Tire Cord Research Articles

Study on Control of Inclusion Compositions in Tire Cord Steel by Low Basicity Top Slag

AbstractTop slag melting experiment was conducted in a silicon molybdenum furnace with tire cord steel billet. The influence of top slag composition on the plasticity of CaO–Al2O3–SiO2–MgO inclusion and inclusion plasticization conditions was calculated by thermodynamic software FactSage. Use the thermodynamic calculation to guide the laboratory experiments to study slag compositions influence inclusions composition. Then industrial experiments were conducted based on the theoretical calculation and results of laboratory experiments. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were used to determine the morphology and composition of inclusions in steel. All studies show that in the CaO–Al2O3–SiO2–10% MgO diagram, when CaO = 8–48%, SiO2 = 35–75%, Al2O3 = 0–32%, inclusions are in the plastic area. When basicity of top slag is certain, Al2O3 content in inclusions increases with the increase of Al2O3 content in the slag, and the distribution of inclusions becomes scattered with the increase of Al2O3 content in slag. Inclusion plasticization can be achieved when the binary basicities of top slag are 0.6, 0.8–1.2, 1.4 and corresponding w(Al2O3)s are 2–15%, 2–10%, <2%. According to industrial experimental results, when top slag basicity decreases from 1.5 to 0.67–0.9 and Al2O3 content decreases below 10 wt%, the inclusion falls into plastic area. It is feasible in practice to control the CaO–Al2O3–SiO2–MgO inclusions plastic through adjusting Al2O3 content in slag.

폴리케톤 섬유/EPDM 고무의 접착특성에 미치는 폴리도파민 처리의 영향

Polyketone fiber can be used for reinforcing mechanical rubber goods (MRG) such as hoses, tire cords, protective gloves, and ropes. However, the reactivity of the surface of polyketone fibers decreases with a high crystallization of the polyketone fiber. Hence, modification of the surface of polyketone fiber is essential for improving the surface functionality and the fiber-matrix interfacial adhesion. In this study, dopamine treatment has been employed for modifying the polyketone fiber surface in order to improve the adhesion between polyketone fiber and ethylene propylene diene monomer (EPDM) rubber. Chemical composition of the modified fiber surface was examined using energy dispersive spectroscopy (EDS), attenuated total reflectance-infrared spectroscopy ((ATR)-IR), and X-ray photoelectron spectroscopy (XPS). Adhesion properties with the rubber were examined by an H-adhesion test. Surface energy and surface morphology were evaluated using contact angle and scanning electron microscopic (SEM) measurements, respectively. A polydopamine layer was formed on the polyketone fiber surface after dopamine treatment, thereby changing the surface energy via the oxidation polymerization of dopamine.

Formation Mechanism of CaO-SiO2-Al2O3-(MgO) Inclusions in Si-Mn-Killed Steel with Limited Aluminum Content During the Low Basicity Slag Refining

Pilot trails were carried out to study the formation mechanism of CaO-SiO2-Al2O3-(MgO) inclusions in tire cord steel. 48 samples were taken from 8 heats of liquid steel during secondary refining, which were subsequently examined by an automatic scanning electron microscope with energy dispersive spectrometer (SEM–EDS). Characteristics of thousands of oxide inclusions at different refining stages were obtained, including their compositions, sizes, morphologies, etc. Based on the obtained information of inclusions, details during formation of CaO-SiO2-Al2O3-(MgO) inclusions were revealed and a new mechanism was proposed, including their origin, formation, and evolution during the refining process. It was found that CaO-SiO2-Al2O3-(MgO) inclusions were initially originated from the CaO-SiO2-MnO-(MgO) inclusions, which were formed during BOF tapping by the coalescence between MnO-SiO2 deoxidation products and the emulsified slag particles because of violent flow of steel. This can be well confirmed by the evaluation of the formation thermodynamics of CaO-SiO2-MnO-(MgO) inclusions, which was proved very difficult to be produced by intrinsic reactions inside liquid steel. Because of chemical reactions between CaO-SiO2-MnO-(MgO) inclusions and molten steel, they were mainly changed into CaO-SiO2-MnO-Al2O3-(MgO) and partially into CaO-SiO2-Al2O3-(MgO), which may be detrimental to the cold drawing ability of coils. Based on this finding, improvements were made in industrial production during BOF tapping and secondary refining. The results indicated that such (CaO-SiO2)-based inclusions existed in conventional process were effectively decreased after the improvements.

Voltammetric behavior of I2/2I− redox system on boron-doped diamond electrode in various media and its utilization for the indirect detection of tin(II)

Abstract Simple and fast electroanalytical method for the detection of tin(II) in bronze has been developed. It is based on synergistic combination of boron-doped diamond electrode as sensitive voltammetric sensor and reaction electrochemistry. The voltammetric response is enhanced by chemical recycling of iodide after electrogeneration of iodine followed by reaction with Sn(II). The charge transfer for the oxidation of iodide to iodine on boron-doped diamond electrode was investigated and characterized in eight different electrolytes. Charge transfer coefficient (0.58 in 0.1 mol L − 1 H 3 PO 4 –0.35 in 0.1 mol L − 1 HCl), formal potential (0.65 V in 0.1 mol L − 1 HClO 4 –0.90 V in 0.1 mol L − 1 NaHCO 3 ) and standard heterogeneous rate constant (4.6 × 10 − 3 cm s − 1 for H 3 PO 4 –2.2 × 10 − 3 cm s − 1 for NaHCO 3 ) were estimated. Based on these values it was observed that the charge transfer is irreversible, but the response is suitable for the quantification of tin(II) in bronze for tire cords. The detection limit of 2.3 × 10 − 7 mol L − 1 was achieved by linear sweep voltammetry. This value is comparable with some expensive and time consuming techniques routinely used for this type of determination.

POSSIBILITIES TO USE TEXTILE CORD WASTE FROM USED TIRES FOR CONCRETE

The goal of the study was to determine the effect of waste tire cord yarn with attached rubber particles on the properties of concrete made of different types of cement (Portland cement without additives – CEM I, Portland cement with limestone additive – CEM II). The filament waste (added at 0%, 2%, 4%, 6%, 8%, and 10% of the amount of fine aggregate) is water absorbing textile fibre additive with rubber particles, therefore a bigger amount of water is required to prepare the concrete mixture. With waste additive, the density and compressive strength of concrete reduces, but water absorption increases. The forecasted freeze-thaw resistance of concrete with cement type CEM I and recycled tire cord increases and slightly reduces when cement type CEM II is used, however retains similar resistance in about 1000 freeze-thaw cycles. The coefficient of thermal conductivity decreases approx. 35%, when 10% of recycled tire textile cord is added to concrete mixture.

Influence of tire cord layers and arrangement direction on mechanical properties and vibration isolation of chloroprene rubber composite materials reinforced with polyester tire cord

Abstract Polyester tire cord is often used as reinforcement in the production of chloroprene rubber (CR) composite materials. This study investigated the influences of polyester tire cord layers and arrangement directions on the mechanical properties and vibration isolation of CR composite materials. The experimental results indicate that the optimal molding condition for bonding tire cord with CR composites is 170°C for 30 min, which enables tire cord-reinforced CR composites to exhibit maximum pull-out strength. The compression set, tensile strength, and tear strength of CR composites increased with the increasing number of tire cord layers, and the stretching direction parallel to the arrangement direction of the tire cord produced optimal reinforcement effect. Moreover, the storage modulus of CR composites is better than that of pure CR at low temperature, although it reduced the tan delta at glass transition temperature. Regarding the vibration isolation properties, the transmissibility ratio decreased at resonance frequency, while the damping ratio increased when the CR is reinforced with increasing number of tire cord layers.

Effect of V and N on Microstructures and Properties of Grade-70 Tire Cord Steel during Cold Drawing

Commercial grade-70 tire cord steel was microalloyed with V and N to explore the possibility of substituting V for C and the effect of V and N on cementite dissolution during cold drawing process. Tensile strength, elongation and torsion laps of cold-drawn wires were determined. Microstructures of secondary phases were studied by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). Saturation magnetization was measured by using a vibrating sample magnetometer (VSM) to evaluate cementite dissolution during cold drawing process. Experimental results showed that with the increase of V content, tensile strength increased, elongation slightly decreased, and the torsion laps of the cold-drawn wires decreased. Results also showed that with the increase of N content, a peak (increasing first and then decreasing) appeared in the tensile strength graph, and an increase of elongation and a decrease of torsion laps of the cold-drawn wires occured. N is soluble in ferrite when its content is low. The increase in the content of N to 82 × 10−6 will result in the precipitation of the V-containing secondary phases. Also, cementite tended to be stable during cold drawing process with the increase of V and N contents. Grade-80 tire cord steel can be replaced by grade-70 tire cord steel microalloyed with 0.086 mass% V.

Structural Evolution of Pearlite in Steels with Different Carbon Content under Drastic Deformation during Cold Drawing

Steel wires, under severe cold drawing deformation, develop high strength. High carbon steel (C>0.80%) has a great demand in the steel market because of the extremely high strength (5-6GPa). For this reason it is relevant to increase the knowledge on the structural evolution and deformation mechanisms involved during wiredrawing process due to their critical applications, among which we can mention wires for: bridges, cranes and tire cord. The mechanical behaviour aptitude is determined by torsion test. When the fracture surface is flat, the wire is apt. On the opposite, an irregular fracture surface (delamination) means poor mechanical properties.This paper presents a comparative study on steel wires with different carbon contents (0.40% C and 0.80% C) in order to compare the structural evolution at high deformation and to verify the impact of carbon content on the pearlite deformation and cementite stability. Samples tested under torsion with and without delamination problems, were selected. The microstructural study was carried out applying light and scanning electron microscopy (SEM). Finally, the structural information was correlated with results of differential scanning calorimetry (DSC) and thermodynamic properties obtained by Fact Sage simulation.The structural study verified the presence of curling phenomenon in both steels grades, with different carbon content. The effect of the ferrite on deformation mechanisms during wiredrawing was clearly visualized. It was possible to verify differences (∼ 26%) in the interlaminar spacing (λ) of the pearlite between wires that present normal and delaminated behaviour under torsion test. The ductility loss (in the delaminated wire) is promoted by multiple causes: higher interlaminar spacing, high nitrogen content in the product and the presence of dynamic strain aging, which is promoted by cementite destabilization and the formation of ɛ carbide.

Investigation of precipitation and growth behavior of Ti inclusions in tire cord steel

The precipitation and growth behavior of Ti inclusions in 82 grade tire cord steel was investigated by thermodynamic and kinetic calculation. Under the same condition without considering microsegregation, the priority of inclusions to precipitate is in the order of Ti3O5, Ti2O3, and TiO2. The formation of TiN cannot precipitate in the liquid region, or in two-phase phase region. Considering microsegregation, the formation of TiN only took place in the two-phase region where the solid fraction is greater than 0.95, or in solid phase region. The segregation degree of oxygen is the strongest, followed by titanium and last by nitrogen. The higher the solute concentration, the earlier the inclusions precipitate. The greater the cooling rate during solidification, the shorter the time for Ti inclusion particles growth and the smaller the size of precipitated Ti inclusion particles. Under the current control condition, in the refining process, the main types of Ti inclusions are Ti3O5, which usually coexists with other oxides. In the billets, the main types of Ti inclusions are TiN in the tire cord steel. The calculated size of precipitated Ti oxide is in close agreement with the one measured by SEM.

Photocatalytic degradation of Tire Cord manufacturing wastewater using an immobilized nanoTiO2 photocatalytic reactor

In this study, an immobilized nanoTiO2 photocatalyst was developed for the degradation of Tire Cord manufacturing wastewater with low BOD5/COD ratio (0.1–0.2). The interactive effects of three numerical independent factors (initial COD concentration, initial pH, and reaction time) on the process performance were studied. The process performance was evaluated by monitoring three process responses including COD removal efficiency, specific COD removal rate and BOD5/COD ratio after treatment. The process was modeled and analyzed using response surface methodology. Maximum COD removal efficiency and BOD5/COD ratio were modeled to be 38% and 0.5, respectively, at CODin of 350 mg/l and initial pH of 11. The photocatalytic process induced by O3 and O3/H2O2 showed a remarkable improvement in the process responses studied. Photocatalytic process with sequence regeneration with ozonation could achieve higher COD removal efficiency and BOD5/COD ratio relative to that obtained from regeneration by aeration.

Research on Transformation Mechanism of Oxide Inclusion in Tire Cord Steel

In order to investigate the relation and transformation mechanism of two type oxide inclusions (MnO–Al2O3–SiO2 and CaO–Al2O3–SiO2 system) in tire cord steel the experiment was carried out. It’s found that oxide inclusions’ transformation has experienced MnO–Al2O3–SiO2 type at RH stage, CaO–Al2O3–SiO2 type at LF stage and soft blow argon stage, and finally MnO–Al2O3–SiO2 type in casting blank and billet during the production process of test steel. According to the analysis of reaction among slag/steel/inclusion it’s found that Ca content in steel is a major factor for transformation of inclusion composition. With the rising of Ca content in liquid steel the formation of CaO becomes easier and it is good for the formation of CaO–Al2O3–SiO2 complex inclusion. When the [O] content in steel is less than 0.002 %, the Al2O3–CaO–2SiO2 inclusions may be generated if Ca content in steel is more than 0.0001 %.

Genetic Analysis for Large TiN Inclusions in Wire Rod for Tire Cord Steel of SWRH82A

The law of element segregation of Ti, N, Mn and S, and the sequence of selective precipitation of TiN and MnS inclusions during solidification of molten steel of SWRH82A are studied on the basis of thermodynamics. The origin of large TiN inclusions which affect the titanium inclusions point penalty in SWRH82A wire rod is analyzed based on the research on the distribution characteristics of MnS and large size of TiN inclusions observed on metallographic specimen of SWRH82A steel wire rod. The solidification segregation ratio of Ti is far more than that of N, and the solidification segregation ratio of S is far more than that of Mn. In the range of cooling rate of the continuous casting production, the cooling rate of solidification has little effect on the segregation ratios of Ti, N, Mn and S. MnS inclusions will precipitate earlier than TiN inclusions during solidification of the molten steel of SWRH82A. The large TiN inclusion which is wrapped by MnS in the SWRH82A wire rod may be foreign inclusions and it is not precipitated product during solidification in the molten steel of SWRH82A.

Influence of tire-cord layers and arrangement direction on the physical properties of polyester tire cord reinforced with chloroprene rubber composite materials

AbstractPolyester tire cord is used as reinforcement for making chloroprene rubber (CR) composite materials. This study investigated the influences of polyester tire-cord layers and arrangement direction on the mechanical properties of CR composite materials. The experimental results indicate that the optimal temperature and heating time for CR vulcanization are 170°C and 35 min, respectively. This processing condition enabled CR to achieve rapid vulcanization and exhibit optimal mechanical properties. The hardness and compression stiffness of the CR composites increased with increasing tire-cord layers. This phenomenon reduced the occurrence of creep under long-term loading but increased the compression set. In addition, when the arrangement direction of the tire cord and the stretching direction of CR were perpendicular, crack formation and growth easily developed, which reduced the bending-fatigue resistance of CR.

Inclusion composition control in tyre cord steel by top slag refining

In order to improve the inclusion type and composition in tyre cord steel, ladle furnace refining has been simulated by laboratory experiments and thermodynamic calculation. It was found that slag metal reaction time and top slag composition have an important influence on the inclusion compositions in the final steel. To produce the desired low melting point ductile inclusions the optimum conditions were: reaction time 60 min, basicity (CaO/SiO2) of top slag in the range of 1·0–1·2 and Al2O3 content of slag in the range of 3–9 mass-%. These were then confirmed in industrial trials.

タイヤコードの誕生から将来に向けた取り組み

タイヤコードの誕生から将来に向けた取り組み

<i>In Situ</i> Observation of Inclusions Behavior in Molten State and Solidifying Interface of Tire Cord Steel

In this study, a confocal scanning laser microscopy was used to in situ observe the collision and aggregation behavior of inclusions in molten state and the pushing/engulfing behavior in the solidifying interface of tire cord steel. The results show that the inclusion particles will be captured into the grains in the solidification front for the inclusions with a diameter are larger than 53.4μm at a cooling rate of 1 K/s. Moreover, the attraction force of inclusion particles in molten state is in the order of 10-16N~10-14 N in tire cord steel.

The [Ti] Content Control of the Tire Cord Steel 82A

Based on the characteristics of the production process and quality level of the cord steel 82A, this paper focus on the analysis of the converter terminal temperature, terminal oxidability and the converter slag on the influence of the content of titanium in steel, which combined the oxidation removing related theory of titanium element in steel, and puts forward effective measures of ultralow titanium content controlling in steel, and obvious effects have been obtained in the production: the average [Ti] content is 4.9ppm in the end products, in which the proportion of less than 5ppm is above 90%.

Biobased composites

Biobased thermoplastics, such as poly(lactic acid), have attracted much attention in recent years as an alternative to oil-based plastics both in academia and industry. Based on renewable raw materials these polymers offer advantages in terms of decreased dependence on fossil resources and reduced CO2 footprint in accord with sustainability ideas and climate protection. In order to improve the properties of these materials, reinforcement with biobased fibers represents a promising option. An alternative route to glass and natural fiber reinforcement was taken and intensively investigated. The novel approach is based on the use of cellulose man-made fibers, in particular rayon tire cord yarn, as a biogenic reinforcing component. It was demonstrated that short fiber rayon reinforcement leads to dramatic improvements in the mechanical properties of various biobased and partially biobased matrix materials. While stiffness is easily enhanced also with natural fibers, the use of rayon results in considerable improvements in strength and impact properties in contrast to natural fiber reinforcement. For example, an enhancement of more than 500 % was observed in notched Charpy impact strength of poly(lactic acid). In the present contribution results concerning composite mechanical properties will be presented for various biobased matrix materials with special emphasis on the role of the fiber-matrix interphase. By reactive extrusion this interphase can be tailored from being weak (anti-coupling), intermediate (no modification) or strong (covalent coupling). Implications for the composite properties as a function of matrix stiffness will be discussed. Other factors influencing the composite properties such as fiber length and fiber diameter will be considered as well. Finally, some general conclusions will be drawn concerning future work and industrial prospects.

Study on Inclusions in Wire Rod of Tire Cord Steel by Means of Electrolysis of Wire Rod

AbstractThe wire rod electrolysis is an extraction approach of inclusions in wire rod based on non‐aqueous solution electrolysis, which can extract large‐size inclusions (>20 µm) from Φ5.5 mm wire rod even about Φ0.22 mm cord wire. Analysis and study on large‐size inclusions in tire cord steel from domestic and overseas steel plants were carried out by wire rod electrolysis, the study shows that the sizes of inclusions in wire rod of tire cord steel are far larger than those observed by metallographic microscope or scanning electron microscopy. Eighty percent large‐size inclusions in wire rod come from the involvement of reaction products of mold fluxes or refractories. Further study according to electrolysis of wire rod and cord wire presents that reaction products containing K and Na of mold fluxes and refractories are brittle and easy to break into more small inclusions. Wire broken during drawing process is mainly caused by large‐size and high‐hardness Al2O3 inclusions, inclusions containing high content MgO from reaction products of mold fluxes and refractories, and Ti(CN) inclusions.

Effect of Carbon Content on Ti Inclusion Precipitated in Tire Cord Steel

The precipitation of TiN inclusion during solidification of different carbon content of 0.72%, 0.82% and 0.95% in tire cord steel is thermodynamically studied respectively. The results show that the carbon content has obvious effect on TiN inclusion precipitated in tire cord steel of different strength levels. With the carbon content of tire cord steel increasing, the temperature before solidifying reduced gradually and the required activity product of titanium and nitrogen for TiN inclusion precipitation also declined gradually. With the same condition of initial Ti and N content in liquid steel, the size of TiN inclusion precipitated in tire cord steel of higher carbon content is bigger than that of lower carbon content. In order to control the harmful effects on processability of TiN inclusion precipitated in hypereutectoid tire cord steel of the ultra high strength level, the measures of smelting process must be taken to further reduce the titanium and nitrogen content in liquid steel.