The innovative use of low heat input in welding: Experiences on 'cladding' and brazing using the CMT process

As is well known in the field of welding technology, the heat input in a joining process is a defining factor of the results that can be obtained in numerous aspects directly affecting metallurgical phenomena, technological properties and the integrity of the welded joint, as well as deformations and residual stresses. Furthermore, a different heat input can be decisive on process productivity and economy. This articleconcerns tests conducted in the IIS Special Welding Process laboratory with the collaboration of Arroweld Italia pertaining to two technological subjects of considerable interest, such as 'cladding' with high corrosion resistance alloys and thin layer brazing, both using continuous wire welding methods with gas shielding, in an entirely particular version known as 'Cold Metal Transfer - CMT®'. In the case of 'cladding', the most critical aspects of anticorrosion overlay, such as penetration into the substrate and level of dilution, which frequently compromise the intrinsic corrosion resistance of the coating, are investigated. On the other hand, with regard to brazing, the degree of deformability of brazed structures is investigated, as well as the impact of the process on the mechanical properties of the base material and any influence, or otherwise, of the presence of galvanizing layers on brazed joint quality (bonding, spraying, etc.).