US2532103A - Method and apparatus for thermochemically scarfing billets and the like - Google Patents

Description

Nov. 28, 1950 J. F. KIERNAN 2,532,103

METHOD AND APPARATUS FOR THERMOCHEMICALLY SCARFING BILLETS AND THE LIKE Filed April 1'7, 1947 5 Sheets-Sheet l J. F. KIERNAN METHOD AND APPARATUS FOR THERMOCHEMICALLY SCARF'ING BILLETS AND THE LIKE Nov. 28, 1950 3 Sheets-Sheet 2 Filed April 17, 1947 INVENTOR jlfz W BY 4%,; M, AZV 29 ATTORNEYX Nov. 28, 1950 J. F. KIERNAN METHOD AND APPARATUS FOR THERMOCHEMICALLY SCARFING BILLETS AND THE LIKE C5 Sheets-Sheet 3 Filed April 17, 1947 IFE INVENTOR BY ,A zwwg 4.1 AWL,

' ATTORNEY-f jets there are regions between them that have relatively low oxygen density. Preferably both the upper and lower portions of the jets are baffled, but even when only the upper portions of the jets are bafiled a substantial improvement can be obtained in the smoothnes of the scarfed surface over prior practices. The baffling may'be eiiected by passing the individual oxygen jets between upper and lower baflie plates, or baffling portions on the tip structure, which form a slotlike opening that converts the-individual jets into the desired sheet-like stream. The extent to which the jets should be bafiied will depend upon various circumstances, but when the passages from which the jets issue are of circular crosssection the baiiling of the upper portion of the jets will in most cases not have to exceed that amount which is obtained when the upper baffle overlaps the discharge orifices of the jet passages approximately one-third of the radius of the discharge orifices, and the same true of the baiiiing of the lower portion of the jets. The bailiing of the oxygen jets regardless of their cross-sectional shape is eifected preferably after the oxygen jets have expanded practically to atmospheric pressure, or have at least expanded a substantial amount after leaving their discharge orifices. Too great a degree of baffling, or premature baffling; tends to cause the jets to spray-out and establish conditions that are undesirable so far as the contemplated results are concerned. The effect of the 'bafliing is to displace the oxygen that forms the upper and lower crests of the jets and to fill the spaces'between adjacent jets by such displaced oxygen to thereby produce a sheet-like oxygen stream in which the oxygen is substantially uniform in density throughout an extent of the oxygen'stream which corresponds to the width of the work area being scarfed.

I. The improved method and apparatus adapted for use incarrying-it out are illustrated in the accompanying-drawings, in which: a

' 'Figures 1-3 illustrate the principle of the invention, both as to the method and the appara- 'tus, Figure 1 being a broken perspective view of a "simple form of block-type torch tip, minus the usual means for preheating the surface metal of the work-piece to kindling temperature, but provided with baiiles for bafiiing the scarfing oxygen jets-in accordance with the method, and Figures 2 and 3 being explanatory views illustrating the action of the baffles on the oxygen jets;

Fig. l is a-perspective view, partly in section, of a block-type tip structure complete with means for preheating-the surface metal of the work- -'piece to kindling temperature and'that is adapted for use in carrying out the method;

Fig.5 is a side elevation of the torch tip shown inFig l;

Fig. 6 is a'vertical longitudinal section through "the torch tip shown in Fig.4; 1 Fig'. '7 atransverse section taken on m5 line '1 of Fig. 6; a e

Fig. 3 is a top plan view of the torch tip shown finFigA; I; Fig. 9is a plan view of the shoe that forms one 1 section of the torch tip shown in Fig. 4 but drawn to a smaller scale;

. Fig. 10 is a plan view, partly in section, of the preheat section of the torch tip shown in Fig. 4

but drawn to a smaller scale; and f Fig. 11 is a plan View, partly in section, of the scarfing section of the torch tip shown in Fig. 4 but drawn to a smaller scale.

Referring first toFigure 1, a torch tipof the 4 block type is represented at I. It has a nose portion formed by upper and lower sloping faces 2 and 3 which converge toward a front face 4 that constitutes the discharge face of the tip. Scarfing oxygen is delivered to the tip through an inlet pipe 5 and is distributed to anumbr of jet passages in the tip in a manner well'understood in the art. The jet passages terminate in a row of discharge orifices 6 in the discharge face 4. The scarfing oxygen issues from these discharge orifices as individual oxygen jets one of which is represented at I. The simple form of torch tip illustrated in Figure 1 has no provision for heating the surface metal of the work-piece to kindling temperature and therefore in the form shown would not be suitable for carrying out a scarfing operation- However it can be assumed that the surface metal of the billet or other workpiece to be scarfed, and represented at W, is heated to kindling temperature by any suitable preheating means positioned above the tip and arranged to project preheating flames against the surface of the work-piece above the upper baflle 8. The torch tip is supported so that the oxygen jets will be directed angularly against the surface of the work-piece as shown, and when the workpiece is moved under the torch tip in a direction opposite to that in which the oxygen jets are directed, or the torch tip i moved along the workpiece in the same direction as that in which the oxygen jets are directed, the surface metal will be progressively removed from the Work-piece thermo-chemically. as is well understood in the art.

In accordance with the invention the torch tip is provided with a baiile 8 for baffling the upper portion of the oxygen jets I, and preferably also with a lower baflie 9 for similarly baiiling the lower portion of the jets. The upper baffie is attached to the upper sloping face 2 of the torch tip and the lower bafiie is secured to the lower sloping face 3 of the torch tip. The upper baffle isadjustably connected to the tip so that it can be adjusted to vary the extent to which it projects beyond the discharge face 4 of the tip by any suitable means such as bolt and slot connections shown at IG. The lower baffle may also be adjustably connected to the torch tip in a similar manner. The bailies project beyond the discharge face 4 far enough so that their edges form a slot-like opening through which the oxygen jets pass after they have expanded practically to atmospheric pressure. The expansion of the jets to substantially atmospheric pressure is represented in Fig. l by the diverging character of the jets prior to the time'they reach the edges of the two baiiles. As previously stated the baffles displace oxygen from the upper and lower por tions of the jets and cause the displaced oxygen to fill the voids between adjacent jets so that after the oxygen leaves the slot-like opening be tween the edges of the bailies'it is in the form of a sheet in which the oxygen is substantially uniform in density in all parts of the stream.v

The effect that the baflies have on the oxygen jets isrepresented diagrammatically in Figs. 2 and 3. The dark areas shown at l l in Fig. represent the discharge orifices in the torch tip where the scarfing oxygen is still inits compressed state. The lighter surrounding regions shown at'lZ represent the less dense oxygen in the jets during and after the expansion of the jets. It is'evident that without any battling the oxygen jets tend to retain their individual character rather than blend or minslewithadjacent jetl's and: this. causes ridges to be" left. on the! eachof the'jets by the upper'bafileandthe'oxygen displaced from the lower portion I'E'of eachiof the jets by the lower bafiie will thenTbecaused' to fill the; spaces betweenthe oxygen jet's'; Thus thejets are mingled by: the baflies into a sheet-- like stream in which the oxygen. is substantially" uni-for'm in; density. throughout" the stream as" represented in Fig- 3.

Figs. i -l1} inclusive. illustrate a somewhat more elaborate torch tip emb'odyingthe inventionand adapted for usein-carrying. out'the improved meth odi- The torch tip shown in" these fig-ui'es is-also of the block type but the tip block is a composite one made up of three principal sections, namely, a scarfing. section having a discharge face from which the scarfing oxygen jets issue, a shoe section below the scarfing section, and apreheatsection above the scarfing section adapted'to direct preheating flames against the work to bring. the surface metal to kindling temperature. fhe. shoe section andthe preheat section have edge portions which project beyond the discharge face of the scariing section to form baffies corresponding. to the bafiies previously described.

Referring first to Fig. 4, the torch tip in its entiretyv is designated 29. It is shown in scarfing relationto a billet or work-piece W. The torch tipis secured to a supporting structure, not shown. by threaded studs 2|.

The scarfing section of. the tip is shown at 22. Scarfing oxygen is delivered to and passes through this section of the tip by the means hereinafter described and issues from its discharge face 22"'as a. series of individual oxygen jets.

The preheat section'is shown at 24. A comb'ustible gas mixture delivered to the preheat section. 2! issues from a row of discharge orifices in its discharge face 24' and when'ignited produces a row of preheating flames some of'which are shown at 25. The preheat section is secured to the scarfing section by bolts 26'.

The shoe section is shown at 21. It is secured to the scarring. section by means of bolts 28. Plates 2 9 welded along their lower edge portions to the end faces of the shoe section are secured to the side faces of the scarfing section by bolts and thereby support the forward portion of the shoe section. Only one of these plates appears in Fig. 4 but both of them are shown in Fig. 8. h

The preheat section 24'rests on the upper surfaces 31 and 3! of the scarfing section as shown in Fig. 6. It is capable of liinited'forward and rearward'adjustment on these surfaces. To permit this adjustment the stem portions of the bolts 26 pass through slots 32 (Fig. '8) in the preheat section and the head portions of the bolts are received by larger slots 32'. At the bottom of the larger slots there is a shoulder 34 (Figs. 5 and 83 with which the bolt heads cooperate in clamping the preheat section to the scarfing' sec tion. The position of" the shoulders is such that the tops of the bolts 26 lie substantially flush with the top surface of the preheat section as best shown in Fig. 4.

The preheat section 24 is provided with an inlet connection 35 (Figs. 5 and 6) having a The " does not show central passage 35" forfthe preheat oxygen.- The end of the inlet connection istapered-onconical as shown at 3'7 and isprovidedwith'an -annular recess 38'. from which a number 'ofdiagonalpassages 39 lead to the" central oxygenpassage-136i The inlet connection is also provided" with-a number of cooling water passages 40 surround"'-- ing the central oxygen passage 3 6 and" having'i inlet openings 48 in the conical surface 31 of the inlet connection. The conical endof the" inlet connection is adapted tobe clamped by means of a nut 4| in a conical seat in a head that formspart of gas and water supply means *(not shown) and having suitable supply passages'for supplyingpreheat oxygen tothe cerrral passage 36,

passages as. The fuel-gas supplied to the annular' recess 38 passes through the d'iagonal pas sages 3S and mixes with the preheat oxygenin-- the central passage 36" to form a" combustible gas mixture which isdelivered by" means of a passage 42 in the preheat section to a distribut-' ing'chamber 43 (Figs; 6 and 10) which extends longitudinally of the preheat'section. The gas mixture" passes from this chamber through a" number of passages 44 into a seconddistributin'g chamber as.

her of passages 46 to a third distributing'chamber ail. hire to the jet. passages 48" which deliver itto the discharge face 24" of the preheat section where it issues as a row of jets which,. when ignite'd, produce the preheating. fiam'es'25 (Fig 4)".

The cooling water supplied to the passages: ii in the inlet connection passes into an' annular chamber 49 in the preheat section (Fig; 67', then into a passage fiil'which conducts it toward the forward end of the preheat section to a 1ongitudinal passage 5! (Fig; 10). This passage conducts the cooling water toward the right end of the preheat section as? viewed" in Fig. 10 where a connecting passage (which in Fig. 10) delivers it to another longitudinal passage 52 which conducts it to the opposite end of the tip. The cooling water then passes through a connecting. passage 53-, similar to the connectingpassage. at the right end of the preheat section, to a return longitu dinal passage 54, then through passages 55 and 5b to a discharge tube 51. Of course, any other suitable arrangement of cooli'ng passages could be used.

Scarfing oxygen is supplied to the scarfing section 22 through an inlet nipple 58' (Fig. 6'). It first passes into a longitudinal distributing chamber 59 (Figs. 6 and 11), then into a second longitudinal distributing chamber 66 through a series of passages 55, and then into a third longitudinal distributing chamber 62 through a series of passages 63. The three distributing chambers 59, 68 and 62' are preferably successively smaller in cross-sectional area; The third distributing chamber 62 distributes the sc'arfing oxygen to a row of jet passages 64 which deliver it to the discharge face 22" of the scarfing section from which it issues as the previously de scribed scarfing jets.

The scarfing section is also preferabl provided with a cooling system which may comprise an arrangement of cooling water passages similar to that used in the preheat'section. As-best shown in Fig; 11, cooling water is introduced 7 through'aninlet connection -65 and then passes acetylene or'other' fuel-gasto the annular recess 38*, and cooling water'to the From the second distributing chamber'the gas mixture passes through a num This chamber distributes'the" gas mix :angles to the longitudinal passages. sage Tl communicates at its rear end with a water inlet tube 86.

l successiveiy through passages 66, 61, 68, 69 and to an outlet connection I I.

Attached to the underside of the shoe 2! is a plate 12 (Fig. 6) made of wear-resistant material. It extends longitudinally along the forward edge portion of the shoe and is secured in place in any suitable way as by means of the rivets 13. The plate rides on the surface of the work-piece and protects the other parts of the torch tip from wear.

The shoe section may also be provided with a cooling system, if desired, formed by any suitable arrangement of cooling water passages.

Fig. 9 shows one arrangement that may be em- This passage intersects all three of the longitudinal passages. The passage i8 is plugged at its rear end and intersects only two of the longitudinal passages, namely, passages 74 and E5. The passage '59 communicates at its rear end with an outlet tube 3! and intersects all three of the longitudinal pas- .sages, but a plug 82 closes off the passage is at a point between the longitudinal passages '54 and 15. A plug 83 closes off the longitudinal passage 14 at a point between the inlet passage 1'! and the adjacent passage is, and a plug as similarly closes ofi the longitudinal passage 55 at a point between the passages I1 and 18. There is thus provided a tortuous and continuous path through the shoe for the cooling water as follows: inlet Bil, passage ll, passage 16, forward portion of passage 79, passage 15 as far as the plug 84, passage '58, that part of passage '14 to the left of plug 83, and the rear portion of passage 19 to the outlet 8 i.

As best shown in Figs. 5 and 6 a portion of the preheat section projects forwardly beyond the discharge face 22 of the scarfing section to provide a projecting lip 85, and a portion of the shoe section similarly projects forwardly beyond the discharge face of the scarfing section to provide a projecting lip 36. The edges of these two lips correspond to the forward edges of the baffle plates described in connection with Fig. l and act on the oxygen scarfing jets issuing from the jet passages 54 to produce the result hereinbefore described. The bafliing eifect that the edges of the projecting lips 85 and 83 have on the scarfing jets may be varied by adjusting the preheat section forwardly or rearwardly on the scarfing section and also, if necessary, by replacing the shoe section with another one having a lip 86 which projects a greater or lesser distance beyond the discharge face of the scarfing section.

While the bafliing effect is preferably obtained in a three piece composite torch tip of the kind shown in Figs. 4-11 by integral portions of the preheat section and the shoe section which project forwardly beyond the discharge face of the scarfing section, as above described, it may be obtained if desired by plates or shims inserted between the three sections of the tip and projecting forwardly beyond the discharge face of the scarfing section.

The preheating flame jets are preferably directed toward substantially the same area of the work surface as the oxygen scarfing jets. Adjustment of the preheat section to vary its bafiiing The paseffect on the scarfing oxygen jets does notchange this condition because the adjustment of the preheat section does not alter the angular relationship between the preheating flame jets and the scarfing jets. Moreover, it will be observed that baffling of the oxygen scarfing jets by the projecting portion of the preheat section is accomplished without in any way interfering with the preheating flame jets since they issue from a discharge face which lies above the bafliing edge on the preheat section.

The provision of two baffles is not always necessary. In some cases a single baffle acting only on the upper portions of the oxygen scarfing jets and mingling them into a more sheet-like form may be sufiicient to produce a scarfed surface on the work-piece having the desired degree of smoothness.

The turbulence produced in the oxygen scarfing jets by the baffle or baflles gives better heat distribution throughout the oxygen stream due principally to the fact that the oxygen stream is already turbulent when it comes under the heating infiuence of the preheating flames. This also contributes toward smoother scarfing.

Not only does the invention make it possible to obtain a smoother scarfed surface on the workpiece than heretofore but it effects a considerable saving in the consumption of scarfing oxygen.

I claim:

1. Apparatus for scarfing metal bodies comprising a torch tip structure having a plurality of scarfing oxygen jet passages terminating in a row of discharge orifices, means for supplying scarfing oxygen to said jet passages for issuance from said discharge orifices as a row of scarfing jets, and bafiiing means common to all of the jets of said row and acting on the jets forwardly of said discharge orifices to mingle the jets into a more sheet-like form.

2. Apparatus for scarfing metal bodies comprising a torch tip of the block type having a discharge face and having a plurality of scarfing oxygen jet passages drilled into the block and terminating in a row of discharge orifices in said discharge face, and means for supplying scarfing oxygen to said jet passages for issuance from said discharge orifices as a row of scarring jets, said tip having bafiling means common to all of the jets of said row and acting on the jets forwardly of said discharge orifices to mingle the jets into a more sheet-like form.

3. Apparatus for scarfing metal bodies comprising a torch tip structure having a plurality of scarfing oxygen jet passages terminating in a row of discharge orifices, means for supplying scarfing oxygen to said jet passages for issuance from said discharge orifices as a row of scarfing jets, and means extending throughout the length of said row of discharge orifices and-positioned at least partially in the path of jets of scarfing oxygen issuing from said discharge orifices and forming a slot-like opening located forwardly of said discharge orifices at such a distance and having such width that the scarfing jets pass through said opening after they have expanded a sub stantial amount after leaving the discharge orifices and are thereby converted into a sheetlike stream of oxygen in which the oxygen is substantially uniform in density throughout an extent of the oxygen stream which corresponds to the width of the work area being scarfed.

4. Apparatus for scarfing metal bodies comprising a torch tip having a scarfing section and a preheatsection above the scarfing section, the scarfing section having a discharge face and a plurality of jet passages terminating ina-rowof discharge orifices -in said discharge face and fur- =ther having-meansfor supplying scarfing oxygen to said jet passages --for issuance from said dis- --charge oriflces-as-a row =of scarfing jets, saidpre- "heat section having a discharge face an'di-al plu- 'rality of jet passages terminating in a row-.of iiis- =charge orifices -in-the-discharge face and fui ther having means for supplying a combustible gas mixture to the jet passages for issuance from the discharge orfices as a row of jets of combustible gas which when ignited produce a row of preheating flames, and the preheat section having a portion which projects forwardly beyond the discharge face of the scarfing section an edge of which is adapted to be engaged by the oxygen scarfing jets after they have expanded a substantial amount to mingle them into a more sheet-like form.

5. Apparatus for scarfing metal bodies in accordance with claim 4 in which the jet passages in the scarfing section and those in the preheat section lie in planes which intersect substantially at the work surface.

6. Apparatus for scarfing metal bodies-in accordance with claim 5 having means by which the preheat section is adjustable on the scarfing section substantially in the plane of the preheat jet passages.

7. Apparatus for scarfing metal bodies including a torch tip comprising a scarfing section provided with a discharge face and having means for projecting a row of individual jets of scarfing oxygen from such discharge face at an angle to the work surface, and a preheat section located above the scarfing section and having means for projecting preheating flames at an angle against the work surface, said preheat section having a portion which projects forwardly beyond the discharge face of the scarfing section and which is adapted to be engaged by the scarfing jets after they have expanded a substantial amount to mingle them into a more sheet-like form.

8. Apparatus for scarfing metal bodies including a torch tip comprising a scarfing section provided with a discharge face and having means for projecting a row of individual jets of scarfing oxygen from such discharge face at an angle to the work surface, a preheat section located above the scarfing section and having means for projecting preheating flames at an angle against the work surface, and a shoe for supporting the scarfing section on the work, the preheat section and the shoe having portions projecting forwardly beyond the discharge face of the preheat section and which are arranged to be engaged by the scarfing oxygen jets after they have expanded a substantial amount to convert them into a sheet-like stream of oxygen.

9. Apparatus for scarfing metal bodies including a torch tip comprising a scarfing section having a discharge face and means for projecting a row of oxygen scarfing jets from such discharge face at an angle to the work surface, said means including jet passages arranged in a plane in clined with respect to the work surface, a preheat section above the scarfing section and having means for projecting preheating flames at an angle to the work surface, said last-named means including jet passages arranged in a plane inclined with respect to the work surface so that the preheating flames impinge on the work surface substantially at the same region as the scarfing jets, sa d preheat section having a portion which iprojectsfiorwardly of the discharge fface on the scarfing section "and which 'acts on the soarfin'gijets after theyhave expanded asubstantial amount "to mingle "them into a more sheet-like 'form, and said "preheat section *being adjustable on the scarfing section substantially in theiplane of thepreheat jet passages.

10. Apparatu's'for scarfing metal bodies comprising a torch tipistructure having a plurality of scarfing oxygen jet passages'terminating in a "row of discharge orifices, means for supplying scarfing oxygen to said jet passages' for issuance from such discharge orifices as a row of scarfing jets, and a bafiie common to all of the jets of said row and acting on the jets forwardly of said discharge orifices to mingle the jets into a more sheet-like form, the baffle being adjustable forwardly and rearwardly to vary the extent of the baffling action of the baiiie on the jets.

11. Apparatus for scarfing metal bodies comprising a torch tip structure having a plurality of scarfing oxygen jet passages terminating in a row of discharge orifices, means for supplying scarfing oxygen to said jet passages for issuance from said discharge orifices as a row of scarfing jets, and means extending throughout the length of said row of discharge orifices and positioned at least partially in the path of jets of scarfing oxygen issuing from said discharge orifices and forming a slot-like opening located forwardly of said discharge orifices and through which all of the oxygen jets pass and which acts on the jets to mingle them into a more sheet-like form.

12. The method of scarfing metal bodies which comprises projecting flame jets against the surface of the work to heat the surface metal to kindling temperature, discharging oxygen from a row of discharge orifices to produce a row of individual oxygen jets and directing said oxygen jets toward the surface of the work while the surface metal is at kindling temperature, and in addition to any action which the flame jets may have on the oxygen jets baffling the oxygen jets after the oxygen forming them leaves the discharge orifices and before the oxygen jets impinge on the surface of the Work to mingle the oxygen jets into a more sheet-like form.

13. The method of scarfing metal bodies which comprises projecting flame jets against the surface of the work to heat the surface metal to kindling temperature, discharging oxygen from a row of circular discharge orifices to produce a row of individual oxygen jets which are initially of circular cross-section and directing said oxygen jets toward the surface of the work while the surface metal is at kindling temperature, and in addition to any action which the flame jets may have on the oxygen jets baffling the upper portion of the oxygen jets after they leave the discharge orifices and before the oxygen jets impinge on the surface of the work to mingle the oxygen jets into a more sheet-like form.

14. The method of scarfing metal bodies which comprises projecting flame jets against the surface of the work to heat the surface metal to kindling temperature, discharging oxygen from a row of circular discharge orifices to produce a row of individual oxygen jets which are initially of circular cross-section and directing said oxygen jets toward the surface of the work while the surface metal is at kindling temperature, and in addition to any action which the flame jets may have on the oxygen jets baliling the upper and lower portions of the oxygen jets after they 1 1 leave the discharge orifices and before the oxygen jets impinge on the surface of the work to convert the oxygen jets into a flattened sheet in which the oxygen is substantially uniform in density throughout an extent of the oxygen sheet which corresponds to the width of the work area being scarfed.

JOSEPH F. KIERNAN.

REFERENCES CITED Number "12 UNITED STATES PATENTS Name Date Lausen July 10, 1928 Rendleman Oct. 20, 1936 Scheller July 21,1942 Walker et a1 -May 2, 1944 Barnes et a1 Aug. 22, 1944 Jones et al Aug. 22, 1944 Crowe Apr. 23, 1946

Claims (1)

12. THE METHOD OF SCARFING METAL BODIES WHICH COMPRISES PROJECTING FLAME JETS AGAINST THE SURFACE OF THE WORK TO HEAT THE SURFACE METAL TO KINDLING TEMPERATURE, DISCHARGING OXYGEN FROM A ROW OF DISCHARGE ORIFICES TO PRODUCE A ROW OF INDIVIDUAL OXYGEN JETS AND DIRECTING SAID OXYGEN JETS TOWARD THE SURFACE OF THE WORK WHILE THE SURFACE METAL IS AT KINDLING TEMPERATURE, AND IN ADDITION TO ANY ACTION WHICH THE FLAME JETS MAY HAVE ON THE OXYGEN JETS BAFFLING THE OXYGEN JETS AFTER THE OXYGEN FORMING THEM LEAVES THE DISCHARGE ORIFICES AND BEFORE THE OXYGEN JETS IMPINGE ON THE SURFACE OF THE WORK TO MINGLE THE OXYGEN JETS INTO A MORE SHEET-LIKE FORM.

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