Electron beam welding of two dissimilar metals

Claim 2

A welding method for the reduction of the brittle intermetallic phase normally produced in a welded seam between two dissimilar metals which phase adversely affects the stability of the welded joint, comprising applying a beam of charged particles to cause fusion in the area of the weld and controlling the application of the same, the welding parameters being controlled according to the following equation: wherein: I beam current in Amp., Lp period length in milliseconds, Li impulse length in milliseconds, keying ratio, U acceleration voltage in volt, and v welding velocity in cm/sec, and the position of the line of impingement of said beam being in the range of 0.07 to 0.2 mm. away from the center of the joint, such that there is a constant concentration of the metal components over a major portion of the width of the weld which is substantially different from the normal concentration thereof in said intermetallic phase, but intermediate of the concentrations thereof in each of said two dissimilar metals, whereby the zone of said intermetallic phase is relatively quite small and the concentration change of the metal components therein is quite precipitous.

Claim 3

In the welding of two dissimilar metals each of which in the area of welding has an initial thickness less than about 5 mm., said two dissimilar metals with respect to a single pure metal component having substantially different amounts of said metal component and said welding being effected by progressively heating and fusing of the joint along the line of weld by impingement thereon of an electron beam, the improvement resulting in a minimization of the zone of the phase change across which the concentration of said pure metallic component changes from the higher value as it exists in one of said two dissimilar metals to the lower value as it exists in the other, comprising: impinging said electron beam along a line parallel to the center line of said weld and spaced in the range of 0.07 to 0.2 mm. therefrom, and controlling the energy introduced into said weld according to: wherein: I beam current in Amp., Lp period length in milliseconds, Li impulse length in milliseconds, U beam voltage in volts, and v welding velocity in cm/sec.; the completed weld having, with respect to said pure metal component, a substantially constant concentration thereof intermediate of the concentration thereof in each of said dissimilar metals, across substantially the entire width of the zone of fusion of the metal with said zone of phase change being at the edge thereof within which said substantially constant concentration changes precipitously to equal the concentration of said pure metal component in one of said two dissimilar metals, and said completed weld having a hardness value at any intermediate point in said zone of fusion that does not exceed the hardness values of either of said two dissimilar metals.

Claim 4

In the welding of two dissimilar metals each of which in the area of welding has an initial thickness less than about 5 mm., said two dissimilar metals with respect to a single pure metal component having substantially different amounts of said metal component and said welding being effected by progressively heating and fusing of the joint along the line of weld by impingement thereon of an electron beam, the improvement resulting in a minimization of the zone of the phase change across which the concentration of said pure metallic component changes from the higher value as it exists in one of said two dissimilar metals to the lower value as it exists in the other, comprising: impinging said electron beam along a line parallel to the center line of said weld and spaced in the range of 0.07 to 0.2 mm. therefrom, and controlling the energy introduced into said weld according to: wherein: I beam current in Amp., Lp period length in milliseconds, Li impulse length in milliseconds, U beam voltage in volts, and v welding velocity in cm/sec.; the completed weld having, with respect to said pure metal component, a substantially constant concentration thereof intermediate of the concentration thereof in each of said dissimilar metals, across substantially the entire width of the zone of fusion of the metal with said zone of phase change being at the edge thereof within which said substantially constant concentration changes precipitously to equal the concentration of said pure metal component in one of said two dissimilar metals, and said completed weld having a hardness value at any intermediate point in said zone of fusion that does not exceed the hardness values of either of said two dissimilar metals.