Electric Power Research Institute Incorporated

Wylie J Childs

Shane J Findlan

Gregory J Frederick

Artie Gene Peterson, Jr

J Darryl Baucom

Artie G Peterson

A laser beam welding technique which can be utilized to accomplish clad welding and repair of the internal surface of a tube. The technique uses the addition of filler metal to build up the internal surface of the tube. The apparatus includes a laser energy source connected to an elongated weld head by an optical fiber. The elongated weld head is rotatable and contains a mirror canted at a forty-five (45) degree angle. The laser beam generated by the laser source enters the weld head through a rotary joint, passes through focusing lenses, and is reflected to the interior surface of the damaged tube by the canted mirror. Apparatus rotates the weld head which causes the beam to travel circumferentially around the interior of the tube. Metal fill material is fed to the location where the focused beam contacts the interior surface of the tube. The result is a smooth clad welding repair on the inside surface of the tube which restores the strength of the tube and leaves no crevices for future corrosion attack. In addition, the internal diameter of the tube is very close to the original diameter of the tube thus obviating pressure drop associated with the sleeving type repair and allowing for subsequent repair of the tube at positions beyond the first area of repair.

Method and apparatus for repairing damaged tubes by interior laser clad

A laser welding apparatus for clad welding the interior surface of a tube includes a rotating sleeve that encloses a fiber optic cable. A stationary laser generates light energy for the welding operations performed by the rotating sleeve. An optical coupler is positioned between the stationary laser and the rotating sleeve. A fixed optical assembly of the optical coupler receives light energy from the stationary laser and produces collimated and focused light energy. A rotating cable interface assembly of the optical coupler receives the collimated and focused light energy from the fixed optical assembly and applies it to the fiber optic cable of the rotating sleeve, which delivers the light energy to the interior surface of a tube so that it may be used to produce a clad weld. The fixed optical assembly includes axial and concentric alignment devices. The rotating cable interface assembly includes concentric alignment means and a monitoring cavity to provide optical feedback regarding the alignment between the fixed optical assembly and the rotating cable interface assembly. The rotating cable interface assembly may be constructed to include a safety fiber optic with an accompanying safety fiber optic photocell which is used to assess whether excessive light energy from the laser is being used.

Rotating fiber optic coupler for high power laser welding applications

A method of forming a clad weld on the interior surface of a tube includes the step of delivering a rotating filler metal wire to a selected weld location on the interior surface of the tube. The filler metal wire is synchronously rotated with a fiber optic cable which directs laser energy to the selected weld location. This results in the fusing of the filler metal wire to the interior surface of the tube to produce a clad weld within the tube.

Method of forming a clad weld on the interior surface of a tube with a

A laser welding apparatus for clad welding the interior surface of a tube is disclosed. The apparatus includes a rotating sleeve positionable within the tube. Located within the rotating sleeve is a fiber optic cable and a filler passage. The fiber optic cable receives laser energy from a laser. The filler passage receives filler material from a filler metal delivery system that synchronously moves with the rotating sleeve. Positioned at the end of the rotating sleeve is a welding head which includes a head aperture and a laser energy directional modification assembly. The laser energy from the fiber optic cable is transferred through the laser energy directional modification assembly and through the head aperture to a selected weld location on the interior surface of the tube. The filler metal from the filler metal delivery system is also conveyed through the head aperture and intersects with the laser energy at the selected weld location. The filler metal fuses with the interior surface of the tube to produce a clad weld.

Rotating apparatus for repairing damaged tubes

Disclosed is a laser beam welding technique which can be utilized to accomplish clad welding and repair of the internal surface of a tube. The technique uses the addition of filler metal to build up the internal surface of the tube. The apparatus includes a laser energy source connected to an elongated weld head by an optical fiber. The elongated weld head is rotatable and contains a mirror canted at a forty-five (45) degree angle. The laser beam generated by the laser source enters the weld head through a rotary joint, passes through focusing lenses, and is reflected to the interior surface of the damaged tube by the canted mirror. Means are provided to rotate the weld head which causes the beam to travel circumferentially around the interior of the tube. Means are also provided to feed metal fill material to the location where the focused beam contacts the interior surface of the tube. The result is a smooth clad welding repair on the inside surface of the tube which restores the strength of the tube and leaves no crevices for future corrosion attack. In addition, the internal diameter of the tube is very close to the original diameter of the tube thus obviating pressure drop associated with the sleeving type repair and allowing for subsequent repair of the tube at positions beyond the first area of repair.

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Belmont, CA, United States of America

Wylie J Childs