High Temperature Tribology of Plasma Nitrided T91 Alloy Steel

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21220%2F16%3A00242826" target="_blank" >RIV/68407700:21220/16:00242826 - isvavai.cz</a>

Result on the web

—

DOI - Digital Object Identifier

—

Result language

angličtina

Original language name

High Temperature Tribology of Plasma Nitrided T91 Alloy Steel

Original language description

The ferritic steel (T91) are often used as material for super heater tubes in thermal power plants. Surface of the tubes is during combustion at temperature around 750 ºC exposed to erosion and wear which are caused by the presence of abrasive particles, e.g. quartz and FeS2 from coal fuel or Al2O3 from mineral constituents in the fly ash. Therefore the study of wear resistance at high temperature is one of the essential criteria to determine the life of component made from T91 alloy steel. The research was focused on the effect of elevated temperature on tribology properties. Steel was tested in as received condition, and after plasma nitriding. The experiments were conducted using high temperature pin-on-disc tribometer. Each sample was tested at a constant linear speed and at constant load. Testing temperature was varied from 25 °C to 750 ºC. Plasma nitrided samples were produced using industrial system. The microstructure of the samples was examined using light microscopy and electron microscopy equipped with EDS and WDS. The profile of wear tracks and surface roughness were analysed by optical profilometer. The hardness of the samples was measured by micro and nano hardness tester. The microstructure of the tested specimens was not changed before and after tribology tests. Base material specimens have the highest coefficient of friction and wear rate at the room temperature. As temperature increases, the formation of the oxide layer reduces the wear rate and friction of the specimens. Plasma nitrided sample which had high hardness at room temperature shows that the nitrided layer reduced wear rate significantly at room temperature, but this effect decreases with increasing temperature testing. To understand this behaviour was analysed chemical composition from cross-section of nitrided layer depending on the increasing temperature.

Czech name

—

Czech description

—

Type

O - Miscellaneous

CEP classification

JK - Corrosion and material surfaces

OECD FORD branch

—

Project

<a href="/en/project/LO1207" target="_blank" >LO1207: Support of Sustainability of the Innovation Centre of Diagnostics and Applications of Materials at CTU-FME in Prague</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů