"Development of Optimum Heat Parameters in Manufacturing of C-80 Spring Steel Circlips"

Steels with large chromium and vanadium percentage can be used as spring steels which form the suspension system. Prevention of wear and increase in steel life depends principally on the design and operation of the component, but providing some pre-use treatment on steel can also improve the quality to a great extent. It has been seen that most of the study focuses on the experimental testing of the steel component, and very few focuses on the material testing and improving its properties beforehand. One of the processing routes to alter the properties is heat treatment. Nearly 90% of the springs are used in heattreated conditions. The primary requirement for conventional spring steel is toughness, strength & hardness. In this view, it is proposed to study the mechanical properties of C-80 spring steel with extra heat (thermal) treatments like normalizing, hardening and tempering. All heat treatments are carried out in atmospheric conditions. Hardening treatment improves the hardness of the material, a marginal decrease in hardness value with improved ductility is observed in tempering. Hardening and longer duration tempering show better wear resistance compare to other heat treatments. Both mild and severe wear regions are observed. The mechanical properties (tensile yield strength, ultimate tensile strength, Young’s modulus, percentage reduction, percentage elongation, toughness, resilience and hardness) of the treated and untreated samples were determined using standard methods, and the mechanical properties valid for the cycle-time were noted. Results showed that the mechanical properties of C-80 Spring steel could be changed and improved by various heat treatments for a particular application in die-holders for horizontal extrusion. It was also found that the annealed samples with a hardening temperature of 825°C and oil quenched at 60°C, which was further tempered for 3 hours at 400°C had sustained for the most extended period as it had the highest resilience that allowed it to come back to its original shape irrespective of the high temperatures in the process.