Cold-drawn Steel Wires Research Articles

A mathematical model for the prediction of mechanical properties on ASTM A510/A853 cold-drawn hypoeutectoid steel wire after batch annealing

Annealed ASTM A510/A853 hypoeutectoid steel wire is a very useful and versatile material that finds its applications in the construction industry; this is mainly due to its mechanical properties, since this product can reach high ductility. In order to achieve the sought quality and homogeneity in this material, it is necessary to have a suitable control during operation. Important operational control parameters in batch annealing are: heating and cooling rates, holding temperature and cycle time. These parameters have a direct effect on the process, and it is essential to elucidate the way they impact in the final product. This work concerns the development of a mathematical model targeted at the prediction of mechanical properties in terms of the operational parameters, in the outer spirals of American Iron and Steel Institute/Society of Automotive Engineers (AISI/SAE) steel drawn wire coils after they have been subjected to batch annealing. The model addresses non-isothermically the involved phenomena that take place during the annealing process: recovery, recrystallization, and grain growth below and above Ac1. It predicts grain size, tensile strength, and yield strength values with very good accuracy.

Hydrogen resistance and trapping behaviour of a cold-drawn ferritic–pearlitic steel wire

Abstract The present work investigates the resistance of a progressively cold-drawn carbon steel wire against hydrogen embrittlement. In this study, analytical and numerical methods are used to determine the critical hydrogen content, the critical hydrogen ratio and the embrittlement indices of the different material conditions. The wire with the highest degree of cold deformation shows the highest critical hydrogen content and improved resistance against hydrogen embrittlement. At higher degrees of deformation, the material shows stronger hydrogen trapping, which improves in combination with a change in the lamellar spacing and orientation of the pearlite the resistance to hydrogen embrittlement.

Experimental study on seismic behavior of fabricated lightweight steel solid waste High-strength foam concrete composite wall

In order to actively implement the “dual carbon” goal and promote the popularization and application of green energy-saving prefabricated buildings in low-rise and multi-storey residential structures in villages and towns, a prefabricated light steel solid waste high-strength foam concrete composite wall was proposed. The wall is composed of high-strength foam concrete, cold-drawn steel wire mesh and cold-formed steel, which can realize the integration of load-bearing and energy-saving of wall components. The failure characteristics, hysteresis characteristics, bearing capacity and deformation performance, stiffness degradation and energy dissipation capacity of the wall specimens with different structures were analyzed through monotonic load and in-plane lateral cyclic loading test on three different wall specimens. The results show that under the action of cyclic load, the wall specimens with three different structures all have shear failure, and the wall specimens without cold-formed steel at the ends have low bearing capacity and poor seismic behavior. The bearing capacity and seismic behavior of the wall specimens with cold-formed steel at the ends were significantly improved, and the cold-formed steel, cold-drawn steel mesh, and high-strength foam concrete had good coordination performance. Considering the inherent characteristics of foam concrete, based on the existing specifications, the formula for calculating the shear bearing capacity of the prefabricated light steel solid waste high-strength foam concrete composite wall is given. The shear bearing capacity of wall members with different structures, different loading methods and different axial compression ratios are tested and calculated, and the calculated results of shear bearing capacity are in good agreement with the test results.

Correlation between Microstructures and Ductility Parameters of Cold Drawn Hyper-Eutectoid Steel Wires with Different Drawing Strains and Post-Deformation Annealing Conditions

The relationship between microstructures and ductility parameters, including reduction of area, elongation to failure, occurrence of delamination, and number of turns to failure in torsion, in hypereutectoid pearlitic steel wires was investigated. The transformed steel wires at 620 °C were successively dry-drawn to drawing strains from 0.40 to 2.38. To examine the effects of hot-dip galvanizing conditions, post-deformation annealing was performed on cold drawn steel wires (ε = 0.99, 1.59, and 2.38) with a different heating time of 30–3600 s at 500 °C in a salt bath. In cold drawn wires, elongation to failure dropped due to the formation of dislocation substructures, decreased slowly due to the increase of dislocation density, and saturated with drawing strain. During annealing, elongation to failure increased due to recovery, and saturated with annealing time. The variation of elongation to failure in cold drawn and annealed steel wires would depend on the distribution of dislocations in lamellar ferrite. The orientation of lamellar cementite and the shape of cementite particles would become an effective factor controlling number of turns to failure in torsion of cold drawn and annealed steel wires. The orientation and shape of lamellar cementite would become microstructural features controlling reduction of area of cold drawn and annealed steel wires. The density of dislocations contributed to reduction of area to some extent.

Effects of Wire Drawing and Annealing Conditions on Torsional Ductility of Cold Drawn and Annealed Hyper-Eutectoid Steel Wires

The effects of microstructural features on torsional ductility of cold drawn and annealed hyper-eutectoid steel wires were investigated. The patented wire rods were successively dry drawn to ε = 0.79 (54.7%) ~ 2.38 (90.7%). To examine the effects of hot-dip galvanizing conditions on torsional ductility, steel wires with ε = 1.95 were annealed at 500 °C for 30 s for ~1 h in a salt bath. In cold drawn wires, the number of turns to failure increased steadily, showing the maximum peak, and then decreased with drawing strain. During the post-deformation annealing at 500 °C, torsional ductility of steel wires decreased with annealing time, except for the rapid drop due to the occurrence of delamination for 10 s annealing. The decrease of the number of turns to failure would be attributed to the microstructural evolutions, accompanying the spheroidization and growth of cementite particles and the recovery of ferrite in cold drawn steel wires. From the relationship between microstructural evolution and torsional ductility, it was found that among microstructural features, the shape and orientation of lamellar cementite showed the significant effect on torsional ductility of cold drawn and annealed hyper-eutectoid steel wires.

Improving strength of cold-drawn wire by martensitic transformation in a 0.65 wt% C low-alloy steel

Ultrahigh strength can be obtained by cold drawing of high-carbon steel wire, but the strength heavily relies on the extent of cold-drawn deformation and it is difficult to produce ultrahigh strength steel wire with large diameter. In this study, a new method by combination of cold-drawing and martensitic transformation was reported to significantly improve the strength of cold-drawn steel wire. By using the new method, the strength of the steel wire can be increased to over 2.4 GPa, which is much higher than its corresponding original cold-drawn wire (less than 2.0 GPa), while sacrificing only a small ductility. By using electrochemical etching, transmission electron microscopy and X-ray diffraction, the prior austenite grain size and the microstructure of the martensitic steel wires was analysed. After the heat treatment, the large cold deformed steel wire with 8 pass drawing displays grains of 4.9 μm and dislocation-substructured martensite; while the small cold deformed wire with 6 pass drawing results in coarser grains and a mixture substructure of dislocation and twin in martensite. The results demonstrate that the extent of cold-drawn deformation has a great influence on grain refinement in the later heat treatment; grain refinement to less than 5 μm will lead to martensite substructure transition from twin to dislocation, and thus endows the martensitic steel wire moderate ductility. In addition, calculation indicates that precipitate hardening and dislocation strengthening contribute about 76.9% to the yield strength, and martensite lath boundary strengthening contributes about 18% to the yield strength.

Investigation of structural behavior of precast concrete pipe with single elliptical steel cage reinforcement

Reinforced Concrete Pipe (RCP) with single elliptical (SE) reinforcement offers cost savings and is permitted by Canadian and American standards. Yet, its use has not yet gained momentum primarily due to limited knowledge of its structural performance. This study explores the structural behavior of full-scale 1050 mm and 1200 mm diameter RCP reinforced with SE cold drawn steel wire cage under the three-edge bearing test. Experimental results show that, given similar amount of reinforcing steel at the tension zone of the inner face of the invert and obvert of the pipe, RCP with SE reinforcing cage meets lower equivalent class than that of RCP with conventional double reinforcing cage. The absence of a second layer of reinforcement in the SE pipes produced more brittle failure characterized by radial tension, followed by concrete slabbing. Increasing the steel reinforcement ratio improved the 0.3-mm crack load and ultimate load capacity up to a certain threshold, beyond which adding more steel did not enhance the results. Results indicate that RCP with SE reinforcement designed per current standards did not meet the specified 0.3-mm crack and ultimate load capacity. Hence, pertinent provisions in CSA A257.2 and ASTM C76 for RCP need to be updated with specific and more suitable guidance for single elliptical cage RCP.

Correlation of Strain Path, Texture, Twinning, and Mechanical Properties in Twinning-Induced Plasticity Steel during Wire Drawing.

The effect of changing the strain path on texture development, twin kinetics, and mechanical properties in twinning-induced plasticity steel was investigated to understand twinning behavior in more detail. Among the various plastic deformation processes, the wire drawing process was selected to achieve the aims of the study. Specimens of cold-drawn TWIP steel wire under the same effective strain but with different crystallographic textures were successfully fabricated using the effect of the wire drawing direction. Electron backscatter diffraction results showed that the drawn wires using both unidirectional (UD) and reverse-directional (RD) wire drawing processes were characterized as duplex fiber textures of major <111> and minor <100>. It was found that the RD wire had a higher fraction of <111> component at both the center and surface areas compared to the UD wire, because the metal flow of the RD wire was beneficial for the development of a <111> orientation. The pronounced <111> crystallographic orientation of the RD wire activated the twinning rate and geometrically necessary dislocation density, leading to an increase in strength but a decrease in ductility. The strain path is as important as the amount of strain for strengthening the materials, especially those that are deformed by twinning.

Computer Simulation of Micro-Mechanic in Pearlitic Steel Wire Drawing

Cold-drawn high-carbon steel wire with pearlite microstructure is one of the most popular raw materials for modern reinforcing ropes. Lamellae thinning, changes in interlamellar interface and metallographic texture, strain localization is the main property-forming phenomena in the wire drawing process. However, the experimental study of these phenomena dynamics is difficult and time-consuming. Drawing process of pearlitic steel wire was investigated. Behavior of pearlite colonies on the surface and the central layer of the wire were researched, based on the multiscale computer simulation. Cementite lamellae orientation in relation to the drawing axis, interlamellar spacing and shape of cementite inclusions were key factors. Regularities of the pearlite colonies reorientation, changing the shape and size of cementite lamellae and strain localization in the ferrite were established on the basis of FEM. It was established that the cementite lamellae, that are parallel to the drawing axis, had the maximum thinning. Interlamellar distance in pearlite colonies with such lamellae changed most intensively. Cementite lamellae, that are perpendicular to the drawing axis, are the most susceptible to fracture. It was found out that for certain values interlamellar distance this effect can be reduced. Intensive reorientation of pearlite colonies in relation to the drawing axis was observed in the case of their location at an angle to the drawing direction. At the same time, there was a significant bending of cementite lamellae and their susceptibility to fragmentation. Estimated values of the wire mechanical properties were compared with a real experiment. The simulation results were verified by metallographic analysis.

Evolution of microstructure and tensile properties of cold-drawn hyper-eutectoid steel wires during post-deformation annealing

Manufacturing temperatures of severely cold-drawn hyper-eutectoid steel wires are sufficiently high to influence the mobility of dislocations and alloy elements, thereby affecting the materials’ mechanical properties. Herein, we describe the evolution of microstructure and tensile strength of the as-drawn 3.45 GPa steel wire during post-deformation annealing for 30 min at 150−450 °C. Annealing at 150 °C raised the strength to 3.77 GPa by age-hardening through activation of dislocations pinning by carbon, while further temperature rising up to 450 °C caused a severe loss of strength. It was proved that annealing at 300 and 450 °C destabilizes the lamellar microstructure, promoting the formation of carbon-deficient (Fe,Mn,Cr)3C-type cementite particles with preferentially rounded and partially faceted hetero-interfaces. Annealing at 450 °C yielded the accumulation of Mn and Cr at the ferrite/particle interfaces, and their concentrations at the interfaces were dependent on the interface structure; i.e., lower concentrations at rounded interfaces (formed through capillarity–driven coarsening of the spheroidized cementite), and higher concentrations at faceted interfaces (that are initially existing in the as-drawn state). Our proof-of-principle observations, supported by thermodynamic calculations and kinetic assessments, provide a pathway for understanding the changes in microstructural and tensile properties during manufacturing of the hyper-eutectoid steel wires.

Optimization of the Fabrication of Cold Drawn Steel Wire Through Classification and Clustering Machine Learning Algorithms

The demanding deformations steel is subjected to during drawing may result in the breakage of the wire. The hypothesis of this research is that drawing failure is not a random event but can be predicted using a suitable approach. Machine Learning classification and clustering algorithms have been implemented to predict the probability of failure during drawing and to optimize the manufacturing conditions to reduce the failure rate. The following algorithms have been employed for classification: K-Nearest Neighbors, Random Forests and Artificial Neural Networks. The reduced value of the rejection rate implies that classification must be carried out on an imbalanced dataset. For this reason, resampling methods (undersampling, oversampling and SMOTE) and specific scores for imbalanced datasets were used. It was possible to obtain a qualified Random Forest classifier which provided satisfactory scores (ROC AUC of 0.824 and an average precision of 0.604 in the test dataset). This tool allows the heats with a higher probability of undergoing any breakage during drawing to be detected, thus improving the final quality of the product. K-means clustering (K = 4) has been successfully used in this study to identify those manufacturing conditions that minimize the number of breakages during drawing. The results of the clustering analysis show that the rate of heats undergoing failure may be reduced by a factor of 2.5.

Failure analysis of spring of hydraulic operated valve

Abstract The breakage of spring of a valve causes the non functionality of a hydraulically operated system which pours steel into tundish (controls the flow of steel before putting into a caster) in a steel manufacturing plant. The valve is operated with two springs of diameter 0.3 mm among which one was broken. The spring failed after 5 years of service which had expected life of 10 years. The fracture surface under SEM showed striations confirming fatigue failure. The chemistry of the spring was confirmed to be o be a plain high carbon steel consistent with the requirements of ASTM A228 “Steel wire,Music quality” which is a cold drawn steel wire for mechanical spring. The microstructural analysis showed crack associated with scale and crow feet. The presence of crow feet like surface defect acted as stress concentration for fatigue crack initiation. The valve spring activated100 times per hour causing fatigue loading of the spring. The etched condition shows drawn pearlite typical structure of cold drawn spring and hardness was also found to be satisfactory. The presence of crow feet surface defect came from the wire drawing stage due to insufficient lubrication and considered to be manufacturing defect. The inspection of a spring this kind for critical applications should be robust to avoid future failures

Effects of Alloying Elements, Si and Cr, on Aging and Delamination Behaviors in Cold-Drawn and Subsequently Annealed Hyper-eutectoid Steel Wires

The effects of alloying elements, Cr and Si, and the conditions of hot-dip galvanizing on the aging behaviors and their related tensile and torsional properties in cold drawn hyper-eutectoid steel wires were investigated. The Cr and Si additions were found to increase tensile strength, but decrease the limit of drawing strain without delamination in cold drawn steel wires. The Cr and Si additions encouraged the suppression of age hardening and age softening during annealing. The increased amount of deformation in cold drawn steel wires made age hardening occur at the lower annealing temperature and shorter annealing time, and expanded the delamination region to high temperature during annealing. The additions of Cr and Si did not show the noticeable improvement of tensile strength without delamination in cold drawn steel wires, but increased the upper limit of tensile strength without delamination in cold drawn and annealed steel wires.

Effects of environmental factors on stress corrosion cracking of cold-drawn high-carbon steel wires

Premature failure of cable bolts due to stress corrosion cracking (SCC) is a phenomenon that has reported to occur in underground environments. This paper presents an experimental study to determine the impacts of environmental factors on SCC in high-carbon steel cable bolts used in ground support system. The service life of the wire strands was measured under a range of accelerated SCC conditions using three- and four-point loading jigs. Fractographic analyses of the fracture surfaces of the failed wires displayed typical features indicating that hydrogen embrittlement was involved in SCC in these tests. It was shown that the presence of hydrogen sulphide is more critical than its concentration in SCC. The pH and level of applied stress were determined to have a direct impact on the occurrence of SCC. The deflection angle of the crack path was observed to be an inverse polynomial function of the applied stress level in the wire. This demonstrated the significance of the stress level on the fracture mechanism of cable bolts. Furthermore, the use of a protective galvanised coating on cable bolts was found to be a promising countermeasure against SCC. The results of this study provide detailed insight into the environmental factors involved in SCC of high-carbon steel wires and can be further used for setting guidelines for assessment of environments which cause susceptibility to SCC.

Initiation and propagation of fatigue cracks in cold-drawn pearlitic steel wires

In this paper the important role of manufacturing by progressive cold drawing on initiation and propagation of fatigue cracks in cold-drawn pearlitic steel wires is addressed by analyzing the initiation (from surface defects) and propagation of fatigue cracks in two pearlitic steels with very different cold drawing degree or cumulative plastic strain (and the subsequent very distinct microstructural arrangement): a hot rolled pearlitic steel bar and a commercial high-strength cold-drawn prestressing steel wire to be used asa component of prestressed concrete in structural engineering. Experimental results show that the initiation of fatigue cracks in pearlitic steels takes place at the location of small surface defects, many of them in the form of localized damage in the area of material surface (in the case of hot rolled bar) or voids created by tearing during drawing due to the existence of particles near the wire surface (in the case of the cold drawn wire). In both materials, fatigue cracks are mostly transcollonial and tend to fracture pearlite (ferrite/cementite) lamellae, so that different micro-mechanisms of fatigue damage appear in the material such as non-uniform crack opening displacement, micro-discontinuities, branchings, bifurcations and frequent local deflections, all creating a sort of microstructural roughness in the fatigue crack path that is different in the hot rolled bar and in the cold drawn wire, thereby determining their distinct fatigue performance.

Cathodic polarization behavior of the structural steel wires under different prestressing conditions

Cold-drawn structural steel wires prestressed to different levels and cathodically polarized at various potentials were investigated using electrochemical techniques and slow strain rate tests. The potentiodynamic polarization revealed that prestressing enhances the active anodic dissolution of the structural steel wires. The corrosion current density and corrosion potential were observed to vary with prestressing levels applied to the structural steel wire specimens. The structural steel wire prestressed to 80% of its original tensile strength and cathodically polarized at −1500mV exhibited the highest current densities and lowest corrosion potentials after potentiodynamic polarization, which indicate that the above prestressing and cathodic polarization conditions lower the corrosion resistance of the material. Moreover, the tensile results show that the structural steel wire prestressed to higher levels and cathodically polarized at lower potentials was more susceptible to degradation of the tensile properties. The structural steel wire prestressed to 80% level and cathodically polarized at a potential of −1500mV exhibits the lowest UTS and ductility. The tensile fracture surfaces of the steel wires prestressed and cathodically polarized under above conditions exhibit mostly quasi-cleavage brittle fracture character. Furthermore, the brittle regions were observed to increase with increasing the prestressing levels and decreasing the cathodic polarization potentials applied to the structural steel wires.

Residual stress redistribution induced by fatigue in cold-drawn prestressing steel wires

In this paper the evolution of diverse residual stress states (similar to the ones produced after a cold drawing process) during several fatigue loading schemes is analysed. Thus, numerical simulations by finite element method were carried out applying diverse fatigue loading schemes to several cold drawn wires with a residual stress state associated. Numerical results reveal the key role of plastic strains produced by fatigue loading causing a redistribution of the residual stress when tensile stresses are placed at the wire surface. However, a negligible effect is obtained for wires with a compressive residual stress associated.

Analysis of Pearlitic Cold Drawn Steel Wire

The effect of microstructure on the mechanical properties of cord steel wires was investigated. Material properties and damage behaviours were identified. Metal cord, for reinforcing articles of an elastomeric material, such as tires, conveyor belts and so on of the single strand type, in particular made up of a plurality of 3, 4 or 6 wires, where in the said wires are twisted together loosely. The metal cord characterized by the fact that the diameter of the individual constituent wires varies between 0.12 and 0.30 mm. Rm tested cord wire was max. 2 946 MPa. Fracture surfaces cords steels were observed.

Residual Stress Analysis of Cold-drawn Pearlite Steel Wire Using White Synchrotron Radiation

Residual Stress Analysis of Cold-drawn Pearlite Steel Wire Using White Synchrotron Radiation

Hall–Petch k dependencies in nanopolycrystals

Measurements at nanopolycrystal grain sizes of the Hall–Petch plastic flow stress dependence on the reciprocal square root of polycrystal grain diameter occasionally fall short of expectations. The present report reviews experimental and theoretical aspects of such behaviours for a number of metal systems. Comparison with the results on copper had led to prediction on a dislocation pile-up mechanics basis of an even stronger grain size dependence that is now shown to carry over to explanation of similar results reported recently for cold-drawn eutectoid steel wires. In the current review, emphasis is given on additional important results achieved on the production of nanoscale zinc and tungsten carbide materials by Professor Jay Narayan and colleagues at North Carolina State University.