Low yield ratio high toughness 9ni steel and short process preparation method thereof

By using microalloying design and a short-process online direct quenching method, the problems of long production cycle, high energy consumption, and high cost of 9Ni steel were solved, and the yield strength ratio and low-temperature toughness were synergistically optimized, producing high-performance steel plates for LNG storage tanks.

CN122105239APending Publication Date: 2026-05-29HEBEI DAHE MATERIAL TECH CO LTD +2
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
HEBEI DAHE MATERIAL TECH CO LTD
Filing Date
2026-01-22
Publication Date
2026-05-29

AI Technical Summary

Technical Problem

Existing 9Ni steel production technology suffers from problems such as long production cycle, high energy consumption, high cost, and difficulty in synergistically optimizing yield strength ratio and low-temperature toughness. Furthermore, traditional processes offer limited assurance of steel purity and surface quality, failing to meet the safety and economic requirements of LNG storage tanks.

Method used

A short-process technology combining microalloying design and direct online quenching (DQ) is adopted, including controlled rolling, online ultra-fast cold direct quenching and offline tempering. By controlling the chemical composition and process flow, 9Ni steel plates with a yield strength ratio ≤0.88 and an impact energy ≥180J at -196℃ are produced.

Benefits of technology

Significantly shorten the production process, reduce energy consumption and production costs, improve the low-temperature toughness and surface quality of steel plates, achieve synergistic optimization of yield strength ratio and low-temperature toughness, and improve the safety and economy of materials.

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Abstract

The application discloses a kind of low yield ratio high toughness 9Ni steel and its short process preparation method, belong to high-performance special steel manufacturing field.9Ni steel chemical composition is as follows according to percentage by mass: C:0.03~0.06%, Si:0.10~0.25%, Mn:0.50~0.80%, P≤0.003%, S≤0.001%, Ni:8.70~9.70%, Mo:0.08~0.15%, Ti:0.010~0.025%, Ca:0.0010~0.0030%, Alt:0.030~0.060%, N:0.003~0.006%, O≤0.0015%, the rest is Fe and inevitable impurity.Preparation method uses the short process technology of '' controlled rolling + online direct quenching + offline tempering'', and steel plate has high safety, high toughness and high quality, is suitable for LNG storage tank and other fields.
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