Greške u mikrostrukturi debelostijenih odljevaka od feritnog nodularnog lijevakvalitete HRN-EN-GJS-400-18-LT za vjetroagregate

undergraduate thesis

• Title (english): Defects in microstructure of heavy section HRN-EN-GJS-400-18-LT ferritic ductile iron windmill castings
• Author: Ivana Bunjan
• Mentor: Zoran Glavaš (mentor)
• Committee member: Martina Lovrenić - Jugović (predsjednik povjerenstva)
• Committee member: Zoran Glavaš (član povjerenstva)
• Committee member: Stjepan Kožuh (član povjerenstva)
• Granter: University of Zagreb; Faculty of Metallurgy; Sisak
• Defense date and country: 2016-07-18, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Metallurgy; Process Metallurgy

Abstract

Feritni nodularni lijev kvalitete HRN-EN-GJS-400-18-LT je pogodan materijal za mnoge masivne komponente vjetroagregata. Budući da se broj instaliranih vjetroagregata konstantno povećava, potražnja za debelostijenim odljevcima od feritnog nodularnog lijeva također raste.
Konzistentno postizanje zahtijevane kombinacije vlačne čvrstoće, granice razvlačenja, istezanja i žilavosti pri niskim temperaturama u debelostijenim odljevcima od feritnog nodularnog lijeva kvalitete HRN-EN-GJS-400-18-LT je vrlo zahtjevan zadatak. Da bi se ispunili ti zahtjevi, vrlo je važno ostvariti odgovarajuće mikrostrukturne značajke te izbjeći, odnosno minimalizirati greške u mikrostrukturi. Niska nodularnost, tj. prisutnost nepravilno oblikovanih grafitnih nodula i nesferičnih grafitnih čestica, kao što su „chunky“, eksplodirani, „spiky“, vermikularni i listićavi grafit, flotacija grafita, perlit, uključci troske i krhke faze na granicama zrna onemogućuju postizanje zahtijevanih mehaničkih svojstava. Ovaj rad daje pregled uzroka tih grešaka i mjera za eliminaciju ili smanjenje njihovog nastajanja.

Abstract (english)

Ferritic ductile iron grade HRN-EN-GJS-400-18-LT is a suitable material for many massive windmill parts. The number of installed windmills grows from year to year. Therefore, the demand for heavy section ferritic ductile iron castings grows.
Consistently achieving the required combination of tensile and yield strength, elongation and low temperature impact strength in heavy section ferritic ductile iron grade HRN-EN-GJS-400-18-LT is very demanding task. To fulfill these requirements, it is very important to achieve proper microstructural features and avoid or minimize the defects in the microstructure. Low nodularity, i.e. the presence of irregularly shaped graphite spheroids and non-spheroidal graphite forms, such as chunky, exploded, spiky, vermicular and flake graphite, graphite floatation, pearlite, dross, brittle phases at grain boundaries prevent the achievement of the required mechanical properties. This paper presents the causes of these defects and remedies to eliminate/limit their formation.

• Keywords: nodularni lijev; mikrostruktura; ljevarske greške
• Keywords (english): ductile iron; microstructure; casting defects
• Language: croatian
• URN:NBN: urn:nbn:hr:115:726882
• Study programme: Title: Metallurgy; specializations in: Metallurgical Engineering, Industrial Ecology; Course: Metallurgical Engineering; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka metalurgije (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka metalurgije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2016-10-03 07:46:47