Effect of hardened surface layer obtained by frictional treatment on the contact endurance of the AISI 321 stainless steel under contact gigacycle fatigue tests

Current research focuses on proportional cyclic hardening and non-Massing behaviors. The interaction of these two hardenings can result in the traditionally observed overall softening, hardening or mixed behavior exhibited for fully reversed strain controlled fatigue tests. Proportional experiments were conducted with five materials, 304 stainless steel, normalized 1070 and 1045 steels, and 7075-T6 and 6061-T6 aluminum alloys. All the materials display similar trends, but the 304 stainless steel shows the most pronounced transient behavior and will be discussed in detail. Existing algorithms for this behavior are evaluated in light of the recent experiments, and refinements to the Armstrong-Frederick class of incremental plasticity models are proposed. Modifications implemented are more extensive than the traditional variation of yield stress, and a traditional strain based memory surface is utilized to track deformation history. Implications of the deformation characteristics with regard to fatigue life estimation, especially variable amplitude loading, will be examined. The high-low step loading is utilized to illustrate the effect of transient deformation on fatigue life estimation procedures, and their relationship to the observed and modeled deformation.

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SCC Behavior at Hardened Surface Layer of 316(LC) in Water on High Temperature

Zairyo-to-Kankyo ◽

10.3323/jcorr.58.228 ◽

2009 ◽

Vol 58 (6) ◽

pp. 228-233 ◽

Cited By ~ 8

Author(s):

Kiyoko Takeda ◽

Akira Taniyama ◽

Takeo Kudo ◽

Hitoshi Uchida ◽

Jun-ichiro Mizuki

Keyword(s):

Surface Layer ◽

High Temperature ◽

Hardened Surface

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Relation between Creep Rupture Properties and Microstructures of AISI 321 Stainless Steel Forgings

Transactions of the Japan Institute of Metals ◽

10.2320/matertrans1960.4.213 ◽

1963 ◽

Vol 4 (4) ◽

pp. 213-221

Author(s):

Teishiro Oda ◽

Yuzô Katayama

Keyword(s):

Stainless Steel ◽

Creep Rupture ◽

Aisi 321 ◽

Rupture Properties

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Status of French Road Map to Improve Environmental Fatigue Rules

Volume 6: Materials and Fabrication, Parts A and B ◽

10.1115/pvp2012-78805 ◽

2012 ◽

Cited By ~ 1

Author(s):

Claude Faidy

Keyword(s):

Stainless Steel ◽

Environmental Effects ◽

Fatigue Curve ◽

Fatigue Tests ◽

Stress Effects ◽

The Past ◽

Road Map ◽

The Status ◽

Load Effects ◽

Section Viii

During the past 30 years many fatigue tests and fatigue analysis improvements have been developed in France in order to improve Codified Fatigue Rules of RCC-M and ASME Codes [1, 2]. This paper will present the major technical improvements to obtain reasonable evaluation of potential fatigue damage through EDF road map. Recently new results [3] confirm possible un-conservative fatigue material data: - High cycle fatigue in air for stainless steel, - Environmental effects on fatigue S-N curve for all materials - Fatigue Crack Growth law under PWR environment for stainless steel. In front of these new results, EDF has developed a “Fatigue Road Map” to improve the different steps of Codified fatigue rules. A periodic up-dating of proposed rules in the different French Codes: RCC-M, RCC-MRx and RSE-M with research of harmonization with other Code rules developed in USA, Japan and Germany in particular, will be done on a yearly basis. During the past 15 years, many results have been obtained through fatigue tests of stainless steel materials: - mean and design fatigue curve in air, - environmental effects on fatigue curves, - plasticity effects, - bi-axial load effects, - mean stress effects, - stress indices, - transferability from small to large specimen, - weld versus base metal. In parallel, many new developments have been made in non-nuclear pressure equipment industry: like the reference stress of ASME Section VIII or the structural stress of EN 13445. These methods are mainly well adapted to fatigue pressure cycling. In front of that situation, the French nuclear code organization needs to propose reliable rules for new design and for operating plants. Different proposals are under discussion and the status of the EDF proposals are presented in the paper. The consequences could be important for the utilities because a large part of the in-service inspection program is connected to some fatigue usage factor level between 0.5 and 1.

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