scholarly journals Effects of metallurgical factors on reticular crack formations in Nb-bearing pipeline steel

2020 ◽  
Vol 39 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Hangyu Zhu ◽  
Lanqing Wang ◽  
Jianli Li ◽  
Jixuan Zhao ◽  
Yue Yu
Keyword(s):  
Iron Oxide ◽  
Continuous Casting ◽  
Pipeline Steel ◽  
Solidification Process ◽  
Casting Process ◽  
Chemical Compositions ◽  
Steel Matrix ◽  
Continuous Casting Process ◽  
Residual Elements ◽  
Crack Susceptibility

AbstractMicroscopic morphologies of reticular cracks in Nb-bearing pipeline surfaces are shown in this work. A decarburization layer, oxidized round spots, and the distributions of residual elements are each detected to better understand the mechanisms of reticular crack formations. The results show that reticular cracks are discontinuously distributed and filled with iron oxide. The oxidized round spots near the crack sides are larger and more intensive than steel matrix, with primary chemical compositions of Fe, Mn, and Si oxides. There is no obvious enrichment of Cu, Cr, or Sn near the crack zones. The formation of reticular cracks occurs prior to both decarburization and the formation of oxidized round spots. The ferrite potential (FP) of the examined pipeline steel is 1.05, which leads to a higher relative crack susceptibility. It is concluded that reticular cracks are generated during the continuous casting solidification process due to the extension of intergranular microcracks along grain boundaries under the abnormal conditions of the continuous casting process.

scholarly journals A model of water-spray cooling effect on a continuous casting process

2018 ◽  
Vol 240 ◽  
pp. 05022 ◽  
Author(s):  
Hocine Mzad ◽  
Abdessalam Otmani ◽  
Kamel Bey ◽  
Stanisław Łopata
Keyword(s):  
Continuous Casting ◽  
Latent Heat ◽  
Heat Dissipation ◽  
Great Influence ◽  
Solidification Process ◽  
Casting Process ◽  
Spray Cooling ◽  
Water Spray ◽  
Continuous Casting Process ◽  
Water Spray Cooling

The intention of this study is to give an idea about the influence of water-spray cooling on the solidification process of the liquid metal which enables to locate the shear region. The effect of spray heat transfer coefficient (hspray) during the liquid-to-solid transition through the cooled zone temperature and the metal latent heat of solidification are highlighted. A gray iron continuous casting process subjected to water-sprays cooling was simulated using the commercial code COMSOL MULTIPHYSICS 5.2. The obtained results show the great influence of hspray on the location of transition region as well as the relationship between hspray, wall outer temperature, latent heat dissipation, and the solidification time.

The Multi Physical Fields Modeling for 7B50 Aluminum Alloy Semi-Continuous Casting Process

2008 ◽  
Vol 575-578 ◽  
pp. 1422-1432
Author(s):  
Shi Cheng Hu ◽  
Wei Ce Ma ◽  
Xiao Qian Li ◽  
Jue Zhong
Keyword(s):  
Aluminum Alloy ◽  
Continuous Casting ◽  
Solid Phase ◽  
Thermal Contact ◽  
Convective Heat Transfer Coefficient ◽  
Three Dimensional ◽  
Solidification Process ◽  
Casting Process ◽  
Thermal Contact Conductance ◽  
Continuous Casting Process

In order to understand the solidification behavior in the semi-continuous casting process of 7B50 aluminum alloy, a thermo-mechanical model for the analysis of 7B50 aluminum alloy solidification process is presented, this model considering liquid-solid phase-change effects for the solidification alloy. The thermal contact conductance between the mould wall and the ingot, the convective heat transfer coefficient are taken into account in the model. The distribution of temperature and stress in the process of semi-continuous casting of 7B50aluminum alloy are analyzed in three-dimensional finite element methods based on the above models. The variation of casting speed to influence the temperature and stress of the ingot in the process of semi-continuous casting is studied.

scholarly journals High Temperature Rheometric Measurements of Mould Powders

2015 ◽  
Vol 60 (1) ◽  
pp. 289-294 ◽  
Author(s):  
W. Ślęzak ◽  
M. Korolczuk-Hejnak ◽  
P. Migas
Keyword(s):  
High Temperature ◽  
Continuous Casting ◽  
Carbon Content ◽  
Casting Process ◽  
Chemical Compositions ◽  
Continuous Casting Process ◽  
Shear Rates ◽  
Rheological Measurements ◽  
Real Process ◽  
Theoretical Considerations

Abstract Issues of viscosity and rheological properties of powder moulds are important from the perspective of modelling, along with the control of continuous casting process. Conducted analysis within subject literature indicates that there are many theoretical considerations concerning the effects of viscosity of powder moulds. The objective of this study was to perform rheological measurements of powder moulds, the study contains the results of rheological tests of seven chemical compositions with a carbon content from 5.0 to 10.7% and which were tested with applied shear rates from 10 to 40 s-1, which are similar to those in a real process: the velocity of strand passes/drawing and mould movements.

The Air Reoxidation and the Formation of Large Inclusions in Continuous Casting Process

1973 ◽  
Vol 59 (1) ◽  
pp. 72-84 ◽  
Author(s):  
Kichinosuke MATSUNAGA ◽  
Chikakazu NAMIKI ◽  
Taiji ARAKI
Keyword(s):  
Continuous Casting ◽  
Casting Process ◽  
Continuous Casting Process

Development of Electromagnetic Swirling Flow in Immersion Nozzle in Continuous Casting Process of Steel

2011 ◽  
Vol 295-297 ◽  
pp. 1284-1288 ◽  
Author(s):  
De Wei Li ◽  
Zhi Jian Su ◽  
Li Wei Sun ◽  
Katsukiyo Marukawa ◽  
Ji Cheng He
Keyword(s):  
Continuous Casting ◽  
Swirling Flow ◽  
Casting Process ◽  
Continuous Casting Process ◽  
New Process ◽  
Electromagnetic Generator ◽  
Set Up ◽  
The Magnetic Field ◽  
Immersion Nozzle

Swirling flow in an immersion nozzle is effective on improving quality of casting block and casting speed in continuous casting process of steel. However, a refractory swirl blade installed in the nozzle is liable to cause clogging, which limit the application of the process. In this study a new process is proposed, that is a rotating electromagnetic field is set up around an immersion nozzle to induce a swirling flow in it by Lorentz force. New types of swirling flow electromagnetic generator are proposed and the effects of the structure of the generator, the coil current intensity and frequency on the magnetic field and on the flow field in the immersion nozzle are numerically analyzed.

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