Method for manufacturing high steel grade sulfur resistant drill pipe by laser cladding

Abstract

The invention relates to a method for manufacturing a high steel grade sulfur-resistant drill pipe by laser cladding. In the method, in the condition of inert gas insulating air, nickel-base alloy anti-corrosion material is clad on the inner and outer pipe walls of an S135 steel grade drill pipe with conventional properties by laser, a nickel-base alloy anti-corrosion layer is clad on the non-thread area of a joint, threads are processed on the thread conical surface of the joint after a nickel-base alloy anti-corrosion layer is clad on the thread conical surface of the joint, and the end part of a pipe body is oppositely connected with the joint through friction welding; the output power of the laser is 3.5-4.5kW; laser beam spot size is not more than Phi 3mm; defocusing amount is 25-35mm; laser beam scanning line speed is 6.5-7.5mm / s; the inclined angle between the laser beam and the long axis direction of the pipe body is 40-50 degree; and the delivery rate of cladding wire material is 15-20g / s. The drilling pipe reaches the property of the S135 steel grade drilling pipe by the APE Spec standard. The cladding layer can effectively prevent a base body from contacting natural gas to improve the H2S-resistant stress corrosion cracking performance.

Description

technical field [0001] The invention relates to a method for preparing a high steel grade sulfur-resistant drill pipe by laser cladding for drilling a drill string component in a highly acidic hydrogen sulfide-containing gas field with laser surface treatment. Background technique [0002] Drill pipe is an essential tool in oil drilling engineering. The technical issue that needs to be considered for conventional drill pipes is to meet the general drilling conditions, mainly mechanical properties. Western gas fields such as the Sichuan-Chongqing gas field are the main areas in the development of domestic oil and gas resources, but the gas fields in this area have a rather high H 2 S content, in addition to the uniform corrosion that can be detected and monitored, also has some failure forms such as stress corrosion cracking that originate from internal damage of the material, which is at great risk. Therefore, sulfur-resistant drill pipe must be used to ensure the safety o...

AI Technical Summary

Problems solved by technology

The current sulfur-resistant drill pipe steel grade is up to 105ksi, that is, the yield strength can reach up to 724MPa. If it exceeds this critical value, the drill pipe material is very sensitive to strength and is prone to brittle fracture.

The well depth of oil and gas fields in western China is usually more than 5,000 meters, and the strength of 105ksi steel grade drill pipe cannot meet the actual drilling needs.

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