US3774667A - Method and apparatus for manufacturing bent pipes - Google Patents

Method and apparatus for manufacturing bent pipes Download PDF

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Publication number
US3774667A
US3774667A US00152854A US3774667DA US3774667A US 3774667 A US3774667 A US 3774667A US 00152854 A US00152854 A US 00152854A US 3774667D A US3774667D A US 3774667DA US 3774667 A US3774667 A US 3774667A
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US
United States
Prior art keywords
bent pipe
curvature
bent
mold
radial side
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Expired - Lifetime
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US00152854A
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English (en)
Inventor
A Ujiie
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Mitsubishi Heavy Industries Ltd
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Mitsubishi Heavy Industries Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K25/00—Slag welding, i.e. using a heated layer or mass of powder, slag, or the like in contact with the material to be joined
    • B23K25/005—Welding for purposes other than joining, e.g. built-up welding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D23/00—Casting processes not provided for in groups B22D1/00 - B22D21/00
    • B22D23/06—Melting-down metal, e.g. metal particles, in the mould
    • B22D23/10—Electroslag casting
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/16—Remelting metals
    • C22B9/18—Electroslag remelting

Definitions

  • ABSTRACT [30] Foreign Application Priority Data A method Of manufacturing bent pipes which com- June 24, 1970 Japan 45/54354 prises melting plurality metal elecmdes fed a predetermined rate to an electroslag bath within a 52 US. 01 164/52, 164/85, 164 252 mold, allowing the molten metal thus formed to Solid 51 1111.111 B2241 27/02 ify ma ShaPe Conforming to the cross-Sectional [58] Field 61 Search 164/52, 85,252, and curvature of a desired bent P P thereby 164/231 forming a unitary bent pipe, and, at the same time, withdrawing said unitary bent pipe continuously along [56] Reterences Cited a curved path in agreement with the curvature of the UNITED STATES PATENTS desired bent pipe, and an apparatus adapted for the practice of the method.
  • This invention relates to a method of manufacturing bent pipes by melting metal electrodes fed to a mold in an electroslag bath therein, solidifying the molten metal in the mold, and continuously withdrawing the product from the mold to form a bent pipe with a desired curvature, and an apparatus for practicing the method.
  • Bent pipes with relatively high degrees of curvature such as 180 and 90 bends, have usually been made by forging or casting.
  • forging is adopted for the manufacture of such a bent pipe, it not only involves the use of expensive dies but produces a bent pipe with irregularity in the curvature along the surfaces of the inner and outer radii and ununiformity in the wall thickness.
  • the product is questionable in quality.
  • the pipe in the course of forging may develop cracks, fissures or other defects at its bent portion. Further, an increased degree of curvature or plastic working of the pipe could deteriorate the quality of the pipe material.
  • the reaction tube such as a reformer bent tube
  • the reaction tube is madegf such ahigl grade steel as HK40 which cannot be forged but cast, and therefore the products are used only after meticulous repair work because of the possibility of the above-mentioned defects.
  • the pipe material of this type has too poor weldability for complete correction work, and the products are frequent source of complaints.
  • the present invention has for an object to eliminate all the disadvantages of the conventional processes for producing bent pipes through adoption of unique technological means.
  • Another object of the present invention is to provide a unique method and apparatus which, taking advantage of the above-described straight-pipe manufacturing process, incorporates the same for the manufacture of bent pipes.
  • Still another object of the invention is to provide a method of manufacturing bent pipes by melting a plurality of metal electrodes fed at a predetermined rate in an electroslag bath within a mold, solidifying the resulting molten metal in said mold, and then continuously withdrawing the solidified metal at a predetermined rate from the mold, characterized in that the molten metal in the mold is caused to solidify to a shape conforming to the cross-sectional contour and curvature of the desired bent pipe, thereby forming a unitary bent pipe, and, at the same time, the unitary bent pipe is continuously withdrawn along a curved path in agreement with the curvature of the desired bent pipe.
  • a further object of the invention is to provide an apparatus for manufacturing bent pipes comprising an electrode assembly which consists of a plurality of metal electrodes with different cross-sectional areas arranged substantially equidistantly to conform to the overall cross-sectional contour of the bent pipe to be made, from the inner radial side toward the outer radial side of the bent pipe, in the order of increasing crosssectional area of the electrodes, said metal electrodes being adapted to be brought down by suitable drives at a predetermined speed, mold members consisting of an outer mold and a water-cooled core both disposed immediately below said electrode assembly and defining therebetween an annular channel which has a suitable width and a gradually increasing depth from the inner radial side toward the outer radial side of the bent pipe to be made and also an annular hole which, in communication with said annular channel, has a width equal to the wall thickness of the pipe to be made and a gradually increasing depth from the inner radial side toward the outer radial side of the bent pipe and has a curvature equal to the curvature
  • FIG. 1 is a schematic view, in vertical section
  • FIG. 2 is a schematic plan view illustrating the crosssectional shapes and arrangement of metal electrode.
  • the electrode assembly A consists of groups of metal electrodes A A A A and A A A A and rollers a a a a a a a (although only the rollers a and a, are shown in FIG. 1) which are driven by suitable drives (not shown) to bring down the electrodes at a predetermined speed.
  • the electrodes are arranged, as better shown in FIG. 2, vertically and at equal distances from each other in a formation corresponding to the cross sectional contour of the bent pipe to be made.
  • the crosssectional areas S, to S, and S, to S, of the metal electrodes A, to A, and A, to A,', respectively, are such that the cross-sectional areas 8,, S, of the metal electrodes A,, A, disposed on the side closest to the center of curvature of the bent pipe to be made are the smallest, and the cross-sectional areas 5,, S, of the metal electrodes A A, disposed on the side farthest from the center of curvature of the bent pipe to be formed are the largest.
  • the relations among these cross-sectional areas are S, S S S, and S, S S 8,, S 5,, and S, 8,.
  • Mold members B consist of an outer mold B, and a watercooled metal core 8,, both disposed immediately below the electrode assembly A. Between the outer mold B, and the core B is formed an annular channel W which is substantially funnel-shaped in vertical sec tion. In this annular channel W is formed a molten slag pool.
  • the mold members B are disposed in such a way that the lower ends of the metal electrodes A, to A A, to A, rest in the center of the upper section of the annular channel W.
  • the vertical sectional contours of the various portions of the annular channel'W are designed in consideration of the relations between the dimensions of the bent pipe to be made and the metal electrodes A, to A A, to A,.
  • annular hole Y In communication with the lower portion of the annular channel W there is defined an annular hole Y between the outer mold B, and the core B
  • the annular hole Y is so formed as to have the same cross-sectional contour and also the same curvature as those of the bent pipe to be made. It permits the formation of the pool of molten metal M by the electroslag melt phenomenon of the metal electrodes A, to A A, to A, in the annular channel W. At the same time, it permits solidification of the molten metal by the chilling action of the mold members B, so that a unitary bent pipe AP can be continuously formed.
  • the shape and dimensions of this annular hole Y are designed in conformity with the dimensions of the bent pipe to be made.
  • the symbol P designates a bent pipe with a wall thickness t to be made. Its curvature has an inner radius y, and an outer radius about an origin Q11;
  • the portions below the portions ee' f f and gg'hh are gradually expanded, while the portions above the portions ee f f have the same radius up to the point i where the radius of y, z from f intersects 0L and up to the point j where the radius of y; from hintersects 0L.
  • the portions above i, j and above e, g are gradually expanded so as to provide a suitable distance from the metal electrodes A, and A,.
  • the symbols 1, n, k, m indicate the points where the upper edge of the annular channel W intersects the line 5-8. The minimum distances from these points I, n, k, m to the metal electrodes A,, A, are the same.
  • the turnable members C for withdrawing the bent pipes consist of an arm K attached to a shaft perpendicular to the paper and passing the point 0, ta pi c att d. t satlarm Kansans,
  • the start piece p is shaped to a unit length of the same dimensions as the bent pipe P to be made. It is displaced along a path having the same curvature as that of the bent pipe to be formed by the turning of the motordriven arm K, thereby to withdraw the element AP of the bent pipe P from the mold members B.
  • the start piece p serves to close the bottom of the annular hole Y in the mold members B.
  • An electric system D consists of an electroslag power source E and a current-collecting board F. A terminal at one end of the power source E is connected to the arm K, while the other terminals are electrically connected to the metal electrodes A, to A, and A, to A, of the electrode assembly A through the current-collecting board F.
  • the resistance varies and the melting effect of the metal electrodes is increased by the difference of R in PR, with the result that the metal electrodes give a desired amount of melt in the annular hole Y.
  • the metal electrodes A, to A, and A, to A, of the electrode assembly A in a given position are fed at a predetermined rate by rollers and brought down at a constant speed with a current supplied to the currentcollecting board F.
  • the bottom of the annular hole Y isclosed beforehand with the start piece p, and suitable molten slag is held in the annular channel W.
  • the metal electrodes A to A and A, to A are immersed in molten slag pool, and these metal electrodes supply a current through the molten slag to the start piece p, thus forming an electric circuit for the power source E.
  • the apparatus of the present invention continuously manufactures a bent pipe with a desired curvature directly from the molten metal that is obtained by melting in an electroslag bath a plurality of metal electrodes fed at a predetermined velocity in the mold. Therefore, not only a bent pipe of a desired material can be easily and promptly made but also a bent pipe free from any defect and far superior in quality to the conventional products can be made to great advantage.
  • a method of manufacturing bent pipes which comprises the steps of feeding a plurality of metal electrodes to a mold at a predetermined rate and melting the same in an electroslag bath, solidifying the resulting molten metal to a size conforming to the desired crosssectional contour and curvature of the bent pipe to be formed, thereby forming a unitary bent pipe and, at the same time, continuously withdrawing said unitary bent pipe along a curved path in agreement with the curvature of said bent pipe, said steps being followed in a successive and sequential way, the plurality of metal electrodes being groups of metal electrodes having different cross-sectional areas, which are fed to the mold in an arrangement substantially at equal distances from one another and in the order of increasing crosssectional areas within the annular channel of the mold, the electrodes with small crosssectional areas being on the inner radial side of the curved portion of the bent pipe and the electrodes with larger cross-sectional areas on the outer radial side.
  • An apparatus for manufacturing bent pipes comprising an electrode assembly which consists of a plurality of metal electrodes with different cross-sectional areas arranged substantially equidistantly to conform to the overall cross-sectional contour of the bent pipe to be made, from the inner radial side toward the outer radial side of the bent pipe, in the order of increasing cross-sectional area of the electrodes, said metal electrodes being adapted to be brought down by suitable drives at a predetermined speed, mold members consisting of an outer mold and a water-cooled core both disposed immediately below said electrode assembly and defining therebetween an annular channel which has a suitable width and a gradually increasing depth from the inner radial side toward the outer radial side of the bent pipe to be made and also an annular hole which, in communication with said annular channel, has a width equal to the wall thickness of the pipe to be made and a gradually increasing depth from the inner radial side toward the outer radial side of the bent pipe and has a curvature equal to the curvature of said bent pipe, turnable members

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Manufacturing & Machinery (AREA)
  • Bending Of Plates, Rods, And Pipes (AREA)
  • Continuous Casting (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Furnace Details (AREA)
US00152854A 1970-06-24 1971-06-14 Method and apparatus for manufacturing bent pipes Expired - Lifetime US3774667A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45054354A JPS4840534B1 (no) 1970-06-24 1970-06-24

Publications (1)

Publication Number Publication Date
US3774667A true US3774667A (en) 1973-11-27

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ID=12968282

Family Applications (1)

Application Number Title Priority Date Filing Date
US00152854A Expired - Lifetime US3774667A (en) 1970-06-24 1971-06-14 Method and apparatus for manufacturing bent pipes

Country Status (13)

Country Link
US (1) US3774667A (no)
JP (1) JPS4840534B1 (no)
BE (1) BE768834A (no)
CA (1) CA928031A (no)
CS (1) CS182216B2 (no)
DE (1) DE2131891B2 (no)
DK (1) DK125629B (no)
FR (1) FR2096467B1 (no)
GB (1) GB1281810A (no)
NL (1) NL7108708A (no)
NO (1) NO134190C (no)
SE (1) SE375253B (no)
SU (1) SU462337A3 (no)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3910340A (en) * 1973-05-25 1975-10-07 Mitsubishi Heavy Ind Ltd Process and apparatus for producing bent tubes
US5048598A (en) * 1989-02-06 1991-09-17 Fujitsu Limited Reservior tank for a liquid cooling system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3910340A (en) * 1973-05-25 1975-10-07 Mitsubishi Heavy Ind Ltd Process and apparatus for producing bent tubes
US5048598A (en) * 1989-02-06 1991-09-17 Fujitsu Limited Reservior tank for a liquid cooling system

Also Published As

Publication number Publication date
DK125629B (da) 1973-03-19
NO134190B (no) 1976-05-24
CA928031A (en) 1973-06-12
SU462337A3 (ru) 1975-02-28
FR2096467B1 (no) 1974-03-22
DE2131891A1 (de) 1971-12-30
NO134190C (no) 1976-09-01
BE768834A (fr) 1971-11-03
CS182216B2 (en) 1978-04-28
FR2096467A1 (no) 1972-02-18
SE375253B (no) 1975-04-14
DE2131891B2 (de) 1975-02-06
GB1281810A (en) 1972-07-19
NL7108708A (no) 1971-12-28
JPS4840534B1 (no) 1973-12-01

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