Coaxing Effect in Stainless Steels and High-Strength Steels

2007 ◽  
Vol 345-346 ◽  
pp. 235-238 ◽  
Author(s):  
Masaki Nakajima ◽  
Jae Woong Jung ◽  
Yoshihiko Uematsu ◽  
Keiro Tokaji
Keyword(s):  
Stainless Steels ◽  
Fatigue Testing ◽  
High Strength Steels ◽  
Austenitic Stainless Steels ◽  
High Strength ◽  
Hardness Test ◽  
Fatigue Tests ◽  
Diffraction Measurement ◽  
Strain Induced Martensite ◽  
Rotating Bending Fatigue

The effects of prestrain and strength level on the coaxing behavior were studied in austenitic stainless steels and high strength steels, respectively. The materials used were austenitic stainless steels, SUS304 and SUS316, and high strength steels, SCM435, SNCM439 and SUJ2. Stress incremental fatigue tests were performed using cantilever-type rotating bending fatigue testing machines. It was found that the steels except for SUJ2 showed a marked coaxing effect. Non-propagating cracks were not detected in all the steels examined. Based on hardness test, X-ray diffraction measurement and EBSD analysis, it was indicated that the coaxing effect occurred due to work hardening and strain-induced martensite transformation in austenitic stainless steels and to strain-aging in high strength steels.

Strategy of Considering Microstructural Effect on Weld Residual Stress Analysis

2004 ◽  
Author(s):  
Masahito Mochizuki ◽  
Masao Toyoda
Keyword(s):  
Residual Stress ◽  
Thermal Stress ◽  
Stress Analysis ◽  
Stainless Steels ◽  
High Strength Steels ◽  
Austenitic Stainless Steels ◽  
High Strength ◽  
Weld Residual Stress ◽  
Residual Stress Analysis ◽  
Microstructural Effect

Thermal distortion and residual stress are essentially generated by welding and it is well known that they affect the performance of welded structures such as brittle fracture, fatigue, buckling deformation, and stress-corrosion cracking. Welding distortions and residual stresses can be possible controlled and reduced by using some countermeasures. Not only thermal stress behavior but also prediction of microstructural phase during weld heat cycles are very important. High strength steels or martensitic stainless steels are used in a lot of power plant components, and the effect of phase transformation on mechanical behavior during welding in these steels becomes much larger than that of mild steels and austenitic stainless steels. Simultaneous simulation between thermal stress and microstructure during welding should be necessary in a precise evaluation. Analytical method and several applications to actual components are introduced in order to emphasize the effect considering microstructure on weld residual stress analysis.

Strategy of Considering Microstructure Effect on Weld Residual Stress Analysis

2006 ◽  
Vol 129 (4) ◽  
pp. 619-629 ◽  
Author(s):  
Masahito Mochizuki ◽  
Masao Toyoda
Keyword(s):  
Residual Stress ◽  
Thermal Stress ◽  
Stress Analysis ◽  
Stainless Steels ◽  
High Strength Steels ◽  
Austenitic Stainless Steels ◽  
High Strength ◽  
Weld Residual Stress ◽  
Residual Stress Analysis ◽  
Microstructure Effect

Welding generates thermal distortion and residual stress, and it is well known that they affect the performance of welded structures by contributing to brittle fracture, fatigue, buckling deformation, and stress-corrosion cracking. Welding distortions and residual stresses can possibly be controlled and reduced by using countermeasures. Not only thermal stress behavior but also the prediction of the microstructural phase during welding heat cycles is very important. High-strength steels or martensitic stainless steels are used in many power plant components, and the effect of phase transformation on the mechanical behavior during welding of these steels becomes much larger than that of mild steels and austenitic stainless steels. Simultaneous simulations of the thermal stress and microstructure during welding are necessary for a precise evaluation. In this paper, an analytical method and several applications using actual components are introduced in order to emphasize the effect of the microstructure on the weld residual stress analysis.

On the Machinability of Powder Metallurgy Austenitic Stainless Steels

1988 ◽  
Vol 110 (4) ◽  
pp. 339-343 ◽  
Author(s):  
J. S. Agapiou ◽  
G. W. Halldin ◽  
M. F. DeVries
Keyword(s):  
Powder Metallurgy ◽  
Stainless Steels ◽  
Single Phase ◽  
High Strength Steels ◽  
Austenitic Stainless Steels ◽  
High Strength ◽  
Technical Literature ◽  
Bulk Properties ◽  
Point Temperature ◽  
Drill Point

Powder Metallurgy (P/M) materials, especially those made of high strength steels, are often reported in the technical literature to have poor machinability when compared to their wrought or cast counterparts. In order to characterize the machinability of single phase P/M materials and to identify the influence of porosity on that behavior, the machinability of P/M 304L austenitic stainless steel was evaluated as a function of porosity, in the range of 64 to 90 percent of theoretical density. Machinability was defined in terms of the average drill point temperature. It was found that the drill temperature increased with porosity to a point. Further increases in porosity produced decreasing levels of average drill point temperature. The nonlinear machinability response was attributed to the offsetting contributions of the thermal conductivity, the work-hardening, and the bulk properties of the P/M material.

Strain-induced martensite effects on transgranular carbide precipitation in type 304 stainless steels

1991 ◽  
Vol 49 ◽  
pp. 604-605
Author(s):  
A.H. Advani ◽  
L.E. Murr ◽  
D. Matlock
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Stress Corrosion Cracking ◽  
Stainless Steels ◽  
Deformation Twin ◽  
Austenitic Stainless Steels ◽  
Carbide Precipitation ◽  
Strain Induced Martensite ◽  
Type 304

Thermomechanically induced strain is a key variable producing accelerated carbide precipitation, sensitization and stress corrosion cracking in austenitic stainless steels (SS). Recent work has indicated that higher levels of strain (above 20%) also produce transgranular (TG) carbide precipitation and corrosion simultaneous with the grain boundary phenomenon in 316 SS. Transgranular precipitates were noted to form primarily on deformation twin-fault planes and their intersections in 316 SS.Briant has indicated that TG precipitation in 316 SS is significantly different from 304 SS due to the formation of strain-induced martensite on 304 SS, though an understanding of the role of martensite on the process has not been developed. This study is concerned with evaluating the effects of strain and strain-induced martensite on TG carbide precipitation in 304 SS. The study was performed on samples of a 0.051%C-304 SS deformed to 33% followed by heat treatment at 670°C for 1 h.

AVESTA SHEFFIELD SAF 2507

Alloy Digest ◽  
1996 ◽  
Vol 45 (9) ◽  
Keyword(s):  
High Resistance ◽  
Stainless Steels ◽  
Coefficient Of Thermal Expansion ◽  
Austenitic Stainless Steels ◽  
High Strength ◽  
Heat Treating ◽  
General Corrosion ◽  
Temperature Performance ◽  
Chloride Stress Corrosion Cracking ◽  
Very High

Abstract Avesta Sheffield SAF 2507 is an austenitic/ferritic duplex stainless steel with very high strength. The alloy has a lower coefficient of thermal expansion and a higher thermal conductivity than austenitic stainless steels. The alloy has a high resistance to pitting, crevice, and general corrosion; it has a very high resistance to chloride stress-corrosion cracking. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-652. Producer or source: Avesta Sheffield Inc.

Fatigue and Burst Analysis of Hy-140(T) Steel Pressure Vessels

1970 ◽  
Vol 92 (1) ◽  
pp. 11-16 ◽  
Author(s):  
J. M. Barsom ◽  
S. T. Rolfe
Keyword(s):  
Yield Strength ◽  
Pressure Vessel ◽  
Low Cycle Fatigue ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Tests ◽  
Pressure Vessels ◽  
High Yield ◽  
Corrosion Properties ◽  
Burst Analysis

Increasing use of high-strength steels in pressure-vessel design has resulted from emphasis on decreasing the weight of pressure vessels for certain applications. To demonstrate the suitability of a 140-ksi yield strength steel for use in unwelded pressure vessels, HY-140(T)—a quenched and tempered 5Ni-Cr-Mo-V steel—was fabricated and subjected to various burst and fatigue tests, as well as to various laboratory tests. In general, results of the investigation indicated very good tensile, Charpy, Nil Ductility Transition Temperature (NDT), low-cycle fatigue, and stress-corrosion properties of HY-140(T) steels, as well as very good burst tests results, in comparison with existing high-yield strength pressure-vessel steels. The results also indicate that the HY-140(T) steel should be an excellent material for its originally designed purpose, Naval hull applications.

scholarly journals Effect of Neutron Irradiation on the Mechanical Properties, Swelling and Creep of Austenitic Stainless Steels

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2622
Author(s):  
Malcolm Griffiths
Keyword(s):  
Mechanical Properties ◽  
Stainless Steels ◽  
Dimensional Stability ◽  
Operating Experience ◽  
Austenitic Stainless Steels ◽  
High Strength ◽  
Gas Production ◽  
Rate Theory ◽  
Fast Reactors ◽  
Internal Structures

Austenitic stainless steels are used for core internal structures in sodium-cooled fast reactors (SFRs) and light-water reactors (LWRs) because of their high strength and retained toughness after irradiation (up to 80 dpa in LWRs), unlike ferritic steels that are embrittled at low doses (<1 dpa). For fast reactors, operating temperatures vary from 400 to 550 °C for the internal structures and up to 650 °C for the fuel cladding. The internal structures of the LWRs operate at temperatures between approximately 270 and 320 °C although some parts can be hotter (more than 400 °C) because of localised nuclear heating. The ongoing operability relies on being able to understand and predict how the mechanical properties and dimensional stability change over extended periods of operation. Test reactor irradiations and power reactor operating experience over more than 50 years has resulted in the accumulation of a large amount of data from which one can assess the effects of irradiation on the properties of austenitic stainless steels. The effect of irradiation on the intrinsic mechanical properties (strength, ductility, toughness, etc.) and dimensional stability derived from in- and out-reactor (post-irradiation) measurements and tests will be described and discussed. The main observations will be assessed using radiation damage and gas production models. Rate theory models will be used to show how the microstructural changes during irradiation affect mechanical properties and dimensional stability.

Use of Duplex Stainless Steel in Economic Design of a Pressure Vessel

2006 ◽  
Vol 129 (1) ◽  
pp. 155-161 ◽  
Author(s):  
Milan Veljkovic ◽  
Jonas Gozzi
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Stainless Steels ◽  
Pressure Vessel ◽  
Design Procedure ◽  
High Strength Steels ◽  
High Strength ◽  
Pressure Vessels ◽  
Economic Design ◽  
European Standard

Pressure vessels have been used for a long time in various applications in oil, chemical, nuclear, and power industries. Although high-strength steels have been available in the last three decades, there are still some provisions in design codes that preclude a full exploitation of its properties. This was recognized by the European Equipment Industry and an initiative to improve economy and safe use of high-strength steels in the pressure vessel design was expressed in the evaluation report (Szusdziara, S., and McAllista, S., EPERC Report No. (97)005, Nov. 11, 1997). Duplex stainless steel (DSS) has a mixed structure which consists of ferrite and austenite stainless steels, with austenite between 40% and 60%. The current version of the European standard for unfired pressure vessels EN 13445:2002 contains an innovative design procedure based on Finite Element Analysis (FEA), called Design by Analysis-Direct Route (DBA-DR). According to EN 13445:2002 duplex stainless steels should be designed as a ferritic stainless steels. Such statement seems to penalize the DSS grades for the use in unfired pressure vessels (Bocquet, P., and Hukelmann, F., 2001, EPERC Bulletin, No. 5). The aim of this paper is to present an investigation performed by Luleå University of Technology within the ECOPRESS project (2000-2003) (http://www.ecopress.org), indicating possibilities towards economic design of pressure vessels made of the EN 1.4462, designation according to the European standard EN 10088-1 Stainless steels. The results show that FEA with von Mises yield criterion and isotropic hardening describe the material behaviour with a good agreement compared to tests and that 5% principal strain limit is too low and 12% is more appropriate.

Improvement of Fatigue Behaviour of High Strength Aluminium Alloys by Fluidized Bed Peening (FBP)

2007 ◽  
Vol 344 ◽  
pp. 87-96 ◽  
Author(s):  
M. Barletta ◽  
F. Lambiase ◽  
Vincenzo Tagliaferri
Keyword(s):  
Fatigue Life ◽  
Fluidized Bed ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Maximum Amplitude ◽  
High Strength ◽  
Operational Parameters ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

This paper deals with a definition of a relatively novel technique to improve the fatigue behavior of high strength aluminum alloys, namely, Fluidized Bed Peening (FBP). Fatigue samples made from AA 6082 T6 alloy were chosen according to ASTM regulation about rotating bending fatigue test and, subsequently, treated by varying FBP operational parameters and fatigue testing conditions. First, a full factorial experimental plan was performed to assess the trend of number of cycles to rupture of fatigue samples varying among several experimental levels the factors peening time and maximum amplitude of alternating stress applied to fatigue samples during rotating bending fatigue tests. Second, design of experiment (DOE) technique was used to analyze the influence of FBP operational parameters on fatigue life of AA 6082 T6 alloy. Finally, ruptures of FB treated samples and untreated samples were discussed in order to evaluate the influence of operational parameters on the effectiveness of FBP process and to understand the leading process mechanisms. At any rate, the fatigue behavior of processed components was found to be significantly improved, thereby proving the suitability of FBP process as alternative mechanical technique to enhance fatigue life of components made from high strength aluminum alloy.

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