Influence of Heat Input on the Weldability of ASTM A131 DH36 Fillet Joints Welded by SMAW Underwater Wet Welding

Abstract

Naval vessels face multiple risks that can damage their hulls during navigation, leading to on-site repairs through the shield metal arc welding (SMAW) process and underwater wet welding (UWW). This paper presents a weldability study to identify the optimal heat input parameters to improve ASTM A131 DH36 welded joints quality, development, and sustainability. This study analyzes the influence of heat input on the microstructure and mechanical properties of underwater wet welding fillet joints welded with shield metal arc welding at 4 m water depth in a real-life environment located at the bay of Cartagena (Colombia). The methodology involves nondestructive and destructive tests, including visual inspection, fillet weld break, scanning electron microscopy (SEM), X-ray diffraction (XRD), Vickers hardness, and shear strength tests. The welds microstructure is composed of ferrite, pearlite, retained austenite, bainite, and martensite; the hardness values range from 170 HV1 to 443 HV1, and the shear strength values range from 339 MPa to 504 MPa. This indicates that high thermal inputs improve the weld quality produced by the underwater wet welding technique and can comply with the technical acceptance criteria of AWS D3.6, making them more sustainable, with less welding resources wastage and less impact on marine ecosystems.

Pengaruh Media Pendingin terhadap Kekerasan dan Struktur Mikro Hasil Pengelasan SMAW Pegas Daun Mitsubishi PS 120

“…Pegas merupakan suatu alat yang terbuat dari baja yang memiliki sifat elastisitas tinggi dan berfungsi sebagai penerima beban dinamis (Brandão, 2023;Fitriyus, 2023;Prasanna, 2023;Ranjan, 2023;González-Fernández, 2019;). Penggunaan pegas banyak ditemui dalam bidang teknik umumnya pada kendaraan bermotor, hal ini dikarenakan pegas memiliki peranan penting untuk memberikan kenyamanan terhadap pengguna kendaraan bermotor (Cortes, 2023;Romero, 2023;Wibowo, 2023;Ambade, 2022;Hariprasath, 2022). Pada kendaraan yang banyak menerima beban besar seperti truk, penggunaan pegas daun sangat cocok digunakan karena memiliki sifat elastisitas, modulus relesien yang bagus dan di imbangi dengan ketangguhan yang tinggi untuk menerima beban yang besar (Azwinur, 2022;Ghorbel, 2022;Than, 2022;Saxena, 2021;Sepe, 2021).…”