Comparison of coated and uncoated HSS drill bit on surface roughness, material removal rate and dimensional accuracy of SS410 stainless steel

Abstract

Stainless Steel 410 (SS410) is 12% chromium martensitic steel which can be heat treated to obtain wide range of mechanical properties. Due to its high corrosion resistance and excellent combination of toughness and strength, it is used for furnace parts, steam turbine buckets, blades, pump, nozzle, automotive parts, aerospace application etc. Considering the challenges in machining of this material, drilling experiments were conducted on SS410 to analyse the effect of various parameters. Coatings always have a positive influence on the tool. It helps to reduce friction in the cut, reducing heat build-up in the drill bit, as well as improving the flow of material out of the drilling point. It also delivers protection against corrosion, rust and water damage. The AlTiN coating provides exceptional oxidation resistance and extreme hardness. This coating works well in very demanding cutting tool applications, especially when tools are being pushed to the max. This paper reports on the investigation of performance of Al-Ti-N coated and uncoated HSS drill bits when drilling SS410. Machining characteristics studied in this investigation include Material Removal Rate (MRR), Surface Roughness (Ra), Ovality. Drilling tests were carried out as per Taguchi’s L16 array using process parameters such as Speed (30, 40, 50, 60 m/min), Feed (F) (0.05, 0.075, 0.1, 0.125 mm/rev) and point angle (P) (100, 110, 120, 130 degree). Comparison of the performance of coated and uncoated drill bits showed that coated drill bits have higher performance than uncoated. By using coated drills surface Roughness and Ovality values of drilling are reduced to an extend of 48.5% and 2%. Material removal rate value is also improved to an extend of 23%.