Flux function
Similar to the coated electrode, the
Flux Cored Wire manufacturer has its own formula for the flux composition. The flux composition varies with the function of the welding material.
The basic functions of flux components are outlined below:
(1) Deoxidizer and nitrogen remover
Since nitrogen and oxygen can cause pores or embrittlement of the weld metal, deoxidizers such as manganese and silicon must be added to the flux. As for the self-shielded flux-cored wire, AL should be added to the flux as a denitrification agent. The purpose of adding oxygen scavenger and nitrogen scavenger above is to purify the molten metal.
⑵ Welding slag forming agent
Calcium, potassium, sodium or silicon are all welding slag forming agents. Adding to the flux can effectively protect the molten pool from atmospheric pollution. The welding slag can make the welding props have a better appearance and can support full-position welding after rapid cooling. molten pool. The coverage of the slag can further moderate the cooling rate of the filler metal, which is especially important for the welding of low alloy steels.
(3) Arc stabilizer
Sodium and potassium keep the arc soft and smooth and reduce spatter.
⑷Alloying elements
The addition of alloying elements such as molybdenum, chromium, carbon, manganese, nickel and vanadium can increase (improve) the strength, ductility, hardness and toughness of the molten metal.
⑸ Gas former
Fluorspar, limestone, etc. need to be added to the self-shielded flux-cored wire to burn to generate shielding gas.
⒊2 Types of welding slag
The composition of the flux determines the welding workability of the welding material and the mechanical properties of the filler metal. If the composition of the flux is mainly acidic, acid slag will be generated after welding. Similarly, the alkaline (lime) flux will produce alkaline welding. scum. The welding material of the acid system is very good in weldability. During the welding process, the arc is smooth and stable, the shape is similar to the jet arc, and the amount of spatter is small.
Welding consumables whose flux is an alkaline system can obtain very good ductility and toughness of the molten metal, but the workability is far worse than that of an acidic system. The transition of molten droplets is mainly based on the transition of spherical droplets, and there are more splashes.
The development of the flux system for low-alloy steel welding consumables combines the workability of the acidic system and the excellent mechanical properties of the alkaline system.
