High fatigue performance cryogenic steel reinforcement and method of manufacture

By employing a low-carbon, high-vanadium, and high-nitrogen design and a specific rolling process, the prepared low-temperature steel bars have solved the problem of insufficient fatigue performance in existing technologies, achieving comprehensive performance of high strength, excellent low-temperature toughness, and good process applicability, making them suitable as key structural materials for LNG storage tanks.

CN122105245APending Publication Date: 2026-05-29ANGANG STEEL CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
ANGANG STEEL CO LTD
Filing Date
2026-03-05
Publication Date
2026-05-29

AI Technical Summary

Technical Problem

Existing low-temperature steel bars suffer from insufficient fatigue performance, poor strength-toughness matching, and low precision in microstructure control, making it difficult to meet the high strength and high fatigue performance requirements of LNG storage tanks in extreme low-temperature environments.

Method used

By adopting a low-carbon, high-vanadium, and high-nitrogen composition design, and combining the effects of V and N, the steel reinforcement is strengthened by the precipitation of second-phase particles and fine grain strengthening. By controlling the content of alloying elements and the rolling process, lamellar pearlite and tempered sorbite structures are formed, thereby improving the strength and toughness of the steel reinforcement.

Benefits of technology

The prepared low-temperature steel bars exhibit high strength, excellent low-temperature toughness and fatigue resistance under both room temperature and low temperature conditions, meeting the engineering application requirements of LNG storage tanks, and possessing high fatigue life and good weldability.

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Abstract

The present application relates to the technical field of metal material, in particular to a high fatigue performance cryogenic steel bar and a manufacturing method thereof. The high fatigue performance cryogenic steel bar is composed of the following chemical components with the weight percentage: C: 0.03%~0.06%, Si: 0.25%~0.45%, Mn: 0.9%~1.5%, P≤0.005%, S≤0.005%, Ni: 3%~4%, V: 0.15%~0.19%, N: 0.038%~0.05%, V / N is between 3~5, and the rest is Fe and inevitable impurities. The process flow is as follows: hot metal pretreatment, smelting, LF, VD, continuous casting, billet heating, rolling, and online water penetration. The produced LNG storage tank cryogenic steel bar has high strength, excellent low temperature toughness and high fatigue performance, can meet the construction requirements of large and super large LNG storage tanks, is suitable for the expanding LNG storage tank market and the increasingly improved engineering application requirements, and belongs to a high-end wire rod product with outstanding comprehensive performance and wide application prospect.
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