Cold Rolling Method Research Articles

Microstructure and texture evolution of ultra-thin grain-oriented silicon steel sheet fabricated using strip casting and three-stage cold rolling method

A 0.1mm-thick grain-oriented silicon steel sheet was successfully produced using strip casting and three-stage cold rolling method. The microstructure, texture and inhibitor evolution during the processing was briefly analyzed. It was found that Goss texture was absent in the hot rolled sheet because of the lack of shear deformation. After normalizing, a large number of dispersed MnS precipitates with the size range of 15–90nm were produced. During first cold rolling, dense shear bands were generated in the deformed ferrite grains, resulting in the intense Goss texture after first intermediate annealing. The microstructure was further refined and homogenized during the subsequent cold rolling and annealing processes. After primary recrystallization annealing, a homogeneous microstructure consisting of fine and equiaxed grains was produced while the associated texture was characterized by a strong γ-fiber texture. Finally, a complete secondary recrystallization microstructure consisting of entirely large Goss grains was produced. The magnetic induction B8 and iron loss P10/400 was 1.79T and 6.9W/kg, respectively.

Structural Modification of AD-1 Aluminium Alloy by the Method of Cold Rolling with Shift

Structural Modification of AD-1 Aluminium Alloy by the Method of Cold Rolling with Shift

A novel ultra-low carbon grain oriented silicon steel produced by twin-roll strip casting

A novel ultra-low carbon grain oriented silicon steel was successfully produced by strip casting and two-stage cold rolling method. The microstructure, texture and precipitate evolution under different first cold rolling reduction were investigated. It was shown that the as-cast strip was mainly composed of equiaxed grains and characterized by very weak Goss texture ({110}<001>) and λ-fiber (<001>//ND). The coarse sulfides of size ~100nm were precipitated at grain boundaries during strip casting, while nitrides remained in solution in the as-cast strip and the fine AlN particles of size ~20–50nm, which were used as grain growth inhibitors, were formed in intermediate annealed sheet after first cold rolling. In addition, the suitable Goss nuclei for secondary recrystallization were also formed during intermediate annealing, which is totally different from the conventional process that the Goss nuclei originated in the subsurface layer of the hot rolled sheet. Furthermore, the number of AlN inhibitors and the intensity of desirable Goss texture increased with increasing first cold rolling reduction. After secondary recrystallization annealing, very large grains of size ~10–40mm were formed and the final magnetic induction, B8, was as high as 1.9T.

Low-Cost Grain Oriented Silicon Steels Manufactured by Continuous Annealing

Low-cost grain oriented silicon steel produced by continuous annealing, low slab-heating temperature, and omitting normalization annealing is explored and analyzed. This type of grain oriented steel is designed to replace the non-oriented steels used for the production of transformers of medium and small sizes as specified in all GO steel producers catalogs. Fully secondarily recrystallized structure with magnetic properties of P1.7 = 2.04 W kg−1 and B8 = 1.76 T is obtained at temperature of 1050 °C within 10 min in the condition of two-stage cold rolling, whereas one-stage cold rolling method fails to initiate abnormal grain growth in the same processing parameters. The success of fully secondary recrystallization using two-stage cold rolling method is ascribed to the more important role of sufficient amount of Goss seeds in decarburized samples as in CGO steels than the stronger {111} texture as in HiB silicon steels. It is further determined that by two-stage cold rolling technique, a higher secondary stage rolling reduction leads to a lower secondary recrystallization starting temperature and a shorter secondary recrystallization staring time related with a finer grain size. The reasons for the high iron core loss related by continuous annealing are connected to the higher number of deviated Goss grains scattering toward {210} or Brass orientations, the residual inhibitors and the imperfect grain size and morphologies. The reasons for the failure in abnormal grain growth by one-stage rolling are also discussed.

Studies on interface of Cu/Al and Al/SiO2/Si

We prepared Cu/Al and Al/SiO2/Si samples by sputtering Cu on Al metals and Al on SiO2/Si, respectively. We investigated the interfaces between Cu film and Al metal, or between Al film and SiO2/Si by XPS (X-ray photoelectron spectroscopy). From the results, we found that Cu metals were oxidized in the Cu/Al samples and changed to Cu+ and Cu2+. In addition, the thickness of Cu metal in Cu/Al and Al metal in Al/SiO2/Si are thought to be less than 100 Å. At the same time, the Cu film deposited by a sputtering method may be oxidized more than the Al metal, which is prepared by the method of cold rolling. The XPS results of Al/SiO2/Si samples indicate that there may be oxygen-reduced Al2O3-x layer on the interface between Al and SiO2, and that there are inhomogeneous SiO2-x in the Ar+ etched surface of the Al/SiO2/Si sample.

Development of exoelectrogenic bioanode and study on feasibility of hydrogen production using abiotic VITO-CoRE™ and VITO-CASE™ electrodes in a single chamber microbial electrolysis cell (MEC) at low current densities

Single chamber membrane-free microbial electrolysis cell (MEC) was operated for the assessment of exoelectrogenic bacteria (EB) growth at carbon felt anode and resultant hydrogen (H2) production at abiotic cathodes, made using cold rolling (VITO-CoRE™) and casting (VITO-CASE™) methods. Progressive enrichment of EB was observed on anode during 70days of operation at an applied potential of +0.2V vs Ag/AgCl, and a maximum current density (CD) of 330.59mA/m2 (1.38mA) was recorded. H2 production at selected abiotic cathodes was observed, when the enriched bioanode was coupled to them in galvanostat mode between 0.1 and 1.0mA current range for 10min each. Higher H2 production of 114.46±3.75mL/m2 was documented with VITO-CoRE™ at 0.6mA, while 102.76±3.75mL/m2 was recorded with VITO-CASE™ at 0.8mA of current application. This study demonstrates the feasibility of H2 production on abiotic cathodes using enriched bioanode at low current densities.

Magnetic Properties and Core Loss Behavior of Fe-6.5wt.%Si Ribbons Prepared by Melt Spinning

Fe-6.5wt.%Si alloy is prepared in the form of continuous ribbons with 25 mm in width and 0.03 mm in thickness by using melt spinning technique. The ribbons are flexible and could be wounded into tapes. DC magnetic properties and core loss behaviors of the ribbons after heat treatment are investigated in this paper. The magnetic properties are compared with ribbons by cold rolling and CVD methods. The melt spinning ribbons exhibit much less core loss in the frequencies more than 10 kHz. The melt spinning ribbons are promising to be used for electric devices used in medium or higher frequencies.

Cold rolling for controllable narrowing of pore size and pore size distribution of commercial fluoroplastic microfiltration membrane

A cold-rolling method for modifying MFFK commercial microfiltration membranes based on the fluoroplastic F-42L has been developed and investigated. The method is based on the cold flow property of fluoropolymers and make it possible to alter the physical properties of a membrane without affecting its chemical structure. Scanning electron microscopy and capillary flow porometry studies have shown that this method also makes it possible to controllably narrow the through-pore diameter distribution, reduce the maximum pore size, and vary permeability depending on the applied force. In addition, rolling is a simple fluoroplastic-membrane modification process that is appropriate in engineering design and is easy to integrate into the membrane manufacturing cycle. According to available published data, this is a pioneering attempt to use the method for controllable reducing the pore diameter and narrowing the pore size distribution of fluoroplastic microfiltration membranes.

Development of a new three-stage cold rolling manufacturing technology for grain-oriented silicon steel sheets

The purpose of this paper is to present some important parameters and new results, which control various stages of the manufacturing process to obtain new grain-oriented silicon steel sheets. A three-stage cold rolling method is employed for production. The results can be used to further reduce core losses of current silicon steel sheets by additional reduction of their thicknesses or increasing the silicon content of conventional grain-oriented silicon steel sheets without problems in the cold rolling stages.

Experimental and Numerical Study on Determination of Forces During Cold Rolling of Shafts

The influence of stress and friction conditions on material flow during longitudinal cold rolling of a shaft was investigated. The longitudinal cold rolling method makes it possible to form and finish-up machine parts in the rolling process, which is associated with strengthening of the material due to cold work. The experiments were carried out in order to determine the pressure force at the stage of squeezing on shafts formed by longitudinal cold rolling and made of constructional unalloyed steels S235JR and C45. The experimental results were compared with numerical simulation results obtained by using the MSC. Marc 2010 based on finite element method (FEM). The influence of deformation degree on structural changes and the increase of material strength are shown.

Forming Principle and Error Analysis of Ballscrew Manufactured by Cold Rolling

Cold rolling is an advanced splinterless processing method, which has been applied to process many parts, like spur gears, helical gears, spline shaft and ballscrew, etc. Ballscrew which determines the motion characteristics has been used as key transmission part of ballscrew pair. According to differential geometry and meshing theory, the mathematic model of ballscrew manufactured by cold rolling is built, and the normal section equation of ballscrew is derivated in this paper. The cold forming principle of ballscrew is investigated; the meshing model, the contact line and theoretical errors of the ballscrew are constructed. The objective moving laws between roller and workpiece are revealed by analyzing the meshing model and the contact line, the processing method of cold-rolling is considered as the generating method which can lay the foundation for roller design by analyzing forming principle. By analyzing the profile error and the error of the actual helix of the centrode of ball, the error generation causes are discovered, and the calculation methods of the profile error and the spiral error of ballscrew are proposed. By analyzing the error evolution and taking a certain type of ballscrew for example, the results indicate that the profile error is brought by roller designing, and the spiral error is caused by discontinuous contact.

Hybrid super-aligned carbon nanotube/carbon black conductive networks: A strategy to improve both electrical conductivity and capacity for lithium ion batteries

Super-aligned carbon nanotube (SACNT) films drawn from SACNT arrays are uniformly introduced into LiCoO2–Super P composite cathodes by a cold-rolling method, and a hybrid conductive network consisting of SACNTs and carbon black powders is obtained. This attempt results in reduced percolation threshold and increased conductivity of the LiCoO2–Super P cathodes with addition of less than 0.01 wt% of SACNTs. The strength and flexibility of the LiCoO2–Super P–SACNT composites can be improved significantly due to the excellent mechanical properties of SACNTs. The continuous SACNT films play an important role for the formation of a homogeneous network for long-range conductive pathways. Super P is also an essential component to form short-range conductive pathways. By comparing with control samples that only contain Super P or SACNT films, we demonstrate that the LiCoO2–Super P–SACNT composites possess the best cycling stability (150 mA h g−1 at 0.1 C with a capacity retention of 99.7% after 50 cycles) and rate capability (87 mA h g−1 at 5 C). Combining both short-range and long-range conduction, the hybrid Super P-SACNT conductive network manifests itself as a promising strategy to improve the battery performances with a minimum amount of conductive fillers.

Efficient aluminum-lithium alloys 1441 and layered hybrid composites based on it

Working properties during production, structure, and physicomechanical properties of alloy 1441 sheets of the system Al–Cu–Mg–Li are described, making it possible to prepare thin sheets up to 0.3 mm thick by a coiled cold rolling method. Medium-strength (σu = 450 MPa) alloy 1441 sheet is distinguished by lower density (2.6 g/cm3), increased stiffness (E = 79 GPa), and it is used effectively in promising layered aluminum-polymer materials of the FML class for aviation structures.

Influence of deformation on the structure and properties of materials in longitudinal cold rolling of multidiameter shafts

We present the results of investigation of the influence of the level of stresses on the structure and strength of the material in the process of cold plastic deformation. The shafts subjected to testing are made by the method of longitudinal cold rolling from alloyed steel thermally improved to a hardness of HRC 34 prior to forming. It is shown that deformation affects the structure and hardness of the materials.

Polyisoprene-nanostructured carbon composite (PNCC) organic solvent vapour sensitivity and repeatability

In this paper highly structured carbon black (HSCB) dispersion method effect on polyisoprene-nanostructured carbon composite (PNCC) organic solvent vapour (OSV) sensitivity is presented. PNCC has been produced using two different HSCB dispersion techniques: (1) dry method: the HSCB dispersed in polyisoprene mixing ingredients by cold rolling and (2) wet method: the HSCB dispersed in chloroform by ultrasonic homogenizer and mixed with solution of rubber in chloroform by magnetic stirring. The sensitivity to OSV of the obtained PNCC is tested by holding the samples in vapour of toluene or ethyl acetate and measuring in situ electrical resistance, mass, and length of the sample. Obtained results indicate two mechanisms of the change of electrical resistance in PNCC. Repeatability of the response of PNCC is tested in case of toluene vapour.

Forming Principle and Error Analysis of Ballscrew Manufactured by Cold Rolling

According to differential geometry and meshing theory, the cold forming principle of ballscrew is investigated, the meshing model, the contact line and theoretical errors of the ballscrew are constructed, the objective moving laws between roller and workpiece are revealed by analyzing the meshing model and the contact line, the processing method of cold-rolling is considered as the generating method which can lay the foundation for roller design by analyzing forming principle. The error generation causes are discovered and the solutions are given by analyzing the profile error and the error of the actual helix of the centrode of ball.

Application of longitudinal cold rolling method in mass production of stepped shafts used in combustion engines

This paper presents little-known, innovative technology of cold rolling of stepped shafts. The method makes it possible to form and finish-up machine parts in the rolling process, which is associated with strengthening of material due to cold work. The author presents the results of investigations on the influence of the state of stress during cold plastic work on material's structure and its strength properties. The tests were carried out on shafts formed by longitudinal cold rolling (LCR), made of alloy steel, quenched and tempered before rolling to the hardness 34HRC. The influence of deformation degree on structural changes and increase of material strength is shown. Examples are given illustrating application of CLR technology in producing machine parts of shaft type designed for combustion engines.

Combustion Synthesis Reactions in Cold-Rolled Ni/Al and Ti/Al Multilayers

In this article, a cold rolling method was developed to fabricate Ni/Al and Ti/Al multilayer foils, and the combustion synthesis reactions in the cold-rolled foils were investigated. Combustion synthesis reactions were initiated by heating one end of the cold-rolled foil in a flame for several seconds. The Ni/Al foils went through three reaction stages. The first reaction stage was a displacement of reaction zone with Al3Ni as the reaction product. During the second stage, the part of the foil in the flame underwent thermal explosion. In the last stage, the heat released by thermal explosion triggered a self-propagating high-temperature synthesis (SHS) reaction across the foil that resulted in the formation of AlNi. In contrast, the Ti/Al foils experienced only two reaction stages. First, a displacement of the reaction zone propagated across the foil with formation of Al3Ti at the Ti/Al interface. Then a thermal explosion reaction occurred in the part of foil that was heated in the flame, resulting in many different phases in the reacted foil.

Hydrogen Permeation of Thin Pd-25Ag Membranes Prepared by Cold Rolling and Microsystem Technology

Hydrogen permeation of thin Pd-25Ag membranes with the thickness down to 1.2 mm was investigated by conventional gas permeation method within the temperature range of 473–673 K. The thin Pd-25Ag membranes with the thickness down to 51 mm were prepared by cold rolling method. The 1.2 mm-thick Pd-25Ag membrane was prepared by microsystem technology. The hydrogen permeation of the prepared Pd25Ag membranes was independent of the membrane thickness until down to 51 mm. The 51 mm-thick Pd-25Ag membrane had the hydrogen permeability lower by 60% than that of the bulk Pd-25Ag metal. It mainly resulted from slow surface reaction and lower hydrogen solubility near the surface of the 51 mm-thick Pd-25Ag membrane. The hydrogen permeability of the 1.2 mm-thick Pd-25Ag membrane was one order lower than that of bulk Pd-25Ag metal because the hydrogen permeation was mainly limited by surface reaction. However, literature review indicated that the microfabricated 1.2 mm-thick Pd-25Ag membrane had the hydrogen permeability superior to those conventional Pd-25Ag membranes supported by porous materials, suggesting attractive advantages of the microsystem technology in hydrogen-separation membrane applications. [doi:10.2320/matertrans.MRA2007260]

Effects of Tube Drawing on Structural Material for ITER Test Blanket Module

A detailed study was conducted on the first wall fabrication process using the reduced activation ferritic/martensitic steel that will be used to fabricate ITER test blanket modules. The effects of the tube-drawing process on microstructural and mechanical properties of F82H is one of the most important issues for fabrication of the module. Square tubes with □11 mm x 1.5T (thickness) mm x 3500L (length) mm have been developed by a cold-rolling method. This tube is long enough to fabricate the first wall without any joint in the cooling path. Its surface roughness (Rz) and outer curvature are less than 1 μm and 1.4 mm, respectively. Dimensions were accurate enough to reduce the assembly gap for a Hot Isostatic Pressing (HIP) joint. Although the rolling process introduced an elongated microstructure containing dense precipitates, this anisotropic microstructure was successfully recovered by heat treatments corresponding to that used in the HIP process. This work demonstrated that the drawing process could be applicable to a fabrication process for the breeding-blanket component.