DOI: https://doi.org/10.55373/mjchem.v27i3.509

Keywords: Crankpin; low carbon steel; alloy steel; mild steel; crankshaft

Abstract

Crankpin is a critical component in internal combustion engines, often fail due to low hardness, high operational temperatures, and inadequate lubrication. Conventional low-carbon steel crankpins are prone to such issues. This study aims to improve crankpin performance by replacing existing materials with 16MnCr5 steel, a low-carbon alloy hardened through case hardening in a sealed quench furnace. The methodology includes material preparation, case hardening, and subsequent evaluation via hardness testing and microstructure analysis. The hardened 16MnCr5 exhibited a surface hardness of 62–63 HRC, core hardness of 40–41 HRC, and an effective case depth of 1.34 mm. Microstructural analysis revealed fine tempered martensite with 2% retained austenite. These findings establish 16MnCr5 as a viable crankpin material and provide a reference for future comparisons with SCM420H and EN1A. Future work will further validate this selection through similar treatment and analysis of the additional materials.