Two-section type spray-welded coating smooth sucker rod and machining process thereof

Abstract

A two-section type spray-welded coating smooth sucker rod comprises a substrate and a nickel base alloy coating located on the surface of the substrate. The non-upsetting section is made from a high-strength and high-toughness steel substrate with the length being one to three meters. The upsetting section is made from a common steel substrate. The high-strength and high-toughness steel substrate of the non-upsetting section and the common steel substrate of the upsetting section are connected together in a friction welding mode. Weld joints and an influence zone need to be subjected to quenched-tempered heat treatment and surface nanocrystallization treatment before the nickel base alloy coating is prepared, and thus the excellent structure and mechanical performance is obtained. The novel alloy coating smooth sucker rod has good abrasion resistance and corrosion resistance, special strength and toughness improving design and treatment are conducted on a high-proportion fracture zone located below a smooth rod fastener by about 10 centimeters specifically, the excellent toughness, bending performance and fatigue resistance performance are achieved, the fracture problem of the alloy coating smooth sucker rod can be effectively solved, the service life of the smooth sucker rod is prolonged, and the normal operation of oil wells in oilfields is advantageously ensured.

Description

technical field [0001] The invention relates to petroleum equipment, more specifically to an oil pumping polished rod. Background technique [0002] The oil pumping rod is one of the most critical components in oil field artificial lift production, and its performance is directly related to the normal production of the oil well. Once the polished rod breaks, it will lead to oil well shutdown and workover operations, resulting in huge economic losses for maintenance and well shutdown. [0003] The reasons for the failure of polished rods mainly include three types: wear, corrosion and fracture. There have been many successful ways to solve wear and corrosion. For example, the nickel-based alloy coating spray-welded polished rod specified in the API 11B and SY / T 5029 standards has solved the wear and corrosion of the polished rod very well, and has become an oil field application. The widest range of polished rods. However, there is a big problem in the fracture of the poli...

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Problems solved by technology

[0004] The existing alloy-coated polished rods mainly improve the toughness of the coating through the following three ways, and it is expected to finally solve the fracture problem of the polished rod: one is to adjust the composition of the nickel-based alloy coating, but due to the requirements of the characteristics of the NiCrBSi self-fluxing alloy powder , there is not much room for composition improvement, and it is difficult to improve the toughness of the coating; the second is to use a new polished rod base material to improve the overall toughness and fatigue resistance of the coated polished rod by significantly improving the toughness and fatigue resistance of the polished rod base material , the effect of this method is remarkable, but since this kind of base material often needs to use special alloy steel with specific elements added, it makes its mechanical properties significantly improved, and at the same time, it is more difficult to process and heat treat, especially for oil pumping rods that need to be cooled For a series of processes such as drawing, heat treatment, upsetting, machining and thread extrusion, the cost is often unacceptable, and the control of the production process is also difficult, so it is difficult to be widely promoted; the third is through the NiCrBSi self-fluxing alloy powder Add Cu and other toughening components to improve the toughness and fatigue resistance of the coating itself. The existing products on the market also mainly use the technical method of adding Cu to the NiCrBSi self-fluxing alloy powder, but it improves the toughness. Limited, it is difficult to effectively solve the fracture of the polished rod

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