STUDIES ON KINETICS OF STRAIN AGING IN NB, TI, V-BEARING HSLA STEELS AND A DUAL-PHASE STEEL

Strain-ageing behaviour of different high-strength low-alloy (HSLA) and dual-phase steels was investigated. Single factor experiments were carried out to decide on the range of variation of variables for construction of the matrix of experimental design. Quantitative relationships between time and temperature of ageing (within a narrow range) at constant pre-strain, with increase of yield strength after strain ageing was developed in the form of regression equations by applying statistical design of experiments. Validity of these equations was checked by statistical method as well as by random experiments. Activation energies for strain ageing of these steels were determined by using the developed regression equations. These values were in close agreement with the values reported by other investigators.