800MPa-grade HIC-resistant high-strength steel plate for large crude oil storage tank construction and preparation method thereof

By optimizing the chemical composition and process flow, 800MPa-grade HIC-resistant high-strength steel plates were prepared, solving the problem of insufficient HIC resistance in large crude oil storage tanks. This achieved a combination of high strength and excellent HIC resistance, making it suitable for large-scale industrial production.

CN122081815APending Publication Date: 2026-05-26SHANDONG IRON & STEEL CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
SHANDONG IRON & STEEL CO LTD
Filing Date
2026-03-09
Publication Date
2026-05-26

AI Technical Summary

Technical Problem

In the existing technology, the hydrogen-induced cracking (HIC) resistance of 610MPa grade high-strength steel plates in acidic storage environments containing H2S cannot be consistently met, which cannot satisfy the dual requirements of high strength and HIC resistance for large crude oil storage tanks.

Method used

The preparation method of 800MPa grade HIC-resistant high-strength steel plate is adopted. By optimizing the chemical composition and process flow, including converter smelting, LF refining, RH vacuum treatment, full-process argon-protected casting, two-stage controlled rolling with double stand and offline quenching and tempering treatment, the chemical composition and microstructure of the steel plate are controlled to improve the HIC resistance performance.

Benefits of technology

The prepared steel plate has a yield strength ≥700MPa, tensile strength ≥800MPa, elongation after fracture ≥19%, weld crack sensitivity index Pcm≤0.24%, carbon equivalent CEV≤0.50%, and excellent resistance to HIC, meeting the dual requirements of high strength and resistance to HIC for large crude oil storage tanks.

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Abstract

The invention discloses a 800MPa-grade HIC-resistant high-strength steel plate for construction of a large crude oil storage tank and a preparation method of the 800MPa-grade HIC-resistant high-strength steel plate. The steel plate comprises the following chemical components: 0.05 to 0.09 percent of C, 0.10 to 0.30 percent of Si, 1.10 to 1.50 percent of Mn, less than or equal to 0.008 percent of P, less than or equal to 0.0010 percent of S, 0.015 to 0.045 percent of Nb, 0.030 to 0.060 percent of V, 0.008 to 0.020 percent of Ti, 0.20 to 0.50 percent of Cr, 0.20 to 0.40 percent of Mo, 0.30 to 0.60 percent of Ni, 0.15 to 0.30 percent of Cu, 0.0010 to 0.0030 percent of Ca, 0.020 to 0.050 percent of Al, less than or equal to 0.0040 percent of N, less than or The preparation method comprises the steps of smelting, continuous casting, slab heating, rolling and heat treatment. The steel plate has high strength, high toughness, good weldability and excellent HIC resistance.
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