Short circuit pipe welding
AssigneeLincoln Global, Inc.
InventorElliott K. Stava
Life of this patent
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Abstract
An apparatus and method of short circuiting arc welding two spaced ends of two pipe sections at a groove between the two pipe sections. The method and apparatus include the use of a cored metal electrode and moving the electrode toward the groove as the electrode is moved along the groove and about the outer peripheral surface of the pipe sections during the welding operation. The cored electrode is melted by an electric wave which comprises a transfer portion and a controlled melting portion. The melting portion is controlled to bridge the gap between the pipe sections for laying a root bead along the groove. The cored electrode is preferably a self-shielding electrode and includes alloying components in the core to form a root bead having a substantially similar composition as the composition of the two pipe sections.
Claims94
A method of short circuiting arc welding two spaced ends of two pipe sections at a groove between said two sections and defining a gap, said method comprising the steps of:
- a) providing a flux cored metal electrode in a supply reel;
- b) positioning the ends of said plates together to form an elongated channel between said ends to define an gap:
- c) moving said electrode toward said groove as said electrode is moved along said groove;
- d) melting said electrode by an electric wave comprising a short circuit transfer portion and a controlled melting portion, said controlled melting portion selected from the group consisting of applying a preselected amount of energy to the electrode or applying a preselected amount of power to said electrode;
- and
- e) controlling said melting portion of said electric wave to bridge said gap between said pipe sections for laying a root bead along said groove.
An apparatus for short circuiting arc welding two spaced ends of two pipe sections at a groove between said two sections and defining a gap which comprises:
- a) a welding carriage positioned around and closely adjacent to said groove;
- b) a flux cored metal electrode positioned on said welding carriage and being controllably moved toward said groove;
- c) a welding current circuit that supplies current to said electrode, said welding circuit including a first circuit to create a transfer current and a second circuit to create a melting current, said second circuit supplying a sufficient amount of current to said electrode to form a root bead in said groove which bridges said gap.
A method of short circuiting arc welding together two steel plates from one side of said plates, said method comprising the steps of:
- a) providing a flux cored metal electrode in a supply reel;
- b) positioning the ends of said plates together to form an elongated channel between said ends to define an gap;
- b) moving said electrode toward said elongated channel as said electrode is moved along said elongated channel;
- c) melting said electrode by an electric wave comprising a short circuit transfer portion and a controlled melting portion, said controlled melting portion selected from the group consisting of applying a preselected amount of energy to the electrode or applying a preselected amount of power to said electrode;
- and
- d) controlling said melting portion of said electric wave to bridge said gap between said plates for laying a weld bead along said elongated channel.
A method of short circuiting arc welding together two metal plates from one side of said plates, said method comprising the steps of:
- a) providing a flux cored metal electrode in a supply reel;
- b) positioning the ends of said plates together to form an elongated channel between said ends to define an gap;
- b) moving said electrode toward said elongated channel as said electrode is moved along said elongated channel;
- c) melting said electrode by an electric wave comprising a transfer portion and a controlled melting portion;
- d) controlling said melting portion of said electric wave to bridge said gap between said plates for laying a weld bead along said elongated channel;
- and
- e) controlling the polarity of said electric wave during the laying of said weld bead.
An apparatus for short circuiting arc welding two spaced ends of two metal plates at a groove between said two metal plates and defining a gap which comprises:
- a) a welding carriage positioned around and closely adjacent to said groove;
- b) a flux cored metal electrode positioned on said welding carriage and being controllably moved toward said groove;
- c) a welding current circuit that supplies current to said electrode, said welding circuit including a first circuit to create a transfer current, a second circuit to create a melting current to supply a sufficient amount of current to said electrode to form a root bead in said groove which bridges said gap, and a polarity controller to control the polarity of at least a portion of said current.
Dependencies are inferred from the claim text.