Air Carbon-Arc Guide - Rapid Welding
Air Carbon-ArcGuideRevision: BIssue Date: November 4, 2010Form No: 89-250-008
YOU ARE IN GOODCOMPANY!The Brand of Choice for Contractors and FabricatorsWorldwide.Arcair is a Global Brand of Welding Products forThermadyne Industries Inc. We manufacture andsupply to major welding industry sectors worldwide,including: Manufacturing, Construction, Mining,Automotive, Aerospace, Engineering, Rural andDIY/Hobbyist.We distinguish ourselves from our competitionthrough market-leading, dependable products thathave stood the test of time. We pride ourselves ontechnical innovation, competitive prices, excellentdelivery, superior customer service and technicalsupport, together with excellence in sales andmarketing expertise.Above all, we are committed to developtechnologically advanced products to achieve a saferworking environment within the welding industry.i
AIR CARBON-ARC GUIDEWARNINGRead and understand this entire Guide and your employer’s safety practicesbefore installing, operating, or servicing the equipment. While the informationcontained in this Guide represents the Manufacturer’s best judgement, theManufacturer assumes no liability for its use.Air Carbon-Arc GuideForm Number: 89-250-008Published by:Thermadyne Industries, Inc.2800 Airport RoadDenton, Texas 76208(940) 566-2000www.thermadyne.comCopyright 2010 by Thermadyne Industries, Inc. All rights reserved.Reproduction of this work, in whole or in part, without written permission of thepublisher is prohibited.The publisher does not assume and hereby disclaims any liability to any party for anyloss or damage caused by any error or omission in this manual, whether such errorresults from negligence, accident, or any other cause.Publication Date: November 4, 2010ii89-250-008
AIR CARBON-ARC GUIDETable of ContentsSECTION 1: INTRODUCTION. 1-41.01Process Description. 1-41.02History. 1-41.03Applications. 1-5SECTION 2: SAFETY AND HEALTH. 2-6SECTION 3: PRINCIPLES OF OPERATION. 3-12SECTION 4: OPERATING TECHNIQUES. 4-18SECTION 5: EQUIPMENT SELECTION. 5-26SECTION 6: IMPORTANT PROCESS VARIABLES. 6-29SECTION 7: ADVANTAGES. 7-34SECTION 8: APPLICATIONS AND TROUBLESHOOTING. 8-3589-250-008iii
AIR CARBON-ARC GUIDESECTION 1:INTRODUCTION1.01PROCESS DESCRIPTIONThe air carbon-arc process (CAC-A) physically removes metal, not chemically asin oxy-fuel cutting (OFC). Gouging or cutting occurs when the intense heat of thearc between the carbon electrode and the workpiece melts part of the workpiece.Simultaneously, air passes through the arc quickly enough to blow the moltenmaterial away.The air carbon-arc process does not require oxidation to maintain the cut, so itcan gouge or cut metals that the OFC process cannot. Most common metals (e.g.,carbon steel, stainless steel, many copper alloys and cast irons) can be cut usingthe air carbon-arc process. The metal removal rate depends on the melting rateand the air jet’s efficiency in removing molten metal. In the process, the air mustlift the molten metal clear of the arc before the metal solidifies.1.02HISTORYAir carbon-arc gouging began in the 1940s, evolving from the existing carbon-arccutting process. Myron Stepath, a welding engineer, developed air carbon-arcgouging to remove several hundred feet of flat, cracked, stainless steel weld.Previously, carbon-arc cutting removed overhead and vertical defective weldsand rivet heads. The carbon-arc melted the metal, then gravity moved the moltenmetal away.Stepath reasoned that an air jet could provide the force to remove metal laying flat.So a direct-current, electrode-negative carbon-arc was tried with a second operatordirecting an air blast via air nozzle at the molten pool. However, this attempt wasunsuccessful because the arc was more unstable than a carbon-welding arc.So, Stepath tried a direct-current, electrode-positive arc and the result was aircarbon-arc gouging.Introduction1-489-250-008
AIR CARBON-ARC GUIDEIn 1948, Myron Stepath introduced the first air carbon-arc torch to the weldingindustry. In 1949, Stepath and two associates founded the Arcair Company.Now, two operators were not needed. The compressed air passed through the torchand exited beneath the electrode. This new tool saved time on weld backgouging,crack removal, and weld defect repair on carbon, alloy, and stainless steel.Previously, these tasks were performed by grinding or chipping. The basic principleremains the same today, but with improved equipment and an expanded numberof applications.1.03APPLICATIONSThe industry has enthusiastically adopted air carbon-arc gouging and found manyuses for the process in metal fabrication and casting finishing, chemical andpetroleum technology, construction, mining, general repair, and maintenance.Arcair Torches and Electrodes are used throughout the world, anywhere metal isgouged, grooved, severed, or removed from a surface.The air carbon-arc process is flexible, efficient, and cost effective on practically anymetal: carbon steel, stainless steel and other ferrous alloys; gray, malleable andductile iron; aluminum; nickel; copper alloys and other nonferrous metals.89-250-0081-5Introduction
AIR CARBON-ARC GUIDESECTION 2:SAFETY AND HEALTHSafe practices in welding and cutting processes, such as air carbon-arc, is covered inANSl Z49.1, “Safety in Welding and Cutting”, and ANSl 249.2, “Fire Prevention in Useof Welding and Cutting Processes.” Air carbon-arc operators and their supervisorsshould adhere to the safe practices discussed in these documents.Other hazards in arc welding and cutting are briefly discussed in this section.Proper Installation, Use, and MaintenanceSerious injury or death may result if gouging and cutting equipment is not properlyinstalled, used, and maintained. Misuse of this equipment and other unsafe practicescan be hazardous. The operator, supervisor, and helper must read and understandthe following safety warnings and instructions before installing or using any aircarbon-arc torch or equipment.The gouging/cutting process is used in many potentially dangerous environmentssuch as elevated heights, areas of limited ventilation, close quarters, around water,in hostile environments, etc., and it is important that the operators are aware of thedangers associated in working in these types of conditions. The operator(s) mustbe trained in safe practices for their work environments and under competentsupervision.It is essential that the operator, supervisor, and others in the work area are awareof the dangers of the air carbon-arc process. Training and proper supervision areimportant for a safe work place. Keep these instructions for future use. Additionalrecommended safety and operating information is referenced in each section.ELECTRIC SHOCK CAN CAUSE INJURY OR DEATHInstall and maintain equipment in accordance with the NationalElectrical Code (NFPA 70) and local codes. Do not service or repairequipment with power on. Do not operate equipment with protectiveinsulators or covers removed. Service or repair to equipment mustbe done by qualified and/or trained personnel only.Safety and Health2-689-250-008
AIR CARBON-ARC GUIDEElectrodesKeep carbon electrodes dry. If electrodes become damp, bake them for 10 hoursat 300 F (176 C). Wet electrodes may shatter.Do not contact electrically live parts. Do not touch electrode with bare skin andelectrical ground at the same time. Always wear dry welding gloves in goodcondition. Aluminized protective clothing can become part of the electrical path.Keep oxygen cylinders, chains, wire ropes, cranes, hoists. and elevators away fromany part of the electrical circuit. All ground connections must be checked periodicallyto determine that they are mechanically strong and electrically adequate for therequired current.When engaged in alternating current gouging/cutting under wet conditions or warmsurroundings where perspiration is a factor, the use of reliable automatic controlsfor reducing no load voltage is recommended to reduce shock hazard. When thegouging/cutting process requires values of open circuit voltages in alternatingcurrent machines higher than 80 volts, and direct current machines higher than100 volts, means must be provided to prevent the operator from making accidentalcontact with the high voltage by adequate insulation or other means.When gouging is to be suspended for any substantial period of time, such asduring lunch or overnight, all electrodes should be removed from the torch and thetorch carefully located so that accidental contact cannot occur. The torch must bedisconnected from the power source when not in use. Never immerse air carbonarc torches or electrodes in water.SMOKE, FUMES, AND GASES CAN BE DANGEROUS TO YOUR HEALTHVentilation HazardsKeep smoke, fumes and gases from the breathing area. Fumes fromthe gouging process are of various types and strengths, dependingon the kind of base metal being worked on. To ensure your safety,do not breathe these fumes. Ventilation must be adequate to remove smoke, fumesand gases during the operation to protect gouging operators and others in the area.89-250-0082-7Safety and Health
AIR CARBON-ARC GUIDEVapors of chlorinated solvents can form the toxic gas “Phosgene” when exposedto ultraviolet radiation from an electric arc. All solvents, degreasers and potentialsources of these vapors must be removed from the operating area.Fumes produced by cutting particularly in confined places can cause discomfortand physical harm if inhaled over an extended period of time. Provide adequateventilation in the gouging/cutting area. Use air-supplied respirators if ventilation isnot adequate to remove all fumes and gases. Never ventilate with oxygen, becauseoxygen supports and vigorously accelerates fire.NOISE CAN DAMAGE HEARINGPersonal Protective Equipment and ClothingNoise from the air carbon-arc process can damage your hearing. Wearprotective hearing devices to ensure protection when noise levelsexceed OSHA standards. Adequate hearing protection devices mustbe worn by operators and surrounding personnel to ensure personal protectionagainst noise.Permissable Noise ExposureDuration Per Day (hours)864321-1/211/4 or less* dBA decibelsSafety and HealthSound Level (dBA*) Slow Response909295971001021051152-889-250-008
AIR CARBON-ARC GUIDEARC RAYS, HOT SLAG, AND SPARKS CAN INJURE EYES AND BURN SKINThe gouging/cutting processes produce extreme localized heatand strong ultraviolet rays. Never attempt to gouge/cut withouta welding helmet with the proper lens, that complies with federalguidelines. A number 12 to 14 shade filter lens provides the bestprotection against arc radiation. When in a confined area, preventthe reflected arc rays from entering around the helmet. Make sure others areprotected from arc rays and sparks. Approved shielding curtains and appropriategoggles should be used to provide protection to others in the surrounding area andoperators of nearby equipment.Skin should also be protected from arc rays, heat and molten metal. Always wearprotective gloves and clothing which will not allow skin to become exposed. Allpockets should be closed and cuffs sewn shut. Leather aprons, sleeves, leggings,etc. should be worn for out-of-position gouging/cutting or for heavy metalremoval operations using large electrodes. High top work shoes provide adequateprotection from foot burns. For added protection use leather spats. Flammable hairpreparations should not be used when gouging/cutting. Wear ear plugs to protectears from sparks.Shielding BoothsWhere the work permits, the arc welder should be enclosed in an individual boothpainted with a finish of low reflectivity such as zinc oxide, an important factorfor absorbing ultraviolet radiations, and lamp black, or shall be enclosed withnoncombustible screens similarly painted.WELDING SPARKS CAN CAUSE FIRES AND EXPLOSIONSFire and Burn HazardsCauses of fire and explosion: combustibles reached by thearc, flame, flying sparks, hot slag or heated materials. Removecombustibles from the work area and/or provide a fire watch.Avoid oily or greasy clothing as a spark may ignite them. Have afire extinguisher nearby, and know how to use it.89-250-0082-9Safety and Health
AIR CARBON-ARC GUIDEBe alert to the danger of conduction or radiation, for example if gouging/cuttingis to be done on a metal wall, partition, ceiling or roof, precautions must be takento prevent ignition of combustibles on the other side. Do not gouge/cut containersthat have held combustibles. All hollow spaces, cavities and containers should bevented prior to gouging/cutting to permit the escape of air or gases. Purging withinert gas is recommended.Never use oxygen in an air carbon-arc torch.Table 1 - Recommended Minimum Air RequirementsRecommended Compressor RatingAirAirASMEType ofIntermittent ContinuousPressure1 ConsumptionReceiverTorchUseUsepsi (kPa) cfm (L/min.)Sizehp (kW)hp (kW)gal (lit)Light Duty240 (280)8 (227)0.5 (0.4)1.5 (1.1) 60 (227)General Duty225 (708)5 (3.7)7.5 (5.6)80 (550)80 (303)Multipurpose333 (934)7.5 (5.6)10 (7.5)Automatic460 (414)46 (1303)N/A15 (11.2)Pressure while torch is in operation.Accommodates flat electrodes.3Generally considered a foundry touch.4Requires some kind of mechanical manipulation.12Use only compressed air. Use of combustible compressed gases can causeexplosions resulting in personal injury or death.Safety and Health2-1089-250-008
AIR CARBON-ARC GUIDESAFETY AND OPERATING REFERENCES1. Code of Federal Regulations. (OSHA) Section 29 Part 1910.95, 132, 133,134, 139, 251, 252, 253, 254 AND, 1000. U.S. Government Printing Office,Washington, DC 204022. ANSl Z49.1 "Safety In Welding and Cutting"3. ANSI Z87.1 "Practice for Occupational and Educational Eye and FaceProtection."4. ANSl Z88.2 "Standard Practice for Respiratory Protection." American NationalStandards Institute, 1430 Broadway, New York, NY 10018.5. AWS C5.3 "Recommended Practices for Air Carbon-Arc Gouging and Cutting."6. AWS F4.1 "Recommended Safe Practices for Welding and Cutting Containers."The American Welding Society, 550 NW Lejeune RD., P.O.Box 351040, MiamiFL. 331357. NFPA 51B "Fire Prevention in Cutting and Welding Processes” National FireProtection Association, Battery Park. Quincy MA 022698. CSA Standard W117.2, "Safety in Welding. Cutting and Allied Processes"Canadian Standards Association, 178 Rexdale Blvd., Rexdale, Ontario, CanadaM9W 1R389-250-0082-11Safety and Health
AIR CARBON-ARC GUIDESECTION 3:PRINCIPLES OF OPERATIONGENERALLike arc welding, CAC-A uses an intense arc to create a molten pool on theworkpiece. Compressed air blows away this molten metal.The process requires a welding power source, air compressor, carbon electrode,and gouging torch. Figure 1 illustrates the component arrangement.COMPRESSED AIRPOWER SUPPLYELECTRODE LEADDCEP OR ACCONCENTRICCABLECARBON ELECTRODETORCHWORKPIECE LEADWORKPIECEFigure 1: Air Carbon-Arc SetupCut or gouge only in the direction of air flow. The electrode angle varies, dependingon the application. The operator should maintain the correct arc length so air willremove molten metal. See Figure 2.Principles of Operation3-1289-250-008
AIR CARBON-ARC GUIDETORCHELECTRODESTICKOUT 7" MAXTORCH HEADS ( )COPPER PEEL BACK3/4" to 2"AIR 80PSIALWAYS UNDER THE ELECTRODETRAVELWORKPIECE (-)Figure 2: Principles of Air Carbon-ArcPOWER SOURCESSingle-phase machines with low, open-circuit voltage may not work for air carbonarc gouging (CAC-A). However, any three-phase welding power source of sufficientcapacity may be used for air carbon-arc gouging. The open-circuit voltage shouldbe higher than the required arc voltage to allow for a voltage drop in the circuit.The arc voltage used in air carbon-arc gouging and cutting ranges from a low of35V (volts) to a high of 56V; thus, the open-circuit voltage should be at least 60V.The actual arc voltage in air carbon-arc gouging and cutting is governed by arclength and the type of gouging.Aside from special uses addressed later, CAC-A is used with DCEP (reverse polarity).The electrode should extend at most 7" (178 mm) from the gouging torch, withthe air jet between the electrode and workpiece. Use a minimum extension of2" (50.8 mm). Torch parts will damage if the stickout of the electrode is less thanthe 2" (50.8 mm).COMPRESSED AIRUse ordinary compressed air for air carbon-arc gouging. Normal pressuresrange between 80 psi (551.6 kPa) and 100 psi (690 kPa) at the torch; higherpressures may be used, but they do not remove metal more efficiently.Use 60 psi (413.7 kPa) with the light-duty manual torch. Do not use pressures thislow with general duty torches.89-250-0083-13Principles of Operation
AIR CARBON-ARC GUIDERegardless of the pressure used with manual torches, the air hose, supplying airto the cable assembly connected to the torch body, should have an inside diameter(ID) of at least 3/8" (6.4 mm).Mechanized torches with automatic arc-length control should have an air-supplyhose with a minimum ID of 1/2" (12 mm).Table 1 gives the consumption rates of compressed air for the manual andmechanized torches, plus the compressor power rating for intermittent andcontinuous use. Be sure the compressor’s receiver tank is large enough for thecompressor rating.ELECTRODESThe three types of electrodes are listed below.1. DC copper-coated electrodes are most widely used because of theircomparatively long electrode life, stable arc characteristics, and grooveuniformity. These electrodes are made from mixing carbon and graphite with abinder. Baking this mixture produces dense, homogeneous graphite electrodesof low electrical resistance, which are then coated with a controlled thicknessof copper. Available diameters: 1/8" (3.2 mm) 5/32" (4.0 mm) 3/16" (4.8 mm) 1/4" (6.4 mm) 5/16" (7.9 mm) 3/8" (9.5 mm) 1/2" (12.7 mm)Jointed electrodes work without stub loss and are furnished with a femalesocket and a matching male tang. Available diameters: 5/16" (7.9 mm) 3/8" (9.5 mm) 1/2" (12.7 mm) 5/8" (15.9 mm) 3/4" (19.1 mm) 1" (25.4 mm)Flat (rectangular) coated electrodes make rectangular grooves and removeweld reinforcements. Available diameters: 5/32" (4.0 mm) x 3/8" (9.5 mm) 3/16" (4.8 mm) x 5/8" (1-5.9 mm)Half Round coated electrodes provides versatility of having both a round andflat electrode. Available diameters: 3/8" (9.5mm) x 5/32" (4.0mm)Principles of Operation3-1489-250-008
AIR CARBON-ARC GUIDE2. DC plain electrodes are used in diameters of less than 3/8" (9,5 mm). Duringgouging, they consume more rapidly than coated electrodes. They are madelike the coated electrodes, but without the copper coating. Available diameters: 5/32" (4.0 mm) 3/16" (4.8 mm) 1/4" (6.4 mm) 5/16" (7.9 mm) 3/8" (9.5 mm)3. AC coated electrodes are made from carbon, graphite, and a specialbinder. Rare-earth materials are added to ensure arc stabilization whenusing alternating current. These electrodes are coated with copper.Available diameters: 3/16" (4.8 mm) 1/4" (6.4 mm) 3/8" (9.5 mm)Table: 2 Suggested Current Ranges (AMP) ForCommonly Used Electrode Types and SizesElectrodeDC ElectrodeAC ElectrodeAC ElectrodeDiameterDCEPACDCENin (mm)min - maxmin - maxmin - max1/8 (3.2)60 - 90N/A5/32 (4.0)90 - 1503/16 (4.8)200 - 250200 - 250150 - 1801/4 (6.4)300 - 400300 - 400200 - 2505/16 (7.9)350 - 450N/A3/8 (9.5)450 - 600350 - 450300 - 4001/2 (12.7)800 - 10005/8 (15.9)1000 - 12503/4 (19.1
Air carbon-arc gouging began in the 1940s, evolving from the existing carbon-arc cutting process. Myron Stepath, a welding engineer, developed air carbon-arc gouging to remove several hundred feet of flat, cracked, stainless steel weld. Previously, carbon-arc cutting remov
Jun 30, 2013 · Air carbon-arc gouging began in the 1940s, evolving from the existing carbon-arc cutting process. Myron Stepath, a welding engineer, developed air carbon-arc gouging to remove several hundred feet of flat, cracked, stainless steel weld. Previously, carbon-arc cutting removed overhead and vertical defective welds and rivet heads.File Size: 920KBPage Count: 44
For Reference Only ARC 8D ARC 10D ARC 12D ARC 15D Dimensions And Specs 1 Recommended Enclosures ARC 8D 2 ARC 10D 2 ARC 12D 3 ARC 15D 3 . .65 cu.ft. .75 cu.ft. .85 cu.ft. Minimum SPL SQ ARC 10D2 ARC 10D4. 3 TOP NOTE: These woo
High Current Level Arc "Parallel Arc" An Arc Fault That Occurs at 75Amps and higher An Arc Fault That Occurs Line-Line or Line-Neutral Types Of Arcing Faults Low Current Level Arc "Series Arc" An arc fault at low levels down to 5 Amps An arc fault at a break or gap in a single conductor in series with a connected load
Arc Flash Facts Arc Flash Fact Sheet Brady Arc Flash Training Aids Promote awareness of the dangers associated with arc flash accidents and make sure your workers know how to protect themselves! Poster Highlights the common causes of arc flash and provides safe work practices and personal protection equipment requirements
HMP presents a wide range of AR -200 or MMA-200 of 200 AMP single phase inverter welding machine. These ARC Welding machines are available in various model ranges. HMP have a wide range of 200A ARC inverter welding machine with all standard accessories. HMP have 200A models of Welding as ARC-200N, ARC-200G, ARC-200MOS, ARC-200L, ARC-
Apr 30, 2008 · Carbon Arc Cutting/PACCarbon Arc Cutting/PAC 16 16 Hardfacing 10 Wee d g ( ot de ed & ed)lding (not defined & mixed) 21 . GTAW Gas-Tungsten Arc Welding (TIG) GMAW Gas-Metal Arc Welding (MIG) SMAW Shielded Metal Arc Welding (Stick or Manual Arc Welding) FCAW Flux Core Arc Welding. Step 2: Filler Metal/Base Metal .
130.5 Arc Flash Risk Assessment. An arc flash risk assessment shall be performed and shall: (1) Determine if an arc flash hazard exists. If an arc flash hazard exists, the risk assessment shall determine: a) Appropriate safety-related work practices b) The arc flash boundary c) The PPE to be used within the arc flash boundary
6 Introduction to Linguistic Field Methods :, We have also attempted to address the lack of a comprehensive textbook that p.resents the rudiments of field methodology in all of the major areas of linguistic inquiry. Though a number of books and articles dealing with various aspects offield work already exist esee for example Payne 1951, Longacre 1964, Samarin 1967, Brewster 1982, and other .
