constituent thereof or infthe carbon saturation. 'lhe apparatus disclosed herein is capable of and intended to 'be used in conjunction with that disclosed in my application No. 841,982, filed June 1, 1914 and .which coperates-therewith for the production of springs wherein the heating necessary for declescence and the subsequent annealing is applied without subectin the plates at any time-to the lickmg o the flames or to the direct action of the heat.

lprimarily for the treatment than the other parts; this result is securedcommunication with the co At' no time during the treatment are `the plates subjected te the direct action of the heat, thereby protecting. them against-molecular shocks. After the tempering heating, (which may be 'administered through 70 the style of the furnace disclosed in my prior application) the plates will be chambered through suitable mechanism, chilled, assembled, and annealed in assembled form as shown herein, the heat being applied to the furnace throughout the production of the springs by the indirect method disclosed herein.

While' the construction and process illustrated and described herein are designed of plates which enter into the production of springs, it will be evident that the process and apparatus are capable ofv more general application. For instance, the action of the furnaces in the .progressive and proportional heating of the articles inserted therein will be the Same with respect to any elongated articles capable of being thrust into the sand bath. It is obvious that rods areas capable of treatment in the furnaces shown herein as are plates. Hence, while, for convenience of description, specific reference is made to plates in the 'specification and claims hereof, I do not intend thereby to be limited in the uses of my invention nor to be limited as to the specific articles treated. thereby.

Having thus described my invention,I what I claim is l. In an apparatus of the character described, the combination, with a furnace chamber having means for supporting articles to be subjected to heat treatment, of means for supplying gases of combustion to said chamber to heat such articles therein, a tunnel the bottom wall whereof consists of a plate of radiating material, said tunnel having a track'therein and provided withdoors and walls provided with non-heat-conduct- 1.10 ing material, vand, a flue beneath such heat radiating plate and receiving the gases of combustion from said chamber.

- 2. Ina furnace, the combination of afcombustion chamber and a -heating chamber 11a the'reabove, a slab interposed between said chambers, an arch for the combustion chamber beneath said slab, there being spaces provided between the slab and the lateral portions of the arch, said sltces being in 12o m ustion chamber, and vmeans for delivering gases of combustion from the first chamber to the second chamber at a point above said slab.

3. In a'furnace, the kombination of a combustion chamber, a heating chamber thereabove, a slab forming the bottom of the heating chamber and -1nterposed between the same and the combustion chamber, an arch forthe combustion Ychamber supporting the 180 `and a slab at its central portion and provided with openings placing the spaces beneath the lateral portions of the arch and the slab thereabove in communication with the combustion chamber, and means for delivering gases of combustion from the first-mentioned chamber into said heating chamber at a point above said slab.

4. In a furnace, ythe combination of a heating chamber, a bath of refractory granular material within said chamber and extending outside the same, and a gravity door for said chamber adapted to'rest -upon the granular material and seal the external portion thereof from the portion within the chamber.

5. In a furnace the combination of a heating chamber, a bath of refractory granular material within said chamber and extending outside the same, and means for sealing the external portion of the mass of Ibnaterial from the portion within the cham- 6. In a furnace, the combination of a heating chamber, a slab forming the bottom of said heating chamber and extending outside of said chamber, there being a bath of granular refractory material on said slab, vertically movable door carried by said furnace and having its lower end beveled whereby it is adapted to rest upon said bath and seal the external'portion thereof from the portion within said chamber.

'7. In a furnace, the combination of a heating chamber, a bath located partly within and partl without said chamber, and means for sea ing the surface portion of the external part of said bath from the part within said chamber.

8. The combination, .with a plurality of heating-chambers,l of a plurality of combustion chambers located beneath said heating chambers, there being flues conducting gases of combustion from the last mentioned chambers to the first mentioned chambers, a downwardly descending flue leading from each of the heating chambers, and a flue beneath the combustion chamber into which the first mentioned fines discharge.

9. In a furnace, the combination of a heatcombustion chambers with istante ing chamber, a combustion chamber located beneath said heating chamber, there being one or more iues conducting gases of combustion from the combustion-chamber to the heating chamber, a bath of granular refractory material in the heating chamber beneath the iue connection or connections, and one or more outlet flues leading from the heating chamber and communicating therewith above said bath.

10. The combination, with a plurality of heating chambers and a plurality of combustion chambers therebeneath, of a pair of lues conducting gases of combustion from each combustion chamber to each heating chamber thereabove, each `of the heating chambers being provided with a pair of outlet openings arranged in opposed walls thereof, downwardly extending iues communicating with said outlets, a flue beneath the which the last mentioned flues communicate, and a heating space or 'chamber above and in operative relation to the last mentioned flue.

11. In a furnaceinstallation, the combination of two pairs of combustion chambers and two pairs of heating chambers there-l above, the pairs of chambers being separated by an intermediate wall and each pair having a common outer wall, flues conducting gases of combustion from the combustion chambers into the heating chambers thereabove, each heating chamber having an outlet in the end wall and an outlet in the intermediate wallfthe outlets of all four heating chambers in the intermediate wall communicating with a single downwardly extending flue and the outlets from each pair of heating chambers in an end wall communicating with a common fiue in said wall, there being a flue beneath the combustion chambers with which the downwardly directed flues communicate.

In testimony whereof, I hereunto affix my signature in the presence of two witnesses.

THOMAS J. FAY.

Witnesses:

P. A. CoNNoLLY, W. E. PERRINE.

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