Composite electrode for a plasma arc torch

A composite electrode for use in a plasma arc torch comprising:

• a body defining a bore and a cooling area which receives a coolant, the body comprising a forward port ion, an aft port ion, and a forged weld joint;
• the forward port ion of the body comprising a first material with a heat transfer property, the forward portion including a first mating surface;
• the aft port ion of the body comprising a second material different from the first material, the heat transfer property of the second material is different than the heat transfer property of the first material, the aft portion including a second mating surface;
• and
• the forged weld joint disposed between the forward and aft portions along the first and second mating surfaces to provide direct metallurgical coupling along the forged weld joint, the forged weld joint having a bend test strength and a tensile test strength equal to that of the first material;
• and
• an emissive element disposed within the bore and in thermal contact with the forward portion.

A method of forming an electrode for a plasma arc torch, the method comprising:

• utilizing a combination of physical force and acceleration and deceleration of a forward portion comprising a first metallic material with a heat transfer property and an aft portion comprising a second metallic material with the heat transfer property of the second metallic material being different than the heat transfer property of the first metallic material to form an electrode body including a hermetic joint providing direct metallurgical coupling between the forward and aft port ions along the hermetic joint;
• forming a bore within the forward port ion to surround at least a port ion of an emissive insert;
• and
• inserting the emissive insert into the bore to provide thermal contact between the emissive insert and the forward portion.

A composite electrode for use in a plasma arc torch, the composite electrode manufactured by a method comprising:

• providing an aft portion of an electrode body comprising a first metallic material and having a first mating surface;
• providing a forward portion of the electrode body comprising a second metallic material and having a second mating surface configured to join with the first mating surface, wherein the first and second metallic materials have a heat transfer property, the value of the heat transfer property for the second metallic material being greater than that of the first metallic material;
• and
• directly welding the first and the second mating surfaces to form a joint, wherein directly welding is a process selected from the group consisting of friction welding, inertia friction welding, direct drive friction welding, CD percussive welding, percussive welding, ultrasonic welding and explosion welding.