scholarly journals Process Stability, Microstructure and Mechanical Properties of Underwater Submerged-Arc Welded Steel

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1249
Author(s):  
Maofu Zhang ◽  
Yanfei Han ◽  
Chuanbao Jia ◽  
Shengfa Dong ◽  
Sergii Maksimov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Water Glass ◽  
Welding Process ◽  
Process Stability ◽  
Surrounding Water ◽  
Welded Steel ◽  
Underwater Wet Welding ◽  
Marine Engineering ◽  
High Level

In underwater wet welding, the unstable welding process caused by the generation and rupture of bubbles and the chilling effect of water on the welding area result in low quality of welded joints, which makes it difficult to meet the practical application of marine engineering. To improve the process stability and joining quality, a mixture of welding flux with a water glass or epoxy resin was placed on the welding zone before underwater welding. In this paper, welds’ appearance, geometry statistics of welds’ formation, welding process stability, slag structure, microstructure, pores and mechanical properties were investigated. It was found that with the addition of water glass in the mixture, the penetration of weld was effectively increased, and the frequency of arc extinction was reduced. Though the porosity rose to a relatively high level, the joints’ comprehensive mechanical properties were not significantly improved. Notably, the applied epoxy resin completely isolated the surrounding water from the welding area, which greatly improved process stability. Furthermore, it benefited from the microstructure filled with massive acicular ferrite, the average elongation and room temperature impact toughness increased by 178.4%, and 69.1% compared with underwater wet welding, respectively, and the bending angle of the joint reaches to 180°.

Correlation between wire feed speed and external mechanical constraint for enhanced process stability in underwater wet flux-cored arc welding

2018 ◽  
Vol 233 (10) ◽  
pp. 2061-2073 ◽  
Author(s):  
Jianfeng Wang ◽  
Qingjie Sun ◽  
Jiangkun Ma ◽  
Peng Jin ◽  
Tianzhu Sun ◽  
...  
Keyword(s):  
Welding Process ◽  
Electrical Signal ◽  
Feed Speed ◽  
Process Stability ◽  
Underwater Wet Welding ◽  
Extinction Process ◽  
Flux Cored Arc Welding ◽  
Wire Feed Speed ◽  
Wire Feed ◽  
Mechanical Constraint

It is a great challenge to improve the process stability in conventional underwater wet welding due to the formation of unstable bubble. In this study, mechanical constraint method was employed to interfere the bubble generated by underwater wet welding, and the new method was named as mechanical constraint assisted underwater wet welding. The aim of the study was to quantify the combined effect of wire feed speed and condition of mechanical constraint on the process stability in mechanical constraint assisted underwater wet welding. Experimental results demonstrated that the introduction of mechanical constraint not only suppressed the bubble without floating but also stabilized the arc burning process. The degree of influence of mechanical constraint, which changed with wire feed speed, played an important role during the mechanical constraint assisted underwater wet welding process. For all wire feed speeds, the fluctuations of welding electrical signal were decreased through introduction of mechanical constraint. The difference in the proportion of arc extinction process between underwater wet welding and mechanical constraint assisted underwater wet welding became less with increasing wire feed speed. At wire feed speed lower than 7.5 m/min, the improvement of process stability was very significant by mechanical constraint. However, the further improvement produced limited effect when the wire feed speed was greater than 7.5 m/min. The observation results showed that a better weld appearance was afforded at a large wire feed speed, corresponding to a lower variation coefficient.

The effect of alumino-thermic addition on underwater wet welding process stability

2017 ◽  
Vol 245 ◽  
pp. 149-156 ◽  
Author(s):  
H.L. Li ◽  
D. Liu ◽  
N. Guo ◽  
H. Chen ◽  
Y.P. Du ◽  
...  
Keyword(s):  
Welding Process ◽  
Process Stability ◽  
Underwater Wet Welding

Internal characteristic of droplet and its influence on the underwater wet welding process stability

2020 ◽  
Vol 280 ◽  
pp. 116593 ◽  
Author(s):  
Changsheng Xu ◽  
Ning Guo ◽  
Xin Zhang ◽  
Hao Chen ◽  
Yunlong Fu ◽  
...  
Keyword(s):  
Welding Process ◽  
Process Stability ◽  
Underwater Wet Welding ◽  
Internal Characteristic

Influence of calcium fluoride on underwater wet welding process stability

2018 ◽  
Vol 63 (1) ◽  
pp. 107-116 ◽  
Author(s):  
Ning Guo ◽  
Changsheng Xu ◽  
Yongpeng Du ◽  
Hao Chen ◽  
Yunlong Fu ◽  
...  
Keyword(s):  
Calcium Fluoride ◽  
Welding Process ◽  
Process Stability ◽  
Underwater Wet Welding

Analysis and improvement of underwater wet welding process stability with static mechanical constraint support

2018 ◽  
Vol 34 ◽  
pp. 238-250 ◽  
Author(s):  
Jianfeng Wang ◽  
Qingjie Sun ◽  
Yunlu Jiang ◽  
Tao Zhang ◽  
Jiangkun Ma ◽  
...  
Keyword(s):  
Welding Process ◽  
Process Stability ◽  
Underwater Wet Welding ◽  
Static Mechanical ◽  
Mechanical Constraint

Effects of bottom plate in friction stir welding of AA6061-T6

2020 ◽  
Vol 118 (1) ◽  
pp. 108
Author(s):  
M.A. Vinayagamoorthi ◽  
M. Prince ◽  
S. Balasubramanian
Keyword(s):  
Mechanical Properties ◽  
Axial Load ◽  
Weld Zone ◽  
Welding Process ◽  
Bottom Plate ◽  
Welding Parameters ◽  
Nugget Zone ◽  
Friction Stir ◽  
Weld Joints ◽  
Fine Grain

The effects of 40 mm width bottom plates on the microstructural modifications and the mechanical properties of a 6 mm thick FSW AA6061-T6 joint have been investigated. The bottom plates are placed partially at the weld zone to absorb and dissipate heat during the welding process. An axial load of 5 to 7 kN, a rotational speed of 500 rpm, and a welding speed of 50 mm/min are employed as welding parameters. The size of the nugget zone (NZ) and heat-affected zone (HAZ) in the weld joints obtained from AISI 1040 steel bottom plate is more significant than that of weld joints obtained using copper bottom plate due to lower thermal conductivity of steel. Also, the weld joints obtained using copper bottom plate have fine grain microstructure due to the dynamic recrystallization. The friction stir welded joints obtained with copper bottom plate have exhibited higher ductility of 8.9% and higher tensile strength of 172 MPa as compared to the joints obtained using a steel bottom plate.

Effect of Epoxy Resin Concentration on Some Mechanical Properties of Carbon Fabric/ Nitrile Rubber Reinforced Composites

2019 ◽  
Vol 9 (1) ◽  
pp. 1-15
Author(s):  
Sawsan Fakhry Halim ◽  
Said Sayed Gad El Kholy ◽  
HalaFikry Naguib ◽  
Riham Samir Hegazy ◽  
Nermen Mohamed Baheg
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Nitrile Rubber ◽  
Reinforced Composites ◽  
Carbon Fabric

The Mechanical Properties of Organic Modified Epoxy Resin

2020 ◽  
Vol 43 (3) ◽  
pp. 10-14
Author(s):  
Georgel MIHU ◽  
Claudia Veronica UNGUREANU ◽  
Vasile BRIA ◽  
Marina BUNEA ◽  
Rodica CHIHAI PEȚU ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Epoxy Resin ◽  
Epoxy Matrix ◽  
Epoxy Resins ◽  
Mechanical Tests ◽  
Organic Modification ◽  
Three Point Bending ◽  
Modified Epoxy

Epoxy resins have been presenting a lot of scientific and technical interests and organic modified epoxy resins have recently receiving a great deal of attention. For obtaining the composite materials with good mechanical proprieties, a large variety of organic modification agents were used. For this study gluten and gelatin had been used as modifying agents thinking that their dispersion inside the polymer could increase the polymer biocompatibility. Equal amounts of the proteins were milled together and the obtained compound was used to form 1 to 5% weight ratios organic agents modified epoxy materials. To highlight the effect of these proteins in epoxy matrix mechanical tests as three-point bending and compression were performed.

Sign in / Sign up

Export Citation Format

Share Document