Rebar is the most important material in large-scale engineering structures, and its fine structure determines strength seismic resistance of rebar. The objective this study to investigate effect Nb content on microstructure mechanical properties high-strength anti-seismic rebar under condition thermal deformation. Gleeble-3800 simulator was used simulate continuous rolling process, which analyzed that precipitation behavior Scanning electron microscope (SEM), transmission (TEM) universal...

Abstract In this study, the immersion test, surface analysis, cross-section quantitative analysis and electrochemical were used to study influence of Nb/V on corrosion behavior high-strength anti-seismic rebar in marine environments. The results clarified that addition improved resistance rebar, thereby reducing rate improving stability layers. Firstly, promoted transformation unstable Fe oxyhydroxides stable layers thus increasing α/(β + γ) ratio, potential total impedance value. Secondly,...

This study investigates the effects of microalloying elements vanadium (V) and niobium (Nb), along with varying isothermal transformation temperatures, on microstructural evolution mechanical properties SWRH82B high-carbon pearlitic steel. Comprehensive characterization was conducted using optical microscopy, scanning electron microscopy (SEM), backscatter diffraction (EBSD), transmission (TEM). The results show that addition V alone or in combination Nb refines lamellar spacing, pearlite...

Thermal deformation has a significant influence on the microstructure of high-strength antiseismic steel. The effect hot experimental steel was studied by Gleeble-3800 thermal simulator. characterized metallographic microscope, microhardness, tensile test, field emission scanning electron backscatter diffraction, and high-resolution transmission microscope. results show that core test is composed polygonal ferrite lamellar pearlite. mainly ductile fracture. Tensile strength hardness increase...

Abstract Rebar is an important material in the major structural engineering, and its fine structure has a very effect on performance of rebar. In this work, Gleeble-3800 thermal simulator was used to simulate control final cooling temperature process explore precipitation behavior microalloying elements microstructure mechanical properties The electron backscatter diffraction (EBSD), high-resolution transmission microscope (TEM), universal tensile testing machine were characterize...

Abstract High-strength rebar plays a supporting role in large engineering structures due to its excellent performance. In this study, the effect of different isothermal time treatments (30, 60, 100, and 200 s) at 650°C on microstructure transformation mechanical properties rebars was investigated. The hot-rolling process simulated by Gleeble-3800 thermal simulator. microstructure, precipitates, high-strength were characterized scanning electron microscopy, transmission microscopy (TEM),...

High-carbon hardline steels are primarily used for the manufacture of tire beads both automobiles and aircraft, vanadium (V) microalloying is an important means adjusting microstructure high-carbon steels. Using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission (TEM), precipitation phases continuous cooled were characterized, content, carbon diffusion coefficient, critical temperature calculated. The results showed that as V content increased to 0.06 wt.%,...

Abstract Rebar is an extremely important building material. The cooling rate and the presence of niobium (Nb) element are key factors influencing overall performance rebars. In this work, high-strength rebar’s microstructure, precipitated phase, mechanical properties were characterized using scanning electron microscopy, transmission HVS-1000 hardness tester, MTS810 universal tensile testing machine. results showed that a shift in from 0.3 to 3°C·s −1 resulted noticeable changes...

Seismic anti-seismic rebar, as materials for supporting structures in large buildings, need to have excellent mechanical properties. By increasing the Nb content and controlling cooling rate, microstructure precipitation behavior of steel are adjusted develop seismic rebar with Scanning electron microscopy (SEM), backscatter diffraction (EBSD), transmission (TEM), a universal tensile testing machine were used characterize microstructure, phases, properties experimental steels. The results...

HRB500E rebar is a low-alloy high-strength steel with excellent mechanical properties and good plasticity but suffers from deficient corrosion resistance. This can be solved by adding trace elements, including rare earth elements. Herein, the corrosion-resistant behavior of was evaluated weightlessness testing electrochemical measurements, effects Ce on structural evolution product layer were investigated scanning electron microscopy (SEM), Electron Probe X-ray Micro-Analyzer (EPMA),...

In this study, SEM, AFM, TEM, XPS, and electrochemical tests are used to study the passivation behavior of chromium alloyed high-strength rebar in simulated concrete pore (SCP) solutions with different pH values. The results show that after SCP solution values, passivating film on surface primarily consists a layer nanoscale oxide particles, which makes passive exhibit p-n type semi-conductor, presents rhombohedral crystal structure. As value decreases, particles become denser, leads...

Abstract HRB500E seismic steel bars are mainly used in high-rise buildings near the zone. The influence of different niobium contents (0–0.023%) on microstructure and mechanical properties reinforcement was studied. Results showed that grain size ferrite between 3.6 8.3 μm when only V added. Meanwhile, as content increases, particles further refined. After adding niobium, contribution increased by 9%. addition significantly refined reinforcement. second-phase nano-elliptic precipitate is...

The research progress surrounding second-phase particle-induced corrosion has been expounded through extensive work, including local (pitting corrosion, crevice stress corrosion) of Al2O3, (RE)-AlO3, CaS, MnS, NbC, and other particles in microalloyed high-strength rebars. By summarizing the mechanism these rebars, this review further explores fact that play an inducing role which guiding significance for on induced

The effects of niobium and composite strengthening on the phase transformation characteristics precipitation behavior continuous cooling high-strength rebar during thermal deformation subsequent were investigated. results show that when rate was within 0.3–5 °C/s, ferrite pearlite occurred in experimental steels. Nb content increased to 0.062 wt.%, starting temperature decreased. Meanwhile, zone gradually expanded, narrowed with increase rate. When 1 bainite began occur, amount It found main...

Abstract The synergy between Nb/Ti strengthening and precise isothermal transformation temperatures has resulted in the optimal microstructure mechanical properties anti-seismic rebars. microstructure, precipitates, of experimental steels at different were characterized using scanning electron microscopy, transmission backscatter diffraction, universal tensile testing machine. As temperature decreased from 700 to 600°C, ferrite grain size, pearlite interlamellar spacing, carbon diffusion...

In this study, the surface analysis, cross-section analysis and electrochemical were used to explore formation mechanism of Nb contents on passive film high-strength anti-seismic rebar in simulated concrete pore solution. The passivation experiments confirmed that addition promoted stability compactness Nb-containing rebar, efficiency was stronger than CS rebar. Firstly, with decreases pH, increases outer layer mainly composed Fe oxides oxyhydroxides, inner oxides. Secondly, beneficial...