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August 12, 2017 18:08

Welding flux - how to protect the connection correctly ?

essence of the flux during welding

Ferrous and non-ferrous metals in general are one of the most important types of construction materials, play an important role in almost all human activities.Often there is a need for a reliable connection of metal structural elements.

Of the many ways to perform metal welding provides high strength and reliable connection.Species and technologies developed many.Welding arc and gas welding of them are very common, active and widely used in construction works, industrial production, works in the field of energy, etc.

Among the requirements to the seam is important to protect the weld zone.Oxides formed during welding have a melting point higher than that of metal, it greatly impairs the connection.The task of the flux is to protect from the oxides, which could affect the properties of the suture connection, and the formation of easily removable slag.This is achieved by the inclusion of chemical compounds.

Therefore, being a composite material rather complicated, flux for welding protects the molten metal and the impact zone (arc or torch) from oxygen and nitrogen, making combustion more stable and powerful.It contributes to the restoration of oxides and liquefied slag temperature drops and their connections, thereby creating the conditions for their floating on the melt surface for subsequent removal.

In what form can be detected flux for welding?

Modern fluxes can be manufactured as a single material or as a one-piece construction.For example, the outer layer of the coating on the material of the welding rod forms a one-piece construction of the welding electrode, which has become a standard and widely disseminated.

Like the electrode, welding wire with flux is widely used in mechanized welding with shielding gases without them.The wire is wound into a reel, and it is located in the flux of the core.It also performs the task of protection of the weld pool.

Another type of bobbin material for automatic and semi-automatic welding machine is a welding wire powder.Structurally it consists of a tube electrode with a mixture of flux and metal powder inside.It is also a fluxing welding wire.

flux and then reduces the release of harmful dust and gases, increases the depth and power of the melt, thereby providing greater uniformity and quality of the weld.Also, fluxes are present in special additives to obtain a predetermined chemical purity, increased seam strength characteristics, their doping.

Application of flux - determined with the types of work

Depending on the type of metal, the type of welding different fluxes are used.So, the first group of flux used for welding carbon steel and alloy steel.For high-alloy steels used fluxes of the second group.Accordingly, the welding is carried out with the use of a third, a large group of fluxes for non-ferrous metals and alloys.

example, specialized welding flux for aluminum in the structure may contain sodium, potassium, lithium and barium.In addition, this flux has a fluorspar.The composition for aluminum welding wires used as silicon, manganese, magnesium, zinc and iron.

course, depending on the type of flux, and the wire electrode, and changing the composition ratio of the components.But we must also note the presence of the universal flux, some of them can be used to work with metals of other groups.

As already mentioned, many tasks performing welding also solved with the use of gas welding.The factor of its use is smooth and gradual heating of the metal parts to be connected.Particularly appropriate use of gas welding in works that require such gradualism.

For example, when working with cast iron and special and tool steels.As in the case of arc welding, gas welding fluxes to protect the melt from formation of refractory oxides, promote slag formation with low melting points.Such slags form a thin protective film on the surface suture connection.

And therefore when gas welding to fluxes are requirements: low density (should float on the surface of the melt), fluidity (less metal melting temperatures), adhesion and fluidity of the melt, the ease of entry into reaction with the oxide films and metal oxides (for the formation of low-temperatureslag) and security for people and materials.

Since metals, like alloys, set flux materials only for the welding gas is known more than one hundred items.Here applied, for example, silicic and boric acid, borax, multicomponent their combinations.