Grain Refinement of a Cold Rolled TRIP Assisted Steel after Ultra Short Annealing

2012 ◽  
Vol 715-716 ◽  
pp. 661-666 ◽  
Author(s):  
Roumen H. Petrov ◽  
Jurij J. Sidor ◽  
Wlodzimierz Kaluba ◽  
Leo Kestens
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Steel Sheet ◽  
Intercritical Annealing ◽  
Austenite Formation ◽  
Rolled Steel ◽  
Structural Refinement ◽  
Cold Rolled ◽  
Short Annealing ◽  
Ferrite Grain Size

Recrystallization and austenite formation in a TRIP-assisted steel during conventional and ultra fast reheating for intercritical annealing are studied with the purpose to clarify the possibility for grain refinement. Partially recrystallized (or transformed) samples were prepared by reheating and water quenching to temperatures between 650 and 1050°C at reheating rates of 10, 50, and 3000 °C/s, respectively, without isothermal soaking from 95% cold rolled steel sheet with ferrite-pearlite microstructure. By monitoring the hardness and microstructure, it was shown that the increase of the reheating rate from 10 to 3000°C/s causes grain refinement from 5µm to 1µm in diameter and the final ferrite grain size depends significantly on both reheating temperature and reheating rate. It was observed that after an extreme reheating rate of 3000°C/s the α-γ phase transformation starts before the completion of the recrystallization. This opens up possibilities for further structural refinement and alternative texture control.

Microstructure and Properties of Ultrafast Annealed High Strength Steel

2013 ◽  
Vol 753 ◽  
pp. 554-558 ◽  
Author(s):  
Roumen H. Petrov ◽  
Farideh Hajyakbari ◽  
Fernando Ramos Saz ◽  
Jurij Sidor ◽  
Maria Jesus Santofimia ◽  
...  
Keyword(s):  
Grain Size ◽  
Phase Transformation ◽  
High Strength Steel ◽  
High Strength ◽  
Deformation Texture ◽  
Point Of View ◽  
Structural Refinement ◽  
Cold Rolled ◽  
Ferrite Grain Size ◽  
Martensite Structure

The grain size, recrystallization, phase transformation and mechanical properties of a cold-rolled high-strength steel (HSS) are studied after annealing with high (~140°C/s) and ultra-high (~1500°C/s) reheating rate, followed by subsequent water quenching without isothermal soaking. By monitoring the hardness and microstructure, it was shown that the increase of the reheating rate from 140°C/s to 1500°C/s causes grain refinement from 5 µm to 1 µm in diameter and the final ferrite grain size depends significantly on the reheating temperature and reheating rate. It was observed that after an extreme reheating rate of ~1500°C/s the α-γ phase transformation starts before the completion of recrystallization in the recovered matrix. The crystallographic texture of the ultrafast reheated and water-quenched high-strength steel inherits the cold-rolled deformation texture with well pronounced RD and ND texture fibres, even after the α-γ-α′ phase transformations. It was found that the ultrafast reheating results in a very fine non-equilibrium ferrite-martensite structure with an excellent ultimate tensile strength of ~1400 MPa and an acceptable elongation at fracture. The observed data are very promising from industrial application point of view and open up possibilities for further structural refinement and alternative texture control.

Texture Formation in High Strength Low Alloy Steel Reheated with Ultrafast Heating Rates

2011 ◽  
Vol 702-703 ◽  
pp. 798-801 ◽  
Author(s):  
Roumen H. Petrov ◽  
Jurij J. Sidor ◽  
Leo Kestens
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Electron Backscatter Diffraction ◽  
Hsla Steel ◽  
Rolling Texture ◽  
Deformation Texture ◽  
Austenite Formation ◽  
Texture Formation ◽  
Heating Rates ◽  
Ferrite Grain Size

Texture formation during annealing of a 95% cold rolled HSLA steel with 10°C/s and ~3000°C/s was studied with the purpose to investigate the interaction between the recrystallization and the austenite formation as well as the possibility of grain refinement. The recrystallization and austenite formation were monitored by means of optical microscopy (OM), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). It was found that at extreme reheating rates of 1000°C/s and higher, the α-γ phase transformation starts before the completion of recrystallization and the deformation texture is partially retained in the samples after annealing. The crystallographic texture observed in the martensitic phase which is the product of intercritical austenite transformation in as-quenched samples, i.e. after the double α-γ-α’ transformation, is the same as the initial cold rolling texture, which is an indication for the texture memory effect. After ultra fast reheating with average reheating rates of 1000°C/s and higher a significant grain refinement was observed with an average ferrite grain size of ~1µm. The obtained final ferrite grain size depends significantly on both the reheating temperature and the reheating rate.

Improving the plasticity of thin cold-rolled steel sheet for cold stamping

2016 ◽  
Vol 46 (5) ◽  
pp. 364-367 ◽  
Author(s):  
I. V. Doshchechkina ◽  
S. S. D’yachenko ◽  
I. V. Ponomarenko ◽  
I. S. Tatarkina
Keyword(s):  
Steel Sheet ◽  
Rolled Steel ◽  
Cold Rolled Steel ◽  
Cold Rolled ◽  
Cold Stamping

scholarly journals Numerical simulation of blanking process

2018 ◽  
Vol 157 ◽  
pp. 02038
Author(s):  
Peter Pecháč ◽  
Milan Sága
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Steel Sheet ◽  
Plastic Material ◽  
Material Model ◽  
Rolled Steel ◽  
Finite Element Software ◽  
History Of ◽  
Cold Rolled ◽  
Blanking Process

This paper presents numerical simulation of blanking process for cold-rolled steel sheet metal. The problem was modeled using axial symmetry in commercial finite element software ADINA. Data obtained by experimental measurement were used to create multi-linear plastic material model for simulation. History of blanking force vs. tool displacement was obtained.

scholarly journals Residual Stress in Cold-Rolled Steel Sheet

1990 ◽  
Vol 54 (10) ◽  
pp. 1120-1130 ◽  
Author(s):  
Shigeru Yonetani ◽  
Katsuya Imai ◽  
Hisakimi Notoya
Keyword(s):  
Residual Stress ◽  
Steel Sheet ◽  
Rolled Steel ◽  
Cold Rolled Steel ◽  
Cold Rolled

Model for Predicting the Recrystallized Ferrite Grain Size after Annealing of Cold-Rolled Automobile Body Sheet Steels

2018 ◽  
Vol 2018 (10) ◽  
pp. 968-972
Author(s):  
A. A. Vasilyev ◽  
S. F. Sokolov ◽  
P. S. Zhitelev ◽  
D. F. Sokolov ◽  
N. G. Kolbasnikov ◽  
...  
Keyword(s):  
Grain Size ◽  
Sheet Steels ◽  
Automobile Body ◽  
Cold Rolled ◽  
Ferrite Grain Size
Sign in / Sign up

Export Citation Format

Share Document