Mechanical properties of High and Very High Steel at elevated temperatures and after cooling down

Abstract

High-strength steels (HSS) are produced using special chemical composition or/and manufacturing processes. Both aspects affect their mechanical properties at elevated temperatures and after cooling down, and particularly the residual strength and the ductility of the structural members. As HSS equates the design of lighter structural elements, higher temperatures are developed internally compared to the elements designed with conventional carbon steel. Therefore, the low thickness members, along with the severe effect of high temperature on the mechanical properties of the HSS, constitute to the increased vulnerability of such structures in fire. Moreover, the re-use and reinstatement of these structures are more challenging due to the lower residual mechanical properties of HSS after the cooling down period. This paper presents a review of the available experimental studies of the mechanical properties of HSS at elevated temperatures and after cooling down. The experimental results are collected and compared with the proposed material model (reduction factors) of EN1993-1-2. Based on these comparisons, modified equations describing the effect of elevated temperatures on the mechanical properties of HSS are proposed. Also, the post-fire mechanical properties of HSS are examined. A comprehensive discussion on the effect of influencing parameters, such as manufacturing process, microstructure, loading conditions, maximum temperature, and others is further explored.

Nondestructive Post-fire Damage Assessment of Structural Steel Members Using Leeb Harness Method

“…The natural cooling method (air cooling) is equivalent to a normalizing process for steel. The internal structure of the grain becomes finer, the mechanical properties are improved, and the hardness is slightly lowered [30].…”

Специфика Статистики Упругих И Деформационно-Прочностных Свойств Высокопрочных Волокон Полипропилена

“…д. ), поскольку для них удается достигнуть высоких значений прочности (σ = 2−6 GPa) [1][2][3][4][5] и модуля упругости (E = 230 GPa) [6], сопоставимых с характеристиками неорганических материалов [7][8][9][10][11][12][13][14][15][16]. Отличительной особенностью некоторых полимерных материалов (как правило, высокоориентированных) является то, что удельные характеристики их механических свойств, нормированные по плотности материала (ρ), являются рекордными по сравнению со всеми другими материалами.…”

Experimental study on post-fire mechanical performances of high strength steel Q460

“…Accordingly, HSS has been widely used in high rise buildings and long-span bridges (Kang et al, 2018a; Shi et al, 2014; Wang et al, 2014) and is attracting much attention from researchers to advocate its widespread applications. All past research studies about high strength steels have highlighted questions, which are of great interest, not only to the study of ultimate strength and buckling problems of HSS structures (Kang et al, 2019; Liu et al, 2019; Maraveas et al, 2017a, 2017b; Nie et al, 2018; Sajid and Kiran, 2019; Wang et al, 2017; Xiong and Liew, 2016; Xiong et al, 2016), but also to the study of performances of HSS structural members under extreme loading (Kesawan and Mahendran, 2018; Liu et al, 2014; Maraveas et al, 2017a; Qiang et al, 2015a, 2015b; Wang et al, 2020a).…”

“…If a building does not collapse during a fire, the post-fire evaluation and repair of the fire-exposed building require better understanding and awareness of the post-fire performances of its construction materials. Extensive research works were conducted in last decades to study the post-fire behaviour of different types of structural steels including high strength steels, hot-rolled and cold-formed steels, duplex stainless steels, marine steels and so on (Azhari et al, 2017; Chiew et al, 2014; Gunalan and Mahendran, 2014; Hai et al, 2018; Huang and Young, 2018; Kang et al, 2018b; Li et al, 2017, 2018a, 2018b; Liu et al, 2017; Lu et al, 2016; Maraveas et al, 2017a, 2017b; Qiang et al, 2012, 2013; Ren et al, 2020; Sajid and Kiran, 2019; Wang et al, 2015, 2020b; Xie et al, 2018; Yahyai et al, 2016; Yan et al, 2014; Zhang et al, 2020). However, research works on the post-fire performance of Grade 460 HSS, one of current most commonly used HSS with a nominal yield strength of 460 MPa, are still very limited.…”