scholarly journals Effect of Vanadium and Strain Rate on Hot Ductility of Low-Carbon Microalloyed Steels

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 14
Author(s):  
Siying Song ◽  
Junyu Tian ◽  
Juan Xiao ◽  
Lei Fan ◽  
Yuebiao Yang ◽  
...  
Keyword(s):  
Strain Rate ◽  
Tensile Tests ◽  
Vanadium Content ◽  
Microalloyed Steels ◽  
Hot Ductility ◽  
Low Carbon ◽  
Temperature Range ◽  
Ferrite Transformation ◽  
Ductility Trough ◽  
Carbon Microalloyed

Hot tensile tests were conducted in this study to investigate the effect of strain rate (10−3 and 10 s−1) and vanadium content (0.029 and 0.047 wt.%) on the hot ductility of low-carbon microalloyed steels. The results indicate that a hot ductility trough appears at a low strain rate (10−3 s−1) because of the sufficient time for ferrite transformation and the growth of second particles, but it disappears at a high strain rate (10 s−1). The hot ductility is improved with the increase in strain rate at 700 °C or higher temperatures. In addition, with the increase in vanadium content, the large amounts of precipitate and increased ferrite transformation result in poor hot ductility of steels fractured at a low temperature range (600~900 °C). However, when the steel is fractured at a high temperature range (1000~1200 °C), more vanadium in the solid solution in the austenite inhibits the growth of parental austenite grains and results in grain refinement strengthening, slightly improving the hot ductility.

INFLUENCE OF NITROGEN ON HOT DUCTILITY BEHAVIOR OF MEDIUM CARBON MICROALLOYED STEEL

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1122-1128 ◽  
Author(s):  
SUJUAN ZHAO ◽  
QINGFENG WANG ◽  
ZESHENG YAN
Keyword(s):  
Microalloyed Steel ◽  
True Strain ◽  
Tensile Tests ◽  
Microalloyed Steels ◽  
Hot Ductility ◽  
True Strain Rate ◽  
Medium Carbon ◽  
Ductility Trough ◽  
Carbon Microalloyed

The current study aims to estimate the influence of enhanced nitrogen on the hot ductility of medium carbon microalloyed steel. For this purpose, hot tensile tests were carried out at temperatures rangeing from 700°C-1000°C at a true strain rate of 0.001s-1. The fracture surfaces and their neighboring precipitates and matrix microstructures "frozen" in tensile temperatures were observed. The dependence of hot ductility on the fracture mode and in situ microstructural changes were discussed. The results indicate that raising the nitrogen content from 0.003% to 0.014% and 0.021% was found to deteriorate the ductility as the obtained ductility trough became deeper and wider. The trough deepening caused by the addition of nitrogen was due to the formation of film-like ferrite and fine VN precipitation along the austenite grain boundaries promoting low ductility intergranular failure. On the other hand, the retarded dynamic recrystallization, the promoted deformation induced ferrite formation and precipitation at higher temperatures by enhanced nitrogen were regarded as the possible reasons for a wider trough. In summary, the above results indicate the hot ductility of medium carbon microalloyed steels is weakened to some extent by enhanced nitrogen and their windows suitable for continuous casting should be schemed very carefully.

Effect of Nb and V in the Development of Texture and Plastic Strain Ratio in Low Carbon Microalloyed Steels Produced by A.S.T. Technology

2005 ◽  
Vol 500-501 ◽  
pp. 279-286
Author(s):  
Carlo Mapelli ◽  
Roberto Venturini ◽  
Antonio Guindani
Keyword(s):  
Mechanical Properties ◽  
Strain Ratio ◽  
Tensile Tests ◽  
Microalloyed Steels ◽  
Low Carbon ◽  
Plastic Strain Ratio ◽  
Steel Technology ◽  
Back Scattering ◽  
Carbon Microalloyed ◽  
Hot Rolled

The effects of Nb and V on the anisotropy and textures featuring the hot rolled low carbon microalloyed steels produced by A.S.T. (Arvedi Steel Technology) have been studied as a function of the final coiling temperatute Tcoiling. Mechanical properties and r-values for twelve steels have been determined through tensile tests performed on three main different directions: 0°, 45°, 90° to the rolling one. The samples have been analysed by EBSD (Electron Back Scattering Diffraction) to identify the textures developed during the process. The relations among the chemical composition of the steels (i.e. C, N, Nb, V contents), the mechanical properties, the temperature during the coiling operations, the textures and the formability properties have been pointed out.

scholarly journals Effects of composition and strain rate on hot ductility of Cr–Mo-alloy steel in the two-phase region

2021 ◽  
Vol 40 (1) ◽  
pp. 228-240
Author(s):  
Yaxu Zheng ◽  
Wei Shen ◽  
Liguang Zhu ◽  
Zhihong Guo ◽  
Qi Wang ◽  
...  
Keyword(s):  
Strain Rate ◽  
Alloy Steel ◽  
Tensile Tests ◽  
Phase Region ◽  
Hot Ductility ◽  
Strain Rates ◽  
Sufficient Time ◽  
Two Phase ◽  
Obvious Effect ◽  
Ferrite Transformation

Abstract The hot tensile tests were conducted in this study to investigate the effects of Nb, B, Mo, and V on hot ductility of 25CrMo alloy steel in a temperature range of 650–850°C with strain rates of 0.005 and 0.5 s−1. Besides, the influences of ferrite transformation and precipitates on hot ductility were also investigated by the use of SEM and TEM. Thermo-Calc and J Mat Pro were used for calculating equilibrium precipitates and CCT curves, respectively. The results indicated that the hot ductility is deteriorated with the addition of 0.04% Nb due to Nb(C,N) particles and ferrite transformation. The addition of B inhibits ferrite transformation and improves hot ductility. The hot ductility is improved with increasing strain rate from 0.005 to 0.5 s−1 due to the nucleation and growth behavior of ferrite. The fast strain rate promotes nucleation of ferrite; however, the ferrite has no sufficient time to grow up. The addition of Mo inhibits ferrite transformation and improves hot ductility. The addition of 0.12% V has no obvious effect on ferrite transformation. The hot ductility has deteriorated a little with the addition of 0.12% V due to the solution V that increases stress during hot deformation.

scholarly journals Mechanical and Microstructural Investigations of the Laser Welding of Different Zinc-Coated Steels

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 91 ◽  
Author(s):  
Eva Zdravecká ◽  
Ján Slota
Keyword(s):  
Mechanical Properties ◽  
Laser Welding ◽  
Heat Affected Zone ◽  
Microstructural Analysis ◽  
Welding Process ◽  
Tensile Tests ◽  
Microalloyed Steels ◽  
Low Carbon ◽  
Tailor Welded Blanks ◽  
Carbon Microalloyed

Tailor welded blanks (TWB) represent an anisotropic and non-homogenous material. The knowledge of the mechanical properties and microstructure of the fusion zone and heat-affected zone (HAZ) obtained with laser welding is essential to ensure the reliability of the process. In this paper, laser-welded hot-dip Zn-coated low carbon microalloyed steels with different thickness and mechanical properties were used. The mechanical properties of the laser-welded blanks were determined by tensile tests and formability by Erichsen cupping tests. In addition, the pore formation during the laser welding process was analyzed. The microstructural analysis confirmed the formation of the favorable structure of the weld metal and the heat-affected zone without the presence of martensite. The obtained results showed that it is possible to produce TWBs with suitable mechanical properties by laser welding.

Effect of Mo Concentration on Dynamic Recrystallization Behavior of Low Carbon Microalloyed Steels

2013 ◽  
Vol 84 (12) ◽  
pp. 1191-1195 ◽  
Author(s):  
Thomas Schambron ◽  
Liang Chen ◽  
Taliah Gooch ◽  
Ali Dehghan-Manshadi ◽  
Elena V. Pereloma
Keyword(s):  
Dynamic Recrystallization ◽  
Microalloyed Steels ◽  
Recrystallization Behavior ◽  
Low Carbon ◽  
Dynamic Recrystallization Behavior ◽  
Carbon Microalloyed

The hot ductility behaviour of C—Mn—Nb—Al steels and its relation to crack propagation during the straightening of concast strand

1980 ◽  
Vol 295 (1413) ◽  
pp. 124-124
Keyword(s):  
Crack Propagation ◽  
Beneficial Effect ◽  
Surface Crack ◽  
Base Composition ◽  
Tensile Tests ◽  
Hot Ductility ◽  
Percentage Reduction ◽  
Temperature Range ◽  
Solution Treated ◽  
Reduction In Area

As most continuous casters used curved moulds, the as-cast strand must have sufficient hot ductility to survive the straightening operation without cracking. The influence of composition on the tendency for surface crack propagation to occur on straightening of concast strand of a commercial C—Mn-Nb-Al grade of steel, has been examined and compared with the hot ductility behaviour as measured by Gleeble tensile tests. Samples of steel with a nominal base composition of 0.15% C, 1.4% Mn, 0.03% Nb, 0.005 % N but having soluble A1 in the range < 0.01-0.07 % and P in the range 0.01-0.03 % have been solution treated to 1330 °C, cooled to test temperature and strained to fracture in the temperature range 1000-700 °C. The percentage reduction in area passed through a minimum in the temperature range 750-800 °C. Of the elements examined, soluble A1 was found to be the most deleterious to ductility for test temperatures above 850 °C. The niobium addition tended to reduce hot ductility most significantly for temperatures below 850 °C. Phosphorus, surprisingly, was found to have a small beneficial effect on hot ductility.

scholarly journals Effects of Sn and Sb on the Hot Ductility of Nb+Ti Microalloyed Steels

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1679
Author(s):  
Chunyu He ◽  
Jianguang Wang ◽  
Yulai Chen ◽  
Wei Yu ◽  
Di Tang
Keyword(s):  
Laser Scanning ◽  
Microalloyed Steel ◽  
Confocal Laser Scanning Microscope ◽  
Microalloyed Steels ◽  
Confocal Laser ◽  
Hot Ductility ◽  
High Temperature Mechanical Properties ◽  
Ductility Trough ◽  
Gleeble 3500 ◽  
Fracture Morphologies

Referencing the composition of a typical Nb+Ti microalloyed steel (Q345B), two kinds of steels, one microalloyed with Sn and Sb, and the other one only microalloyed with Sb were designed to study the effects of Sn and Sb on the hot ductility of Nb+Ti microalloyed steels. The Gleeble-3500 tester was adopted to determine the high-temperature mechanical properties of the two test steels. Fracture morphologies, microstructures and interior precipitation status were analyzed by SEM, CLSM (Confocal laser scanning microscope) and EDS, respectively. Results revealed that within the range of 950–650 °C, there existed the ductility trough for the two steels, which were mainly attributed to the precipitation of TiN and Nb (C, N). Additionally, precipitation of Sn and Sb were not observed in this research and the hot ductility was not affected by the addition of Sn and Sb, as compared with the Nb+Ti microalloyed steel. Therefore, addition of a small amount of Sn and Sb (≤0.05 wt.%) to the Nb+Ti microalloyed steel is favorable due to the improvement on corrosion resistance.

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