Premium
Tempering behaviour of a dual‐phase low‐alloy steel
Author(s) -
Panda Ashok Kumar,
Sarma Dharba Subhramanya,
Ganguly Ratan Indu,
Misra Somnath
Publication year - 1993
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199301563
Subject(s) - tempering , martensite , metallurgy , materials science , dual phase steel , ultimate tensile strength , equiaxed crystals , elongation , alloy , bainite , microstructure
The tempering behaviour of a dual phase steel of 0.08% C, 1.21% Mn, 1.00% Si, 0.42% Cr, and 0.41% Mo composition with two different martensite contents of 30 and 52%. (obtained by intercritical treatments at 820 and 860°C, respectively) has been studied. The ultimate tensile strength decreased and percentage elongation increased continuously with increasing tempering temperature up to 600°C for both intercritical treatments. The yield strength has, however, increased up to 300°C, beyond which it decreased for the steel with 30% martensite. In contrast it remained almost constant for 52% martensite up to 300°C, beyond which it decreased. The martensite of dual‐phase steel for both the intercritical treatments has undergone microstructural changes on tempering that are akin to those of fully martensitic low carbon steels. The SEM fractographs from the as‐quenched specimens indicate that the tensile specimens failed by microvoid coalescence with the martensite areas appearing facetted and featureless while those for 600°C tempered condition by the formation of equiaxed dimples.