A kind of titanium alloy oil pipe short joint surface treatment method

Abstract

The invention discloses a method for treating the surface of a titanium alloy oil pipe short joint. The steps are as follows: 1) cutting a required length short joint from a titanium alloy oil pipe blank, and processing the pipe end into a threaded joint; The short joints of alloy oil pipes are subjected to overall sandblasting treatment, cleaning and degreasing treatment in sequence; 3) HF+HNO is used 3 The solution pickled the short joint of titanium alloy oil pipe, and cleaned the short joint of titanium alloy oil pipe after pickling; 4) After pickling, put the short joint of titanium alloy oil pipe into the micro-arc oxidation mixed electrolyte, and used DC pulse current to Micro-arc oxidation treatment of the inner and outer surfaces of the titanium alloy oil pipe short joint; 5) Finally, ultrasonic cleaning, drying, coding, packaging and storage of the titanium alloy oil pipe short joint. The method can be used to form a dense micro-arc oxidation ceramic coating on the surface of the short joint of titanium alloy tubing. Service safety.

Description

Technical field: [0001] The present invention relates to the field of surface modification of petroleum machinery and metal materials, and more particularly to a short surface treatment method for titanium alloy tubes. Background technique: [0002] With the increasing demand for oil and gas resources such as deep and super-deep layers, especially H 2 S, CO 2 , CL - The oil and gas resources such as high corrosion medium have put forward higher requirements for oil pipe performance. For example, oil and gas fields in Southwest China contain high H 2 S, CO 2 , CL - Equal corrosion media, oilfield operation pipe column, downhole tools, etc., and other high alloy pipes such as nickel-based alloys, super stainless steel. The titanium alloy is characterized by the characteristics of high quality ratio, excellent corrosion resistance, and is one of the selection of pipes such as replacement nickel-based alloys. However, the tubular threaded joints are highly frictional coefficient, and...

AI Technical Summary

Problems solved by technology

However, due to the high surface friction coefficient of the titanium alloy pipe threaded joint, it is easy to cause scratches, friction damage and other sticking phenomena, and when the threaded joint is connected with other materials (such as low alloy steel, nickel-based alloy, stainless steel) downhole tools, Especially for short joints made of titanium alloy, galvanic corrosion and crevice corrosion occur at the joint connection, which accelerates the failure of the pipe

[0003] The application number published on May 29, 2014 is 201410233315.0, which involves a titanium alloy oil pipe thread anti-sticking surface treatment method, which performs micro-arc oxidation on the titanium alloy surface, and uses molybdenum disulfide powder and high-temperature adhesive Coating treatment, this method solves the problem of titanium alloy sticking and fastening, but this patent uses double-layer coating, which does not consider the problem of galvanic corrosion and crevice corrosion. Generally, the friction coefficient of the micro-arc oxidation layer will be relatively large, and this patent also The problem of friction coefficient of micro-arc oxidation layer is not involved

The patent No. ZL201610565692.3 applied for on July 18, 2016 involves a surface treatment method for titanium alloy oil pipe threads, which uses chemical nickel-phosphorus plating to modify the surface to improve the wear resistance and resistance of the titanium alloy thread surface. Fastening performance, but although the patent reduces the surface friction coefficient, it does not consider the problems related to galvanic corrosion and crevice corrosion