Schmid, OE2012-11-272012-11-271992Schmid, OE. 1992. The influence of nickel-nitrogen ratio on the deformation behaviour of austenitic stainless steels. University of Cape Townhttp://hdl.handle.net/10204/6379A thesis submitted to the Faculty of Engineering, University of Cape Town in fulfilment of the degree of Master of Applied ScienceThis study examines the effect that a partial substitution of nickel with nitrogen has on the deformation behaviour of a metastable austenitic stainless steel, AISI 301. The effect on the tensile deformation behaviour is studied in detail at various temperatures, and the effect on the impact behaviour at room temperature is given brief attention. The uniform straining ability of a metastable austenitic stainless steel, such as AISI, which is used for stretch forming applications, is promoted by transformation-induced plasticity (TRIP), which depends on the manner in which deformation-induced martensite forms during straining. This includes both the rate of martensite formation, and the stage at which the martensite is formed. In particular, incipient necking is resisted when martensite forms gradually and selectively, preventing the formation and propagation of micronecks and microcracks. The microstructures of ten alloys, each having a type 301 base composition, but systematically varying nickel-nitrogen ratios, were characterised before and after tensile deformation, using optical and electron microscopy as well as X-ray diffraction techniques. Tensile tests were performed on solution treated specimens at temperatures of 0, 20, 60 and 120 degrees Celsius. The martensite volume fraction present after a true tensile strain of 0.3 was measured, and the work-hardening behaviour of the alloys was characterised up to the point of maximum uniform elongation. All the alloys considered showed fully austenitic microstructures at the solution treatment temperature 1050 degrees Celsius, and the indications are that the nitrogen is fully dissolved. The austenite stability of the alloys however varies at room temperature. Alloys containing approximately 5 wt% nickel, with a maximum nitrogen content of 0.28 wt%, contain up to 97% retained austenite, whereas alloys with 3.4 wt% nickel and the same maximum nitrogen content, contain only up to 63% retained austenite.enNickel NitrogenAustenitic stainless steelISI 301ReportSchmid, O. (1992). <i>The influence of nickel-nitrogen ratio on the deformation behaviour of austenitic stainless steels</i> (Workflow;9369). Retrieved from http://hdl.handle.net/10204/6379Schmid, OE <i>The influence of nickel-nitrogen ratio on the deformation behaviour of austenitic stainless steels.</i> Workflow;9369. 1992. http://hdl.handle.net/10204/6379Schmid O. The influence of nickel-nitrogen ratio on the deformation behaviour of austenitic stainless steels. 1992 [cited yyyy month dd]. Available from: http://hdl.handle.net/10204/6379TY - Report AU - Schmid, OE AB - This study examines the effect that a partial substitution of nickel with nitrogen has on the deformation behaviour of a metastable austenitic stainless steel, AISI 301. The effect on the tensile deformation behaviour is studied in detail at various temperatures, and the effect on the impact behaviour at room temperature is given brief attention. The uniform straining ability of a metastable austenitic stainless steel, such as AISI, which is used for stretch forming applications, is promoted by transformation-induced plasticity (TRIP), which depends on the manner in which deformation-induced martensite forms during straining. This includes both the rate of martensite formation, and the stage at which the martensite is formed. In particular, incipient necking is resisted when martensite forms gradually and selectively, preventing the formation and propagation of micronecks and microcracks. The microstructures of ten alloys, each having a type 301 base composition, but systematically varying nickel-nitrogen ratios, were characterised before and after tensile deformation, using optical and electron microscopy as well as X-ray diffraction techniques. Tensile tests were performed on solution treated specimens at temperatures of 0, 20, 60 and 120 degrees Celsius. The martensite volume fraction present after a true tensile strain of 0.3 was measured, and the work-hardening behaviour of the alloys was characterised up to the point of maximum uniform elongation. All the alloys considered showed fully austenitic microstructures at the solution treatment temperature 1050 degrees Celsius, and the indications are that the nitrogen is fully dissolved. The austenite stability of the alloys however varies at room temperature. Alloys containing approximately 5 wt% nickel, with a maximum nitrogen content of 0.28 wt%, contain up to 97% retained austenite, whereas alloys with 3.4 wt% nickel and the same maximum nitrogen content, contain only up to 63% retained austenite. DA - 1992 DB - ResearchSpace DP - CSIR KW - Nickel Nitrogen KW - Austenitic stainless steel KW - ISI 301 LK - https://researchspace.csir.co.za PY - 1992 T1 - The influence of nickel-nitrogen ratio on the deformation behaviour of austenitic stainless steels TI - The influence of nickel-nitrogen ratio on the deformation behaviour of austenitic stainless steels UR - http://hdl.handle.net/10204/6379 ER -