Experimental Study on Bead on Plate (BOP) Welding of 6 mm Thick 9% Nickel Steel by Fiber Laser Welding

Nine percent nickel steel has excellent properties in a cryogenic environment, so it has recently been used as a tank material for most LNG fuel-powered ships. However, 9% nickel steel causes arc deflection due to its tendency of magnetization during manual FCAW welding and the currently used filler metal is 10–25 times more expensive as a base metal compared to other materials, depending on manufacturers. Furthermore, the properties of its filler metal cause limitation in the welding position. To overcome these disadvantages, in this study, the tendency of penetration shape was analyzed through a fiber laser Bead on Plate (BOP) welding for 9% nickel steel with a thickness of 6 mm and a range of welding conditions for 1-pass laser butt welding of 6 mm thick 9% nickel steel with I-Groove were derived. Through this study, basic data capable of deriving optimal conditions for laser butt welding of 9% nickel steel with a thickness of 6 mm were obtained.

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Multi-stage keyhole evolution in fiber laser welding: an experimental study and theoretical analysis

Results in Physics ◽

10.1016/j.rinp.2021.104943 ◽

2021 ◽

pp. 104943

Author(s):

Shihui Guo ◽

Jianglin Zou ◽

JieJie Xu ◽

Qiang Wu ◽

Rongshi Xiao

Keyword(s):

Experimental Study ◽

Theoretical Analysis ◽

Laser Welding ◽

Fiber Laser ◽

Fiber Laser Welding ◽

Multi Stage

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A Study on Welding Deformation in Fiber Laser Welding of 9% Nickel Steel through Finite Element Analysis Part I: Implementation of Welding Heat Source Model

Processes ◽

10.3390/pr9122188 ◽

2021 ◽

Vol 9 (12) ◽

pp. 2188

Author(s):

Changmin Pyo ◽

Jaewoong Kim ◽

Du-Song Kim

Keyword(s):

Natural Gas ◽

Heat Source ◽

Laser Welding ◽

Fiber Laser ◽

Source Model ◽

Heat Transfer Analysis ◽

Welding Deformation ◽

Nickel Steel ◽

Fiber Laser Welding ◽

Heat Source Model

Due to various environmental regulations, the demand for natural gas, i.e., a clean energy, is expected to increase continuously. In terms of efficient storage and transportation of natural gas, liquefied natural gas has an advantageous volume of 1/600 compared to natural gas, but the materials that can be used at a cryogenic temperature of −163 °C are limited. A 9% nickel steel is a material recommended by IMO through IGC. It has excellent mechanical properties compared to other cryogenic materials, but its use has been limited due to its disadvantages in arc welding. Therefore, the main topic of this study is the automatic welding of 9% nickel steel using fiber laser and its purpose is to predict the welding deformation during fiber laser welding. First, an investigation was conducted to find the fiber laser welding heat source. A model that can cover all the models in prior studies such as curve, exponential, conical, conical-conical combination, and conical-cylinder combination models was proposed and the heat source model was constructed in a multi-layer format. Heat transfer analysis was performed using the ratio of a heat source radius and heat energy of each layer as a variable and the pass or failure of a heat source was determined by comparing the analysis results to the experimental results. By changing the variables in conjunction with the optimization algorithm, the main parameters of a passed heat source model were verified in a short period of time. In addition, the tendency of parameters according to the welding speed was checked.

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Experimental study on weld formation of Inconel 718 with fiber laser welding under reduced ambient pressure

Vacuum ◽

10.1016/j.vacuum.2018.02.008 ◽

2018 ◽

Vol 151 ◽

pp. 140-147 ◽

Cited By ~ 9

Author(s):

Liqun Li ◽

Genchen Peng ◽

Jiandong Wang ◽

Jianfeng Gong ◽

Huizhi Li

Keyword(s):

Experimental Study ◽

Laser Welding ◽

Fiber Laser ◽

Inconel 718 ◽

Ambient Pressure ◽

Fiber Laser Welding ◽

Weld Formation

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A Study on the Algorithm of Quality Evaluation for Fiber Laser Welding Process of ASTM A553-1 (9% Nickel Steel) Using Determination of Solidification Crack Susceptibility

Materials ◽

10.3390/ma13245617 ◽

2020 ◽

Vol 13 (24) ◽

pp. 5617

Author(s):

Minho Park ◽

Jisun Kim ◽

Changmin Pyo ◽

JoonSik Son ◽

Jaewoong Kim

Keyword(s):

Welding Process ◽

Optimization Procedure ◽

Nickel Steel ◽

Cryogenic Temperatures ◽

Fiber Laser Welding ◽

Materials Used ◽

Lng Fuel ◽

Crack Susceptibility ◽

Cryogenic Tanks ◽

Solidification Crack

To prevent the contamination of the marine environment caused by ship exhaust gas, the demand for LNG (liquefied natural gas) fueled ships is increasing worldwide. A tank to store LNG at cryogenic temperatures is indispensable to such LNG-fueled ships. Since the materials used for LNG fuel propulsion tanks must have excellent mechanical properties such as impact toughness at cryogenic temperatures, the International Maritime Organization limits the IGC Code only to four types. Most of the tank materials for LNG-fueled ships ordered recently are adopting ASTM A553-1 material, but a systematic study to analyze the problem of quality degradation that may occur when welding A553-1 steel is required to secure the safety of cryogenic tanks. Therefore, in this study, among various quality problems, the tendency of weld solidification crack vulnerability is identified, and a decision system and optimization procedure are developed. In addition, a method of securing the welding quality of A553-1 steel was proposed by setting quality deterioration standards.

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Evaluation of the effect of filler metal interlayer on the weld joint quality in fiber laser welding of alloy steel (A516)

Journal of Laser Applications ◽

10.2351/7.0000580 ◽

2022 ◽

Vol 34 (1) ◽

pp. 012011

Author(s):

Adnan I. Khdair ◽

Ahmed B. Khoshaim ◽

Khaled A. Alnefaie

Keyword(s):

Laser Welding ◽

Fiber Laser ◽

Alloy Steel ◽

Weld Joint ◽

Filler Metal ◽

Fiber Laser Welding ◽

Joint Quality

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Distribution of Al Element of Ti–6Al–4V Joints by Fiber Laser Welding

Coatings ◽

10.3390/coatings9090566 ◽

2019 ◽

Vol 9 (9) ◽

pp. 566 ◽

Cited By ~ 2

Author(s):

Jiajia Zhang ◽

Renzhi Hu ◽

Shengyong Pang ◽

Anguo Huang

Keyword(s):

Laser Welding ◽

Fiber Laser ◽

Molten Pool ◽

Fiber Laser Welding ◽

Butt Welding ◽

Solute Element ◽

Self Diffusion ◽

The Difference ◽

Joint Quality

In the process of laser welding, the uneven distribution of solute elements caused by element burning loss and flow of molten pool affects the quality of joints. In this paper, butt welding experiments were conducted on the 3 mm thick Ti–6Al–4V specimens with different preset ratios of Al and Si powders by using 4 kW fiber laser. The distribution of Al solute element and its influence on the microstructure and mechanical properties of the final weld joint were investigated. The results showed that the self-diffusion of Al element and the flow of molten pool affects the alloy elements distribution in laser welding. And the microhardness of the welded joint with Ti–6Al–4V and 90% Al + 10% Si powders was significantly higher than that with only Ti–6Al–4V, with the difference of about 130HV. At the same time, in the joint with 90% Al and 10% Si powders, the acicular α’ size was finer, and basketweave microstructure was present as well. This research is helpful to better understand the distribution of Al solute element and its influence on the joint quality during laser welding of Ti–6Al–4V alloy, which provides a certain reference for improving the weld or surface properties of Ti–6Al–4V alloy during laser processing.

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