Analisis Post Weld Heat Treatment Dengan Proses Annealing Terhadap Kekuatan Sambungan Las Baja ST 40 Dengan Metode Las Zigzag dan Lurus

Abstract

This study aims to analyze the effect of Post Weld Heat Treatment (PWHT) through the annealing process on the strength of ST 40 steel weld joints using zigzag and straight welding methods. Welding generally induces residual stresses and microstructural changes, especially in the Heat Affected Zone (HAZ), which can compromise mechanical properties. To counteract these effects, post-weld annealing was performed to achieve a more uniform microstructure, relieve residual stresses, and consequently improve the mechanical properties of the joints. The research employed ST 40 steel specimens welded using the two path variations, with some subsequently subjected to annealing at 650⁰ C and holding time 90 minutes. The average tensile test results show that the zigzag specimen without PWHT annealing exhibited the highest modulus of elasticity, at 6,298.06 N/mm², and the zigzag specimen with PWHT annealing showed the lowest modulus of elasticity, at 4,913.56 N/mm².