PSI - Issue 27

Eko Surojo et al. / Procedia Structural Integrity 27 (2020) 14–21 Surojo et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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selection of appropriate topics is referred. Table 1 summarizes some research articles about metallic materials use in underwater welding.

Table 1. Research articles about underwater welding of metallic material. No. Scholars Material Method

Findings

Microstructure

Mechanical Properties

1.

Liu et al. (2010)

2219 Aluminum Alloy

friction stir welding

The refined grain structures, high-density dislocations and enhance solid solution strength effect synthetically led to the increase of hardness of MHL, and thus improved the tensile strength of the underwater joint. NHAZ area forms deposits with a diameter of 106 ± 28nm with a thickness of 10 ± 2.6nm while deposits in the UHAZ area have 92 ± 30 and 7±1.8nm diameters. In the HAZ area, there are a lot of lath bainite and a few Acicular Ferrite, polygonal ferrite, and martensite. The underwater structure is more dominant in the form of regular Ferrite Granules. It due to the rapid cooling of UWW The fraction of the void area in the SZ of underwater FSW is decreases in a higher number than normal FSW. It is diminished 3.6% in the SZ of normal FSW and 1.3% in the underwater FSW stir zone. The size of recrystallized grains was approximately 2.26μm and 2.33μm whereas, in 0°C water, the size of recrystallized grains decreased to 1.20μm and 1.23μm for the hot band and annealed hot band. There are many microstructures of Lath Martensite with different types that dominate the CGHAZ area.  Air welding is dominated by Polygonal Ferrite (PF) and grain boundary ferrite (GBF) phases. UWW with a depth of 2.5m is dominated by GBF and PF, while depths of 5and 10m are dominated by AF and FSP (Ferrite with Second Phase-aligned).

The tensile strength of the normalized material is 315MPa, and after underwater welding process is 341MPa.

2.

Zhang et al. (2012)

2219-T6 Aluminum Alloy

friction stir welding

The minimum hardness value of UHAZ (Underwater HAZ) is 92HV, while NHAZ (Normal HAZ) is 78HV. Maximum tensile strength and impact energy at V-notch found 500MPa and 39.5J in welded joints with 45kN axial force Longitudinal tensile strength at the average yield strength is 475MPa, and the ultimate strength is 577MPa. The average hardness of underwater FSW increases 21% greater than the normal FSW, and 53% greater than its Base Material (BM). The fracture morphology was constituted of a large number of deep dimples. When the annealed hot band was welded in 0°C water, the fracture morphology was a large number of shallow dimples whereas, in air condition, the depth of the dimples gradually increased. Ultimate tensile strength and impact strength increase during the process of a solid solution, due to many alloying elements (e.g., Fe, Mn, and Cr). Weld metal on UWW joints at a depth of 10m has a higher hardness value of around 365HV. There are many structures of AF (Accicular Ferrite) caused by rapid cooling.

3.

Cui et al. (2014)

S355 steel

friction taper plug welding

4.

Baillie et al. (2015)

S275 steel

friction stir welding

5.

Pedapati et al. (2017)

5052 aluminum alloy

friction stir welding

6.

Tan et al. (2017)

AA 3003 aluminum alloy

friction stir welding

7.

Li et al. (2018)

E40 Steel

flux-cored arc welding

shielded metal arc welding

8.

Muhayat et al. (2020)

Low carbon steel SS400