Effect of milling parameters on machinability of SA508-3 steel in high-speed milling with uncoated and coated carbide tools

SA508-3 steel is popularly used to produce core unit of nuclear power reactors due to its outstanding ability of anti-neutron irradiation and good fracture toughness. Additive forging is a new technology for manufacturing SA508-3 steel forgings. However, the production efficiency and interface bonding quality of heavy forgings are respectively limited by the processing efficiency and surface quality of substrates in the additive forging process. High-speed milling technology is an effective method for improving machining efficiency and quality. Unfortunately, only a few studies on the milling of SA508-3 steel have been reported. In this study, we studied high-speed milling of SA508-3 steel and compared the cutting performances of uncoated, titanium aluminum nitride (TiAlN)-coated, and Al2O3-coated carbide tools. The tool life and cutting force were evaluated using various milling parameters under dry milling conditions. The wear modes and mechanisms were also investigated. The results show that adhesive wear occurs more frequently in the uncoated carbide tool, whereas coating flaking is predominant in the Al2O3- and TiAlN-coated carbide tools. Furthermore, the Al2O3-coated carbide tool showed better cutting performance than the TiAlN-coated and uncoated carbide tools considering the tool life and surface quality. The tool life of the Al2O3-coated carbide tool reached 200 min and the removed workpiece material was 182 x 103 mm3 under the blunt tool criteria. The study of tool life and wear behavior based on the practical cutting experiments contribute to the improvement of the milling quality and provides a theoretical basis for tool material selection and process optimization in milling SA508-3 steel.