Oerlikon solutions for aluminium and alloys welding and cutting applications
Due to its specific features (lightness: density 3 times lower than that of steel, excellent ability to resist corrosion, correct mechanical properties …), aluminium and its alloys (Si and/or Mg) are non-ferrous metals that are more and more widely used in various industrial activities (transportation: automobile, aircraft, trucks, railway cars and naval construction – boiler making for food and beverage containers – building … ).
For TIG, power sources that can produce alternating welding current AC (CITOTIG AC/DC in the Oerlikon range of power sources for manual applications) are available. Pure argon (Ar) is the required shielding gas. With the NERTAMATIC 450 power source used for automatic applications it is possible to weld in TIG with variable polarity (single run butt welding up to 6 mm thick) or in TIG DC with helium (up to 8 mm thick).
In MIG welding various kinds of power source can be used, those providing pulsed current will be preferred due to the quality of results (CITOPULS III range for example). However Air Liquide Welding has developed a specific arc transfer mode for aluminium welding. This welding mode named Spray ModalTM can be used in different welding positions providing welding beads with excellent compacity (reduction and even suppression of porosities) and perfect penetration of the welds. Spray ModalTM is available on the CITOWAVE III machines. When aluminium MIG welding is performed, a specific care to the wire feeding has to be taken. For better results, specific contact tips, torch liners and drive rolls should be used. Push-Pull torches or guns (PROMIG PP range) are to be used for welding small diameter wires and for long distance application.
Spray Modal™ transfer is an Air Liquide Welding exclusivity for aluminium welding.
Spray Modal™ is a process that greatly reduces micro porosity and increases penetration. It can be used in all positions and is particularly effective on aluminium sheets greater than 3 mm. Spray Modal™ uses a low-frequency modulated current which has the effect of removing most hydrogen bubbles from the weld pool before solidification.
Filler material for aluminium welding should be perfectly clean, with an excellent surface aspect and without humidity. The choice of the filler metal will be done in accordance with base material to be weld. The Oerlikon range covers most the current applications. ALUROD is the name for TIG rods and ALUFIL is the wire in spool for MIG process. Specific indications for the percentage of aluminium and of alloys components (Si, Mg and Mn) follow the commercial designation.