Estudio comparativo de la soldabilidad del hierro fundido nodular, soldado con material de aporte para acero inoxidable AWS E 312-16 y para hierro nodular AWS E NiFe-Cl, mediante el proceso SMAW

Abstract

The objective of this project is to carry out a comparative study of weldability of welded nodular cast iron with two types of electrodes, AWS E 312-16 and AWS E NiFe-Cl which are used to weld stainless steel and cast iron respectively, with the purpose of finding an electrode more economical in comparison with the typical electrodes manufactured with nickel core and used for this process, whose cost is high due to the problems of weldability that presents the cast iron. For the present study the AWS D11.2 standard is used, which helps to determine the preheating temperature at which the weld does not show cracking, to later weld the plates applying the preheating conditions already found, finally, non-destructive tests are carried out and destructive in order to analyze and compare the mechanical and metallurgical properties of welded joints. Based on the results of the non-destructive tests it is determined that the specimen welded with electrode AWS E 312-16 presents a transverse crack in the root of the weld bead, while the joint joined with electrode AWS E NiFe-Cl is not defective any. Metallographic analysis reveals the presence of unwanted phases in the joint welded with filler material for stainless steel, such as the sigma phase present in the area of the solder and white cast partially in the HAZ, on the other hand, the results obtained of the tensile strength are acceptable for welding with the two types of electrode, however, due to the presence of linear defects in the AWS E 312-16 welded union and according to the normative applied it is necessary that this electrode is not a good alternative for welding nodular cast iron.