Issue 48

C. Bellini et alii, Frattura ed Integrità Strutturale, 48 (2019) 740-747; DOI: 10.3221/IGF-ESIS.48.67 740 Intermetallic phase kinetic formation and thermal crack development in galvanized DCI Costanzo Bellini, Francesco Carlino University of Cassino and Southern Lazio, Italy costanzo.bellini@unicas.it, http://orcid.org/0000-0003-4804-6588 francesco.carlino@unicas.it A BSTRACT . A new class of material characterized by mechanical properties close to the traditional low and medium carbon steel is the Ductile Cast Irons (DCIs). High castability and low production costs allow them to be used in many fields, ranging from automotive to piping. In this class of iron-based alloy the content of carbon is mainly localized in the graphite nodules, which are dispersed in a metallic matrix characterized by different phases: ferrite, austenite, pearlite, martensite or their mix, depending on the chemical composition and the heat treatment. Metallic matrix is subjected to the corrosion phenomenon, and, for this reason, the study and the development of traditional and innovative protection techniques are important, mainly in critical applications. Hot dip galvanizing is one of the investigated protections because the zinc is able to protect the iron-based alloys thanks to the reduction potential that is lower than the iron one. In this work, a ferritic-pearlitic DCI (GS500) is galvanized by using a pure Zn bath at 440°C in order to generate a zinc coating at different dipping time. The presence of thermal cracks is observed by means of a Scanning Electron Microscope (SEM). K EYWORDS . Hot Dip Galvanizing; Ductile Cast Iron; Damage; Stress field. Citation: Bellini, C., Carlino, F., Intermetallic phase kinetic formation and thermal crack development in galvanized DCI, Frattura ed Integrità Strutturale, 48 (2019) 740-747. Received: 02.01.2019 Accepted: 15.03.2019 Published: 01.04.2019 Copyright: © 2019 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION ot Dip Galvanizing (HDG) is today the most important processing technique used to protect metallic materials in many aggressive environments, thanks to the low production costs of protective coatings and the ability of zinc to protect the metallic substrate against the hostile surroundings [1-3]. The zinc-based coatings protect the metallic coated substrate by a double effect:  A barrier effect, that is able to separate the external environment to the alloy to be protected;  An electrochemical protection due to the low electrochemical potential of zinc. H