How To Improve The Anti-SSC Performance of OCTG Pipe

OCTG pipe include drill pipe, casing and tubing used on land and offshore, and are used in the oil and gas production field. What is SSC? SSC is sulfide stress cracking, which can cause materials to suddenly break without warning, leading to serious safety accidents and even catastrophic consequences. Especially in high-pressure and high-strength pipelines, SSC can cause major safety accidents, so special attention needs to be paid to the anti-SSC performance of OCTG pipes to ensure the safety of the pipeline.

The main methods for OCTG pipes to resist SSC include adjusting the chemical composition, heat treatment process and selecting appropriate materials. By optimizing these aspects, the sulfide stress corrosion resistance of OCTG pipes can be effectively improved.

Adjust chemical composition

Adjusting the chemical composition is the key to improving the SSC resistance of OCTG pipes. By controlling the content of carbon, manganese, phosphorus, sulfur, molybdenum, chromium, vanadium, titanium, copper and other elements, the SSC resistance of the material can be significantly improved. For example, the chemical composition of 90ksi steel grade OCTG pipe includes C 0.18%-0.22%, Mn 0.30%-0.45%, P≤0.015%, S≤0.003%, Mo 0.18%-0.2%, Cr 1.6%-1.8%, V 0.04%-0.06%, Ti 0.07%-0.09%, Cu 0.05%-0.17%, etc. The precise control of these components can help improve the SSC resistance of OCTG tubes.

Heat treatment process

The heat treatment process also has an important impact on the SSC resistance of OCTG pipes. Through quenching and tempering, the structure and properties of the material can be changed. Studies have shown that the increase in quenching temperature will lead to an increase in the size of the microstructure at all levels of tempered martensite, a reduction in the proportion of large-angle grain boundaries, and an increase in dislocation density, thereby affecting the SSC resistance. Therefore, by optimizing the quenching and tempering process, the structure and properties of the material can be effectively controlled and its SSC resistance can be improved.

Choose the right material

Selecting the appropriate material is also an important measure to resist SSC. In humid carbon dioxide environments, high chromium steels such as 9% Cr and 13% Cr martensitic stainless steel are widely used in the production of OCTG pipes. These materials have good CO2 corrosion resistance and can effectively resist sulfide stress corrosion. In addition, reasonable material selection can also select appropriate materials according to specific application environments and requirements, such as API standard oil well casing C-75, N-80 and P-110, etc. These materials perform well in different application scenarios. Anti-SSC performance.

Summary

Through the above methods, the sulfide stress corrosion resistance of OCTG pipes can be effectively improved to ensure their safe use in harsh environments.