The influence of electron-beam welding parameters on heat-affected-zone microfissuring in INCOLOY 903

Journal Article · Mon Aug 01 04:00:00 EDT 1994 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

DOI:https://doi.org/10.1007/BF02668538· OSTI ID:7167301

Richards, N L ^[1]; Nakkalil, R; Chaturvedi, M C ^[2]

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1. Bristol Aerospace Ltd., Winnipeg, Manitoba (Canada). Test and Development Lab.
2. Univ. of Manitoba, Winnipeg (Canada). Dept. of Mechanical and Industrial Engineering

The microfissuring in the heat-affected zone (HAZ) of electron-beam- (EB-) welded thermomechanically processed INCOLOY 903 has been studied with a view to reducing the incidence of microfissuring and to obtaining a better understanding of the influence of EB welding parameters on it. For a given heat of material, microfissuring susceptibility has been quantitatively related to EB welding parameters and the shape of the weld pool. Fractional factorial experimental study of welding parameters showed that a reduction in welding speed and an increase in EB current for a given heat input would minimize HAZ microfissuring in the alloy. It was observed that with lower travel speeds, because of the shallower temperature gradients in the HAZ, the amount of liquated grain boundary area is less, thus leading to decreased microfissuring. Considerable HAZ microfissuring was observe on the coarse grain boundaries of warm-worked grains. The microfissures appeared to initiate in regions slightly removed from the fusion line. Minimal microfissuring was observed on the grain boundaries of fine recrystallized grains. These boundaries, however, had a thickened appearance because of the formation of Nb-enriched [gamma] phase by the process of grain boundary liquid film migration (LFM). The origin of the liquid on the grain boundaries is suggested to be due to the constitutional liquation of preexisting primary carbides (partial), fine MC carbides, and MNP-type phosphides.

• OSTI ID: 7167301
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Journal Name: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States) Vol. 25:8; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
CRACK PROPAGATION
ELECTRON BEAM WELDING
EXPANSION
FABRICATION
HEAT AFFECTED ZONE
INCOLOY ALLOYS
JOINING
PHASE TRANSFORMATIONS
SOLIDIFICATION
THERMAL EXPANSION
WELDING
ZONES