Microstructure Evaluations in Pearlitic Steels Wires Resulting from Modification of the Interoperation Annealing Process

Pearlitic steels containing from some 0.8 to 0.95% C belong to the group of unalloyed steels of the quality class destined for cold drawing or rolling. At the same time, the steels are characterised with particularly low share of non-metallic inclusions and limited contents of chromium and nickel, which extend the pearlite reaction time. The pearlitic steel in the annealed state has the highest strength in relation to other unalloyed steels, therefore she have found application mainly as wire rods for springs, wires for car tire reinforcement and cables. However one of the issues widely discussed in literature is cracking of pearlitic steel subjected to plastic working, caused by high brittleness of the lamellar precipitations of hard cementite. This issue is extremely important because it affects significantly reduce fatigue strength. The paper presents proposals to modify the process of interoperation annealing in order to eliminate this problem.