Weldability of spheroidal graphite ductile cast iron using Ni / Ni-Fe electrodes

Abstract

Weldability of spheroidal graphite ductile cast iron was established using a cheap Ni-Fe and a high purity Ni electrode. A preheating treatment at 350 °C and an annealing treatment at 850 °C were carried out to improve mechanical properties of welded pieces. The pure Ni electrode showed graphite diffusion in the bead with a uniform distribution of phases, improving weldability and decreasing fragility. Preheating and annealing treatments increased ductility and improved weldability. KeywordsWeldability; Ductile iron; Electrodes; Microstructures; Arc welding. Soldabilidad de aleaciones dúctiles de grafito esferoidal utilizando electrodos de Ni y Ni-Fe ResumenSe establece la soldabilidad de funciones dúctiles de grafito según las características mecánicas alcanzadas, utilizando un electrodo puro de Ni mientras se compara con uno más económico de Ni-Fe. Diferentes tratamientos térmicos son propuestos y analizados. El electrodo de Ni puro mostró difusión de grafito desde el material original al cordón de soldadura, dando como resultado una fase homogénea que mejoró la soldabilidad y redujo la fragilidad. Un pre tratamiento a 350 °C y un recocido a 850 °C incrementaron la ductilidad y mejoró la soldabilidad. Palabras claveSoldadura; Electrodos; Microestructuras; Soldadura por arco.

Fume particle size distribution and fume generation rate during arc welding of cast iron

“…Although a variety of different types of filler material have been used in arc welding of cast iron, it has been recommended for a long time that a filler material with Ni as the main constituent (approx. 50–100% Ni) be used 14 , 15 ) . However, since the fumes (dust containing Ni compounds) that accumulate in the working environment when filler materials that have Ni as the main constituent are used are highly toxic, strict regulations have been imposed on their handling 16 ) .…”

Análisis mecánico y microestructural en soldadura de fundición dúctil, mediante procedimiento TIG, con diferentes materiales de aporte y enfriamiento al aire

“…The Fe-Ni alloy (Fig. 3) used as filler material is of high strength, can be mechanized with cutting tools and has good corrosion resistance (Pascual et al, 2009). It is suitable for cold welding (without heat treatment or preheating of parts) of grey cast irons and malleable cast irons, and also for the joints of these with steels.…”

Microstructural and Mechanical Properties of Welding and Thermal Spraying Coatings on Ductile Cast Iron

“…It thermal expansion is seemingly like that of the cast iron, it is tougher than other filler metals and can be machined very easily [17]. Nickel based filler materials provide the highest crack resistant weld because of their ability to precipitate carbon captured in its free form as graphite present in ductile iron [18], which allows to dissolve it by a germinating as spherulites, and in order to obtain high ductility and the slightest fragility of a weldment, it is necessary to standardize the chemical composition of the whole structure by means of preventing the formation of martensite structures and fragile carbides [19]. The weldability of the cast iron is ensured by the combination of several factors that are (i) chemical composition of the cast iron and filler material, (ii) original matrix structure and (iii) the operating mode of welding: process, preheating, post heat treatment protection gas ...etc [16,18].…”