Investigation of microstructure and wear properties of 1.2714 tool steel of Fe-based hard coatings

Hardfacing is a method used in many manufacturing industries. There are applications from food to farming, ranging from mining to chemistry. Material properties can be improved at low cost by hard filler method. This method is particularly used in hot forging dies, which are a branch of the forging industry, to improve the properties of the deformed regions or the regions that may be deformed prior to processing. With this coating, the service life of die steels can be extended. Casting or welding with a hard coating alloy on an economically suitable base material such as carbon steels significantly improves wear resistance in particular. In this study, 4 different electrodes were welded to the DIN 1.2714 die steel using gas metal arc welding method. Hardfacing by arc welding shielded gas source of AR-CO2-O2 gas mixture with the protective atmosphere that is created at a constant flow rate was carried out. After welding, samples were obtained for 4 different coatings. The hardness, microstructure, XRD and wear resistance of the coatings were investigated. Microstructure studies were performed using both optical microscopy (OM) and scanning electron microscopy (SEM). Wear tests were also performed on a ball-on-disc tribometer. Phase analyzes and some mechanical properties were analyzed using the JMatPro program.When microstructure and XRD analyzes were examined, the presence of carbides in the coatings was determined. As a result of the hardness tests carried out, it was determined that the hardnesses of all coatings were higher than the hot work tool steel of 1.2714 except the coating No. 1. It has been determined that the hardness values are related to the alloying elements present in the coatings, and the hardnesses of the carbides formed by the coatings of the carbide forming elements are increased according to the hardness values of the carbides. When the results obtained after the wear test are examined, the wear rate of the No. 2 coating with the highest hardness is lowest. The combination of 1.2714 steel plated with coatings and a solid bond between the coatings formed. When the microstructure photographs of the coatings made outside were examined, porosity formation in the transition zone was observed. The abrasion mechanism in hard coatings is determined as abrasive wear. When the EDS analyzes on post-abrasion samples were examined, it was determined that the coatings were also exposed to the adhesion wear mechanism.