High Carbon Steel Wire Research Articles

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.

The Analysis of Force Parameters in Drawing Process of High Carbon Steel Wires in Conventional and Hydrodynamic Dies

AbstractThe paper analyzes force parameters in the process of multistage drawing of steel wires in conventional and hydrodynamic dies. The drawing process of the wire rod with a diameter of 5.5 mm for wires with a diameter of 1.70 mm was performed in 12 drafts with the usage of the multistage drawbench Koch KGT with the speed range of 5-25 m/s.Modern software of multistage drawbenches allows direct reading of many parameters during the drawing process, including drawing power. The force and drawing stress in each drafts were determined relying on experimental measurements. A complement to the research was a theoretical analysis of the drawing process. The results of the theoretical studies were compared to those obtained by experiment.The significant impact of the drawing speed on the force parameters of the drawing process in conventional and hydrodynamic dies was demonstrated. Depending on the real conditions of the drawing, ie. temperature, friction and lubrication, enhancing the drawing speed can result in both an increase and a decrease in drawing stress.

Effects of drawing strain and post-annealing conditions on microstructural evolution and tensile properties of medium- and high-carbon steels

Variation in the microstructure and tensile properties with the warm drawing strain and subsequent annealing of 0.45 wt% C (45C) medium-carbon steel and 0.82 wt% C (82C) high-carbon steel was investigated. The morphology and size of ferrite and pearlite changed considerably with applied strain during drawing and with annealing temperature and time, which made the tensile properties of the drawn steels vary considerably. With increasing drawing strain to ~2.5, the yield strength increased significantly from 393 to 1332 MPa for the 45C steel and from 673 to 1876 MPa for the 82C steel; this was attributed mainly to the strain hardening caused by severely deformed ferrite and/or enhanced particle hardening caused by cementite segmentation. During annealing of heavily drawn steels, ferrite grain growth and coarsening of broken cementite particles occurred simultaneously, which caused effective recovery of the ductility of severely drawn steels. These results demonstrate that the tensile strength and elongation of medium- and high-carbon steel wires can be tuned considerably by controlling the extents of drawing and annealing, thereby widening their applicability and facilitating their manufacture to match their mechanical properties to each application.

Optimization of Lead Patenting Process for High Carbon Steel Wires

The optimization of lead patenting heat treatment process of high carbon steel wires is done using Taguchi methodology. The experiments have been carried out on an electric powered furnace in industrial conditions. The L18 orthogonal array is used for optimization. This array consists of four input process parameters, i.e., type of steel, wire diameter, lead bath temperature and transformation time. The responses of lead patenting process are ultimate tensile strength (UTS), torsion strength (TS) and reduction in area (RA) of patented wire. The analysis of variance is applied to study the contribution of input process parameters in lead patenting process. The multiple regression equations are formulated for predicting values of UTS, TS and RA for a set of input process parameters. The optical microscopic images of all samples have been evaluated for percentage of pearlite phase in lead patented wires using software. The results of optical microscopic images analysis are compared with results obtained from Taguchi technique.

Influence of the Manufacturing Process on Defects in the Galvanized Coating of High Carbon Steel Wires.

This study is a detailed failure analysis of galvanized high carbon steel wires, which developed coating cracks during the torsion test performed as a quality control at the end of the manufacturing process. Careful visual inspections showed that the cracks are already present in the coating before the torsion test. In order to explain the origin of these cracks, systematic metallographic investigations were performed by means of optical and scanning electron microscope on both the wires and the rods that have been cold drawn to produce the wire. The chemical composition of the galvanized coatings was evaluated by means of energy dispersive spectroscopy. Micro bidimensional X-ray diffraction experiments were also performed to measure the residual stresses in the galvanized coating. The results showed that the failure is related to two main factors: the relatively high content of silicon in the steel and the unsuitable cooling rate of the rods at the exit from the galvanizing bath. The mechanism proposed to explain the origin of the defects was supported by Finite Elements Methods simulations and verified with in-plant tests. The proper countermeasures were then applied and the problem successfully solved.

Ductility Improvement of High Carbon Steel Wire by Alternate Wire Drawing

High carbon steel wires, due to their high mechanical strength and high fatigue characteristics, have been widely used in industrial products such as bridge cables and steel cords for tires. To produce wires that match the requirements for those purposes, wire drawing process is used. However, after the processing, tensile strength of the wires increases, but ductility decreases due to the shear deformation near the wire surface. In this study, we examined ductility improvement methods of high carbon steel wires and as a solution we suggest a method of processing called “alternate wire drawing”. The next step was to determine the usefulness of alternate wire drawing for increasing the ductility of the wires. Firstly we studied the total equivalent strain and the change of the shape of elements for each drawn wire by FEM analysis before testing. It was determined that in the case of alternate drawn wire the deformation of the elements was small also alternate wire drawing method is inhibiting the increase of total equivalent strain on wire surface. In case of tensile testing of drawn wire, we examined the mechanical properties of each wire drawing method and compared them. By doing this test we understood that in the case of alternate drawing there is a significant increase of breaking strain and drawing rate. We also have done torsion test to confirm the ductility of conventional wire drawing and alternate wire drawing. In case of conventional wire drawing method (Total reduction 91.7%) delamination appeared, however alternate wire drawing method (Total reduction 91.7%) there was no delamination. In addition, in case of total reduction of 97.2%, alternate drawn wire increases 20% more its torsion characteristics, than conventional drawn wire. And we also studied the changes of the crystal grain of drawn wire by EBSD (Electron Back Scatter Diffraction Patterns). We found out that grain size was shrunk by conventional drawn wire due to share deformation and for alternate drawn wire we confirmed that it was possible to inhibit the grain shrinking by 15% compared to the conventional drawing method. As a conclusion we found out that, by using alternate wire drawing method it is possible to improve the ductility of high carbon steel wires with the high tensile strength.

Improvement of Ductility with Maintaining Strength of Drawn High Carbon Steel Wire

The effect of areal reduction for one pass on mechanical properties of high carbon steel wire drawn using wet-type non-slip drawing machine was investigated. The wires of 0.443 mm in diameter with carbon 0.98% were drawn to 0.06 mm in diameter by reducing the sectional area of the wire by 14 % and 27 %. Tensile strength increased monotonically with increasing drawing strain and there were very few differences of tensile strength by pass schedule. Elongation had the minimum value at 2.5 of drawing strain and reduction of area also had the maximum value at 1.2 of drawing strain. Elongation and reduction of area were improved in the region of drawing strain more than about 3 by decreasing areal reduction for one pass. Therefore, the wire can be drawn with maintaining strength and ductility under small areal reduction for one pass at latter pass regardless of areal reduction at former passes.

The High Speed Wire Drawing Process of Steel Wires under Fluid Frictions Conditions

The essential purpose of the work was to determine the phenomena that occur in multipass wire drawing process of high carbon steel wires with high speed in hydrodynamic dies and to assess their influence on moulding the wire properties after the drawing process. The multiparameter analysis of the issues has involved the theoretical dissection of the phenomena arising in high speed wire drawing process in hydrodynamic dies with the usage of the finite element method supported by the experimental multipass drawing process in industrial conditions. On the basis of numerical analysis the influence of drawing speed on wire temperature was estimated. For final wires the investigation of mechanical properties, topogrhaphy of wire surface, the amount of lubricant on the wire surface, the pressure of lubricant in hydrodynamic dies were determined.

Effect of Stress-Strain State during Combined Deformation on Microstructure Evolution of High Carbon Steel Wire

It is shown that new methods of severe plastic deformation design require combining different methods of plastic deformation. As for carbon steel wire, using drawing as a basic operation is obvious. The combination of drawing with bending and twisting was estimated by the stress-strain uniformity complex. It allows choosing the deformation processing conditions which ensure the uniform stress-strain state in each point of the carbon steel wire cross section. Based on such combination, a new method for manufacturing of semi-products with ultra fine grain structure by drawing with torsion was developed. The combination of wire drawing in two consecutively arranged dies with simultaneous bending and torsion allows achieving complex stress-strain state of the processed metal and ensure the share stresses. Metallographic investigation shows that such scheme of combined plastic deformation provides the uniformity of metal microstructure in its cross section.

Corrosion of Carbon Steel Wire Roads Containing Various Sulfur Content in Sour Solutions

High strength carbon steel wire roads have been widely used in armor cables for offshore oil drilling plants. However, the materials can undergo some corrosions and hydrogen related damages such as hydrogen induced cracking (HIC) and sulfide stress cracking (SSC). In particular, it has been reported that HIC is highly influenced by content of MnS containing inside the steels. However, effects of sulfur content on the corrosion of carbon steel wire rod have scarcely been reported systematically. In this study, the effects of sulfur and propagation of corrosion in carbon steel wire rod were investigated in sour solutions with various pH. The carbon steel wire rods containing various sulfur content were used. All electrochemical tests were conducted using three-electrode system with a saturated calomel electrode (SCE) as the reference electrode and a Pt wire as the counter electrode. In addition, acetic acid based solution containing 95% CO2 and 5% H2S were used to adjust pH in the range of 2.5-6.5 at the room temperature for corrosion tests. Before testing, the carbon steel wire words were polished by abrasive papers and then washed with ethanol, and deionized water. The overall corrosion behaviors and corrosion rate of the samples were analyzed using potentiodynamic tests. In addition, the HIC characteristic of the steels was investigated by immersing the samples in the solution followed by observing the crack propagation inside the samples. Surface morphologies of the samples after tests were also observed by optical microscope (OM) and scanning electron microscope (SEM). The corrosion current densities (icorr ) of carbon steel increased with the increasing in sulfur contents in the steels. Further, from the polarization curves, it is observed that cathodic current density increased with sulfur content in steels. It is noticeable that the anodic current density rarely changes. This result indicates that the cathodic hydrogen evolution process on the surface of the steels was promoted by S content inside the steels. In addition, the samples without applied stress showed the internal macro-cracks in cross sections in pH 2.5~5.1, while only small micro-cracks were found in solution pH 5.1~6.5. The length of crack increased with increasing sulfur content except in the solution with pH 5.1~6.5. In particular, the micro-cracks by HIC appeared to initiate around inclusions. Some tracing of the cracks will be shown in this presentation.

高炭素鋼極細線の機械特性評価方法と伸線条件最適化による強化

高炭素鋼極細線の機械特性評価方法と伸線条件最適化による強化

Electromagnetic‐Thermal Modeling of Induction Heating of Moving Wire

The strength in a high carbon wire is attributed to the pearlitic microstructure, which is required for ease of wire drawing. During cold drawing of high carbon steel wires, residual stress develops which has to be relieved in order to obtain the desired mechanical properties. To achieve this, the wire is passed through a closed loop online an induction furnace at a particular speed in order to heat it to a uniform temperature range. This research work presents the electromagnetic‐thermal modeling of the induction heating of a moving wire based on the finite element method using the software package, COMSOL MultiphysicsTM. The furnace had a complicated geometry for the coils and this is, perhaps, for the first time an exhaustive study which is being reported. A unique grid generation technique was developed considering the skin effect. This work is aimed at enabling modeling of the process and will in turn be useful when defining individual parameters affecting the temperature distribution in a component, subjected to induction heating. The temperature distribution in the work piece depends primarily on parameters like coil position, line speed, frequency of the current, thermal and magnetic properties of the work piece, and so on. The impact of power supply frequency and line speed were studied during the heating of the moving wire (workpiece). An in‐situ customized furnace of lower capacity was developed to carry out the validation experiments. The present modeling results are validated with online plant trial data and found to be in good agreement. Finally, the desired mechanical property achieved during trials was confirmed through tensile testing.

Investigation of mechanical properties of cryogenically treated music wire

It has been reported that treating music wire (high carbon steel wire) by cooling to cryogenic temperatures can enhance its mechanical properties with particular reference to those properties important for musical performance. We use such wire for suspending many of the optics in Advanced LIGO, the upgrade to LIGO—the Laser Interferometric Gravitational-Wave Observatory. Two properties that particularly interest us are mechanical loss and breaking strength. A decrease in mechanical loss would directly reduce the thermal noise associated with the suspension, thus enhancing the noise performance of mirror suspensions within the detector. An increase in strength could allow thinner wire to be safely used, which would enhance the dilution factor of the suspension, again leading to lower suspension thermal noise. In this article, we describe the results of an investigation into some of the mechanical properties of music wire, comparing untreated wire with the same wire which has been cryogenically treated. For the samples we studied, we conclude that there is no significant difference in the properties of interest for application in gravitational wave detectors.

The Assessment Of The Structure And Properties Of High-Carbon Steel Wires After The Process Of Patenting With Induction Heating

Abstract One of the most important types of heat treatment that high-carbon steel wires are subjected to is the patenting treatment. This process is conducted with the aim of obtaining a fine-grained uniform pearlitic structure which will be susceptible to plastic deformation in drawing processes. Patenting involves two-stage heat treatment that includes heating the wire up to the temperature above Ac3 in a continuous heating furnace (in the temperature range of 850÷1050°C) followed by a rapid cooling in a tank with a lead bath down to the temperature range of 450÷550°C. The patenting process is most significantly influenced by the chemistry of the steel being treated, as well as by the temperature and the rate of heating and cooling of the wire rod or wire being patented. So far, heating up to the austenitizing temperature has been conducted in several-zone continuous gas-fired or electric furnaces. Recently, attempts have been made in a drawing mill to replace this type of furnace with fast induction heating, which should bring about an energy saving, as well as a reduced quantity of scale on the patented wire. This paper presents the analysis of the structure and mechanical properties of wires of high-carbon steel with a carbon content of 0.76%C after the patenting process using induction heating for different levels of the coil induction power.

The Analysis of the High Speed Wire Drawing Process of High Carbon Steel Wires Under Hydrodynamic Lubrication Conditions

Abstract In this work the analysis of the wire drawing process in hydrodynamic dies has been done. The drawing process of φ5.5 mm wire rod to the final wire of φ1.7 mm was conducted in 12 passes, in drawing speed range of 5-25 m/s. For final wires of φ1.7 mm the investigation of topography of wire surface, the amount of lubricant on the wire surface and the pressure of lubricant in hydrodynamic dies were determined. Additionally, in the work selected mechanical properties of the wires have been estimated. It has been shown that in the drawing process under hydrodynamic lubrication by drawing speed of 25 m/s the phenomena of uncontrolled formation of the surface and the diameter of the wire appears, and in the process the compressive stresses eliminating cracks on the wire surface occur, causing further smoothing. The wires drawn hydrodynamically in speed of 25 m/s, besides clearly worse properties compared to the wires drawn hydrodynamically at speeds in the range of 5 to 20 m/s, also exhibit large dimensional variations.

Analysis of industrial conditions during multi-stage cooling of C70D high-carbon steel wire rod

Abstract An analysis of the parameters of multi-stage controlled strip cooling during the process of rolling of 5.5 mm-diameter C70D high-carbon steel wire rod has been made in this publication. Investigations included also the analysis of the flow rate of the cooling medium and its pressure in the devices for accelerated and controlled cooling of the strip directly in the rolling line, as well as in the STELMOR line. The investigations carried out within the study have determined the cooling capacity of the accelerated strip cooling devices for specific (preset) cooling conditions. The scope of the investigations also encompassed the analysis of the effect of the employed cooling conditions on the temperature distribution and on the properties and microstructure of the steel studied. Moreover, physical modeling of the currently applicable technology of rolling the investigated steel grade was also performed.

NiTi porous structure with 3D interconnected microchannels using steel wire spaceholders

NiTi porous structures with fully 3D interconnected microchannels were created by a powder-metallurgy method using steel wires as spaceholders. Prealloyed NiTi powders were near-fully densified by hot pressing within a high carbon steel wire scaffold, which was then electrochemically dissolved. This resulted in a regular 3D network of orthogonally interconnected microchannels with ellipsoidal cross-sections with 60% volume fraction. The measured elastic stiffness of 14GPa compares well to porous and composite models, as well as finite element modeling despite varying geometry and deformation model assumptions. The structure, which is martensitic at room temperature, exhibits brittle fracture at a relatively low stress of 88MPa due to a TiC interphase at all NiTi powder boundaries. The volume fraction, orientation, shape, and spatial distribution of the microchannels is fully controlled with this method. This makes the structure attractive for biomedical applications, specifically bone implants. The potential shape memory properties achievable through optimized processing would also make the structure effective for energy absorption or actuators.

高炭素鋼線の極低温・均一変形伸線のための潤滑剤の検討

Recently, interest in global environment has been increasing. Demands for improved structural components and lightweight parts are increasing. It is further necessary to increase the strength of high-carbon steel wires. Delamination is a critical problem of high-strength steel wire. A major factor in the delamination is strain aging by the heat generated during wire drawing. Therefore, cryogenic drawing is effective for avoiding strain aging. In this study, the heat generated during wire drawing is focused on, and the drawing force in cryogenic drawing with various types of lubricants, i.e., liquid or powder lubricants, is discussed. Cryogenic drawing was realized by holding the wire in a box filled with liquid nitrogen prior to drawing, and the drawing force was measured using a load cell. An appropriate lubricant in cryogenic drawing was found to be powder lubricant.

The Effects of Non-Metallic Inclusion on Ductile Damage of High Carbon Steel Wire in Multi-Pass Dry Drawing Process

The objective of this study is to evaluate how the inclusion sizes influence the damage value and the maximum hydrostatic stress during multi-pass dry drawing process. It was well known that non-metallic inclusions can lead to material fracture during metal forming process, and be harmful to the quality of the final product. In multi-pass dry wire drawing, the temperature rise during deformation greatly decreases the quality of final product. In this study, the pass schedule in which initial diameter of 3.55 mm is reduced to final diameter of 2.115 mm was isothermally designed for the high carbon content steel. Spherical non-metallic inclusion of Al2O3 is located in the center of a steel rod. Influences of inclusion size, 5 μm, 10 μm, 20 μm and 50 μm in initial diameter 3.55 mm on ductile damage was investigated by FE-simulation in which material fracture was estimated using normalized Cockcroft and Latham criterion.

The Analysis of the Mechanical Properties of High Carbon Steel Wires after Multipass High Speed Drawning Process in Conventional and Hydrodynamic Dies

Abstract In this work the influence of the drawing speed on lubrication conditions and mechanical properties of high carbon steel wires drawn in conventional and hydrodynamic dies has been assessed. The drawing process of ϕ5.5 mm wires to the final wire of ϕ1.7 mm was conducted in 12 passes, in industrial conditions, by means of a modern Koch multi-die drawing machine. The drawing speeds in the last passes were: 5, 10, 15, 20 and 25 m/s. For final wires ϕ1.7 mm the investigation of mechanical properties has been carried out, in which yield strength, tensile strength, uniform and total elongation and also number of twists were determined. It has been shown that the increase of drawing speed from 5 m/s up to 25 m/s caused the increase by 6% strength properties and decrease of plasticity properties by 10%. Higher values of tensile strength and yield strength of the wires drawn conventionally with high speeds are associated with worse conditions, while in case of wires drawn hydrodynamically the main factor which caused the increase of strength properties was high lubricant pressure in hydrodynamic die, which caused the increase of total draft.