Recycling CK45 steel chips via spark plasma sintering: Enhanced mechanical and corrosion properties

This study investigates the impact of coolant application during the turning of CK45 steel shafts on their mechanical, wear, and corrosion properties. Samples were machined at a cutting depth of 0.5 mm under two conditions using a water-based emulsion coolant and without coolant, and compared to untreated (as-received) material. Results demonstrated that coolant usage substantially improved material performance: hardness increased by 38% (from 218 to 301 HV), compressive strength rose by 31% (from 750 to 984 MPa), and wear resistance was enhanced by 82%, with weight loss due to wear decreasing from 18.51 to 3.32 mg. Furthermore, corrosion resistance improved by 87%, as the corrosion rate was reduced from 0.077 to 0.01 mm/year. These significant improvements, achieved through coolant-assisted machining and subsequent SPS processing of CK45 chips, present a novel, sustainable approach to enhancing steel component performance. Unlike previous studies that focused only on machining parameters or post-processing effects, this work combines chip recycling with controlled thermal-mechanical treatment. This integrated approach improves mechanical strength, wear resistance, and corrosion behavior at the same time. It also offers a scalable and sustainable strategy for producing high-performance components with lower environmental and material costs.