A Study on the Relationship Between the Microstructure, Tensile Stress, and I-Section Width in Thin-Walled Spheroidal Graphite Iron Connecting Rods

Abstract

Automotive components must be lighter to reduce fuel consumption. Component production must prioritize energy efficiency and environmental sustainability. Aluminium is characterized by its lightweight properties; however, its production is energy intensive. Spheroidal graphite iron provides significant design flexibility, and the use of thin wall casting can reduce its weight, enabling competition with less weight components. The development of a 2 mm I-section width connecting rod that satisfies previous research criteria has prompted further exploration into the reduction of I-section width. These boosts connecting rod weight reduction. This effort seeks to achieve repeatability in 2 mm I-section width design and capability to generate 1.5 mm I-section width via casting design. Thin wall casting solidification rates are important owing to product widths. It also examines I-section width and tensile stress. Foundry size I-sections were 2 mm and 1.5 mm thick. The microstructure and tensile load of all I-sections were characterized. Tensile testing assessed tensile load. Microstructure observations indicated that the I-section microstructure differs from that of the big end microstructure, except for unique casting location. Meanwhile, the tensile load demonstrated comparable mean tensile load between 2 mm and 1.5 mm, aligning with the requirements for connecting rod tensile loads. This work created casting models for making equivalent-load thin wall spheroidal graphite iron (TWSG) connecting rods.