Conventional processes of gas shielded metal arc welding (GMAW) do not offer directly the possibility for cladding heat sensitive materials such as aluminum with iron-based materials due to intermetallic Al/Fe phases form. This paper deals with the first evaluated cladding results of aluminum components with iron-based nanocrystalline solidifying materials by controlled shielded metal arc welding processes to improve wear resistance. In the present work, the design of experiments and data evaluations are systematically applied to get the first results about the dependence between controlled arc welding process parameters and the iron-based coatings of aluminum substrate. In particular, the effect of the chosen parameters such as wire feed speed, welding speed, frequency and further factors on the heat input, welding penetration, micro hardness, rate of welding penetration and width of intermetallic phases in the interface zone are investigated. Optical and scanning electron spectroscopy provide input for further statistical evaluation. The experiments were carried out using various controlled arc technologies which offer different control over the heat input to the substrates. Different power supplies were used.

Cavitation is one of the most serious problems that affect hydraulic systems and components, mainly power turbines. Welding deposits have been traditionally used to protect components from cavitation damage. Since the protection process is normally associated to maintenance repairs (welding overlay), there are some difficulties related to weld distortion and residual stresses as well as some economic problems regarding to process efficiency and time. Thermal spraying has been recently tested as an alternative to welding in such applications. Some of the materials tested have been proved to be ineffective or inappropriate due to several causes like poor adhesion or mechanical damage. This work refers to a study of wear resistant coatings applied by thermal spraying and welding for cavitation resistance applications. The coatings were applied by High Velocity Oxygen Fuel (HVOF) and Flame Spraying and by Shielded Metal Arc Welding (SMAW). Hardness, roughness as well as cavitation resistance characteristics of the coatings were evaluated. The results show that the obtained coatings are promising for protection in cavitation resistance applications.