Characteristics of Austenite Transformation During Post Forge Cooling of Large-Size High Strength Steel Ingots

2014 ◽  
Vol 3 (4) ◽  
pp. 281-297 ◽  
Author(s):  
S. M. Chentouf ◽  
M. Jahazi ◽  
L.-P. Lapierre-Boire ◽  
S. Godin
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Austenite Transformation ◽  
Large Size ◽  
Steel Ingots

scholarly journals In situobservation of bainite to austenite transformation of microalloyed high strength steel during simulated welding cycle

2014 ◽  
Vol 19 (5) ◽  
pp. 402-407 ◽  
Author(s):  
X. W. Lei ◽  
H. H. Wang ◽  
K. M. Wu ◽  
A. A. Shirzadi ◽  
Y. Q. Yin ◽  
...  
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Austenite Transformation ◽  
Welding Cycle

scholarly journals Analysis of Void Closure during Open Die Forging Process of Large Size Steel Ingots

2016 ◽  
Vol 716 ◽  
pp. 579-585 ◽  
Author(s):  
Nathan Harris ◽  
Davood Shahriari ◽  
Mohammad Jahazi
Keyword(s):  
Strain Rate ◽  
High Strength Steel ◽  
Volumetric Strain ◽  
High Strength ◽  
Material Model ◽  
Void Closure ◽  
Forging Process ◽  
Large Size ◽  
Die Forging ◽  
Open Die Forging

Large size forged ingots, made of high strength steel, are widely used in aerospace, transport and energy applications. The presence of internal voids in the as-cast ingot may significantly affect the mechanical properties of final products. Thus, such internal defects must be eliminated during first steps of the open die forging process. In this paper, the effect of in-billet void positioning on void closure throughout the ingot breakdown process and specifically the upsetting step in a large ingot size steel is quantitatively investigated. The developed Hansel-Spittel material model for new high strength steel is used in this study. The ingot forging process (3D simulation) was simulated with Forge NxT 1.0® according to existing industrial data. A degree of closure of ten virtual existing voids was evaluated using a semi-analytical void closure model. It is found that the upsetting process is most effective for void closure in core regions and central upper billet including certain areas within the dead metal zone (DMZ). The volumetric strain rate is determined and two types of inertial effects are observed. The dependence of void closure on accumulated equivalent deformation is calculated and discussed in relation to void in-billet locations. The original combination of information from both relative void closure and the volumetric strain rate provides a way to optimize the forging process in terms of void elimination.

Macrosegregation Characteristics of Ferrite and Austenite Stabilizer Elements in Large Size High Strength Steel Ingot

2020 ◽  
Vol 846 ◽  
pp. 82-86
Author(s):  
Abdelhalim Loucif ◽  
Chun Ping Zhang ◽  
Mohammad Jahazi ◽  
Louis Philippe Lapierre-Boire
Keyword(s):  
High Strength Steel ◽  
Steel Ingot ◽  
High Strength ◽  
Alloying Elements ◽  
X Ray Diffraction ◽  
Alloying Element ◽  
Solidification Mode ◽  
Large Size ◽  
Austenite Stabilizer ◽  
Good Agreement

In the present work, the segregation degrees of ferrite and austenite stabilizer alloying elements were analyzed for a high strength steel. For this, samples were taken from the surface and center of the hot-top and the upper section of a 40 MT ingot. The results showed that the positive segregation ratios for all the investigated elements were higher in the ingot center than in the surface with higher values for austenite stabilizer elements. The increase of austenite alloying element stabilizers was accompanied by the change in the primary solidification mode of the austenite phase. The obtained results are in good agreement with the observed presence of austenite, revealed by X-ray diffraction analysis, stabilized by the austenite alloying elements.

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