High Strength Steel Research Articles

Ion-selectivity of galvanic corrosion products formed in multi-material gaps under atmospheric corrosion conditions with anti-freezing salts

Several multi-materials, which are joints of high-strength steels and lightweight materials such as aluminum alloy and carbon fiber reinforced thermoplastic, were subjected to the cyclic corrosion test for simulating atmospheric corrosion of automotive bodies and outdoor exposure tests. The ion-selectivity of the corrosion products formed in the multi-material gaps was examined by a membrane potential measurement. The corrosion products of all examined joints showed anion-selectivity rather than cation-selectivity. Corrosion products formed in joint gaps were less effective in preventing the progression of galvanic corrosion, suggesting that sufficient atmospheric corrosion protection is required for the use of multi-materials.

Behavior of UHPC filled high-strength square steel tubular stub columns under combined flexural and axial loads

This study experimentally and numerically investigated the behaviors of UHPC-filled high-strength square steel tube stub columns with compact, noncompact and slender sections under combined flexural and axial loads. Eighteen tests were conducted, addressing the gap of limited tests on concrete-filled square steel tubular stub columns with noncompact or slender sections. Additionally, finite element analyses were developed and benchmarked for parametric studies. The results of tests and parametric studies show that (1) steel tube outward buckling and concrete crushing occurred at 1/4–1/2L of the compression zone; (2) the load-axial displacement curves organized into three phases: elastic, elastic-plastic, and recession phase; (3) the compressive strength increased with increasing tube thickness, concrete strength, and steel yield strength. The compressive strength decreased with increasing eccentric ratio and slenderness coefficient. Test and numerical results are utilized to assess the suitability of current design specifications for predicting compressive strength. The evaluation showed that neither GB 50936–2014 nor Eurocode 4 provided reasonable predictions of strength, while AISC 360–16 provided conservative predictions.

Microstructure and mechanical properties of low cost co-free high strength steel fabricated by plasma arc-based directed energy deposition

Arc-based directed energy deposition (DED) is characterized by high efficiency and excellent manufacturing flexibility, making it a promising choice for fabricating large structural components. High power density plasma arc-based directed energy deposition (PA-DED) was employed to fabricate high strength steel (HSS) component with a new Co-free welding wire. The microstructure and mechanical properties of the component were investigated in detail. The results showed that the matrix microstructure consisted mainly of martensite and ferrite. Austenite was observed in the bottom and middle samples, and the bottom sample exhibited the highest austenite content. All the samples in different regions exhibited a pronounced {100} 〈001〉 cube texture. The vertical samples had worse tensile properties than horizontal samples, which would be contributed to the interlayer bands and preferred orientation. The horizontal-middle samples demonstrated the highest tensile strength (UTS: 1207.8 ± 14 MPa, EL: 15.91 ± 1.03%). All deposited samples showed strong plastic deformation characteristics, illustrating that the new Co-free HSS components manufactured by PA-DED might replace conventional high-alloy HSS components for industrial applications.

Numerical Study and Design Method for Lateral Torsional Buckling of High-Strength Steel Beams

Given the increasing use of high-strength steels in building constructions, the stability design of high-strength steel beams has become a crucial consideration. However, the current standards of various countries are based on analyses and fittings derived from conventional steel, rendering them unsuitable for high-strength steel. Moreover, existing research indicates that these standards underestimate the ultimate load-bearing capacity of high-strength steel beams. A finite element model was established to investigate lateral torsional buckling in high-strength steel beams. The obtained results were then compared with test results from experiments conducted on Q460GJ and Q690 steel beams. The reliability and accuracy of the established finite element model were validated. Through parametric studies, the impact of depth-to-width ratio, boundary condition, and steel grade on the stability coefficient was evaluated. It was observed that at the same non-dimensional slenderness, an increase in the depth-to-width ratio or a reduction in support constraints led to a decrease in the stability coefficient. It should be noted that the steel grade had little effect on the stability coefficient. Comparisons with the current steel structure design codes, such as EN1993-1-1, GB50017-2017, JGJ/T483-2020, and ANSI/AISC360-22 revealed an underestimation of the stability coefficient for clamped high-strength steel beams under uniformly distributed loads. Based on finite element simulations, stability coefficients for high-strength Q460, Q690, and Q960 clamped beams were determined. Similar to the stability coefficient proposed in GB50017-2017 for the lateral buckling stability design of steel beams, a lateral buckling stability coefficient for high-strength steel clamped beams subjected to uniformly distributed loads was proposed.

Fuse replacement implementation by shaking table tests on hybrid moment-resisting frame

A seismic resilience enhanced structural system, called Hybrid Moment-Resisting Frame with Replaceable Energy Dissipation Angles (HMRF-REDA), is proposed with the advantage of cost-effective and easy replacement work. The system consists of energy dissipation bays (EDBs) featuring fuse connections and re-centering bays (RBs) constructed from high strength steel (HSS). The fuse connections are designed to concentrate damage on sacrificial and easy-to-repair elements in the presence of a concrete slab. The HSS members not only provide adequate load carrying capacity but also necessary re-centering capability essential for fuse replacement. In this research, shaking table tests were performed to investigate the seismic performance of HMRF systems and in particular, the feasibility of on-site fuse replacement within the complete structural system. The specimen was comprised of two parallel, three-story hybrid moment-resisting frames at a 1/2 scale. The results demonstrated that HMRF-REDA exhibited a multi-stage yielding sequence with damage restricted to the fuse elements for the expected deformation range. The HSS frame members were able to fully re-center the structure after it underwent an inner-story drift of up to 0.0235 rad. Furthermore, two on-site fuse replacement operations were successfully implemented within the structural systems, demonstrating the feasibility and ease of operation. The frames with replaced fuses exhibited similar elastic and inelastic performance when it experienced a preceding drift up to 0.0184 rad.

Characterization of Microstructure–Mechanical Properties Relationship in Dissimilar Resistance Spot Welding of the Advanced High-Strength Steel DP590 Steel to the Interstitial-Free Steel DC 06: EBSD Study

Characterization of Microstructure–Mechanical Properties Relationship in Dissimilar Resistance Spot Welding of the Advanced High-Strength Steel DP590 Steel to the Interstitial-Free Steel DC 06: EBSD Study

Understanding plasticity in multiphase quenching & partitioning steels: Insights from crystal plasticity with stress state-dependent martensitic transformation

This study develops a novel crystal plasticity (CP) model incorporating deformation-induced martensitic transformation (DIMT) and transformation-induced plasticity (TRIP) effect to predict the complex interplay between microstructural evolution and mechanical behavior in a third-generation advanced high-strength steel QP980. This model introduces phenomenological theory of martensite crystallography (PTMC) based TRIP theory and DIMT kinetics grounded on nucleation-controlled phenomenon. Notably, the DIMT model is improved by utilizing a geometric approach for calculating shear band intersections. A virtual multiphase representative volume element (RVE) based on the Voronoi tessellation is generated for the QP980 steel, which comprises ferrite, martensite, and retained austenite (RA). The study highlights how phase transformation affects mechanical properties, notably the strengthening from transformed martensite and the mechanical alterations in RA due to the TRIP effect. The DIMT kinetics dependent on stress states such as uniaxial tension (UT), uniaxial compression (UC), plane strain tension (PST), and equi-biaxial tension (EBT) are analyzed using the developed model. The role of microstructural surroundings on martensitic transformation is also examined. Furthermore, analysis under biaxial loading angles using the model reveals an asymmetric yield surface, with more pronounced changes in yield stress in the tensile region due to accelerated transformation behaviors, as opposed to the more gradual transformations in the compressive region. This study provides valuable insights into the deformation mechanisms of the third-generation advanced high-strength steels including relationship between plastic anisotropy, transformation kinetics, and microstructural evolution.

Experimental Investigation of Corrosion Behavior of Zinc–Aluminum Alloy-Coated High-Strength Steel Wires under Stress Condition

Experimental Investigation of Corrosion Behavior of Zinc–Aluminum Alloy-Coated High-Strength Steel Wires under Stress Condition

The effect of strain lag for the flexural enhancement of RC beams strengthened by HMRE under secondary load

This paper presents experimental, numerical and theoretical studies on damaged reinforced concrete (RC) beams strengthened with high-strength stainless steel wire rope (HSSSWR) meshes reinforced engineered cementitious composite (ECC), in order to evaluate the influence of strain lag caused by secondary load on the strengthening effect. Four-point bending tests were first performed to investigate the failure mechanism of HSSSWR meshes reinforced ECC (HMRE) strengthened RC beams under secondary load. Then the parameters were comprehensively studied by finite element (FE) simulation. The results show that even under secondary load, the HMRE can still exhibit good crack-control capacity on concrete and gave significant enhancement in the flexural performance of RC beams. The strain lag of the strengthening layer, which resulted in inadequate utilization of its strength, was intensified with an increase in the initial load level or reinforcement ratio of the longitudinal steel bars, but was mitigated as concrete strength, ECC thickness, reinforcement ratio of HSSSWRs, or HSSSWR ultimate strength increased. Finally, a calculating model was proposed for predicting the bearing capacity of the damaged RC beams strengthened with HMRE, considering strain lag caused by secondary load.

Forming Limits Prediction of Laminated SUS430/Al1050/SUS430 Composites and the Effect of Component Properties on Mechanical Performance

In this study, a constitutive model applied to predict the tensile properties and fracture behavior of well‐bonded multilayered metal composites is extended. The equivalent single‐layer model, as a convenient method, is introduced into finite‐element simulations by combining it with an improved Xue–Wierzbicki damage plasticity model that considers material anisotropy. The steel use stainless (SUS) 430/Al1050/SUS430 laminated sheet fabricated by cold rolling is selected as the research material. The quasistatic uniaxial tests and Nakazima tests are operated to verify the accuracy of the proposed method. The mean errors in tensile stress and fracture forming limit strains are 2% and 3%, respectively. A load‐sharing mixture rule is proposed to assess the effects of the volume fraction, strength coefficient, and hardening exponent of the constituent materials on the mechanical properties of the laminates. In the results, it is indicated that the laminate exhibits sufficient elongation and remains markedly enhanced in tensile strength, reaching 470 Mpa when the ductile Al layer is combined with the higher strength and hardenability steel layer. In this research, it is aimed to clarify the formability characteristics in laminated composites for optimal sheet configuration design and development.

Seismic response of RC short columns strengthened by high-strength stainless steel wire rope meshes reinforced ECC jacket

A novel strengthening scheme of high-strength stainless steel wire rope (HSSSWR) meshes reinforced engineering cementitious composite (ECC) jacket was used to strengthen the reinforced concrete (RC) short columns in this paper. The seismic performance of short columns after being strengthened was investigated, considering the changes in the strengthening scheme, and the spacing of lateral HSSSWRs. The failure mode, hysteresis behavior, envelope curve, ductility, energy dissipation, stiffness degradation, and strength degradation were introduced specifically based on the analysis of six full-scale short columns. The test results show a significant enhancement in the seismic performance of the strengthened short columns, especially in ductility and energy dissipation, which were increased by 49.4–98.4 %, and 149.3–713.2 %, respectively. The placement of HSSSWRs in ECC jacket proved to be effective in enhancing the strengthening effect of the jacket. A prediction model for the shear capacity of the strengthened columns was proposed using the Modified Compression Field Theory (MCFT), and the predicted results were in good agreement with the test results presented in this paper and in relative study.

Analysis of Strain Transfer Efficiency Coefficient of a Novel High-strength Steel Wire FBG Sensor

Analysis of Strain Transfer Efficiency Coefficient of a Novel High-strength Steel Wire FBG Sensor

Comparative performance analysis of straight and harped prestressing seven-wire strands: High-strength stainless steel vs. conventional carbon steel

This paper presents an experimental investigation into the utilization of high-strength stainless steel (HSSS) strands systems in prestressed bridges. The study delves into the effects of localized bent and harping of seven-wire HSSS strand systems under various harping angles and curvatures produced by the deviators. For comparison purpose, conventional carbon steel (CS) strands were also studied using the same experimental parameters. It was anticipated that CS strands would exhibit better performance due to its superior post-yied ductility. To closely mimic the state of practice in the precast plant, two types of deviators were designed and used in this investigation. A comparable harping capacity was observed for HSSS strands relative to CS strands, despite the CS strands exhibiting higher strain compared to the HSSS strands. Upon reaching their breaking load, necking of all seven wires was predominantly observed for HSSS, whereas the CS strands failed due to the fracture of only one or two outer wires. Due to the lack of ductility in the HSSS stand, it was expected to have the lower bent capacity, especially at higher harping angles. Despite the significant difference in post-yied ductility, the study revealed that both HSSS and CS strands exhibit similar performance. To further understand the similarity and difference in behaviour of these two materials, scanning electron microscopy (SEM) examinations were conducted on both HSSS and CS wires to visualize the bending effects on the microstructure level after bending the center wire at different angles.

Interaction and compatibility between steel and concrete of circular CFST stub columns with high-strength materials

To promote the application of high-strength-materials in concrete-filled steel tubular (CFST) columns, finite element modeling, and parametric analysis were conducted on circular CFST stub columns filled with normal-strength concrete (NSC) and ultra-high strength concrete (UHSC). For simulating properties of concrete under passive confinement, a three-dimensional constitutive model for NSC and UHSC was established, of which the stress-strain relation and evolution of dilation angle are both related to confining pressure and axial plastic strain. The model was verified by tests of CFHSST (concrete-filled high-strength steel tube) and UHSCFST (ultra-high-strength concrete-filled steel tube), demonstrating that the interaction between concrete and steel tube can be revealed correctly. Parameter analysis of CFST stub columns filled with NSC and UHSC was carried out, with the grade of steel tube covering from Q235 to Q890 and the D/t ratio ranging from 8.9 to 75. With the decrease of D/t ratio, the deformation capacity and post-peak performance of columns are improved. A recommended range of steel contribution ratio of UHSCFST was proposed for the consideration of cost and safety, which is 25% ∼ 63%. Based on the analysis of interaction between concrete and steel tubes, the compatibility of the two materials is recommended, of which the yield of steel tube occurs after contact with concrete and before the concrete reaches its peak strength. Besides, the formula in EC4 overestimates the load-bearing capacity of CFST stub columns with high-strength materials. Therefore, a modified formula was proposed that reduces the enhancement factor of concrete strength and enables a safer prediction of load-bearing capacity.

Experimental and numerical investigations of high strength steel unlipped channel sections under interior-two-flange loading

This paper presents laboratory tests, numerical simulations and web crippling design of high strength steel unlipped channel sections under interior-two-flange loading. An experimental programme comprising 10 test specimens (with six for grade S690 high strength steel and four for grade S960 high strength steel) was firstly implemented, and test results including failure modes, full load-deformation curves and ultimate loads were reported. Subsequently, finite element models were constructed and validated against the obtained test results, and then used to conduct supplementary parametric studies to widen the examined parameter ranges of high strength steel unlipped channel sections. Considering that relevant codified design rules are absent, the applicability of the design rules of EN 1993–1-3, EN 1993–1-5 and AISI S100 for normal strength steel unlipped channel sections to their high strength steel counterparts was evaluated against the obtained test and numerical results. It is shown that the resistance predictions from the codified design provisions were generally inaccurate and scattered. Hence, a modified AISI S100 design method and a slenderness-based design method were proposed and demonstrated to be accurate, consistent and reliable for the web crippling design of high strength steel unlipped channel sections under interior-two-flange loading.

Interactive buckling behaviour of Q420–Q960 steel welded thin-walled H-section long column

Considering the broad application prospect of high-strength steel (HSS) in engineering structure, and the limitations present in existing studies on interactive buckling of HSS welded thin-walled box-section long column, both test and finite element analysis were employed to investigate the interactive buckling behavior exhibited by 12 specimens fabricated from Q420–Q960 steels. The detailed analysis considered various aspects, including the failure mode, axial deformation, interaction of local and overall buckling deformation, and the ultimate bearing capacity. Observations revealed that the utilization rate of steel strength diminished with an escalation in both the plate width–thickness ratio and steel strength. An increase in the plate width–thickness ratio correlated with an earlier onset of local buckling, and the influence of steel strength was found to be negligible. More importantly, the limit of the plate width–thickness ratio for columns undergoing interactive buckling increased with a rise in column slenderness and decreased with an increase in steel strength. Taking into account the influence of column slenderness and steel strength, a novel calculation formula for determining the limit of the plate width–thickness ratio was derived. It is noteworthy that Eurocode 3 and JGJ/T 483–2020 were found too conservative for calculating the ultimate bearing capacity, while ANSI/AISC 360–22 was found suitable. Additionally, a calculation method for the ultimate bearing capacity of Q420–Q960 steel welded thin-walled H-section long column was proposed based on the direct strength method.

Performance Evaluation of PVD and CVD Multilayer-Coated Tools in Machining High-Strength Steel

Performance Evaluation of PVD and CVD Multilayer-Coated Tools in Machining High-Strength Steel

Precipitation Behavior and Strengthening–Toughening Mechanism of Nb Micro-Alloyed Direct-Quenched and Tempered 1000 MPa Grade High-Strength Hydropower Steel

Faced with the rapid development of large-scale pumped-storage power stations, the trade-off between the strength and toughness of hydropower steels in extreme environments has been limiting their application. The effects of Nb micro-alloying and direct quenching and tempering processes on the strengthening–toughening mechanism of 1000 MPa grade high-strength hydropower steel are studied in this paper, and the precipitation behavior of Nb is discussed. The results showed that only the 0.025Nb steel using the DQT process achieved a cryogenic impact energy of more than 100 J at −60 °C. Under the DQT process, a large number of deformation bands and dislocations were retained, refining the prior austenite grains and providing more nucleation sites for the precipitation of NbC during the cooling process. The DQT process has a more obvious local strain concentration, mainly focusing on the refined lath boundary, which indicates that the refinement of the microstructure also promotes the stacking of dislocations. The improvement in fine grain strengthening and dislocation strengthening by the DQT process jointly led to an increase in strength, resulting in a better combination of strength and toughness.

Analysis of rolling contact and tooth root bending fatigue in a new high-strength steel: Experiments and micromechanical modelling

To find materials that meet the future requirements of increasing load density in wind turbine gear structures, the commonly used reference material, 18CrNiMo7-6, and another high-strength steel were analysed. Their fatigue properties were studied through rolling contact fatigue (RCF) and gear tooth root bending fatigue (TRBF) tests. The reference steel exhibited better fatigue performance under RCF conditions compared to the new steel; however, it was outperformed by the new steel under TRBF conditions. This study aims to understand gear contact fatigue at the microscopic level, moving beyond the macroscopic focus that dominates current research literature. To establish the causal link between the varied fatigue performance observed in these materials, we proposed a multiscale modelling workflow based on crystal plasticity. This crystal plasticity framework is combined with the fatigue indicator parameter (FIP) to explore the fatigue resistance of materials subjected to RCF and TRBF conditions. Emphasis has been placed on the role of retained austenite (RA) in fatigue performance. Utilizing representative elementary volumes (REVs) generated based on statistically representative crystallographic features and measured size distribution of RA, we examined the effects of various RA levels on fatigue resistance. Our findings reveals that the fatigue damage accumulation is significantly influenced by the level of RA. Different fatigue damage accumulation behaviours were observed under RCF and TRBF conditions. These insights offer new perspectives on RA’s role in fatigue resistance and highlight its complex influence under varied loading conditions.

A strain components-based Mohr–Coulomb fracture criterion for proportional loading

Ductile fracture criteria are crucial in the application of elastoplastic materials like advanced high-strength steels, particularly due to their tendency to fail without significant localized necking. It is aimed to figure out the unified mechanism for ductile fracture and accurately describe it with phenomenological criteria. In this study, the effect of the stress triaxiality and the Lode parameter is analyzed mathematically. The maximum shear strain and the normal strain to fracture are emphasized in the proposed strain components-based Mohr–Coulomb fracture criterion particularly designed for plane stress states, and it is assumed that fracture occurs when the combination of the maximum shear strain and the normal strain reaches the critical value. It is then extended to describe fracture with the equivalent plastic strain and the normal strain to fracture. The experimental fracture data of AA 2024-T351 and the additively manufactured Ti-6Al-4V titanium alloy are used to verify the proposed models. A fracture forming limit diagram comprising forming limit curves calibrated from stress states under different stress triaxialities is proposed based on the proposed fracture criteria for plane stress states. This study shows that a strong correlation between the maximum shear strain and the normal strain to fracture has been observed, and it can be described piecewise-linearly. Besides, the orientation of the fracture surface under both tension (including plane strain tension) and compression (including plane strain compression) can be qualitatively explained by the Mohr’s strain circles. The results provide a new insight into the intrinsic deformation and fracture mechanism of materials that fail without severe localized necking.