Effect of Austempering Go-Kart Rear Axle on Toughness Properties and Microstructure Morphology

Abstract

A Go-Kart is a four-wheeled vehicle that exhibits characteristics similar to a motorcycle. Additionally, since Go-Kartslack shock absorbers, it is crucial to use an engine that minimizes vibrations. The shaft, a typically circular rotating part, is oftenattached to elements like gears and endures continuous loads, which can lead to breakage. Shaft failures are common and often result from incidents caused by the need to use lightweight materials for faster performance. This study aims to examine the strength characteristics of the Go- Kart rear wheel shaft made from ASTM A414 Grade A steel after undergoing bending tests, impact tests, and microstructure analysis. Specifically, it investigates the effects of temperature on the toughness and curvature of the Go-Kart rear wheel shaft post-normalizing and tempering processes. Methods employed include heat treatment, three-point bending tests, Charpy impact tests, and ASTM E3-11 microstructure analysis. The highest impact value, 0.644joules/mm2, was observed in specimen B, which underwent a normalizing process at 850°C and tempering at 300°C. The lowest impact value, 0.190 joules/mm2, was found in specimen A, which underwent a normalizing process at 800°C and tempering at 250°C. The highest three-point bending strength, 2520.1 N/mm2, was also recorded in specimen B, while the lowest, 2255.4 N/mm2, was in specimen C, which underwent normalizing at 900°C and tempering at 350°C. Microstructure analysis revealed that higher temperatures during the normalizing and tempering processes result in the formation of more pearlite crystals and a denser microstructure.