processi di saldatura

Welding processes in Covis Group

Welding allows to chemically and physically couple two joints by melting them together or with a filler metal. This filler material can be the same as the material of the components that are joined, or it can be different (thus the name filler material).

Covis Group is specialized in two types of electric arc welding:

1 Joint welding between two metal components:
It creates a permanent connection that differs from others, e.g. nailing or gluing, that do not realise material continuity. With some autogenous welding processes, when performed correctly and according to certain principles, it is also guaranteed an almost total continuity in the material properties of the joined parts.

2 Cladding
This method offers the assurance of a strong metallurgical bonding protective layer that will not be affected or broken during the machining. We provide this service for various critical equipment for the oil & gas, steel and mining industries. As well as helping to extend the life of these components, the cladding process can also be used to revamp and refurbish existing ones. For this specific welding operation, we use various mechanized systems that apply corrosion or wear-resistant alloys.

In this article, we will look at the welding processes Covis Group offers daily to its customers.

1 Gas Tungsten Arc Welding (GTAW)
The infusible electric arc welding process shielded by inert gas is an autogenous fusion welding process in which the heat source is an electric arc that strikes between the tungsten electrode and the workpiece. In cases of manual application of this process, the filler material consists of a rod, which the welder gently introduces at regular intervals into the electric arc, gradually melting it. The electrode, molten bath, arc and filler rod are protected by a flow of inert gas fed into the welding torch. At Covis Group, this welding technique is done both manually and mechanically. In the field of surface welding, we use the GTAW hot wire process, in which the filler material is preheated by an electric current generated by an additional generator, thus enabling higher performance in terms of hourly deposition.

2 Gas Metal Arc Welding (GMAW / MIG-MAG)
Welding process in which an electric arc strikes between the workpiece and the melting wire, in which a wire continuously feeds the weld pool. Protection of the bath can be achieved by the flow of an inert or active shielding gas. In this case, we utilize solid wires. Also, the degree of process automation can be different, depending on the application, from semi-automatic to mechanised.

3 Flux Cored Arc Welding (FCAW)
This welding process is very similar both in principles and equipment to the GMAW method, however in this case it is used a flux-cored wire: this is a hollow wire that contains special powders or other solid wires that participate in the melting process. The weld pool protection can be provided solely by the fumes and slag produced by the wire itself, or by the addition of protective gas as in previous processes.

4 SMAW (Shielded Metal Arc Welding)
This is the most classic and versatile welding method that can be applied in many situations. SMAW involves an electrode and the filler material (from which the electric arc is fired). In this case, there is no shielding gas, since the electrode has a special coating that generates a protective smoke and slag during fusion, which inhibit oxidation of the weld pool and bead. This is a purely manual process.

5 SAW (Submerged Arc Welding)
This is the process in which the electric arc strikes between the workpiece and the wire. The protection of the weld pool is achieved through a flow that prevents visibility. A wire feed device continuously feeds the pool. The flux reacts chemically with the pool, generating slag. Welding in complex positions is not possible. At Covis Group, this process is used exclusively with mechanized automation.

Covis Group is a leading provider of machining, welding and engineering services with more than 25 years of experience in the field.
With a team of qualified welding engineers, welders, fabricators and CAD engineers, Covis has earned an unparalleled reputation when it comes to providing innovative solutions.

Our teams will work alongside customers, offering advice on materials, welding technologies and processes, heat treatment and manufacturing solutions, guaranteeing on-time delivery of complete turnkey projects.

Would you like to learn more about our welding processes or ask for a quotation? Contact us!


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