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.

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.

Factors Influencing Dephosphorization of Low Carbon Steel in Converter

2021 ◽  
Vol 1047 ◽  
pp. 111-119
Author(s):  
Zhao Liu ◽  
Shu Sen Cheng ◽  
Liang Wang
Keyword(s):  
Carbon Steel ◽  
Low Temperature ◽  
Slag Composition ◽  
Phosphorus Content ◽  
Low Carbon Steel ◽  
Smelting Process ◽  
Low Carbon ◽  
Factors Influencing ◽  
High Basicity ◽  
Metal Yield

A 300-metric ton converter in a steel plant in China was studied. The influence of factors such as slag composition and temperature in the smelting process on the dephosphorization effect was statistically analyzed. The dephosphorization ability of slag increased firstly and then decreased with the increase of temperature, basicity and FeO content. Low-temperature, high-basicity and high-oxidizing slag are thermodynamically beneficial to promote the dephosphorization reaction, but the basicity is higher than 4.0, and the temperature is higher than 1640 °C are not conducive to the slag to obtain better fluidity. At the same time, too high FeO content will increase the activity coefficient of P2O5, thereby increasing its activity, which is not conducive to the progress of the dephosphorization reaction. As the end point content of carbon decreases, the oxygen content increases and the phosphorus content decreases. A very low carbon content is not conducive to metal yield and temperature control.

scholarly journals Evaluation of induced residual stresses on AISI 1020 low carbon steel plate from experimental and FEM approach during TIG welding process

2019 ◽  
Vol 13 (1) ◽  
pp. 4415-4433
Author(s):  
I. B. Owunna ◽  
A. E. Ikpe
Keyword(s):  
Carbon Steel ◽  
Residual Stresses ◽  
Steel Plate ◽  
Low Carbon Steel ◽  
Welding Process ◽  
Service Condition ◽  
Tig Welding ◽  
Von Mises Stress ◽  
Low Carbon ◽  
Temperature Range

Induced residual stresses on AISI 1020 low carbon steel plate during Tungsten Inert Gas (TIG) welding process was evaluated in this study using experimental and Finite Element Method (FEM). The temperature range measured from the welding experimentation was 251°C-423°C, while the temperature range measured from the FEM was 230°C-563°C; whereas, the residual stress range measured from the welding experimentation was 144MPa-402Mpa, while the residual range measured from the FEM was 233-477MPa respectively. Comparing the temperature and stress results obtained from both methods, it was observed that the range of temperature and residual stresses measured were not exactly the same due to the principles at which both methods operate but disparities between the methods were not outrageous. However, these values can be fed back to optimization tools to obtain optimal parameters for best practices.  Results of the induced stress distribution was created from a static study where the thermal results were used as loading conditions and it was observed that the temperature increased as the von-Mises stress increased, indicating that induced stresses in welded component may hamper the longevity of such component in service condition. Hence, post-weld heat treatment is imperative in order to stress relieve metals after welding operation and improve their service life.

The Initial Life and Short Crack Propagation Life for Low Carbon Steel Based on Dislocation Method

2018 ◽  
Vol 1145 ◽  
pp. 1-7
Author(s):  
Yuan Long Yang ◽  
Qing Chun Meng ◽  
Wei Ping Hu
Keyword(s):  
Fatigue Life ◽  
Carbon Steel ◽  
Crack Propagation ◽  
Low Carbon Steel ◽  
Short Crack ◽  
Low Carbon ◽  
Grain Sizes ◽  
Steel Material ◽  
The Relationship ◽  
Good Agreement

In the paper, the relationship between the grain size and fatigue life are studied. To specify the initial and short crack propagation life of low carbon steel material, three methods are used in the simulation. At first, the K. Tanaka’s model is introduced to calculate the fatigue life of a grain. Then, the Voronoi Diagram is used to generate the microstructure of grains. At last, a criteria to specify the short crack is proposed. Based on these methods, the numerical simulation is conducted. With the help of the process, the grain sizes are generated randomly in order to specify how grain sizes effect fatigue life. The computational results are in good agreement with the experimental data. The results show that the randomness of fatigue life is closely related to the randomness of grain sizes.

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