Weldability of a Cast Ni-based Superalloy
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Superalloys are known for its superior properties at higher temperature and in corrosive environment. These materials are developed for the hot part of an aero engine where other material is not suitable.
In present work, the weldability of cast alloy 718 is investigated by using Varestraint test method and compared with repair welding. Cracks which appear after welding are counted and measured by using a florescent penetrant fluid which is attached on the cracking area to identify the cracks. Different radii are used from 20 mm up to 200 mm to create different augmented strain on the samples. Repair welding is done on cast staircases with different thickness. All the cross sections are examined by using optical microscopy scanning through the heat affected zone. The amount of cracks from repair welding is compared with the results from the Varestraint test to evaluate the weldability of cast alloy 718.
Two different hot isostatic pressing (HIP) treatment and As cast condition of alloy 718 is compared. The results are presented and showed that for Varestraint test, no clear ranking could be determined. While for repair welding, the result showed clearly that As cast is outstanding when it comes to repairability.
Place, publisher, year, edition, pages
2013. , 31 p.
Welding, Weldability, Nickel, Superalloys
Other Materials Engineering
IdentifiersURN: urn:nbn:se:kth:diva-132357OAI: oai:DiVA.org:kth-132357DiVA: diva2:659553
Master of Science in Engineering - Materials Design and Engineering
Andersson, Joel, Dr
Eliasson, Anders, Dr