US2387835A

US2387835A - Method of and apparatus for heattreating metal bodies

Info

Publication number: US2387835A
Application number: US196634A
Authority: US
Inventors: Roger O Day; Britton L Gordon
Original assignee: Linde Air Products Co
Current assignee: Linde Air Products Co
Priority date: 1938-03-18
Filing date: 1938-03-18
Publication date: 1945-10-30
Anticipated expiration: 1962-10-30

Description

Oct. 30, 1945. R. 0. DAY ETAL METHOD OF AND APPARATUS FOR HE AT TREATING METAL BODIES 1938 4 Sheets-Sheet 1 Filed March 18,

.HMHHW" ITI\ mlllll INVENTORS Q OGER 0. DAY

BRITTON LGQRDON Z ATTORNEY Oct. 30, 1945. R. 0. DAY ETI'AL 2,387,835

METHOD OF AND APPARATUS FUR HEAT TREATING METAL BODIES 4 sheets-sheet 2 7 Filed March 18, 1938 FIG.7.

T 1 w M m w .m mi T10. O o 6 m G Q bfihv RW EY G A! i. WM v F m ,m E 0 8 V 4 .E. A fi L. 6 w M 3 m 5. 2 7 Il 1 5 n I z I 00 t f 1. a a v F 6 0. M 8 0 9 H C 2 T 6 5 A \QL 5 0 w a a w Oct. 30, 1945. R. 0. DAY ET AL 4 METHOD OF AND APPARATUS FOR HEAT TREATING METAL BODIES Filed March 18, 1938 4 Sheets-Sheet 5 FIGS.

INVENTORS" ROGER O. DAY

ATTORNEY BRITTO L. GORDON Get. 30, 1945. R. 0. DAY T L 2,387,835

METHOD OF AND APPARATUS FOR HEAT TREATING METAL BODIES Filed March 18, 1938 4 Sheets-Sheet 4 l ll FIG. 10. ll/

INVENTORS ROGER 0. DAY Q BRITTON L.GORDON ATTORNEY i Patented Oct. 30, 1945' NiTED STATES PATENT OFFICE- METHOD OF AND APPARATUS FOR HEAT;

TREATING METAL BODIES Roger 0. Day, Westfleld, and Britton L. Gordon, Montclair, N. 3., assignors to The Linde Air Products Company, a corporation of Qliio Application March 18, 1938, Serial No. 196,634,

12 Claims. ((1148-2155) g This invention relates to the heat treatment of metal bodies, and to the hardening of surface portions thereof by the application of high temperature heat, preferably followed by the application of a suitable cooling medium. This invention also relates to a method of heat treating, by flame hardening, surfaces of revolution of metal bodies, such. as the interior or exterior surfaces of tubes, cylinders, shafts, or the like,.

combustion of a mixture ofpxygen and acetylene,

or similar gases. are applied to a surface in order to heat the metal toa desired depth and to a temperature at or above the critical range, after whiclr'the heated metal is cooled rapidly to proprinciplesof this invention may be applied to instances in which other sources ,of high temperature heat are utilized.

. It is not only desirable but also necessary in ,most applications of surface'or flame hardening to produce a uniform hardness, both laterally or circumferentially and also longitudinally of a surfaceor portion thereof. A shaft or rod for moving the piston-of a reciprocating compressor, for instance, must have a uniform hardness longitudinally, or unequal wear will occur which will cause the shaft not only to rock in its bearings, but also cause leakage past the packing; and

the 'rod also must have a uniform clrcumferential hardness, or unequal wear-will cause packv ing leaks at various circumferential points. Similarly, a tubular liner for the cylinder of. a pump or compressor, for instance, must be provided with an lnnersurface having a uniform duce a hardened structure. In some instances,

the entire surface portion is heated and then cooled, while in other/ instances successive portions are heated and cooled in a progressive manner. greatest applicability to the latter or progressive method.

. Furthermore, a variety of cooling methods have The principles of this invention have their been emp oyed. Air hardening steel. for in-- stance, will harden upon natural cooling, and the surface portion to be hardenedneed'only be heatedzwhile the usual rail steel normally requires only the application of an air quench to produce sufllcient cooling for hardening. However. the reat maiority of metals reduire the application of a water or similar quench to effect the sudden or rapid cooling necessary to produce the desired hardness. and this invention. will -be explained with reference to such cooling. although it will be understood that other methods of cooling may be em loyed where the-nature of the metal or other co siderations indicate that such other methods are desirable. i

In addition. beating has been accom lished by means other than hi h tem erature beating flames. such as by electric arcs. and while this invention is to be explained with reference to heating flames, it will be understood that the hardness both circumferentially and longitudinally, or unequal wear from the piston travelling thereover will result in grooves or depressions at which the rings ordinarily employed will be unable to prevent leakage, It will be obvious that a uniform hardness is also desirable'over the surfacesof gear teeth, rolls, rails; tracks, and other types of metal bodies.

Previous attempts to produce a uniform hardness over a surface, or surface portion, of various types of metal bodies have not always been suc- For instance, it has been proposed-to cessful. harden the inner surface of a cylinder or the outer surface of a cylinder or shaft by passing, in a helical path over'the surface, a high temperature source of heat, such as 'an electric arc, directly followed by a quenching jet, but .such a procedure results in a helical path of greater hardness and in interspacedhelical path of lesser hardness due to an annealing eflect on portions already hardened through heating adjacent surface portions. It has also been proposed to harden the inner surface of hollow bodies. such as automobile cylinders, by moving the cylinder at a constant rate down past a star-shaped. burner andinto a body of quenching fluid. but-such a procedure does not result in auniform circumferential hardness due to the unequal circumferential'distribution of heat from azstar-shaped burner. nor a uniform longitudinal hardness due to heating of the quenching fluid within the bore of the cylinder. which becomes isolated from'the remainder of the liquid as the cylyinder passes into the body of quenching tluid, Furthermore, the tendency for bubbles of steam to collect on a heated surface in a body of cooling 'fluid such as water usually results in spots of unequal hardness at various points on the surface. In neither of these instances is a uniform hardness produced over the entire surface, either circumferentially uniformly in order to produce a uniform hard-.

ness and a hardened case of uniform thickness thereover; to provide such a method in which outer or inner surfaces of cylindrical objects such as tubes, shafts, rolls and the like, as well as objects having plane, curvilinear, or irregular surfaces, are hardened uniformly; to provide such a method in which a relative movement. between a heating and cooling means and thesurface to "be treated, in more than one direction is utilized to effect a more uniform heating and cooling of the surface; to provide such a method in which the hardening operation may beaccurately controlled; to provide apparatus particularly adapted to carry out the method of this invention; to provide such apparatus which is adapted to hold-the object accurately in position and at the same time permit expansion during heating; to provide such apparatus in which the-objectto be treated is held in a vertical position; to provide such apparatus in which the object to be treated is ro tated;.and to provide such apparatus in which the rate of relative movement between the heating and cooling means and the surface to be treated maybe varied.

Other objects and novel features of this invention will become apparent from the following de-, scription and accompanying drawings, in which:

i Fig.- 1' is a front elevation of v pp atus constructed in accordance with this invention and particularly adapted for hardening an inner surface of a hollow metal body; I

Figs.,2 and 3 are enlarged horizontal sectional views taken on the lines 2--2 and 33 of Fig. 1;

. Fig. 4 is a side elevation of the apparatus of Fig. 1, partially in section taken on the line 4-4 of Fig. 1 and with certain parts in a different relative position;

form high temperature, and the heated zones are cooled successively or simultaneously in order to harden the same. Each successive zone is raised to the same uniform high temperature'by effecting a relative longitudinal movement between the source of heat and the surface which may vary in its rate. In accordance therewith, the relative rate of longitudinal movement is retarded during the time the initial zone or zones are being heated to cause the first or initial zone to be heated to the same temperature and depth as subsequent zones. That is, a relative movement between the surface and a. source of high. temperature heat is first effected at a selected rate which is retarded or lower than the normal rate, and the relative movement at this selected rate is continued while the initial zone of the surface is being -heated. When the source has passed beyond the initial zone and the latter has been heated to the predetermined desired temperature, the relative movement is accelerated to the normal rate, higher than the selected or initial rate. Since the conduction of .heat from a zone being heated to an adjacent, or second zone, subsequently to be heated, effects acertain amount of preheating of the secondzone, thus reducing the amountof heat necessary to raise the second zone to the desired temperature, a retarded initial rate of relative longitudinal movement will compensate for the lack of such preheating of the first or initial ofthe surface will tend to causethe end to be overheated, and the rate of relative longitudinal movement is therefore accelerated in order to avoid such overheating.

' Furthermore, a metal body often includes portions of reduced or increased cross-sectional area which will tend to cause alesser or greater in accordance with the tendency for the body itself to conduct heat away from the zone being heated. Specifically, the relative rate of longi tudinal movement is accelerated in heating a zone adjacent. a portion of reduced cross-sectional area, such as may be occasioned by threads or other configurations, in order to prevent such zones from being overheated due to the tend- Fig. 5 is a. top'view on an enlarged scale of the heating andquenching head of the apparatus of Figs. 1 and 4;

Fig. 6 is an enlarged horizontal sectional view of the heating and'quenchinghead taken on the line 6-6'-of Fig. 4;"

' Fig. 'l is a partial vertical sectional view taken on the line |l of Fig; 6;

Fig. 8 is a front elevation of apparatus similar to that of Fig. 1, but particularly adapted. for hardening an outer surface of a metal body;

Fig. 9-is a horizontal sectional view taken alon the line 99 of Fig. 8;

Fig. 10 Ban enlarged partial'vertical sectional view taken along the line iii-ill of Fig. 9; and

Fig. 11 is a partial horizontal sectional view, similar to Fig. 9, of a modified form of the apparatus of Figs. 8-10.

In accordance with this invention, a'surface of a metal bodylis hardened by progressively applying high temperature heat to successive lateral zones or portions thereof in such a manner that ency fora lesser amount of heat to be conducted therefrom; and the relative rate of longitudinal movement is retarded in heating zones adjacent a portion of the body having an increased crosssectional area, such as may be occasioned by flanges, lips, or shoulders, ,in order to compensate for the greater amount of heat conductedaway from the zone being heated. It is of course understood that the configuration which causes theincreased or decreased cross-sectional area will usually, but not always, be that of'a surface which is not the one being hardened, since the hardening of such configurations normally requires special treatment.

In addition, themetal body is preferably so positioned that the surface to be treated is disposed substantially vertically, with heat being V the successive zones are heated to the sanie uni- 7s initially applied at the lower end of the surface portion to be.hardened so that the normally rising heat will have'no effect upon previously heated zones butwill tend to. preheat unheated zones, and quenching fluid, when utilized, will flow downwardly along the treated zonesoi' the surface and will also have no tendency to interfere with the application of the heating flames or other heating medium.

- The principles of. this invention Just set forth surface of revolution of a metal bodyis hardened by applying high temperature heat from a suitable source to successive circumferential zones,

thereof, and effecting a relative rotational movement as well as a relative longitudinal movement between the surface to be hardened and the source of heat. A varying rate of relative longitudinal movement, as previously described, may be utilized in hardening surfaces of revolution, and in case a quenching fluid is directed onto the a heated zones in order to harden the same, the

quenching fluid is preferably applied closely fob lowing the application of heat and with the same rate of relative longitudinal movement.

posite threads I I, which cause a reduction in the cross-sectionalarea of the liner wall, is being heated; and to be further accelerated as the end 0f the cylinderis reached in case the end of the surface portion to be hardened coincides therewith. Other and more specific features of this apparatus and its operation, as illustrated also in Figs, 2-7, will become apparent from a later more detailed description. I

A somewhat similar apparatus, also constructed inaccordance with this invention, but more particularly adapted for hardening an outer surface such as that of a cylinder or roll, may comprise in general a carriage C, as in Fig. 8, adapted to move upwardly and downwardly along a vertical framework F, as before, but which instead carries heating and quenching means H adapted to heat and cool successive circumferential zones of a workpiece W', such as a roll. The roll W is supported at its lower end by a rotating center S, and held in alignment at its upper end by a weight-loaded and vertically movable center S which permits longitudinal expansion during treatment. The carriage is moved upwardly and downwardly by a variable speed motor D acting through suitable mechanism, and the center S 'is rotated by a substantially constant speed motor M, also acting through suitable mechanism.

In hardening inner surfaces of hollow bodies such as tubes or cylinders, the body is prefers ably moved downwardly over the heating and cooling means; while in hardening outer surfaces of bodies such as shafts, the heating and cooling means are preferably moved upwardly along the surface. These relative movements are not obligatory, but it has been found that they simplify the apparatus necessary to carry out the method of this invention.

Other novel features of this invention, such as the provision of a means for effectively supply-- ing air, or other oxygen containing gas, to insure adequate secondary combustion of the heating flames in the treatment of an inner surface of a hollow or tubular-body, will become apparent from a following'description of apparatus particularly adapted to carry out the method of this invention.

Apparatusconstructed in accordance with this invention and particularly adapted for hardening the inner surface of a hollow metal body may comprise in general a carriage C, as in Fig. 1, which is adapted to move upwardly and downwardly along-a vertical framework F and upon which a workpiece W, such as a linerfor a pump, is rotatably mounted. The liner W is rotated through suitable mechanism by a motor M mounted upon the carriage C, and the carriage is moved upwardly and downwardly by a motor A acting through suitable mechanism which includes a variable speed drive V. In order to harden the inner surface thereof, the liner W is passed downwardly over a heating and quenching head H which is provided with a plurality of tips T,.adapted to direct a series of high temperature heating flames against a circumferential zone of the inner surface of the liner, and a row of quenching outlets Q, adapted to direct quenching jets upon previously heated circumferential zones.

The variable speed drive V enables the relative rate of movement of the carriage C to be I retarded as an initial' zone of the inner surface is being heated; to be accelerated'as a zone op- Apparatus for hardening the outer surface of a smaller body. such as a shaft, may be substantially identical with that justdescribed, except a smaller heating and quenching means H", as in Fig. 11, is mounted on the carriage C for I hardening a shaft W" which has a diameter less than that of the roll- W. As before, specific features of such apparatus and operation thereof.

will be come apparent from a later more detailed description.

Referring again to the apparatus of Figs. 1-7,

and more particularly to Figs. 1 and 2, the liner W is disposed in a tubular holder I5. the upper end of which is provided with an enlarged hexagonal portion i6 and the lower end of which extends downwardly through and is journalled in a suitable aperture in a circular track I! and a plate l8 of the carriage C. The lower end of the holder !5 is provided with a lip or flange l9 which extends inwardly just past the inner edge of the liner W, as in Fig. 2, and upon which'the lower end of the liner rests; and the lower end of the holder is also provided with a plurality of apertures 20 which permit a circulation of air about the outer surface of the liner W, thereby minimizing the possibility of the liner being distorted during the hardening operation. 1

The, liner W is positioned centrally in the holder l5 by a plurality of plungers 2|, three in the present instance, which extend through suitable holes in alternate sides of the upper hexagonal Portion 15 of the holder and which are spring-loaded to press resiliently against the outer surface of the liner with radial forces at spaced points distributed substantially equally about the circumference of the liner. 2!- heating and thereby prevent possible binding and consequent misalignment of the liner during treatment. For this purpose, springs 22 act be-- tween washers 23 and the outer ends of U-shaped brackets 24 to urge the plunger's 2| inwardly.

Washers 23 bear against suitable pins passing transversely through the plungers, While brackets 24, within which springs 22 are disposed and Plungerspermit circumferential expansion during.

alternate sides of the holder. To permit an un-' treated liner to be placed in the holder I5, or a treated liner to be removed therefrom, handles are attached to the outer end of the plungers and are provided with rounded cam-like ends which, when the handles are shifted to the position 25' of Fig. 2, will cause the plungers to be moved away from and out of contact with the liner. v

To permit rotation of' the holder l5, rollers 26 ride upon the track I! and are mounted on shafts 21, which in turn are attached to the remaining three sides of the hexagonal upper portion of the holder; and to effect rotation of the holder and liner W, a ring-sprocket 28 is mounted on the holder just below the plate l8 and engages a chain 29 which is driven from the motorM. he

' drive from the motor M to the chain 29 includes a gear 30 attached to the upper end of a vertical shaft, at the lower end of which is mounted a sprocket 3| in alignment with *the sprocket 28 and also engaging the chain 29. The motor M is preferably a small constant-speed motor which will rotate the liner W during the entire hardening operation :at the desired rate, which will usually be between 20 and l00 R. P. M. depending upon the size of the liner being treated.

' To assist its upward and downward movement, the carriage C is provided at its four corners with collars which slide on upright columns 38 of the framework F; and the carriage is also provided at eithe end-with a threaded collar 91, I

more clearly illustrated in Fig. 4, which engage threaded-shafts IB and 39/ Threaded

shafts

38 and 39 are driven from the motor A, which in this instance is a substantially constant speed alte'r-' nating current motor, and is directly connected to the variable speed drive V, which is provided with an adjusting wheel. 40 used in regulating the rate of movement 01' the carriage C; The variable speed drive V is also provided with a; reduction unit 4| integral therewith, and connected with the reduction unit 4| is a reversible clutch arrangement.

To eil'ect upward or downward movement of the carriage. a handle 42 of the reversible clutch arrangement'may be shifted to the left or right, as the case may be, to operate square. jaw

clutches

43 and 44 and cause rotation of a worm #5 in the necessary direction. Inthe reversible clutch arrangement, the handle 42 is operatively connected with a shaft upon which the movable laws of the clutches and 44 are mounted,- this shaft being splined upon the shaft of the worm 45; the clutch 44 is driven directly from the reduction unit 4| through ears 46 and I1: and the clutch 43 is driven indirectly from the reduction unit and the gear 46 through reversing gears work I", are cut away to permit operation of the chain It and India access to the sprockets 83 and I4.

The heating and quenchinghead H is mounted upon the upper end of a tubular support 51 which in turn is mounted upon a top plate 58 of an aux- ,iliary' framework 59 attached to channels It.

Passing through the tubular support, as in Fig. 3, are three tubes 90 and three pip s Bl. which respectively supply'a combustible mixture of gases, suchas oxygen and acetylene, and a cooling and quenching fluid, such as water, to the, head H and .thence to the heating tips T and outlets Q. To

permit a flow upwardly through the tubular support of air for secondary combustion oi the heating flames during the time that the head H is disposed'within the liner, the support lil is provided at its upper end with a plurality of holes 82; and to prevent cooling fluid, flowing downwardly from the inner surface during the hardening operation, from splashing due to impact with the top plate, a cone-shaped fluid collector is mounted thereon. The fluid collector 63 is provided at its lower end with circumferential apertures 64 which cause the fluid to flow relatively smoothly over the plate and drop into a shell 65, in which the entire apparatus is placed, thence to be carried away through an outlet 68.

To supply a cooling and quenching fluid, such as water, to the head H and the outlets Q, the three pipes 9| lead from a header 61 which is disposed beneath the plate 58 and to which is connected a pipe 68, provided with a control valve '89, and in turn connected with a suitable source of supply of the cooling and quenching flud.

,Tosupply a combustible mixture of gases to the head H and tips 'r through the tubes In, three blowpipes H are supported by a bracket 12 attached to thekauxiliary framework 59 and the outlet of each I the blowpipes is-connected with one of the tubes II, the proportions of the combustible mixture being adjusted by the usual blow pipe valves. A combustion supporting s. such as minimize possibility of thepresence of a highly 49 and 48' mounted upon an idler shaft 49 and a ear 50 meshing with the gear 48". The worm 45in tum engagesa worm gear 5 I, mounted upon the upper end of a vertical shaft which is journalled in a housing 52 disposed at one side of the threaded shaft 39, and the worm 45 thereby operates a sprocket .53 attached to the lower end of the vertical shaft. In horizontal alignmentwith the sprocket 53 are sprockets II, which, as

in Figs. 1 and 4, are attached to the .1ower ends of the threaded

shafts

38 and 99, while a chain 55, which encircles the

sprockets

59 and 54 in a triangular formation, effects rotation of the threaded shafts 3B and 39 and completes the drive from the motor M to the threaded shafts. As in Fig. 4, a portion of the inner edges of channels 89, which form" part oxygen, and a combustible gas, such as acetylene, are conveyed to the blowpipes by hoses l4 and 15, respectively, from three'control valves 18, inlets 11 of which may be connected to suitable sources a of gas supply. .A- common lever 18 is attached to thehandles of the'control valves, which are in the "01! position as shown in Fig; 1,. so that the flow of gases to all oi! the blowpipes can be turned on and of! simultaneously. The control valves are preferably of a quick-acting typeadapted to turn on the acetylene prior to the oxy en so that the heating flames may be ignited more easily, and also turn oi! the oxygen prior to the acetylene to oxidizing flame at the end of the treatment, which otherwise would tend to cause oxidization of the heated surfaces. 1

Referring now to Figs. 5-7 in which the heating and quenching head His illustrated in detail, the

. head H comprises a hollow tubular or ring-shaped body 80, a ring-shaped lower plate 9i, segmental of the base of the frame- 76 from the top of the liner so that the heating are connected to the lower plate 8| centrally of each of three arcuate-shaped combustible mixture distributing chambers 85, which are machined in the body 80 and the lower ends of which are closed by the plate Bl. Leading from the distributing chambers 85 are a plurality of vertical rows of outlet passages 86 threaded to receive the tips T, with the outlet passages of each vertical row being in staggered relation .with respect to the outlets of an adjacent row to provide a more even 10 heating effect.

Each of the cooling and quenching fluid pipes 6i is connected with one of the headers 83 at the lower .inner end thereof, and the cooling and quenching fluid is conducted through passages Bl, formed in each of the headers, to a nozzle 88, as in Fi 7. Each of the nozzles 88 directs the fluid downwardly against the lower surface 89 of a circular chamber 90, machined in the body 80, the circular chamber 90 having an inverted-L cross sectional shape and its upper end being closed by segmental plates 82 and headers 83, which are welded to the body 80 and to each other as previously described. Since the cooling fluid is directed by nozzles 88 onto the lower surface of the circular chamber, it is distributed evenly around the circular chamber and an even flow to the upper portion of the chamber and thence downwardly through a plurality of passages 9! will be assured; From the passages 9| the fluid will be directed onto the heated. surface through outlets Q at a slight angle downwardly and awayfrom the heating flames; which prevents any possibility of interference with the operation of the heating flames. The passages 9| and outlets Q are disposed between the vertical rows of tip outlet passages 86, 'as in Fig. 6, and the passages 9| are drilled between the arcuate gas distributing chambers 85 and the outer face of the body 80 to insure adequate cooling. 40

Further to correlate the various elements of the apparatus of Figs. 1-7, .just described in detail, a general description of the steps involved in hardening a workpiece or liner W now follows.

Assuming. that a liner has just been hardened (the blowpipes having previously been adjusted to give the correct mixture) that-the carriage C is in the full position of Fig. 4; that the heating gases and quenching fluid'have been shut off; and that rotation of the treated liner has been stopped; the clutch handle 42 is shifted to cause the carriage C to be moved upwardly to or above the dotted position of Fig. 4, the handles 25 moved outwardly, and the treated liner removed from the holder. The liner to be treated is then placed in the holder, and the handles 25 moved inwardly to position the liner centrally of the holder IS. The motors A and Marc then started, the clutch handle 42 being shifted to start the carriage on its downward journey and the initial rate of travel being retarded by adjustment. of the variable speed drive V through hand-wheel 40. The cooling and quenching fluid is turned on by means of the valve 69, andthe lever 18 is shifted to the "on position to turn on the heating gases, the 5 heating jets being ignited by a lighting blowpipe, which preferably remains lit during the entire. operation or series of operations and which preferably utilizes a mixture of air andacetlyene. The operation will then proceed substantially automatically, the only adjustment necessary being that of the variable speed drive V in order to insure a uniform heating of each successive zone of the inner surface in accordance with the principles previously outlined. As the head H issues flames no longerare directed upon the inner surface, the heating gases are shut off. and, shortly thereafter, the cooling and quenching fluid is also shut off. The motors A and M are then stopped, and the clutch handle 42 shifted to or through the neutral position, from whence the operation can be repeated for a new liner. It will be appreciated that instead of the entire inner surface, only a portion, or several portions, of the inner surface may be hardened if desired, and that the inner surface, or portions thereof, of tubular or 7 hollow bodies other than pump liners may be hardened by the apparatus of Figs. 1-7 or apparatus similar thereto.

Apparatus similar in many respects to that of Figs. 1-7, but adapted for hardening outer surfaces of bodies, particularly elongated bodies such as rolls, shafts, rods, tubes, and the like, is illustrated in Figs. 8-10 and Fig. 11. Such apparatus, as in Figs. 8 and 9, includes a framework F, similar to the framework F; and a carriage C, similar to the carriage C. and similarly adapted to move upwardly and downwardly along the framework by means of collars 35 sliding along uprightcolumns 36 and threaded collars 31 engaging threaded

shafts

38 and 39, which, as in the previous apparatus are provided with sprockets 54 at the lower ends thereof engaging achain 55 passing therearound. As before, the chain 55 also passes around a sprocket 53- mounted on the lower end of a vertical shaft, but in this instance the vertical shaft is driven from a gear reduction unit 4| coupled directly to the motor D, and the motor D is a direct current variable speed motor controlled through a rheostat R having a control handle 40'. As previously, the framework F is set in a shell 65, which collects the cooling fluid flowing therein, the fluid being carried off by a suitable drain.

Since in this instance the heating and cooling means is mounted on the carriage, the supportfor the body or workpiece W, such as a roll,

is attached to the framework and includes two pair of vertical angles 93 which are attached to channels 56 of the framework F, preferably by welding, and are also attached at the upper end of the framework to cross-beams similar to the channels 56. The space or slot between the closely spaced adjacent legs 94 of each pair of angles acts as a guide for the web of an I-beam 95, the'flanges of which are cut away atveither end to permit the web to be inserted in the slots. Each of the legs 94 is provided with a plurality of spaced holes 96 for receiving bolts 91 which enable the I-beam to be locked securely in position, and also enable the vertical position of the I-beam to be varied so that bodies of various lengths may be hardened, the

shafts

38 and 39, as' inFig. 9, being disposed at one side of the center line of the carriage to permit readier access to bolts 9-7. The upper center S, the point of which is inserted in the upper center of the .roll, is slidably mounted in a vertical bearing 98 attached to the I-beam,- and a weight 99 is attached to the upper 'end of the center to press the shaft against the roll to maintain an accurate alignment, but at the same time to permit vertical movement 'of the center while the roll or body expands during treatment and alsoto compensate for differences in length of various bodies which fall between any two of the spaced holes. In addition, the vertical bearing 98 is relatively long, and is machined accurately to relatively close tolerances, so that the upper end of the roll will always be kept accurately in alignment. In-

stead of beingweight-loaded, the upper center S may be spring-loaded to permit expansion of the body during treatment. I

In order to support the lower end W and maintain the same in accurate ali nment, the lower center 8 is rigidly supported by a framework I which is attached to a pair or horizontal angles IIlI spaced ashort distance apart in the same manner as angles 93, the lower. center S passing between the vertical legs of the of the roll' '5 angles, while a bearing I02, attached to the framework I00, and a thrust bearing I"; at-

which is driven by a chain III! from a sprocket,

I86 attached to the lower end of a vertical shaft. which is in turn driven by the motor M through a reduction unit I01 coupled tothe motor. As in the case ofthe motor M of the apparatus of vFigs. 1-7, the motor M is preferably a constant speed motor which will rotate the roll at the desired rate during thehardening operation, although if a considerable variety of rolls or shafts of various diameters are to be hardened, avariable speed motor may be found desirable.

' Referring now to Figs. 9 and 10, the heating and quenching means H mounted upon the carriage C comprises a plurality of water cooled blowpipe heads B and a ring-shaped. quenching block IIII, clamped by bolts III between upper and lower ring-shaped plates H2 and H3, respectively, the lower plate II3 being attached to the carriage 0'. Two blowpipes II are mounted on brackets 12' attached to the carriage at either side thereof, while. a combustion supportin gas, such as oxygen, and a combustible gas, such as acetylene, are conveyed to the blowpipes by hoses I4 and I5, respectively. Suitable apparatus for controlling the flow of gases to the blowpipes, similar to the valves I6 of the apparatus of Figs. 1-7, may also be provided, but, for the sake of clarity,-have not here been illustrated. From the outlets of the blowpipes, the

combustible mixture is led 'through QO-degrec adaptors II to headers II6, from which indi-.;

trated, ten heads are required, and each blow-- pipe and header serves five heads.

To prevent the heads B from becoming overheated, tubes II8 convey a -cooling fluid, such as water,'to each of the heads from distributing pipes H9, which are mounted on the carriage shell 65.

the rows are preferably varied when the blowpipe heads are assembled in the heating'and quenching head H, as in Fig. 9, so that alternate blowpipe heads will have three tips uppermost, and vice versa', in order to produce a more even heating eflect; also the tips themselves may vary in length, tips at the sides of the heads bei fl longer than those at the center in order to simulate the curvature of the surface of the roll W.

Each tip is threaded into a horizontal outlet passage I21, the upper row ofoutlet-passages leading from a distributing passage I2! and the lower row from a distributing passage I20. To convey the combustible mixture to the distributing passages and tips from the supply tube III, which is connected to an inlet I" in the inlet block, a pair 01 tubes III connect passages I22, leading from the inlet I30, with auxiliary passages I32 in the outlet block, which connect with distributing passages I20 and I29.- Aux-- iliary passages I33 lead into the distributing passages at points spaced between two outlet passages I21, in order to provide a more uniform. distribution of the combustible mixture to the tips.

To effect adequate cooling of the heads B, a cooling fluid distributing passage I35 is disposed between the'front face of the tip block and the plane of the combustible mixture distributin passages, cooling fluid being supplied thereto by an auxiliary passage I36 in the tip block and a tube I31 which connects the auxiliary passage with a passage I38 in the inlet block with which the cooling fluid supply tube H8 is connected.

From the cooling fluid distributing passage, outlets I39, disposed between the combustible mixture outlets, lead alternately to upper and lower spaces I40 and HI, respectively, which are formed between the tip block and the upper and lower plates by recesses in the tip block. From the spaces I MI and I the cooling fluid passes through the space or chamber I26 thereby cooling combustible mixture tubes I 3|, and thence through a passage I42 in the inlet block with which the discharge tube I2I connects.

water, and thence through inlet passages I to a circular distributing chamber I" formed in the block IIII. From the distributing chamber I45, the quenching fluid is, directed onto a heated surface zone throughoutlets Q, which are inclined slightly downwardly so that the quenching fluid will be directed away from the heating flames to prevent interference with the same.

Apparatus for hardening thev outer surface of a smaller body, such as a shaft, is similar to the apparatus illustrated in Figs. 8-10, except that for treating a shaft W", a heating and quenching means H", as in Flg.. l1, is mounted upon the Each of the blowpipe heads comprises an in-' let block I23, a tip or outlet' block I24, upper and lower plates I25, and-side plates similar to the upper and lower plates, all of which are preferably integrally united in a suitable manner, such as by welding, to form aunitary structure enclosing a chamber or space I26, as in-Flg. 10. Each outlet block carriestwo rows of tips '1, one

row containing three tips and the other row containing four tips, the tips in one row being disposed alternately with respect to the tips in the other row. In addition, the relative positions of carriage C instead of the heating and quenching means H. .The heating and quenching means H" comprises a plurality of water-cooled blowpipe heads-B and a ring-shaped quenching block carriage C, and the quenching-block and upper and lower plates being identical in shape and construction to the corresponding parts of the heating and quenching means H but smaller in size to correspond with the lesser diameter 'of the shaft w". Similarly, thev blowpipe heads 3',

source of supply thereof, or instead may be connected to outlets of the pipes H9 which. otherwise would be unused.

It will be obvious that by using separate blowpipe heads and quenching blocks, the same blowpipe heads may be used for a wide variety-of sizes of metal bodies, with only an occasional. change in tips necessary to provide equipment for hardening new or different sizes. Since blowpipe heads and several sizes of tips can be carried in stock, a new quenching head only being made after it has been determined that a new or different size is to be hardened, the cost of new equipment as well as the time necessary to put such equipment in operation is thereby reduced.

The operations involved in hardening the surface, or a portion thereof, of the roll W or the shaft W" are substantially identical, and will now be described briefly to correlate the previous general and detailed descriptions of the apparatus of Figs. 8-10 and Fig. 11.. The carriage C preferably having been run down to a point below the top of thelower center S, and the vertical position of the beam 95 having been adjusted and the roll or shaft mounted between the centers S and S, the motors M and D are started to effect rotation of the shaft anda movement of the carriage upwardly at a retarded initial rate of travel. Next, the heating gases andcooling water for the blowpipe heads B or B are turned on, the heating jets are lighted by a suitable air-acetylene or air-city gas torch, as before, and the quenching fluid is also turned on. As the initial zone or zones are heated and adjacent zones receive heat therefrom by conduction and also through preheating by the normally rising gases, the rate of travel is accelerated, and as the ,l pcr end of the roll or shaft is reached, the rate of travel is further accelerated. As soon as the heating flames reach the top of the roll or shaft, they are turned off, but the quenching fluid is left on until the uppermost heated zone has been quenched. The carriage is then run down to a I lower position below'the top of the center S, after 55 which the treated roll or shaft may be 'replaced with an untreated one and the hardening operations just described repeated.

Although the hardening operation has been heating and quenching'head, it will be obvious that the heads H. and H may be constructed as a unitary head, andseparate heating and quenching heads utilized instead of the unitary head H. Furthermore, the substantially constant speed motor A and its associatedvariable speed drive V of the apparatus of Figs. 1-? may be interchanged with the variable speed motor D of the apparatus of Figs. 8l1 without affecting the operation of either apparatus; and sources of power other than electric motors may be utilized. In addition, drilled orifices may besubstituted for the tips T, or a relatively thin slotted orifice corresponding in shape to the surface to be treated may be substituted for each horizontal row or series of tips T. In the latter instance, the relative rotational movement may be unneeded, since each slotted orifice will direct'a sheet of flame against the entire periphery of a circumferential zone.

While the principles of this invention have been .explained with reference to the hardening of effect over each transverse zone.

It will be understood that the apparatus, although described in detail with respect. to hardening cylindrical or tubular bodies, may be modifled for hardening other types of bodies, such as by changing the shape of the heating and quenching means and mounting the same at the side of the carriage for hardening the surface described with reference to an entire outer surface, only a portion of the'surface may be hardened by lighting the heating flames at the lower end of such a portion, and turning off the heating flames at the top of such a portion. It is usually desirable, however, to continue application of the quenching jets to a point above the last zonedirectly heated, in order to prevent any possibility of residual heat creeping back down the roll or shaft to reheat hardened portions and thereby reduce, though not destroy, the hardness imparted to the last zone or zones hardened.

While the heating and quenching means H and H" of the apparatus of Figs. 8-11 consist of separate heating and quenching heads, and the said surface.

of a plate, or by utilizing other heating and .quenching heads which correspond in shape to or are otherwise adapted to be utilized in hardening surfaces of gear teeth, rails, ways, and sur- I faces ofother metal bodies. It will alsmbe understood that other changes and modifications' LApparatus for heat treating an inner sur-- face of a hollow metal body comprising a framework and a carriage movable thereon; means mounted upon said carriage for supporting said body; means mounted on said carriage for rotating said body with respect to said carriage; means for simultaneously directinghigh temperature heating flames and jets of cooling fluid against adjacent lateral zones of said surface; and means for moving said carriage and said rotating body past said heating and cooling means so as to heat and cool successive zones of 2. Apparatus for heat treating an inner surface of revolution of a hollow metal body comprising means for simultaneously directing high temperature heating flames and jets of cooling liquid radially against adjacent circumferential zones of said inner surface; means for supporting said body with the axis of said surface,disposed centrally-with respect to said heating and cooling means; resilient means engaging the said body for maintaining said body in circumferential alignment and peniua ing means and said surface so as to heat and s cool successive circumferential face.

3. In apparatus for heat treating an inner-surgones of said surbustible mixture of gases; a distributing chambet at least partially disposed above said heating gas outlets for supplying said cooling outlets with a cooling'and quenching fluid; and a plurality face of a hollow metal body, means for directing high temperature heating flames substantially radially against a circumferential zone of said surface; a hollow support for said heating means, said support having a plurality of apertures therein adjacent said heating means for supplying secondary air for the combustion of said heating flames while said surface is being heated and means for effecting a relative longitudinal movement between said heating means and said surface so as to heat successive circumferential zones of said surface.

4. Apparatus for heat treating an inner surface of a hollow metal bodycomprising a vertical framework; a carriage movable upwardly and downwardly along said framework said carriage being adapted to support said body; means mounted on said carriagefor rotating said body with respect to said carriage; means for simultaneously heating and cooling adjacent circum ferent ial zones of said surface; means for moving said carriage downwardly past said heating and cooling means; and means for varying the rate of movement of said carriage.

5. Apparatus for heat treating an inner surface of a hollow metal body comprising an upright stationary heating and cooling head having a plurality ofcircumferentially disposedheatin flame outlets and a plurality of cooling fluid outlets disposed circumferentially beneath said heating flame outlets; means for supplying said head with a combustible mixture of gases and a cooling fluid; a hollow support for said head having a plurality of apertures therein adjacent saidhead for supplying secondary, air for combustion of said heating flames; means for supporting saidbody in a substantially vertical position and for moving said body downwardly past said heating and cooling head; and a substantially coneshaped fluid collector disposed at the lower end of said support for collecting the cooling fluid which flows by gravity from the lower end of said inner surface.

of cooling fluid passages extending downwardly from the portion of said cooling fluid distributing chamber disposed above said heating. gas outlets to said cooling fluid outlets and disposed between said heating gas distributing chamber and the outer wall of said head, the cooling fluid flowing through said distributing chamber and cooling fluid passages preventing overheating of the head and preignition of the combustible gases.

8. Apparatus for heat treating a surface of a metal body comprising a ring-shaped heating and cooling head having a plurality of circumferentially disposed heating flame outlets and cooling fluid outlets, said heating flame outlets dieing disposedin a plurality of vertical rows and said cooling fluid outlets being disposed beneath said heating flame outlets; .'a circular cooling fluid chamber formed within said head adjacent the inner side thereof; a plurality of passages con-' necting with said cooling fluid chamber and passing downwardly between said rows of heating flame outlets to said cooling fluid outlets; means for directing a cooling fluid onto the lower surface of said cooling fluid distributing chamber so as to cause said cooling fluid to be spread evenly about said lowersurface and vflow upwardly, thereby producing an even flow -to each of said cooling fluid outlets; and at least one heating gas distributing chamber formed in said body and disposed between said cooling fluid distributing chamber and said cooling fluid passages for supplying a combustible mixture of gases to said heating flame outlets.

9. A methodof hardening an inner surface of revolution of a hollow ferrous metal body which comprises directing high temperature heating flames and Jets of cooling liquid radially against adjoining circumferential zones of said inner surface; effecting a relative longitudinal movement between said heating flames and cooling Jets and said surface so as to heat and cool successive circumferential zones of said surface and thereby said body with radial forces at spaced points distributed substantially equally about the circum- 6. Apparatus for heat treating the inner surface of a hollow metal body comprising a vertical framework; a carriage movable upwardly and downwardly along said framework; means mounted upon said carriage for supporting said body, said supporting means including'a tubular depending member having an inwardly extending flange on the lower end thereof for supporting the lower end of said body and a plurality of rollersresting upon a track mounted-upon said carriage fornpen'nittin rotation of said body;

means for rotating said supporting means and said body; and means for heating and cooling successive circumferential zones of said inner surface.

7. Apparatus for heat treating a curved surface of a metal body comprising a heating and cooling head conforming in shape to said surface and having a-plurality of upper outlets for directing all" ference of said body to-maintain said body'in circumferential alignment with the path of such relative longitudinal movement so as to permit said body to expand and contract circumferentially during such hardening. v

10. A method of hardening an inner cylin dricai surface of a tubular ferrous metal body which comprises mounting said body with the axis of said inner' cylindrical surface in a subhigh, temperature flames against an upper lateral 'zone of said surface and a plurality of lower outlets for directing cooling jets against an adjacent lower lateral zone; adistributing chamber for supplying said heatin as outlets with a comstantially vertical position; supporting said body at its lower end so that the upper end of said body is freely movable vertically during longitudinal expansion and contraction of said body while undergoing the hardening treatment; rotating'said body about the 'vertlcal axis of said cylindrical inner surface; resiliently pressing against the outer surface of said body with radial forces at spaced points distributed substantially equally about the circumference of said body to' maintain said body centered about said vertical axis and permit circumferential expansion and contraction of said body while undergoing the hardening treatment; applying high temperature heat to successive circumferential zones of said inner cylindrical surface; and applying a quenchaeezese, 9

ing medium to successive circumferential zones of said surface so heated, to harden the same.

11. Flame hardening equipment including a torch block with separate distributing chambers therein extending in difierent directions, and a group of jet orifices opening from each of said chambers, and a separate shut-0E valve for controlling the supply of gas to each chamber.

12. Flame hardening equipment including a torch block with three or more separate disi0 tributins chambers therein, some of which extend in difierent directions and a group of Jet orifices opening from each of said chambers, a