There are a range of factors to consider when weighing up choices for wire-feed welding on a particular job.
Welding in a workshop provides a range of benefits to the tradesman. One has all the equipment they require at their disposal for fabrication, as well as the benefits of comfort and shelter from the elements.
However, not all welding is done under such ideal circumstances, and in the case of construction projects, a good deal of forethought and preparation is required to ensure all the welds, especially those in cross-country pipelines and field structural fabrication, surpass testing standards.
For MIG welding, gas is one of the most important parts of the job. Typically a mix of 75 per cent argon and 25 per cent carbon dioxide, welding gas is used to shield the arc from the ravages of oxidation, which can cause problems in the form of porosity and poor penetration.
Unfortunately, transporting welding gas around a construction job can be costly. Leaving aside the purchase and delivery costs of the additional material, heavy argon gas cylinders are often loaded into large racks which require expensive crane movements for transport around sites.
In planning for a job in the field, among the diverse array of logistical concerns, there is a key product which can simplify a range of anticipated planning requirements, one which removes the need for the purchase, delivery, and onsite transport of gas bottle, and which can also reduce project overheads to enable companies to become more competitive in the tender process.
Flux cored wire designed for wire feed welding simplifies the planning process by precluding the need for argon to shield welding arcs.
“With the need for gas taken out of the equation, there are a number of advantages to using self-shielded flux cored wire, especially when working on construction projects in the field.”
It’s important to account for the elements when working outdoors. The gas shielding required with solid wire welding is easily disrupted by even slight wind, as the small amount of argon is blown away from the welding arc.
This necessitates the building of shelter, commonly known as a welding humpy in Australia, in order to make sure air around the weld is kept still. Building and shifting humpys means more trades assistants are required to make up hours on the job, to prevent higher paid coded welders from having to perform simple tasks.
In a typical MIG welding setup, gas shielding prevents spatter as well as oxygen contamination in the weld. The gas also assists with achieving maximum penetration with the weld, and higher levels of deposition.
The self shielded flux core serves not only to prevent the molten weld pool from atmospheric oxidisation, but also acts as a deoxidiser to scavenge any contaminants already present in the material. Although proper steel preparation is the key to achieving good welds, the de-oxidising elements in flux-cored wire trap contaminants, such as rust, mill-scale or oil, in the weld pool and hold them in slag coverage, which prevents the problems associated with welding “dirtier” steels. This aspect of flux-core wire can help to achieve higher productivity on the job without the need of onsite shielding gases.
To find out more download our case study: Gasless flux cored arc welding (FCAW) wires vs. MIG?