Hot ductility trough elimination through single cycle of intense cooling and reheating for microalloyed steel casting

2016 ◽  
Vol 43 (5) ◽  
pp. 331-339 ◽  
Author(s):  
C. Du ◽  
J. Zhang ◽  
J. Wen ◽  
Y. Li ◽  
P. Lan
Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1679
Author(s):  
Chunyu He ◽  
Jianguang Wang ◽  
Yulai Chen ◽  
Wei Yu ◽  
Di Tang

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.


2009 ◽  
Vol 23 (06n07) ◽  
pp. 1122-1128 ◽  
Author(s):  
SUJUAN ZHAO ◽  
QINGFENG WANG ◽  
ZESHENG YAN

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.


2018 ◽  
Vol 115 (4) ◽  
pp. 419 ◽  
Author(s):  
Wenbin Xin ◽  
Jing Zhang ◽  
Guoping Luo ◽  
Ruifen Wang ◽  
Qingyong Meng ◽  
...  

The effect of different Ce content on the hot ductility of C-Mn steel containing arsenic was investigated at the temperature ranging from 700 to 1100 °C conducting Gleebel-1500 thermal-mechanical simulator. The reduction of area (RA%) was used to evaluate the hot ductility. The 0.16 mass% As widened the ductility trough range and especially, decreased the RA value at 850–950 °C. Conversely, adding Ce in the steel could remedy the arsenic-induced hot ductility deterioration. Moreover, with the increase of Ce content from 0 to 0.035 mass%, the RA value at 800–950 °C significantly increased, compared to that of the arsenic steel. When the content of Ce reached 0.027–0.035 mass%, the RA value at 800–850 °C was even higher than that of steel without As. Besides, the corresponding fracture morphology was changed from intergranular feature to ductile and/or interdendritic feature. Grain refinement by Ce addition, the formation of arsenious rare earth inclusions and grain boundary segregation of Ce were considered to improve the hot ductility of the steel containing As.


2015 ◽  
Vol 87 (7) ◽  
pp. 871-879 ◽  
Author(s):  
Martin Lückl ◽  
Ozan Caliskanoglu ◽  
Sergiu Ilie ◽  
Jakob Six ◽  
Ernst Kozeschnik

Author(s):  
Christian HOFLEHNER ◽  
Coline BEAL ◽  
Christof SOMMITSCH ◽  
Jakob SIX ◽  
Sergio ILIE

2015 ◽  
Vol 34 (5) ◽  
Author(s):  
Hong-bing Peng ◽  
Wei-qing Chen ◽  
Lie Chen ◽  
Dong Guo

AbstractThe hot ductility of 20CrMnTi steel with different levels of Cu equivalent was investigated. The results show that Sn and Cu in 20CrMnTi steel are detrimental to its hot ductility. Sn was found to segregate to the boundaries tested by EPMA, moreover, Cu was not found to segregate to boundaries, however, the fracture morphology was examined with SEM and showed many small and shallow dimples on the fracture of steels with large Cu equivalent (>0.15) and fine copper sulfide was found from carbon extraction replicas using TEM. The adverse effect of large Cu equivalent (>0.15) on the hot ductility was due to Sn segregation and fine copper sulfide in the steel as well as their retarding the occurrence of dynamic recrystallization (DRX). The proeutectoid ferrite film precipitating along the austenite grain boundary causes the ductility trough of the five examined steels. Moreover, in this case, the level of Cu equivalent should be controlled below 0.15, which would not deteriorate the hot ductility significantly.


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