The tensile strength of the grain coarsened HAZ was always higher than that of base metal, but yield strength was lower than that of base metal at cooling rates, t_8/5>60.
The strain hardening exponent, n, is reduced with increasing cooling rates ...
The tensile strength of the grain coarsened HAZ was always higher than that of base metal, but yield strength was lower than that of base metal at cooling rates, t_8/5>60.
The strain hardening exponent, n, is reduced with increasing cooling rates and this is due to formation of martensite with high dislocation density. In slower cooling rates, the formation of ferrite side plates gives rise to a substantial increase in the strian hardenability.