Nitriranje nehrđajućih čelika u plazmi ioniziranih plinova

master's thesis

• Title (english): Nitriding of stainless steels in plasma of ionized gases
• Author: Stjepan Vargek
• Mentor: Darko Landek (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2021-12-16, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U radu se razmatra utjecaj parametara nitriranja u plazmi na tvrdoću i dubinu nitriranog sloja na nehrđajućim čelicima. Prikazan je pregled literature o dosadašnjim istraživanjima nitriranja u plazmi nehrđajućih čelika. Ispitan je utjecaj parametara nitriranja na austenitni i martenzitni nehrđajući čelik. Ispitivana je mikrotvrdoća po površini i presjeku, hrapavost površine i provedena je analiza mikrostrukture nitriranog sloja i jezgre materijala svjetlosnom mikroskopijom. Iz provedenih ispitivanja utvrđeni su parametri nitriranja u plazmi za postizanje visoke tvrdoće površine i optimalne dubine nitriranja na nehrđajućim čelicima za konstrukcijsku primjenu. Na svim ispitnim uzorcima uočeno je povećanje površinske mikrotvrdoće nakon nitriranja u plazmi. Najveće povećanje mikrotvrdoće i najveća efektivna dubina nitriranja dobivene su na austenitnom nehrđajućem čeliku X5CrNi 18-10 nitriranjem u plazmi na 500 °C 14 h. Nije uočeno precipitiranje nitrida i karbida koji ozbiljno umanjuju otpornost na koroziju kod čelika. Za bolji uvid u korozijska i tribološka svojstva nakon nitriranja u plazmi predlaže se provedba ispitivanja korozijskih svojstava i trošenja.

Abstract (english)

The thesis considers the effect of plasma nitriding parameters on the hardness and depth of the nitrided layer in stainless steels. Previous research of plasma nitriding process on stainless steels is reviewed. The influence of parameters of nitriding on austenitic and martensitic stainless steel was investigated. Microhardness on the surface and on the cross-section was examined, surface roughness was measured and analysis of the microstructure of the nitrided layer and the core of the material were performed by light microscopy. From conducted tests a set of optimal parameters for plasma nitriding was obtained to achieve high surface hardness and optimal nitriding depth on stainless steels for structural applications. An increase in surface microhardness was observed after plasma nitriding in all test samples. The greatest increase in microhardness and the greatest effective nitriding depth were obtained on austenitic stainless steel X5CrNi 18-10 by nitriding in plasma at 500 °C for 14 h. No precipitation of nitrides and carbides, which seriously reduce the corrosion resistance of steels, was observed. For a better insight into the corrosion and tribological properties after plasma nitriding, it is proposed to perform tests of corrosion properties and wear.

• Keywords: nitriranje u plazmi; martenzitni nehrđajući čelik; austenitni nehrđajući čelik
• Keywords (english): plasma nitriding; martensintic stainless steel; austenitic stainless steel
• Language: croatian
• URN:NBN: urn:nbn:hr:235:513441
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-12-01 17:44:47