GTAW Welded Inconel 625 Alloy Fuel Cladding for the Canadian SCWR: Microstructure and Mechanical Property Characterization

2020 ◽  
Author(s):  
German Cota-Sanchez ◽  
Lin Xiao
Keyword(s):  
Mechanical Properties ◽  
Grain Growth ◽  
Dendritic Structure ◽  
Base Material ◽  
Mechanical Tests ◽  
Nuclear Industry ◽  
Reactor Fuel ◽  
Inconel 625 ◽  
Fuel Cladding ◽  
Inconel 625 Alloy

Abstract Inconel 625 is considered one of the candidate materials for reactor fuel cladding in the Canadian supercritical water reactor (SCWR) design. Gas tungsten arc welding (GTAW) is being evaluated as a joining technique for SCWR fuel cladding since this method is widely used to join components in the power and nuclear industry. During the GTAW process, the welding thermal cycle produces different types of microstructures in both the heat-affected zone (HAZ) and fusion zone (FZ) that affect the material's mechanical properties. A series of welding experiments at various weld conditions were performed using an automatic GTAW orbital process on Inconel 625 alloy tubing. Simple analytical heat conduction and grain growth models were developed to predict weld temperature profiles and metallurgical transformations. Weld characterization included mechanical tests, optical microscopy, scanning electron microscopy - energy dispersive spectroscopy (SEM-EDS) elemental analysis, and microhardness measurements. Weld microstructural characterization revealed that a characteristic dendritic structure was formed in the FZ, while the HAZ exhibited larger equiaxed grains than those found in the base material. SEM-EDS analysis showed no distinct alloying element segregation in both the HAZ and FZ. Welds produced with heat inputs of about 3.00 kJ/cm3 presented similar mechanical properties as those observed in the base material. In these welds, grain growth was homogenously minimized in the FZ. It is concluded that the effective welding heat input control can optimize the weld microstructure and the weld mechanical properties in Inconel 625 tubing used as Canadian SCWR reactor fuel cladding.

Experimental Program to Monitor the Irradiation Induced Embrittlement of the French Reactor Pressure Vessel Steels

2004 ◽  
Author(s):  
Guillaume Chas ◽  
Nathalie Rupa ◽  
Josseline Bourgoin ◽  
Astrid Hotellier ◽  
Se´bastien Saillet
Keyword(s):  
Mechanical Properties ◽  
Pressure Vessel ◽  
Mechanical Tests ◽  
Nuclear Industry ◽  
Experimental Program ◽  
Surveillance Program ◽  
Base Metals ◽  
Vessel Steel ◽  
Pressure Vessel Steels ◽  
Reactor Pressure

By monitoring the irradiation-induced embrittlement of materials, the Pressure Vessel Surveillance Program (PVSP) contributes to the RPV integrity and lifetime assessments. This program is implemented on each PWR Unit in France; it is mainly based on Charpy tests, which are widely used in the nuclear industry to characterize the mechanical properties of the materials. Moreover, toughness tests are also carried out to check the conservatism of the PVSP methodology. This paper first describes the procedure followed for the Pressure Vessel Surveillance Program. It presents the irradiation capsules: the samples materials (low alloy Mn, Ni, Mo vessel steel including base metals, heat affected zones, welds and a reference material) and the mechanical tests performed. Then it draws up a synthesis of the analysis of about 180 capsules removed from the reactors at fluence levels up to 7.1019 n/cm2 (E > 1 MeV). This database gathers the results of more than 10,000 Charpy tests and 250 toughness tests. The experimental results confirm the conservatism of the Code-based methodology applied to the toughness assessment.

Experimental Study on the Relationship of Discharge Parameters with Crack Arrest Effects in Inconel 625 Alloy by Electropulsing Treatment

2017 ◽  
Vol 909 ◽  
pp. 73-79
Author(s):  
Jing Yu ◽  
Yan Chuan Liu
Keyword(s):  
Mechanical Properties ◽  
Energy Input ◽  
Electric Energy ◽  
Crack Tip ◽  
Crack Arrest ◽  
Inconel 625 ◽  
Inconel 625 Alloy ◽  
Discharge Parameters ◽  
Electropulsing Treatment ◽  
The Relationship

The detour effect and Joule heating of electropulsing is employed on crack arrest. With respect to Inconel 625 alloy, the relationship between discharge parameters and the area of fusion zone, microstructure around the crack tip and mechanical properties are studied. The experimental results indicate that the area of molten hole is directly proportional to the electric energy input. The microstructure ahead of the crack tip is refined and uniform with the increase of electric energy input. The optimum discharge parameter range, which contributes to the improvement of comprehensive mechanical properties, can be obtained.

Laser Metal Deposition Additive Manufacturing of TiC Reinforced Inconel 625 Composites: Influence of the Additive TiC Particle and Its Starting Size

2016 ◽  
Vol 139 (4) ◽  
Author(s):  
Dongdong Gu ◽  
Sainan Cao ◽  
Kaijie Lin
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Central Zone ◽  
Metal Deposition ◽  
Inconel 625 ◽  
Wear Property ◽  
Laser Metal Deposition ◽  
Inconel 625 Alloy ◽  
Tic Particle ◽  
Original Size

In this study, laser metal deposition (LMD) additive manufacturing was used to deposit the pure Inconel 625 alloy and the TiC/Inconel 625 composites with different starting sizes of TiC particles, respectively. The influence of the additive TiC particle and its original size on the constitutional phases, microstructural features, and mechanical properties of the LMD-processed parts was studied. The incorporation of TiC particles significantly changed the prominent texture of Ni–Cr matrix phase from (200) to (100). The bottom and side parts of each deposited track showed mostly the columnar dendrites, while the cellular dendrites were prevailing in the microstructure of the central zone of the deposited track. As the nano-TiC particles were added, more columnar dendrites were observed in the solidified molten pool. The incorporation of nano-TiC particles induced the formation of the significantly refined columnar dendrites with the secondary dendrite arms developed considerably well. With the micro-TiC particles added, the columnar dendrites were relatively coarsened and highly degenerated, with the secondary dendrite growth being entirely suppressed. The cellular dendrites were obviously refined by the additive TiC particles. When the nano-TiC particles were added to reinforce the Inconel 625, the significantly improved microhardness, tensile property, and wear property were obtained without sacrificing the ductility of the composites.

Effect of Brazing and Heat Treatment Cycle on the Mechanical Properties of Base Materials

2015 ◽  
Vol 830-831 ◽  
pp. 310-313
Author(s):  
N. Dileep Kumar ◽  
K. Thomas Tharian ◽  
Aby Isaac ◽  
P.V. Venkitakrishnan
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Grain Growth ◽  
Braze Alloy ◽  
Base Material ◽  
Growth Patterns ◽  
Outer Shell ◽  
Liquid Oxygen ◽  
Gas Generator ◽  
Base Materials

Brazing is extensively used in liquid rocket engines for realizing various subsystems. In the case of cryogenic engines, brazing operation is done to realize the gas generator. Gas Generator is one of the major systems of cryogenic engine. It generates and supplies hot gases required for running turbine of main turbo pump. This uses liquid oxygen and gaseous hydrogen as propellant combination. Combustion chamber of Gas Generator is of double walled construction with the cylindrical outer shell of transition class ICSS-0716-301 austenitic-martensitic stainless steel and inner shell of ICSS-1218 321, aTi stabilized austenitic stainless steel material brazed together with Fe-Ni-Mn type braze alloy at a temperature of 1180°C. This temperature can cause the grain growth and related issues to the base material. Thus the present work focuses on the effect of the brazing/thermal cycle on mechanical properties and microstructure of the base materials in post braze condition. The results obtained on metallurgical/mechanical behavior of the material showed the different grain growth patterns in inner and outer shell materials. This helped in understanding the effect of brazing condition on the changes in mechanical properties of base materials.

scholarly journals The Interface Microstructures and Mechanical Properties of Laser Additive Repaired Inconel 625 Alloy

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4416
Author(s):  
Yiyun Wei ◽  
Guomin Le ◽  
Qingdong Xu ◽  
Lei Yang ◽  
Ruiwen Li ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Tensile Properties ◽  
Dendritic Structure ◽  
Laves Phase ◽  
Inconel 625 ◽  
Second Phase ◽  
Equiaxed Crystal ◽  
Columnar Crystal ◽  
Inconel 625 Alloy ◽  
Deposition Thickness

The microstructure and micro-mechanics around the repaired interface, and the tensile properties of laser additive repaired (LARed) Inconel 625 alloy were investigated. The results showed that the microstructure around the repaired interface was divided into three zones: the substrate zone (SZ), the heat-affected zone (HAZ), and the repaired zone (RZ). The microstructure of the SZ had a typical equiaxed crystal structure, displaying simultaneously precipitated block-shaped MC-type carbides (NbC, TiC), with bimodal sizes of approximately 10 μm and 0.5 μm and an irregularly shaped flocculent Laves phase. Recrystallization occurred in the HAZ, and led to significant grain growth; a portion of the second phase dissolved in the original grain boundaries. In the RZ, there was a columnar crystal structure, and the size increased with increasing deposition thickness. Moreover, the microstructure between the layer interface and layer interior was quite different, presenting an overlapping transition zone (OTZ), in which the dendritic structure coarsened and more Laves phase were precipitated, compared to in the layer interior. The hardness and tensile properties of the LARed samples were equivalent to those of the wrought substrate, which indicates that laser additive repairing (LAR) is a reliable repair solution for damaged and mis-machined components comprising Inconel 625 alloy.

The Microstructure of Weld Overlay Ni-Base Alloy Deposited on Carbon Steel by CMT Method

2015 ◽  
Vol 231 ◽  
pp. 119-124 ◽  
Author(s):  
Monika Solecka ◽  
Paweł Petrzak ◽  
Agnieszka Radziszewska
Keyword(s):  
Carbon Steel ◽  
Base Alloy ◽  
Dendritic Structure ◽  
Inconel 625 ◽  
Cold Metal Transfer ◽  
Inconel 625 Alloy ◽  
Second Phases ◽  
Transfer Method ◽  
Cold Metal ◽  
Weld Overlays

Ni-base alloys, like Inconel 625, exhibit a high temperature corrosion and oxidation resistance. For this reason, these alloys are typically used as a one of the most important coating material and can be applied in a different environments and elements of devices having various applications. In this work, Inconel 625 was deposited onto a carbon steel P235GH by Cold Metal Transfer method. Due to the segregation of Ni, Cr, Nb and Mo elements the Inconel 625 weld overlays cladded on boiler pipes P235GH obtained the dendritic structure, with the formation of a second phases at the end of solidification. The presence of γ (with high dislocation density), the Laves and (Nb,Ti)C phases was revealed by means of TEM examinations. The multipoint EDS analysis confirmed the presence of low Fe concentration in the Inconel 625 alloy coatings. The concentration profiles of Ni, Cr, Mo and Nb performed across the dendritic structure showed segregation of these elements.

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