نتایج جستجو برای: wear at high temperature
تعداد نتایج: 5191141 فیلتر نتایج به سال:
The tribology of an open system at temperatures ranging between 3 °C and -35 °C, with and without snow, was investigated using a pin-on-disc tribometer mounted in a temperature-controlled environmental chamber. The relationship between the microstructure and ductility of the materials and the tribology at the contacting surfaces was investigated. The study shows that during continuous sliding, ...
the purpose of the present study was to investigate the relationship between fear of negative evaluation (fne) and communication strategies (css) among iranian efl learners. it was aimed to examine the differences in the use of communication strategies between speakers with high or low degree of fear of negative evaluation. the current study was a case study consisting of 10 english learners at...
abstract the present study was conducted to examine the effect of proficiency on students interaction while carrying out the grammar-based task(s) in collaboration. in particular, the study examines whether the level of proficiency affects the learners’ focus of attention to grammatical and lexical features. the study takes a further step and examines whether there is any difference in the use...
in this study, in order to investigate the effect of increasing the manganese content on microstructure and mechanical properties of high manganese austenitic steels, three alloys with successive increases in weight percentages of manganese (7.55, 13.1, and 16.5) and carbon (0.8 and 1.2) were cast in the presence of a constant amount of chromium (1.5 wt.%) and silica (0.6 wt.%). the samples exp...
In this study carburizing and boronizing processes were applied to powder metallurgy steel specimens and the mechanical and tribological properties of the substrate and coatings were evaluated under various process conditions.
The specimens, made from industrial test pieces, were carburized in a powder pack for a duration of 2-5 hrs at 850-950 ˚C. Similar specimens were pack boronized for 4 ...
Part thermal damage is a process limitation in finish hard turning and understanding process parameter effects, especially, tool wear, on cutting temperatures is fundamental for process modeling and optimization. This study develops an analytical model for cutting temperature predictions, in particular, at the machined-surfaces, in finish hard turning by either a new or worn tool. A mechanistic...
Modern lubricants face the task of providing lubrication over a wide range of temperatures, and extreme engine temperatures can exceed the thermal degradation limits of many engine oils. Soft metal additives can extend the life of engine oils at very high temperatures by providing solid lubrication to contacting surfaces. We report a new silver–organic complex which contains a high metal conten...
INTRODUCTION Polytetrafluoroethylene (PTFE), a highly crystalline polymer with melting temperature around 330°C, possesses unique properties. Chemically inert, it has high chemical and heat resistance with upper service temperature around 260°C. Since its invention it has found limited applications especially as an additive because of its high molecular weight and inert surface. However, by mid...
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