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    Effect of Heat Treatment on the High Cycle Fatigue Behaviour of S2205 Duplex Stainless Steels
    (Elsevier Ltd, 2017) Shamanth, V.; Kumar, P.; Ravishankar, K.S.
    This paper deals with the effect of heat treatment on the high cycle fatigue behavior of duplex stainless steels. In this investigation the specimens were annealed, aged, reversion heat treated and re-aged for varying periods. The results obtained showed that the microstructure plays an important role in the change in fatigue lives. The fatigue resistance was high in the aged and re-aged heat treated condition because of the presence of alpha, alpha prime and some molybdenum rich chromium nitride precipitates in their ferrite matrix. While in the annealed and reversion heat treated condition the samples were free from the precipitates and also there was no much difference in the hardness values of austenite and ferrite phases, hence there was a significant change in their fatigue lives when compared to that of the embrittled samples. © 2017 Elsevier Ltd.
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    Dissolution of alpha-prime precipitates in thermally embrittled S2205-duplex steels during reversion-heat treatment
    (Elsevier, 2015) Shamanth, V.; Ravishankar, K.S.
    Duplex stainless steels offer an attractive combination of strength, corrosion resistance and cost. In annealed condition duplex steels will be in thermodynamically metastable condition but when they are subjected to intermediate homologous temperature of ~475. °C and below significant embrittlement occurs, which is one of the key material degradation properties that limits its upper service temperature in many applications. Hence the present study is aimed to study the effect of reversion heat treatment and its time on mechanical properties of the thermally embrittled steel. The results showed that 60. min reversion heat treated samples were able to recover the mechanical properties which were very close to annealed properties because when the embrittled samples were reversion heat treated at an elevated temperature of 550. °C which is above the (?. +. ?') miscibility gap, the ferritic phase was homogenized again. In other words, Fe-rich ? and Cr-rich ?' prime precipitates which were formed during ageing become thermodynamically unstable and dissolve inside the ferritic phase. © 2015 The Authors.