Results 1 - 10 of 9152
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[en] Some simple considerations of the total volumetric wear rates measured in tool life tests using radioactive tools provided information on the separate contributions of flank and crater wear effects. In orthogonal cutting tests with irradiated high speed steel tools there was reasonable agreement between the results obtained using the present approach and those obtained using the Hake-Opitz method of flank-crater separation. (Auth.)
[en] In this colloquium are reviewed the development of hard materials and hardening of nuclear components undergoing friction to improve wear resistance for example primary coolant circuit vanes and particularly the development of nickel base alloys as a substitute to cobalt base alloys
[fr]Ce colloque traite du developpement des materiaux durs et des traitements de surface des composants de reacteur subissant des frottements pour reduire l'usure par exemple les vannes de circuit primaire de refroidissement et particulierement le developpement d'alliage a base nickel pour remplacer les alliages durs au cobalt
[en] The erosion wear behaviors of unboiled (UB) and boiled eggshells filler reinforced epoxy composites have been characterized. The eggshells epoxy composites have been fabricated using a hand layup technique and the samples have been exposed to different environmental conditions i.e. dry, saline, mineral, kerosene and subzero temperature. To examine the effect of the above mentioned environmental conditions at different impingement angles (30, 45, 60, and 90∘) three different particle velocities (v = 86 m/s, 101 m/s and 119 m/s) were selected for the erosion wear behavior. The highest erosion rate is found at 60∘ impingement angle, which indicates the semi-brittle erosion nature of eggshells epoxy composites. The impingement angle and impact velocity have a notable influence on erosion rate. A fruitful effect of filler addition is observed on the erosion wear rate of composites. The erosion rates of unboiled and boiled eggshells epoxy are compared. The 4 wt% unboiled eggshells filler content shows the highest wear resistance in dry condition. The exposure of composites in different environmental conditions had a negative effect on erosion rate.
[en] Silicon nitride which can be expected to replace the conventional material for scaling the shaft of Reactor Coolant Pump is tested in elevated temperature water to investigate its wear resistance. To utilize the silicon nitride at the sliding part in nuclear environment, wear behavior in the elevated temperature water should be checked. The effect of temperature on the wear behaviour of silicon nitride sliding on the same material in water were investigated in the range from room temperature to 200 .deg. C under the corresponding saturated vapor pressure. Both the specific wear rate and the friction coefficient increased at elevated temperature. The grains peel our from the wear surface at high temperature by the dissolution of inter-granular impurities, and this may be reason of high local stress on the asperity, which causes the high friction coefficient
[en] Highlights: → The influence of wear parameters on the wear rate of RLDPE were investigated. → The predicted wear rate of the RLDPE and it composites were found to lie close to that experimentally observed ones. → The results showed that the addition of bagasse ash as filler materials in RLDPE composites increase the wear resistance. -- Abstract: The tribological behaviour of recycled low density polyethylene (RLDPE) polymer composites with bagasse ash particles as a reinforcement was studied using a pin-on-disc wear rig under dry sliding conditions. The influence of wear parameters like, applied load, sliding speed, sliding distance and percentage of bagasse ash fillers, on the wear rate were investigated. A plan of experiments was performed to acquire data in a controlled way. Scanning electron microscope was used to analyse the worn surface of the samples. Linear regression equation and analysis of variance (ANOVA) were employed to investigate the influence of process parameters on the wear rate of the samples. The predicted wear rate of the RLDPE and it composites were found to lie close to that experimentally observed ones. The confirmation of the experiments conducted using ANOVA to verify the optimal testing parameters show that sliding speed and applied load had significant effect on the wear rate. The results showed that the addition of bagasse ash as filler materials in RLDPE composites increase the wear resistance of the composite greatly.
[en] The concept of driven alloys is introduced and examples are given for alloys under irradiation or under high energy ball milling. Both real and computer experiments show that the stationary configuration of alloys under external forcing depends on the overall temperature, on the ratio of the ballistic to the thermally activated atomic jump frequency, and on the space and time correlation of the ballistic jumps. As well as temperature the description of driven phase transformations requires a new control parameter : the intensity of forcing. The latter is shown to be the irradiation flux for alloys under irradiation and the momentum transferred per unit time to an elementary volume of matter, under milling. We show how to use these concepts to address the wear rate of swift train wheels (TGV): it is found that the wear rate is proportional to the intensity of forcing. (authors)
[en] The factors that significantly affect the wear resistance of components in the cylinder–piston group are established by experiment and rank correlation. In the operation of the cylinder–piston group, vibration greatly intensifies the wear.