scholarly journals Modelling the Austenite to Ferrite Phase Transformation in Low Carbon Steels in Terms of the Interface Mobility.

2000 ◽  
Vol 40 (7) ◽  
pp. 713-718 ◽  
Author(s):  
T. A. Kop ◽  
Y. van Leeuwen ◽  
Jilt Sietsma ◽  
S. van der Zwaag
Keyword(s):  
Phase Transformation ◽  
Carbon Steels ◽  
Ferrite Phase ◽  
Low Carbon ◽  
Low Carbon Steels ◽  
Interface Mobility

scholarly journals Optimization of Niobium Content in Direct Quenched High-Strength Steels

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 807
Author(s):  
Jaakko Hannula ◽  
David Porter ◽  
Antti Kaijalainen ◽  
Mahesh Somani ◽  
Jukka Kömi
Keyword(s):  
Phase Transformation ◽  
High Strength Steels ◽  
Significant Loss ◽  
Carbon Steels ◽  
Optimum Level ◽  
Low Carbon ◽  
Niobium Content ◽  
Low Carbon Steels ◽  
Finish Rolling ◽  
Different Levels

This paper focuses on understanding the effect of niobium content on the phase transformation behavior and resultant mechanical properties of thermomechanically rolled and direct-quenched low carbon steels containing 0.08 wt.% carbon. Investigated steels contained three different levels of niobium: 0, 0.02 and 0.05 wt.%. The continuous cooling transformation (CCT) diagrams covering cooling rates in the range 3–96 °C/s constructed based on the dilatometer studies showed only a minor effects of Nb on the phase transformation characteristics. In addition, experiments were performed for reheating and soaking the slabs at 1050–1200 °C and the results revealed that for these low-carbon steels, Nb failed to prevent the austenite grain growth during slab reheating. In the case of hot rolling trials, two different finish rolling temperatures of 820 °C and 920 °C were used to obtain different levels of pancaking in the austenite prior to direct quenching. The resultant microstructures were essentially mixtures of autotempered martensite and lower bainite imparting yield strengths in the range 940–1070 MPa. The lower finish rolling temperature enabled better combinations of strength and toughness in all the cases, predominantly due to a higher degree of pancaking in the austenite. The optimum level of Nb in the steel was ascertained to be 0.02 wt.%, which resulted not only in marginally higher strength but also without any significant loss of impact toughness.

EBSD Investigation of Phase Transformation in Low Carbon Steels

2008 ◽  
pp. 243-250
Author(s):  
Sophie Lubin ◽  
Anne-Françoise Gourgues-lorenzon ◽  
Hélène Regle ◽  
Frank Montheillet ◽  
Brigitte Bacroix
Keyword(s):  
Phase Transformation ◽  
Carbon Steels ◽  
Low Carbon ◽  
Low Carbon Steels

Phase transformations in low-carbon steels ; modelling the kinetics in terms of the interface mobility

1999 ◽  
Vol 09 (PR9) ◽  
pp. Pr9-401-Pr9-409 ◽  
Author(s):  
Y. van Leeuwen ◽  
T. A. Kop ◽  
J. Sietsma ◽  
S. van der Zwaag
Keyword(s):  
Phase Transformations ◽  
Carbon Steels ◽  
Low Carbon ◽  
Low Carbon Steels ◽  
Interface Mobility

Surface Microstructure and Texture Evolution during Interrupted Annealing in Ultra Low Carbon Steels

2010 ◽  
Vol 89-91 ◽  
pp. 202-207
Author(s):  
J. Gautam ◽  
Roumen H. Petrov ◽  
Leo Kestens ◽  
Elke Leunis
Keyword(s):  
Phase Transformation ◽  
Surface Texture ◽  
Texture Evolution ◽  
Low Carbon Steel ◽  
Carbon Steels ◽  
Control Surface ◽  
Surface Microstructure ◽  
Low Carbon ◽  
Metal Vapour ◽  
Low Carbon Steels

The austenite-to-ferrite phase transformation, which is an inherent feature of low-alloyed ultra low carbon steels, has scarcely been investigated to control surface texture and microstructure evolution. This paper investigates the systematic evolution of texture and microstructure at the metal-vapour interface during interrupted annealing in vacuum. Interrupted annealing experiments were carried out on three ultra low carbon steel sheets alloyed with Mn, Al and Si. The texture and microstructures have been investigated by X-ray diffraction and SEM-EBSD techniques. These results reveal a very clear variation in the surface texture components as well as in the surface microstructure after BCC recrystallisation and double  transformation interrupted annealing. The recrystallisation texture consists mainly of a <111>//ND fibre, while the transformation texture at the surface exhibits a <100>// ND fibre in combination with components of the <110> //ND fibre. It has been revealed that the latter specific surface texture was present in a monolayer of outer surface grains which were in direct contact with the vapour atmosphere. This observed phenomenon could be explained by considering the role of surface energy anisotropy occurring during phase transformation annealing.

MITTAL DI-FORM 140T, HB T965

Alloy Digest ◽  
2007 ◽  
Vol 56 (4) ◽  
Keyword(s):  
Tensile Strength ◽  
Yield Strength ◽  
Martensite Phase ◽  
Carbon Steels ◽  
Ferrite Phase ◽  
Dual Phase ◽  
Low Carbon ◽  
Dp Steel ◽  
Low Carbon Steels ◽  
Soft Ferrite

Abstract MITTAL DI-FORM 140T and HB T965 are low carbon steels with dual phase manganese and silicon composition. Dual-phase (DP) steel microstructures typically consist of a soft ferrite phase with dispersed islands of a hard martensite phase. The martensite phase is substantially stronger than the ferrite phase. The dual-phase grades, including those with high tensile strengths of 965 MPa (140 ksi), that are designed for forming (DI-FORM), also have low yield-strength-to-tensile-strength ratios to improve formability. This datasheet provides information on microstructure and tensile properties as well as deformation and fatigue. It also includes information on forming and surface treatment. Filing Code: SA-566. Producer or source: Mittal Steel USA Flat Products.

Simulation of Phase Transformation by Analysis of First Derivative of Dilatation Using Avrami Equation during Continuous Cooling in Low Carbon Steels

2011 ◽  
Vol 409 ◽  
pp. 407-410
Author(s):  
Bong June Park ◽  
Jong Min Choi ◽  
Kyung Jong Lee
Keyword(s):  
Phase Transformation ◽  
Inflection Point ◽  
Carbon Steels ◽  
Avrami Equation ◽  
Temperature Phase ◽  
Low Carbon ◽  
Low Carbon Steels ◽  
Continuous Cooling ◽  
First Derivative ◽  
Low Temperature Phase

The phase transformation during continuous cooling in low carbon steel has been widely measured by dilatometer using the lever rule. However, the concept of lever rule has several limitations. In low carbon steels, it is observed that overlapped transformation region of multi-phase and inflection point of small amount of low temperature phase is hardly differentiated. First derivatives of LVDT during continuous cooling could be better way to identify the inflection point and transformation region of phases (especially low temperature phase). Furthermore, first derivative of LVDT could be expressed as the lattice parameter and phase fraction due to temperature. Therefore, phase transformation behavior is simulated by the analysis of first derivative of LVDT using Avrami equation from experimental LVDT. As a result, the start, finish temperature and the amount of each phase are determined. The method is also confirmed by OM and SEM.

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