US2886692A - Constricted arc metal removal - Google Patents

Constricted arc metal removal Download PDF

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Publication number
US2886692A
US2886692A US586689A US58668956A US2886692A US 2886692 A US2886692 A US 2886692A US 586689 A US586689 A US 586689A US 58668956 A US58668956 A US 58668956A US 2886692 A US2886692 A US 2886692A
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United States
Prior art keywords
nitrogen
arc
hydrogen
cutting
gas
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Expired - Lifetime
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US586689A
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English (en)
Inventor
Glenn W Oyler
Iii John Maier
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Union Carbide Corp
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Union Carbide Corp
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Publication date
Application filed by Union Carbide Corp filed Critical Union Carbide Corp
Priority to US586689A priority Critical patent/US2886692A/en
Priority to ES0235635A priority patent/ES235635A1/es
Priority to FI0870/57A priority patent/FI40297B/fi
Application granted granted Critical
Publication of US2886692A publication Critical patent/US2886692A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • B23K10/00—Welding or cutting by means of a plasma

Definitions

  • This invention relates to metal removal with a constricted arc torch of the type disclosed by Robert M. Gage in his application, Serial No. 524,353, tiled July 26, 1955, now Patent No. 2,806,124, for Arc Torch and Process; and more particularly to the removal of non-ferrous metals and stainless steels with a high-pressure arc eluent composed of nitrogen alone or nitrogen mixed with hydrogen.
  • gas comprising essentially nitrogen is discharged through an annular space between a non-consumable electrode and the concentric inner wall of a water-cooled nozzle surrounding such electrode and into an arc constricting orifice from which such gas is discharged toward work composed of metal selected from the class consisting of non-ferrous metals and stainless steels which is connected in circuit ⁇ with a suitable source of electrical power for energizing an arc between the business end of such electrode and the work.
  • the resulting jet-like eiuent is used to scarf, gouge, pierce, cut, sever, or otherwise remove selected metal from such work as may be desired.
  • a remarkable advantage is that very low ow rates can be employed using nitrogen or mixtures containing predominantly nitrogen and still produce good quality cuts according to our invention. This is unexpected since, when using the conventional 35% hydrogen-65% argon mixture, the minimum flow is approximately twice that 'when using nitrogen. Flows of nitrogen as low as 25 cih. can be employed ⁇ without obtaining any deleterious effects. Nitrogen or nitrogen-hydrogen mixtures, which are reducing gases, seem to protect the cut surfaces from excess oxidation. Thus, under conditions in which good quality cuts are obtained, no post cutting preparation is necessary before Iwelding parts cut according to our process.
  • Another advantage of using nitrogen or nitrogen-hydrogen mixtures is the minimization of the double arcing phenomenon which is the preference of the arc to establish two independent arcs through the nozzle; the occurrence of which damages or destroys the nozzle. Since nitrogen and hydrogen have very high resistances, an 4insulating layer is apparently formed between the issuing arc and the inside of the metallic insert; which insulating layer retards the tendency of the arc to jump from the tungsten or copper electrode to the inner wall of the nozzle and then to the base plate.
  • the quality of the kerf walls in the arc torch cutting of stainless steel is improved using nitrogen over that normally obtained with argon, helium, or argonhydrogen mixtures.
  • Nitrogen or nitrogen-hydrogen mixtures which are reducing, protect the cut surfaces from excess oxidation by the air. Consequently, parts with such surfaces can be welded in the as-cut condition.
  • an arc torch 1 such as that of Patent No. 2,858,412 manually positioned above the metal work 2 to be cut, or supported by any suitable means, such as a conventional carriage (not shown).
  • Such torch comprises a tungsten electrode 3, the lower end of which is pointed and centrally located within the tapered inner annular wall 4 of a water-cooled copper nozzle insert 5 that can be readily removed and replaced.
  • Such nozzle insert has an ecological 6 through which the arc ⁇ and gas pass.
  • gas in this case nitrogen alone, or mixed with hydrogen gas, is delivered to the torch through a hose 7, from a owmeter t5 that is connected to ⁇ a gas supply line 9 by way of a main control box 1t).
  • the work 2 is connected to the positive (-1-) side of a D.C. power supply 11, through a lead 12, which is Iconnected to the positive side of a high frequency generator 13, and a lead 14 connecting the positive terminals of the HF generator and DC. power supply.
  • the negative side of the D.C. power supply 11 is connected to the electrode 3 through lead 15, contactor 16, lead 17, negative terminals of the HF generator 13, lead 18, main control box 1t?, and lead 19.
  • the contacter 16 is connected to the main control box by a main contactor cable 2t).
  • the D.C. power supply is also connected to the nozzle 5 of the farc torch through lead 14, high frequency generator 13, lead 21, through control box to lead 23, then through the torch-tonozzle insert 5.
  • a 115 volt A.C. control power supply cable 24 is also connected to the control box 10 and a 115 volt A.C. control power supply cable 24, water inlet and outlet pipes 25 and 26, and a remote control box 27 by cable 28.
  • Torch cooling water is conducted between the box and torch by a torch water inlet hose 29, and a water outlet hose 30, which also contains the torch power cable 19.
  • Our arc torch cutting employs an extremely high temperature, high Velocity, constricted arc 31 between the end of the tungsten electrode 3 and the piece 2 0f work to be cut.
  • the concentrated and columnated energy of the arc stream rapidly melts and ejects a thin section of metal to form a kerf 32.
  • Such jet-like action removes the molten metal and the gas atmosphere of the effluent prevents oxidation of the kerf walls.
  • the arc presently is constricted by using a nozzle insert 5 with a 1/8 in. or a 5/32 in. diameter opening.
  • An auxiliary circuit including leads 21 and 23, which is necessary for arcstarting, is used to connect the nozzle to the positive terminal of the power supply through a current limiting resistor 33 located on top of the box 10.
  • the high frequency unit is used with the pilot arc circuit to initiate the cutting arc.
  • the high frequency spark ionizes a path for pilot arc current between the electrode and the nozzle.
  • the ionized gas from the pilot are provides a low resistance path for the cutting current between the electrode and the work and the main cutting arc is initiated.
  • a pilot are maintained by high frequency is used to start the cutting arc.
  • the illumination provided by the pilot arc permits the operator to locate the edge of the plate at the d'esired point with his helmet in position.
  • the main arc is initiated.
  • the arc is extinguished and the nitrogen and/ or hydrogen stop flowing.
  • Good quality cuts have also been made using nitrogen on various thicknesses of copper. Quality cuts can be made at all speeds using nitrogen and there apparently is no minimum speed required as is the case with aluminum and magnesium. Good quality cuts can likewise be made with varying additions of hydrogen to the nitrogen/with comparable increase speeds as noted for magnesium and aluminum.
  • D.C.S.P. straight polarity
  • A.C. power supplies are also satisfactory for such purpose.
  • Process of cutting a body of metal selected from the class consisting of non-ferrous metals and stainless steels which comprises removing metal from such body by melting the metal to be removed to form a kerf in such body with a constricted electric arc comprising a jet of gas selected from the class consisting of nitrogen, and a mixture of nitrogen and a trace to 75% of hydrogen, which jet of gas carries an electric arc energized by current iiowing through a circuit that includes such body of metal characterized in that the so-cut metal is clean, smooth, and of excellent quality.
  • the improvement in the wall-stabilized arc-cutting process for removing metal from stainless steels and nonferrous metals or alloys by discharging a gas stream through an annular space between a non-consumable electrode and a concentric inner wall of a cooled nozzle and directing such stream about a high-pressure arc maintained at the end of the electrode in such gas characterized in that, to obtain cuts having smoother wall surfaces in the workpiece and to obtain a wider range of cutting speed, the gas is selected from the class consisting of nitrogen, and a mixture of nitrogen and hydrogen containing from 15% to 75 by volume of hydrogen.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Arc Welding In General (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
US586689A 1956-05-23 1956-05-23 Constricted arc metal removal Expired - Lifetime US2886692A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US586689A US2886692A (en) 1956-05-23 1956-05-23 Constricted arc metal removal
ES0235635A ES235635A1 (es) 1956-05-23 1957-05-22 UN PROCEDIMIENTO PARA LA REMOCIoN DE METAL DE ACEROS INOXIDABLES Y METALES NO FÉRREOS
FI0870/57A FI40297B (en:Method) 1956-05-23 1957-05-23

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US586689A US2886692A (en) 1956-05-23 1956-05-23 Constricted arc metal removal

Publications (1)

Publication Number Publication Date
US2886692A true US2886692A (en) 1959-05-12

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US586689A Expired - Lifetime US2886692A (en) 1956-05-23 1956-05-23 Constricted arc metal removal

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US (1) US2886692A (en:Method)
ES (1) ES235635A1 (en:Method)
FI (1) FI40297B (en:Method)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3140379A (en) * 1960-03-30 1964-07-07 United Aircraft Corp Method for forming modular electronic components
US3198932A (en) * 1962-03-30 1965-08-03 Union Carbide Corp Arc electrode
US3279177A (en) * 1963-06-10 1966-10-18 Giannini Scient Corp Apparatus and method for propelling vehicles in space
US3304719A (en) * 1964-07-28 1967-02-21 Giannini Scient Corp Apparatus and method for heating and accelerating gas
US3426172A (en) * 1965-10-24 1969-02-04 Texas Instruments Inc Method of welding a terminal tab to the plate of an electrochemical cell

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1002721A (en) * 1910-08-09 1911-09-05 Hub Machine Welding & Contracting Co Electric-arc furnace-heater.
US1746208A (en) * 1925-08-26 1930-02-04 Gen Electric Electric-arc cutting
US1746191A (en) * 1926-06-25 1930-02-04 Gen Electric Arc welding
US1746196A (en) * 1925-09-05 1930-02-04 Gen Electric Method and apparatus for electric-arc welding
US2063467A (en) * 1931-12-23 1936-12-08 Union Carbide & Carbon Corp Welding and cutting apparatus
US2474023A (en) * 1944-02-17 1949-06-21 British Thomson Houston Co Ltd Method of gas-shielded alternating current arc welding
US2479412A (en) * 1946-08-17 1949-08-16 Republic Steel Corp Cutting and cleaning of stainless steel billets
US2768279A (en) * 1955-01-18 1956-10-23 William A Mcdonald Electric arc torch apparatus
US2806124A (en) * 1955-07-26 1957-09-10 Union Carbide Corp Arc torch and process
US2821615A (en) * 1954-04-26 1958-01-28 British Oxygen Co Ltd Cutting of metals and alloys

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1002721A (en) * 1910-08-09 1911-09-05 Hub Machine Welding & Contracting Co Electric-arc furnace-heater.
US1746208A (en) * 1925-08-26 1930-02-04 Gen Electric Electric-arc cutting
US1746196A (en) * 1925-09-05 1930-02-04 Gen Electric Method and apparatus for electric-arc welding
US1746191A (en) * 1926-06-25 1930-02-04 Gen Electric Arc welding
US2063467A (en) * 1931-12-23 1936-12-08 Union Carbide & Carbon Corp Welding and cutting apparatus
US2474023A (en) * 1944-02-17 1949-06-21 British Thomson Houston Co Ltd Method of gas-shielded alternating current arc welding
US2479412A (en) * 1946-08-17 1949-08-16 Republic Steel Corp Cutting and cleaning of stainless steel billets
US2821615A (en) * 1954-04-26 1958-01-28 British Oxygen Co Ltd Cutting of metals and alloys
US2768279A (en) * 1955-01-18 1956-10-23 William A Mcdonald Electric arc torch apparatus
US2806124A (en) * 1955-07-26 1957-09-10 Union Carbide Corp Arc torch and process

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3140379A (en) * 1960-03-30 1964-07-07 United Aircraft Corp Method for forming modular electronic components
US3198932A (en) * 1962-03-30 1965-08-03 Union Carbide Corp Arc electrode
US3279177A (en) * 1963-06-10 1966-10-18 Giannini Scient Corp Apparatus and method for propelling vehicles in space
US3304719A (en) * 1964-07-28 1967-02-21 Giannini Scient Corp Apparatus and method for heating and accelerating gas
US3426172A (en) * 1965-10-24 1969-02-04 Texas Instruments Inc Method of welding a terminal tab to the plate of an electrochemical cell

Also Published As

Publication number Publication date
ES235635A1 (es) 1957-12-01
FI40297B (en:Method) 1968-09-02

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