Flux-cored arc welding (FCAW) is a development of the method of arc welding in a protected atmosphere (GMAW).

This welding method enhances the metallurgical performance of the welding process and the mechanics of the fill layer through the alloying elements contained in the solder. Welded wire splicing may be outter shielded or no inner shielded.

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DESCRIPTION: The fire arc between the power supply and the wiring harness coincides with the wiring, welding and welding wires. Melted metal droplets will be surrounded by molten slag. As the droplets of metal move to the puddles, the slag will float to form a loose slag that protects the weld.

The role of the drug core:

– Form a thin slag layer that protects metal droplets and welds, or generates protective gases.

– Providing oxytic suppressants, preventing harmful reactions.

– Provide the necessary elements for the metallurgical process and improve the welding metal mechanics.

– Welding arc stability.

Gas protection

Welded wire splicing may not require the use of protective gas and this feature helps to weld core coils are favored and bring more economic effect. However, when specially welded on HSLA steel and welded on alloy steel, the use of outter shielded welds has the advantage of metallurgical welds and better weld protection, Lower wall. In this case, the components of the solder containing only the components improve the mechanical properties of the weld. The process of protecting and stabilizing the arc caused by the external gas.

Protective gases are commonly used when welding core wire:

CO2: Suitable for welding carbon steel and low alloy steel. When the carbon content in welding parts is less than 0.05%, the welding process increases the carbon content in the weld by up to 0.10%. When the carbon content in the base metal is high, the process of welding results in carbon leakage that affects hardness, permeability and can cause cracks.

ATAL 2: Is the name of gas mixture 82% Ar + 18% CO2. With this type of gas we can weld with the droplet type, suitable for welding in the reverse position. In addition, the welding properties are enhanced due to the loss of manganese and silicon due to reduction of oxide reduction.

CARGAL: Is the name of gas mixture 98.5% Ar + 1.5% O2. This type of gas is suitable for welding with spray transfer. INOX HELOXAL: the name of gas mixture 85% He + 15% O2. The type of gas suitable for welding on stainless steel with spray transfer. It has the advantage of eliminating the formation of Carbide Chrome, which damages the corrosion of the diamond at the edge of the weld.

FCA welding equipment

Compared with the bare wire, the wires are slightly different. FCA welding power (welding machine) needs higher capacity because the welded wire core has higher welding currents.

The welding machine should have a welding current of 400-500 A with a loading cycle of 100%. V-A characteristic with constant voltage (CV – Constant Voltage). This feature together with the constant-speed wire-speed device will keep the arc more stable. The downside is the large short circuit. To overcome this, modern equipment incorporates electronic circuit boards to control short circuit currents. Remember that the more V-A characteristics of the soldering machine, the better the wiring of the core wire, the smaller the shifting bridge, the higher the self-adjusting sensitivity.

Welding guns are high current rated and often cooled with water. The spray nozzle and contact tube are specifically designed for greater papillae and better electrical contact.

The wiring harness in the welded wire core maintains arc length and welding currents very important. Motor wiring equipment is a constant speed type with high speed precision, fine tuning. Welded wire is usually large in diameter, not subject to high pressures, so the full wire rope should ensure good slip resistance, which is usually cross-grooved. Teflon wire glands instead of steel coils to avoid wire scratches.

In short, welding equipment welding core wire is also a GMA welding equipment, but higher requirements, better quality adjustment.

Welded wire structure

Welding wire is a hollow tube containing powdered powder inside. The core profile of the core welding wire consists of many different configurations depending on cost and usage. Wire rope composite wires can have different metal parts or powder metal containments to disperse alloy elements, create matrix structures to enhance the machine.
Core cores usually made with wire sizes 1,2 – 1,6 – 2,0 – 2,4 – 3,2 1,4 are also less popular. Rolls into 15 – 25 Kg, without copper or nickel protection.

Choose wires and gas protection

The core wire has both the GMAW feature and the features of the solder rod. When choosing the wires depending on the position, type of joints, alloy composition of welding parts that choose appropriate wire group.

Due to the solder weld method at welding current density and relatively high yield, most are applied in flat and horizontal positions. When welded in the opposite position (stand, head) choose

( Source: indian welding machine )