FRACTURE RESISTANCE OF “TRANSITION” AREA IN THREE-LAYER STEEL/VANADIUM ALLOY/STEEL COMPOSITE AFTER THERMOMECHANICAL TREATMENT

2018 ◽  
Vol 61 (6) ◽  
pp. 447-453
Author(s):  
T. A. Nechaikina ◽  
S. A. Nikulin ◽  
S. O. Rogachev ◽  
V. Yu. Turilina ◽  
A. P. Baranova
Keyword(s):  
Chemical Composition ◽  
Fast Neutron ◽  
Alloy Steel ◽  
Thermomechanical Treatment ◽  
Fracture Resistance ◽  
Continuous Series ◽  
Vanadium Alloy ◽  
Layer Material ◽  
Transition Area ◽  
Diffusion Interaction

The creation of new structural materials for cladding tubes  of fast neutron reactors is an urgent task of modern nuclear power  engineering. A three-layer radiation-resistant and corrosion-resistant material based on vanadium alloy and stainless steel, intended  for work under extreme conditions (high temperatures, radiation  and aggressive environment) of operation of fast neutron reactor  cladding tubes has been developed in recent years. The most important aspect determining the operability of this material during  operation is the quality of the joining of different materials layers  among themselves, determined by the modes of thermomechanical treatment. The effect of the annealing on the chemical composition, structure, and fracture resistance of the “steel/vanadium  alloy” interface in the steel/vanadium alloy/steel three-layer tube,  obtained by hot co-extrusion of three-layer tube billet at 1100  °C  was studied. The 20Kh13 (AISI 420 type) steel for the outer layers and V – 4Ti – 4Cr vanadium alloy for the core were used as the  components of the tube. The structure and chemical composition  in the layer joining zone were studied using the optical microscopy and electron microscopy with X-ray microspectral analysis.  The fracture resistance of the “steel/vanadium alloy” interface was  evaluated by a compression test of a three-layer ring sample with  notch using an acoustic emission (AE) measurement. It is shown  that after co-extrusion a “transition” area of diffusion interaction  having a variable chemical composition with a width of 10–15 μm  is formed between vanadium alloy and steel, which represents the  continuous series of solid solutions, without precipitation of brittle  phases, providing a strong bonding between vanadium alloy and  steel in the three-layer material. No voids, delaminations or defects were detected at the “steel/vanadium alloy” interface. However, a  crack is formed in the steel layer during the compression tests of  the notched semi-ring three-layer samples after hot co-extrusion.  Annealing favorably influences the formation of the “transition”  area due to the increase in the width of the diffusion interaction  area. No cracks or delaminations at the boundary between steel and  vanadium layers were observed in the three-layer tube samples after annealing, and the three-layer material behaves like a monolith  material during testing.

Thermomechanical Treatment of a 4340 Ni-Cr-Mo Alloy Steel

1981 ◽  
Vol 39 ◽  
pp. 314-315 ◽  
Author(s):  
M.T. Jahn ◽  
J.C. Yang ◽  
C.M. Wan
Keyword(s):  
Mechanical Property ◽  
Chemical Composition ◽  
Alloy Steel ◽  
Thermomechanical Treatment ◽  
Room Temperature ◽  
Good Combination ◽  
Thermal Treatments ◽  
Low Carbon ◽  
4340 Steel ◽  
Good Improvement

4340 Ni-Cr-Mo alloy steel is widely used due to its good combination of strength and toughness. The mechanical property of 4340 steel can be improved by various thermal treatments. The influence of thermomechanical treatment (TMT) has been studied in a low carbon Ni-Cr-Mo steel having chemical composition closed to 4340 steel. TMT of 4340 steel is rarely examined up to now. In this study we obtain good improvement on the mechanical property of 4340 steel by TMT. The mechanism is explained in terms of TEM microstructures4340 (0.39C-1.81Ni-0.93Cr-0.26Mo) steel was austenitized at 950°C for 30 minutes. The TMTed specimen (T) was obtained by forging the specimen continuously as the temperature of the specimen was decreasing from 950°C to 600°C followed by oil quenching to room temperature. The thickness reduction ratio by forging is 40%. The conventional specimen (C) was obtained by quenching the specimen directly into room temperature oil after austenitized at 950°C for 30 minutes. All quenched specimens (T and C) were then tempered at 450, 500, 550, 600 or 650°C for four hours respectively.

Stability of the Transition Zones in a Steel–Vanadium Alloy–Steel Sandwich after Thermomechanical Treatment

2018 ◽  
Vol 48 (6) ◽  
pp. 346-351
Author(s):  
T. A. Nechaikina ◽  
S. A. Nikulin ◽  
S. O. Rogachev ◽  
V. Yu. Turilina ◽  
A. P. Baranova
Keyword(s):  
Alloy Steel ◽  
Thermomechanical Treatment ◽  
Vanadium Alloy ◽  
Transition Zones

scholarly journals Effects of thermomechanical treatment on the occurrence of coincident site lattice boundaries in high strength low alloy steel

2013 ◽  
Vol 16 (6) ◽  
pp. 1350-1354 ◽  
Author(s):  
Renato Soares de Castro ◽  
Ricardo Artur Sanguinetti Ferreira ◽  
Igor Rafael Vilarouco Pedrosa ◽  
Yogendra Prasad Yadava
Keyword(s):  
Alloy Steel ◽  
Thermomechanical Treatment ◽  
Coincident Site Lattice ◽  
High Strength ◽  
Low Alloy Steel ◽  
Site Lattice

scholarly journals Structure and phase composition of material based on vanadium alloy V-4.9Ti-4.8Cr and ferrite steel 17Cr-12Ni-Fe

2018 ◽  
Vol 243 ◽  
pp. 00019
Author(s):  
Taras Dement ◽  
Irina Kurzina ◽  
Mark Kalashnikov ◽  
Natalia Popova ◽  
Natalia Karakchieva
Keyword(s):  
Phase Composition ◽  
Thermal Treatment ◽  
Uniform Distribution ◽  
Transition Zone ◽  
Vanadium Alloy ◽  
Layer Material ◽  
Direct Laser ◽  
Before And After ◽  
Additional Thermal Treatment ◽  
Ferrite Steel

Three-layer materials consisting of the V-4.9Ti-4.8Cr/ferrite steel 17Cr-12Ni-Fe /V-4.9Ti-4.8Cr were obtained in the paper. Phase composition and microstructure of the transition zone of the three-layer material of vanadium alloy V-4.9Ti-4.8Cr and ferrite steel 17Cr-12Ni-Fe were considered. The use of the method of direct laser growing allowed obtaining a three-layer material with qualitative interconnection of layers, as well as decreasing a multistage nature of deformation and thermal operations used when obtaining a three-layer material in earlier works. Additional thermal treatment of a three-layer alloy led to growth of matrix grains up to 100 μm of the vanadium alloy. A uniform distribution of main elements V, Ti, Cr was observed in the transition zone both before and after annealing. A zone of interdiffusion of the metals amounted to 250-350 μm.

Structure and mechanical properties of the three-layer material based on a vanadium alloy and corrosion-resistant steel

2014 ◽  
Vol 2014 (10) ◽  
pp. 793-799 ◽  
Author(s):  
S. A. Nikulin ◽  
A. B. Rozhnov ◽  
T. A. Nechaikina ◽  
S. O. Rogachev ◽  
S. Yu. Zavodchikov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistant Steel ◽  
Vanadium Alloy ◽  
Resistant Steel ◽  
Corrosion Resistant ◽  
Layer Material

Fracture Toughness of Highly Irradiated Pressure Vessel Steels in the Upper Shelf Temperature

2006 ◽  
Author(s):  
Hiroshi Matsuzawa ◽  
Toru Osaki
Keyword(s):  
Fracture Toughness ◽  
Chemical Composition ◽  
Reference Material ◽  
Fast Neutron ◽  
Pressure Vessel ◽  
Charpy Impact ◽  
Pressure Vessels ◽  
Shelf Energy ◽  
Pressure Vessel Steels ◽  
Reactor Pressure

Nine Reactor Pressure Vessel (RPV) Steels and four RPV weld were irradiated up to 1.2 × 1024n/m2 fast neutron fluence (E>1MeV), and their fracture toughness and Charpy impact energy were measured. As chemical compositions, such as Cu, are known to affect the fracture toughness reduction due to neutron exposure, the above steels were fabricated by changing chemical composition widely to cover the chemical composition of the RPV materials of the operating Japanese nuclear power plants. 2.7 mm thick compact specimens were used to measure the upper shelf fracture toughness of highly irradiated materials, and their Charpy upper shelf energy was also measured. By correlating Charpy upper shelf energy to fracture toughness, the upper shelf fracture toughness evaluation formulae for highly irradiated reactor pressure vessel steels were developed. Both compact and V-notched Charpy impact specimens were irradiated in a test reactor. The fast neutron flux above 1MeV was about 5 × 1016n/(m2s). Charpy impact specimens made of Japanese PWR reference material containing 0.09w% Cu were irradiated simultaneously. The upper shelf energy of the reference material up to the medium fluence level showed little difference in the reduction of upper shelf energy to that which had been in the operating plant and which was irradiated to the same fluence. The developed correlation formulae have been adopted in the Japan Electric Association Code as new formulae to predict the fracture toughness in the upper shelf region of reactor pressure vessels. They will be applied to time limited ageing analysis of low upper shelf reactor pressure vessels in Japan, on a concrete technical basis in very high fluence regions.

Effect of Chemical Composition and Microstructure Parameters on Carbon and Low-Alloy Steel Corrosion Resistance

Metallurgist ◽  
2018 ◽  
Vol 61 (9-10) ◽  
pp. 770-776
Author(s):  
I. G. Rodionova ◽  
M. V. Feoktistova ◽  
O. N. Baklanova ◽  
A. V. Amezhnov ◽  
D. L. D’yakonov
Keyword(s):  
Corrosion Resistance ◽  
Chemical Composition ◽  
Alloy Steel ◽  
Steel Corrosion ◽  
Low Alloy Steel ◽  
Microstructure Parameters ◽  
Steel Corrosion Resistance
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