scholarly journals Highly Enhanced Hot Ductility Performance of Advanced SA508-4N RPV Steel by Trace Impurity Phosphorus and Rare Earth Cerium

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1598
Author(s):  
Yu Guo ◽  
Yu Zhao ◽  
Shenhua Song
Keyword(s):  
Single Phase ◽  
Boundary Segregation ◽  
Tensile Tests ◽  
Phase Region ◽  
Hot Ductility ◽  
Hot Workability ◽  
Rpv Steel ◽  
Ductility Trough ◽  
Boundary Sliding ◽  
Reduction Of Area

Advanced SA508-4N RPV steel samples, unadded, P-added, and P+Ce-added, are investigated on their hot ductility behavior. Hot tensile tests are carried out in the temperature range of 750 to 1000 °C through a Gleeble 1500D machine. It is demonstrated that the deformation temperatures of all the three steels are located in the austenite single-phase region. There is no ductility trough present for the P+Ce-added steel, but the unadded one exhibits a deep ductility trough. The reduction of area (RA) of the former is always higher than 75% and increases with rising temperature until reaching ~95% at 900 °C or above, whereas the lowest RA value of the latter is only ~50% at 850 °C. Microanalysis indicates that the grain boundary segregation of P and Ce takes place in the tested P+Ce-added steel. This may restrain the boundary sliding so as to improve the hot ductility behavior of the steel. Furthermore, the addition of P and Ce is able to facilitate the occurrence of the dynamic recrystallization (DR) of the steel, lowering the initial temperature of DR from ~900 to ~850 °C and thereby enhancing the hot ductility performance. Consequently, the combined addition of P and Ce can significantly improve the hot ductility of SA508-4N RPV steel, thereby improving its continuous casting performance and hot workability.

Improvement of hot ductility of C-Mn Steel containing arsenic by rare earth Ce

2018 ◽  
Vol 115 (4) ◽  
pp. 419 ◽  
Author(s):  
Wenbin Xin ◽  
Jing Zhang ◽  
Guoping Luo ◽  
Ruifen Wang ◽  
Qingyong Meng ◽  
...  
Keyword(s):  
Rare Earth ◽  
Grain Boundary ◽  
Boundary Segregation ◽  
Fracture Morphology ◽  
Grain Boundary Segregation ◽  
Hot Ductility ◽  
Ductility Trough ◽  
Reduction Of Area ◽  
Mn Steel ◽  
Ce Content

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.

Relevance of Hot Ductility Tests to Crack Sensitivity during Continuous Casting of Steel

2014 ◽  
Vol 922 ◽  
pp. 201-206
Author(s):  
Simon Großeiber ◽  
Christian Gusenbauer ◽  
Sergiu Ilie ◽  
Guillermo C. Requena ◽  
Ernst Kozeschnik
Keyword(s):  
Strain Rate ◽  
Tensile Tests ◽  
Phase Region ◽  
Austenite Phase ◽  
Hot Ductility ◽  
Strain Rates ◽  
X Ray ◽  
X Ray Computed ◽  
Reduction Of Area ◽  
Critical Reduction

Hot tensile tests are performed on a Ni-alloyed steel after solution treating and cooling to test temperatures ranging between 600 and 950°C at strain rates of 3∙10-4and 3∙10-3/s. The critical reduction of area (RA) for damage formation is determined by means of laboratory X-ray computed tomography. The results are compared with the corresponding RA at fracture traditionally used for assessing hot ductility and crack sensitivity during straightening of the slab. We demonstrate that using RA at fracture is inadequate for evaluating hot ductility in the austenite phase region at temperatures varying with the strain rate. Hot ductility curves more relevant for slow strain rate deformation are determined.

Elevated Temperature Mechanical Properties of Devitrified Metallic Glass

2004 ◽  
Vol 821 ◽  
Author(s):  
Nathan A. Mara ◽  
Alla V. Sergueeva ◽  
A.K. Mukherjee
Keyword(s):  
Elevated Temperature ◽  
Metallic Glass ◽  
Grain Growth ◽  
Single Phase ◽  
Tensile Tests ◽  
Grain Boundary Sliding ◽  
Brittle Behavior ◽  
Materials Research ◽  
Boundary Sliding ◽  
Research Grant

AbstractElevated temperature tensile tests of different microstructures arising from different heat treatments of the Fe-based metallic glass Vitroperm (Fe73.5Cu1Nb3Si15.5B7) are presented. An anneal at 600°C for 1h yields a single phase μ-Fe microstructure with equiaxed, randomly oriented 15 nm grains, which is an ideal candidate for study of material properties at diminishing length scale. This microstructure has good stability during tensile testing at 600°C, showing a strain rate exponent correlating to grain boundary sliding (m=0.5), but little ductility, and strengths to 1250 MPa. The brittle behavior could be attributed to the lack of dislocation activity at such length scales. At temperatures up to 725°C, grain growth occurs, leading to elongations as large as 65% at flow stresses of 250 MPa. Precipitation of a second Nb-rich phase accompanies the grain growth. This investigation is supported by NSF, Division of Materials Research, grant NSF-DMR-0240144.

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 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 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 New Approach In The Properties Evaluation Of Ultrafine-Grained OFHC Copper

2015 ◽  
Vol 60 (2) ◽  
pp. 605-614 ◽  
Author(s):  
T. Kvačkaj ◽  
A. Kováčová ◽  
J. Bidulská ◽  
R. Bidulský ◽  
R. Kočičko
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Tensile Tests ◽  
Coarse Grained ◽  
Wear Behaviour ◽  
Ofhc Copper ◽  
Strain Rates ◽  
Ultrafine Grained ◽  
Reduction Of Area ◽  
Pin On Disk

AbstractIn this study, static, dynamic and tribological properties of ultrafine-grained (UFG) oxygen-free high thermal conductivity (OFHC) copper were investigated in detail. In order to evaluate the mechanical behaviour at different strain rates, OFHC copper was tested using two devices resulting in static and dynamic regimes. Moreover, the copper was subjected to two different processing methods, which made possible to study the influence of structure. The study of strain rate and microstructure was focused on progress in the mechanical properties after tensile tests. It was found that the strain rate is an important parameter affecting mechanical properties of copper. The ultimate tensile strength increased with the strain rate increasing and this effect was more visible at high strain rates$({\dot \varepsilon} \sim 10^2 \;{\rm{s}}^{ - 1} )$. However, the reduction of area had a different progress depending on microstructural features of materials (coarse-grained vs. ultrafine-grained structure) and introduced strain rate conditions during plastic deformation (static vs. dynamic regime). The wear behaviour of copper was investigated through pin-on-disk tests. The wear tracks examination showed that the delamination and the mild oxidational wears are the main wear mechanisms.

Structure of Low Cobalt Alloy for Permanent Magnets of Basis System Fe-Cr-Co at Complex Two-Level Loading in Isothermal Conditions

2007 ◽  
Vol 539-543 ◽  
pp. 2928-2933 ◽  
Author(s):  
V.S. Yusupov ◽  
A.I. Milyaev ◽  
Galia F. Korznikova ◽  
Alexander V. Korznikov ◽  
J.K. Kovneristii
Keyword(s):  
Grain Size ◽  
Active Zone ◽  
Single Phase ◽  
Permanent Magnets ◽  
Phase Region ◽  
The Body ◽  
Coarse Grained ◽  
Isothermal Conditions ◽  
Basis System ◽  
Level Loading

Results of experimental research into evolution of the structure and microhardness of the hard magnetic Fe-30Cr-8Co-0,7Ti-0,5V-0,7Si alloy during complex two-level loading (compression + torsion) in isothermal conditions at various temperatures in single-phase region are reported. It was revealed that the deformation leads to a strong refinement of initial coarse-grained structure in the whole volume of the sample, however the generated structure is non-uniform through the body of the sample. In an active zone of deformation, near to mobile head, there is a microcrystalline layer with a grain size of about 5 microns which thickness poorly depends on the formation. With removal from the active zone of deformation the grain size increases, and microhardness decreases.

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