US2376515A - Apparatus for and method of quenching - Google Patents

Description

May 22,1945. H. E. SOMES ,37

APPARATUS FOR AND METHOD OF QUENCHING '7 Filed Nov; 21, 1941 2 Sheet$ -Sheet 2 INVENTOR HOLDGId ,E. Somes BY aw A TTORNE Y Patented May 22, 1945 UNITED STATES PATENTQOFQFICE APPARATUS FOR AND Ms'rnon or QUENCHING Howard E. Somes, Detroit, Mich, assignor to Burn.

Induction Heating, Inc., Philadelphia, corporation of Michigan Pa., a

Application November 21, 1941, Serial No. 419,828 11 Claims. (Cl. 148-2155) This application is a continuation in part of my copending application Serial No. 336,129, filed May 20, 1940, for heat treating apparatus which has matured into Patent 2,358,834.

This invention relates to a method of quenching articles during a heat treatingprocess with respect to which it is desired to improve the physical characteristics thereof by zone hardening, and to the apparatus for carrying out the quenching operation. Although the present invention is applicable to the heat treatment of the external are caused to uniformly flow almost entirely in the annular zone being heated and are so concentrated that the temperature of the zone affected is raised to hardening temperature before any substantial amount of heat can drift to the core or the back metal of the piece immediately I adjacent such zone, The required heat is almost instantaneously generated in this zone to a uniform radial depththro'ughout the same.

It is the primary object of the present invention to so quench the heated zone that the thermal energy is removed not only at substantially the same rate as that at which it was'generated but also uniformly throughout the annular extent thereof,and with a minimum of elapsed time character shown in my said copending applica between the termination of the heating operation and the application of the quenching mediumQ Another object is to bring the foregoing about as will hereinafter appear through the accurate control of such features entering into the quenching operation as thecharacterof flow and distribution of the quenching medium, the relation of the time and rate of quenching medium application with respect to the heat operation and the proximity of the quenching apparatusto the v I surface of the zone being heat treated.

A further object is to provide new and improved quenching apparatus'of simple and economical yet, extremely eflllcient construction capable of discharging .a. solid annular wall of quenching medium at desired velocity and volume into uniform contact with a heated cylindrical surface with a minimum of turbulence.

With the above and other objects in view, which, from the following detailed description, will be apparent to those skilled in the art to which the invention appertains, the present invention consists in certain steps in the new and I improved method and in certain features of construction and combinations of parts to be hereinafter described with reference to the accompanying drawings and then claimed.

In the drawings in whlchpne suitable embodiment of the quenching apparatus has been selected for the purpose of illustration of the present invention,

Figure l is a vertical section of the quenching head in cooperative association with an induction heating head;

Figure 2 is a transverse section taken approximately on the line 2-2 of Figure 1 showing certain of the axial passages for the flow of quench ing medium;

Figure 3 is a transverse section taken imately on the line 3-43 oi Figure 1; and

Figure 4' is a greatly enlarged fragmentary section taken through the two annular members to more clearly show the conical passageway defined by these two members, the support for the inner member being indicated in broken outline.

Referring to the accompanying drawings in which like numerals refer to like parts throughout the several views, there is shown in Figure 1 one suitable embodiment of a quenching head Q in operative association with an induction heating head H, the heating head H being of the general tion Serial No. 336,129, suitable for heat treating the internal urface of a tubular cylinder C throughout a annular zone Z to a predetermined uniform de Briefly the duction heating head H, which structurally forms'no part of the present invention, comprises a tubular heating coil 6 carried by a laminated magnetic core I which in turn is carried by a suitable mandrel or conductor 8, one

end of the coil 6 extending through the conductor 8 in communication with a ported'chamber '9, a part of which is normally closed by a suitable valve such as a ball element to. The coil 6 is cooled by the passage of a suitable coolant therethrough which exhausts into the chamber 8.

When the head 1-1 is operative to induce heating currents in the workpiece C, the ball element 811' is raised from its seat to permit the coolant to discharge through the port of chamber 9 in a manner to be hereinafter described.

Although not shown in the drawings the heads H and Q are normally spaced apart, and after the workpiece or tube C to be heat treated is located by means of any suitable work holder (not shown) in proper position for heat treatment the induction heating head H and the quench head Q are brought into axial registration, as illustrated in Figure 1. The lower end of the tube C at this time is axially upwardly beyond the heating coil 6. The tube C is then propelled downwardly relative to'the heads H and Q at a uniform rate of travel and at a predetermined time with respect to the downward travel of the tube C the coil 6 is connected with its source of high frequency energy and the head Q is connected with its source of quenching medium. During this movement in a downward direction, as viewed in Figure 1, the internal surface of the tube C is progressively heated and quenched, the tube or heads also being rotated during such movement to insure uniform application of the heating currents and the quenching medium. It is to be appreciated, of course, that the heads H and Q may be axially moved instead of the tube and, also, that the tube and heads may be disposed for relative axial movement in a horizontal direction instead of in the vertical direction, shown in Figure 1, for performance of the heat treating operation.

Before describing the method of the present invention, the quenching apparatus will first be described in detail in order that a clear understanding may be had of the same. The quenching apparatus is extremely simple in construction since it merely embodies three parts, namely, a main stem or supporting arbor Ill, a first annular member II carried by the arbor I and a second annular member I2 carried by the member II and cooperating therewith as will soon appear to provide the passages and nozzle orifice for the quenching medium. These elements are constructed of suitable corrosion resistant material, such as, for example, stainless steel.

The arbor I0 is tubular in cross-section for a portion of the length from its lower end to provide a chamber I3.within the bore thereof to receive quenching medium, such as water under high pressure, from-a support (not shown) to which it is secured by means of internal threads II. The upper or solid end of the arbor is provided with external screw threads I5 and a circumferential chamber I6 intermediate the threads-I5. This chamber receives the quenching medium from the chamber I3 through a plurality of generally axial passages I'I communieating with the chamber I3 through the bottom of the bore of the arbor I0. It is preferred that the total transverse area of passages I1 be at least about one-half the transverse area of the chamber I3 in order to provide an increase in velocity of the quenching medium flowing therethrough.

The first annular member I I is generally tubular, it having a narrow cylindrical head I8 at its upper end, as viewed in the drawings, a cylindrical outer surface 89 of reduced diameter intermediate its ends, an externally threaded portion 20 adjacent its lower end terminating adjacent the cylindrical portion 59 in a circumferential recess 2| to provide a downwardly facing shoulder 22, and a conical surface 23 extending .be-, tween the head It and the cylindrical surface I9. The conical surface 23 inclines in axial crosssection upwardly and outwardly from the upper end of the cylindrical portion I9 and terminates radially inwardly of the periphery of the head l8 to form therewith a downwardly presented annular groove 24. As seen in Figure 4, the bottom wall 25 of the groove 24 is arcuate in contour, it being tangent at one side to the conical wall 23 and tangent at the other side to a downwardly and outwardly inclined conical wall 26 of appreciable length which terminates substantially at the lower peripheral edge of the head l8.

The purpose of the downwardly presenting annular groove 24 is, as will later appear, to divert a generally upward fiow of the quenching medium to a general downward flow.

The cylindrical portion I9 of the member II is provided with upper and lower rows of radial passages 21 extending therethrough, the passages of One row being staggered with respect to the passages of the other row. The transverse sectional area of the individual passages is relatively small, there being as many as 60 such passages in such cylindrical surface having a diameter, for example, of 2 whereby such small passages will tend to minimize the turbulence of the flowing quenching medium.

The second annular member I2 is of substantially the same external diameter as th member II and the lower portion of its internal wall is cylindrical and threaded as indicated at 28 and being recessed to provide a radial shoulder 29 and a cylindrical surface 30 of a diameter very slightly greater than that of the cylindrical surfac I9 of the member II. The upper portion of this inner wall is of conical formation, tapering upwardly and outwardly at 3I from thecylindrical surface 30, the region at which such taper is initiated being spaced radially outwardly an appreciable distance from the cylindrical surface 30. The annular upper end of the member I2 is in the form of a convex arcuate surface 32 tangent at one end termination to the surface 3| and tangent at its other end termination to a downwardly and outwardly inclined wall 33 which extends to the outer periphery of the member I2 near the upper end thereof. As seen in the drawings, particularly Figure 4, the angle of inclination of the wall 33 is the same as that of the wall 26 of the member II and the angle of inclination of the wall 3] is greater than that of the wall 23 of the member II so that these walls converge from the cylindrical surface I9 toward each other. The arcuate walls 25 and 32 terminate at the radially inner ends of the spaced conical walls 26 and 33 which provide the orifice for the discharge of the quenching medium. It is to be noted that this orifice is continuously open circumferentially, and free from any projections which might tend to produce turbulence.

The member I2 is threadedly receivedon the member I I as shown in Figure 1 and in assembled relation the shoulder 29 of the member l2 abuts the shoulder 22 of member II to predetermine the relative threading movement of these two members toward each other and thereby provide fOr a predetermined axial spacing between the bottom wall 25 of the groove 24 and the convex surface wall 32 of the member l2. It will be seen that the part of the cylindrical portion of mem-- her II which is disposed below the lower row of passages 21 is received within the cylindrical surface 38in close relation therewith.

The inner surface of the inner annular memlber II is provided with a radial shoulder 35 and is internally threaded to be threadedly received by the threads l5 of the mandrel with the shoulder 35 firmly abutting a corresponding radial shoulder spaced slightly from the upper end of the mandrel In in an axial direction to properly axially locate the member H on the mandrel 10.

It is to be noted that the inner wall of member II is provided with a circumferential channel 38, rectangular in cross-section, intermediate the ends of the threads thereof and into which the radial passages .21 open. When the member II is assembled to the mandrel I0 the channel 36 is in exact registration with the channel I6 of mandrel In to provide an annular chamber within the members Ill and II.

These two members, In and II, provide a continuous passageway for the quenching medium from the chamber I3 of the mandrel l0 through the passages l1. into the chamber defined by the channels IS'and 36, thence through the radial passages 21 into the annular chamber 31 defined by the converging conical walls 23 and 3|, and finally through the space betweenthe parallel walls 26 and 33 in a direction away from the direction of movement of the heads H" and Q as represented by the arrow 38 into angular co tact with the inner surface of the tube C.

The radial passages 21 for the flow of quenching medium from the chamberprovided by the channels l6 and 26 are so arranged and contoured This alignment of the quench head Q with the heating head H is accomplished by providing the 7 upper ends of the member H and the mandrel as to insure a high velocity fiow of the quenching medium with minimum turbulence. These passages are of primary importance in producing proper flow of the quenching medium, The quenching medium is introduced to the chamber it under high pressure which at times may be as great as, for example, 60 pounds per square inch or more and is discharged at high velocity substantially free from turbulence, the passages l1 causing a first increase in velocity. The small passages 21 being of a total area at least as great as that of the openings I! serve, (by reason oftheir small individual area, to straighten It with recesses 39 and 40 whereby the recess 40 receives an accurately interfitting part 4| of the heating head H with the result that the quenching head is constrained to concentricitywith the work surface C. Another important feature is that the work C is moved relative to the quench head Q at the same rate as. it is moved relative to the heating headH. This rate of movement is uniform and may be in the nature of, for example, one inch per second depending,

of course, upon the characteristics of the metal being heat treated and the rate of power input.

In practice it is preferred to have a small tolerance between the elongated barrel 34 of the quench head H and the work C being heat treated in the neighborhood of .10 of an inch or less such that during relative movement between the quench and work an injector action is provided tending to maintain the space between the quench head and the work completely fille with the quenching medium without permitting the quenching medium to back up toward the heating coil. Also, the tolerance should not be so large as to cause an elector action tending to produce erratic quenching.

Due to the angle of projection of the quenching medium which is preferably between 25 and degrees with respect to the axis of the work, as indicated at A in Figure 4, depending upon the smoothness of. the work being quenched, and .due

to the relative movement between the work and the quench head the quenching medium engages the work surface in such manner that it is restrained from deflecting upwardly toward the head coil or the work surface being heated, to imthe quenching medium flow to an even radial flow into the chamber 31 where the velocity is this time greatly increased up to the point of entrance into the discharge orifice between the parallel walls 26 and 33. Thisis due to the fact that the area of this chamber uniformly decreases throughout its extent from the cylindrical wall I9 to the spacebetween the arcuate surfaces 24 and 32. Moreover, the walls of this chamber are free from sharp turns and are extremely smooth. In order to insure smoothness of the pair the heating efllciency. Here again is an important feature in the present invention. By the construction described I am enabled to arrange the initial contact of the quenching medium with the heatedwork surface in, closely spaced axial relation with the trailing end of the heating coilso that the application of quenching medium subsequent to heating is extremely rapid,

the delay being only that period of time required for the tube C to traverse the distance substantially equal to that between the trailing end of the heating coil and the orifice provided by the parallel walls 26 and 33 It is to be readily appreciated that the elapsed time between termination of heating and the application of quenching medium ls'relatively small since the rate of movement is preferably in the neighborhood of one inch "per second. Moreover, by directing the quenching medium at an abrupt angle a more drastic quench is obtained which results in greater heat-removal over a given period of time than is the flow is again quieted since the walls 26 and possible with a slight angle of quench direction.

A further step of importance is that of rotatsurface to compensate for any irregularities in quench application such as, for example, small dirt particles which may become lodged in the discharge orifice and produce erratic quenching.

There may be some tendency in the case where a rough surface is being heat treated for the quenching medium to tend to back up toward the heating coil due to the resistance to fiow presented by such surface.

In order to insure against this suitable means may b provided for introducing a dry inert gas under pressure into the bore of the tubular member being heat treated ahead of the heating and quench head such that it will act directly against the discharging quenching medium and prevent flow of the same toward the heating coil. Another method of preventing backward flow of the quenching medium is to create a negative pressure within the bore between its leading end and the quench head such that an injector action is presented whereby to positively draw the annular wall of quenching medium through the annular space between the bore area undergoing quenching and the barrel of the quench head.

By thus substantially instantaneously applying a large volume of quenching medium after heating under high pressure and with little if any turbulence, and in such direction and manner as to maintain an axially flowing wall of quenching medium of considerable axial extent in contact with the heated surface at a predetermined distance from the immediate area being heated, I am enabled to control the hardness developed, the depth of hardness and the area being treated within exceedingly close limits. i I

In accordance with the present invention the quenching medium is applied in such volume, with such uniformity and at such an angle that the thermal energy is extracted from the annular heated zone at the same rate and rapidity as it was generated thereby preventing the same from drifting to the back metal to insure not only uniformity of hardness but also uniformity in depth of hardness.

The uniformity and rapidity in quench application attainable by the present invention is very advantageous inthat it holds distortion of the Work being treated to a minimum. Of greater importance, however, is the fact that by reason of the rapid quenching action herein described a fine grained martensitic structure is produced, the structure of the martensite being very much finer than that ordinarily produced by known quenching methods.

It will be noted that the mandrel I is recessed at 44 to threadedly receive a hollow screw 46 having radial passages 41 therein communicating with the recess 44, and that the chamber 45 below the screw 46 communicates through radial passages 49 with an annular chamber 50 defined by the mandrel I 0 and a thin walled extension SI of the member ll. These features do not form a part of the present invention. For the sake of clarity of the structure illustrated in operation these features come into play when the quench head Q is registered with the heating head H. While'the two heads are being registered the screw 46 raises the ball valve 9a from its seat. This opens the passage for the flow of coolant through theheating' coil so that it can be discharged. The coolant thus flows into'recess 45 through the hollow screw 46 and outwardly through the passages 49 where the tubular extension constrains the same to fall in an annular body straight downwardly out of contact with the walls of surrounding work C.

The quenchhead Q while of extremely simple construction and capable of being readily assembled and disassembled for 'cleaningis so constructed as to insure maximum emciency of operation with the insurance that the circumferentially continuous unobstructed orifice will always be maintained in proper adjustment.

It is to be understood that various changes may be made in the construction andarrangement of parts without departing from the spirit of the invention as will be apparent to those skilled in the art, and that reference therefore should be had to the appended claims for a limit of the definition of the invention.

. What is claimed is:

1. A quench head comprising an arbor portion having an axial quench fluid conducting passageway therein, cylindrical means coaxial with said arbor portion having axially spaced annular wall portions providing a circumf rential nozzle passage and spaced annular walls extending radially inwardly from said nozzle passage wall portions to provide an annular chamber radially outwardly of said axial passageway, said chamber uniformly decreasing in area in the direction of said nozzle passage, and means for radially conducting quench fluid from said axial passage umformly annular wall portions providing a circumferential nozzle passage and spaced annular walls extending radially inwardly from said nozzle passage wall portionsto provide an annular cham- 4o ber radially outwardly of said axial passageway,

said chamber uniformly decreasing in area in the direction of said nozzle passage, and means for radially conducting quench fiuid from saidaxial passage uniformly into said chamber throughout the inner periphery thereof, said walls being of frustro-conical formation and converging toward said nozzle passage wall portions and both inclining away from a transverse plane through said arbor portion, said-nozzle passage wall portions having arcuate surfaces tangent to said chamber walls and parallel frustro-conical surfaces tangent to said arcuate surfaces and inclining from said arcuate surfaces toward such transverse plane.

3. A quenching head comprising a tubular support having a nozzle assembly supporting head, a nozzle assembly thereon comprising telescopic annular inner and outer members, the inner member having a sleeve shank and an annular outwar of, and thetouter member being threaded on said sleevefand having an annular lip cooperating with said first-named lip to provide an annular orifice, said sleeve shank having apertures therein and said head having a passage extending radially from the inside of said tubular support, said shank apertures and said head passage being adapted to establish communication between the space betweensaid annular lips and the inside of said tubular support.

4. A quenching head comprising a tubular support having a nozzle assembly supporting y extending lip at one end therenular outwardly extending lip at one end thereoi, and the outer member being threaded on said sleeve. and having an annularlip cooperating with'eaid' flrst-name'd lip to provide an annular oriflce, said sleeve shank having apertures therein and said head having a passage extending radially from the inside of said tubular support, said shank apertures and said head passage being adapted to establish communication between the space betweensaid annular lips and the inside of said tubular support and said head having a passage therethrough from one side thereof to a point on the other side outside. of said tubular support. V

5. The combination in a quench head of a supporting arbor having a fluid transmitting passage therein for quenching fluid, and a'radially extending chamber of less flow area than said passage, nozzle forming members removably mounted on said arbor having an annular nozzle passage oi progressively reduced flow area communicating with a discharge opening having a flow area no'greater than the narrow nor-- tionoi said passage, whereby quenching fluid flows through said arbor to said nozzle opening at a progressively increasing velocity and is expelled through said opening" at its highest v'elocity.

8. The combination in a quench head of a sup- 7 porting arbor having a fluid transmitting passage therein ior quenching fluid, and a radially extending chamber or less flow"area than said passage, nozzle forming members on said arbor having an annular nomle passage of progres-' sively-reduoedflow area communicating with a discharge opening having a flow area no greater than the narrow portion of said passage,

whereby quenching fluid flows through said arbor to said norzle opening at a progressively increasing velocity and is expelled through said open- I ing at its highest velocity.

7. The combination in a quench head of a supporting arbor having a fluid transmitting pasertured wall between said chamber and said nozzle passage for transmitting fluid evenly from said chamber to said nozzle passage, whereby the flow of quenching fluid continuously increases in I velocity from said arbor passage'to said nozfle v means for transmitting fluid evenly from said chamber to said nozzle passage, whereby the flow of quenching fluid continuously increases in ve- "locity fromsaid arbor passage to said nozzle openin and is discharged through said openin at its highest velocity.

10. In the heat treatment or a longitudinal suriace of a metallic article wherein successive lon- ,gitudinal increments of the surface are progressively heated and quenched through the spaced application of heat and quenching fluid while etiectingw relative movement longitudinally of said surface betweenthe article and the awlications A of heat and quenching fluid, the method or preventing the quenching fluid irom flowing in a direction longitudinally toward the application or heat from the region or application of quenching fluid to said surface, which consists in directing the quenching fluid in a direction away from the region of heat application into initial contact with said surface-at such pressure and angle to said surface o i' less than degrees and so conflning the quenching fluid upon contact with said surface to flow longitudinally along said surface sage therein for quenching fluid and a' radiallyextending chamber oi less flow area than said passage, means providing an annular nozzle opening ior discharging an annular solid stream of quenching fluid from said head at a 'predetermined angle and having a nozzle passage con- 4 meeting said chamber with said opening, the walls ertosaid opening, andmeans or said passage tapering from said chamber to said opening, whereby the flow of quenching fluid continuously increases invelocity from said arbor passage to said nozzle opening and is discharged through said opening at its highest velocity.

8. The combination in a quench head oi. a supporting arbor having a fluid transmitting passage therein for quenching fluid and a radially extending chamber 01' less flow area' than said passage, means providing an annular nozzle opening for dischargingan annular solidstream of quenching fluid from said head at a predetermined angle and having anozzle passage connecting said chamber with -said opening, the

as to produce a velocity of quenching fluid at the region or initial contact that will create a zone of negative pressure within said angle immediately adiacentsaid region or initial contact.

.11. Inamethod oi'hardeningaperimetral surface of a metallic article wherein successive longitudinal increments thereof are progressively heated and quenched through the spaced application of heat and quenchin fluid while eflecting relative movement longitudinally of said suriace between the article and the applications of heat quenching fluid, the step of directing a solid high pressure annular stream of quenching fluid in a direction awayi'rom the application of heat and quenching fluid into' ous contact with said surface at such pressure andangletosaidsuriaceoi'less thanaiidegrees andso confining the quenching fluid to annular flow 'i'rom the region oi initial contact along said surface. longitudinally away from the application or heat as to producer. veiocityot quenching fluid at the region orinitial contact that will create a zone or negative pressure within said angle imwalls 0! said passage tapering iron: said charm including an a'p mediatel adjacent said region of initial I a. some perimetrally continu-

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