Surface carburised AISI 8620 steel with dual phase core microstructure

Abstract

In this study, the production of dual phase steel structure in the core of surface carburised AISI 8620 cementation steel and the effect of martensite volume fraction on tensile properties have been investigated. For these purposes, surface carburised ( ~0. 8 wt-%C) specimens were oil quenched from 900°C to obtain a fully martensitic starting microstructure. Then specimens were oil quenched from intercritical annealing temperatures of 731 or 746°C to produce dual phase steel structure in the core of specimens with martensite fractions of ~25 or ~50 vol.-% and nearly wholly martensitic microstructure at the surface. Generally, specimens with dual phase microstructure in the core exhibited slightly lower tensile and yield strengths but superior ductility without sacri® cing surface hardness than those specimens with fully martensitic microstructure in the core produced by using conventional heat treatment involving quenching from 850 to 950°C. Also tensile strength increased and ductility decreased with increasing martensite volume fraction.MST/5119

Corrosion behavior of tempered dual-phase steel embedded in concrete

“…On the other hand, it is observed on these micrographs that the volume fraction of the martensite phase increases with an increase in the duration of austenization. A similar relationship has also been reported by other researchers [20][21][22][23][24][25][29][30][31][32] The changes in the volume fraction and grain size of the phases are given in Table 3. The increase in the volume fraction of martensite depends on the increase in austenization duration, which results in increasing the amount of austenite [20,33].…”

Effect of aging temperature and martensite by volume on strain aging behaviour of dual phase steel

“…It is seen that the volume of martensite and martensite grain sizes increased with the increase in intercritical annealing temperature; similar relationship has also been reported by other researchers. 6,9,[12][13][14] As seen in Fig. 1, the martensite islands are located in the ferrite grain boundaries.…”