Microalloying effects on structure-forming processes during hot plastic deformation

2021 ◽  
pp. 5-16
Author(s):  
S. V. Korotovskaya ◽  
O. V. Sych ◽  
E. I. Khlusova ◽  
N. S. Novoskoltsev
Keyword(s):  
Plastic Deformation ◽  
Deformation Temperature ◽  
Thermal Deformation ◽  
Static Recrystallization ◽  
High Strength Steels ◽  
High Strength ◽  
Homogeneous Structure ◽  
Hot Plastic Deformation ◽  
Austenite Grains ◽  
Kinetics Of

The kinetics of austenite grains' growth upon heating has been investigated, and the processes of dynamic and static recrystallization occurring under different modes of plastic deformation (reduction pattern, deformation temperature) of high-strength steels with various microalloying complexes have been studied. The research made it possible to reveal the thermal deformation conditions for the formation of a finely dispersed homogeneous structure of steel. Technological recommendations have been developed for the production of high-strength steels depending on their microalloying (vanadium, niobium).

Influence of niobium microalloying on the kinetics of static and dynamic recrystallization during hot rolling of medium-carbon high-strength steels

2020 ◽  
pp. 5-15
Author(s):  
T. V. Knyazyuk ◽  
N. S. Novoskoltsev ◽  
A. A. Zisman ◽  
E. I. Khlusova
Keyword(s):  
Dynamic Recrystallization ◽  
Hot Rolling ◽  
Static Recrystallization ◽  
High Strength Steels ◽  
High Strength ◽  
Medium Carbon Steel ◽  
Medium Carbon ◽  
Niobium Microalloying ◽  
Temperature Strain ◽  
Kinetics Of

The temperature-strain conditions of dynamic and static recrystallization during hot deformation were determined at a rate of 1 sec–1 for medium-carbon steel microalloyed with titanium, boron, and vanadium containing different amounts of niobium. It was found that under hot rolling conditions niobium prevents the completion of dynamic recrystallization, and at temperatures below 970°C it drastically slows down static recrystallization in the pauses between successive reductions.

Development of thermal rolling regimes of low-alloy “ARC”-steel with quasi-homogeneous ferrite-bainitic structure

2021 ◽  
pp. 7-20
Author(s):  
O. V. Sych ◽  
S. V. Korotovskaya ◽  
E. I. Khlusova ◽  
N. S. Novoskoltsev
Keyword(s):  
Thermal Deformation ◽  
Static Recrystallization ◽  
Temperature Deformation ◽  
Structure And Properties ◽  
Deformation Parameters ◽  
Bainitic Structure ◽  
Austenite Grains ◽  
Sheet Products ◽  
Deformation Modes ◽  
Kinetics Of

In this work, the kinetics of the growth of austenite grains upon heating, the features of the processes of dynamic and static recrystallization occurring at various temperature-deformation modes of plastic deformation are investigated. Phase transformations have been studied during continuous cooling of hotdeformed austenite in low-alloy “Arc”-steel with a yield point of at least 420 MPa. The studies carried out made it possible to determine the thermal deformation parameters that ensure the formation of a finely dispersed homogeneous ferrite-bainitic structure, on the basis of which technological recommendations for industrial production were developed and sheet products were manufactured. Presented are the structure and properties of sheet metal from shipbuilding “Arc”-strength category 420 MPa.

scholarly journals Enhancing the Mechanical Properties of a Hot Rolled High-Strength Steel Produced by Ultra-Fast Cooling and Q&P Process

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 958 ◽  
Author(s):  
Teng Wu ◽  
Run Wu ◽  
Bin Liu ◽  
Wen Liang ◽  
Deqing Ke
Keyword(s):  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
Controlled Rolling ◽  
Grain Structure ◽  
Ultra Fast Cooling ◽  
Advanced High Strength Steels ◽  
Fast Cooling ◽  
Austenite Grains ◽  
Hot Rolled

The quenching and partitioning (Q&P) process of advanced high strength steels results in a significant enhancement in their strength and ductility. The development of controlled rolling and cooling technology provides an efficient tool for microstructural design in steels. This approach allows to control phase transformations in order to generate the desired microstructure in steel and, thus, to achieve the required properties. To refine grain structure in a Fe-Si-Mn-Nb steel and to generate the microstructure consisting of martensitic matrix with embedded retained austenite grains, hot rolling and pressing combined with ultrafast cooling and Q&P process is employed. The slender martensite in hot rolled Q&P steel improves the strength of test steel and the flake retained austenite improves the plasticity and work hardening ability through the Transformation Induced Plasticity (TRIP) effect.

Characteristics of the Static Recrystallization Kinetics of an Intercritically Deformed C-Mn Steel

2004 ◽  
Vol 467-470 ◽  
pp. 293-298 ◽  
Author(s):  
Haiwen Luo ◽  
Jilt Sietsma ◽  
Sybrand van der Zwaag
Keyword(s):  
Stress Relaxation ◽  
Static Recrystallization ◽  
Avrami Exponent ◽  
Recrystallization Kinetics ◽  
Ferrite Fraction ◽  
Austenite Recrystallization ◽  
Austenite Grains ◽  
Intercritical Region ◽  
Mn Steel ◽  
Kinetics Of

The austenite recrystallization kinetics in the intercritical region of a C-Mn steel is investigated by means of stress relaxation tests. It is found that the Avrami exponent, n, decreases significantly with decreasing temperature, i.e. with increasing ferrite fraction. This behaviour deviates from that of austenite recrystallization in the purely austenitic state, in which case the Avrami exponent is constant and independent of temperature and deformation. To interpret this, the influence of spatial variation of the plastic strain in the intercritical austenite grains on recrystallization kinetics is modelled quantitatively. The modelling results seem to indicate that the strain heterogeneity is responsible for the decreasing Avrami exponent with decreasing intercritical temperature.

Influence of Plastic Deformation of the Heat Affected Zone on the Mechanical Behaviour of Welds in High Strength Steels

2003 ◽  
Vol 233-236 ◽  
pp. 791-796
Author(s):  
Dulce Maria Rodrigues ◽  
Luís Filipe Menezes ◽  
Altino Loureiro ◽  
José Valdemar Fernandes
Keyword(s):  
Plastic Deformation ◽  
Mechanical Behaviour ◽  
Heat Affected Zone ◽  
High Strength Steels ◽  
High Strength

Studies of SCC and Hydrogen Embrittlement of High Strength Alloys Using Fracture Mechanics Methods

2005 ◽  
Vol 482 ◽  
pp. 11-16 ◽  
Author(s):  
Wolfgang Dietzel ◽  
Michael Pfuff ◽  
Guido G. Juilfs
Keyword(s):  
Plastic Deformation ◽  
Fracture Mechanics ◽  
Hydrogen Embrittlement ◽  
Hydrogen Diffusion ◽  
High Strength Steels ◽  
High Strength ◽  
Constant Load ◽  
Rate Of Change ◽  
Extension Rate ◽  
Hydrogen Atoms

Fracture mechanics based test and evaluation techniques are used to gain insight into the phenomenon of stress corrosion cracking (SCC) and to develop guidance for avoiding or controlling SCC. Complementary to well known constant load and constant deflection test methods experiments that are based on rising load or rising displacement situations and are specified in the new ISO standard 7539 – Part 9 may be applied to achieve these goals. These are particularly suitable to study cases of SCC and hydrogen embrittlement of high strength steels, aluminium and titanium alloys and to characterise the susceptibility of these materials to environmentally assisted cracking. In addition, the data generated in such R-curve tests can be used to model the degradation of the material caused by the uptake of atomic hydrogen from the environment. This is shown for the case of a high strength structural steel (FeE 690T) where in fracture mechanics SCC tests on pre-cracked C(T) specimens a correlation between the rate of change in plastic deformation and the crack extension rate due to hydrogen embrittlement was established. The influence of plastic strain on the hydrogen diffusion was additionally studied by electrochemical permeation experiments. By modelling this diffusion based on the assumption that trapping of the hydrogen atoms takes place at trap sites which are generated by the plastic deformation, a good agreement was achieved between experimentally obtained data and model predictions.

Strain Hardening Behaviour of PM Alloys with Heterogeneous Microstructure

2007 ◽  
Vol 534-536 ◽  
pp. 741-744 ◽  
Author(s):  
Giovanni Straffelini
Keyword(s):  
Plastic Deformation ◽  
Strain Hardening ◽  
Flow Behavior ◽  
High Strength Steels ◽  
High Strength ◽  
Acoustic Resonance ◽  
Matrix Microstructure ◽  
The Matrix ◽  
Heterogeneous Matrix ◽  
Localized Plastic Deformation

Tensile stress-strain and dynamic acoustic resonance tests were performed on Fe-C-Ni- Cu-Mo high-strength steels, characterized by a heterogeneous matrix microstructure and the prevalence of open porosity. All materials display the first yielding phenomenon and, successively, a continuous yielding behavior. This flow behavior can be described by the Ludwigson equation and developes through three stages: the onset of localized plastic deformation at the pore edges; the evolution of plastic deformation at the pore necks (where the austenitic Ni-rich phase is predominant); the spreading of plastic deformation in the interior of the matrix. The analytical modeling of the strain hardening behavior made it possible to obtain the boundaries between the different deformation stages.

Effect of Coiling Temperature on Kinetics of Austenite Formation in Cold Rolled Advanced High Strength Steels

2012 ◽  
Vol 706-709 ◽  
pp. 2112-2117 ◽  
Author(s):  
R.R. Mohanty ◽  
O.A. Girina
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Continuous Heating ◽  
Austenite Formation ◽  
Continuous Annealing ◽  
Hard Material ◽  
Low Carbon ◽  
Coiling Temperature ◽  
Hot Rolled ◽  
Kinetics Of

A systematic experimental investigation was conducted using lab processed low carbon 0.08C-2.0Mn-Cr-Mo steel microalloyed with Ti/Nb to evaluate the influence of initial hot-rolled microstructures on the kinetics of austenite formation and decomposition after cold-rolling and subsequent annealing. Coiling temperature as a major hot rolling parameter was used to obtain different types of hot-rolled microstructures. Dilatometer and continuous annealing simulator were employed for austenite formation studies and annealing simulations, respectively. It was found that the coiling temperature affects the processes occurring during heat treatment in continuous annealing lines of full hard material: ferrite recrystallization, austenite formation during continuous heating and austenite decomposition during cooling. A decrease in coiling temperature accelerates the recrystallization of ferrite and nucleation of austenite, which results in formation of refined ferrite-martensite structure. The effect of initial hot rolled structure on final mechanical properties after continuous annealing was also investigated.

Sign in / Sign up

Export Citation Format

Share Document