A threaded joint for steel pipe formed on a pin and a box having a contact surface including threaded parts and a non-threaded metal contact part and capable of stably assuring a galling resistance and an airtightness without applying compound grease threreto, wherein a solid lubricating film formed with lubricating powder (e.g., molybdenum disulfide) and organic or inorganic binder is formed on the contact surface of at least one of the pin and the box, the ratio of area occupied by the secondary particles of 15 to 60 µm in equi-area equivalent diameter of the lubricating powder in the cross section of the solid lubricating film in thickness direction is 5 to 90%, and fiber-like filler (e.g., inorganic substance whisker) in addition to the lubricating powder is mixed into the solid lubricating film at the mass ratio of the fiber-like filler to the binder of 0.01 to 0.5, whereby, particulary, the galling resistance at high temperatures can be improved.

Threaded joint for steel pipes

Effects of transformation temperature on variant pairing of bainitic ferrite in low carbon steel

A detailed qualitative and quantitative microstructural examination of four dual-phase steels has been carried out. Dual-phase structures were produced in three of these steels by intercritical annealing; the other was in the as-rolled condition. Similar combinations of tensile properties were obtained with all four steels. In intercritically annealed material, greater austenite hardenability was encountered with the two steels containing strong carbide-forming elements (vanadium or titanium) than with a similar plain carbon steel. It has therefore been proposed that the carbonitride precipitates (which are present during the anneal) inhibit the movement of the austenite/ferrite interface during the post-anneal quench; strong metallographic evidence has been provided to support this view. It has been found that during tensile deformation, martensite islands do not deform until strains well in excess of the maximum uniform strain have been reached; this observation has enabled the successful applic...

Work hardening of dual-phase steels

Vanadium as an important alloying element in steels was initially associated with the properties achieved following tempering. Interest in the microstructure was stimulated by the advent of transmission electron microscopes with a resolution of ∼1 nm together with selected area electron diffraction techniques. A second timely development was that of controlled rolling, particularly of plate and sheet products. The scope of this review will include the historical background on quenched and tempered vanadium steels, precipitation during isothermal aging, conventional controlled rolling and during thin slab direct charging and the development of strength and toughness in vanadium microalloyed steels. The characterisation of microstructure, in particular the methods for the analysis of the chemical composition of precipitates has progressed since the availability of X-ray energy dispersive analysis in the 1970s, and the role played by electron energy loss spectroscopy in providing quantitative analysi...

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Processes, microstructure and properties of vanadium microalloyed steels

The upper bainite structures were investigated in Fe–9Ni–(0.15–0.5)C (mass%) alloys transformed at temperatures between 723 and 623 K. A bainite packet similar to lath martensite is formed and is partitioned into blocks containing lath-shaped bainitic ferrite with the same parallel close-packed plane relationship of the K–S relationship. Its feature is categorized into three types: (A) a packet contains laths of two K–S variants with a small misorientation (sub-blocks), (B) a packet is divided by blocks largely misoriented and each block contains sub-blocks and (C) a packet is divided by blocks containing a single variant of laths. A packet of type (A) is formed at 723 K in each alloy whereas the packet type becomes (B) or (C) at lower temperatures. As a result, bainite blocks are refined with decreases in transformation temperature and carbon content. In contrast, blocks and packets of lath martensite are refined with increasing carbon content.

Crystallography of upper bainite in Fe-Ni-C alloys

The authors have investigated the behavior of casing pipe body and connections under simulated thermal recovery conditions. The study, performed in a new computer-controlled thermal-well simulator, examined the thermal stress behavior and leak resistance of pipe and connections at temperatures up to 354{degrees}C (670{degrees}F) under severe loading conditions similar to those encountered in thermal wells. We also studied the biaxial collapse resistance of the casing under the large axial tension that would exist after the cooling period in a steam-stimulation process. Results indicate that in a steam-injection process in which the casing is maintained at its maximum temperature for a period of time, stress relaxation can occur in a constrained production casing, resulting in the development of excessive tensile stress during the cooling period. Premium connections with metal-to-metal seals maintained gas leak resistance at temperatures up to 354{degrees}C (670{degrees}F), whereas the connections without metal seals did not. The biaxial collapse resistance of casing under large axial tension depended on the stress/strain characteristics of the material.

An experimental study of casing performance under thermal cycling conditions

The Fracture of Tempered Martensite

A threaded joint for oil-well pipe comprises a box having an internal thread, a pin having an external thread, a metal-to-metal sealing contact provided at the unthreaded tips of the box and pin, and a film of grease applied on the surface of the internal and external threads. The cross-sectional area of a void containing the screw axis left between the meshed internal and external threads is at least 0.6 mm 2 per pitch.

Threaded joint for oil-well pipe

Solubility of V 4 C 3 in α -Iron

PURPOSE:In soft steel or low alloy steel, the content of S is reduced to less than 0.0018% to thereby enhance the resistance against hydrogen induced blister and cracking in a gas or liquid atomosphere containing H2S, etc. CONSTITUTION:A new soft steel contains C: 0.002 to 0.20%, Si: 0.02 to 1.0%, Mn: 0.2 to 2.5%, sol Al<0.10%, and as inpurities P<0.05%, S<0.0018%, N< 0.01%, O<0.0025%. A new low alloy steel includes the above components and additionally a small amount of one or more of Nb, V, Mo, Cr, B, Ni, Cu, W, Bi, rare earth metals, Sb, Se, Te, Ti, and Zr. The extremely small content of S reduces the amount of nonmetal inclusives mainly consisting of MnS. The sulfide in these steel is controlled so that the area of greater than 90% of the total sulfide I in steel in the figure is occupied by ones in dimensions of less than 3muWX15mu1, and that greater than 90% of sulfide of point-line B series group is occupied by ones less than 50 in length.

Masao Ogasawara

Papers

An experimental study of casing performance under thermal cycling conditions

The Fracture of Tempered Martensite

Threaded joint for oil-well pipe

Solubility of V 4 C 3 in α -Iron

Steel highly resistant against hydrogen induced blister and cracking