Connecting element for a tubular component overlaid with a metallic composite deposit and method of obtaining such element

Abstract

A connecting element for a tubular component, the connecting element being overlaid with a coating including a principal layer constituted by a nickel-phosphorus alloy, a tubular component including one or more such connecting elements, and a method for producing such a connecting element.

Claims

1. A connecting element for a tubular component, overlaid with a coating comprising: a principal layer consisting of a nickel-phosphorus alloy, and an additional layer constituted by the nickel-phosphorus alloy comprising particles of one or more solid lubricant compounds, the additional layer being disposed on the principal layer, wherein phosphorous represents 10.5% to 11.5% by weight of a total weight of the nickel-phosphorous alloy.

2. A connecting element according to claim 1, wherein a thickness of the principal layer constituted by the nickel-phosphorus alloy is in a range of 5 to 10 m.

3. A connecting element according to claim 1, wherein a thickness of the principal layer constituted by the nickel-phosphorus alloy is in a range of 15 to 35 m.

4. A connecting element according to claim 1, wherein the particles of one or more solid lubricant compounds are one or more particles selected from a list consisting of polytetrafluoroethylene, talc, mica, boron nitride, silicon carbide, tungsten carbide, tungsten sulphide, molybdenum sulphide.

5. A connecting element according to claim 1, wherein the particles of one or more solid lubricant compounds represent 20% to 35% by volume with respect to a total volume of the nickel-phosphorus alloy comprising the particles of one or more solid lubricant compounds.

6. A connecting element according to claim 1, wherein a thickness of the additional layer constituted by a nickel-phosphorus alloy comprising the particles of one or more solid lubricant compounds is in a range of 3 to 13 m.

7. A connecting element according to claim 1, wherein the coating comprises a lubricant layer disposed on the principal layer or on the additional layer when the coating comprises the additional layer.

8. A connecting element according to claim 7, wherein the lubricant layer is selected from a grease, a semi-solid lubricant layer or a solid, dry lubricant layer comprising one or more solid lubricant particles in a resin.

9. A connecting element according to claim 1, which is a threading.

10. A connecting element according to claim 1, which is a sealing surface.

11. A connecting element according to claim 1, which is an abutment shoulder.

12. A tubular component comprising one or more connecting elements as defined in claim 1.

13. A tubular component according to claim 12, wherein the one or more connecting elements is a threading.

14. A tubular component according to claim 12, wherein the one or more connecting elements is a sealing surface.

15. A tubular component according to claim 12, wherein the one or more connecting elements is an abutment shoulder.

16. A method for obtaining a connecting element as defined in claim 1, comprising depositing the principal layer and the optional additional layer by autocatalytic deposition.

17. A method according to claim 16, further comprising posterior treatment at a temperature in a range of 250 C. to 300 C.

18. A method according to claim 16, further comprising posterior treatment at a temperature in a range of 300 C. to 600 C.

19. An assembly of a first tubular component and a second tubular component, the first tubular component including a threaded male portion, the second tubular component including a correspondingly threaded female portion configured to accommodate the male portion, one of the threaded male portion and the threaded female portion overlaid with a coating comprising: a principal layer consisting of a nickel-phosphorus alloy, and an additional layer constituted by the nickel-phosphorus alloy comprising particles of one or more solid lubricant compounds, the additional layer being disposed on the principal layer, wherein phosphorous represents 10.5% to 11.5% by weight of a total weight of the nickel-phosphorous alloy.

Description

(1) FIG. 1 is a diagrammatic view of a connection resulting from connecting two tubular components by makeup.

(2) FIG. 2 is an enlarged view of the zone in box A of FIG. 1.

(3) FIG. 3 is a detailed view of the cooperation between the threads of two connected tubular components.

(4) FIG. 4 is a detailed view of a connecting element (threading) of the invention overlaid with a coating.

(5) The threaded connection shown in FIG. 1 comprises a first tubular component with an axis of revolution 9 provided with a male end 1 and a second tubular component with an axis of revolution 9 provided with a female end 2. The two ends 1 and 2 each end in a terminal surface orientated radially with respect to the axis 9 of the threaded connection and are respectively provided with threaded portions 3 and 4 which cooperate together for mutual connection by makeup of the two components. The threaded portions 3 and 4 may be of the trapezoidal or other thread type. In the example shown, the threaded portions have threads with a vanishing profile at the respective ends of the threaded portions. These vanishing profiles extend over a portion of the axial extent of the threaded portion. In particular, a portion of the threaded portion with a vanishing profile 10 does not cooperate with a complementary threading.

(6) In addition, as can be seen in FIG. 2, metal/metal sealing surfaces (bearing surfaces) 5, 6 intended to come into an interference sealing contact one against the other after connection of the two threaded components by makeup are respectively provided on the male and female ends close to the threaded portions 3, 4. Finally, the male end 1 ends in a terminal surface 7 which abuts against a corresponding surface 8 provided on the female end 2 when the two ends are made up one into the other. The surfaces 7 and 8 are termed abutment shoulders.

(7) FIG. 3 shows a detail of a thread of a threaded portion. Each thread thus comprises a load flank 11 forming an angle 12 in the range 5 to +5 with respect to the normal N to the connection axis 10. The load flank is connected via a crest 13 to a stabbing flank 14. In particular, the connection shown is such that in the final position of the connection, the load flanks of the male threaded portion 3 are in contact with the corresponding load flanks of the female threaded portion 4.

(8) FIG. 4 shows the male end 1 of a tubular component in which the threaded portion 3 and the sealing surface 5 (bearing surface) are overlaid with a coating 15 as defined in the invention.

EXAMPLE

(9) A metallic coating of a principal layer of a nickel-phosphorus alloy comprising 11% by weight of phosphorus, and an additional layer of a nickel-phosphorus alloy comprising polytetrafluoroethylene (PTFE) particles in an amount of 25% by volume with respect to the volume of the alloy, was produced on a L80 grade carbon steel threading.

(10) The principal layer was deposited using the autocatalytic method proposed by the company MACDERMID with the trade name NiKlad ELV.

(11) The additional layer was deposited using the autocatalytic method proposed by the company MACDERMID with the trade name NiKlad ICE ULTRA.

(12) The principal nickel-phosphorus layer was 29 m thick. The additional nickel-phosphorus-PTFE layer was 7.4 m thick.

(13) The metallic composite deposit obtained had a hardness of at least 550 Hk under 10 g.

(14) The metallic composite deposit had very good corrosion resistance.

(15) Tests were carried out on the shore at a marine industrial exposure site (port of Dunkirk) classed as level 4 (high) on a scale of up to C5 (see Corrosivity Class in accordance with ISO standard 9223).

(16) After 12 months exposure in Dunkirk with a protector, no signs of rust were observed.

(17) After 12 months exposure in Dunkirk without a protector, a few rare spots of corrosion were observed (Re 1 on the European scale for degree of rusting, ISO 4628-3).

(18) After 24 months exposure in Dunkirk with a protector, no signs of rust were observed.

(19) The metallic composite deposit was not damaged during a scratch test type test where it was subjected to an increasing load from 10N to 300N provided by a tungsten carbide bead with a diameter of 5 mm. In contrast to other metallic deposits (CuSnZn alloy type), the deposit does not crack; no detachment or delamination of the coating was observed.

(20) The metallic composite deposit had excellent anti-galling performances.

(21) Laboratory tests (Vee block test with a constant 785N load, equivalent to a contact pressure of 500-600 MPa, characteristic of the contact pressures occurring during makeup of a connection at the threads) exhibited highly progressive wear during use of nickel-phosphorus supplemented with PTFE compared with a metallic deposit of a ternary CuSnZn alloy.

(22) Makeup curves very similar to those obtained with an API grease were obtained: highly regular slopes (not bumpy), with clearly identifiable changes in the slope.

(23) Corrosion tests according to ISO Standard 9227Corrosion tests in artificial atmospheres or salt spray testshave been carried out on a sample corresponding to the example described above (noted with sample reference D) and was compared to samples with various thicknesses of constituting layers. All the samples are L80 grade carbon steel threaded elements overlaid with a principal layer of a nickel-phosphorus alloy comprising 11% by weight of phosphorus, and an optional additional layer of a nickel-phosphorus alloy comprising polytetrafluoroethylene (PTFE) particles in an amount of 25% by volume with respect to the volume of the alloy.

(24) All those samples have been exposed to neutral spray test (NSS) for at least 1000 hours, Results are given according to ISO standard 9227, on a European scale with levels of rust ranging from Re0 to Re9; level Re0 corresponding to a 0% rusted surface; Re3 corresponding to a 1% rusted surface; Re5 corresponding to a 8% rusted surface; Re6 corresponding to a 40%-50% rusted surface.

(25) TABLE-US-00001 Rust level after Rust level after Sample 500 h exposure 1000 h exposure reference Coating (Re scale) (Re scale) A One principal layer 4.5 6 NiP from 25 m to 31 m B One principal layer 3 4.5 NiP from 15 m to 20 m and one additional layer of NiP-PTFE from 5 m to 10 m C One principal layer 2.6 4.5 NiP from 20 m to 25 m and one additional layer of NiP-PTFE from 5 m to 10 m D One principal layer 2.3 2.8 NiP from 25 m to 30 m and one additional layer of NiP-PTFE from 5 m to 10 m
The sample D with a coating comprising a principal layer of NickelPhosphorus alloy having a thickness in the range 25 m to 30 m and an additional layer of Nickel Phosphorus comprising particles of PTFE lubricant presents an excellent behaviour to corrosion.