PILOT-INDUSTRIAL EVALUATION OF LASER CLADDING OF A MULTICOMPONENT Co–Ni–Fe–Cr–W–C COATING ON HOT-FORGING CUTTING TOOLS

Abstract

The paper presents the results of pilot-scale tests on the wear resistance of the cutting surfaces of knives for the HATEBUR HOTmatic AMP 30 S hot-stamping machine, which feature a multi-component Co–Ni–Fe–Cr–W–C coating applied by laser cladding. The test material had the designation “6P” and consisted of a powder mixture similar in composition to CoNiFe(Cr30W5C1.5), but prepared from industrial powders in accordance with the technical requirements for robotic cladding. Tests were conducted on movable and stationary blades made of 20X13 steel, used for cutting heated rolled stock prior to stamping nut blanks (made of 40X and 35 steels). For comparison, production data on blades hardened with Stellite 6 alloy were used; the typical hardness range of this alloy was taken from literature data. It is shown that the experimental material mixture contains, wt. %: 21.6 Co; 21.5 Ni; 20.5 Fe; 30.0 Cr; 5.0 W; 1.5 C, which allows the hardening principle to be maintained while reducing the cobalt content relative to Stellite materials. The cladding was performed on the FL-Clad-R4 robotic system with preheating of the work pieces to 850 °C, six passes of the laser head, and subsequent tempering. Under industrial conditions for cutting 40X steel rod with a diameter of 26 mm at 1240–1280 °C, the best experimental cutter achieved 92,100 cuts compared to 55,200 cuts for the baseline version with Stellite 6. The premature failures identified are mainly related to the geometry of the workpieces, which required manual wire surfacing, thereby determining the direction of further technological refinement.