Hard-drawn Wires Research Articles

Application of external prestressing on the rehabilitation of reinforced concrete beams

Concrete structure experiencing any form of distress due to multiple reasons; need remedial, strengthening, and rehabilitation measures, if the structure is to attain serviceability and strength requirements of different elements. Further, the external welding reinforcement and prestressing of the reinforced concrete members have been proven to provide an effective strengthening approach. The prestressed concrete describes a type of concrete where internal stresses are instituted to counteract the multiple tensile stresses that are characteristics of service loading. In these concrete structures, cables, hard-drawn wires or bars of high strength alloy steel are employed as tendons to generate the counteracting stresses. The prestressed concrete is made up of an active combination of steel and concrete as these materials are traditionally stressed before the application of external loads. The prestressing technique has been comprehensively reviewed in numerous articles showing that it is more effective than the RCC structures. External prestressing is emerging as an essential component of prestressing as it is structurally attractive and economical. In external prestressing, the tendons are placed outside the member to improve the load-bearing capacity of the structures and their members. In this study, a beam exposed to various loading condition and distress is strengthened using external prestressing. The ultimate deflection and failure characteristics were evaluated using different loading scenarios; beam weight, live weight, and dead weight. The results for the prestressing analysis was provided for 10 and 20 strands.

高Si硬引線の回転曲げ疲労強度に及ぼすショットピーニングの有無と微小ストレート切欠きの影響

In late years a study of advantageous high Si hard-drawn wire is pushed forward in comparison with oil tempered wires on a cost side. In this study, influence of the minute notch which gave it to rotary bending fatigue strength of the high Si hard-drawn wire and influence of the shot peening were investigated. The test bar which we gave shot peening treatment and notch to was prepared, and each hardness, residual stress, fatigue strength were investigated. A Nakamura-type rotary bending fatigue testing machine was used in fatigue test. SEM was used for fracture surface and organization evaluation. The fatigue limit of shot peening materials rose 45% in comparison with untreated material. When the linear notch of the 30 degrees〜90 degrees notch angle was given, in the case of notch angles less than 60 degrees, the fatigue limit of untreated material and the electrolytic grinding material became equal to smooth specimen. Influence of the wire drawing structure is considered as a reason.

353 高Si硬引線の疲労強度に及ぼす微小欠陥の影響とショットピーニングによるその改善 : ストレート切欠きの場合(金属疲労)

353 高Si硬引線の疲労強度に及ぼす微小欠陥の影響とショットピーニングによるその改善 : ストレート切欠きの場合(金属疲労)

352 高Si硬引線の疲労強度に及ぼす微小欠陥の影響とショットピーニングによるその改善 : ビッカース圧痕、ロックウェル圧痕の場合(金属疲労)

352 高Si硬引線の疲労強度に及ぼす微小欠陥の影響とショットピーニングによるその改善 : ビッカース圧痕、ロックウェル圧痕の場合(金属疲労)

Diameter dependence of the giant magnetoimpedance in hard-drawn CoFeSiB amorphous wires

The as cast CoFeSiB amorphous wire with 135 μm was drawn out to wires with diameters of 84, 64, and 40 μm, respectively. The magnetoimpedance of the hard-drawn wires were investigated in comparison with the as cast one. For the hard-drawn wire of diameter 64 μm, the magnetoimpedance ratio ΔZ/Z0 can reach 269.9%. There is a transform of the domain structure from the inner core longitudinal to the circular in hard-drawn wires compared with the as cast one. The frequency dependence of the magnetoimpedance in longitudinal and transverse cases show that both circumferential and longitudinal axial anisotropies may depend on the radial distance from the axis of the wire.

Effect of elevated temperatures on mechanical properties of overhead conductors under steady state and short-circuit conditions

The loss of mechanical properties of conductors of transmission overhead lines is, from the point of view of their thermal stressing, the function of temperature and time of duration. Elevated temperatures generally result in the loss of the tensile strength of conductors which indirectly leads to increased sag and decreased safety heights or ground clearances, thus reducing the operational reliability of transmission lines. The paper presents results of a research into mechanical properties of hard-drawn wires and stranded homogeneous and combined conductors made of aluminum and aluminum-alloys at elevated temperatures under conditions of the steady-state operation. Further, results are shown of the changes of mechanical properties of such conductors as a result of short-circuit heating.

Effect of deformation and oxygen content on mechanical properties of different copper wires

Investigations were done at dip-forming, contirod and SCR copper wire rods. These continuously cast and hot rolled copper wire rods (8 mm in diameter) were cold drawn in two drawing programmes (soft and hard drawn) to various diameters without any intermediate annealing. The results of influence of deformation and oxygen content on the flow stress, tensile elongation and number of twist to failure are given. Strength and strain hardening rates of hard-drawn wires always were higher than the soft-drawn wires. Oxygen effect on the ductility of copper wires measured with the tensile elongation and the number of twist to failure is not clear at large drawing prestrains.

Increased Barkhausen noise of hard-drawn 50% nickel-iron at low temperatures

To resolve the question whether thermal fluctuation fields have an influence on the Barkhausen noise, its energy spectrum in the frequency range from 0.1 Hz to 80 kHz was measured at low temperatures. In particular, we investigated the noise of a hard-drawn wire of 50NiFe, the spectrum of which depended on the field rate d H/d t at low frequencies, because there was a weak coupling between subsequent Barkhausen pulses. We found that the noise at medium frequencies was much higher after the sample had been cooled to temperatures below 77 K. Several interpretations of the effect will be discussed, but the most probable appears to be that thermal fluctuation fields do indeed disturb the strong coupling which exists between neighbouring divisions of a Bloch wall at a sufficiently low temperature.

Variability in annealing rate of tough-pitch copper wire

The effects of changes in process variables during fabrication of hard-drawn wire on the wire annealing rate have been investigated. The rate of annealing is strongly dependent on the temperature of hot-rolling from wire bar slice to rod. Extreme conditions of the time and temperature of the rod anneal prior to drawing can have a considerable effect on the annealing rate, but are unlikely to contribute much to the variability of annealing rates in practice. The ingot size, delay before quenching after hot-rolling, and wire drawing conditions are of little importance. The reasons for the changes in annealing rates are discussed and a suggestion made for improving the wire fabrication procedure in the spiral elongation test.

New observations on the formation of unduloids on wires

The paper presents the results of an investigation of unduloid formation on hard-drawn and soft silver wires with diameters between 0.16 and 1.0mm. It has been established that unduloids only form on hard-drawn wires. Consequently, unless wire surface hardness is taken into account, the existing theories about the surface melting of current-overloaded wires may be incorrect. Furthermore, experiments are reported on hard-drawn and soft wires heated with a gas flame where a similar formation of unduloids only occurred on the hard-drawn wires. It has been found that, for both soft and hard-drawn wires, there is a close similarity between their behaviour when heated by either a gas flame or an electric current.

Characteristics of magnetostrictive wire spark chambers

A spark chamber which gives both coordinates of the spark with a single plane of wires has been studied. While gas fillings of helium and neon-helium have been found unsuitable, good results have been obtained with argon and helium-argon mixtures. The velocity of the pulses in the wires is measured for every pulse, using the pulse reflected at one end of the wires. It has been found that hard-drawn wires give signals of better shape and of amplitude less variable with the tension of the wire, than the half-annealed wires.

Soldering hard-drawn wires to terminals

Soldering hard-drawn wires to terminals

Propagation of Large Barkhausen Discontinuities. II

Large Barkhausen discontinuities have previously been observed by Forrer and by Preisach in nickel wires and hard-drawn wires of the nickel-iron series respectively under stress. A prediction that these discontinuities occur in form of a propagation along the wire, starting at a nucleus, has now been substantiated. In the experiments an additional local field was used to start the propagation at a definite point on the wire, which was in a uniform magnetic field, and the velocity was determined by measuring the short time interval elapsing between the passage through two search coils around the wire. With a fixed value of tension on the wire, the velocity $v$ was found to vary approximately linearly with the applied uniform field $H$, so that $v=A(H\ensuremath{-}{H}_{0})$. $A$ is the slope of the velocity-field characteristic and ${H}_{0}$ is called the critical field. Measured velocities range from 500 to 40,000 cm ${\mathrm{sec}}^{\ensuremath{-}1}$. ${H}_{0}$ varies with composition, amount of cold working, and with the stress applied to the wire. Increasing tension reduces the critical field over the greater part of the Ni-Fe alloy composition range. The behavior of ${H}_{0}$ with increasing and decreasing tension shows the presence of elastic hysteresis. $A$ is nearly constant for changes in tension, in diameter of wire, for composition of wire, and is the same for a strip. Its value is approximately 25,000 cm ${\mathrm{sec}}^{\ensuremath{-}1}$ ${\mathrm{gauss}}^{\ensuremath{-}1}$.The existence of eddy currents limits the speed with which magnetism can penetrate the wire. A rough calculation of this time gives values in the neighborhood of ${10}^{\ensuremath{-}2}$ sec. Thus a discontinuity travelling at ${10}^{4}$ cm per sec. occupies a length of some 100 cm on the wire. This was substantiated both by measurements of the peak voltage induced in a search coil and by oscillograms taken of the induced voltage. The observed passage times agree well with the theoretical penetration times.The constancy of the $v\ensuremath{-}H$ slope for wires of different diameters is believed toindicate that the velocity depends upon surface phenomena rather than volume phenomena. The velocity would thus be determined by conditions existing near the front edge of the discontinuity where the penetration is still slight. The critical field is believed to represent a threshold value of magnetic field which must be exceeded at all points of the wire before reversal of magnetism can occur. The excess of the impressed field over the critical is nullified during propagation by the fields arising from the eddy currents. A possible picture of the discontinuity is one in which the reversal occurs within a minute distance of an approximately conical surface in the wire, the edge of the base of the cone forming the front of the wave.The explanation advanced by Preisach for the asymmetric hysteresis loops found if one limit of the magnetization cycle was reduced has been extended. In this case magnetic inhomogeneities act as nuclei. Mechanical distortion introduces inhomogeneities of another type which also lead to the very easy formation of a nucleus. The phenomena found with torsion are more complicated than for tension. In some cases the slope of the $v\ensuremath{-}H$ lines shows appreciable variation with direction of twist. The results of tests with various compositions of the nickel-iron series are described using both tension and torsion, but no newrelations to other properties of these alloys can be given so far. Identifying ${H}_{0}$ with coercive field, R. Becker's theory has been compared with our results. It appears that in most cases increased elastic tension and increased cold working stresses shift ${H}_{0}$ in opposite directions.

Propagation of Large Barkhausen Discontinuities

Large Barkhausen discontinuities have previously been observed by Forrer and by Preisach in nickel wires and hard-drawn wires of the nickel-iron series respectively under stress. A prediction that these discontinuities occur in form of a propagation along the wire, starting at a nucleus, has now been substantiated. In the experiments an additional local field was used to start the propagation at a definite point on the wire, which was in a uniform magnetic field, and the velocity was determined by measuring the short time interval elapsing between the passage through two search coils around the wire. With a fixed value of tension on the wire, the velocity $v$ was found to vary approximately linearly with the applied uniform field $H$, so that $v=A(H\ensuremath{-}{H}_{0})$. $A$ is the slope of the velocity-field characteristic and ${H}_{0}$ is called the critical field. Measured velocities range from 500 to 40,000 cm ${\mathrm{sec}}^{\ensuremath{-}1}$. ${H}_{0}$ varies with composition, amount of cold working, and with the stress applied to the wire. Increasing tension reduces the critical field over the greater part of the Ni-Fe alloy composition range. The behavior of ${H}_{0}$ with increasing and decreasing tension shows the presence of elastic hysteresis. $A$ is nearly constant for changes in tension, in diameter of wire, for composition of wire, and is the same for a strip. Its value is approximately 25,000 cm ${\mathrm{sec}}^{\ensuremath{-}1}$ ${\mathrm{gauss}}^{\ensuremath{-}1}$.The existence of eddy currents limits the speed with which magnetism can penetrate the wire. A rough calculation of this time gives values in the neighborhood of ${10}^{\ensuremath{-}2}$ sec. Thus a discontinuity travelling at ${10}^{4}$ cm per sec. occupies a length of some 100 cm on the wire. This was substantiated both by measurements of the peak voltage induced in a search coil and by oscillograms taken of the induced voltage. The observed passage times agree well with the theoretical penetration times.The constancy of the $v\ensuremath{-}H$ slope for wires of different diameters is believed toindicate that the velocity depends upon surface phenomena rather than volume phenomena. The velocity would thus be determined by conditions existing near the front edge of the discontinuity where the penetration is still slight. The critical field is believed to represent a threshold value of magnetic field which must be exceeded at all points of the wire before reversal of magnetism can occur. The excess of the impressed field over the critical is nullified during propagation by the fields arising from the eddy currents. A possible picture of the discontinuity is one in which the reversal occurs within a minute distance of an approximately conical surface in the wire, the edge of the base of the cone forming the front of the wave.The explanation advanced by Preisach for the asymmetric hysteresis loops found if one limit of the magnetization cycle was reduced has been extended. In this case magnetic inhomogeneities act as nuclei. Mechanical distortion introduces inhomogeneities of another type which also lead to the very easy formation of a nucleus. The phenomena found with torsion are more complicated than for tension. In some cases the slope of the $v\ensuremath{-}H$ lines shows appreciable variation with direction of twist. The results of tests with various compositions of the nickel-iron series are described using both tension and torsion, but no newrelations to other properties of these alloys can be given so far. Identifying ${H}_{0}$ with coercive field, R. Becker's theory has been compared with our results. It appears that in most cases increased elastic tension and increased cold working stresses shift ${H}_{0}$ in opposite directions.

XXXVI. On the effect of permanent elongation on the cross section of hard-drawn wires

(1890). XXXVI. On the effect of permanent elongation on the cross section of hard-drawn wires. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science: Vol. 29, No. 179, pp. 355-358.

XX.—On the Variation with Temperature of the Electrical Resistance of Wires of certain Alloys

The alloys which we used in the following experiments were in the form of very thin hard-drawn wires,—the same as those whose thermo-electric properties we described in a paper published in the Transactions of this Society in 1877. They were prepared by Messrs. Johnson and Matthey of Hatton Garden, London. In giving their constitution we rely upon the authority of the manufacturers, as the quantities we had were too small to admit of our having them analysed.