The use of the Laser Metal Deposition method, which is the metal additive manufacturing type of Industry 4.0, is becoming widespread in the coating business of powder metals.
Repairing large metal parts with this method has also been an important line of business. Metals that require good high-temperature resistance, oxidation resistance, corrosion resistance, fatigue performance, and fracture toughness in high-temperature environments, which are considered severe conditions, are mostly superalloys. Since cobalt is difficult to process, the production of parts gains importance with the LMD method which uses powder metal and has forging quality mechanical properties. Cobalt-based superalloys are used especially in aviation, in parts that are under high temperature and load, such as the jet engine's working blade, turbine discs, hot end parts of combustion, and hot air parts. AISI 4140 steel is used in large proportions in shafts, crankshafts, bolts, nuts, various gears, milling spindles, rings, shrink disks, steel conveyors, and rollers, armatures, and rifle or other barrel constructions, which are considered easy to machine and in temperatures up to 600°C. For this study, 12 discs were prepared from AISI 4140 steel and Stellite cobalt superalloy was coated on half of the discs by the LMD method. The wear performances of these two separate discs at 50N load were built at six different temperatures from room temperature to 800°C in the Pin-on-Disc machine manufactured for the purpose. Uncoated steel was oxidized especially at temperatures of 650°C and 800°C, resulting in less weight loss at 650°C and weight gain at 800°C.
Anahtar Kelimeler: AISI4140, LMD, Stellite, Cobalt Superalloy Coating, Pin on Disc, Wear.