Flux-cored Arc Welding (FCAW)

The flux-cored arc welding process (FCAW) shown in the image below is similar to Gas Metal-arc Welding, except that the electrode is tubular in shape and filled with flux. Cored electrodes produce a more stable arc, improve weld contour, and improve the mechanical properties of the weld metal. The flux in these electrodes is much more flexible than the brittle coating used on Shielded Metal-arc Welding electrodes, so the tubular electrode can be provided in long coiled lengths.

Schematic illustration of the flux-cored arc-welding process.

The electrodes used in this welding process are usually 0.5 mm to 4 mm in diameter and the power required is about 20 kW. Self-shielded cored electrodes also are available. They do not require any external shielding gas because they contain emissive fluxes that shield the weld area against the surrounding atmosphere. Small-diameter electrodes have made the welding of thinner materials not only possible but often preferable for use. Also, small diameter electrodes make welding joints in different positions relatively easy, and the flux chemistry permits the welding of many metals.

The Flux-cored arc Welding process combines the versatility of Shielded Metal arc welding with the continuous and automatic electrode feeding feature of gas metal arc welding. The process is economical and versatile, so it is used for welding various joints, mainly on steel, stainless steel, and nickel alloys. The higher weld metal deposition rate of the flux-cored arc welding process has led to its use in joining sections of all thicknesses. The use of tubular electrodes with minimal diameters has extended this process to work with pieces of smaller section sizes.

A primary advantage of flux-cored arc welding is the ease with which specific weld metals can be developed. By adding alloying elements to the flux core, virtually any alloy composition can be produced. The process is easy to automate and readily adaptable to flexible manufacturing systems and robotics.