Threaded joint for steel pipes
AssigneesSumitomo Metal Industries, Ltd., Vallourec Mannesmann Oil & Gas France
InventorsShigeo Nagasaku, Kunio Goto, Shigeo Onishi, Hiroaki Ikegami
Life of this patent
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Abstract
A threaded joint for steel pipes comprised of a pin (1) and a box (2) each having a threaded portion (1a, 2b) and an unthreaded contact portion (1b, 2a) exhibits adequate leakage resistance and galling resistance when used for makeup of oil country tubular goods with application of a green dope or even without any dope. The threaded joint has a first plating layer of Sn—Bi—Cu alloy plating formed on the contact surface of at least one of the pin (1) or the box (2). The first plating layer may have a second plating layer selected from Sn plating, Cu plating, and Ni plating on its lower side and at least one layer of a lubricating coating, and particularly a solid lubricating coating on its upper side.
Claims8
A pin of a threaded joint for steel pipes having a contact surface including a threaded portion and an unthreaded metal contact portion, characterized by having a first plating layer as an Sn—Bi—Cu alloy plating layer formed on at least a part of the contact surface and having a second plating layer formed beneath the first plating layer, the second plating layer being an electroplating layer selected from the group consisting of Sn plating, Cu plating, and Ni plating.
A box of a threaded joint for steel pipes having a contact surface including a threaded portion and an unthreaded metal contact portion, characterized by having a first plating layer as an Sn—Bi—Cu alloy plating layer formed on at least a part of the contact surface and having a second plating layer formed beneath the first plating layer, the second plating layer being an electroplating layer selected from the group consisting of Sn plating, Cu plating, and Ni plating.
A threaded joint for steel pipes comprised of a pin and a box each having a contact surface including a threaded portion and an unthreaded metal contact portion, characterized by having a first plating layer as an Sn—Bi—Cu alloy plating formed on at least a part of the contact surface of at least one of the pin and the box, and further having a second electroplating layer selected from the group consisting of Sn plating, Cu plating, and Ni plating beneath the first plating layer.
Dependencies are inferred from the claim text.