scholarly journals A Study on Fiber Laser Welding of High-Manganese Steel for Cryogenic Tanks

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1536
Author(s):  
Jaewoong Kim ◽  
Jisun Kim ◽  
Changmin Pyo

As the environmental regulations on ship emissions by the International Maritime Organization (IMO) become stricter, the demand for a ship powered by liquefied natural gas (LNG) is rapidly increasing worldwide. Compared to other materials, high-manganese steel has the advantages of superior impact toughness at cryogenic temperatures, a low thermal expansion coefficient, and a low-cost base material and welding rod. However, there is a limitation that the mechanical properties of a filler material are worse than those of a base material that has excellent mechanical properties. To solve these shortcomings, a basic study was performed to apply fiber laser welding with little welding deformation and no filler material to high-manganese steel. The relationship between laser welding parameters and penetration shapes was confirmed through cross-section observation and analysis by performing a bead on plate (BOP) test by changing laser power and welding speed, which are the main parameters of laser welding. In addition, the welding performance was evaluated through mechanical property tests (yield strength, tensile strength, hardness, cryogenic impact strength) of a welding part after performing the high-manganese steel laser butt welding experiment. As a result, it was confirmed that the yield strength of a high-manganese steel laser welding part was 97.5% of that of a base metal, and its tensile strength was 93.5% of that of a base metal.

2014 ◽  
Vol 783-786 ◽  
pp. 21-26
Author(s):  
Xiao Jun Liang ◽  
Ming Jian Hua ◽  
Anthony J. DeArdo

Thermomechanical controlled processing is a very important way to control the microstructure and mechanical properties in low carbon, high strength steel. This is especially true in the case of bainite formation, where the complexity of the austenite-bainite transformation makes the control of the processing important. In this study, a low carbon, high manganese steel containing niobium was investigated to better understand the roles of austenite conditioning and cooling rates on the bainitic phase transformation. Specimens were compared with and without deformation, and followed by seven different cooling rates ranging between 0.5°C/s and 40°C/s. The CCT curves showed that the transformation behaviors and temperatures are very different. The different bainitic microstructures which varied with austenite deformation and cooling rates will be discussed.


2019 ◽  
Vol 79 ◽  
pp. 01001
Author(s):  
Wenwei Zhuang ◽  
Haixu Zhi ◽  
Handai Liu ◽  
Daxiang Zhang ◽  
Dongmin Shi

The test used casting process to alloy the traditional high manganese steel with adding Ti. The surface morphology of the high manganese steel sample was observed by the scanning electron microscopy.At the same time, the hardness, the tensile strength and the wear resistance of the sample were tested. Compared with the high manganese steel without alloying, it studied the micro-structure and properties of modified high manganese steel . The results show that the grain of high manganese steel alloyed by titanium alloy is refined, the inclusions is dispersed and their size is reduced. The hardness of high manganese steel is increased by 87 %~263 %, but the tensile strength is reduced. Compared with the sample without added titanium element, the wear resistance of the alloyed high manganese steel is significantly improved.


Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1185
Author(s):  
Zhimin Wang ◽  
Lulu Sun ◽  
Wenchao Ke ◽  
Zhi Zeng ◽  
Wei Yao ◽  
...  

The joining of high-temperature titanium alloy is attracting much attention in aerospace applications. However, the defects are easily formed during laser welding of titanium alloys, which weakens the joint mechanical properties. In this work, laser oscillating welding was applied to join TC31 high-temperature titanium alloy. The weld appearance, microstructure and mechanical properties of the laser welds were investigated. The results show that sound joints were formed by using laser oscillating welding method, and a large amount of martensite was presented in the welds. High mechanical properties were achieved, which was approaching to (or even equaled) the strength of the base material. The joints exhibited a tensile strength of up to 1200 ± 10 MPa at room temperature and 638 ± 6 MPa at 923 K. Laser oscillating welding is beneficial to the repression of porosity for welding high-temperature titanium alloy.


2021 ◽  
pp. 130596
Author(s):  
Xiaoyu Fan ◽  
Yuntao Li ◽  
Yanchang Qi ◽  
Chengyong Ma ◽  
Zhihua Wang ◽  
...  

1985 ◽  
Vol 27 (3) ◽  
pp. 210-212
Author(s):  
V. P. Ponomarenko ◽  
A. Ya. Shvartser ◽  
G. V. Stroganova

2021 ◽  
Vol 1035 ◽  
pp. 752-758
Author(s):  
Li Bo Guo ◽  
Jun Chao He ◽  
Guo Ping Li ◽  
Lian Wu Yan

TiC-high manganese steel-bonded carbide was prepared by powder metallurgy method with varied Mo2C content (0, 2.5%, 5%, 7.5% and 10% respectively), and the effects of Mo2C addition on the microstructure and mechanical properties of the fabricated cermets were studied. The microstructures of the fabricated cermets were observed and analyzed by scanning electron microscope (SEM), and the physical and mechanical properties of the cermets were also tested. The results show that the microstructure of the cermet without Mo2C additive was finer than that of the cermets with 2.5% and 5% Mo2C addition, though Mo2C was an effective grain growth inhibitor of TiC- and/or TiCN-based refractory materials because of low inherent solubility of TiC in Fe binder. An interesting phenomenon was also found that black core-gray rim was observed in the microstructure of the cermet without Mo2C addition. The microstructure of the fabricated cermets was fine with the increase of Mo2C content. The results also show that the relative density and hardness of the cermet increased monotonously with the increase of Mo2C content, hence, the transverse rupture strength (TRS) and impact toughness (IM) of the fabricated cermets increased first and then decreased, and the TRS and IM reached the maximum valve of 2189 MPa and 11.7 J/cm2 when Mo2C content was 7.5% and 5% respectively.


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