Fire resistant high strength low alloy steels

Assefpour-Dezfuly, M.; Hugaas, BA; Brownrigg, Allan

doi:10.1179/026708390790189920

Cited by 7 publications

(9 citation statements)

References 1 publication

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“…Their carbides also offer resistance to softening when the steel is exposed to fire. The chemistry of the present investigation differs from the previous studies (Assefpour-Dezfully et al 1990;Chijiwa et al 1993;Fushioni et al 1995) in the following ways: (a) the content of molybdenum and chromium is low, (b) low niobium and vanadium are used in microalloyed steels and (c) chromium without molybdenum has been used in TMT rebar.…”

Section: Steelcontrasting

confidence: 56%

“…In order to achieve this strength level, the steel chemistry and manufacturing process are closely controlled. Previous studies on microstructure and mechanical properties of fire resistant steels carried out by Chijiwa et al (1993) and Assefpour-Dezfully et al (1990) focussed on processing, structure and properties of fire resistant steels with different combinations of alloying elements. In the present investigation, the effect of lower alloying addition, particularly molybdenum, on the elevated temperature properties will be discussed which is important due to increasing alloy cost.…”

Section: Introductionmentioning

confidence: 99%

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Microstructures and properties of low-alloy fire resistant steel

Panigrahi¹

2006

Bull Mater Sci

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Microstructures and properties of weldable quality low-alloy fire resistant structural steels (YS: 287-415 MPa) and TMT rebar (YS: 624 MPa) have been investigated. The study showed that it is possible to obtain two-thirds of room temperature yield stress at 600°°C with 0⋅ ⋅20-0⋅ ⋅25% Mo and 0⋅ ⋅30-0⋅ ⋅55% Cr in low carbon hot rolled structural steel. Microalloying the Cr-Mo steel by niobium or vanadium singly or in combination resulted in higher guaranteed elevated temperature yield stress (250-280 MPa). The final rolling temperature should be maintained above austenite recrystallization stop temperature (~ 900°°C) to minimize dislocation hardening. In a quenched and self-tempered 600 MPa class TMT reinforcement bar steel (YS: 624 MPa), low chromium (0⋅ ⋅55%) addition produced the requisite yield stress at 600°°C. The low-alloy fire resistant steel will have superior thermal conductivity up to 600°°C (> 30 W/m⋅ ⋅k) compared to more concentrated alloys.

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Section: Steelcontrasting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Microstructures and properties of low-alloy fire resistant steel

Panigrahi¹

2006

Bull Mater Sci

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“…The first article relating to these steels was published in 1990, in the article Fire resistant high strength low alloy steels [1], presented by Assefpour-Dezfuly et al, although it made no reference to the term "FR steels".…”

Section: Fr Steels and Manufacturing Methodsmentioning

confidence: 99%

Study of historical developments in the use of fire resistant steels

García

Biezma

Cuadrado

et al. 2013

Materials at High Temperatures

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This paper presents a review of the most relevant articles on fire-resistant (FR) steels, as part of a research project at the University of the Basque Country (UPV/EHU) on the FR properties of steelstructures. An important characteristic of FR steels is that they maintain their mechanical properties at high temperatures better than the more widely used structural steels, mainly due to their special chemical composition and the thermal treatment used in their manufacture. The available information on FR steel tests has been analysed. All the data allow us to study the evolution of mechanical properties at different temperatures. We have, in particular, conducted a comparative evolution of the yield stress (YE) and the yield stress ratio (Ra) at different temperatures. A summary is also presented of the most important elements in their composition and the different manufacturing treatments of these steels and their influence on the initial YE and RA at different temperatures. For example, molybdenum and niobium improve the YE considerably at elevated temperatures. The alloy Cr-Mo-V-Nb is considered effective in FR steels and the use of boron is recommended, if an FR steelstructure is required to withstand temperatures higher than 700ºC and to decrease the percentage of carbon.In view of the temperatures associated with manufacturing treatments, it should be recalled that although accelerated cooling, such as quenching, increases YE at room temperature and at high temperatures, it reduces the Ra of these steels. The most effective thermal treatment is air cooling, although special attention should be paid to the influence of slab reheating and the finish rolling temperature.

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“…[ 15 ] In contrast to the wealth of data available for effects of the alloying elements and various microstructures on fire resistance, studies on the strengthening mechanisms and fire resistance of the low‐Mo (≤0.30%) Nb–V–Ti complex microalloyed steel are relatively scare. Some studies pointed out [ 16,17 ] that the reasonable microstructure strengthening and microalloying with Nb, V, and Ti are effective in improving the fire resistance of steels. Consequently, it has an important theoretical meaning and a wide practical value to research low‐Mo Nb–V–Ti complex microalloyed fire‐resistant steel.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties and Precipitation Behaviors of a Low‐Mo Nb–V–Ti Complex Microalloyed Fire‐Resistant Steel with Two Kinds of Microstructure

Li¹,

Zhang²,

Wang³

et al. 2021

steel research int.

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A new type of low‐Mo Nb–V–Ti complex microalloyed fire‐resistant steel is designed. Two kinds of controlled rolling and controlled cooling processes are employed to obtain the two steels with predominantly composed of fine‐grained proeutectoid ferrite (1#) and coarse‐grained full bainite (2#), respectively. The microstructures and precipitates of the experimental steels in room temperature and 600 oC are characterized by means of the scanning electron microscope (SEM), electron backscattered diffraction (EBSD), transmission electron microscope (TEM), and physicochemical phase analysis, and the strengthening mechanisms at room temperature and elevated temperature are quantitatively calculated and analyzed. The results show that the mechanical properties of the two steels are close to each other at room temperature. However, the fire resistance of bainite steel is much better than that of ferrite steel. Nanosized M(C, N) further precipitates from bainite at elevated temperature, which improves the stability of the bainitic structure and compensates for the loss of yield strength caused by the shear modulus decreased at high temperature. The grain refinement strengthening may not play a role at 600 oC in proeutectoid ferrite steel.

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Fire resistant high strength low alloy steels

Cited by 7 publications

References 1 publication

Microstructures and properties of low-alloy fire resistant steel

Microstructures and properties of low-alloy fire resistant steel

Study of historical developments in the use of fire resistant steels

Mechanical Properties and Precipitation Behaviors of a Low‐Mo Nb–V–Ti Complex Microalloyed Fire‐Resistant Steel with Two Kinds of Microstructure

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