Fatigue Strength of Maraging Steel at Elevated Temperatures

2008 ◽  
Vol 385-387 ◽  
pp. 161-164 ◽  
Author(s):  
T. Iwamoto ◽  
Norio Kawagoishi ◽  
Nu Yan ◽  
Eiji Kondo ◽  
Kazuhiro Morino
Keyword(s):  
Elevated Temperature ◽  
Fatigue Strength ◽  
Maraging Steel ◽  
Fracture Mechanism ◽  
Elevated Temperatures ◽  
Surface Oxidation ◽  
Fatigue Tests ◽  
Age Hardening ◽  
Effect Of Temperature ◽  
Rotating Bending Fatigue

Rotating bending fatigue tests were carried out to investigate the effects of temperature on the fatigue strength and the fracture mechanism of an 18 % Ni maraging steel at room and elevated temperatures of 473K and 673K. Fatigue strength was higher at elevated temperatures than at room temperature, though static strength was decreased by softening at elevated temperature. There was no effect of temperature on crack morphology and fracture mechanism. On the other hand, during fatigue process at elevated temperature, the specimen was age-hardened and the specimen surface was oxide. That is, the increase in fatigue strength at elevated temperature was mainly caused by the increase in hardness due to age-hardening and suppression of a crack initiation due to surface oxidation.

scholarly journals Application of a √ area -Approach for Fatigue Assessment of Cast Aluminum Alloys at Elevated Temperature

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1033 ◽  
Author(s):  
Roman Aigner ◽  
Christian Garb ◽  
Martin Leitner ◽  
Michael Stoschka ◽  
Florian Grün
Keyword(s):  
Elevated Temperature ◽  
Fatigue Strength ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Damage Mechanism ◽  
Cyclic Fatigue ◽  
Fatigue Tests ◽  
Cast Aluminum ◽  
Fatigue Assessment ◽  
Cast Aluminum Alloys

This paper contributes to the effect of elevated temperature on the fatigue strength of common aluminum cast alloys EN AC-46200 and EN AC-45500. The examination covers both static as well as cyclic fatigue investigations to study the damage mechanism of the as-cast and post-heat-treated alloys. The investigated fracture surfaces suggest a change in crack origin at elevated temperature of 150 ∘ C. At room temperature, most fatigue tests reveal shrinkage-based micro pores as their crack initiation, whereas large slipping areas occur at elevated temperature. Finally, a modified a r e a -based fatigue strength model for elevated temperatures is proposed. The original a r e a model was developed by Murakami and uses the square root of the projected area of fatigue fracture-initiating defects to correlate with the fatigue strength at room temperature. The adopted concept reveals a proper fit for the fatigue assessment of cast Al-Si materials at elevated temperatures; in detail, the slope of the original model according to Murakami should be decreased at higher temperatures as the spatial extent of casting imperfections becomes less dominant at elevated temperatures. This goes along with the increased long crack threshold at higher operating temperature conditions.

Effect of Humidity on Fatigue Strength of Age-Hardened Al Alloy

2009 ◽  
Vol 417-418 ◽  
pp. 373-376
Author(s):  
T. Fukudome ◽  
Norio Kawagoishi ◽  
K. Kariya
Keyword(s):  
Fatigue Strength ◽  
Fracture Mechanism ◽  
Fatigue Tests ◽  
Shear Mode ◽  
Al Alloy ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Ultrasonic Fatigue ◽  
Rotating Bending ◽  
The Difference

Ultrasonic and rotating bending fatigue tests were carried out using plain specimens and specimens with a small blind hole for an extruded and age-hardened Al alloy 7075-T6 in different environments in order to investigate the effect of humidity on fatigue strength and fracture mechanism. Fatigue strength was decreased by high humidity under both tests. The effect of humidity on fatigue strength was larger in ultrasonic fatigue. The humidity affected both of crack initiation and propagation processes. Crack propagated in tensile mode then changed to shear mode macroscopically in all environments under ultrasonic fatigue, though it was only in tensile mode under rotating bending fatigue. These differences in fracture mechanism related to the difference in environmental effect on fatigue strength in both tests.

Improvement of Fatigue Strength of Maraging Steel by Shot Peening

2007 ◽  
Vol 348-349 ◽  
pp. 537-540
Author(s):  
Norio Kawagoishi ◽  
Takanori Nagano ◽  
M. Moriyama ◽  
Eiji Kondo
Keyword(s):  
Fatigue Strength ◽  
Maraging Steel ◽  
Shot Peening ◽  
Fine Particles ◽  
Fatigue Tests ◽  
Fracture Origin ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Points Of View

Rotating bending fatigue tests up to 108 cycles were carried out to investigate the effects of shot peening on the fatigue strength and the fracture mechanism in an 18 % Ni maraging steel by using shot particles of various sizes or hardness. Fatigue strength was increased markedly by shot peening in the wide region of fatigue life. The S-N curves showed duplex S-N properties because of the transition of fracture origin from the specimen surface in the short life region to the subsurface in the long life one. Double shot peening by using super-hard fine particles was effective to improve the fatigue strength for surface fracture, though the fatigue strength for an internal fracture was hardly influenced. These results were discussed from the points of view of effects of surface roughness, residual stress and work hardening on the fatigue strength.

Fatigue Behavior of Age-Hardening Cu-6Ni-1.5Si Alloys with Different Grain Sizes

2021 ◽  
Vol 1016 ◽  
pp. 125-131
Author(s):  
Masahiro Goto ◽  
T. Yamamoto ◽  
S.Z. Han ◽  
J. Kitamura ◽  
J.H. Ahn ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Fatigue Strength ◽  
Solution Heat Treatment ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
The Other ◽  
Age Hardening ◽  
Grain Sizes ◽  
Thermomechanical Processes

On the thermomechanical treatments of Cu-Ni-Si alloy, cold-rolling (CR) before solution heat treatment (SHT) is commonly conducted to eliminate defects in a casting slab. In addition, a rolling is applied to reduce/adjust the thickness of casting slab before SHT. In a heavily deformed microstructure by CR, on the other hand, grain growth during a heating in SHT is likely to occur as the result of recrystallization. In general, tensile strength and fatigue strength tend to decrease with an increase in the grain size. However, the effect of difference in grain sizes produced by with and without CR before SHT on the fatigue strength is unclear. In the present study, fatigue tests of Cu-6Ni-Si alloy smooth specimens with a grain fabricated through different thermomechanical processes were conducted. The fatigue behavior of Cu-Ni-Si alloy was discussed.

scholarly journals Acidovorax citrulli is sensitive to elevated temperatures during early stages of watermelon seed germination

2020 ◽  
Vol 48 (1) ◽  
pp. 11-20
Author(s):  
Mei Zhao ◽  
Ron Walcott
Keyword(s):  
Elevated Temperature ◽  
Seed Germination ◽  
Elevated Temperatures ◽  
Transmitted Disease ◽  
Effect Of Temperature ◽  
Crop Species ◽  
Inoculum Concentration ◽  
Bacterial Fruit Blotch ◽  
Acidovorax Citrulli ◽  
Germinating Seeds

Bacterial fruit blotch (BFB), caused by Acidovorax citrulli, is a seed-transmitted disease of cucurbit crop species. During seed-to-seedling transmission of BFB, A. citrulli initially grows as a saprophyte on germinating seeds and subsequently switches to a pathogenic mode. We investigated the effect of temperature on A. citrulli colonisation of germinating watermelon seeds. Seeds were vacuum-infiltrated with 106 CFU/ml A. citrulli, germinated at 28°C and 100% relative humidity, and transferred to 40°C at different times. Mean BFB incidence was significantly lower for seeds that were sown at 28°C and transferred to 40°C three days after sowing (DAS), compared with seeds incubated constantly at 28°C. Seeds showed reduced mean BFB transmission percentages when transferred from 28 to 40°C at 3 DAS, regardless of initial A. citrulli concentration. The effect of increased temperature on BFB seedling transmission was reversible regardless of the initial A. citrulli inoculum concentration. Furthermore, the A. citrulli population on germinating watermelon seedlings that were transferred from 28 to 40°C at 3 DAS was significantly lower than seedlings maintained at 28°C. We conclude that A. citrulli cells associated with germinating watermelon seeds are more sensitive to elevated temperature during the first 3 DAS relative to the later days.

Effect of temperature on the heart in the alligator

1960 ◽  
Vol 198 (4) ◽  
pp. 861-863 ◽  
Author(s):  
Charles G. Wilber
Keyword(s):  
Heart Rate ◽  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Well Being ◽  
Effect Of Temperature ◽  
Optimal Temperature ◽  
General Behavior ◽  
Colonic Temperature

Electrocardiograms were taken on 12 alligators, 18–30 inches in length. Some were exposed to elevated temperatures; the resulting ECG's were compared with controls obtained at 22°C, which were as follows: rate, 40/min.; P-R, 0.4 seconds; Q-T, 0.6 seconds; T, 0.24 second, 0.05 mv; QRS, 0.04 second. Heart rate increased with increased colonic temperature. At 34°C there was marked increase in variability of rate. Above 40°C the heart became irregular and was damaged irreversibly. Duration of T decreased with elevated temperature to about 33°C above which T was prolonged. Optimal temperature for the alligator in terms of tolerance and general behavior is between 32°C and 35°C, with a critical maximum of 38°C. Slightly above that temperature the heart became disorganized. The present results suggest that the alligator's temperature preferendum is sound with respect to cardiac well being.

Elevated Temperature Properties of Maraging Steel Plates and Welds

1971 ◽  
Vol 93 (2) ◽  
pp. 218-224
Author(s):  
N. Kenyon ◽  
E. P. Sadowski ◽  
P. P. Hydrean
Keyword(s):  
Elevated Temperature ◽  
Maraging Steel ◽  
Elevated Temperatures ◽  
High Strength Steels ◽  
High Strength ◽  
Steel Plates ◽  
Maraging Steels ◽  
Gas Tungsten Arc ◽  
Temperature Exposure ◽  
Rupture Behavior

The creep rupture behavior, and the effects of elevated temperature exposure in air and hydrogen on the subsequent room temperature properties of a 12 percent Ni-5 percent Cr-3 percent Mo maraging steel are described. Tests have been made on several heats of plate and on gas tungsten-arc, gas metal-arc, and electroslag welds. On the basis of the results obtained, maraging steels offer promise as high-strength steels for service at elevated temperatures.

Studies on Fatigue Properties of Steel with Co-Based Alloy Hardfacing Coating

2010 ◽  
Vol 118-120 ◽  
pp. 161-165
Author(s):  
Hong Xia Deng ◽  
Hui Ji Shi ◽  
Seiji Tsuruoka ◽  
Hui Chen Yu ◽  
Bin Zhong
Keyword(s):  
Fatigue Strength ◽  
Failure Mode ◽  
Failure Modes ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Main Task ◽  
Interface Failure ◽  
Coating Failure ◽  
Rotating Bending Fatigue ◽  
Stellite 12

The main task of this paper was to evaluate the influence of hardfacing technique and service temperature on the fatigue properties of heat-resistant steel X45CrSi9-3 coated with Co-based alloy Stellite 12. The results of rotating bending fatigue tests showed that at room temperature (RT), the fatigue strength of specimens welded by the acetylene gas welding (AGW) was lower than that of specimens welded by the plasma transferred arc welding (PTAW). For PTAW specimens, the fatigue strength at 500oC was much higher than that at RT. Two failure modes were presented, one was termed as the coating failure mode at RT and the other was termed as coating-interface failure mode at 500oC. The fatigue life prediction was conducted by using a modified Murakami’s model.

scholarly journals Study on Tensile Properties of CFRP Plates under Elevated Temperature Exposure

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1995 ◽  
Author(s):  
Yongxin Yang ◽  
Yanju Jiang ◽  
Hongjun Liang ◽  
Xiaosan Yin ◽  
Yue Huang
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Elevated Temperature ◽  
Tensile Properties ◽  
Failure Mode ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Effect Of Temperature ◽  
Temperature Exposure ◽  
The Impact

Elevated temperature exposure has a negative effect on the performance of the matrix resin in Carbon Fiber Reinforced Plastics (CFRP) plates, whereas limited quantitative research focuses on the deteriorations. Therefore, 30 CFRP specimens were designed and tested under elevated temperatures (10, 30, 50, 70, and 90 °C) to explore the degradations in tensile properties. The effect of temperature on the failure mode, stress-strain curve, tensile strength, elastic modulus and elongation of CFRP plates were investigated. The results showed that elevated temperature exposure significantly changed the failure characteristics. When the exposed temperature increased from 10 °C to 90 °C, the failure mode changed from the global factures in the whole CFRP plate to the successive fractures in carbon fibers. Moreover, with temperatures increasing, tensile strength and elongation of CFRP plates decreases gradually while the elastic modulus shows negligible change. Finally, the results of One-Way Analysis of Variance (ANOVA) show that the degradation of the tensile strength of CFRP plates was due to the impact of elevated temperature exposure, rather than the test error.

Proposal for the Implementation of Elevated Temperature Design Fatigue Curve for 2-1/4Cr-1Mo-V and 3Cr-1Mo-V Steels

2004 ◽  
Author(s):  
Tatsumi Takehana ◽  
Takeru Sano ◽  
Susumu Terada ◽  
Hideo Kobayashi
Keyword(s):  
Elevated Temperature ◽  
Fatigue Strength ◽  
High Strength ◽  
Fatigue Curve ◽  
Temperature Limit ◽  
Fatigue Tests ◽  
Low Alloy Steels ◽  
Alloy Steels ◽  
Elevated Temperature Design

2-1/4Cr-1Mo-V and 3Cr-1Mo-V steels have been used extensively as materials for elevated temperature and high-pressure hydro-processing reactors. These steels have both of high strength at elevated temperature and high resistance against elevated temperature hydrogen attack due to the addition of vanadium. The operating temperature of these reactors is between 800 and 900deg.F. The fatigue evaluations of these reactors per ASME Sec. VIII Div.2 and Div.3 can’t be performed in spite of demand for fatigue analysis because the temperature limit of design fatigue curve in ASME Sec. VIII Div.2 and Div.3 for carbon and low alloy steels is 700deg.F. Results of load and strain controlled fatigue tests conducted over the temperature range from room temperature to 932deg.F (500deg.C) are reported for 2-1/4Cr-1Mo-V and 3Cr-1Mo-V steels. These data were compared with data for 2-1/4Cr-1Mo steels available from the literatures. The fatigue strength for a 2-1/4Cr-1Mo-V steel in high cycle region is higher than that for 2-1/4Cr-1Mo steels and in low cycle region is lower. The fatigue strength for a 3Cr-1Mo-V steel is almost same as that for 2-1/4Cr-1Mo-V steels. Therefore an elevated temperature design fatigue curve for 2-1/4Cr-1Mo-V and 3Cr-1Mo-V steels is newly proposed. It is found from the case study that the different fatigue life can be predicted by using different mean stress correction procedure.

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