Experimental Study on Effect of Machining Parameters and Environment on Drilling Characteristics of Stainless Steel 304

Abstract

Stainless Steel 304 (SS304) is a non magnetic material and has excellent corrosion resistance and forming characteristics which is mainly used in chemical, petrochemical, aerospace industries, etc. Few examples are kitchen wares, cryogenic vessels, surgical equipments and heat exchangers. However, most of these components require different machining processes to produce the desired product or assembly. But, during machining of SS 304, industries are facing major difficulties such as high tool wear and poor surface finish due to low thermal conductivity and high built up edge (BUE) tendency. Many researchers started working towards machinability of SS304 in different machining processes. Among these, few works have been started on drilling of this material. Drilling process is mainly used for assembly of structural parts and also used as primary process for boring, reaming, etc. By considering the above applications and challenges in machining of this material, the present study analyzes the effect of cutting speed, feed and machining environment on surface roughness and machining time during drilling process.Drilling experiments have been conducted in a jig boring machine using 10 mm diameter HSS twist drill bit by varying cutting speed (16, 22 and 28 m/min), feed (0.08, 0.12 and 0.16 mm/rev) and machining environment (dry, normal soluble oil flood coolant and kerosene) as per Taguchi’s L9 orthogonal array. The results indicated that, average surface roughness (Ra) increased from 2.088 μm to 6.647 μm when increase in cutting speed and feed. Roughness value decreased for kerosene environment compare to dry and coolant environment. Also, machining time decreased from 15.01 second to 5.58 second when increase in cutting speed and feed along with kerosene environment compared to dry and flood coolant condition.