Post-fire mechanical properties of dual-phase advanced high-strength steel

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures Pub Date : 2025-01-31 DOI:10.1016/j.tws.2025.113038

Jia-Hui Zhang , Hong-Wei Li , Yixin Zhu , Ying-Min Hao , Hai-Ting Li

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引用次数: 0

Abstract

Fire-induced high temperatures significantly affect the microstructure and mechanical properties of advanced high-strength steel (AHSS). This study examines the mechanical properties of cold-rolled dual-phase AHSS after exposure to elevated temperatures, identifies the material's degradation trends, and quantitatively analyzes the relationship between grain size, phase transformation, and yield strength. Tensile coupons were extracted from thin-walled sheets and cold-formed C-sections, heated to 300 °C-1000 °C for soaking times of 15 or 60 min, and naturally cooled to room temperature. Tensile tests were conducted to obtain stress-strain curves as well as key mechanical properties after different fire exposure temperatures. Mechanical property degradation trends of high-strength dual-phase steel differ significantly from those of other high-strength steel. In the 600 °C to 1000 °C range, the strength of dual-phase steel drops from 600 °C to 700 °C, then recovers at higher temperatures. The yield strength of the dual-phase AHSS increases by 48.9 % from its lowest value at 700 °C between 800 °C and 900 °C, while the ultimate strength increases by 45.7 % in the same range. Moreover, longer exposure times led to more pronounced deterioration of mechanical properties. This study proposes a post-fire reduction factor prediction formula and a constitutive model for dual-phase AHSS based on different soaking times. Furthermore, microstructure observations of the dual-phase steel after fire exposure were conducted. A modified Hall-Petch equation, considering grain size distribution and phase transformation after fire exposure, accurately predicts post-fire yield strength, aligning well with experimental results.

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来源期刊

Thin-Walled Structures 工程技术-工程：土木

CiteScore

9.60

自引率

20.30%

发文量

801

审稿时长

66 days

期刊介绍： Thin-walled structures comprises an important and growing proportion of engineering construction with areas of application becoming increasingly diverse, ranging from aircraft, bridges, ships and oil rigs to storage vessels, industrial buildings and warehouses. Many factors, including cost and weight economy, new materials and processes and the growth of powerful methods of analysis have contributed to this growth, and led to the need for a journal which concentrates specifically on structures in which problems arise due to the thinness of the walls. This field includes cold– formed sections, plate and shell structures, reinforced plastics structures and aluminium structures, and is of importance in many branches of engineering. The primary criterion for consideration of papers in Thin–Walled Structures is that they must be concerned with thin–walled structures or the basic problems inherent in thin–walled structures. Provided this criterion is satisfied no restriction is placed on the type of construction, material or field of application. Papers on theory, experiment, design, etc., are published and it is expected that many papers will contain aspects of all three.