Effect of Cool Deformation on the Mechanical Properties of Low C Microalloyed Steels

2008 ◽  
Author(s):  
Jessica Calvo ◽  
Abdelbaset Elwazri ◽  
Dengqi Bai ◽  
Stephen Yue
Keyword(s):  
Mechanical Properties ◽  
Phase Transformation ◽  
Thermomechanical Processing ◽  
Carbon Steels ◽  
Microalloyed Steels ◽  
Low Carbon ◽  
Strengthening Mechanisms ◽  
Rolling Schedule ◽  
Low Carbon Steels ◽  
Carbon Microalloyed

The application of small amounts of deformation at coiling temperatures, i.e. cool deformation, has been shown to be an effective method to improve the mechanical properties of low carbon microalloyed steels. Improvements are related to the effect of cool deformation on strengthening mechanisms such as precipitation, grain refinement and phase transformation. However, it is not clear to what extent mechanical properties will improve when cool deformation is applied after TMP (Thermomechanical Processing). In this work, cool deformation was applied in torsion after a simulation of an industrial rolling schedule to samples of six experimental low carbon steels containing different amounts of Nb, Cu, Mo and Si. In general, it was found that cool deformation improved the mechanical properties of all the steels, and the extent of these improvements was dependent on the chemical composition.

scholarly journals New Technology to Produce 1 GPa Low Carbon Microalloyed Steels from Cast Strip

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 662 ◽  
Author(s):  
Andrii Kostryzhev ◽  
Olexandra Marenych
Keyword(s):  
Mechanical Properties ◽  
Global Economy ◽  
New Technology ◽  
Carbon Steels ◽  
Thin Strip ◽  
Microalloyed Steels ◽  
Accelerated Cooling ◽  
Low Carbon ◽  
Elongation To Failure ◽  
Carbon Microalloyed

Global economy requires steel with further increasing mechanical properties and simultaneously decreasing price. In mass manufacturing three major methods can be used to increase strength: (i) increase microalloying element additions (increases cost), (ii) decrease deformation temperature and (iii) increase cooling rate after high temperature processing (both can be challenging for equipment). Thin strip casting is an effective way to reduce cost as it brings a reduction in number of deformation passes and shortens the production line. However, the mechanical properties can be missed due to insufficient microstructure development. In this article, we investigate a recently proposed technology based on Austenite Conditioning followed by Accelerated Cooling and Warm Deformation (AC2WD). Two low carbon steels microalloyed with either 0.012Ti or 0.1Mo-0.064Nb-0.021Ti (wt.%) were subjected to three processing modifications of the AC2WD-technology with two, one or no deformation of cast microstructure in the austenite temperature field. The Ti- and MoNbTi-steels exhibited 685–765 MPa and 880–950 MPa of the yield stress, 780–840 MPa and 1035–1120 MPa of tensile strength, and 20–30% and 22–24% of elongation to failure, respectively. The nature of strengthening mechanisms associated with the AC2WD-technology is discussed on the basis of detailed microstructure characterisation.

scholarly journals Effect of the Chemical Composition on the Structural State and Mechanical Properties of Complex Microalloyed Steels of the Ferritic Class

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 646 ◽  
Author(s):  
Alexander Zaitsev ◽  
Anton Koldaev ◽  
Nataliya Arutyunyan ◽  
Sergey Dunaev ◽  
Dmitrii D’yakonov
Keyword(s):  
Mechanical Properties ◽  
Structural State ◽  
Strength Properties ◽  
Carbon Steels ◽  
Microalloyed Steels ◽  
Low Carbon ◽  
Low Carbon Steels ◽  
Transmission Electron ◽  
Ferrite Fraction ◽  
Hot Rolled

The most promising direction for obtaining a unique combination of difficult-to-combine properties of low-carbon steels is the formation of a dispersed ferrite microstructure and a volumetric system of nanoscale phase precipitates. This study was aimed at establishing the special features of the composition influence on the characteristics of the microstructure, phase precipitates, and mechanical properties of hot-rolled steels of the ferritic class. It was carried out by transmission electron microscopy and testing the mechanical properties of metal using 8 laboratory melts of low-carbon steels microalloyed by V, Nb, Ti, and Mo in various combinations. It was found that block ferrite prevails in the structure of steel cooled after hot rolling at a rate of 10–15 °C/s. Lowering of the microalloying components content leads to a decrease in the block ferrite fraction to 20–35% and the dominance of polygonal ferrite. The presence of nanoscale carbide (carbonitride) precipitates of austenitic and interphase/mixed types was detected in the rolled steels. It was established that the tendencies of changes in the characteristics of the structural state and present phase precipitates correlate well with obtained values of strength properties. The advantages of titanium-based microalloying systems in comparison with vanadium-based are shown.

scholarly journals Evolution of Microstructure and Precipitation State During Thermomechanical Processing of a Low Carbon Microalloyed Steel

2012 ◽  
Vol 18 (S5) ◽  
pp. 119-120
Author(s):  
P. Valles ◽  
M. Gómez ◽  
S. F. Medina ◽  
A. Pastor ◽  
O. Vilanova
Keyword(s):  
Mechanical Properties ◽  
Acicular Ferrite ◽  
Thermomechanical Processing ◽  
Transformation Products ◽  
Microalloyed Steels ◽  
Accelerated Cooling ◽  
Low Carbon ◽  
Fine Grained ◽  
Increasing Demand ◽  
Carbon Microalloyed

The increasing demand of sources of energy such as oil and natural gas induces at the steel industry a development on low carbon microalloyed steels for pipeline applications in order to achieve excellent mechanical properties of strength and toughness at a reduced cost. To obtain an adequate fine-grained final structure, the strict control of thermomechanical processing and accelerated cooling is crucial. Depending on the thermomechanical processing conditions and chemical composition, pipeline steels can present different microstructures. Several authors have found that the microstructure of acicular ferrite usually provides an optimum combination of mechanical properties. Higher levels of austenite strengthening before cooling promote a refinement of final microstructure but can also restrict the fraction of low temperature transformation products such as acicular ferrite.

The Influence of Oxide Inclusion on the Refinement of Bainite and Toughness in HAZ for Low Carbon Steels

2013 ◽  
Vol 651 ◽  
pp. 163-167
Author(s):  
Shu Rui Li ◽  
Xue Min Wang ◽  
Xin Lai He
Keyword(s):  
Mechanical Properties ◽  
Acicular Ferrite ◽  
Oxide Inclusion ◽  
Optical Microscope ◽  
Carbon Steels ◽  
Low Carbon ◽  
Low Carbon Steels ◽  
The Core ◽  
Ti Oxides ◽  
Bainitic Steels

The influence of Ti oxide on the toughness of heat affected zone for low carbon bainitic steels has been investigated. The optical microscope, SEM and TEM were used to analyze the composition, size and distribution of the inclusions, and the microstructure and mechanical properties after welding thermal simulation were also investigated. The effect of Ti oxide inclusion on the transformation of acicular ferrite has also been studied. The results show that after the melting with Ti dioxide technique the inclusion is complex, in the core is Ti oxides about 1-3 micron and around it is MnS. It has been found the acicular ferrite can nucleate at the inclusions and the Ti oxide inclusion will promote the nucleation of acicular ferrite, and the acicular ferrite will block the growth of bainite. Therefore by introducing the Ti oxide in the steels the microstructure of HAZ could be refined markedly therefore the toughness of HAZ can be improved evidently.

scholarly journals Mechanical Properties of Nb-containing Low-carbon Steels Produced by Direct Rolling

1988 ◽  
Vol 74 (12) ◽  
pp. 2323-2329 ◽  
Author(s):  
Masahiko ODA ◽  
Hiroshi KUBO ◽  
Osamu AKISUE ◽  
Kichi NAKAZAWA
Keyword(s):  
Mechanical Properties ◽  
Carbon Steels ◽  
Low Carbon ◽  
Low Carbon Steels ◽  
Direct Rolling

Deformation, Mechanical Properties, and Fracture of Quenched and Tempered Carbon Steels

2015 ◽  
pp. 405-437
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Ductile Fracture ◽  
Carbon Steels ◽  
Low Carbon ◽  
Tempering Temperature ◽  
Medium Carbon ◽  
Low Carbon Steels ◽  
Deformation Properties ◽  
Medium Carbon Steels

Abstract Steels with martensitic and tempered martensitic microstructures, though sometimes perceived as brittle, exhibit plasticity and ductile fracture behavior under certain conditions. This chapter describes the alloying and tempering conditions that produce a ductile form of martensite in low-carbon steels. It also discusses the effect of tempering temperature on the mechanical behavior and deformation properties of medium-carbon steels.

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