Rolling Drawing Research Articles

Study on the manufacturing process of precision linear guide rail through shape rolling and shape drawing

Guide rails are one of the most important components in terms of equipment because the quality of the linear rail in-fluences on the precision linear motion. For long rails used in the guide rail, high dimensional accuracy as well as a cross-sectional shape is required. As a production method of guide rail, drawing process is mainly used. But, the shape rolling process is open used for the pre-process of the other metal forming process such as forging, extrusion, and shape drawing. The shape rolling process is one of the most effective processes which can make long products with constant irregular cross-sectional shape. Therefore, the tool shape is a very important process variable to obtain the required final product. The objective of this paper is the design of roll shape of the rolling process to produce the initial material with irregular cross sectional shape for shape drawing. Also, the die shape of the drawing process is determined to satisfy the dimensional accuracy of the final product. In this study, FE-analysis and artificial neural network (ANN) were applied to achieve the objective. Further, shape rolling and shape drawing experiments were performed to verify the result of FE-analysis. From results, it was possible to design the roll shape of shape rolling process effectively.

On the Modeling of Dual Phase Steels: Microstructure-based Simulation from the Hot Rolled Sheet to the Deep Drawn Component

A major part of the industrial development in sheet metal forming is supported by numerical simulation. While individual simulation solutions for each application are available to study the producibility or serviceability of parts, a more unified approach that considers the results from the previous step along the production chain has not been presented so far. Within a joint research project that is founded by the German Federal Ministry of Education, a simulation strategy to model the process chain of dual phase steels from the hot rolled strip up to the behavior of components under crash conditions is developed. One important aim is to close the virtual process chain that ranges from steel design to crashworthiness simulation. The proposed concept will take into account micro-structural aspects of the material as well as macroscopic approaches, depending on the process step. This contribution presents the current status of the project considering the process steps cold rolling, annealing and deep drawing.

ポリカプロラクトンのロール延伸とアルカリ処理の組合せによる皮膚線維芽細胞の接着促進効果

ポリカプロラクトンのロール延伸とアルカリ処理の組合せによる皮膚線維芽細胞の接着促進効果

Fine structure and physical properties of poly(butylene terephthalate) sheets prepared by roll drawing

AbstractPBT sheets were extruded from T-die using a single extruder and were winded by a take-up roller controlled at 50°C and with speed at 1.2 m/min. Oriented PBT sheets were prepared with various winding roll speeds at 3.6, 4.8 and 6.0 m/min. Fine structure and physical properties of PBT sheets thus obtained were investigated by measuring the molecular orientation, crystal structure, dynamic visco-elasticity, thermal and mechanical properties, sonic modulus, etc. PBT melts were found to be readily crystallizable in the sheet. In the case of roll drawing, the DRmax of PBT sheet was 5. The PBT sheets prepared from winding speed at 6 m/min showed polymorphism of both α- and β-form crystallites with crystallinity of about 24%. In the tri-directional WAXD patterns, the PBT sheets by the roll drawing method turned out to be oriented in the uniplanar-axial form. For the roll drawn PBT sheets with various winding speeds, large orientation effects were observed in the winding direction together with improved thermal and mechanical properties.

Fine structure and physical properties of poly(buthylene terephthalate) sheets prepared by roller drawing method

Poly(butylene terephthalate) sheets were prepared by roller-drawing method with various draw ratio. The drawing temperature is 100 °C and draw ratios were varied 2, 2.5, 3, 3.5 and 4. The effect of draw ratio on the crystal structure, the molecular orientation, dynamic viscoelastic properties, sonic modulus and tensile properties of the roller-drawn PBT sheets were investigated. In WAXD results, with increasing of the draw ratio, (010) and (100) planes of preferred orientation have the strongest intensity on the equator. In the meridional scans, it was confirmed that α and β crystal co-existed in the roller drawn PBT sheets with various draw ratio. Uniaxially roller-drawn PBT sheets clearly increased orientation along the stretched direction at high draw ratio. And the four-methylene groups of PBT orient along the surface of the sheet. The mechanical properties of PBT sheets were improved by orientation-induced crystallization during roller drawing process at 100 °C.

Very high modulus high‐density polyethylene and high‐modulus polypropylene obtained by solid‐state roll drawing

AbstractThis article describes results obtained with a process developed for rolling and drawing simultaneously polymer profiles in the solid state. Solid‐state roll drawing has the advantage of being continuous, which allows relatively high production rates and the generation of high deformation ratios with some degree of biaxial orientation. The roll‐drawing process allows the extent of biaxial orientation to be controlled by the adjustment of the tension and compression loads applied to the polymers, in particular semicrystalline thermoplastics. Some experimental results obtained with a four‐station roll‐drawing apparatus are presented, particularly on high‐density polyethylene (HDPE) and polypropylene. The effect of process parameters, such as the gap between the rolls and tension, are discussed. Aspects discussed also include relaxation; structure development in terms of orientation and crystallinity as a function of draw ratio (λ); λ as a function of process parameters; and finally, mechanical and thermal properties as a function of λ. Moduli as high as 25 GPa in the longitudinal direction and about 4 GPa in the transverse direction were obtained with successively rolled, initially thick, HDPE profiles. © 2006 Government of Canada. Exclusive worldwide publication right in the article have been transferred to Wiley Periodicals, Inc. J Appl Polym Sci 102: 3391–3399, 2006

Mechanical Properties and Higher Order Structures of the Bacterial Polyester Highly Oriented Films

Bacterial poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)(PHBH) highly oriented films were prepared by the combination of roll and uniaxial drawing processes. Compression molded films, which is rather brittle, turned to be ductile after roll drawing up to x 2, and the films were further uniaxially drawn to a draw ratio as high as 1000 %. The PHBH film with the tensile strength of 178 MPa and the modulus of 1.4 GPa were obtained. The roll drawn PHB film showed a slight crystalline orientation of Alpha-form. The orientation advanced with uniaxial draw ratio and the formation of Beta-form crystal was observed. Relations among the processing conditions, higher order structures and mechanical properties were investigated using wide-angle X-ray diffraction, differential scanning calorimetry, and tensile measurements.

Macroscopic damage by the formation of shear bands during the rolling and deep drawing of magnesium sheets

Most magnesium parts for automobiles are currently produced by die casting, which allows for complex geometries. However, die casting has two significant disadvantages over wrought alloy sheets: it results in poorer mechanical properties and much rougher surfaces. An alternative production route for these parts is deep-drawn and joined magnesium sheets. This article describes an investigation into the effects of the deep-drawing process on magnesium alloys.

Deformation Analysis of Surface Crack in Rolling and Wire Drawing

The surface flaw of a drawn wire has a significant influence on the quality of a product. High-surface-quality drawn wires and rods have been required for the manufacture of automobiles and machines. Wire breaks due to large surface defects are common problems in wire drawing. The authors carried out rolling and multi-pass drawing of a stainless-steel wire with an artificial scratch, and investigated the growth and disappearance of a scratch from both sides by experiments and Finite Element Analysis (FEA). When the scratch angle is small, the scratch side surfaces are pushed toward each other and the scratch becomes an overlap defect. In contrast, when the scratch angle is large, the bottom of the scratch rises, and the scratch is recovered satisfactorily. Furthermore, the scratch shape and the drawing conditions were varied, and the deformation state of a scratch was clarified.

Effect of molding temperature on crystalline and phase morphologies of HDPE composites containing PP nano-fibers

A high-density polyethylene (HDPE)/isotactic polypropylene (PP) (75/25) blend containing 25wt% of PP was fibrillated by roller drawing at 138 °C. The fibrillated blend was processed again at temperatures ranging from 155 to 200 °C by compression molding or extrusion. The effects of molding temperature on the morphology and mechanical properties of the blend were investigated. Wide angle X-ray scattering (WAXS) and transmission electron microscopy (TEM) were used to study the morphology of the samples. The roller-drawn blend exhibited a fibrous structure with the chain direction aligned parallel to the drawing direction. After molding at 155 °C, the HDPE formed parallel-stacked lamellae retaining the parallel orientation after the melting of the PE crystals. As the molding temperature increased the parallel orientation gradually vanished and some of the parallel-stacked lamellae changed into twisted lamellae. The PP phase existed as fibrils in the PE matrix and the crystals stayed with their molecular chain aligned parallel to the fibrillation direction even when the molding temperature was far above the melting temperature of PP. Nevertheless, the orientation of the crystals did not change as the molding temperature increased from 155 to 165 °C. The internal structure of the PP fibrils changed from a needle structure to a parallel-stacked one. The PP fibrils induced the crystallization of the PE melt, leading to the formation of a trans-crystalline layer at their surface. As the molding temperature increased, more PE lamellae protruded into the PP fibrils and the interface between the PP fibrils and the PE matrix became diffuse.

Upper critical field anisotropy in Nb-Ti tapes

Nb47Ti tapes were prepared with various degrees of rolling and round-wire drawing after the final heat treatment. Rolling aligned the precipitates and produced 2D behavior in several tapes, as indicated by the development of anisotropy of the upper critical field H/sub c2/. The anisotropy was observed prior to the onset of strong proximity coupling, as indicated by the change of the critical temperature T/sub c/. These different dependencies resulted in one tape having a 9.5 K T/sub c/ and a 12.3 T H/sub c2/ at 4.2 K in parallel field. Since the 2D behavior occurred prior to the optimization of flux pinning with increasing strain, the implications of 2D properties on the pinning force are discussed.

The effects of roll drawing on the structure and properties of oriented poly(ethylene terephthalate)

The effect of processing conditions on the structure and properties of roll drawn poly(ethylene terephthalate) (PET) was examined. It was found that, when roll drawing amorphous PET at temperatures just above the glass transition, only very low draw ratios were obtained. This is probably because there were no crystallites to lock in the applied extension. Roll drawing at high temperatures, above 130°C, where there was significant thermal crystallization, produced film of high strength. At temperatures between 130°C and 190°C, the properties were almost independent of processing temperature. Mechanical tests performed on roll drawn samples, processed in this temperature range, showed that the initial modulus and the yield stress increased linearly with draw ratio. The yield strain decreased with draw ratio up to λ = 4.0, and then became almost constant. The processing temperature that produced samples with the greatest strength was 170°C. This was because the highest draw ratios were obtained at this temperature while maintaining constant width deformation. At low draw ratios, the crystallinity increased with the processing, whereas at higher draw ratios, it was independent of temperature. This constant level of crystalline fraction may have produced the constant failure strain that was observed at high draw ratios. The orientation functions were similarly unaffected by the processing temperature, although birefringence measurements did suggest that lower processing temperatures may have produced higher levels of orientation. The orientation of the trans conformers was independent of the temperature, but the overall content was increased at higher processing temperatures.

High Performance Materials Obtained by Solid State Forming of Polymers

Orientation of polymers such as polyethylene (PE) by solid state extrusion near but below the melting temperature and poly(ethylene terephthalate), polyamides and poly(etheretherketone) at different temperatures by roll drawing has been performed. Draw ratio of 11 for PE and of at least 4 for the other polymers were readily achieved. For the solid state extruded material, it was observed that lubrication and geometry of the die is critical. For the roll drawn materials, tension between the rolls was very important in compensating in part for the relaxation of the material after the rolling. Slippage between the rolls was observed in all cases. From the properties point of view, an increase in the melting temperature and degree of crystallinity was observed for the oriented materials. Significant improvements in the tensile modulus and strength were observed and materials with modulus and tensile strength above 10 GPa and 500 MPa respectively were obtained. The mechanical properties can be correlated with molecular orientation. Finally, for the solid state extruded material, comparison of the experimental results in terms of the load as a function of displacement with the predictions of numerical simulations were performed and good agreement was observed.

Simulation of Rolling and Deep Drawing Textures in Ferritic Steels: Application to Ear Profile Calculation in Deep Drawing

Simulation of Rolling and Deep Drawing Textures in Ferritic Steels: Application to Ear Profile Calculation in Deep Drawing

Determination of hardness distribution in rods after combined rolling and drawing deformations

AbstractA method of computer simulation of the process of strain hardening in rods of circular cross-section subjected to deformation in a rolling–drawing process is presented. Such simulation allows the determination of the magnitude of the deformations induced by the rolling and drawing to obtain a particular cross-sectional hardness distribution in the rod. The application of this method permits, in particular, the determination of the conditions under which a rod subjected to combined rolling–drawing deformation will exhibit uniform hardness. The method was experimentally verified for Cu–30Zn rods.MST/1873

Thick textured films of Bi-type ceramics by hot pressing

Abstract Uniaxial hot pressing at various regimes of pellets, wires and tapes and multilayered structures (sandwiches) made of the commercial and own 2223 and 2212 ceramics has been performed. Incoming, tested samples have been produced by combination of cold isostatic pressing, hydrostatic extrusion, groove and flat rolling and wire drawing processes. XRD, SEM, SIMS and resistivity tests have been made. The experimental data will be discussed.

Mechanical Properties and Microstructure of Drawn High-Density Polyethylene Films by Unilateral Roller Drawing Method.

The unilateral roller-drawing (URD) method was tested to prepare high-modulus and high-strength polyethylene films. Samples were heated locally for a short period during the drawing by this method, in which only the bottom-edge of a roller was soaked with a part of the film in silicone of high temperatures. The deformation aspects of macroscopic shape and microscopic structure as well as the mechanical properties of the films drawn by the URD method were studied under the various conditions of draw-temperature (Td) and draw-ratio (λ). The values of breaking stress and Young's modulus reached 1.0GPa and 40.0GPa, respectively, at Td=120°C and λ>25. The results obtained from wide-angle X-ray diffraction indicated orientations of (110) and (200) planes as well as high degrees of c-axis orientation along the draw-direction. On the basis of small-angle X-ray scattering, it was suggested that the two-phase structure composed of crystalline and amorphous regions changed into the mono-phase structure with the extended-chain crystals when λ was increased. The folding index was evaluated from IR spectra to show that chain unfolding appreciably occurred when λ was larger than 15 and Td was in the region of between 120 and 135°C. The endothermic peak in DSC caused by the melting of the sample was found to shift to the higher temperature region with increasing λ. It was confirmed from the scanning electron microscopic observation on the fractured surface that the brittle fracture occurred for the sample drawn by the URD method, while the uniaxially cold-drawn films showed the ductile-fracture appearance. It was considered from these results that the URD method was useful to prepare high-density polyethylene films with superior mechanical properties such as high-strength and high-modulus.

Study of the Effect of Deformation on the Axes of Anisotropy

Many metal forming operations, such as rolling and tube drawing, are known to induce orthotropic anisotropy. The change of axes of orthotropy with subsequent deformation has been studied in this paper. The change in the orthotropy directions is of great importance for understanding and interpreting the subsequent yield behavior of metals. Based on Hill’s hypothesis that the orthotropy axes coincides with the principal directions of stretch, the change in orthotropy directions has been studied theoretically and experimentally. Since the grain shape and its direction of elongation is a good indicator of the principal stretches and its directions, it has been used as an experimental means of determining, not only the directions of principal stretches in an as received material, but also to determine approximately the deformation it has undergone so far from a reference state. A fully annealed isotropic state is chosen as the reference state. The directions of the axes of anisotropy, induced as a result of finite deformation applied to this reference state, are characterized in terms of the principal directions of the Cauchy’s deformation tensor. An experimental scheme has been developed to determine the varying directions of orthotropy for comparison with the theoretical model.

Preparation of in Situ Cu-Nb Composite Sheet and Wire for Tem Analysis

ABSTRACTCu-Nb in situ composites attain anomolous increases in strength upon mechanical deformation. The unique filamentary microstructures that evolve during processing (cold rolling and/or wire drawing) are the source of the strengthening. Results from transmission electron microscopy characterization studies have played a key role in the understanding of the relationships between structure and properties. However, the fabrication of reliable TEM samples has been extremely challenging for the following reasons: (1) traditional electrochemical techniques are not suitable for the two-phase microstructure, (2) preparation of longitudinal and transverse sections of fine (∼150 μm diameter wires) and thin (∼60 μm thick) sheet is tedious, and (3) it is necessary to avoid excessive heat (< 30°C) during sample preparation to preserve the metastable structural arrangements. This paper will review the procedures used to prepare TEM specimens from bulk wire and sheet samples as well as from extracted Nb filaments. Proper techniques for plating, mounting, sectioning, polishing, and ion-thinning will be discussed.

Roller drawing of polyoxymethylene

AbstractThe roller drawing of polyoxymethylene (POM) sheets was carried out in the temperature range of 140–157°C. The mechanical properties, the molecular orientation, and the microstructure of the roller‐drawn POM sheets were investigated by means of tensile test, dynamic viscoelasticity, wide‐angle X‐ray diffraction, small‐angle X‐ray scattering, visible dichroic spectrum, electron microscopy, and so on. The Young's modulus and the tensile strength increased with increasing draw ratio up to draw ratio, λ of 14–15. The improvement of the mechanical properties is concerned with structural changes, such as the increase in orientation function in the crystalline and amorphous regions and the formation of taut tie molecules and crystalline bridges in the intercrystallite and interfibrillar regions. In the higher draw ratio range (λ > 15), the increase in Young's modulus and tensile strength was restricted by the formation of interfibrillar microvoids.