Microstructure and wear characterization of 1.2714 tool steel coated with non-ferrous hard fillers

In this thesis study, it is aimed to improve the performance and life time of the hot forging die used in the industry by using hard filler welding method. Damage to the die during hot forging was investigated and a plan was drawn up for improvement. The material of the hot forging die is 1.2714 hot work tool steel. Three different hard filler electrodes, nickel based and cobalt based, were used for improvement. Nickel based, Anti Crack 7015 and Thermo Weld electrodes are used, and Cobalt 1 based electrode is used as cobalt base. Gas metal arc welding method was selected as the welding method and the welding process was carried out at a constant flow rate in the protective atmosphere formed by the Ar-CO2-O2 gas mixture. Four samples were prepared for the tests and analyzes to be made after welding. One of these samples is the base material, and the others are welded samples. As a method of comparing sample properties; Hardness measurement, microstructure examination and abrasion were used. For the hardness measurement, the Vickers method was used. Average hardness values were calculated by taking multiple measurements from one sample. Microstructure examination was carried out in two steps. Prior to examining, the appropriate solutions were prepared and the etching process was carried out. In the first step, internal structures were investigated in relatively small magnifications in an optical microscope. Porosity was detected in these examinations. SEM studies were then carried out to obtain further information. In addition, XRD analyzes were performed to determine the carbides and phases in the interior. "Ball on disc" was used as the wear test method. The samples were worn for 500 m under 10 N load. Al2O3 with a diameter of 6 mm was used as abrasive balls. In general, abrasive wear was observed in the samples, as well as adhesion in some wear zones. Interpretations were made based on the hardness values, microstructure properties and wear values obtained after the comparison methods applied. It has been tried to determine which electrode is the most suitable hard filler electrode for improvement.