Fatigue Behavior Of Stainless Steel Research Articles

Low-cycle fatigue behaviour of ribbed 1.4362 duplex stainless steel reinforcement

To investigate the fatigue behaviour of stainless steel (SS) reinforcement, monotonic tensile and cyclic fatigue loading tests on 1.4362 duplex SS bars with diameters of 12 mm, 16 mm, and 20 mm are conducted. To keep the characteristics of reinforcement used in engineering construction, the specimens remain unprocessed. Two loading schemes for cyclic tests are considered in this work: (i) constant strain-amplitude, and (ii) variable strain-amplitude. The Ramberg-Osgood model was used to fit the experimental results. The strain-based and energy-based fatigue life equations are obtained. The strain-based fatigue life equation is compared with the present fatigue life estimation equations. Moreover, the ReinforcingSteel material model in OpenSees is calibrated with the experimental data. The results show that SS bars under cyclic experience hardening followed by softening. The bar diameter does not significantly affect the fatigue life prediction. The modified fatigue life equation suggests that SS bars have better fatigue resistance than conventional steel (CS) bars. The numerical analysis indicates that the calibrated steel material model (i.e. ReinforcingSteel) can produce a good simulation of SS bars under cyclic loading. It can improve the accuracy of numerical models of concrete components reinforced by SS bars.

Experimental study on mechanical properties and low-cycle fatigue behaviour of stainless steels subjected to salt spray and dry/wet cycle

This paper presents experimental studies on the mechanical properties and low-cycle fatigue behaviour of corroded austenitic stainless steel (304) and ferritic stainless steel (430). Tensile and low-cycle fatigue tests are conducted on 28 specimens. The corrosion process of the specimens is finished by using salt spray and dry/wet cycle tests. In the tensile tests, the key parameters of the constitutive model proposed by both Rasmussen and Gardner were obtained for austenitic stainless steel (304) and ferritic stainless steel (430). In the low-cycle fatigue test, the relationships of the stress amplitude and fatigue life of the specimens were obtained. The relationships of the mass loss, corrosion rate and cross-sectional area loss with the corrosion time are established. The influences of corrosion pits and fatigue cracks on the low-cycle fatigue behaviour of these two materials are studied through both macro and micro fracture morphology analysis. It is found that compared with the salt spray, the dry/wet cycle condition causes more degradation on the strength and fatigue life of the ferritic stainless steel (430). The stress concentration and notch effect of corrosion pits are the main reasons for the degradation in fatigue life of ferritic stainless steel (430). Moreover, current codes Eurocode 3 (EC3), Australian Standard (AS), BSI Standard (BSI) and DNV Standard (DNV) could not provide accurate fatigue life assessment for these two materials after salt spray and dry/wet cycle corrosions.

High-cycle and very-high-cycle fatigue behavior of a stainless steel for air-conditioning compressor valve plates

PurposeThe investigations could guide the structural design and fatigue life prediction of air-conditioning compressor valve plates.Design/methodology/approachThe High-Cycle Fatigue (HCF) and Very-High-Cycle Fatigue (VHCF) behaviors of stainless steel used for air-conditioning compressor valve plates were investigated. Monotonic and cyclic loading conditions were designed to explore the fatigue responses according to the load characteristics of the structure.FindingsThe crack initiation can be observed as the arc-shaped cracks at both sides of specimens and Y-shaped crack bifurcation in the specimens. Moreover, the middle section and the cracks at both ends are not connected to the surface of the specimen. The stress-life results of the materials under two directions (vertical and horizontal) were provided to examine the difference in fatigue strength.Originality/valueMonotonic and cyclic loading conditions were designed to explore the fatigue responses according to the load characteristics of the structure. Based on the experimental data, the results indicate that specimens under cyclic loading conditions could demonstrate better mechanical performance than static loadings.

Influences of Horizontal and Vertical Build Orientations and Post-Fabrication Processes on the Fatigue Behavior of Stainless Steel 316L Produced by Selective Laser Melting.

In this paper, the influences of build orientation and post-fabrication processes, including stress-relief, machining, and shot-peening, on the fatigue behavior of stainless steel (SS) 316L manufactured using selective laser melting (SLM) are studied. It was found that horizontally-built (XY) and machined (M) test pieces, which had not been previously studied in the literature, in both stress-relieved (SR) or non-stress-relieved (NSR) conditions show superior fatigue behavior compared to vertically-built (ZX) and conventionally-manufactured SS 316L. The XY, M, and SR (XY-M-SR) test pieces displayed fatigue behavior similar to the XY-M-NSR test pieces, implying that SR does not have a considerable effect on the fatigue behavior of XY and M test pieces. ZX-M-SR test pieces, due to their considerably lower ductility, exhibited significantly larger scatter and a lower fatigue strength compared to ZX-M-NSR samples. Shot-peening (SP) displayed a positive effect on improving the fatigue behavior of the ZX-NSR test pieces due to a compressive stress of 58 MPa induced on the surface of the test pieces. Fractography of the tensile and fatigue test pieces revealed a deeper understanding of the relationships between the process parameters, microstructure, and mechanical properties for SS 316L produced by laser systems. For example, fish-eye fracture pattern or spherical stair features were not previously observed or explained for cyclically-loaded SLM-printed parts in the literature. This study provides comprehensive insight into the anisotropy of the static and fatigue properties of SLM-printed parts, as well as the pre- and post-fabrication parameters that can be employed to improve the fatigue behavior of steel alloys manufactured using laser systems.

Analysis of fatigue behaviour of stainless steels under hydrogen influence

Three stainless steels – ASTM 304, 316 and 316L - used in hydrogen utilization equipment are under investigation at conditions of tension-compression, rotating-bending and fretting fatigue. Fatigue tests are carried out with hydrogen charged and uncharged specimens. Hydrogen charging includes cathodic type of charging and exposure to high pressure hydrogen gas. The experiments under rotating bending and tensioncompression fatigue are conducted under different frequencies in three different laboratories: at The University of Chemical Technology and Metallurgy, Sofia, Bulgaria; at Sandia National Laboratory, California and The University of Tufts, Medford, Massachusetts, USA; The HYDROGENIUS Institute at Kyushu University, Japan. The fretting fatigue tests are presented by The HYDROGENIUS Institute at Kyushu University, Japan. The obtained results are presented in Wohler curves complemented by plots Short fatigue crack length– Number of cycles and “Tangential force coefficient–Stress amplitude”. The found fatigue characteristics are analyzed and compared at different loading conditions, showing the best performance of Steel 316L.

Fatigue Crack Behavior of Stainless Steel 304 by the Addition of Carbon Nanotubes

Fatigue is the main source of almost half of whole mechanical failures. This research investigated the effect on cyclic fatigue behavior of stainless steel 304 (SS304) when including carbon nanotubes (CNTs) at the crack tip. The cyclic fatigue tests were conducted on compact tension (CT) specimens to establish the relationship between crack growth and the number of cycles (a‐N). It is found that the incorporation of a small amount of CNTs increased the fatigue life of the SS304/metal. Micrographs showed that the enhancement in fatigue life is caused by CNTs dense arrangement around the crack tip, entangled with each other, and finer grain size. Smooth bonding at the interface of the CNTs and SS304 grains is also observed.

Fatigue Behaviour of Stainless Steel Used for Turbine Runners

The key ingredient for any turbine runners design procedure and failure analysis is the material and its mechanical and fatigue properties. Starting from this observation, a series of static and dynamic tests were performed on the T10CuNiCr180 stainless steel after more than three decades of service. The fatigue tests were carried out under constant amplitude at a stress ratio of 0.1 and a frequency of 20 Hz. In the high cycle fatigue range, the S-N median curve was plotted and the fatigue limit for 3106cycles to failure was determined at 93.35 [MPa] expressed in stress amplitude. The casting and welding defects that were observed on fracture surfaces explained this lower fatigue limit. The fatigue crack growth tests were performed on compact tension specimens and a three-parameter model was used to plot the crack length versus number of cycles curves. In addition, the material constants from Paris law were determined. Finally, the experimental results are compared against published data for another stainless steel.

Effects of hydrogen water chemistry on corrosion fatigue behavior of cold-worked 304L stainless steel in simulated BWR coolant environments

Corrosion fatigue behavior of stainless steel 304L (SS304L) in a simulated BWR coolant with hydrogen injection was investigated. Hydrogen water chemistry slightly mitigated the corrosion fatigue degradation of the as-received SS304L specimens, but, on the contrary, it slightly increased the corrosion fatigue crack growth rates (CFCGRs) of the cold-worked specimens. All the CFCGR-tested specimens showed similar fracture features, except for the amounts of deposited corrosion debris. The results indicated that decreasing the oxygen concentration of water environment is not an effective measure to suppress the fatigue crack growth rate of cold-worked SS304L. The CFCGRs of the SS304L were determined by an interaction between corrosion, oxide-induced crack closure and cold work in corrosive environments. At a specific level of reduction, cold work could enhance the corrosion fatigue resistance of SS304 both in the air-saturated and HWC coolant environments.

Effects of prior cold working on low cycle fatigue behavior of stainless steels, titanium alloy timetal 834 and superalloy IN 718: A review

This paper gives a brief review of the efforts made to study the effects of cold rolling on low cycle fatigue (LCF) behavior of stainless steels, titanium alloy Timetal 834 and Ni-Fe based Super alloy IN 718 at different temperatures and different strain amplitudes. Low Cycle Fatigue tests on cold worked 316L stainless steel at various temperatures from room temperature to 923K have been reported. In all tests the effect of 20% prior cold work(PCW) on LCF behavior of type 316L (N) stainless steel had been studied at 873K under total axial strain controlled mode in air at strain amplitudes from ±0.25% to ±1.0%. Fatigue life in the solution annealed condition was similar to that of the PCW material at higher strain amplitudes (≥0.5%) while at lower strain amplitudes the PCW material exhibited longer life. The influence of PCW on LCF behavior of type 304 and AISI 304LN stainless steel was studied at various temperatures and it was observed that the fatigue life was strongly dependent on prior cold work, temperature, and strain amplitude employed. Cold rolling of the titanium alloy Timetal 834 and age hardenable Ni-Fe-based superalloy IN 718 has been found to cause marked enhancement in LCF life at low strain amplitude and eliminate the bilinearity from the Coffin-Manson(C-M) relationship. Work carried on this aspect, however is very limited particularly in the case of Titanium alloys and Ni-Fe based Superalloy IN 718

407 ステンレス鋼の二段多重変動応力疲労に及ぼす水素の影響(GS 材料力学II)

407 ステンレス鋼の二段多重変動応力疲労に及ぼす水素の影響(GS 材料力学II)

1121 ステンレス鋼の二段多重変動応力下の疲労挙動に対する水素の影響(OS11-5 材料の疲労挙動と損傷評価-環境-)

1121 ステンレス鋼の二段多重変動応力下の疲労挙動に対する水素の影響(OS11-5 材料の疲労挙動と損傷評価-環境-)

Fatigue Behaviour of a Stainless Steel Based on Energy Measurements

In this paper the low cycle fatigue behaviour of an AISI 304L stainless steel is analysed on the basis of energy concepts. In particular during the fatigue tests different forms of energy in a unit volume of material per cycle involved in the fatigue process were measured: the mechanical energy expended was evaluated from the area of the hysteresis loops, while the energy released as heat by the specimen to the surroundings was estimated from surface temperature measurements by means of an infrared camera. By subtracting the mechanical input energy and that released as heat, the energy stored in a unit volume of material at fracture was calculated for each tested specimen. The mean value obtained from different specimens is in agreement with the energy absorbed by the material in a static test.

High temperature bending fatigue behavior of stainless steels for automotive exhaust

Abstract Continually increasing working temperatures and a growing need for greater efficiency and reliability of automotive exhaust system require immediate investigation into the high temperature fatigue properties of heat resisting stainless steels. In this study, evaluation method of high temperature bending fatigue life has been established and S–N curves for ferritic stainless steels, such as 409L, 436L and 429EM STS, produced by POSCO have been evaluated at the temperatures of 600 and 800 °C, which are typical temperatures of exhaust system exposed during operation of a vehicle. Endurance limit of 429EM was found to be higher than the other two stainless steels and significantly reduced with increasing temperature, from 150 MPa at 600 °C to 65 MPa at 800 °C. Thickness effect on the fatigue life has also been investigated by varying the thickness of specimen and was found insensitive within the thickness range from 1 to 2 mm.

Effect of Absorbed Hydrogen on Torsional Fatigue Behavior of Stainless Steels (Examination by Continuous Cathodic Polarization)

The effect of absorbed hydrogen on the torsional fatigue in high cycle region was studied under continuous cathodic polarization condition using three kinds of austenitic stainless steels SUS304, SUS316 and SUS316L. The tensile strengths of these materials were varied into different levels by work hardening, hot drawing and solution heat treatment. The absorbed hydrogen gave a detrimental effect in the case of hardened materials and the fatigue strength was substantially lowered irrespective of chemical composition. In a solution heat-treated material, however, no significant effect was observed. The fatigue behavior of an actual coil spring made of work hardened SUS316 was studied as an application of work hardened material to a component of a hydrogen utilization machine. The fatigue strength was much more significantly lowered than in the case of plain specimen under cathodic polarization. Small meshwork groove existing on the surface of actual spring acted as a defect. This resulted in a significant reduction of fatigue life under cathodically polarized condition. These results suggested that high tensile strength and small defect were detrimental factors for the torsional fatigue of work hardened austenitic stainless steel used in hydrogen environment.

Influence of CrN Film Surface Characteristics on Fatigue Behavior of Stainless Steel Coated with CrN Film by AIP Method

Influence of CrN Film Surface Characteristics on Fatigue Behavior of Stainless Steel Coated with CrN Film by AIP Method

315 液体水銀中におけるステンレス鋼の疲労挙動(関東支部 茨城講演会)

315 液体水銀中におけるステンレス鋼の疲労挙動(関東支部 茨城講演会)

塩水中におけるフェライト/オーステナイト相比率の異なるステンレス鋼の疲労挙動

塩水中におけるフェライト/オーステナイト相比率の異なるステンレス鋼の疲労挙動

室温大気中におけるフェライト/オーステナイト相比率の異なるステンレス鋼の疲労挙動

室温大気中におけるフェライト/オーステナイト相比率の異なるステンレス鋼の疲労挙動

619 フェライト・オーステナイトの相比率の異なるステンレス鋼における疲労挙動 : 第 2 報 塩水中の場合

619 フェライト・オーステナイトの相比率の異なるステンレス鋼における疲労挙動 : 第 2 報 塩水中の場合

Effects of Alumina Coatings on the Fatigue Behaviors of Stainless Steel.

A plane bending fatigue test was conducted in air to investigate fatigue behaviors of stainless steel (SUS304) coated with alumina by the plasma-chemical vapor deposition (P-CVD) method and ion-plating, one of the physical vapor deposition (PVD) methods, respectively. Although some difference in extent existed depending upon the coating treatments, an increase in the fatigue limit of coated specimens as compared with that of the base metal was observed. Crack initiation in the coated specimen was delayed or prevented by the hard coating film on the specimen surface, because it acts as a barrier to the gliding of dislocations during fatigue, and therefore to the formation of slip bands. The fatigue strength of the coated specimen depended largely upon the suppression effect of slip deformation and the damage behavior of the coating films. In the case of the ion-plated specimen, fatigue cracks were induced at the base metal surface, where flaws in the coating film could not suppress the slip band formation.