Investigation of in-situ cryogenic assisted machining of 2205 duplex stainless steel in AWJM

Abstract

An experimental investigation on Abrasive Water Jet Machining (AWJM) of duplex steel at cryogenic temperatures is discussed in this work. Material removal takes place in AWJM by abrasive induced fracture. The lowering of temperature during machining induces brittleness in metallic material. Hence, by reducing the temperature of the work piece, the occurrence of abrasive induced fracture can be promoted and the MRR will be increased. In this study, a 2205 duplex stainless steel block of thickness 20 mm and diameter 70 mm was selected as a work piece for the investigation due to its high toughness at normal temperature. Piercing experiments were conducted at three different pressures (254, 271, and 302 MPa) and three different stand-off distances (SOD) (2, 3, 4 mm). The work piece is machined at non-cryogenic temperatures between 28 °C and 35 °C. Subsequently, it is repeated at cryogenic conditions with the temperature ranges below −50 °C and their respective piercing times are noted. Comparison of machining at the normal and cryogenic temperatures, with a high pressure of 302 MPa and SOD of 4 mm, revealed 28.57% reduction in piercing time while machining under cryogenic temperature. Where-as, at low pressure of 254 MPa and SOD of 2 mm, the reduction in piercing time for machining at cryogenic temperature is about 5.84% only.