Effect of plastic deformation on the formation of acicular ferrite

The effect of plastic deformation on the transformation of austenite to acicular ferrite in a Fe–Mn–Si–C alloy steel containing non-metallic inclusions was investigated. The transformation to acicular ferrite is retarded and the final fraction of acicular ferrite is reduced in plastically deformed austenite, which is a characteristic of a displacive transformation mechanism. The increase in the chemical driving force for transformation due to large undercooling below the Bs temperature overcomes the efficacy of dislocations in preventing the growth of acicular ferrite.