Consumables.ppt

19 Sep 02 * M.S.Rogers M.S.Rogers T E C H N O L O G Y Section Ref 14 Copyright ? 2003 TWI Ltd WI 3.1 * M.S.Rogers M.S.Rogers T E C H N O L O G Y Section Ref 14 Copyright ? 2003 TWI Ltd WI 3.1 Welding Inspection Consumables Course Reference WIS 5 Shielded arc filler wires, lengths or rolls Covered electrodes Shielding gases Separately supplied flux Fusible inserts Welding consumables may be: Size Classification / Supplier Condition Handling and storage Treatments e.g. baking / drying Each consumable is critical in respect to: Handling and storage is critical for consumable control Consist of a core wire typically between 350-450mm in length and from 2.5-6mm in diameter The wire is covered with an extruded flux coating The core wire is generally of a low quality rimming steel The weld quality is refined by the addition of refining agents in the flux coating The flux coating contains many elements and compounds that all have a variety of functions during welding Welding consumables for MMA To aid arc ignition To improve arc stabilization. To produce a shielding gas to protect the arc column To refine and clean the solidifying weld-metal To add alloying elements To control hydrogen contents in the weld To form a cone at the end of the electrode, which directs the arc Functions of flux constituents: MMA (SMAW) BS 639: Steel electrodes BS EN 499: Steel electrodes AWS A5.1 Non-alloyed steel electrodes AWS A5.5 Alloyed steel electrodes AWS A5.4 Chromium electrodes MIG/MAG (GMAW) TIG (GTAW) BS 2901: Filler wires BS EN 440: Filler wires AWS A5.9: Filler wires BS EN 439: Shielding gases SAW BS 4165: Wire and fluxes BS EN 756: Wire electrodes BS EN 760: Fluxes AWS A5.17: Wires and fluxes Rutile Cellulose Basic Acidic Common flux types Rutile electrodes Used mainly on general purpose work Low pressure pipework, support brackets. Flux constituents include: Titanium dioxide, slag former Clay - binding agent Sodium silicate - main ionizer Easy to use Low cost / contro