Effect of Slag Composition on Fatigue Life of High Speed Wheel Steel

2013 ◽  
Vol 675 ◽  
pp. 264-269
Author(s):  
Yu Tang
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Oxide Inclusion ◽  
Wheel Steel ◽  
Al2o3 Content ◽  
Confocal Laser ◽  
Composition Analysis ◽  
In Situ Observation

In order to improve fatigue life of wheel steel, secondary-refining process was done with Al-deoxidation and slag of high basicity, high Al2O3 content and low oxidizing property. By morphology observation and composition analysis with FESEM, it is found that during LF-VD process, by slag-steel-inclusion interaction, Al2O3 inclusions could transform to MgO-Al2O3 spinel, and later on to CaO-MgO-Al2O3 inclusions, which are inclined to be eliminated by floatation, lowering T[O] content to 0.0007%, enhancing fatigue life of wheel steel. By In-Situ observation with CONFOCAL laser scanning microscope, it is found that MnS precipitates during solidification process, which would core oxide inclusion to form MnS-oxide complex inclusion, contributing to fatigue life improvement of wheel steel. By INSTRON fatigue testing machine, it is found that by successful inclusion control, tested samples achieve ultra-high cycle of 108 above, realizing experimental purpose of improving fatigue life of wheel steel, boosting domestic production process of CRH high speed wheel steel.

Effect of Slag Composition on Total Oxygen of High Speed Wheel Steel

2013 ◽  
Vol 690-693 ◽  
pp. 114-117
Author(s):  
Yu Tang
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Wheel Steel ◽  
Al2o3 Content ◽  
Inclusion Interaction ◽  
Secondary Refining ◽  
Positive Factor ◽  
Improve Fatigue

In order to improve fatigue life of wheel steel, secondary-refining process is done with Al-deoxidation and slag of high basicity, high Al2O3 content and low oxidizing property. By slag-steel-inclusion interaction, harmful inclusions could be controlled well to be eliminated by floation, lowering T[O] content to 0.0007% in round billets, enhancing fatigue life of wheel steel. It is found that (Al2O3) in slag is positive factor for decrease of T[O], while (CaO)/(Al2O3), (SiO2) in slag and [Al]s in molten steel is negative factor for it. As a result, by INSTRON fatigue testing machine, tested steel samples achieve ultra-high cycle of 108 above, realizing experimental purpose of improving fatigue life of wheel steel.

scholarly journals A Study on the Effect of Alumina on the Morphology and Reduction Behavior of Sinter by In Situ Observation

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 740
Author(s):  
Sang Gyun Shin ◽  
Wan Ho Kim ◽  
Dong Joon Min
Keyword(s):  
Reduction Rate ◽  
Al2o3 Content ◽  
Confocal Laser ◽  
In Situ Observation ◽  
Sintering Process ◽  
Reduction Behavior ◽  
Reducing Gas ◽  
Interfacial Chemical Reaction ◽  
Reaction Routes

The effects of Al2O3 content on the morphology and reducibility of sinter were respectively investigated using confocal laser microscopy and thermogravimetric analysis at 1273 K under CO gas. To understand the effects of the sintering process, separate samples were prepared via the equilibrium and metastable reaction routes. In the equilibrium samples, the addition of Al2O3 led to the formation of the silico-ferrite of calcium and alumino phase and a decrease in the reduction rate due to the lowered reactivity of iron oxide. In contrast, in the metastable samples, the reduction rate increased after the addition of 2.5 mass% Al2O3. The addition of Al2O3 decreased the fraction of the liquid phase and increased the fraction of pores in the sample. As a result, the reduction rate is proportional to the Al2O3 content owing to the changes in the sinter morphology. In determining the reduction rate of the sinter, the influence of the microstructure on the diffusion of the reducing gas is more significant than that of the interfacial chemical reaction due to the formation of the SFCA phase. The microstructure changes of the sinter with the addition of Al2O3 and the corresponding reduction behaviors are further discussed.

scholarly journals Impacts of Thermal and Mechanical Cycles on Electro-Thermal Anti-Icing System of CFRP Laminates Embedding Sprayable Metal Film

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1589
Author(s):  
Rongjia Li ◽  
Wang Xu ◽  
Dalin Zhang
Keyword(s):  
Fatigue Life ◽  
Metal Film ◽  
Fatigue Testing ◽  
Aerodynamic Force ◽  
Testing Machine ◽  
Laminated Composite ◽  
Heating Element ◽  
Electric Resistance ◽  
Potential Threat ◽  
Mechanical Cycling

The aircraft electro-thermal anti-icing system that can guarantee flight safety may be affected by periodic heating and cyclic aerodynamic force during long-term flight missions, which seems to be a potential threat to ice protection. This paper aims to investigate the impacts of thermal and mechanical cycles on heating elements of the electro-thermal anti-icing system. Specimens were manufactured with CFRP (carbon fiber reinforced polymer) laminated composite, glass fiber prepreg and copper screen, in which sprayable metal film (SMF) was embedded as the heating element. The study focuses on electric resistance variation of SMF and functional fatigue life under the cycling load. Thermal cycling tests were carried out in an insulated chamber where the specimens were heated up to 80 °C and then cooled down to −55 °C for 1000 cycles. Mechanical cycling tests were conducted on a fatigue testing machine where the specimens were imposed on tension-compression loading for 106 cycles. Results showed that the electric resistance of SMF increased with the number of loading cycles. The resistance was increased by 20% and the heating power was decreased by 16.67% after 1000 thermal cycles. During the mechanical cycling tests, it was found that the heating element was destructed before the structural failure, which indicated that the fatigue life of function was lower than that of the structure.

Effect of [Al]s, [Mg], [Ca] in Molten Steel on Inclusion Content for High Speed Wheel Steel during LF-VD Process

2014 ◽  
Vol 898 ◽  
pp. 60-63
Author(s):  
Yu Tang
Keyword(s):  
Fatigue Life ◽  
Molten Steel ◽  
High Speed ◽  
Refining Process ◽  
Fatigue Performance ◽  
Wheel Steel ◽  
Inclusion Content ◽  
High Basicity ◽  
Secondary Refining ◽  
Improve Fatigue

In order to improve fatigue life of wheel steel, LF-VD secondary-refining process is done with Al-deoxidation and slag of high basicity, high Al2O3 content and low oxidizing property. Inclusion content would be influenced by [Al]s, [Mg], [Ca] in molten steel. It is found that Al2O3 inclusions, which are the products of Al-deoxidation, would react with [Mg], [Ca] in molten steel to transform into CaO-MgO-Al2O3 complex inclusions, which is the key for the enhancement of fatigue performance for wheel steel.

Effects of Water Jet Peening and Hardening Treatment on Fatigue Properties of SCr420

2009 ◽  
Author(s):  
Akira Shimamoto ◽  
Ryo Kubota ◽  
Sung-mo Yang ◽  
Dae-kue Choi ◽  
Weiping Jia
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Fatigue Crack Initiation ◽  
Fatigue Tests ◽  
Water Jet ◽  
Fatigue Properties ◽  
In Situ Observation ◽  
Axial Tensile ◽  
High Pressure Water Jet

An experimental study of high pressure water jet peening treatment on chromium steal SCr420 H3V2L2 is conducted to study the effects of cavitation impacts of high-speed water on fatigue crack initiation and propagation of notched specimens. There are six different kinds of specimens. First three kinds are treated with; only annealing, only water quenching, and only oil quenching. Other three kinds are treated with above heat treatment and water jet peening, respectively. An axial tensile fatigue tests’ condition is 260MPa maximum stress amplitude, 0 stress ratio and 10Hz frequency, while in-situ observation by SEM is employed. Although fatigue life of the specimens with annealing and water jet peening is shorter than that of only annealing, fatigue life of water and oil quenching with water jet peening specimens is obviously longer than those without water jet peening treatment. Water jet peening has increased residual stress inside the specimens on the latter case and raised their fatigue strength. In-situ observation on the crack tips approves above analysis.

Development of a New Fatigue Testing Machine for High Frequency Fatigue Damage Assessment

2013 ◽  
Author(s):  
Naoki Osawa ◽  
Tetsuya Nakamura ◽  
Norio Yamamoto ◽  
Junji Sawamura
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Fatigue Testing ◽  
Low Cost ◽  
Plate Thickness ◽  
Testing Machine ◽  
Fatigue Tests ◽  
Frequency Effect ◽  
Wave Load ◽  
Out Of Plane

A new simple fatigue testing machine, which can carry out fast and low-cost fatigue tests of welded joints subject to wave with high frequency vibration, has been developed. This machine is designed for plate bending type fatigue tests, and wave load is applied by using motors with eccentric mass. Springing vibration is superimposed by attaching an additional vibrator to the test specimen, and whipping vibration is superimposed by an intermittent hammering. Fatigue tests which simulate springing and whipping by a conventional servo-type fatigue testing machines are very expensive and use a large amount of electricity. If one uses these conventional machines, it is difficult to simulate superimposed stress wave forms at high speed, and it takes long hours of testing to examine the high frequency effect. In contrast, it is found that fatigue tests can be carried out in fast, i.e. waves with 10Hz or higher frequency for out-of-plane gusset welded joint specimens with 12mm plate thickness by using the developed machine. The electricity to be used for fatigue tests could be minimal, for example one thousandth of that needed for conventional machines. These results demonstrate the superiority of the developed machine.

A Study on Fatigue Behavior of SM490A Steel under Low Temperature

2007 ◽  
Vol 353-358 ◽  
pp. 142-145 ◽  
Author(s):  
Ki Weon Kang ◽  
Byeong Choon Goo ◽  
J.H. Kim ◽  
Heung Seob Kim ◽  
Jung Kyu Kim
Keyword(s):  
Fatigue Life ◽  
Low Temperature ◽  
Test Temperature ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Fatigue Tests ◽  
Static Strength ◽  
Experimental Results ◽  
Railway Vehicle

This paper deals with the fatigue behavior and its statistical properties of SM490A steel at various temperatures, which is utilized in the railway vehicle. For these goals, the tensile ad fatigue tests were performed by using a servo-hydraulic fatigue testing machine at three temperatures: +20°C, -10°C and -40°C. The static strength and fatigue limits of SM490A steel were increased with decreasing of test temperature. The probabilistic properties of fatigue behavior are investigated by means of probabilistic stress-life (P-S-N) curve and they are well in conformance with the experimental results regardless of temperature. Also, based on P-S-N curves, the variation of fatigue life is investigated and as the temperature decreases, the variation of fatigue life increases moderately.

Fatigue Damage Mechanism Analyses of Oriented Sheets of Polymethyl Methacrylate Glasses

2011 ◽  
Vol 462-463 ◽  
pp. 36-41
Author(s):  
Wei Guo Guo ◽  
Xiao Qiong Zhang ◽  
J. Su
Keyword(s):  
Fatigue Life ◽  
Polymethyl Methacrylate ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Damage Mechanism ◽  
Materials Testing ◽  
Compression Tests ◽  
Static Compression ◽  
Lower Amplitude ◽  
Notch Edge

To understand the damage mechanism and obtain the fatigue life of the oriented sheets of polymethyl methacrylate (PMMA) glasses, the quasi-static compression tests and the constant amplitude fatigue testing with two notch stress concentration factors are carried out respectively, using the CSS44100 electromechanical universal materials testing machines and a MTS servohydraulic testing machine. The damage region and fracture section of the deformed and failed sheet samples are examined with the aid of an optical microscopy. The results show that, 1) the oriented PMMA glasses drawn through vertical bi-direction have remarkable thermomechanical anisotropic characteristic, that is, it has the higher hardness and strength along the normal direction of the sheet panel, it will burst out and scatters into bigger pieces under the perforation; 2) the S-N curve of the oriented sheet specimens shows that its fatigue life is not sensitive on the notch at lower amplitude stress levels; and 3) the crack initiation of the oriented PMMA glasses often originates the interbeds area or mid region of the notch edge under fatigue cycle loading.

scholarly journals Some aspects of fretting fatigue under cyclic normal loading

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Farshad Abbasi ◽  
G. H. Majzoobi
Keyword(s):  
Fatigue Life ◽  
Fatigue Testing ◽  
Normal Load ◽  
Testing Machine ◽  
Low Frequency ◽  
Load Condition ◽  
Fretting Fatigue ◽  
Normal Loading ◽  
Drastic Effect ◽  
Fretting Damage

Fretting fatigue has been studied mainly under constant normal loading, as it requires simple equipment which can be assembled on a universal fatigue testing machine. Recently, we [1] have introduced an innovative fretting fatigue apparatus in which the contact pressure can independently be varied during the test. In a recent publication [2] we have investigated the effect of normal load frequency on fretting fatigue life of Al7075-T6 under cyclic normal load condition. It was found that the low frequency of normal load has drastic effect on fretting fatigue life. The effect, however, gradually diminishes with the frequency increase and vanishes at the frequency of around 80Hz. In another publication [3] we have compared the results of constant normal loading with those of in phase, 90° and 180° degrees out-of-phase loadings. It was found that the constant normal loading has the least fretting damage, while the maximum fretting damage occurs by in-phase loading. The results also showed that the out-of-phase loading had improving effect on fretting fatigue life with respect to the in-phase condition. Recently, Ciaverella [4] has published a discussion on our publications [2, 3]. He believes that some of our experimental results needs further discussion. Therefore, the objective of this article is to answer three main points he has raised in his article [4]. We hope that this discussion could lead to some progress.

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