A 680mpa grade reinforced flange high fatigue hot rolled automobile structure steel and its production method and application
By designing a low-C, low-Mn, Ti, and Nb composition and employing a precise controlled rolling and cooling process, a hot-rolled automotive structural steel with high strength, high porosity, and high fatigue performance was prepared. This solved the problems of high cost and poor process stability in existing technologies, achieving a balance between low cost and high performance.
CN122406112APending Publication Date: 2026-07-17PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
- Filing Date
- 2026-06-08
- Publication Date
- 2026-07-17
AI Technical Summary
Technical Problem
Existing high-expansion steels suffer from drawbacks such as high cost, difficulty in microstructure control, and poor process stability when trying to achieve high strength, high porosity, and high fatigue performance.
Method used
By employing a low C-low Mn-Ti-Nb composition design and combining precise heating, controlled rolling and cooling processes, quasi-polygonal ferrite and acicular ferrite microstructures were prepared. Strengthening was achieved through nano-(Ti,Nb)(C,N) precipitates, avoiding the addition of expensive alloying elements.
Benefits of technology
It achieves high strength of 680MPa, high porosity of λ≥83%, and high fatigue strength of ≥307MPa under R=-1 conditions, reducing alloy cost and improving process stability and performance uniformity.
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Figure CN122406112A_ABST
Abstract
本发明公开了一种680MPa级增强凸缘性高疲劳热连轧汽车结构用钢及其生产方法和应用，属于冶金技术领域。该钢化学成分(wt%)为：C：0.016%～0.024%，Si：≤0.04%，Mn：0.83%～0.95%，P：≤0.013%，S：≤0.003%，Als：0.025%～0.042%，Nb：0.015%～0.025%，Ti：0.060%～0.078%，N：≤0.0028%，Ca：0.0006%～0.0014%，且满足0.047%≤Ti‑3.43N‑1.5S≤0.070%和C‑(Ti‑3.43N‑1.5S) / 4‑Nb / 7.75≤0.005%。生产方法包括：RH强制脱碳；LF钙处理并采用低N海绵钛合金化；板坯1248~1260℃加热；终轧870~887℃；前段冷却；566~595℃卷取。本发明通过微低C、低Mn、Ti‑Nb复合微合金化设计及精准控轧控冷工艺，获得准多边形铁素体+针状铁素体+纳米析出相组织，无珠光体和马氏体，使钢带兼具680MPa级强度、≥83%扩孔率及≥307MPa疲劳强度(R=‑1)，成本低廉，适用于汽车轻量化结构件制造。
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