scholarly journals Experimental Study on Laser-MIG Hybrid Welding of Thick High-Mn Steel Plate for Cryogenic Tank Production

2021 ◽  
Vol 9 (6) ◽  
pp. 604
Author(s):  
Du-Song Kim ◽  
Hee-Keun Lee ◽  
Woo-Jae Seong ◽  
Kwang-Hyeon Lee ◽  
Hee-Seon Bang
Keyword(s):  
Low Temperature ◽  
Yield Strength ◽  
Steel Plate ◽  
Weld Zone ◽  
Base Material ◽  
Hardness Test ◽  
Steel Plates ◽  
Hybrid Welding ◽  
Temperature Impact ◽  
Mn Steel

The International Maritime Organization has recently updated the ship emission standards to reduce atmospheric contamination. One technique for reducing emissions involves using liquefied natural gas (LNG). The tanks used for the transport and storage of LNG must have very low thermal expansion and high cryogenic toughness. For excellent cryogenic properties, high-Mn steel with a complete austenitic structure is used to design these tanks. We aim to determine the optimum welding conditions for performing Laser-MIG (Metal Inert Gas) hybrid welding through the MIG leading and laser following processes. A welding speed of 100 cm/min was used for welding a 15 mm thick high-Mn steel plate. The welding performance was evaluated through mechanical property tests (tensile and yield strength, low-temperature impact, hardness) of the welded joints after performing the experiment. As a result, it was confirmed that the tensile strength was slightly less than 818.4 MPa, and the yield strength was 30% higher than base material. The low-temperature impact values were equal to or greater than 58 J at all locations in the weld zone. The hardness test confirmed that the hardness did not exceed 292 HV. The results of this study indicate that it is possible to use laser-MIG hybrid welding on thick high-Mn steel plates.

Development of High-Strength Steel Plates for Low-Temperature Use

1988 ◽  
Vol 110 (3) ◽  
pp. 171-176
Author(s):  
Y. Nakano ◽  
Y. Saito ◽  
K. Amano ◽  
M. Koda ◽  
Y. Sannomiya ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Yield Strength ◽  
Structural Steel ◽  
Welded Joints ◽  
High Strength Steel ◽  
Control Process ◽  
Charpy Impact ◽  
High Strength ◽  
Steel Plates

This paper describes the metallurgical approaches for producing 415MPa and 460MPa yield strength offshore structural steel plates and the mechanical properties of the steel plates and their welded joints. A thermo-mechanical control process (TMCP) was adopted to manufacture YP415MPa and YP460MPa steel plates with weldability comparable to conventional YP355MPa steel plates. The Charpy impact and CTOD tests of the steel plates and their welded joints proved to be very good.

Development of 550 MPa Yield Strength Steel Plate for Offshore Structures

2004 ◽  
Author(s):  
Takahiro Kamo ◽  
Takeshi Urabe ◽  
Kazushi Ohnishi ◽  
Hirofumi Nakamura ◽  
Shuji Okaguchi ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Yield Strength ◽  
Base Metal ◽  
Steel Plate ◽  
High Strength ◽  
Offshore Structures ◽  
Steel Plates ◽  
Offshore Structure ◽  
Copper Precipitation ◽  
High Toughness

Offshore structure steel with high strength of YS550MPa has been investigated. As for offshore structure steel, high toughness in welded joints is required in addition to that in base metal. TMCP type steel of up to YS420MPa grade is used widely, and up to YS500MPa grade is reported in some papers. However, steel of higher strength grade with good toughness and weldability will be beneficial to structures in strict conditions. To reach the YS550MPa requirement, hardening effect by Cu precipitation was utilized. Steel plates were designed with micro-alloyed low C-Mn-Cu-Ni-Cr-Mo system. The combination of the copper precipitation and TMCP technology can increase strength without deteriorating toughness and weldability. Heat treatment for Cu precipitation was carried out to optimize the balance of strength and toughness of the base metal. The developed steel also shows good HAZ CTOD toughness up to 76.2mm thickness in several welding conditions including after PWHT. The newly developed steel has the possibility to increase the flexibility to design large-sized structures.

scholarly journals Effect of Microstructure on Low-Temperature Fracture Toughness of a Submerged-Arc-Welded Low-Carbon and Low-Alloy Steel Plate

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1839
Author(s):  
Byeong Chan Choi ◽  
Byoungkoo Kim ◽  
Byung Jun Kim ◽  
Yong-Wook Choi ◽  
Sang Joon Lee ◽  
...  
Keyword(s):  
Low Temperature ◽  
Fracture Behavior ◽  
Steel Plate ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Temperature Fracture ◽  
Temperature Impact ◽  
Ebsd Technique ◽  
The Relationship ◽  
Submerged Arc

This study investigated the low-temperature fracture behavior of an 80-mm-thick low-carbon steel plate welded by submerged arc. The relationship between impact absorbed energy and ductility–brittle transition temperature (DBTT) based on the microstructures was evaluated through quantitative analysis on grain size and complex constituent phases using advanced EBSD technique. The microstructure formed differently depending on the heat affections, which determined fracture properties in a low-temperature environment. Among the various microstructures of the heat-affected zone (HAZ), acicular ferrite has the greatest resistance to low-temperature impact due to its fine interlocking formation and its high-angle grain boundaries.

Enhancing the Toughness of Heavy Thick X80 Pipeline Steel Plates by Microstructure Control

2011 ◽  
Vol 194-196 ◽  
pp. 1183-1191 ◽  
Author(s):  
Wen Jin Nie ◽  
Wei Feng Xin ◽  
Tian Ming Xu ◽  
Pei Jian Shi ◽  
Xiao Bing Zhang
Keyword(s):  
Grain Size ◽  
Low Temperature ◽  
Pipeline Steel ◽  
Base Material ◽  
Steel Plates ◽  
Microstructure Control ◽  
X80 Pipeline Steel ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
X80 Steel

The experiment results show that the microstructure control plays a key role for enhancing toughness of heavy thick X80 plates at low temperature, especially DWTT property. The toughness of heavy thick X80 plate at low temperature is not only related to the bainite grains and M/A islands, but also impacted by the original austenite grain size. Finer original austenite grain size benefits to increase the BF/AF ratio in volume of a base material enlarge the crystal orientation difference of microstructure transformation inside austenite. Cracks on a broken section of DWTT samples can (a) penetrate the coarse grains directly, (b) propagate in Zig-Zaga way in the fine grains, and (c) be around the boundary of original austenite grains. The stable and high toughness of heavy thick X80 steel plates from the mass production can be achieved at low temperature made with the reasonable chemistry, clean steel, non-defect slab technologies and OHTP rolling practice.

scholarly journals A Study on Steel-Concrete-Steel Wall to Resist Perforation from Rigid Projectile Impact

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Pengfei Han ◽  
Jingbo Liu ◽  
Bigang Fei ◽  
Fei Wang
Keyword(s):  
Yield Strength ◽  
Nuclear Power ◽  
Power Plants ◽  
Steel Plate ◽  
Steel Plates ◽  
Dissipated Energy ◽  
Calculation Formula ◽  
Rigid Projectile ◽  
Calculation Results ◽  
Energy Dissipated

A calculation method of SCS wall which is used in the third generation of nuclear power plants to resist perforation from rigid projectile based on energy method is proposed in this paper. The energy is divided into four parts including the energy dissipated by front steel plate, concrete, back steel plate, and tie bars. The method accounts for the perforation of the concrete and steel plates separately and accounts for the interaction between them, and a practical antiperforation calculation formula of SCS wall with tie bars is given. The most formular results are close to the test results and the FEM results with a deviation less than 10%, which shows that the calculation formula given in this paper is reasonable and credible to effectively evaluate the perforation failure of the SCS wall and carry out a relevant design. The energy dissipated by the steel plate is much larger than that of the tie bars through a comparative analysis of dissipated energy. The effects of various factors on perforation velocity are analyzed according to finite element calculation results, which can be roughly divided into three categories: the influence of the thickness of steel plate and distance of tie bar is the largest effect, followed by that of yield strength of steel plate, yield strength of tie bar and diameter of tie bar, and that of compressive strength of concrete is the smallest effect.

scholarly journals FINITE ELEMENT MODELING OF STEEL PLATES UNDER MONOTONIC LOADING

2021 ◽  
Author(s):  
Bilal Nasir Shamsaldin
Keyword(s):  
Stress Distribution ◽  
Yield Strength ◽  
Steel Plate ◽  
Steel Plates ◽  
Earthquake Resistant ◽  
Earthquake Resistant Structures ◽  
Quadrilateral Meshing ◽  
Deformation Stress ◽  
Double Diamond ◽  
Precise Simulation

Steel plate fuses can be used as energy dissipating devices in earthquake-resistant structures. After an earthquake, the structure remains essentially elastic and only the deformed fuse require replacement. This report simulates the monotonic response of steel plate specimens. The effects of different inputs such as imperfection, shape and size of the fuse openings, and different meshing types on yield strength, deformation, stress distribution, and displacement are studied by using ANSYS Mechanical APDL. The study found that increasing imperfection increases displacement and decreases yield strength. It was also concluded that as the hole size in the steel plate is increased, the fuse yield strength is slightly increased to a point then is decreased. Double diamond shape showed better response in terms of displacement and stress distribution, this is because of the link shape formed by the two holes. Finer quadrilateral meshing method provide precise simulation results over longer time.

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