Effects of Heat Input on Weld Microstructure and Properties in Keyhole TIG Welding of Invar 36 Alloy

Hongbing Liu, Shanhui Lv, Yang Xuan, João Pedro Oliveira, Norbert Schell, Jiajia Shen, Jingyu Deng, Yuhua Wang, Jin Yang

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)
8 Downloads (Pure)

Abstract

The Invar alloy is widely used for aircraft wing mould manufacturing. In this work, keyhole-tungsten inert gas (K-TIG) butt welding was used to join 10 mm thick Invar 36 alloy plates. The effect of heat input on the microstructure, morphology and mechanical properties was studied by using scanning electron microscopy, high energy synchrotron X-ray diffraction, microhardness mapping, tensile and impact testing. It was shown that regardless of the selected heat input, the material was solely composed of austenite, although the grain size changed significantly. The change in heat input also led to texture changes in the fusion zone, as qualitatively determined with synchrotron radiation. With increases in heat input, the impact properties of the welded joints decreased. The coefficient of thermal expansion of the joints was measured, which demonstrated that the current process is suitable for aerospace applications.

Original languageEnglish
Article number3692
Number of pages15
JournalMaterials
Volume16
Issue number10
DOIs
Publication statusPublished - 12 May 2023

Keywords

  • heat input
  • Invar 36 alloy
  • K-TIG welding
  • mechanical properties
  • synchrotron X-ray diffraction

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