Microstructural analysis, radiography, tool wear characterization, induced residual stress and corrosion behavior of conventional and cryogenic trepanning of DSS 2507

• Published in: Journal of mechanical science and technology 2020, 34(6), , pp.2535-2547
• Main Authors: Sastry, C. Chandrasekhara, Abeens, M., Pradeep, N., Manickam, M. A. Muthu
• Format: Article
• Language: English
• Subjects: Chip formation; Compressive properties; Control; Corrosion resistance; Corrosion resistant steels; Corrosive wear; Cryoforming; Cutting force; Deposition; Duplex stainless steels; Dynamical Systems; Engineering; Industrial and Production Engineering; Machinability; Mechanical Engineering; Microhardness; Microstructural analysis; Original Article; Radiography; Residual stress; Rocket engines; Rocket launchers; Spacecraft components; Surface properties; Tool wear; Trepanning; Vibration; Wear resistance; 기계공학
• ISSN: 1738-494X; 1976-3824
• DOI: 10.1007/s12206-020-0529-1

In the present study, an endeavour has been made in trepanning of Duplex steel (DSS 2507) under wet and cryogenic environments. DSS 2507 steel is predominantly used in the area of defence for warhead and rocket motor casing, marine applications of submarine rocket launchers, naval components and other high end applications due to their high strength provided by two phased structure. Reduction of 35.21 % and 14.80 % is observed in cryogenic trepanning correlated to conventional trepanning analogous to cutting force and cutting temperature, respectively. This has an explicit bearing on the machinability and surface characteristics of the hole formed. Attrition of immured austenite phase fraction and curtailed carbide structure aids to the increase in the residual (compressive in nature) stress by 3.25 % in cryogenic trepanning, further causing an accretion of wear resistance and hardness. An increase in work hardness and inherent machinability property is observed with a surge in microhardness by 11-26.07 %, due to the upsurge of ferrite band along the surface. Additionally, ferrite formation ensures abatement the formation of embedded chips along the surface in cryogenic trepanning. Increase in MRR is ascertained at 0.8 % in cryogenic trepanning compared to conventional trepanning. A decrease of 30.99 % and 72.30 % in flank and crater wear, respectively is ascertained in cryogenic trepanning in correlation to conventional trepanning of DSS 2507 steel is ascertained. The corrosion resistance in cryogenic trepanning increased by 59.78 % analogous to conventional trepanning of DSS 2507 steel. In cryogenic trepanning, a passivation barrier is ascertained with interatomic spacing curtailment along with a surge of ferrite phase, causing an upsurge in the compressive residual factor.