Abstract:
A hot press formed product being improved in corrosion resistance and in the adhesion of a coating film, which is produced by subjecting a zinc-based metal plated steel product to a hot press forming, and has a zinc-based metal plating layer containing and, formed thereon, a zinc oxide layer, wherein the uppermost zinc oxide layer has an average thickness of 2 mum or less; and a hot press formed product being excellent in corrosion resistance, the adhesion of a coating film, the resistance to corrosion after coating, and weldability, which has a basis steel plate (1) and, formed thereon, a layer (2) consisting essentially of an iron-zinc solid solution phase and, as the uppermost layer, a zinc oxide layer (3) having an average thickness of 5 mum or less, and has substantially no iron-zinc intermetallic compound phase, wherein the iron-zinc solid solution layer (2) and the zinc oxide layer (3) contain Al in a total amount of 0.5 g/m or less and/or contain Al oxides in a total amount of 5 mg/m or less in terms of Al.
Abstract:
A pin-box type threaded joint for steel tubes having a contact surface (30) including a threaded portion and a nonthreaded metal-to-metal contact portion has improved leak resistance, galling resistance, and corrosion resistance particularly to crevice corrosion. The contact surface of at least one of the pin and the box is coated with a first plating layer (34) made of a Cu-Zn alloy or a Cu-Zn-M1 alloy (wherein M1 is at least one element selected from Sn, Bi, and In). Optionally, an undercoat (32) of one or both of a Ni plating layer (32a) and a Cu plating layer (32b) and an overcoat of a Sn-M2 alloy plating layer (36) (wherein M2 is one or more elements selected from Bi, In, Ni, Zn, and Cu) may be formed below and above the first layer, respectively. A solid lubricating coating (38a) and a viscous liquid or semisolid lubricating coating (38b) may also be formed atop the plating layer as a lubricating coating (38).
Abstract:
A joint for used in connecting oil well casing and/or tubing and method of producing same are disclosed. The joint with improved metal-to-metal sealing properties as well as improved resistance to galling is made of an alloy steel containing 10% or more by weight of Cr and comprises a metal sealing portion and a threaded portion provided with an activating layer of a metal or an alloy selected iron, nickel, zinc, cobalt, copper, manganese, chromium and alloys thereof, and an electrodeposited layer of a metal or an alloy selected from iron, copper, zinc, chromium, nickel, and alloys thereof.
Abstract:
A joint for used in connecting oil well casing and/or tubing and method of producing same are disclosed. The joint with improved metal-to-metal sealing properties as well as improved resistance to galling is made of an alloy steel containing 10% or more by weight of Cr and comprises a metal sealing portion and a threaded portion provided with an activating layer of a metal or an alloy selected iron, nickel, zinc, cobalt, copper, manganese, chromium and alloys thereof, and an electrodeposited layer of a metal or an alloy selected from iron, copper, zinc, chromium, nickel, and alloys thereof.
Abstract:
A hot press-formed article having improved corrosion resistance and coating adhesion when coated is obtained by hot press forming of a zinc-based plated steel material. It has a zinc-based plating layer comprising an iron-zinc solid solution phase and atop it a zinc oxide layer. The average thickness of the zinc oxide layer which is the outermost layer is at most 2 µm. A hot press-formed article having a good appearance and excellent corrosion resistance, coating adhesion, post-coating corrosion resistance, and weldability has a layer (2) consisting essentially of an iron-zinc solid solution phase atop a base material steel sheet (1). It also has a zinc oxide layer (3) with an average thickness of at most 5 µm as an uppermost layer, but it does not have a substantial amount of an iron-zinc intermetallic compound phase. The total amount of Al contained in the iron-zinc solid solution layer (2) and the zinc oxide layer (3) is at most 0.5 g/m 2 , and/or the total amount of Al oxides contained in these layers is at most 5 mg/m 2 .
Abstract:
A joint for used in connecting oil well casing and/or tubing and method of producing same are disclosed. The joint with improved metal-to-metal sealing properties as well as improved resistance to galling is made of an alloy steel containing 10% or more by weight of Cr and comprises a metal sealing portion and a threaded portion provided with an activating layer of a metal or an alloy selected iron, nickel, zinc, cobalt, copper, manganese, chromium and alloys thereof, and an electrodeposited layer of a metal or an alloy selected from iron, copper, zinc, chromium, nickel, and alloys thereof.
Abstract:
A screw joint for steel pipe of pin/box type having contact surfaces (30) including a threaded part and an unthreaded metal contact part is improved with respect to the leakage resistance, galling resistance and corrosion res istance, especially that to crevice corrosion. The contact surface of at lea st one of the pin and the box is covered with a first plating layer (34) of Cu-Zn alloy or Cu-Zn-M1 alloy (M1 is at least one selected from among Sn, Bi and In). The first plating layer on its downside and upside may be provided with a lower layer (32) consisting of Ni plating layer (32a) and/or Cu plat ing layer (32b) (one or both of the layers) and an upper layer of Sn-M2 allo y (M2 is at least one element selected from among Bi, In, Ni, Zn and Cu) pla ting layer (36). The plating layers may be overlaid with a lubricant coating (38) selected from among a solid lubricant coating (38a) and a viscous liqu id or semisolid lubricant coating (38b).