Flux cored electrode

Abstract

A flux cored electrode including a metal sheath surrounding a core of particles containing a flux system with dispersed magnesium particles in generally spherical shape and having a graded size to pass through a number 30 U.S. Standard sieve.

Description

[0001] The present invention relates to a flux cored electrode used in electric arc welding and more particularly to the use of a specific form of magnesium particles in the core of the electrode or wire. BACKGROUND OF INVENTION [0002] Flux cored electrodes have been used for many years and include an outer metal sheath sized around an inner core of particles forming a flux system. To control the composition of the weld metal formed by using the electrode in an electric arc welding process, the core generally includes a number of metal particles to be melted and alloyed into the weld metal resulting from the welding process. It is common practice to use magnesium particles in the core of the electrode so these particles are evenly dispersed with the other core particles to produce a flux cored electrode. The use of small magnesium particles in flux cored electrodes is common. [0003] The flux in a cored electrode that produces high impact welds while welding vertically up or overhead...

AI Technical Summary

Benefits of technology

The present invention relates to a flux cored electrode used in electric arc welding that uses magnesium particles in the core of the electrode. The technical effect of this invention is to reduce the amount of magnesium in the flux cored electrode and the amount of magnesium oxide formed during the welding process, which improves the toughness and blow hole resistance of the weld. The invention achieves this by using a specific form of magnesium particles in the electrode or wire, which prevents hydration and oxidation of the magnesium particles and reduces the amount of magnesium oxide formed during the manufacturing process.

Problems solved by technology

Furthermore, thin coating of the small magnesium particles was a delicate and expensive process.

Consequently, the thin coating of the otherwise high mass reactive magnesium particles with the extreme high surface reactivity, engendered by the large surface ratio, was only theoretical and not practical.

Thus, a suggestion to reduce the surface reactivity of magnesium particles for use in flux cored electrodes was not commercially viable or physically effective.

The spherical particles having small size minimizes the surface area ratio to thereby reduce the effective exposure reactivity of the magnesium particles.

The relative size of the surface area reduces the surface reactivity of the individual particles.

This coating procedure further reduces the surface reactivity of the otherwise smooth surface formed by the gas atomizing process.

Images