Showing papers on "Liquation published in 1980"
TL;DR: A review of the classification, identification and mechanisms of liquation cracking can be found in this paper, where compositional influences in austenitic stainless steels and nickel alloys are considered in more detail.
Abstract: Liquation cracking can occur during fabrication by welding in either the heat affected zone in the parent material, or in previously deposited weld metal during a subsequent run. It results from localized melting at grain or other boundaries, combined with the thermal strains associated with welding. This review paper opens with brief descriptions of the classification, identification and mechanisms of liquation cracking. Following an outline of the material classes and circumstances in which it is most likely to occur, compositional influences in austenitic stainless steels and nickel alloys are considered in more detail. It is emphasized that although residual elements such as S, P or B may have an important role in causing or enhancing liquation effects, much liquation cracking is associated with intentional minor alloying additions, such as Nb. The influence of deliberate alloying additions, and compositional balance, in limiting the influence of residuals will be considered. In conclusion the detection, significance and avoidance of liquation cracking are discussed briefly.
42 citations
TL;DR: In this article, an electron-beam welding process showed greater promise of success in welding these alloys, in particular Ir 0·3W doped with 200ppm Th and 50ppm Al.
Abstract: Modified iridium alloys containing ≥ 100ppm Th were found to be very susceptible to cracking during gas tungsten-arc and electron-beam welding. However, the electron-beam welding process showed greater promise of success in welding these alloys, in particular Ir–0·3W doped with 200ppm Th and 50ppm Al. The weld ability of this particular alloy was extremely sensitive to the welding parameters, such as beam-focus condition and welding speed, and the resulting fusion-zone structure. At low speeds successful electron-beam welds were made over a narrow range of beam-focus conditions. However, at high speeds successful welds can be made over an extended range of focus conditions. The fusion-zone grain structure is also a strong function of welding speed and focus condition. Weld-metal cracking was found to be caused by the combined effects of heat-affected-zone liquation cracking and solidification cracking. Scanning electron microscopic analysis of the fractured surface revealed patches of low-melting...
16 citations