Issue |
MATEC Web Conf.
Volume 269, 2019
IIW 2018 - International Conference on Advanced Welding and Smart Fabrication Technologies
|
|
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Article Number | 03009 | |
Number of page(s) | 7 | |
Section | Corrosion and Failure Analysis | |
DOI | https://doi.org/10.1051/matecconf/201926903009 | |
Published online | 22 February 2019 |
Analysis of Weld Cold Cracking In Excavator Bucket Adapter
1
Department of Metallurgy and Materials Engineering, Universitas Indonesia, Depok, Indonesia
2
PT Komatsu Indonesia, Jakarta, Indonesia
Corresponding author: winarto@metal.ui.ac.id
This paper presents a failure analysis on welding of bucket adapter for an excavator that made of low carbon steel with Ideal Diameter (DI) value 341 and Carbon Equivalent 0.73. The bucket component is stated OK as the final inspection, but four months later found cracked and even it has not been used yet. Adapter mounted to bucket through CO2 gas shielded Gas Metal Arc Welding (GMAW) process, filler metal MG-50 (AWS A5.18 ER70S-G), pre-heating and post-heating. Crack occurred on the boundary of weld metal and adapter casting. The metallurgical examination was conducted in the crack origin and the adapter casting. Nondestructive test (NDT) covered visual and magnetic test (MT), while destructive test (DT) covered fractography, mechanical properties, and Electron Probe Micro Analyzer (EPMA). The investigation resulted in that crack initiated from slag inclusion in the weld metal due to insufficient cleaning on weld joint. The higher hardness of martensite structure in the heat affected zone (HAZ) of adapter indicates high cooling rate that gen erates high residual stress. High stress that caused by insufficient post heating triggered severe crack propagation. By its characteristic, crack is called the cold cracking, delayed cracking, or hydrogen-induced cracking (HIC).
© The Authors, published by EDP Sciences, 2019
This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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