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Impact and tensile properties of ferrite–martensite dual‐phase steels
Author(s) -
ISFAHANI T. DALALLI,
SHAFYEI A.,
SHARIFI H.
Publication year - 2009
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.2008.01318.x
Subject(s) - martensite , materials science , volume fraction , dual phase steel , microstructure , ultimate tensile strength , metallurgy , quenching (fluorescence) , ferrite (magnet) , toughness , annealing (glass) , composite material , physics , quantum mechanics , fluorescence
The effect of martensite morphology on the impact and tensile properties of dual phase steels with a 0.25 volume fraction of martensite ( V m ) under different heat treatments was investigated. These treatments are direct quenching (DQ) and step quenching (SQ) that result in different microstructures and mechanical properties. To process dual phase steels, a low carbon manganese steel was used. At first the banding present in the initial steel was eliminated, then the two different heat treatments were applied. To reach a 0.25 volume fraction of martensite a variation of intercritical annealing temperatures was adopted for both treatments that allowed the evolution of different volume fraction of martensite. Phase analysis showed that an intercritical temperature of 725 °C (between A 3 , A 1 ) gives the desired 0.25 V m of martensite. A comparison of impact, tensile and ductile–brittle transition temperature (DBTT) indicates that the microstructure of the direct treatment has a better toughness. The DBTT for the DQ and SQ treatment is −49 and −6 °C, respectively.