Low–carbon Steels: the Calculation of Mixed–microstructures & Their Mechanical Properties

Steels are being designed with ever decreasing interstitial contents. At the same time, processing technology allows accelerated cooling without excessive distortion or microstructural gradients [1–5]. Lean steels with lower ‘carbon equivalents’ can therefore be manufactured, making fabrication relatively easy. Alloys such as these give uniform microstructures in spite of solidfication–induced chemical segregation. Segregated microstructures are more susceptible to stress–corrosion and hydrogen–induced cracking. This paper has a discussion of some difficulties in dealing with transformations in low–carbon steels, and of aspects of the mechanical properties of mixed microstructures.