Page 429 of 561

WIRE WELDING

Application areas

GMAW and FCAW processes cover a wide range of applications known from MMAW (coated electrodes) and partly also the TIG process. Among the most distinct advantages of the processes are: • Welding technique is easy to learn. • High quality welds.

• High deposition rate. • No slag, or for FCAW very little slag. • Unique advantages for sheet metal and aluminium welding.

The last may be the most important advantage for repair and maintenance applications, as especially aluminium welding with gas or coated electrode is difficult and requires considerable experience and skill from the welder. The only other alternative, TIG, need special equipment and is only usable on materials of limited thickness. Disadvantages of the process have been among others heavy equipment and the need for using several different premixed shielding gases for different metals and alloys. These are to a large degree being eliminated by design of equipment as described under the UWW-161 TP and UWF-102 principle, and by carefully selecting wires with or without flux core according to application area. Non-ferrous metals

4.03

428

Aluminium and copper alloys are excellently weldable both in spray- and short-arc mode using argon as shielding gas, and solid wire filler material of Alumag, lcuni and lalbro type. Overlap between short- and spray-arc mode will normally be in the material thickness range 3–6 mm, even though thicker materials may be welded with UWF-102 and short arc. Welding is easily done in all positions.

Unalloyed/Iow alloyed and stainless steels Numerous gas mixtures based on Argon, Oxygen, Carbon Dioxide, Helium, Hydrogen, and even traces of other gases, have been introduced to the market for ferrous materials, all claiming their superiority for certain alloy types, welding positions, arc types etc. In onboard repair and maintenance a stock of several gas mixtures will be expensive and highly impractical, and with proper selection of filler material, not necessary. Based on one shielding gas, a mixture of 75-80% Argon and 20-25% Carbon Dioxide, the following applications are covered: • MS type solid wire, short-arc, all positions, all steels weldable with GPO/GPR/SPECIAL /LH/LHV electrodes.

• 18/8 type flux cored wire, all positions all stainless steels weldable with 18/8 electrodes or 18/8 Mo rods.

• 23/14 type flux cored wire, all positions all stainless steels weldable with 23/14 electrodes. Flux cored wires with self-shielding properties requiring no shielding gas at all are being developed to cover an expanding range of applications, and will further add to the usefulness of the GMAW/FCAW processes in onboard repair and maintenance.