Evaluation of Irradiation Embrittlement of the Weld Metals in the Chinese RPV

2020 ◽  
Author(s):  
Yupeng Cao ◽  
Yinbiao He ◽  
Yifeng Huang ◽  
Binxi Wang ◽  
Yan Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Nuclear Power ◽  
Degradation Mechanism ◽  
Base Material ◽  
Charpy Impact ◽  
Tensile Tests ◽  
Irradiation Damage ◽  
Limiting Factor ◽  
Irradiation Embrittlement ◽  
Weld Metals

Abstract Reactor pressure vessel (RPV) operates under high temperatures and pressures and is exposed to relatively high neutron radiation. RPV is considered to be irreplaceable, which is the most limiting factor for the lifetime of a nuclear power plant. As the most severe ageing degradation mechanism in RPV materials, irradiation embrittlement is a major issue affecting the integrity through the service life of a RPV. Our previous paper (ASME PVP2019-93615[1]) introduced our project for assessment of irradiation embrittlement of the materials for the Chinese RPVs to verify the 60-year design life, in which the specimens made of the RPV base material manufactured in China, the SA-508 Gr.3 Cl.1 forging, and the different types of weld metals were irradiated in the high fluence engineering test reactor (HFETR). The paper analyzed extent irradiation damage of the forging in terms of mechanical properties. As another part of the project, this paper concentrates on the evaluation of the weld metals in the same project. Tensile tests, Charpy impact tests and fracture toughness tests by master curve approach were carried out for the three types of weld metals subjected to different irradiation fluences (2.6E19n/cm2, 8.9E19n/cm2). Comparison of the mechanical properties of the irradiated and the unirradiated materials is made. The irradiation resistance of the weld metals in our project is also compared with the data in the literatures.

Evaluation of Irradiation Embrittlement of the Chinese RPV Steels

2019 ◽  
Author(s):  
Yupeng Cao ◽  
Yinbiao He ◽  
Binxi Wang ◽  
Yifeng Huang ◽  
Hui Li ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Master Curve ◽  
Charpy Impact ◽  
Tensile Tests ◽  
Limiting Factor ◽  
High Fluence ◽  
Irradiation Embrittlement ◽  
Test Reactor ◽  
Reactor Pressure ◽  
Irradiation Resistance

Abstract Reactor pressure vessel (RPV) is considered to be irreplaceable, which is the most limiting factor for the lifetime of a nuclear power plant. This paper aims to introduce our project for the evaluation of the irradiation embrittlement for the Chinese RPV forging. The forging manufactured in China was irradiated in the high fluence engineering test reactor. Tensile tests, Charpy impact tests and fracture toughness tests in terms of master curve T0 were carried out for the material subjected to different irradiation fluences. Comparison of the mechanical properties of the irradiated materials and the materials without irradiation is made. The irradiation resistance of the materials in our project is also compared with the data for the irradiated RPV steels in the literatures.

Mechanical Properties and Microstructure of LR Grade a Thick Plate Welded by Double Side Gas Metal Arc Welding

2016 ◽  
Vol 851 ◽  
pp. 168-172
Author(s):  
Yustiasih Purwaningrum ◽  
Triyono ◽  
Tegar Rileh Argihono ◽  
Ryan Sutrisno
Keyword(s):  
Mechanical Properties ◽  
Gas Flow ◽  
Gas Metal Arc Welding ◽  
Charpy Impact ◽  
Hardness Test ◽  
Charpy Impact Test ◽  
Optical Microscope ◽  
Steel Plates ◽  
Weld Metals ◽  
Metal Arc Welding

Mechanical and microstructure of double side weld with various angle groove was studied in this research. LR Gr A steel plates (12 mm thickness) were welded using GMAW with corresponding 180 A, 23 V, and 20 l/min respectively with current, voltage, and gas flow. Shielding gas and filler metals used are argon and ER 70S-6. The angle groove that used were 20⁰, 40⁰ and 60⁰. The measured of mechanical properties with regard to hardness, toughness and strength using, Vickers hardness test, Charpy impact test and tensile test respectively The microstructure examined with optical microscope. The results show that the highest hardness values found in welds with groove angle 40ͦ. The transition temperatures of weld metals are at temperatures between -20°C to 0°C. Weld metals with all variations of the groove angle has a value of less than 0.1 mmpy. Microstructure of base metals and HAZ were ferrite and pearlite. While the microstructure of weld metals are accicular ferrite, grain boundary ferrite and Widmanstatten ferrite.

Yb:YAG Disc Laser Welding of Austenitic Stainless Steel Without Filler Material

2009 ◽  
Vol 410-411 ◽  
pp. 87-96 ◽  
Author(s):  
Markku Keskitalo ◽  
Kari Mäntyjärvi
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Cross Sections ◽  
Base Material ◽  
Tensile Tests ◽  
Solidification Cracking ◽  
Filler Material ◽  
Test Material ◽  
Butt Weld

The laser weldability of austenitic stainless steel (ASS) is good because of the material’s high absorptivity and favourable microstructure. There can be a slight possibility of solidification cracking at high welding speeds and low Crekv/Niekv ratios. Test welds were welded with a Yb:YAG disc laser. The test material was 3.2 mm EN 1.4404 2H C700 type stainless steel plate which was work hardened by cold rolling. The test materials were welded with different heat inputs ranging from 0.024 kJ/mm to 0.12 kJ/mm and with 300 mm and 200 mm focal lengths. The weld seams were square-groove welded as butt weld without filler material. The edges of the groove were made by mechanical or laser cutting. The hardness profiles from cross-sections of the welds were measured with a Vickers microhardness tester using 200 g weight. The mechanical properties were tested with tensile tests. The welds were classified with radiographic verification by an accredited laboratory. A number of the welds were fatigue tested with a bending fatigue tester. The mechanical properties (Rp 0.2%, Rm) of the laser welds were almost the same as in the base material except at the highest heat input. In the radiographic classification, the welds which were welded to the laser-cut edge were classified as class B (accepted). The other welds were classified as class D or C (rejected). The main reasons for the rejection of welds made on mechanically cut edges were lack of penetration or undercut of the weld. A problem with mechanically cut edges, and hence the welds, is that they can be non-square and bent edge. Fatigue tests and tensile tests gave no evidence of solidification cracking in the microstructure of the solidified parts of the welds.

Effect of Neutron Irradiation on the Mechanical Properties of an A508 CL2 and 15Kh2NMFA Irradiated in the NOMAD_3 Rig in the BR2 Cooling Water

2021 ◽  
Author(s):  
Inge Uytdenhouwen ◽  
Rachid Chaouadi
Keyword(s):  
Neutron Irradiation ◽  
Nuclear Reactor ◽  
Cooling Water ◽  
Charpy Impact ◽  
Tensile Tests ◽  
Significant Loss ◽  
Irradiation Temperature ◽  
Irradiation Damage ◽  
Transition Curves ◽  
Reactor Pressure

Abstract The typical operating temperatures of a nuclear reactor pressure vessel in a PWR are between 290°C and 300°C. However, many BWRs and some PWRs operate at slightly lower temperatures down to 260°C. Most of the literature and neutron irradiation damage is therefore focused on those irradiation temperatures. It is well-known that the lower the irradiation temperature, the more neutron irradiation damage occurs, because no appreciable annealing happens below approximately 230°C. The NOMAD_3 irradiation consisted in total of 24 Charpy sized samples from an A508 Cl.2 forging and a 15Kh2NMFA material. They were irradiated to three various fluences between 1.55 and 7.90 × 1019 n/cm2 (E > 1MeV) at approximately 100°C. The hardening of the A508 Cl.2 was between 260 and 400 MPa which was much higher than the NOMAD_0 properties which were irradiated at approximately 280°C. The tensile tests of irradiated materials are all characterized by a significant loss of work hardening capacity leading to plastic flow localization promptly after the yield strength is reached. This affects also the shape of the Charpy impact transition curves. The radiation embrittlement derived from Charpy impact tests, ΔT41J, is up to 156°C for the highest fluence. For this irradiation, the embrittlement to hardening ratio was also around 0.43 +/−0.2°C/MPa as it was found in the previous campaign NOMAD_0. This paper discusses the tensile, hardness and impact properties of the NOMAD_3 irradiation campaign. It is compared to the NOMAD_0 with respect to effect of irradiation temperature and annealing recovery.

Mechanical Properties and Forming Behavior of a Type 9%Cr Steel Containing 2%W

2010 ◽  
Vol 638-642 ◽  
pp. 3128-3133 ◽  
Author(s):  
Felix Peñalba ◽  
Xabier Gómez ◽  
R. Allende ◽  
Manuel Carsí ◽  
Oscar A. Ruano
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Charpy Impact ◽  
Tensile Tests ◽  
Ferritic Steels ◽  
Strain Rates ◽  
Ductile Brittle Transition Temperature ◽  
Stability Maps ◽  
Hot Torsion ◽  
Strength And Ductility

The possibilities to improve the properties of steels for tubes exposed at high temperatures are explored. The mechanical properties and forming behavior of an experimental casting of type 9Cr-ferritic steels, P92, containing 2%W, are studied. The hardenability was determined by means of continuous cooling diagrams associated with hardness measurements and microstructure observations. Tensile tests from room temperature to 650°C were carried out to determine the variation of the strength and ductility in this temperature range. In addition, Charpy impact tests were conducted to characterize the toughness of the steel and the ductile-brittle transition temperature. Finally, hot torsion tests at various temperatures and strain rates were carried out and the generalized stresses and strains to rupture for each test are determined. With these data forming stability maps were generated to characterize the best forming conditions.

Assessment of Weld Heat-Affected Zones in a Reactor Vessel Material

1978 ◽  
Vol 100 (3) ◽  
pp. 267-271 ◽  
Author(s):  
T. U. Marston ◽  
W. Server
Keyword(s):  
Mechanical Properties ◽  
Base Material ◽  
Charpy Impact ◽  
Dynamic Fracture Toughness ◽  
Reactor Vessel ◽  
Heavy Section ◽  
Vessel Material ◽  
Submerged Arc ◽  
Weld Heat

The mechanical properties of weld heat-affected zones (HAZ’s) associated with the heavy section, nuclear quality weldments are evaluated and found to be superior to those of the parent base material. The nil ductility transition temperature (NDTT), Charpy impact and static and dynamic fracture toughness properties of a HAZ associated with a submerged arc weld and one associated with a manual metal arc weld are directly compared with those of the parent base material. It is concluded that the stigma normally associated with HAZ is not justified for this grade and quality of material and weld procedure.

Effect of Tool Parameters on Mechanical Properties of Friction Stir Welded Aluminum Alloy

2015 ◽  
Vol 786 ◽  
pp. 111-115 ◽  
Author(s):  
Srinivasa Rao Pedapati ◽  
G. Vimalan ◽  
Mokhtar Awang ◽  
A.M.A. Rani
Keyword(s):  
Mechanical Properties ◽  
Rotational Speed ◽  
Base Material ◽  
Hardness Test ◽  
Tensile Tests ◽  
Tool Geometry ◽  
Welding Parameters ◽  
Material Strength ◽  
Friction Stir ◽  
Tool Profiles

The mechanical properties of weld joints in Friction Stir Welding (FSW) are influenced by the welding parameters such as rotational speed, tool geometry and welding speed. In the present study, three different tool profiles have been used to weld the joints with three different rotational speed and two welding speeds. Full factorial experiments have been conducted using DoE. The mechanical properties of weld joint were evaluated by means of tensile tests and hardness test at room temperature. The experiment result shows that the average highest number of hardness was 40.06 HRB with square tool at a rotational speed of 2000rpm while lowest hardness was 30.84 HRB with cylindrical threaded tool at rotational speed of 1800rpm. The maximum tensile strength of the joint obtained is 265 M Pa which is close to base material strength. It is observed from experimental results that joints made by square tool yield more strength compared to other tool profiles.

The effect of metal transfer modes on mechanical properties of 3CR12 stainless steel

2020 ◽  
Vol 44 (2) ◽  
pp. 256-262
Author(s):  
Daniel M. Madyira ◽  
Abdullah Kaymakci ◽  
Ntokozo Nkwanyana
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Grain Growth ◽  
Charpy Impact ◽  
Metal Transfer ◽  
Test Material ◽  
Limiting Factor ◽  
Air Cooling ◽  
Butt Welding ◽  
Martensitic Microstructure

The effect of metal transfer modes on mechanical properties of welded 3CR12 stainless steel was investigated. This was achieved by butt welding 10 mm thick plates of 3CR12. The effect of the metal transfer modes on the microstructure and the mechanical properties of the 3CR12 steel was then investigated as it was hypothesized that the change in welding positions will affect the transfer modes partly because of gravity. The microscopic examination revealed that the substrate was characterized by dual phase microstructure. Using the spectroscopic examination results, the ferritic factor calculation had shown that the microstructure was expected to be ferritic–martensitic during air cooling process. The tensile strength and Charpy impact energy were measured to be 498 MPa and 102 J, respectively. The heat input in the material was observed to be greater than 1 kJ/mm, which is the limiting factor for grain growth. Grain growths were observed in the heat affected zone of the welded materials. Ferritic–martensitic microstructure was observed in the microstructure. The grain growth altered the mechanical properties of the test material. Globular down hand had higher mechanical properties than spray down hand. Globular vertical up had better mechanical properties than globular vertical down.

scholarly journals The Influence of Multiple Pass Submerged Friction Stir Processing on the Microstructure and Mechanical Properties of the FSWed AA6082-AA8011 Joints

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1429
Author(s):  
Sipokazi Mabuwa ◽  
Velaphi Msomi
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Processing ◽  
Microstructural Analysis ◽  
Base Material ◽  
Tensile Tests ◽  
Friction Stir ◽  
Grain Sizes ◽  
Microstructure And Mechanical Properties ◽  
Multiple Pass ◽  
The One

The AA6082–AA8011 friction stir-welded joints were subjected to submerged multiple pass friction stir processing to evaluate the microstructure and mechanical properties of the joints. A maximum of four submerged friction stir processed passes were used in this study. All the specimens were extracted from three different joint positions (start, middle and end). The tests conducted included microstructural analysis, tensile tests, hardness and fracture surface morphology of the post-tensile specimens, were performed using a scanning electron microscope (SEM). There was no particular trend in the microstructure and mechanical properties when looking at the specimen positioning in all the passes. The minimum mean grain sizes were refined from 3.54 to 1.49 µm and the standard deviation from 5.43 to 1.87 µm. The ultimate tensile strength was improved from 84.96 to 94.77 MPa. The four-pass SFSPed specimens were found to have more ductile properties compared to the one-pass SFSPed one. The hardness of the stir zones in all the passes was found to be higher compared to the AA8011 base material but lower than the AA6082 one. The maximum stir zone hardness of 75 HV was observed on the one-pass SFSP joints.

Effect of Different Heat Treatments on Microstructure and Mechanical Properties of Steel Containing Ni of 9% Base and Weld Metals

2013 ◽  
Vol 275-277 ◽  
pp. 2148-2155
Author(s):  
Min Zhang ◽  
Qiao Ling Chu ◽  
Ji Hong Li
Keyword(s):  
Mechanical Properties ◽  
Comparative Study ◽  
Arc Welding ◽  
Tensile Tests ◽  
Heat Treatments ◽  
Shielded Metal Arc Welding ◽  
Weld Metals ◽  
Microstructure And Mechanical Properties ◽  
Metal Arc Welding ◽  
Quenching And Tempering

An comparative study was made of microstructure and mechanical properties of steel constaining Ni of 9% in different heat treatments. Shielded metal arc welding (SMAW) was employed as jointing technique. Double normalizing and tempering (NNT) and quenching, intercritical quenching and tempering (QLT) were applied as the heat treatments. Instrumented impact and tensile tests were performed between 20°C and 196°C. The results show that both the microstructure and mechanical properties of base and weld metals in QLT solution turn out to be the optimal.

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