Very high cycle regime fatigue of thin walled tubes made from austenitic stainless steel

2002 ◽  
Vol 25 (8-9) ◽  
pp. 837-844 ◽  
Author(s):  
J. V. CARSTENSEN ◽  
H. MAYER ◽  
P. BRØNDSTED
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Thin Walled ◽  
Very High

Some aspects of the defect structure in an austenitic stainless steel

1978 ◽  
Vol 36 (1) ◽  
pp. 314-315
Author(s):  
R. Gonzalez ◽  
L. Bru
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Cellular Structures ◽  
Total Strain Amplitude ◽  
Total Deformation ◽  
Density Of Dislocations ◽  
Planar Arrays ◽  
Stacking Fault Tetrahedra ◽  
Distribution Of Dislocations ◽  
Very High

The analysis of stacking fault tetrahedra (SFT) in fatigued metals (1,2) is somewhat complicated, due partly to their relatively low density, but principally to the presence of a very high density of dislocations which hides them. In order to overcome this second difficulty, we have used in this work an austenitic stainless steel that deforms in a planar mode and, as expected, examination of the substructure revealed planar arrays of dislocation dipoles rather than the cellular structures which appear both in single and polycrystals of cyclically deformed copper and silver. This more uniform distribution of dislocations allows a better identification of the SFT.The samples were fatigue deformed at the constant total strain amplitude Δε = 0.025 for 5 cycles at three temperatures: 85, 293 and 773 K. One of the samples was tensile strained with a total deformation of 3.5%.

Quality Management during Manufacturing of High Tempertaure Thin Walled Austenitic Stainless Steel Sodium Tanks of Prototype Fast Breeder Reactor

2013 ◽  
Vol 794 ◽  
pp. 507-513
Author(s):  
R.G. Rangasamy ◽  
Prabhat Kumar
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Austenitic Stainless Steel ◽  
Quality Management ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Heat Removal ◽  
Fast Breeder Reactor ◽  
Decay Heat ◽  
Thin Walled

Austenitic stainless steels are the major material of construction for the fast breeder reactors in view of their adequate high temperature mechanical properties, compatibility with liquid sodium coolant, good weldability, availability of design data and above all the fairly vast and satisfactory experience in the use of these steels for high temperature service. All the Nuclear Steam Supply System (NSSS) components of FBR are thin walled structure and require manufacture to very close tolerances under nuclear clean conditions. As a result of high temperature operation and thin wall construction, the acceptance criteria are stringent as compared to ASME Section III. The material of construction is Austenitic stainless steel 316 LN and 304 LN with controlled Chemistry and calls for additional tests and requirements as compared to ASTM standards. Prototype Fast Breeder Reactor (PFBR) is sodium cooled, pool type, 500 MWe reactor which is at advanced stage of construction at Kalpakkam, Tamilnadu, India. In PFBR, the normal heat transport is mainly through two secondary loops and in their absence; the decay heat removal is through four passive and independent safety grade decay heat removal loops (SGDHR). The secondary sodium circuit and the SGHDR circuit consist of sodium tanks for various applications such as storage, transfer, pressure mitigation and to take care of volumetric expansion. The sodium tanks are thin walled cylindrical vertical vessels with predominantly torispherical dished heads at the top and bottom. These tanks are provided with pull-out nozzles which were successfully made by cold forming. Surface thermocouples and heaters, wire type leak detectors are provided on these tanks. These tanks are insulated with bonded mineral wool and with aluminum cladding. All the butt welds in pressure parts were subjected to 100% Radiographic examination. These tanks were subjected to hydrotest, pneumatic test and helium leak test under vacuum. The principal material of construction being stainless steel for the sodium tanks shall be handled with care following best engineering practices coupled with stringent QA requirements to avoid stress corrosion cracking in the highly brackish environment. Intergranular stress corrosion cracking and hot cracking are additional factors to be addressed for the welding of stainless steel components. Pickling and passivation, Testing with chemistry controlled demineralised water are salient steps in manufacturing. Corrosion protection and preservation during fabrication, erection and post erection is a mandatory stipulation in the QA programme. Enhanced reliability of welded components can be achieved mainly through quality control and quality assurance procedures in addition to design and metallurgy. The diverse and redundant inspections in terms of both operator and technique are required for components where zero failure is desired & claimed. This paper highlights the step by step quality management methodologies adopted during the manufacturing of high temperature thin walled austenitic stainless steel sodium tanks of PFBR.

Welding and Fabrication of Stainless Steel Equipment for 500MWe Prototype Fast Breeder Reactor

2013 ◽  
Vol 794 ◽  
pp. 305-315
Author(s):  
Prabhat Kumar
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Arc Welding ◽  
Welding Distortion ◽  
Fast Breeder Reactor ◽  
Mandatory Requirement ◽  
Main Vessel ◽  
Grid Plate ◽  
Thin Walled ◽  
Inner Vessel

Austenitic stainless steel is the major structural material for the primary and secondary sodium systems (except for the steam generators) for the currently operating and planned fast reactors all over the world. The boundaries of sodium systems of Prototype Fast Breeder Reactor (PFBR) is designed so as to have an extremely low probability of leakage, rapidly propagating failure and gross rupture under the static & dynamic loads expected during various operating conditions.The degradation of material properties (e.g. effect of sodium, temperature and irradiation), transients, residual stresses, flaw size etc. are the important considerations, which shall be taken into account. The principal material of construction for PFBR is austenitic stainless steel of grade 316LN/304LN. The scope of welding and fabrication of PFBR components is too large due to versatile types of systems with varieties of components with complex constructional features. High operating temperature of various systems causing high stresses are to be minimized by designing thin walled structure. Most of the Nuclear Steam Supply System (NSSS) components are thin walled and require manufacturing in separate nuclear clean hall conditions to assure the quality.The welding with stringent tolerances along with high distortion in stainless steels due to high thermal expansion and low thermal conductivity makes the fabrication extremely challenging.The welding standards and acceptance criteria of PFBR equipment is stringent compared to other industrial specification. Manufacture of over dimensional components (diameter greater than 12m and thickness upto 40mm) such as MainVessel, Safety Vessel, Inner Vessel involves die pressing of large size dished end & conical petals. The solution annealing of cold worked petals is a mandatory requirement if strain exceeds 10%. Innovative welding techniques and many trials were conducted on mock up for establishing the process parameters. The forming techniques, bending methods and welding procedures were qualified with stringent non-destructive and destructive examinations and testing before taking up the actual job. Thermal Baffle has two large concentric cylindrical shells, inner and outer shells of about 12.4m diameter and fabrication is a challenging task. PFBR also involves dissimilar joint welding between carbon steel (A48P2) and austenitic stainless steel (316LN) at integration location of roof slab & main vessel. This welding is carried out by combination of Gas Tungsten Arc Welding (GTAW) & Shielded Metal Arc Welding (SMAW) processes using ER 309L & E 309-16 welding consumables with controlled heat input to minimize the dilution of carbon & distortion. The weld between primary pipe & grid plate cannot be accessed for in-service inspection and therefore requires extra-ordinary skilled welders. Space constraints & lack of accessibility makes the welding & inspection challenging. This paper highlights the welding and fabrication aspects of few major, over dimensional and critical equipment of 500MWe Prototype Fast Breeder Reactor. Keywords: Stainless Steel, Main Vessel, Safety Vessel, Inner Vessel, Grid Plate, PFBR, SS welding, distortion.

AVESTA POLARIT 724L

Alloy Digest ◽  
2001 ◽  
Vol 50 (10) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Physical Properties ◽  
High Resistance ◽  
Intergranular Corrosion ◽  
Heat Treating ◽  
Urea Production ◽  
Very High

Abstract Avesta Polarit 724L is a 17-13-2.5L special austenitic stainless steel developed for use in urea production, especially hot carbamate solutions. The alloy also has a very high resistance to intergranular corrosion. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-501. Producer or source: AvestaPolarit AB. Originally published as Avesta 17-13-2.5L, January 1989, revised October 2001.

NAS 354N

Alloy Digest ◽  
2010 ◽  
Vol 59 (6) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Crevice Corrosion ◽  
Nickel Content ◽  
Heat Treating ◽  
Good Resistance ◽  
Resistance To Stress ◽  
Super Austenitic Stainless Steel ◽  
Very High

Abstract NAS 354N is a super austenitic stainless steel with very high molybdenum for pitting and crevice corrosion resistance and high enough nickel content for good resistance to stress-corrosion cracking. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-1066. Producer or source: Nippon Yakin Kogyo Company Ltd.

SUMITOMO SM2535-125

Alloy Digest ◽  
2017 ◽  
Vol 66 (7) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Strength ◽  
Heat Treating ◽  
Sour Service ◽  
Very High

Abstract Sumitomo SM2535 is a very high strength austenitic stainless steel for use in oil country tubular goods as a material suitable for severe sour service. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming and heat treating. Filing Code: SS-1268. Producer or source: Nippon Steel and Sumitomo Metal Corporation.

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