An Analysis of the Weldability of Ductile Cast Iron Using Inconel 625 for the Root Weld and Electrodes Coated in 97.6% Nickel for the Filler Welds

• Main Authors: Francisco-Javier Cárcel-Carrasco, Miguel-Angel Pérez-Puig, Manuel Pascual-Guillamón, Rafael Pascual-Martínez
• Format: Article
• Language: English
• Published: MDPI AG 2016-11-01
• Series: Metals
• Subjects: weldability; pre-heating; ductile cast iron; microstructure; root pass
• Online Access: http://www.mdpi.com/2075-4701/6/11/283

This article examines the weldability of ductile cast iron when the root weld is applied with a tungsten inert gas (TIG) welding process employing an Inconel 625 source rod, and when the filler welds are applied with electrodes coated with 97.6% Ni. The welds were performed on ductile cast iron specimen test plates sized 300 mm × 90 mm × 10 mm with edges tapered at angles of 60°. The plates were subjected to two heat treatments. This article analyzes the influence on weldability of the various types of electrodes and the effect of preheat treatments. Finally, a microstructure analysis is made of the material next to the weld in the metal-weld interface and in the weld itself. The microstructure produced is correlated with the strength of the welds. We treat an alloy with 97.6% Ni, which prevents the formation of carbides. With a heat treatment at 900 °C and 97.6% Ni, there is a dissolution of all carbides, forming nodules in ferritic matrix graphite.