The influence of surface strengthening of hard-alloy tool on high strength cast iron manufacturability

Abstract

Problem. High-strength cast irons are characterized by considerable strength and rigidity, heterogeneity of structure, which leads to reduced machinability. Cast iron is characterized by significant heterogeneity in both structure and chemical composition, which contributes to the intensification of the fatigue wear of hard alloys. The process of introducing cast iron with a high level of performance is hampered by an insufficient level of machinability. Improved machinability is achieved not only by changing the structure and properties of cast iron, but also by cutting conditions. Goal. The goal is choozing the optimal method of reinforcement of the VK8 tool used in machining high-strength cast iron to reduce the intensity of fatigue fracture and improve the workability of cast iron. Method. The carbide tool was subjected to vibration abrasive and shot blasting. Sturdy studies were performed in the longitudinal turning of high-strength cast iron on a lathe. Worn tool surfaces were examined using an EM-100BR electron microscope and a REM-200 scanning electron microscope. Results. A typical type of wear for a carbide tool when machining highstrength cast iron with spherical graphite is adhesive-abrasive and fatigue fracture. Studies have shown that hardening of a carbide tool with surface plastic deformation by blasting is a more effective method of improving the reliability of the cutting tool and improving the machinability of high-strength cast iron than vibrating. Scientific novelty. Shot blasting helps reduce the intensity of fatigue fractures of carbide tools when machining non-uniform high-strength cast iron due to the small rounding of the cutting edges and increased strength. Practical significance. Shot blasting leads to a 1.3-fold increase in tool stability, a decrease in the scattering coefficient, and an 1.4-fold increase in destructive flow.