Rolled Tape Research Articles

Mathematical Modeling in View of Property Prediction of DD11 Steel Laminated in LBC Liberty Galati

The paper presents a mathematical model for predicting the mechanical properties of hot rolled strips. The realization of this mathematical model relied on statistical measurements of the mechanical properties (Rm, Rp0,2 and A5) for the laminated strip in the LBC rolling mill from the Liberty Steel Galati steel plant. To achieve this mathematical model, there has been used the active experiment method.By means of this mathematical model, significant time and material savings can be made in the process of testing the mechanical properties for hot rolled tape.

Novel filler materials for composite out-of-plane joints

In the manufacture of the out-of-plane joints of composite stiffened panels, such as the connection between skin and T, I, omega shaped stiffeners, a filler material is needed to fill the void between the flanges, web and skin. The most common filler is a rolled unidirectional prepreg tape (“noodle”), which is not only expensive to manufacture, but also has low strength that can lead to premature failure of the loaded joint. In this work, eight novel filler concepts are introduced and experimentally validated against the baseline noodle via T-joint tensile tests. Polyamide nonwoven interleaved joints increase the damage tolerance of the structure and nonwoven nanofibres increase the failure initiation load. 3D printed fillers have lower strength but demonstrate the possibility of thermoplastic-thermoset hybrid structures. Fillers made of chopped prepreg match the strength of the baseline noodle and can serve as a low cost replacement. Another low cost, resin infused braided concept has lower strength, but its counterpart using multiple individual braids has the same strength as the unidirectional noodle. Moreover, the latter concept shows that different resin systems can be cured together without causing a knockdown in strength, and can serve as a basis for a range of novel applications.

Effects of Rolling Passes on the Transport Properties of 37-Filamentary AgAu-Sheathed Bi-2223 Tapes

Thirty-seven-filamentary AgAu-sheathed Bi-2223 tapes were fabricated by a powder-in-tube (PIT) process. And, the round wires (ϕ 1.86 mm) were rolled to 0.35-mm tapes with 12, 7, 5, and 4 rolling passes through flat rolling, respectively. The influences of different rolling passes on the core density, deformation, and transport properties of Bi-2223/AgAu tapes were systematically investigated. It was noticed that after rolling, the Vickers microhardness of the superconducting core and deform homogeneity along both the horizontal and vertical directions on the cross section of seven-pass rolled tape were better than those on the tapes with other passes, which proved the larger core density and uniform deformation with the seven-pass rolling process. Meanwhile for the wires with 12 and 7 passes, the AgAu/superconducting core interfaces were much flatter. With the rolling passes decreasing from 12 to 4, the critical current density (Jc) first increased and then decreased. Due to the better homogeneity and flatter interfaces, Jc reached the maximum value of 17.3 kA/cm2 on the seven-pass sample. Meanwhile, the enhancement of current capacities in magnetic field applied parallel to the Bi-2223/AgAu tape surface could also be recognized as the evidence of improving intergrain connections due to the higher density in seven-pass rolled tapes.

Development and evolution of biaxial texture of rolled nickel tapes by ion beam bombardment for high Tc coated conductors

High quality YBa 2Cu 3O 7 − x films on metallic substrates with high critical current densities well over 10 6 A/cm 2 can be prepared by the rolling assisted biaxially textured substrates (RABiTS) method. Nickel or its alloys have been used as biaxially textured substrates formed through a specific rolling and high temperature annealing procedures. In this paper, we report a newly developed process for developing biaxial texture in rolled Ni tape by argon ion beam bombardment. It is named the ion-beam structure modification (ISM) process. In the ISM processed Ni foils, X-ray diffraction ω scans showed the full width-half maximum (FWHM) value of the (2 0 0) peak was 5.7°. And the electron back scattering diffraction (EBSP) analysis based on scanning electron microscopy showed good {1 0 0} 〈0 0 1〉 cubic orientation and the mean grain size was determined as about 25 μm. The texture evolution of rolled Ni foils during ISM process is reported also. For ISM process, local temperature elevation and distribution arises from the ion bombardment, coupled with anisotropic incident ion penetration and propagation as a result of channeling effects in the metal lattice, are expected to play the major roles in the development of grain reorientation in the Ni foil. Due to the simplicity and efficiency of the ISM process, the technique shows a great promise for application in the industrial scale production of long-lengths of superconductor tapes.

Fabrication and properties of powder-in-tube processed MgB2tapes and wires

MgB 2 tapes were fabricated with MgB 2 powder and several sheath materials such as Cu, Cu-Ni, Fe, carbon steel(Fe-C) and stainless steel. High-density MgB 2 cores were obtained for these sheath materials. J c of the as-cold rolled(non heat treated) tape significantly increased with increasing the cross sectional area reduction by the cold working. Hard sheath materials (Fe-C and stainless steel) are effective to enhance J c values. These results can be explained by the densification of MgB 2 core. Non heat treated MgB 2 /(stainless steel) and MgB 2 /(Fe-C) tapes showed extrapolated J c values of 300-450kA/cm 2 at 4.2K and zero field. MgB 2 tapes show anisotropy in J c with respect to field orientation. This anisotropy can be explained by the MgB 2 grain orientation. Heat treatment after the cold rolling is effective to enhance J c values. An order of magnitude higher J c values were obtained for Fe-C and stainless steel sheathed tapes by the heat treatment. J c values extrapolated to zero field of MgB 2 /(SUS 316) and MgB 2 /(Fe-C) tapes reached 1,000kA/cm 2 at 4.2K.

ＭｇＢ２新超伝導体の線材開発

We fabricated MgB2 tapes and wires by a powder-in-tube (PIT) method, using MgB2 powder and several sheath materials such as Cu, Cu-Ni, Ni, pure Fe, carbon steel (Fe-C), and stainless steel. Jc of the as-cold rolled (un-sintered) tape significantly increased with the increase of total cross-sectional area reduction by the cold working. Hard sheath materials such as Fe-C and stainless steel are effective to enhance the packing density of MgB2 core and, therefore, to increase Jc values. Non heat treated MgB2 tapes with Fe-C and stainless steel sheaths showed extrapolated Jc values of-3.0-4.5×109A/m2 at 4.2K and zero field. Heat treatment after the cold rolling is effective to enhance Jc values. An order of magnitude higher Jc values were obtained for Fe, Fe-C, and stainless steel sheathed tapes after the heat treatment. Extrapolated Jc values well above 1010A/m2 at 4.2K and a zero magnetic field were obtained for stainless steel and Fe-C sheathed MgB2 tapes. Jc values of PIT-processed MgB2 tapes are less sensitive to strain than those of PIT-processed Bi-based oxide tapes. It is reported that the addition of soft metal powder such as In or Sn to the MgB2 powder is effective to enhance Jc values. We made -10m-long tapes with Ni sheaths, and fabricated small solenoid coil with this tape without sintering. The Ic of the coil was about 80% of the Ic of the short tape, indicating that the homogeneity of Ic in the 10m tape is fairly good. The coil generated 1.3kGauss at 4.2K.

Orientation-controlled nucleation of crystal silicon grains in amorphous silicon on a rolled nickel tape substrate

Crystal silicon grains with grain sizes in excess of 10 μm and orientation control over all three directions were produced by depositing an amorphous silicon thin film on a cold-rolled and annealed nickel tape and annealing at 600 °C for 2 h. The needle-like morphology of the grains indicated that the crystallization was mediated by NiSi2. All grains had their [110] axis about 21° off the surface normal. Furthermore, nearly all of them had the same rotation about the [110] axis except for presence of twins and/or type A–B formations. Despite the use of the nickel substrate, the Ni concentration within the Si film was below the detection limit of energy-dispersive x-ray spectroscopy (1019 cm−3). This low-Ni contamination level is attributed to the presence of an oxide layer between the Ni substrate and the Si film.

Magneto-optical images of Ag/Bi-2223 tapes processed by flat rolling, "sandwich" rolling and pressing

Magneto-optical imaging (MOI) has been used for study Ag/Bi-2223 tapes processed using flat rolling, "sandwich" rolling, and pressing methods for the intermediate mechanical deformation in powder-in-tube process. The results show that not only the density of the microcracks but also their distribution affect J/sub c/. Rolled tapes have a higher density of microcracks than pressed tapes. Although the flat rolled tape and "sandwich" rolled tape have the same level density of microcracks at the same reduction, the cracks in the former are more in the transverse direction than in the latter. In all three cases, J/sub c/ reaches a maximum value at an optimal reduction rate.

Continuous growth of epitaxial CeO 2 buffer layers on rolled Ni tapes by electron beam evaporation

A reel-to-reel, electron beam evaporation system has been developed to continuously deposit epitaxial CeO 2 and other oxide buffer layers on meter long-lengths of rolled Ni tapes. The deposition system includes two interconnected electron beam evaporation chambers and a chamber in which as-rolled Ni tape is in situ annealed to develop biaxial texture. An integral reel-to-reel system with tension control enables motion of the tape with little or no plastic deformation. When depositing epitaxial oxides on Ni, the formation of unfavorably oriented NiO needs to be avoided. Oxide-free, {100}〈100〉-oriented Ni tapes are prepared by control of the partial pressure of H 2 during Ni annealing. In situ annealed rolled Ni tape over 70 cm long and 1 cm wide has been deposited with an epitaxial CeO 2 buffer layer. Critical current density as high as 700 000 A/cm 2 at 77 K in self-field has been achieved for YBa 2Cu 3O 7− x (YBCO) films deposited on short segments of these buffered substrates. X-ray in-plane φ-scans have been performed as a function of length to determine the crystallographic consistency of the epitaxial CeO 2 over length. Results of scanning electron microscopy (SEM) examinations of the CeO 2 buffer layer microstructure are presented.

Mechanism of deformation and “sandwich” rolling process in Ag-clad Bi-based composite tapes

Abstract The mechanism of deformation was studied by stress-strain state analysis in Ag-clad Bi-based superconducting composite tapes prepared by the powder-in-tube method. The sausaging morphology was investigated and compared in tapes produced by different deformation processes. A new deformation process called “sandwich” rolling was developed to prevent the formation of sausaging and cracks in the longitudinal direction. In this “sandwich” rolling, the tape is deformed between two steel sheets. The stress-strain state of the tape in “sandwich” rolling is the same as that of uniaxial pressed tape because the deformation of steel sheets is negligible in comparison to that of Ag-clad Bi-2223 tape. The stress-strain distribution of the superconducting oxide core can be controlled by the curvature and hardness of the steel sheets. The critical current density of the sandwich rolled tape is improved in comparison with the flat rolled tape.

Sniffing up Trouble: Adhesive Tape Remover Pads

To the Editor.— I would like to bring to the attention of the medical community and hospitals the abuse potential of adhesive tape remover. Adhesive tape remover is often supplied to hospitals in the form of individually foilwrapped impregnated pads. Among their many ingredients are either perchloroethylene or 1,1,1-trichloroethane. These are the same active ingredients found in typewriter correction fluid, 1 which has been reported to have a high abuse potential among solvent sniffers. It is associated with coma, cardiac arrhythmias, and death. 2 This problem was recently brought to my attention by a 36-year-old woman who began hemodialysis in January 1986. Shortly thereafter she made frequent and demanding requests for adhesive tape remover in order to clear her skin of the adhesive tape that is used to hold fistula needles in place. A family member reported to me that she was inserting rolled adhesive tape remover pads in her