PSI - Issue 27

Ericha Dwi Wahyu Syah Putri et al. / Procedia Structural Integrity 27 (2020) 54–61 Putri et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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consisted of Proeutectoid Ferrite, Side Plates of Ferrite, and Acicular Ferrite. Many inclusion in underwater welding is also measured the welding process. If the speed welding increase, the inclusion increase in the weld metal. The higher mechanical properties between strength and toughness found in WC10 samples where the given heat input is 10.0kJ/cm with conditions meeting t 8/5 at 8.6seconds. It causes a result of the increased process so that the structure of acicular ferrite is formed in large quantities in the weld metal. The cooling rate of UWW can make ferrite structures difficult to form, so the structure formed is Martensite. The martensite structure content in the UWW joint is susceptible to fatigue failure in the Base Metal Columnar microstructure in weld metal contains some FS (A) (Ferrite with second phase-aligned) and GBF (grain boundary ferrite), as well as a small portion of PF (Polygonal Ferrite) and AF (Acicular Ferrite) In the CGHAZ (coarse grain heat affected zone) area, the microstructure dominated by Lath Martensite which caused cold cracking. The difference in cooling rate on land and underwater caused differences in the microstructure. In the HAZ area, the microstructure formed by Martensite based on the structure PF. The bubbles produced by the arc weld cause an adverse effect on the stability of the welding and changes in the microstructure of the underwater welding joint. The depth of the water caused the formation of microstructure grains were fine. If the water depth is increased water depth, grain size will decrease due to occur increased the cooling rate. Moreover, the hardness material will increase. The depth of water also produces defects e.g. porosity and cracking. The increasing depth of the water the oxygen and hydrogen gas content will increase. In the CGHAZ (coarse grain heat affected zone) area, the Q235 steel welded joint has a microstructure consisting of WF (Widmanstatten Ferrite) and there is a small amount of LB (Lower Bainite), while the E40 steel welding joint contains many LM (Lath Martensite) and AM (Accicular Martensite). It can be a potential for the appearance of cold cracks because there are many Martensite structures that are easy to brittle.

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Sun et. al. (2016)

Microstructure Mechanical Properties of Ultrasonic Assisted Underwater Wet Welding Joints and

Evolution microstructure

4.

Gao et al. (2016)

Microstructural mechanical performance of underwater wet welded S355 steel and

Evolution microstructure

5.

Zhang et al. (2016)

Heat input and metal transfer influences on the weld geometry and microstructure during underwater wet FCAW

Evolution microstructure

6.

Wang et al. (2018)

Characterization of the underwater welding arc bubble through a visual sensing method Effect of Water Depth on the Microstructure and Mechanical Properties of SS400 Steel in Underwater Welding

Evolution microstructure

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Yohanes et al. (2020)

Evolution microstructure and defects

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Chen et al. (2020)

Effect of water flow on the microstructure, mechanical performance, and cracking susceptibility of underwater wet welded Q235 and E40 steel

Evolution microstructure and defects