Reversible Rolling Research Articles

In situ rolling circle amplification detection of Crimean Congo hemorrhagic fever virus (CCHFV) complementary and viral RNA

Crimean Congo hemorrhagic fever virus (CCHFV) is a human pathogen that causes a severe disease with high fatality rate for which there is currently no specific treatment. Knowledge regarding its replication cycle is also highly limited. In this study we developed an in situ technique for studying the different stages during the replication of CCHFV. By integrating reverse transcription, padlock probes, and rolling circle amplification, we were able to detect and differentiate between viral RNA (vRNA) and complementary RNA (cRNA) molecules, and to detect viral protein within the same cell. These data demonstrate that CCHFV nucleocapsid protein (NP) is detectable already at 6hours post infection in vRNA- and cRNA-positive cells. Confocal microscopy showed that cRNA is enriched and co-localized to a large extent with NP in the perinuclear area, while vRNA has a more random distribution in the cytoplasm with only some co-localize with NP. However, vRNA and cRNA did not appear to co-localize directly.

Computer Control System Development for the New Type Pilot Cold Rolling Mill

According to the requirement to the pilot mill for the cold rolling process research work, new type pilot reverse cold rolling mill is designed. Computer control system, including primary automation system, process automation system and human machine interface (HMI) system, is developed for this mill. Technological control function such as electric position control, hydraulic tension control, automatic gauge control (AGC), and process control functions such as model setup calculation, process tracking, actual data treatment are realized. This new type pilot cold rolling mill has been used successfully in several iron steel companies.

Temperature Field Simulation of TP2 Copper Strip during Reversible Universal Hot Rolling Using Finite Element Method

Temperature Field Simulation of TP2 Copper Strip during Reversible Universal Hot Rolling Using Finite Element Method

Temperature Field Simulation of TP2 Copper Strip during Reversible Universal Hot Rolling Using Finite Element Method

As universal hot-rolling cogging can not only make full use of the alloy’s high temperature plastic but also has the characteristic of little deformation resistance, it can provide large volumes of heavy strip. Besides，Universal hot-rolling can reduce the materias of trimming effectively and improve material utilization. At present more than 90 percent of copper and copper alloy strip are manufactured by hot-rolling. The paper presents details of simulation and analysis of 3500×980×200-size copper strip in hot rolling process by using finite element simulation technique. Particular attention is paid to predict the temperature distribution and temperature history in each pass during the process.

Research on Shape Detecting System of Cold Rolling Strip

Comprehensive considered actual working conditions of cold rolling mill, a high precision shape detecting system of cold rolling strip was developed to meet industrial application. Consideration to both follow-up processing technology requirements, dynamic flatness standard curves could be formulated according to different rolling conditions and product specifications, and reliable shape datum were provided for close-loop shape control. This system was successfully used in Angang 1250 mm HC 6-high reversible cold rolling mill. Then the shape index and the quality stability of cold rolling strip were increased significantly, the errors between the calculated values and measured values of the total tension were less than 3%, the precision of shape detecting is 0.2 I and shape indices was within 6 I after the close-loop shape control was input.

Shape Detecting and Shape Control of Cold Rolling Strip

Based on the shape detecting principle and the DSP (Digital Signal Processing) technology, a high-precision shape detecting system of cold rolling strip is developed to meet industrial application. It was successfully used in Angang 1250 mm HC 6-high reversible cold rolling mill. The precision of shape detecting was 0.2 I, the shape deviation was controlled within 6 I after the close loop shape control was input.

Effect of strain path change on the evolution of texture and microstructure during rolling of copper and nickel

The effect of strain path change during rolling has been investigated for copper and nickel using X-ray diffraction and electron back scatter diffraction as well as crystal plasticity simulations. Four different strain paths namely: (i) unidirectional rolling; (ii) reverse rolling; (iii) two-step cross rolling and (iv) multi-step cross rolling were employed to decipher the effect of strain path change on the evolution of deformation texture and microstructure. The cross rolled samples showed weaker texture with a prominent Bs {1 1 0}〈1 1 2〉 and P(BND) {1 1 0}〈1 1 1〉 component in contrast to the unidirectional and reverse rolled samples where strong S {1 2 3}〈6 3 4〉 and Cu {1 1 2}〈1 1 1〉 components were formed. This was more pronounced for copper samples compared to nickel. The cross rolled samples were characterized by lower anisotropy and Taylor factor as well as less variation in Lankford parameter. Viscoplastic self-consistent simulations indicated that slip activity on higher number of octahedral slip systems can explain the weaker texture as well as reduced anisotropy in the cross rolled samples.

Development of Pass Schedule Calculation Procedure for Single-Stand Reversing Cold Rolling Mill

In this paper, pass schedule calculation method for single-stand reversing cold rolling mill is introduced. Newton－Rapshon method is used to solve non-linear equations composed of each pass loads according to equal power rolling strategy. After the thickness of each pass is calculated, rolling parameters of each pass is obtained by modification. Based on the method pass schedule calculation procedure is developed. The practical application shows that calculation result of program is close to the actual data, and the speed and stability of the procedure can meet the requirement of on-line process control, so it is suitable for the single-stand reversible cold rolling mill.

Improvement of Surface Densification and Fatigue Strength by Tooth Root Rolling of Sintered Ferrous Alloy Gear Added Mo

Surface rolling were carried out using P/M spur gears of 0.6Mo-0.2C partially alloyed sintered steel with the density of 7.18 g/cm3. A CNC form rolling machine of axis intersection type was employed, and an unmodified screw-shaped rolling tool was prepared. Then, porosity distributions in the surface layer of rolled gear teeth root were measured and the effects of the surface rolling on the selective surface densification behaviors were evaluated. Moreover, to obtain higher fatigue strength, reverse rolling was introduced to standard gears. As a result, the porosities in the tooth root were sufficiently reduced at 700 μm feed in rolling process. Furthermore, a profile shifted gear was prepared to increase the effect of surface rolling. After case hardening, the single tooth bending fatigue durability reached to about 83 % of the case hardened wrought steel gears of SCM415.

Ongoing Walking Recovery 2 Years After Locomotor Training in a Child With Severe Incomplete Spinal Cord Injury

The authors previously reported on walking recovery in a nonambulatory child with chronic, severe, incomplete cervical spinal cord injury (SCI) after 76 sessions of locomotor training (LT). Although clinical measures did not predict his recovery, reciprocal patterned leg movements developed, affording recovery of independent walking with a reverse rolling walker. The long-term functional limitations and secondary complications often associated with pediatric-onset SCI necessitate continued follow-up of children with SCI. Therefore, the purpose of this case report is to describe this child's walking function and musculoskeletal growth and development during the 2 years since his participation in an LT program and subsequent walking recovery. Following LT, the child attended elementary school as a full-time ambulator. He was evaluated 1 month (baseline), 1 year, and 2 years after LT. Examination of walking function included measures of walking independence, gait speed and spatiotemporal parameters, gait kinematics, and daily step activity. Growth and development were assessed by tracking his height, weight, incidence of musculoskeletal complications, and gross motor task performance. Over the 2 years, the child continued to ambulate independently with a reverse rolling walker, increasing his fastest gait speed. Spatiotemporal and kinematic features of his walking improved, and daily step activity increased. Height and weight remained on their preinjury trajectory and within age-appropriate norms. The child experienced only minor musculoskeletal complications. Additionally, he gained the ability to use reciprocal patterned leg movements during locomotor tasks such as assisted stair climbing and independent tricycle pedaling. Two years after recovery of walking, this child with incomplete SCI had maintained and improved his walking function and experienced age-appropriate growth and development.

Design of a fault diagnosis system based on a bank of filter—observers with application to a hot rolling mill

This paper proposes a new method for actuator/sensor faults detection, isolation and magnitude estimation. By establishing new theoretical results relating to fault diagnosis and by defining a specific application domain, the research work described in this paper aims at developing a model-based fault detection filter combined with a conventional Luenberger observer. Based on an appropriate gain, the developed technique enables one to supervise a system through an accurate bank of residuals within a generalized observer scheme. The approach is evaluated by diagnosing a series of actuator/sensor faults in a speed control loop of a hot rolling mill used to carry out multi-pass forward—forward or forward—reverse rolling. The performance of the technique is illustrated via a wide range of simulations in the ‘faulty’ case and a practical experiment in the ‘fault-free’ case using a real rolling mill.

Constituent Particle Break‐Up During Hot Rolling of AA 5182

AbstractAluminum sheet is currently used for body panels on a number of mass‐produced vehicles, in particular for closure panels. AA5xxx alloys always contain coarse inter‐metallic particles (Alx(Fe,Mn)ySi, Mg2Si) after casting. In the present work inter‐metallic particle break‐up during hot reversible rolling of AA5182 alloy sheets has been analyzed. The sizes and shapes of inter‐metallic particles in as‐cast and industrially hot rolled AA5182 alloys sheets were characterized by 3D X‐ray tomography observations. The relation between particle break‐up and particle morphology was then analyzed statistically and by a micromechanical finite element (FE)‐based model. The essential outcomes of the statistical approach may be summarized as follows. The inter‐metallic particle population may be described by five morphological parameters. Secondly the comparison of the particle morphology in as cast and industrially rolled sheets leads to the definition of five classes. The evolution of each particle class as function of the rolling strain is provided. The statistical analysis shows which particles break‐up. The stresses and strains in inter‐metallic particles, embedded in an elasto‐viscoplastic aluminum matrix submitted to plane strain compression, were analyzed by an FE model. A new failure criterion was proposed. The essential outcomes of the mechanical approach are as follows: a precise description of stress concentration mechanisms in nonconvex particles, a close description of the parameters controlling particle break‐up, and finally a simplified classification of the failure behavior.

Adaptive Automatic Gauge Control of a Cold Strip Rolling Process

The paper tackles with thickness control structure of the cold rolled strips. This structure is based on the rolls position control of a reversible quarto rolling mill. The main feat ...

Temperature controlled encapsulation and release using partially biodegradable thermo-magneto-sensitive self-rolling tubes

We suggest a new approach for controlled encapsulation and release of microparticles, cells and drugs using thin bilayer films of thermoresponsive and biodegradable polymers, which are able to form self-rolling tubes. The magnetic nanoparticles are incorporated in the thermoresponsive layer in order to provide the microtubes sensitivity to magnetic field. We demonstrate reversible rolling and unrolling of the polymer films, reversible capture and release of microparticles in response to change of temperature as well as manipulation of particle-loaded microtubes using external magnetic field. The suggested approach can be successfully implemented for controlled delivery of drugs and cells in living organisms as well as to design scaffolds for tissue engineering.

Enhanced stretch formability of Mn-free AZ31 Mg alloy rolled by cross-roll rolling

Stretch formability of a Mn-free AZ31 Mg alloy rolled by the reverse cross-roll rolling was investigated at room temperature. The specimen rolled by the reverse cross-roll rolling showed superior stretch formability to that of the reference specimen. The (0002) plane texture of the specimen by the revere cross-roll rolling exhibited a low texture intensity and a circular spread of the basal pole from the ND compared with those of the reference specimen. It is suggested that the modification of basal texture by the reverse cross-roll rolling contributes to an activation of basal slip and twinning, resulting in an enhancement of the thickness-direction strain and tensile ductility. Besides, it is suggested that the coarse grain size of a Mn-free AZ31 alloy seems to enhance a stretch formability, because twins become easily generated during loading.

Three-dimensional numerical simulation of the edger and corner metal’s flow on edging rolling on roughing of hot continuous rolling process

Based on the seam-defect appearing on the plate edge of rough-rolling medium billet in the Meishan Iron and Steel Companys hot-rolling units, the five-pass reversible vertical-horizontal rolling of different vertical roll shapes process is simulated numerically. The results show that groove vertical rolls rolling can inhibit double bulging deformation better. On the same rolling process conditions, the value of side tumbling on groove vertical rolling is larger than that on flat vertical rolling, and the value of side tumbling increases with the groove fillet radius increasing. During the rolling process, that the metal at low temperature, high strain and high stress cumulates on the edge of the workpiece may bring the seam-defect along the length of the workpiece. The edge interlayers could be avoided by reasonably designing the vertical roll shape and optimizing the vertical rolls screw system, thereby reducing or avoiding the occurrence of seam-defects.

Stress concentrations in non-convex elastic particles embedded in a ductile matrix

Aluminium sheet is currently used for body panels on a number of mass-produced vehicles, in particular for closure panels. AA5xxx alloys always contain coarse inter-metallic particles (Al x(Fe,Mn) ySi, Mg 2Si) after casting, undesirable for the final sheet forming and stamping operations. In the present work inter-metallic particle break-up during hot reversible rolling of AA5182 alloy sheets has been analysed by both experiments and by a micromechanical model. The sizes and shapes of inter-metallic particles in as cast and industrially hot rolled AA5182 alloys sheets were characterised by 3D X-ray tomography observations. The evolution of inter-metallic particle size and shape vs. hot rolling deformation was studied. The stresses and strains in inter-metallic particles, embedded in an elasto-viscoplastic aluminium matrix submitted to plane strain compression, were analysed by a finite element (FE) model. First, the mechanisms leading to stress and strain concentrations were analysed on several model particle shapes. A new algorithm for FE-analysis of stress concentrations around hard second phase particles in Al alloys was developed. A new failure criterion for brittle pre-cracked solids embedded in a soft matrix submitted to large straining was proposed. Secondly, this new algorithm and the new failure criterion were used to analyse the stress and strain concentrations in the real particles observed by X-ray tomography. The ability to break-up of the particles was analysed. The essential outcomes of the present work are as follows: a precise description of stress concentration mechanisms in non-convex particles, a new failure criterion based on the comparison between an active and a critical volume, a close description of the parameters controlling particle break-up, and finally a classification of the failure behaviour of real inter-metallic particles.

Experimental study for roll gap adjustment due to roll wear in single-stand rolling and multi-stand rolling test

To investigate a correlation between the amount of wear and roll gap (pass height) adjustment, we performed a single-stand reversible pilot groove rolling test as well as rolling test in an actual rod mill. In case of the pilot rolling test, we designed wear contour (profile) and machined it on the original roll groove (i.e., roll groove with no wear) to make the roll groove worn down. For the actual rod mill test, we developed a measuring device which can detect the actual wear profile.

Modelling and simulation of MIMO non-linear systems web winding system of a reversible rolling mill

This work treats the modelling and the simulation of the non-linear dynamic behaviour of a web winding process during traction and by consideration the variations of the radius and inertia rollers. We designate by a winding process any system applying the cycles of unwinding, transport, treatment and winding to various flat products. This system knows several constraints such as the thermal effects caused by the frictions, and the mechanical effects provoked by metal elongation, that generates dysfunctions due to the influence of the process conditions. Our study is relative to the modelling and the identification of the parameters of a Web Winding System (WWS) of a reversible mill. Modelling is based on the general laws of physics laws using the strip elasticity, frictions between strip and rolls and the flow of strip between two rolls. Our goal is the determination of the strip tension in movement and the strip velocity in order to synthesise the coupling between variables. Because of the important variation of the radius and inertia of the rolls, the system dynamics change considerably during the winding/unwinding process. Thus, the stability and performances of system are studied on different range of radius variation. The modelling conditions are specified and a mathematical model is presented. Numerical results are exposed and discussed.

A numerical approach to determine flow stress–strain curve of strip and friction coefficient in actual cold rolling mill

Abstract An inverse scheme-based approach for the prediction of flow stress–strain curve and friction coefficient using actual mill data is presented. The equations for roll force and forward slip are selected as the basic ones. Then they are inverted such that the deformation resistance and friction coefficient can be expressed as a function of process parameters measurable during rolling such as strip width, entrance and delivery thickness, forward and backward tensile stress, forward slip, roll force and roll diameter. A procedure for solving the inverse equations is described in detail. It includes steps which solve non-linear equation and generate the flow stress–strain curve from the data set of deformation resistances using the least square method. The capability of the present approach is verified by applying it to a reversible cold rolling mill. A good agreement is noted between the predicted flow stress–strain curve and the measured one.