Tubular threaded member with dry protection coating

Abstract

A tubular threaded element including a dry protective coating. The coating includes a solid matrix adhering to the substrate in which there are dispersed particles of at least one solid lubricant belonging to one and the same class. The solid matrix is lubricating and has a rheological behaviour of plastic or viscoplastic type. The coating protects the threadings of the threaded elements, used for example in hydrocarbon wells, from corrosion and galling.

1 - 43 . (canceled) 
     
     
         44 . A threaded element for a tubular threaded joint which is resistant to galling, comprising:
 a threading covered with a thin coating in the solid state, not sticky to the touch and adhering to the substrate, which comprises a solid matrix and, in the matrix, a dispersion of particles of at least one solid lubricant, wherein the solid matrix is lubricating and presents a rheological behaviour of plastic or viscoplastic type.   
     
     
         45 . A threaded element according to  claim 44 , wherein the matrix has a melting point of between 80 and 320° C. 
     
     
         46 . A threaded element according to  claim 44 , wherein the matrix comprises at least one thermoplastic polymer and debris re-agglomeration means for re-agglomerating debris formed in the vicinity of the surface of the threaded element by friction. 
     
     
         47 . A threaded element according to  claim 46 , wherein the thermoplastic polymer is polyethylene. 
     
     
         48 . A threaded element according to  claim 44 , wherein the matrix comprises at least one metallic soap. 
     
     
         49 . A threaded element according to  claim 48 , wherein the soap is zinc stearate. 
     
     
         50 . A threaded element according to  claim 44 , wherein the matrix comprises at least one wax of vegetable, animal, mineral, or synthetic origin 
     
     
         51 . A threaded element according to  claim 50 , wherein the wax is carnauba wax. 
     
     
         52 . A threaded element according to  claim 44 , wherein the matrix comprises at least one corrosion inhibitor. 
     
     
         53 . A threaded element according to  claim 52 , wherein the corrosion inhibitor is a derivative of calcium sulphonate. 
     
     
         54 . A threaded element according to  claim 48 , wherein the soap is selected to improve the time for appearance of corrosion in the saline mist test in accordance with standard ISO 9227. 
     
     
         55 . A threaded element according to  claim 44 , wherein the matrix comprises at least one liquid polymer of a kinematic viscosity at 100° C. which is at least equal to 850 mm 2 /s. 
     
     
         56 . A threaded element according to  claim 55 , wherein the liquid polymer is water-insoluble. 
     
     
         57 . A threaded element according to  claim 55 , wherein the liquid polymer is selected from an alkyl polymethacrylate, a polybutene, a polyisobutene, and a polydialkylsiloxane. 
     
     
         58 . A threaded element according to  claim 44 , wherein the matrix comprises at least one surface-active agent. 
     
     
         59 . A threaded element according to  claim 44 , wherein the matrix comprises at least one coloring agent. 
     
     
         60 . A threaded element according to  claim 44 , wherein the matrix comprises at least one anti-oxidant. 
     
     
         61 . A threaded element according to  claim 44 , wherein the dispersion of particles of at least one solid lubricant comprises particles of lubricant of a single one of classes 1, 2, 3 or 4. 
     
     
         62 . A threaded element according to  claim 61 , wherein the particles of solid lubricants are selected from particles of lubricant of class 1, excluding graphite particles. 
     
     
         63 . A threaded element according to  claim 61 , wherein the particles of solid lubricants comprise particles of at least one solid lubricant of class 1 selected from boron nitride and zinc oxide. 
     
     
         64 . A threaded element according to  claim 61 , wherein the particles of solid lubricants are selected from particles of lubricant of class 2 excluding particles of molybdenum disulphide. 
     
     
         65 . A threaded element according to  claim 61 , wherein the particles of solid lubricants comprise particles of at least one solid lubricant e f class 2 selected from graphite fluoride, tin sulphides and bismuth sulphides. 
     
     
         66 . A threaded element according to  claim 61 , wherein the particles of solid lubricants comprise particles of at least one solid lubricant of class 4 selected from polytetrafluoroethylene and polyamide-11. 
     
     
         67 . A threaded element according to  claim 61 , wherein the composition by weight of the matrix is as follows: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   polyethylene homopolymer 
                   8 to 90% 
                 
                     
                   carnauba wax 
                   5 to 30% 
                 
                     
                   zinc stearate 
                   5 to 30% 
                 
                     
                   derivative of calcium sulphonate 
                   0 to 50% 
                 
                     
                   alkyl polymethacrylate 
                   0 to 15% 
                 
                     
                   colouring agent 
                   0 to 1% 
                 
                     
                   anti-oxidant 
                   0 to 1% 
                 
                     
                   silicone (surface-active element) 
                   0 to 2% 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         68 . A threaded element according to  claim 67 , wherein the silicone is polydimethylsiloxane or that marketed by DOW CORNING under the trade name DC56. 
     
     
         69 . A threaded element according to  claim 61 , wherein the composition by weight of the coating is as follows:
 matrix 70 to 95%   solid lubricants 5 to 30%   
     
     
         70 . A threaded element according to  claim 61 , wherein the thickness of the coating is between 10 μm and 50 μm. 
     
     
         71 . A threaded element according to  claim 61 , wherein the coating is also applied to a sealing surface capable of being in sealing tight contact with a corresponding sealing surface of a second threaded element after assembly by makeup of the two threaded elements. 
     
     
         72 . A threaded element according to  claim 44 , wherein the coating comprises molecules of at least one fullerene of spherical geometry. 
     
     
         73 . A tubular threaded joint comprising:
 a male threaded element and a female threaded element, wherein one at least of the threaded elements is in accordance with  claim 44 .   
     
     
         74 . A process for finishing a tubular threaded element, wherein an anti-galling coating in a form of a thin layer is applied at least to the surface of the threading to produce a solid coating, wherein the surface to be coated is subjected to a surface treatment for improving adhesion of the coating and constituents of that coating are as defined in  claim 44 . 
     
     
         75 . A process according to  claim 74 , wherein the constituents of the coating are raised to a temperature higher than the melting temperature of the matrix and then the coating is applied by spraying of the constituents comprising the matrix in a molten state. 
     
     
         76 . A process according to  claim 75 , wherein the coating is applied by projection through a flame of a powder formed by the constituents of the coating. 
     
     
         77 . A process according to  claim 76 , wherein the coating is applied by spraying an aqueous emulsion in which the constituents of the coating are dispersed. 
     
     
         78 . A process according to  claim 74 , wherein the threaded element is raised to a temperature higher than or equal to 80° C. 
     
     
         79 . A process according to  claim 74 , wherein the threaded element is at ambient temperature. 
     
     
         80 . A process according to  claim 74 , wherein the surface treatment is selected from mechanical treatments, chemical treatments, and non-reactive deposits. 
     
     
         81 . A process according to  claim 74 , wherein the surface to be coated is a metallic surface and the surface treatment is a treatment for chemical conversion of the surface. 
     
     
         82 . A process according to  claim 81 , wherein the chemical conversion treatment is a phosphatation process. 
     
     
         83 . A process according to  claim 74 , wherein the surface treatment is followed by a treatment for impregnation of roughness or porosities of the surface to be coated with nanomaterials with an anti-corrosion action. 
     
     
         84 . A process according to  claim 83 , wherein the nanomaterials are particles of zinc oxide. 
     
     
         85 . A process according to  claim 83 , wherein the nanomaterials are of a median particle size of the order of 200 nm. 
     
     
         86 . A process according to  claim 83 , wherein the nanomaterials are applied in a form of a dispersion.