Effects of PWHT on the microstructure and mechanical properties of ERNiCrFe-7 all-weld metal
2015 (English)In: Welding in the World, ISSN 0043-2288, Vol. 59, no 3, 317-323 p.Article in journal (Refereed) Published
The effects on the microstructure and room temperature mechanical properties of the nickel-based filler metal ERNiCrFe-7 due to a post weld heat treatment (PWHT) at 610 °C have been studied. It was shown that PWHT caused an increase in yield strength and ultimate tensile strength, but at the cost of reduced ductility and impact toughness. Crack tip opening displacement (CTOD) fracture toughness tests revealed an initial increase in maximum CTOD when a short PWHT was given, but declined with prolonged PWHT. The PWHT also caused a transition in fracture mechanism from microvoid coalescence to quasi-cleavage in room temperature air. Chromium-rich M<inf>23</inf>C<inf>6</inf> type grain boundary carbides were present already in the as-welded weld metal, and were observed to coarsen during the PWHT. Intragranular M<inf>23</inf>C<inf>6</inf> carbides were not observed in the as-welded state, but were precipitated during the 610 °C PWHT. Precipitation of these intragranular carbides is believed to be the main reason for the changes in mechanical properties.
Place, publisher, year, edition, pages
2015. Vol. 59, no 3, 317-323 p.
Heat treatment, Nickel, Strength, Toughness, Carbides, Crack tips, Filler metals, Fracture, Grain boundaries, Mechanical properties, Microstructure, Tensile strength, Welding, Welds, Crack tip opening displacement, Fracture toughness tests, Grain boundary carbides, Microstructure and mechanical properties, Nickel-based filler metal, Post weld heat treatment, Ultimate tensile strength, Fracture toughness
IdentifiersURN: urn:nbn:se:kth:diva-167748DOI: 10.1007/s40194-014-0201-4ISI: 000354742900001ScopusID: 2-s2.0-84928233485OAI: oai:DiVA.org:kth-167748DiVA: diva2:815519
QC 201506012015-06-012015-05-222015-06-15Bibliographically approved