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Strengthened composite layer on rotor surface of screw drilling tool and machining process thereof

A technology for rotor surface and screw drilling tools, which is applied to layered products, earth-moving drilling, drilling equipment, etc. Service life, low porosity, long service life effect

Inactive Publication Date: 2015-07-22
KINGDREAM PLC CO +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the surface of the rotor produced at home and abroad mostly adopts the traditional electroplating hard chromium strengthening process, and a layer of hard chromium is plated on the surface of the rotor. The hard chromium layer has the advantages of high hardness, wear resistance, corrosion resistance and low cost, but it has the advantages of Corrosive brine-saturated mud medium and hydrogen sulfide-containing well sections are used for a long time, and the coating is prone to large-area pitting corrosion and even dechromation. In severe cases, the entire motor assembly will be scrapped, directly affecting the service life of the screw drilling tool
The reason is that the hardness of ordinary hard chrome layer is high, and there are many microcracks inside the hard chrome layer, which will inevitably produce penetrating cracks, resulting in the penetration of corrosive media (such as chloride ions, sulfur ions) from the surface to the interface through microcracks. Corrosion of the rotor base (usually steel), resulting in rust spots, pitting and even peeling on the surface of the hard chromium layer
[0004] U.S. Patent US 5395221 discloses a screw rotor coated with reinforced carbide or boride coating on the surface. The rotor treated with this technology can withstand the drilling environment of corrosive media such as salt water and has better wear resistance, but The disadvantage is the high cost

Method used

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  • Strengthened composite layer on rotor surface of screw drilling tool and machining process thereof
  • Strengthened composite layer on rotor surface of screw drilling tool and machining process thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Embodiment 1 Electroplating strengthening composite layer (milky white chrome layer-hard chrome layer)

[0035] The chemical composition of the electroplating bath solution for electroplating the milky white chromium layer and the hard chromium layer is: chromic anhydride 230-280g / L, sulfuric acid 2.3-2.8g / L, trivalent chromium 3-8g / L. First, electroplate the milky white chrome layer on the surface of the screw drill rotor, and the process parameters of the electroplating milky white chrome layer are: temperature 70-75°C, cathode current density 15-25A / dm 2 , coating thickness 0.02-0.06mm. Then electroplate a hard chromium layer on the surface of the screw drill rotor, and the process parameters of electroplating hard chromium layer: temperature 52-55℃, cathode current density 35-40A / dm 2 , coating thickness 0.10-0.15mm. Metallographic examination results show that a dense opalescent chromium layer is formed adjacent to the substrate. The wear amount of the wet sand ...

Embodiment 2

[0037] Embodiment 2 Electroplating strengthening composite layer (milky white chrome layer-hard chrome layer)

[0038] The chemical composition of the electroplating bath solution for electroplating milky white chrome layer and hard chrome layer is: chromic anhydride 230-280g / L, sulfuric acid 2.3-2.8g / L, trivalent chromium 3-8g / L, hard chrome additive 20mL / L. First, electroplate the milky white chrome layer on the surface of the screw drilling tool rotor, and the process parameters of the milky white chrome layer are: temperature 80-85°C, cathode current density 15-25A / dm 2, coating thickness 0.02-0.06mm. Then electroplate a hard chromium layer on the surface of the screw drill rotor, and the process parameters of electroplating hard chromium layer: temperature 60-65℃, cathode current density 35-40A / dm 2 , coating thickness 0.10-0.15mm. The results of metallographic examination show that a dense opalescent chromium coating is formed adjacent to the substrate. Wear test and ...

Embodiment 3

[0039] Embodiment 3 Electroplating strengthening composite layer (double nickel-hard chromium layer)

[0040] First electroplate the semi-bright nickel layer, the chemical composition of the electroplating bath is: nickel sulfate 280-320g / L, nickel chloride 38-47g / L, boric acid 45-50g / L, wetting agent (sodium lauryl sulfate) 1-3mL / L, appropriate amount of brightener (butynediol), process parameters: temperature 52±2°C, cathode current density 2.5-4.5A / dm 2 , pH3.6-4.5, coating thickness 0.02-0.05mm;

[0041] Then electroplate the bright nickel layer, the chemical composition of the electroplating bath solution is: nickel sulfate 200-240g / L, nickel chloride 75-150g / L, wetting agent (2-ethylhexyl sodium sulfate) 1-3mL / L, bright Agent (propoxybutynediol) 5-40mL / L, process parameters: temperature 52±2℃, cathode current density 3-5A / dm 2 , pH3.5-4.4, coating thickness 0.005-0.03mm;

[0042] Finally, the hard chromium layer is electroplated. The chemical composition of the electr...

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Abstract

The invention relates to a strengthened composite layer on a rotor surface of a screw drilling tool and a machining process of the strengthened composite layer. The strengthened composite layer is divided into a base layer and a hard chromium layer from the rotor surface to the outside in sequence, wherein the base layer is a creamy white chromium layer or a double-nickel layer composed of a semi-bright nickel layer and a bright nickel layer. The machining process of the strengthened composite layer comprises the following steps: electroplating a base layer on the rotor surface, wherein the base layer is a creamy white chromium layer or a double-nickel layer composed of the semi-bright nickel layer and the bright nickel layer; then, electroplating a hard chromium layer; forming a composite plated layer by the base layer and the hard chromium layer to enhance the strength of the rotor surface. The method is used for effectively solving the problems that the rotor of the screw drilling tool in the prior art is poor in corrosion resistance, is not suitable for the drilling environments with brine-saturated mud medium or is high in cost, and can obtain the rotor of the screw drilling tool with a plurality of excellent performances. With the adoption of the process provided by the invention, the prepared rotor of the screw drilling tool is good in corrosion resistance and wear resistance, high in hardness, and long in service life (in saline environment, the service life of the composite plated layer rotor screw prepared by the process of the invention is up to 250-300 hours).

Description

technical field [0001] The invention belongs to the technical field of materials for petroleum geological drilling screw tools, and in particular relates to a process for strengthening the surface of a screw drilling tool rotor. Background technique [0002] The screw drilling tool is a downhole tool powered by mud, which consists of five parts: drive shaft assembly, cardan shaft assembly, motor assembly, anti-drop assembly and bypass valve assembly. The performance of the screw drilling tool mainly depends on the motor assembly. The motor assembly is composed of a stator and a rotor. The stator is formed by injection of rubber bushings on the inner wall of the steel pipe. The inner hole of the rubber is a spiral with certain geometric parameters. The rotor is a screw with a hard layer. The rotor and the stator are meshed with each other, and the lead difference between the two is used to form a spiral sealed cavity to complete energy conversion. [0003] The motor assembl...

Claims

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Application Information

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IPC IPC(8): C25D5/14C25D3/04C25D3/12E21B4/02B32B15/01
Inventor 毛红兵
Owner KINGDREAM PLC CO
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