Method of welding

A method of producing a weld joint that will not crack during a weld solidification process, said method comprising the steps of:

• abutting generally corresponding surfaces defined by two metal pieces to be welded;
• applying a power beam simultaneously against said metal pieces with an intensity sufficient to cause metal adjacent a predetermined portion of each abutting surface to become molten thereby producing said weld joint from the coalescence of metals;
• limiting the root depth of said weld joint;
• and
• providing a stress relief groove on one of said metal pieces, said groove being spaced from said weld joint to define a relatively narrow ligament immediately adjacent to the molten metal producing said weld joint, and wherein said ligament is configured with a length extending parallel to the direction of power beam application and equal to about two times the depth of the weld joint and a width equal to about the depth of the weld joint such that said ligament is permitted to flex and thereby minimize stresses on the weld joint during weld solidification thereby inhibiting shrinkage related cracking of the weld joint.

A method of inhibiting cracking of a continuous circular weld joint between a metal shaft and a metal member joined to said shaft by said weld joint, said method comprising the steps of:

• producing said circular weld joint from a coalescence of molten metals obtained by applying a concentrated coherent light beam upon adjacent and generally corresponding surfaces defined by said shaft and said member;
• and
• providing a relatively narrow annular ligament extending from one of said shaft and said metal member and including at least a portion of a boundary region of said circular weld joint and configured with a length extending parallel to the direction of light beam application and measuring approximately two times the depth of the weld joint and with a width measuring approximately the depth of the weld joint, and wherein the annular ligament is designed to flex thereby allowing weld joint volume to transmute and minimize stresses during weld solidification thereby inhibiting shrinkage related cracking of the weld joint;
• and
• limiting the root depth of said circular weld joint to less than the distance said annular ligament extends from one of said shaft and said metal member.

A method for inhibiting cracking of a circular weld joint comprising the steps of:

• producing said circular weld joint from a coalescence of molten metals obtained by applying a concentrated coherent light beam upon adjacent and generally corresponding surfaces defined by a shaft and a member;
• and
• providing a relatively narrow annular ligament extending from one of said shaft and said metal member and including at least a portion of a boundary region of said circular weld joint and configured to flex thereby allowing said weld joint volume to transmute and minimize stresses during weld solidification thereby inhibiting shrinkage related cracking of the weld joint;
• limiting the root depth of said circular weld joint to less than the distance said annular ligament extends from one of said shaft and said metal member;
• and
• ramping down the application of said light beam upon said adjacent surfaces after turning said shaft and said member 360 degrees.

A method for inhibiting shrinkage related cracking of a weld joint provided between two carburized metal pieces, said method comprising the steps of:

• providing noncarburized surface areas on abutting areas of the metal pieces where the weld joint is formed;
• directing a laser beam toward and along a line defined by the abutting areas on said metal pieces with an intensity sufficient to cause metal on both pieces to become molten thereby producing said weld joint from the coalescence of metals;
• providing an elongated slot below the weld joint and extending from one of the abutting surfaces to limit the depth of the weld joint;
• and
• providing a relatively narrow ligament on at least one of said metal pieces to retard solidification of the weld joint through retention of heat therein, said ligament extending from said one of said metal pieces and includes at least a portion of a boundary region of said molten metals forming the weld joint, and wherein the ligament provided is specifically sized with a length extending from at least one of the metal pieces parallel to the direction of the laser beam for a distance approximately twice the depth of the weld joint and has a width approximately the depth of the weld joint such that the ligament flexes and whereby reduces constraints on the weld joint during weld solidification thereby inhibiting shrinkage cracking of the weld joint.