Patent RU-2643397-C2 (RU)
Inventor: TIMOFEEV VLADIMIR IVANOVICH
IPC: E21B17/10
Filed: 2016-07-26
Granted: 2018-02-01
Abstract: FIELD: metallurgy. 
     SUBSTANCE: method of attachment of inserts from tungsten carbide on substrate of casing centralizers includes the following stages during which the substrate of strengthened surfaces of casing centralizers is burnt by a burner, a stabilizing composition is applied on the base of nickel alloy on the substrate of casing centralizers for protection against oxidation, inserts made of tungsten carbide are installed in holes of perforated flexible mat according to the same layout as the order of the inserts placement on the substrate, the perforated flexible mat with inserts made of tungsten carbide is installed on the substrate in such a manner, so that the welds for contacting with the substrate are directed towards the substrate, tungsten carbide inserts located on the perforated flexible mat are fixed to substrate, inserts of tungsten carbide are heated on substrate of strengthened surfaces, the stabilizing nickel-based composition is sprayed on the surface of inserts of tungsten carbide, which are fixed on the substrate of the strengthened surfaces for protection against oxidation, the stabilizing nickel-based alloy composition is heated on the surface of the inserts of tungsten carbide, which are fixed on the substrate of strengthened surfaces for protection against oxidation, the stabilizing nickel-based alloy composition is sprayed and inserts of tungsten carbide are soldered to the substrate of strengthened surfaces so, so that the material of the stabilizing nickel-based alloy composition flows between the inserts of tungsten carbide and the substrate of the strengthened surfaces, the stabilizing nickel-based alloy composition is melted. At that, each tungsten carbide insert has welding projections on the contact end for contacting with the substrate of strengthened surfaces for placement of the end of the tungsten carbide insert at a certain distance from the substrate. And welding projections on the ends of tungsten carbide inserts provide clearance between said tungsten carbide inserts end and the substrate of strengthened surfaces after the welding. The tungsten carbide inserts are used, each of which is in the form of rectangular block with three welding projections on the contact end, two welding projections are placed along the edge of the long side of the tungsten carbide insert, the third welding projection is positioned at the opposite edge of the long side of said tungsten carbide insert. At that, the height h of the welding projections on the contact end of each tungsten carbide insert is selected from the ratio: h=(0.08÷0.12) h, where H is height of tungsten carbide insert. Each tungsten carbide insert is installed in the hole on the perforated flexible mat with its long side with two welding projections along the blade of the casing centralizer. The width T of the gaps between the tungsten carbide inserts is selected from the ratio: T=(8.55÷11.55) h, where h is the height of welding projections on the contact end of tungsten carbide inserts. The tungsten carbide inserts are attached to the substrate by means of point condenser welding carried out by the energy of a short current pulse during discharge of the condenser bank. 
     EFFECT: extended service life of the casing centralizers by increasing the strength and wear resistance of carbide inserts on the wear surfaces of the casing centralizers. 
     4 cl, 9 dwg