Welding method for supercritical CO2 conveying pipeline tubular product

By performing V-shaped bevel processing and multi-layer welding treatment on the supercritical CO2 conveying pipeline pipes, the problem of insufficient low-temperature impact toughness of ring welding joints in the prior art is solved, and efficient and stable welding effect is achieved.

CN119703276AActive Publication Date: 2025-03-28CHINA NAT PETROLEUM CORP +3
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Patent Information

Application Number
CN202311268572.3
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2023-09-27
Publication Date
2025-03-28
Estimated Expiration
2043-09-27

AI Technical Summary

Technical Problem

In the prior art, the conveying supercritical CO2 pipeline pipes are less severe in the low temperature impact toughness of the ring welded joints, which leads to the problem of brittle breakage at low temperatures.

Method used

A welding method is adopted, including V-shaped bevel processing of the steel pipe, performing bevel grouping and preheating treatment, root welding and heat welding using a first gas protection welding machine, and then multi-layer multi-channel fill welding and cover welding using a second gas protection welding machine to form a complete welding layer.

Benefits of technology

Through this welding method, the low-temperature impact toughness of the ring welding joint is significantly improved, and the failure of the ring welding joint caused by large temperature drop during the discharge and pressure reduction process is avoided, thereby improving welding efficiency and quality stability.

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Abstract

The embodiment of the invention provides a welding method for a supercritical CO2 conveying pipeline pipe, and particularly relates to the technical field of long-distance pipeline welding. The welding method comprises the steps that machined grooves are assembled and then subjected to preheating treatment, root welding is conducted in a manual upward welding mode, and a root welding layer is formed; when the temperature of the root welding layer is within the designed temperature range, hot welding is conducted on the root welding layer in a manual upward welding mode, and a hot welding layer is formed; and when the temperature of the hot welding layer is within the designed temperature range, multi-layer and multi-pass filling welding is carried out above the hot welding layer in an automatic upward welding mode, and a filling layer is formed. And when the temperature of the filling layer is within the designed temperature range, cosmetic welding is carried out above the last filling layer in an automatic upward welding mode, a cosmetic layer is formed, and welding between the two sections of steel pipes is completed. By means of the welding method, the requirement of supercritical CO2 conveying for the low-temperature impact toughness of the ring welding joint is met.
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