Presentation on theme: "Air Carbon Arc Cutting and Gouging"— Presentation transcript:
1 Air Carbon Arc Cutting and Gouging NCCER Welding Level one- Unit 4
2 IntroCarbon arc-cutting (CAC-A) is an arc cutting and _________ process. The base metal is melted with an ______________ formed between a carbon electrode and the base metal.A jet of __________________ passes through the electrode holder and its head blows the molten metal away.This process can be used in _____________________ on any type of metal that will conduct electricity.It is primarily used to gouge welds, gouge out defective welds, and to prepare ____________ for welding.
3 CAC-A ProcessCAC-A process uses a high current electric arc between the base metal and the end of a carbon graphite electrode to melt away the base metal.The currents used with CAC-A electrodes are ______________ than those required for same size SMAW electrodes.The size of the groove to be cut can be controlled by electrode size, amps, travel angle, electrode movement, and air pressure.
4 CAC-A Power SupplyEither AC or DC constant power sources can be used but ___________________ is preferred.Type of current used depends on the type of base metal to be cut.
5 Air supplyA CAC-A torch requires _______________________ to blow the molten metal away from the cut.Compressed air is supplied to the torch through a hose attached to a fitting on the end of the torch cable.The pressure on the torch regulator should always be set for the _____________________ that will reliably do the job.Because the molten metal tends to splatter, make sure that ________________________________ or screens are set up to protect any equipment or personnel near the work area.
6 CAC-A ElectrodesElectrodes used for cutting and gouging are composed of a blend of carbon and graphite with a binder material, which is baked to produce a uniform structure.There are three basic types:Plain, Copper coated for DC current, and Copper coated for AC current
7 ElectrodesPlain- Do not have a copper coating and run at ____________ surface tempsCopper coated for DC current- most common, carry more current, and operate at cooler temps.Copper coated for AC current- contain rare earth metals that help stabilize the arc. Used to cut _______________
8 ElectrodesElectrodes are also manufactured in several styles, each with a range of sizes…These types are:Round, Round jointed, and special shapes_____________________ electrodes are designed to make special shaped grooves or cuts. Special shapes include flat and half round. Flat electrodes are designed for close tolerance metal removal._________ electrodes are specified by the widths of their widest side.
9 SafetyRemember that CAC-A work generates ___________________ and heavy smoke and fumes.Always take the proper safety precautions to ensure that nobody is harmed during this type of welding.Make sure that proper ___________________ is available before starting.
10 CAC-A EquipmentCAC-A equipment consists of the arc torch and its attached cable. The torch cable must be attached to a welding machine and a compressed air source.The connecting cable on a CAC-A contains both an ______________________ and a compressed air hose.Always be sure to position the _________________________ where the welding currents will not pass through seals, bearings, or other parts that could be damaged from arcing.
11 Washing________________ is the process of cutting objects or projections (Such as bolts or rivet heads, old welds, and other unwanted materials) from the surface of a base metal to leave a flush surface.Typically use a _____ degree push angle to ensure a good wash.Any notches left in the base metal also have a tendency to trap slag during welding.Dross or carbon deposits left on a surface to be welded will combine with the base metal to form _____________________ and porosity in the weld zone.
12 Gouging___________________ is a process of cutting a groove into a surface, usually to prepare it for welding.When gouging, the electrode size determines the minimum groove width.Special shaped electrodes can be used to cut special shaped grooves.To create a shallow gouge, you should advance the electrode __________________.