Optimizing Flexibility in SUP9 Leaf Springs: The Synergistic Effect of Tempering Temperature and Holding Time

Kris Witono; Lisa  Agustriyana; Sugeng Hadi Susilo

doi:10.51278/ajse.v4i1.1886

Authors

Kris Witono State Polytechnic of Malang
Lisa Agustriyana State Polytechnic of Malang
Sugeng Hadi Susilo State Polytechnic of Malang

DOI:

https://doi.org/10.51278/ajse.v4i1.1886

Keywords:

SUP9 Steel, Leaf Spring, Flexibility, Tempering Process, Heat Treatment, Mechanical Properties

Abstract

This study investigates the influence of tempering temperature and holding time on the flexibility of SUP9 steel leaf springs, addressing a practical need for enhanced vibration absorption in heavy-duty vehicles operating on irregular terrain. An experimental study was conducted using a full factorial design with three temperature levels (450°C, 550°C, 650°C) and three holding times (15, 20, 25 minutes). Flexibility was quantified by measuring the maximum deflection in a three-point bending test. The results demonstrate a strong, positive correlation between the tempering parameters and flexibility. The optimal flexibility (47.76 mm deflection) was achieved at the highest treatment condition of 650°C with a 25-minute holding time, representing an 83% improvement over the least effective treatment. ANOVA results confirmed that temperature, holding time, and their interaction are all statistically significant factors (p < 0.05). These findings provide a practical, data-driven guideline for manufacturing more resilient and comfortable leaf springs by optimizing heat treatment protocols.

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