Key threaded articles and systems that include key threads having a female lock and male key on a two-dimensional plane and in which the female lock envelops the male key when fully engaged and has a shape that creates lateral resistance to separation from the male key when the female lock fully engages the male key.

A pipe fitting having a first body and a second body that together at least partially define a fluid flow passage. The first body defines a first portion of the fluid flow passage that extends from a first end of the fluid flow passage to a first internal opening. The second body defines a second portion of the fluid flow passage that extends from a second internal opening to a second end of the fluid flow passage. The first body has a first interface surface that surrounds the first internal opening, the first interface surface having a plurality of anti-rotation grooves. The second body has a second interface surface that surrounds the second internal opening and engages with the first interface surface. The first internal opening is in fluid communication with the second internal opening. The second interface surface has a plurality of anti-rotation fingers that are each received by and engage with a corresponding one of the anti-rotation grooves. Rotation of the second body relative to the first body is resisted by the engagement of the anti-rotation fingers with the anti-rotation grooves.

A pipe fitting having a first body and a second body that together at least partially define a fluid flow passage. The first body defines a first portion of the fluid flow passage that extends from a first end of the fluid flow passage to a first internal opening. The second body defines a second portion of the fluid flow passage that extends from a second internal opening to a second end of the fluid flow passage. The first body has a first interface surface that surrounds the first internal opening, the first interface surface having a plurality of anti-rotation grooves. The second body has a second interface surface that surrounds the second internal opening and engages with the first interface surface. The first internal opening is in fluid communication with the second internal opening. The second interface surface has a plurality of anti-rotation fingers that are each received by and engage with a corresponding one of the anti-rotation grooves. Rotation of the second body relative to the first body is resisted by the engagement of the anti-rotation fingers with the anti-rotation grooves.

A sealing system connecting first and second tubular members includes a first curvilinear sealing surface on the first tubular member and a second curvilinear sealing surface on the second tubular member. Both the first and second curvilinear sealing surfaces are disposed between two sets of threading on the respective first and second tubular members. When the first and second tubular members are in a connected configuration, the first and second curvilinear sealing surfaces contact and interfere to form an annular curvilinear center seal. A relief pocket may be disposed adjacent to the first and/or second curvilinear sealing surfaces to contain excess lubricant between the first and second tubular members.

A sealing system connecting first and second tubular members includes a first curvilinear sealing surface on the first tubular member and a second curvilinear sealing surface on the second tubular member. Both the first and second curvilinear sealing surfaces are disposed between two sets of threading on the respective first and second tubular members. When the first and second tubular members are in a connected configuration, the first and second curvilinear sealing surfaces contact and interfere to form an annular curvilinear center seal. A relief pocket may be disposed adjacent to the first and/or second curvilinear sealing surfaces to contain excess lubricant between the first and second tubular members.

A threaded joint wherein a relationship between shoulder angle parameters and thread taper angle parameters for a coupling and a pair of pins inserted from both ends of the coupling is defined by the following expression (1), and a tightening torque with which the threaded joint is tightened is 60% or more and 85% or less of a yield torque determined by the following expression (2):

[00001]$\begin{array}{cc}-1.5°\le \Delta \theta -\Delta \omega \le 2.°,& \left(1\right)\end{array}$$\begin{array}{cc}T=\left(T_S+T_D\right)\frac{1}{12}& \left(2\right)\end{array}$$T_S=f_t{P}_c\frac{E_7}{2}\left(2\pi E_7\right)L_4\frac{1}{2}$$P_c=E\frac{{\rho }_m}{2}\frac{\left({\left(\frac{W}{2}\right)}^2-{\left(\frac{E_7}{2}\right)}^2\right)({\left(\frac{E_7}{2}\right)}^2}{}$

A threaded joint wherein a relationship between shoulder angle parameters and thread taper angle parameters for a coupling and a pair of pins inserted from both ends of the coupling is defined by the following expression (1), and a tightening torque with which the threaded joint is tightened is 60% or more and 85% or less of a yield torque determined by the following expression (2):

[00001]$\begin{array}{cc}-1.5°\le \Delta \theta -\Delta \omega \le 2.°,& \left(1\right)\end{array}$$\begin{array}{cc}T=\left(T_S+T_D\right)\frac{1}{12}& \left(2\right)\end{array}$$T_S=f_t{P}_c\frac{E_7}{2}\left(2\pi E_7\right)L_4\frac{1}{2}$$P_c=E\frac{{\rho }_m}{2}\frac{\left({\left(\frac{W}{2}\right)}^2-{\left(\frac{E_7}{2}\right)}^2\right)({\left(\frac{E_7}{2}\right)}^2}{}$

Threaded tubular connection for the casing of hydrocarbon wells obtained by makeup of a male tool joint with a female tool joint, the connection includes in order from a free edge of the male tool joint: an inner metal-metal seal, a first threaded portion, an intermediate abutment, an intermediate metal-metal seal and a second threaded portion, the free edge being at a non-zero axial distance from the female tool joint, the threaded portions each comprising a helix equipped with a load flank, a thread crest, a stabbing flank, a thread root, such that a pitch of the load flank and a pitch of the stabbing flank of the first threaded portion, and respectively a pitch of the load flank and a pitch of the stabbing flank of the second threaded portion fulfil the following condition: SFLb1=LFLb1=SFLb2=LFLb2=SFLp1=SLFLp2=LFLp2.

Threaded tubular connection for the casing of hydrocarbon wells obtained by makeup of a male tool joint with a female tool joint, the connection includes in order from a free edge of the male tool joint: an inner metal-metal seal, a first threaded portion, an intermediate abutment, an intermediate metal-metal seal and a second threaded portion, the free edge being at a non-zero axial distance from the female tool joint, the threaded portions each comprising a helix equipped with a load flank, a thread crest, a stabbing flank, a thread root, such that a pitch of the load flank and a pitch of the stabbing flank of the first threaded portion, and respectively a pitch of the load flank and a pitch of the stabbing flank of the second threaded portion fulfil the following condition: SFLb1=LFLb1=SFLb2=LFLb2=SFLp1=SLFLp2=LFLp2.

Threaded tubular connection for the casing of hydrocarbon wells obtained by makeup of a male tool joint with a female tool joint, the connection comprising a threaded portion (16a, 18a), such that the male and respectively female threaded portions each comprise a helix provided with a load flank, a thread crest, a stabbing flank, a thread root, such that a pitch of the load flank (LFLp, LFLb) and a pitch of the stabbing flank (SFLp, SFLb) fulfils the following condition: [Math 22] SFL.sub.b=LFL.sub.b=SFL.sub.p=LFL.sub.p=k, A tooth width (Wtp) of the male helix and a tooth width of the female helix (Wtb) are such that [Math 23] or [Math 24] and [Math 25] Wtp+Wtb<k