US2297293A - Flame hardening apparatus - Google Patents

Description

Sept. 29,'1942. R. o. DAY ETAL 2,297,293

` FLAME HARDENING APPARATUS E Filed oci. 9, 1940 4 sheets-sheet 1 7/ I T'K'T /0 2522'- j BY ATTO R N EY Sept'. 29, 1942.`

R. O. DAY ETAL FLAME HARDENING APPARATUS 4 Sheets-Sheet 2 Filed Oct. 9, 1940 T Q. Q Q @QW/ QQQT ,QQQ\ QQQ QQQ WQQ@ QQQ QQ QQ QQM. Q Q.

INVENTOS y o. DAY RT w. cowlN ATTORNEY SePt- 2.9,. l942 R.' o. DAY. Erm.I 2,297,293

FLAME HARDENING APPARATUS Filed oct. s, 1940 4 sheets-sheet 5 6,7 f5 5f if ,/,M/

lNvENToRs ROGER O. DAY

HERBERT W. COWIN l ATTORNEY Sept. 29, 1942. R,4 Q DAY Erm, 2,297,293-

FLAME HARDENING PPARATUS Filed oet. 9, '1940 4 sheets-sheet 4 INVENToRs ROCERr O. DAY HERBRT w. cow|N Patented Sept. 29, 1942 FLAME HARDENING APPARATUS Roger O. Day and Herbert W. Cowin, Westfield,

N. J., assignors to The Linde Air Products Company, a corporation of Ohio Application October 9, 1940, Serial No. 360,424

.2 Claims.

This invention relates to llame hardening apparatus and more particularly to apparatus for flame hardening interior surface portions of generally tubular metal articles, such as drill pipe couplings.

In ame hardening, high temperature heating flames are applied to a surface of a hardenable metal article to heat the surface to the desired depth and to a temperature at or above the critical range; and a quenching medium, such as water, is applied to the heated surface to cool the same at a relatively rapid rate, it generally being desirable to apply the quenching medium as quickly as possible after heating. VIn flame hardening inner or interior surface portions of generally tubular metal articles-and particularly relatively large articles, such as drill pipe couplings, which require relatively large amounts of heat and therefore necessitate the use of apparatus which nearly lls the interior of the article--it is inconvenient as Well as time consuming to withdraw the heating means and then insert a quenching device. Also, the relatively large amounts of heat in the confined space in the interior of the article tend to cause the apf paratus to become overheated and/ or outer parts thereof to be melted, fused, or otherwise damaged. Thus, apparatus for iiame hardening inner surface portions of generally tubular metal articles should be as compact as possible, should have sufficient heating capacity to heat the surface portions to be hardened relatively quickly, should be adequately cooled, and should be capable of cooling the heated surface portions substantially immediately after heating.

Among the objects of this invention are to provide apparatus for ame hardening inner surface portions of generally tubular metal articles, by which such surface portions may be uniformly heated; to provide such apparatus by which such various congurations in the interior of such an s article; and to provide such apparatus which is particularly characterized by its ease and rapidity of operation.

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

Fig. 1 is aside elevation of apparatus which includes a novel heating and quenching device and which is constructed in accordance with this invention, in operative position for flame hardening surface portions in the interior of a female drill pipe coupling;

Fig. 2 is an end elevation of the apparatus of Fig. 1;

Fig. 3 is an enlarged side view of the heating and quenching device of Fig. 1;

Fig. 4is a rear view of the heating and quenching device;

Fig. 5 is a longitudinal sectional view of the heating and quenching device, taken along line 5-'5 kof Fig. 4;

Fig.I 6 is a longitudinal sectional view of a wing of the heating and quenching device, taken along line 6-6 of Fig. 4, and illustrating more clearly heatingr gas passages formed in the wing;

Fig. 7 is a front View of' a 'special block and associated tips for heating a shoulder formed in the interior of the coupling of Fig. 1;

Fig. 8 is a longitudinal sectional view taken through a wing of the heating and quenching device, along line 8'-8 of Fig. 4, and illustrating more clearly cooling passages formed in the wing; and Y Fig. 9 is a transverse sectional view taken near the front end of the heating and quenching device, along line 9--9 of Fig. 5.

Apparatus constructed in accordance with this invention, as illustrated in Figs. 1 and 2, includes a rheating and quenching device D adapted to heat and cool surface portions in the interior of a tubular metal article. As illustrated herein, the article being treated is a female drill pipe coupling P, having threads l0 and a shoulder Il against which the entering male half of the coupling abuts when two sections of drill pipe are secured together. The couplingrP is mounted for rotation at a relatively rapid rate, such as between 50 and 120 R. P. M.

'Ihe heating'and quenching device D comprises a body formed with three equally spaced longitu- -dinal wings W, which taper outwardly from front to rear as do threads lll. Each wing carries three longitudinal rows of tips T, which direct heating arnes against threads IIJ` as the coupling rotates. The center row of tips in each wing extends outwardly further than the two outer rows of each Wing, to correspon-d to the transverse curvature of the interior of the coupling. Disposed in the valleys between wings W are three quenching tubes I2, which are provided with slots I3 for discharging a quenching medium, such as water, into the interior of the coupling P at the completion of heating. As is shown more clearly in Fig. 3, slots I3 lextend longitudinally of each tube and may be disposed in two rows, so that a relatively large amount of quenching medium may be discharged into the interior of the coupling in a relatively short time.

Quenching tubes I2 may extend to the front end of the device D, or may terminate a short distance from the front end when shoulder II is to be hardened and the device is provided with three tip blocks K partially disposed in the valleys between the wings and carrying `a plurality of tips T' which direct heating ames against shoulder II.

Tips T and T are supplied with a combustible mixture of gases formed in three blowpipes B, each of which supplies the tips of one wing and one block K. Blowpipes B., heating and lquenching device D, and other portions of the apparatus, are supported on a carriage C which is mounted on and slidable longitudinally of a framework F. Carriage-#C and framework F may be. parts :of Aa lathe, and the article to be treated, or coupling P, may be mounted on the head stock of the lathe. Carriage C is movedforwardlyand rearwardly only in inserting or withdrawing theV heating and quenching device from the article being treated. Y

The heating flames directed lagainst threads I and shoulder II are preferably produced by a mixture of oxygen and acetylene, supplied to blowpipes B by hoses I4 and I5, respectively. The now of oxygen and acetylene to the blowpipes through hoses I4 and I5 is controlledV by valves I5, one valve being provided for each blowpipe, but handles Il of valves I6 preferably being connected by a common lever I8 for simultaneous operation. Valves I6 are preferably of a snap action type, and also so constructed that the oxygen is turned off before the acetylene, so that a highly oxidizing ilame will not attack a highly heated surface. Control valves I6 .are mounted upon a bracket I9, secured to carriage C, and inlet hoses and 2| of control valves I6 are connected to any suitable source of supply of oxygen and acetylene, respectively. Blowpipes B are adjustably mounted on vertical brackets 22 by clamps 23, and the lower ends of brackets 22 are secured'to the carriage C in any suitable manner, such as by bolts, as shown. Blowpipes B may be of any conventional type provided with a suitable mixer and valves, such as oxygen regulating valves 24 and acetylene regulating valves 25, for controlling the proportions of the gases passing to the mixer. bustible mixture passes from the blowpipes to the heating and quenching device through tubes 26, which are provided with cooling jackets 21.

For circulating a cooling medium through the device D, blowpipes B, and jackets 21, a suitable cooling medium, such as Water, is supplied lby a hose 29 to a header 3B, from which tubes 3| lead to wings W and tubes 32 vlead to jackets 21. As is illustrated more clearly in Figs. 2 and 5, tubes 32 connect with jackets 21 closely adjacent the heating and quenching device D, and the cooling medium flows through the jackets to the opposite ends thereof, thence being conveyed to blowpipes B by tubes 33. After circulating through blowpipes B, the cooling medium is discharged through tubes 34, which are bent around, as shown, so as to discharge the cooling medium into a pan 35 The com-y secured to framework F beneath carriage C. The cooling medium supplied to wings W is circulated through the device D and is conveyed therefrom by a pipe 36, which also discharges into pan 35.

Used cooling medium may be drained from pan 35 by a pipe 31 leading to a sewer connection. or, if a cooling medium more expensive than water is used, to a circulating pump (not shown). In the latter instance, the cooling medium may be passed through cooling coils, if necessary, and then back to hose 29 for re-use.

For quenching purposes, a suitable quenching medium, such as water, is supplied by hoses 39 to a valve 40, mounted on carriage C. From valve 40, .the quenching medium passes through a relatively large hose 4| to a header 42, which distributes the quenching medium equally to the three quenching tubes I2.

The heating and quenching device D is mounted on the carriage by a U-shaped bracket 43, the upturned ends of which are provided with clamps 44 secured to pipe 36 and the base of which is welded or otherwise suitably secured to the upper ends of a pair of posts 45. JThe'lower ends of posts 45 are bolted or otherwise suitably secured to carriage C. To provide a more rigid structure, pipe 36 and quenching tubes I2 pass through suitable holes in a pair of transversely disposed, triangular plates 46, the pipe and quenching tubes being securely aiiixed to the plates by welding, or in any other suitable manner.

The heating and quenching device D, as in Figs. 3 5, consists of a body or block fof suitable metal, preferably formed by casting to provide an interior space `or chamber 48 and the wings W. The front end `of chamber 48 is closed by a plug 49, welded or otherwise suitably secured to the block; while the rear end of the chamber communicates with pipe 36 which also is welded, brazed, or otherwise suitably secured tothe block. Each wing W is provided with va longitudinal raised portion or platform 50, as in Figs. 3 and 4, which supports the center row of tips closer to the inner surface of the article. At the rear end of each wing W, as in Figs. 5 and 6, is formed a central boss 5I Within which combustible mixture tube 26 nts and around which cooling jacket 21 ts. Also, at the rear end of each Wing W, is a pair of outer bosses 52 within which cooling medium tubes 3| fit. Tube 26 and jacket 21 are secured to boss 5I, and tubes 3| are secured to bosses 52, in any suitable gas-tight manner, such as by welding, brazing, or silver-soldering.

Tips T, as in Fig. 5, are threaded into outlet passages 54, which are disposed in three parallel longitudinal rows and terminate in the outer surface of each wing. The central row of outlet passages in each wing extends centrally through platform 50, and each outlet in the center row leads from a central distributing passage extending longitudinally into the wing from the inlet at boss 5I, as in Fig. 6. Similarly, outlets 54 in each outer row lead from a distributing passage 56 extending longitudinally of the wing and connected with the inlet at boss 5| by a diagonal passage 51. The central distributing passage 55 and diagonal passages 51 may be drilled from the rear of each wing, while outer distributing passages 56 may be drilled from the front of each wing, and the open ends thereof closed by plugs 58, secured in place by welding, brazing, or in any other suitable manner. Also, a short transverse passage 59 may be drilled from the side of each wing into one of the passages 5B, so that the combustible mixture may be delivered to tip block K through a tube 60, one end of which is secured in passage 59. The other end of tube 6U is secured in an inlet passage 6I in block K, as in Figs. and 7, inlet passage 6l leading to a distributing passage 62 from which outlet passages 63 lead. Each of tips T' threadedly engages one of outlet passages 63, and, as indicated previously, is adapted to direct a high temperature heating flame against shoulder Il of coupling P.

To prevent overheating, a cooling medium is circulated longitudinally of each wing, between the rows of outlets 54 and as closeto the outer surface as possible. For this purpose, each wing is provided with four longitudinal cooling passages 645, as in Fig. 8, which conduct the cooling fluid from the inlets at bosses 52, or a cross passage 66 which connects the inlets with the two inner passages 65, to radially extending passages 61. As in Fig. 9, radial passages 61 lead directly into chamber 48, or into relatively short radial passages 63 which in turn lead into chamber 48. By cooling medium distribution passages provided as above, the cooling medium is circulated through each wing, from the rear to the front thereof and close to the outer surface which is directly exposed to heat. From the front of each wing, the cooling medium is discharged into chamber 48 in the interior of the device D, from whence it is conveyed by pipe 36, as previously described. The manner in which the cooling medium distributing passages are formed is optional, but in the embodiment illustrated herein, longitudinal passages 65 are drilled from the front of each wing, cross passages 66 are drilled from the side of each wing, and radial passages 51 and 6B are drilled from the top of each wing or the valley between adjoining wings. The open end of each of these passages is closed by a plug 69, which is secured in place by welding, brazing, or in any other suitable manner.

To prevent tip blocks K from becoming overheated, cooling medium is circulated therethrough by an inlet tube 1|, as in Fig. '7, which connects with one end of a passage 12 in block K, and an outlet tube 13, which connects with the opposite end of passage 12. Inlet tube 1| is connected with an outlet 14, drilled into one of the outer longitudinal passages 65 in each wing at a point spaced rearwardly of radial passages 61, as in Figs. 3, 8, and 9. Each outlet tube 13 discharges the cooling medium from the respec tive tip block K directly into one of radial passages 61, so that the distance between the points at which tubes 1I and 13 are connected to the cooling medium circulating passages in the wings results in a differential in pressure between the inlet and outlet tubes connected to each block Y K, and thus insures a steady flow of cooling medium through the blocks. The opposite ends of tubes 1| and 13 may be secured to the tip blocks K and the body of the device in any suitable manner, such as by brazing.

To harden inner surface portions of generally tubular metal articles by the apparatus of this invention, the carriage C is moved rearwardly, or to the right in Fig. l, so that the article to be treated, such as the coupling P, may be mounted in position for treatment. Common lever I8 may then be thrown to turn on the heating gases, the heating flames ignited, and the proportions of the combustion supporting gas or oxygen and the combustible gas or acetylene adjusted by regulating valves 24 and 25-a greater amount of oxygen than normal being used to compensate for a de- .will be supplied to tubes I2.

ciency of air inthe interior of the article, since in the open air suiicient oxygen is derived from the air to'support secondary combustion of* the heating flames. The cooling medium circulated through the device D and other portions ci the apparatus is also turned on, and after rotation of the article to be treated is started, the carriage C may be moved forwardly, or from left to right, to the position shown in Fig. 1. After a predetermined time interval of heating-Which may vary from 30 to 120 seconds, depending upon the size of the article and the depth of case to be produced-common lever I8 is thrown to turn oli? the heating gases and simultaneously therewith valve 40 opened so that the quenching medium As indicated previously, a relatively large amount of cooling medium is discharged into the interior of the article in a relatively short time, the heated surface portions thus literally being ilooded, and quenching is eifected in a relatively short time, such as 4a few seconds. The quenching medium may then be turned ofi", and the carriage C moved rearwardly to withdraw the device D from the interior of the article. The treated article can then be replaced by an untreated one and the operation repeated. For igniting the heating flames it may prove desirable to use a lighting blowpipe, burning a mixture of air and acetylene or other combustible gas, which may be passed quickly around .the device D. Also, it may prove desirable in some instances to insert the device D into the interior of the article before igniting the heating flames, as ames formed with an excess of oxygen sometimes tend to blow oi in the open air but will burn steadily in a confined space. The cooling medium circulated from header 3|] through the device D and other parts of the apparatus may be left on all the time.

From the foregoing, it will be evident that the apparatus of this invention can be used very effectively in llame hardening inner surface portions of generally tubular metal articles, because it is compact, is adequately cooled, and permits quenching to follow immediately after heating without any time delay. It will be obvious that tip block K can be removed in case it is not desired to harden shoulder Il, or the position of tips T and blocks 'K can be changed to treat other surface congurations.

It will be understood that various other changes may be made without departing from the spirit and scope of this invention, as defined in the appended claims.

What is claimed is:

l. Apparatus for llame hardening inner surface portions of a generally tubular metal article comprising a heating and quenching device having a body provided with a plurality of longitudinally extending wings spaced equally about the periphery thereof and a central chamber; at least one longitudinal row of heating flame outlets in each of said wings; passages formed in each of said wings for distributing a combustible mixture of gases to said outlets; separate passages formed in each of said wings for circulating a cooling medium through said wings from one end of said body to the opposite end thereof and thence into said central chamber; means for supplying a combustible mixture of gases to the distribution passages in said wings; means for supplying a cooling medium to the circulation passages in said wings; and means for withdrawing the cooling medium from said central chamber.

2. Apparatus for flame hardening inner surface portions of a female drill pipe coupling having threads and a shoulder for seating against the end of a male coupling, such apparatus comprising a, heating and quenching device provided with a plurality of longitudinal wings spaced equally about the periphery thereof; a plurality of longitudinal rows of tips extending outwardly from each of said wings and having outlets for directing heating ames against said threads; a block disposed between each adjoining pair of Wings at the forward end of said device and provided with a plurality of tips having outlets for directing heating flames against said shoulder; passages formed in each of said wings for distributing a combustible mixture of gasesl to said longitudinal rows of tips and also to said blocks; passages formed in said blocks for distributing a combustible mixture of gases to the tips thereof; separate passages formed in each of said wings for circulating a cooling medium through said wings from the rear to the forward end thereof; a central chamber formed in said device for conducting the cooling medium from the front to the rear end thereof; a quenching tube disposed in the space between each adjoining pair of wings and extending forwardly substantially to said blocks, each of said quenching tubes having outlets for discharging a quenching medium into the interior of said article and said outlets comprising longitudinal rows of slots spaced peripherally of said tubes and of suilicient size to discharge a relatively large amount of quenching medium into the interior of said article in a relatively short time; means for supporting said coupling for rotation about the longitudinal axis thereof; means for supplying a combustible mixture of gases to the distributing passages in said wings; means for supplying a cooling medium to the circulation passages in said wings; means for withdrawing cooling medium from said chamber at the rear end of said device; and means for supplying a quenching uid to said quenching tubes.

ROGERl o. DAY. HERBERT W. coWIN.

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