Study on Mean Stress Effects for Design Fatigue Curves

2016 ◽  
Author(s):  
Seiji Asada ◽  
Takeshi Ogawa ◽  
Makoto Higuchi ◽  
Hiroshi Kanasaki ◽  
Yasukazu Takada
Keyword(s):  
Evaluation Method ◽  
Austenitic Stainless Steels ◽  
Fatigue Curve ◽  
Carbon Steels ◽  
Low Alloy Steels ◽  
Mean Stress ◽  
Research Committee ◽  
Stress Effects ◽  
Alloy Steels ◽  
Design Factors

In order to develop new design fatigue curves for austenitic stainless steels, carbon steels and low alloy steels and a new design fatigue evaluation method that are rational and have a clear design basis, the Design Fatigue Curve (DFC) subcommittee was established in the Atomic Energy Research Committee in the Japan Welding Engineering Society. Mean stress effects for design fatigue curves are to be considered in the development of design fatigue curves. The Modified Goodman approach for mean stress effects is used in the design fatigue curves of the ASME B&PV Code. Tentative design fatigue curves were developed and studies on the effect of mean stress and design factors are on-going. Development of design fatigue curves, effect of mean stress and design factors is needed to establish a new fatigue design evaluation method. The DFC subcommittee has studied correction approaches for mean stress effects and the approaches of modified Goodman, Gerber, Peterson and Smith-Watson-Topper were compared using test data in literature. An appropriate approach for mean stress effects are discussed in this paper.

Study on a New Design Fatigue Evaluation Method

2015 ◽  
Author(s):  
Seiji Asada ◽  
Takashi Hirano ◽  
Takehiko Sera
Keyword(s):  
Evaluation Method ◽  
Austenitic Stainless Steels ◽  
Carbon Steels ◽  
Design Evaluation ◽  
Low Alloy Steels ◽  
Mean Stress ◽  
Research Committee ◽  
Fatigue Design ◽  
Fatigue Evaluation ◽  
Design Factors

In order to develop new design fatigue curves for austenitic stainless steels, carbon steels and low alloy steels and a new design fatigue evaluation method that is rational and has a clear design basis, the Design Fatigue Curve (DFC) subcommittee was established in the Atomic Energy Research Committee in the Japan Welding Engineering Society. Tentative design fatigue curves were developed and studies on the effects of mean stress and design factors are ongoing. Design fatigue curves, including the effects of mean stress and design factors, are needed to establish a new fatigue design evaluation method. This paper describes the study on the new fatigue design evaluation method.

Plan and Status of Development of Design Fatigue Curves: Phase 1

2013 ◽  
Author(s):  
Seiji Asada ◽  
Akihiko Hirano ◽  
Masao Itatani ◽  
Munehiro Yasuda ◽  
Takehiko Sera ◽  
...  
Keyword(s):  
Stainless Steels ◽  
Phase 1 ◽  
Austenitic Stainless Steels ◽  
Fatigue Curve ◽  
Carbon Steels ◽  
Low Alloy Steels ◽  
Energy Research ◽  
Research Committee ◽  
Engineering Society ◽  
Alloy Steels

In order to develop and propose new design fatigue curves for austenitic stainless steels, carbon steels and low alloy steels that are rational and have clear design basis, Design Fatigue Curve (DFC) subcommittee has been established in the Atomic Energy Research Committee in the Japan Welding Engineering Society and the study on design fatigue curves are going on. This paper introduces the plan and status of the activities of the DFC subcommittee.

Development of New Design Fatigue Curves in Japan: Proposal of a New Fatigue Evaluation Method

2018 ◽  
Author(s):  
Seiji Asada ◽  
Akihiko Hirano ◽  
Toshiyuki Saito ◽  
Yasukazu Takada ◽  
Hideo Kobayashi
Keyword(s):  
Stainless Steels ◽  
Evaluation Method ◽  
Austenitic Stainless Steels ◽  
Fatigue Tests ◽  
Carbon Steels ◽  
Low Alloy Steels ◽  
Stress Effect ◽  
Fatigue Data ◽  
Alloy Steels ◽  
Fatigue Evaluation

In order to develop new design fatigue curves for carbon steels & low-alloy steels and austenitic stainless steels and a new design fatigue evaluation method that are rational and have clear design basis, Design Fatigue Curve (DFC) Phase 1 subcommittee and Phase 2 subcommittee were established in the Atomic Energy Research Committee in the Japan Welding Engineering Society (JWES). The study on design fatigue curves was actively performed in the subcommittees. In the subcommittees, domestic and foreign fatigue data of small test specimens in air were collected and a comprehensive fatigue database (≈6000 data) was constructed and the accurate best-fit curves of carbon steels & low-alloy steels and austenitic stainless steels were developed. Design factors were investigated. Also, a Japanese utility collaborative project performed large scale fatigue tests using austenitic stainless steel piping and low-alloy steel flat plates as well as fatigue tests using small specimens to obtain not only basic data but also fatigue data of mean stress effect, surface finish effect and size effect. Those test results were provided to the subcommittee and utilized the above studies. Based on the above studies, a new fatigue evaluation method has been developed.

Proposal of Surface Finish Factor on Fatigue Strength in Design Fatigue Curve

2014 ◽  
Author(s):  
Yuichi Fukuta ◽  
Hiroshi Kanasaki ◽  
Seiji Asada ◽  
Takehiko Sera
Keyword(s):  
Surface Roughness ◽  
Tensile Strength ◽  
Stainless Steel ◽  
Fatigue Strength ◽  
Surface Finish ◽  
Fatigue Curve ◽  
Low Alloy Steels ◽  
Mean Stress ◽  
Alloy Steels ◽  
Surface Finish Effect

The published papers related to the effects of surface finish on fatigue strength are reviewed in order to formulate its factor in the design fatigue curve in air environment. Firstly, some of regulations and literatures were examined to verify the surface finish effect on fatigue strength and formulation of that in design fatigue curve. The fatigue strength of carbon and low alloy steels is decreased with an increase of its surface roughness and tensile strength but that of stainless steel is not decreased except for special conditions. After screening the data of carbon and low alloy steels, a surface finish factor is formulated with these data which is a function of tensile strength, surface roughness and mean stress.

Environmental Fatigue Evaluation for Interface of Dissimilar Metal Welded Piping

2017 ◽  
Author(s):  
Dae Geon Lee ◽  
Dae Soo Kim ◽  
Kyeong Jin Yang ◽  
Joon Ho Lee ◽  
Seong Cheol Jang
Keyword(s):  
Evaluation Method ◽  
Austenitic Stainless Steels ◽  
Carbon Steels ◽  
Nuclear Industry ◽  
Low Alloy Steels ◽  
Plant Design ◽  
Dissimilar Metal ◽  
Dissimilar Metal Welding ◽  
Fatigue Evaluation ◽  
Metal Welding

Environmental fatigue evaluation is a key technology to extend Nuclear Power Plant design life. Since USNRC issued the RG 1.207 in 2007, many studies on fatigue evaluation in Light water Reactor coolant environments have been carried out by referencing documents such as NUREG/CR-6909, EPRI-TR-1025823, ASME BPVC Sec. III NB-3600/3200 Code, ASME Code Case, and so on. These documents presented environmental fatigue evaluation methods about each single-metal such as carbon steels, low-alloy steels, nickel-chromium-iron (Ni-Cr-Fe) alloys, and austenitic stainless steels. However, the environmental fatigue evaluation method for interface of dissimilar metal welding is mostly insufficient. Dissimilar metal welding has been widely used in nuclear industry. If environmental fatigue analysis method for dissimilar metal welding is developed, it will facilitate the design of piping for more safety. Therefore, the development of environmental fatigue evaluation for the interface of dissimilar metal welding should be studied. This paper presents environmental fatigue evaluation for the interface of dissimilar metal welded piping. The environmental fatigue evaluation for a dissimilar metal welded piping model was performed based on above documents.

UNIFLUX VCM 125

Alloy Digest ◽  
1978 ◽  
Vol 27 (1) ◽  
Keyword(s):  
Carbon Dioxide ◽  
Fracture Toughness ◽  
Weld Metal ◽  
Heat Treating ◽  
Carbon Steels ◽  
Low Alloy Steels ◽  
Electrode Wire ◽  
Molybdenum Steel ◽  
Alloy Steels ◽  
Welding Electrode

Abstract UNIFLUX VCM 125 is a continuous flux-cored welding electrode (wire) that is used to deposit 1 1/4% chromium-1/2% molybdenum steel for which it was developed. Welding is protected by a shielding atmosphere of 100% carbon dioxide. This electrode also may be used to weld other low-alloy steels and carbon steels; however, the weld metal may differ somewhat from 1 1/4% chromium-1/2% molybdenum because of weld-metal dilution. When Uniflux VCM 125 is used to weld 1 1/4% chromium-1/2% molybdenum steel, it provides 95,000 psi tensile strength at 70 F and 24 foot-pounds Charpy V-notch impact at 40 F. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating, machining, and joining. Filing Code: SA-340. Producer or source: Unicore Inc., United Nuclear Corporation.

UNIFLUX V90

Alloy Digest ◽  
1979 ◽  
Vol 28 (2) ◽  
Keyword(s):  
Carbon Dioxide ◽  
High Strength ◽  
Heat Treating ◽  
Carbon Steels ◽  
Low Alloy Steels ◽  
Nickel Steel ◽  
Steel Weld Metal ◽  
Alloy Steels ◽  
Temperature Impact ◽  
Welding Electrode

Abstract UNIFLUX V90 is a continuous flux-cored welding electrode (wire) developed to weld high-strength low-alloy steels, but it may be used to weld other low-alloy steels and carbon steels. It is used to deposit typically 2.40% nickel steel weld metal with good low-temperature impact properties. Welding is protected by a shielding atmosphere of either 75% argon-25% carbon dioxide or 100% carbon dioxide. Uniflux V90 is used widely in shipbuilding and other fabricating industries. It provides around 88,000 psi tensile strength and around 26 food-pounds Charpy V-notch impact at 60 F. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating, machining, and joining. Filing Code: SA-355. Producer or source: Unicore Inc., United Nuclear Corporation.

Proposal of Fatigue Life Equations for Carbon and Low-Alloy Steels and Austenitic Stainless Steels as a Function of Tensile Strength

2013 ◽  
Author(s):  
Hiroshi Kanasaki ◽  
Makoto Higuchi ◽  
Seiji Asada ◽  
Munehiro Yasuda ◽  
Takehiko Sera
Keyword(s):  
Tensile Strength ◽  
Fatigue Life ◽  
Stainless Steels ◽  
Room Temperature ◽  
Austenitic Stainless Steels ◽  
Low Alloy Steels ◽  
Strength Based ◽  
Fatigue Data ◽  
Current Design ◽  
Alloy Steels

Fatigue life equations for carbon & low-alloy steels and also austenitic stainless steels are proposed as a function of their tensile strength based on large number of fatigue data tested in air at RT to high temperature. The proposed equations give a very good estimation of fatigue life for the steels of varying tensile strength. These results indicate that the current design fatigue curves may be overly conservative at the tensile strength level of 550 MPa for carbon & low-alloy steels. As for austenitic stainless steels, the proposed fatigue life equation is applicable at room temperature to 430 °C and gives more accurate prediction compared to the previously proposed equation which is not function of temperature and tensile strength.

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