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AssigneeHitachi, Ltd.
InventorsTomio Umino, Munenobu Suzuki, Tomohiko Shida
Estimating the term…
In a process for fusion-welding a binary combination of an iron alloy containing 50 % by weight or less of nickel and cobalt combined and copper; or a ternary combination of said iron alloy, copper, and iron, including the steps of bringing members of said binary combination or ternary combination into gapless contact with one another and subjecting the contact zone to a treatment including at least one of electron beam welding, laser beam welding, plasma welding, and TIG welding without use of a filler metal, an improvement which is characterized by supplying welding energy necessary to form in the welding zone molten weld metal having such a width and depth that have been determined from the composition and thickness of said base metals so that the composition of the weld metal may fall within the specified area in a diagram, shown in FIG. 1, representing composition of a three component system, said specified area being enclosed with straight lines connecting successively the point X (97 wt-% Cu, 2 wt-% Fe, 1 wt-% Ni + Co), the point Y (2 wt-% Cu, 49 wt-% Fe, 49 wt-% Ni + Co), the point Z (2 wt-% Cu, 97 wt-% Fe, 1 wt-% Ni + Co), and the point X except for the area enclosed with straight lines connecting successively the point a (35 wt-% Cu, 32.5 wt-% Fe, 32.5 wt-% Ni + Co), the point b (10 wt-% Cu, 45 wt-% Fe, 45 wt-% Ni + Co), the point c (8 wt-% Cu, 91 wt-% Fe, 1 wt-% Ni + Co), the point d (45 wt-% Cu, 54 wt-% Fe, 1 wt-% Ni + Co), and the point a. According to this improved process, development of weld cracking can be prevented.
A process of fusion welding comprising the steps of
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
Fe as the principal constituent: with Ni as next major constituent
With the principal constituent melting at less than 1550°C: cu as the principal constituent
Soldering or unsoldering
Term ended 16 Mar 1993 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
1. Field of the Invention
This invention relates to a process for fusion-welding a binary combination of an iron alloy containing 50% by weight or less of nickel and cobalt combined and copper, or a ternary combination of said iron alloy, copper, and iron by bringing members of said binary or ternary combination into gapless contact with one another and subjecting the contact zone to a treatment selected from electron beam welding, laser beam welding, plasma welding, and TIG welding without use of a filler metal.
2. Description of the Prior Art
FIG. 1 is a composition diagram of a three-component system comprising copper, iron, and a mixed component of nickel and cobalt, wherein experimental results of weld cracking are plotted.
FIGS. 2a and 2b are photomicrographs of the structure of weld metals obtained by electron beam welding of iron-nickel-cobalt alloy and copper.
FIG. 3 is a sectional view of a microwave oscillator tube where the process of this invention is applied.
A binary combination of copper and an iron-nickel-cobalt alloy and a ternary combination of copper, iron, and an iron-nickel-cobalt alloy were respectively joined together by electron beam welding. In both cases, welding was carried out in such a manner that after the base metals had been placed one over another so that the iron-nickel-cobalt alloy and copper metal may occupy the uppermost position and the lowest position, respectively, an electron beam was applied to the surface of the iron-nickel-cobalt alloy to effect welding. In each case, the resulting weld metal was tested by observation with microsope for cracking and analyzed for chemical composition. Several of the results obtained were as shown in Table 1. The iron-nickel-cobalt alloy employed in this Example comprised 30 % by weight nickel, 20 % by weight cobalt, and 50 % by weight iron.
Table 1 ______________________________________ Composition of weld Combination of metal (% by weight) Cracking base metals Cu Fe Ni+Co ______________________________________ Fe-Ni-Co alloy & Cu 12.4 46.4 41.2 Occurred " 8.4 48.5 43.1 Did not occur " 52.2 25.3 22.5 Did not occur Fe-Ni-Co alloy 25.3 54.7 20.0 Occurred & Cu & Fe " 14.6 74.0 11.4 Occured " 37.1 42.8 20.1 Microcracks " 40.0 43.5 16.5 Microcracks " 59.0 24.5 16.5 Did not occur " 50.0 38.6 11.4 Did not occur ______________________________________
FIG. 1 is a composition diagram of the three-component system comprising a mixed component of nickel and cobalt, copper and iron, obtained by plotting the results obtained in this Example. In FIG. 1 white dots represent compositions which showed no weld cracking, black dots represent those which showed weld cracking, and the dots partly white and partly black represent those which showed no cracking on inspection with naked eyes but revealed micro-cracking on microscopic examination.