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Measurements of Secondary Phases Conten in a 22Cr5Ni Duplex Stainless Steel
No full textA duplex stainless steel (DSS) containing nominally 22Cr, 5Ni, 3.2Mo and 1.5Mn has been investigated for secondary phases precipitation, after ageing at 780, 850 and 900°C. Selective etching with different reagents, OM and SEM-BSE have been used to quantify ferrite, austenite and secondary phases. A critical discussion of different metallographic techniques (use of OM and/or SEM-BSE) applied to measure intermetallic content is presented, including an attempt to distinguish chi and sigma. The chemical composition of the phases has been determined by means of EDS, the effects on mechanical properties have been studied with a hardness test. The hardness increases with holding time for all temperatures. The rate of secondary phases increases with the holding time. The 850°C treatment is the most effective for increasing hardness and secondary phase precipitation. The SEM-BSE method seems to be more reliable than OM for measuring the secondary phase contents and for identifying chi and sigma
Modern Installations for the Continuous Process Induction Hardening and Tempering of Steel Bars
No full textInfluence of isothermal aging on secondary phases precipitation and toughness of a duplex stainless steel SAF 2205
No full textIn this paper the results of secondary phases determination in a SAF 2205 duplex steel, heat treated at 780, 850 and 900 °C for 10-40 min, are presented. χ-phase is the first phase to precipitate at all the temperatures, followed by σ-phase. The main drop of toughness is related to very low contents of χ-phase and σ-phase. Hardness is not a sensitive parameter to low amounts of secondary phases
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