RU2352443C2 - Welding flux coated by aluminium - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: flux contains components in a following ratio, wt %: transition metal oxide 20-30, cryolite 21-24, sodium chloride 14-16, potassium chloride 35-40. Transition metal oxide promote aluminium oxidation while steel welding with aluminium coat. Sodium chloride and potassium chloride provides stable arc burning while steel welding by flux layer, and cryolite dissolves aluminium oxide and removes it into slag.

EFFECT: mechanical properties increasing of weld metal.

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Description

The invention relates to welding materials, namely to fluxes for welding on a flux layer of steels having a metallized aluminum coating.

Known flux for welding steels coated with aluminum (Flux for welding steels coated with aluminum, USSR author's certificate No. 1274894, V23K 35/362. Published 07.12.86. Bull. No. 45), containing the following components, wt.%:

Zircon Concentrate 7.1-11.8 Nickel 22.9-37.6 Fluorspar 26.0-35.9 Marble 24.6-31.1

This flux allows you to bind aluminum and remove oxidized aluminum from the weld when the thickness of the aluminum coating is not more than 450 microns when welding in carbon dioxide.

Known flux for welding steels coated with aluminum (Flux for welding steels coated with aluminum, patent for invention No. 2279342. Published July 10, 2006 Bull. No. 19), containing the following components, wt.%:

Zircon Concentrate 7.1-11.8 Nickel 22.9-37.6 Fluorspar 9-12.6 Cryolite 41-57.4

This flux makes it possible to more effectively remove oxidized aluminum from the weld metal due to the formation of a more fusible eutectic, which helps to increase the mechanical properties of the weld metal when welding in carbon dioxide. However, when welding over a flux layer in an inert protective atmosphere, this flux does not oxidize aluminum. Aluminum promotes the formation of intermetallic phases with iron, which reduce the mechanical properties of the weld metal.

The technical result of the invention is to increase the mechanical properties of the weld metal.

The technical result is achieved in that the flux containing cryolite additionally contains sodium chloride, potassium chloride and transition metal oxide in the following ratio of components, wt.%:

Transition Metal Oxide 20-30 Cryolite 21-24 Sodium chloride 14-16 Potassium chloride 35-40

Such a combination of new features with the known ones ensures the oxidation of aluminum during welding in an inert protective gas medium and the removal of aluminum oxide into slag, thereby increasing the mechanical properties of the weld metal.

When welding steels with aluminum coating in an inert gas environment, transition metal oxides, due to their lower affinity for oxygen, oxidize aluminum to aluminum oxide by the reaction:

2 / yMe _x O _y + 4 / 3Al = 2x / yMe + 2 / 8Al ₂ O ₃

The reduced transition metal alloys the weld metal. Reducing the content of transition metal oxide reduces the oxidizing ability of the flux. An increase in oxide content decreases the stability of arc burning.

Cryolite dissolves alumina and helps to reduce the content of alumina in the weld metal.

Sodium chloride and potassium chloride in the indicated proportions ensure stable combustion of the welding arc.

An example of the application of this flux is the technology of argon-arc welding of steels coated with aluminum over the flux layer in an inert gas environment with a non-consumable electrode. For welding, plates of 500 × 150 × 2 of St3 steel with a clad aluminum layer are used. Before welding, flux paste with the optimal content of components, wt.%: Is applied to the edges of the plates:

Chromium oxide thirty Cryolite 21 Sodium chloride fourteen Potassium chloride 35

The flux paste is prepared by mixing the components of the flux with liquid glass in a ratio of 1: 0.5 by weight of the dry mixture. The use of this flux allows to reduce the aluminum content in the weld metal by 2-2.5 times and the content of aluminum oxide by more than 1.5 times, which helps to increase the mechanical properties of the weld metal.

The proposed flux provides a technical effect and can be obtained using means known in the art. Therefore, it has industrial applicability.

Claims (1)

A flux for welding aluminum-coated steels containing cryolite, characterized in that it additionally contains sodium chloride, potassium chloride and transition metal oxide in the following ratio, wt.%:
Transition Metal Oxide 20-30 Cryolite 21-24 Sodium chloride 14-16 Potassium chloride 35-40