Tool life analysis on hybrid microwaved Aluminium Oxide inserts in dry machining of high strength steel [EMBARGOED]

Abstract

It is critical to comprehend and know the properties of the cutting tool inserts and their synthesis to achieve optimal quality in the machining sector. Aluminum oxide (Al2O3) is a high-performance ceramic material with outstanding physical properties. Al2O3 is regarded as an extremely hard material with excellent wear resistance. However, tool wear remains a serious issue in dry machining. As a result, in this study, Hybrid Microwave energy is employed to improve mechanical qualities and extend tool life. Three different types of Al2O3 inserts were employed. Al2O3 (HMW) was post-sintered with silicon carbide as the susceptor, whereas Al2O3 (MW) was post-sintered with no susceptor. These two inserts were compared to the original untreated Al2O3 sample (UT). The post-sintering processes lasted 20 minutes at 220º°C. Mechanical testing, such as density test and hardness test were carried out. The microstructure was examined using a Scanning Electron Microscope (SEM). Dry machining was used to test the tool life and wear resistance of these Al2O3 inserts at three different cutting speeds (198, 251, and 314 m/min) at a feed rate of 0.2 mm/rev and a depth of cut of 0.2 mm. Lastly, an overall cost analysis was done to compare the three different inserts used. This study employed a workpiece made of high-strength steel (KRUPP 6582). When compared to Al2O3 (MW) and Al2O3 (UT) inserts, the results showed that the density and hardness of Al2O3 inserts were increased using the HMW post-sintering procedure. The hardness of Al2O3 (HMW) is 1131.80 HV1, followed by Al2O3 (MW), 890.14 HV1, and Al2O3 (UT), 824.15 HV1. According to the data, Al2O3 (HMW) has the maximum density (4.02 g/cm3 ), followed by Al2O3 (MW) (3.96 g/cm3 ), and Al2O3 (UT) has a density of (3.88 g/cm3 ). The SEM analysis reveals that the microstructure of the Al2O3 (MW) and Al2O3 (HMW) inserts remained unaffected even after being subjected to 20 minutes of exposure to microwave energy when compared to the Al2O3 (UT) insert. The SEM analysis revealed a uniform, homogeneous, and dense structure with no observable indications of porosity or voids for the three Al2O3 inserts. Al2O3 (HMW) tool life has been enhanced by 44.2%, while the tool life of Al2O3 (MW) has increased by 18.9% when compared to Al2O3 (UT). In dry machining of high-strength steel (KRUPP 6582), HMW has demonstrated good performance in enhancing the mechanical properties and tool life of Al2O3. The cost analysis revealed that the overall cost per unit of a product during the operational cycle is the lowest when using Al2O3 (HMW), it achieved an average cost savings of 27.9% per product compared to the Al2O3 (UT) insert. Hybrid microwave heat treatment for 20 minutes at 220ºC is beneficial in enhancing the mechanical properties, increasing the tool life and increasing cost savings in Al2O3.