Effect of annealing between cold working and quenching on the structure and properties of steel

Abstract

Substantial improvement in the properties of metals may be achieved by the modification of the fibre structure in a forming operation, and a further improvement is gained by the inheriting of the structural changes caused by both hot or cold mechanical working. These effects are utilized, for example, in the thermo-mechanical treatments (TMT): high-TMT, low-TMT and iso-TMT. Such treatments have recently become well understood and are now frequently applied in industry as routine processes. However, the advantages of work hardening of ferrite have not been investigated as closely.The present study examines the qualitative influence of work hardening of ferrite on the properties of steel after quenching. Results show that work hardening of ferrite, and particularly the employment of particular annealing temperatures after cold work, have a beneficial influence on the properties and structure of steel, observed after its quenching. Investigations of a plain carbon steel and of a high-speed tool steel (T7) show that annealing within the ranges 250 to 350°C and 450 to 500°C results in an improvement in hardness and structure of the steels.