Quantitative Examination of Segregation in Slabs for the Production of Sour Service Linepipe

1996 ◽  
Author(s):  
Bernhard Hoh
Keyword(s):  
Statistical Evaluation ◽  
Solidification Process ◽  
Constitutive Relationship ◽  
Computer Assisted ◽  
Characteristic Parameters ◽  
Large Area ◽  
Steel Mills ◽  
Continuously Cast ◽  
Quantitative Examination ◽  
Sour Service

Segregation is a major problem to be overcome by producers of HIC resistant steels. Primary segregation is an inherent and unavoidable feature of the solidification process. The constitutive relationship between solid and liquid stage determines microsegregation and it is influenced by the chemical composition of the steel and its cooling rate. Macrosegregation occurs when microsegregated liquids collect and shift through liquid flow. OREGON STEEL MILLS has conducted systematic measurements on pressure-cast slabs using a computer assisted micro analyzer. This microprobe measures element concentrations over a large area of the specimen. A statistical evaluation based on the frequency distribution of the concentrations forms the basis of a quantitative analysis. From this, characteristic parameters such as the segregation factor and maximum concentration can be derived. This paper discussed the influence of carbon on segregation structure and on segregation properties of manganese, and compares the results with those of continuously cast slabs.

Influence of Casting Speed on Solidification Process and Solidification Structure of Continuously Cast Bloom

2011 ◽  
Vol 402 ◽  
pp. 123-131 ◽  
Author(s):  
Zi Bing Hou ◽  
Guo Guang Cheng
Keyword(s):  
Surface Temperature ◽  
Casting Speed ◽  
Control Method ◽  
Target Surface ◽  
Solidification Process ◽  
Solidification Structure ◽  
Transfer Model ◽  
Proportional Control ◽  
Temperature Method ◽  
Continuously Cast

On the basis of problems about quality of steel products that a certain special steel factory facing, a heat transfer model about continuous casting process was first established, then the influence of casting speed on solidification process and solidification structure of continuously cast bloom was comprehensively studied. It is shown that shell thickness leaving mold, crater length and the value of H(which is chosen as the measurement criterion of the number of the heterogeneous nucleation nucleus) are influenced most with increasing casting speed. Meantime, compared with proportional control method, solidification process of continuously cast bloom is in uniform variation with small fluctuation by target surface temperature method. What’s more, when centre solidification time is considered only, central zone macrosegregation may form more easily at last by proportional control method with increasing casting speed, but it is opposite by target surface temperature method; when the value of G/V1/2 and the value of H are considered only, the ratio of equiaxed grain will increase with increasing casting speed by proportional control method, but it is opposite by target surface temperature method.

The Effect of Al-17wt.%Si Alloy Melt Overheating on Solidification Process and Microstructure Evolution

2011 ◽  
Vol 176 ◽  
pp. 29-34 ◽  
Author(s):  
Jaroslaw Piątkowski
Keyword(s):  
Microstructure Evolution ◽  
Solidification Process ◽  
Primary Silicon ◽  
Characteristic Parameters ◽  
Probe Characteristic ◽  
Alloy Solidification ◽  
Silicon Crystals

The effect of overheating on the solidification process and microstructure evolution in AlSi17 silumin was discussed. The alloy melt was held for 40 minutes at 780, 860, 940 and 1020oC, and then cast at a temperature of 780oC to standard ceramic probe. Characteristic parameters of the AlSi17 alloy solidification process, especially Tliq, TE, Tsol, were determined. Examinations of microstructure were also carried out, showing that the higher was the overheating temperature, the higher was the degree of the primary silicon crystals refinement.

Influence of Secondary Cooling Mode on Solidification Structure and Macro-segregation Behavior for High-carbon Continuous Casting Bloom

2017 ◽  
Vol 36 (7) ◽  
pp. 741-753 ◽  
Author(s):  
Kun Dou ◽  
Zhenguo Yang ◽  
Qing Liu ◽  
Yunhua Huang ◽  
Hongbiao Dong
Keyword(s):  
Continuous Casting ◽  
Casting Process ◽  
Coupling Model ◽  
Solidification Structure ◽  
Secondary Cooling ◽  
Characteristic Parameters ◽  
High Carbon ◽  
Cooling Mode ◽  
Gcr15 Steel ◽  
Continuously Cast

AbstractA cellular automaton–finite element coupling model for high-carbon continuously cast bloom of GCr15 steel is established to simulate the solidification structure and to investigate the influence of different secondary cooling modes on characteristic parameters such as equiaxed crystal ratio, grain size and secondary dendrite arm spacing, in which the effect of phase transformation and electromagnetic stirring is taken into consideration. On this basis, evolution of carbon macro-segregation for GCr15 steel bloom is researched correspondingly via industrial tests. Based on above analysis, the relationship among secondary cooling modes, characteristic parameters for solidification structure as well as carbon macro-segregation is illustrated to obtain optimum secondary cooling strategy and alleviate carbon macro-segregation degree for GCr15 steel bloom in continuous casting process. The evaluating method for element macro-segregation is applicable in various steel types.

scholarly journals Kinetic Analysis of the Transformation from 14M Martensite to L21 Austenite in Ni-Fe-Ga Melt Spun Ribbons

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 849
Author(s):  
Alejandro F. Manchón-Gordón ◽  
Raúl López-Martín ◽  
Jhon J. Ipus ◽  
Javier S. Blázquez ◽  
Peter Svec ◽  
...  
Keyword(s):  
Melt Spinning ◽  
Room Temperature ◽  
Solidification Process ◽  
Austenite Phase ◽  
Isothermal Kinetics ◽  
Martensitic Transition ◽  
Characteristic Parameters ◽  
First Order ◽  
Kinetics Of ◽  
Good Agreement

In this study, the non-isothermal kinetics of the martensitic transition from 14M modulated martensite to austenite phase in Ni55Fe19Ga26 ribbons obtained by melt-spinning has been analyzed. The proximity of the martensitic transition to room temperature makes it very sensitive to pressure and subtle differences for different pieces of the ribbon (ascribed to stresses stored in the ribbon during its rapid solidification process). Despite the dispersion in the characteristic parameters of the transition, a general behavior is observed with a decreasing activation energy as the heating rate increases due to the nucleation driven character of the transition. It has been shown that a first-order autocatalysis can describe the temperature evolution of the austenite fraction using only two experimental temperatures. Predicted curves are in good agreement with experimental data.

Model Study about the Influence of Superheat on Macrosegregation Formation in Continuously Cast Bloom of Special Steel

2011 ◽  
Vol 295-297 ◽  
pp. 1088-1094 ◽  
Author(s):  
Zi Bing Hou ◽  
Guo Guang Cheng
Keyword(s):  
Shell Thickness ◽  
Continuous Caster ◽  
Solidification Process ◽  
Transfer Model ◽  
Equiaxed Crystal ◽  
Steel Mill ◽  
Special Steel ◽  
Model Study ◽  
Continuously Cast ◽  
Process Heat

Aiming at the facing problems of the actual continuous caster in a certain steel mill, a solidification-process heat transfer model about continuously cast bloom of special steel was first established, then the influence of superheat on macrosegregation formation was studied. It is shown that the crater length will become longer, the shell thickness will become thinner with increasing the superheat. Meanwhile, when decreasing the superheat , the value of will decrease and the value of H will obviously increase, then the equiaxed crystal ratio will be raised greatly. However, the bloom centre solidification time will increase. Consequently, attention should be paid to this point when decreasing the superheat in order to lessen the extent of macrosegregation.

Computer-assisted area detector masking

2017 ◽  
Vol 24 (2) ◽  
pp. 506-508 ◽  
Author(s):  
Christopher J. Wright ◽  
Xiao-Dong Zhou
Keyword(s):  
Statistical Significance ◽  
Computer Assisted ◽  
X Ray Diffraction ◽  
Large Area ◽  
One Dimensional ◽  
X Ray ◽  
Area Detector ◽  
Rapid Acquisition ◽  
Predominant Type ◽  
Angle Scattering

Area detectors have become the predominant type of detector for the rapid acquisition of X-ray diffraction, small-angle scattering and total scattering. These detectors record the scattering for a large area, giving each shot good statistical significance to the resulting scattered intensity I(Q) pattern. However, many of these detectors have pixel level defects, which cause error in the resulting one-dimensional patterns. In this work, new software to automatically find and mask these dead pixels and other defects is presented. This algorithm is benchmarked with both ideal simulated and experimental datasets.

Efficient segmentation of large-area skin images: a statistical evaluation

1997 ◽  
Vol 3 (1) ◽  
pp. 28-35 ◽  
Author(s):  
D. P. Filiberti ◽  
J. A. Gaines ◽  
P. Bellutta ◽  
P. Ngan ◽  
D. A. Perednia
Keyword(s):  
Statistical Evaluation ◽  
Large Area

scholarly journals VIRTUAL RESTORATION OF MISSING PAINT LOSS OF MURAL BASED ON GENERATIVE ADVERSARIAL NETWORK

2021 ◽  
Vol XLVI-M-1-2021 ◽  
pp. 807-811
Author(s):  
Q. Wang ◽  
M. Hou ◽  
S. Lyu
Keyword(s):  
Cultural Heritage ◽  
Network Model ◽  
Feature Matching ◽  
Absolute Error ◽  
Computer Assisted ◽  
Large Area ◽  
Generative Adversarial Network ◽  
Adversarial Network ◽  
Secondary Damage ◽  
Digital Protection

Abstract. Mural painting is one of the important cultural heritage reflecting the historical migration of the nation. In order to inherit these precious historical and cultural heritage, how to non - destructively and digitally protect and restore the existing murals has become an urgent task. The use of computer - assisted restoration of murals can not only save manpower and material resources, but also avoid secondary damage to the murals.However, most of the existing computer-assisted mural restoration algorithms use similar blocks with priority calculations and matching blocks in adjacent areas to guide mural restoration. There are some problems such as incoherent overall semantic structure, unnatural detail texture and inability to effectively repair large area missing remain to be solved. Aiming at the problems existing in the restoration of large area diseases such as paint loss and color fading in murals, we constructed a fine image restoration network model which based on generative adversarial network. A multi-scale dense matching repair network based on a generative adversarial network is constructed. First, the dense combination of dilated convolutions is used to improve the repair effect of detailed textures, Then, mean absolute Error, (Visual Geometry Group, VGG) feature matching, auto-guided regression, and geometric alignment are used as the loss function to guide the training of the generative network. Second, the discriminator with local and global branches is used to train the discriminant network, so that the repaired image is in the local and global content. Experiments were performed on the three mural data sets one by one. The results show that the network model can effectively restore the lines and faces in the murals. The images restored are not only coherent in semantic details, but also natural in color, which is conducive to the appreciation and display of murals. Thus, as one of the important directions of cultural heritage digital protection，the use of generative adversarial network in the digital restoration of ancient murals have been proved to be effective. It not only provides a reference for the true restoration of the murals but also means a lot to the preservation of murals.

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