Argon mixtures containing from 5-10% CO2 by volume are used for conventional and pulsed spray transfer welding of carbon and low-alloy steels. Welds are less oxidized than those made with argon/oxygen blends and the penetration profile is broader. Bead shape is good. Weld metal mechanical properties are excellent. Welding fume levels are low with both solid and metal-cored wires.
These mixtures can also be used for short-circuiting metal transfer on thin gauge material. At lower CO2 levels, care should be taken in selection of welding parameters in the short-circuiting mode to ensure adequate heat is available for acceptable penetration.
These gas blends can also be used with specially designed low fuming, flux-cored wires.* Depending upon the wire selected, excellent all-position performance can be obtained with a minimum level of welding fume. In some applications, when either metal-cored or these special all-position flux-cored wires are used with Ar/low CO2 blends, it is possible to complete multiple pass weld procedures without chipping or deslagging between passes.**
Argon/carbon dioxide shielding gases can be readily mixed from liquid (bulk) storage tanks for reduced gas supply costs, or supplied premixed in standard high-pressure cylinders.
* Always refer to the wire manufacturer’s recommendation for shielding gas selection.
** Up to three passes.
Praxair’s StarGold C-5 gas blend is primarily used for pulsed spray transfer welding of plain carbon and low-alloy steels:
For all-position pulsed spray welding of thin and heavy carbon and low-alloy steels such as HY-80.
Praxair’s StarGold C-10 gas blend is primarily used for spray transfer with solid and metal-cored wires:
Below are comparisons between shielding gas blends over a range of operating conditions. They are intended to provide suggestions for gas blend selection based on the criteria indicated.
Note: The selection of the appropriate shielding gas can be complex due to the variety of operating variables (base metal chemistry and thickness, transfer type, wire selection and welding position). Consult your Praxair representative to help you choose the best gas for your application.
|Wire Diameter (in)||Process||Wire Feed Speed (ipm)||Current Level (amps)||Voltage (volts)*|
* Voltage level for 60 Hz power supply. Add 2-3 volts for 50 Hz models.