Study On Cutting Mechanism And Tool Wear Of Two Kind Tools For Hard Milling3Cr13Cu

Milling of hardened steel is a topic of high interest for today’s industrialproduction and scientific research. In cutting process, the workpiece materialof poor high hardness and thermal conductivity, such as hardened steel, alloysteel, titanium and ultra-high strength steel, can achieve serrated chip in awide range of cutting conditions. Periodic serrated chip formation bringshigh-frequency variations of cutting force, leading the process quality andtool life deterioration. In this paper, two kind tools were used to face millingthe martensitic stainless steel under different parameters to study theinfluence of cutting parameters on chip morphology, cutting force,temperature and tool wear, to analysis the influence of the serrated chipformation on tool wear, and to discuss the formation mechanism of serratedchip. The cermet cutting tools were used to Z-axis milling3Cr13Cu, to revealthe crack formation rule of the rank face of the cermet tool. Experimentalstudies of the above expect to provide a theoretical basis for custom thestainless steel processing technology.(1) By analyzing the free surface, back surface and cross section of the chip,the results show that different material tools affect the chip morphology. Thebetter thermal performance of the cutting tool, the higher the critical speedform serrated chip. With the increase of cutting speed, the length between thesaw-tooth segment tips decreases, while the chip serrated radio increases.(2) Through analyzing free surface, back surface and cross sectionalmorphology of the chip and the tool wear influence on chip morphology, theresults show that serrated chip is composed of adiabatic shear mechanism inthe milling process of martensitic stainless steel (3Cr13Cu).(3) By monitoring and analysis of the cutting force variation of cuttingparameters, in the speed range140-230m/min, cutting force decreases with thecutting speed increases. The cutting parameters (cutting speed, feed rate anddepth of cut) have great contribution on cutting temperature increase. And inthe finished tests, the highest machined surface temperature does not exceed230oC. Based on the experimental results, the empirical formulas of thecutting force and cutting temperature were developed. (4) The variation of the tool wear with the cutting parameters wasinvestigated, and the crack formation rule of the cermet tool is revealed. Atlower cutting speeds, the mechanical fatigue crack is produced earlier than thethermal crack at the tool rake face, while at higher cutting speeds, it is thethermal crack was generated earlier at the tool rake face. During the millingprocess with cermet cutter, d1is defined as the axial milling distance whencrack primary appeared, and d2is defined as the axial milling distance thatZ-axis moved distance during the cracks just formed into the tool failure.With increasing speed, d1and d2were decreased.