Tensile test on in situ solidified notched specimens: effects of temperature history and strain rate on the hot ductility of Nb and NbV microalloyed steels

1993 ◽  
Vol 168 (1) ◽  
pp. 17-22 ◽  
Author(s):  
P. Deprez ◽  
J.P. Bricout ◽  
J. Oudin
Keyword(s):  
Tensile Test ◽  
Strain Rate ◽  
Temperature History ◽  
Microalloyed Steels ◽  
Hot Ductility ◽  
Notched Specimens ◽  
Effects Of Temperature

scholarly journals In situ Solidified Hot Tensile Test and Hot Ductility of Some Plain Carbon Steels and Microalloyed Steels.

1994 ◽  
Vol 34 (6) ◽  
pp. 528-535 ◽  
Author(s):  
Thierry Revaux ◽  
Pascal Deprez ◽  
Jean-Paul Bricout ◽  
Jérôme Oudin
Keyword(s):  
Tensile Test ◽  
Carbon Steels ◽  
Microalloyed Steels ◽  
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.

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.

scholarly journals Hot Workability of 300M Steel Investigated by In Situ and Ex Situ Compression Tests

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 880 ◽  
Author(s):  
Rongchuang Chen ◽  
Haifeng Xiao ◽  
Min Wang ◽  
Jianjun Li
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Hot Working ◽  
Ex Situ ◽  
Lower Strain Rate ◽  
Hot Workability ◽  
Compression Tests ◽  
300M Steel ◽  
Lower Strain

In this work, hot compression experiments of 300M steel were performed at 900–1150 °C and 0.01–10 s−1. The relation of flow stress and microstructure evolution was analyzed. The intriguing finding was that at a lower strain rate (0.01 s−1), the flow stress curves were single-peaked, while at a higher strain rate (10 s−1), no peak occurred. Metallographic observation results revealed the phenomenon was because dynamic recrystallization was more complete at a lower strain rate. In situ compression tests were carried out to compare with the results by ex situ compression tests. Hot working maps representing the influences of strains, strain rates, and temperatures were established. It was found that the power dissipation coefficient was not only related to the recrystallized grain size but was also related to the volume fraction of recrystallized grains. The optimal hot working parameters were suggested. This work provides comprehensive understanding of the hot workability of 300M steel in thermal compression.

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