Texture and mechanical properties evolution of a deep drawing medium carbon steel during cold rolling and subsequent recrystallization

Medium carbon steels are mostly used for simple applications; however, new applications have been developed for which good sheet metal formability is required. These types of steels have an inherent low formability. A medium-carbon hot-rolled SAE 1050 steel was selected for this study. It has been cold rolled with thickness reductions varying between 7 and 80%. The samples obtained were used to evaluate the strain hardening curve. For samples with a 50 and 80% thickness reduction, an annealing heat treatment was performed to achieve recrystallization. The material was characterized in the ""as-received"", cold rolled and annealed conditions using several methods: optical metallography, X-ray diffraction (texture), Vickers hardness, and tensile testing. For large thickness reductions, the SAE 1050 steel presented low elongation, less than 2%, and yield strength (YS) and tensile strength (TS) around 1400 MPa. Texture in the ""as-received"" condition showed strong components on the {001} plane, in the < 100 >, < 210 > and (110) directions. After cold rolling, the texture did not present any significant changes for small thickness reductions, however. It changed completely for large ones, where gamma, < 111 >//ND, alpha, < 110 > HRD, and gamma prime, < 223 >//ND, fibres were strengthened. After annealing, the microstructure of the SAE 1050 steel was characterized by recrystallized ferrite and globular cementite. There was little change in the alpha fibre for the 50% reduction, whereas for the 80% reduction, its intensity increased. Both gamma and gamma prime fibres vanished upon annealing for 50 and 80% reductions alike. (c) 2008 Elsevier B.V. All rights reserved.

Medium carbon steel deep drawing: A study on the evolution of mechanical properties, texture and simulations, from cold rolling to the end product

Medium carbon steels are mostly used for simple applications; nevertheless new applications have been developed for which good sheet formability is required. This class of steels has an inherent low formability. A medium carbon hot rolled SAE 1050 steel has been selected for this study. It has been cold rolled with reductions in the 7-80% range. Samples have been used to assess the cold work hardening curve. For samples with a 50 and 80% thickness reduction, an annealing heat treatment has been performed to obtain recrystallization. The material has been characterized in the ""as received"", cold rolled and annealed conditions, using several methods: optical microscopy, X-ray diffraction (texture), Vickers hardness and tensile testing. The 50% cold rolled and recrystallized material has been further studied in terms of sheet metal formability and texture evolution during the actual stamping of a steel toecap that has been used to validate the finite element simulations. (C) 2008 Elsevier B.V. All rights reserved.

Effect of rolling on the residual stresses and magnetic properties of a 0.5% Si electrical steel

Cold-rolled (0-19% of reduction) 0.5% Si electrical steel sheets were studied in detail, including macro and micro residual stress measurements, crystallographic texture, dc-hysteresis curves and iron losses. Even for the smallest deformation, losses increase significantly, with large increase of the hysteresis losses, whereas the anomalous losses reduce slightly. The residual microstresses are similar to 150-350 MPa, whereas residual macrostresses are compressive, similar to 50 MPa. The large increase of the hysteresis losses is attributed to the residual microstresses. The dislocation density estimated by X-ray diffraction is in reasonable agreement with that predicted from the Sablik et al. model for effect of plastic deformation on hysteresis. The intensity of the texture fibers {1 1 1}< u v w > and < 110 >//RD (RD = rolling direction) increases with the reduction. (C) 2008 Elsevier B.V. All rights reserved.

Adequacy of Cold Rolling Models to Upgrade Set-up Generation Systems

This paper presents two strategies for the upgrade of set-up generation systems for tandem cold mills. Even though these mills have been modernized mainly due to quality requests, their upgrades may be made intending to replace pre-calculated reference tables. In this case, Bryant and Osborn mill model without adaptive technique is proposed. As a more demanding modernization, Bland and Ford model including adaptation is recommended, although it requires a more complex computational hardware. Advantages and disadvantages of these two systems are compared and discussed and experimental results obtained from an industrial cold mill are shown.

An anti-inflammatory lectin from Luetzelburgia auriculata seeds inhibits adhesion and rolling of leukocytes and modulates histamine and PGE2 action in acute inflammation models

To study and characterize the in vivo effect of the lectin from Luetzelburgia auriculata seed on acute inflammation models. The lectin was purified from the crude saline extract by affinity chromatography on a guar-gum matrix. Native, heat-treated, and digested lectin was evaluated for anti-inflammatory activity by using peritonitis and paw edema models. The anti-inflammatory activity was characterized by intravital microscopy, nitric oxide production, and myeloperoxidase activity. The lectin exhibited anti-inflammatory activity (2 mg/kg) on both models, reducing local myeloperoxidase activity. Galactose or heat treatment (100A degrees C, 10 min) reduced anti-inflammatory action. Anti-inflammation involves the inhibition of adhesion and rolling of leukocytes along with augmentation of nitric oxide in serum. The lectin inhibited the edematogenic effect of histamine and prostaglandins (PGE2) but did not alter the chemoattractant effect of IL-8. The results indicate that this lectin is a potent anti-inflammatory molecule. Its effects engage diverse modulatory events.

Involvement of NO in the inhibitory effect of Calotropis procera latex protein fractions on leukocyte rolling, adhesion and infiltration in rat peritonitis model

Aim of the study: The latex of Calotropis procera has been used in the traditional medicinal system for the treatment of leprosy, ulcers, tumors, piles and diseases of liver, spleen, abdomen and toothache. it comprises of a non-dialyzable protein fraction (LP) that exhibits anti-inflammatory properties and a dialyzable fraction (DF) exhibiting pro-inflammatory properties. The present study was carried out to evaluate the effect of LP sub-fractions on neutrophil functions and nociception in rodent models and to elucidate the mediatory role of nitric oxide (NO). Material and methods: The LP was subjected to ion exchange chromatography and the effect of its three sub-fractions (LP(PI), LP(PII), and LP(PIII)) thus obtained was evaluated on leukocyte functions in the rat peritonitis model and on nociception in the mouse model. Results: LP sub-fractions exhibit distinct protein profile and produce a significant decrease in the carrageenan and DF induced neutrophil influx and exhibit anti-nociceptive property. The LP and its sub-fractions produced a marked reduction in the number of rolling and adherent leukocytes in the mesenteric microvasculature as revealed by intravital microscopy. The anti-inflammatory effect of LP(PI), the most potent anti-inflammatory fraction of LP, was accompanied by an increase in the serum levels of NO. Further, our study shows that NO is also involved in the inhibitory effect of LP(PI) on neutrophil influx. Conclusions: Our study shows that LP fraction of Calotropis procera comprises of three distinct sets of proteins exhibiting anti-inflammatory and anti-nociceptive properties of which LP(PI) was most potent in inhibiting neutrophil functions and its effects are mediated through NO production. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Vibration instability in rolling mills: Modeling and experimental results

Models for the occurrence of the vibrational instability during rolling known as third octave chatter are presented and discussed. An analysis of rolling mill chatter was performed for the purpose of identifying characteristics of the vibrations and to determine any dependency on the rolling schedule. In particular, a stability criterion for the critical rolling speed is used to predict the maximum rolling speed without chatter instability on schedules from a 5 stand tandem mill rolling thin steel product. The results correlate well with measurements of critical speed occurring on the mill using a vibration monitor: This research provides significant insights into the chatter phenomena and has been used to investigate control methods for suppression of the instability.

Statistical classification of road pavements using near field vehicle rolling noise measurements

Low noise surfaces have been increasingly considered as a viable and cost-effective alternative to acoustical barriers. However, road planners and administrators frequently lack information on the correlation between the type of road surface and the resulting noise emission profile. To address this problem, a method to identify and classify different types of road pavements was developed, whereby near field road noise is analyzed using statistical learning methods. The vehicle rolling sound signal near the tires and close to the road surface was acquired by two microphones in a special arrangement which implements the Close-Proximity method. A set of features, characterizing the properties of the road pavement, was extracted from the corresponding sound profiles. A feature selection method was used to automatically select those that are most relevant in predicting the type of pavement, while reducing the computational cost. A set of different types of road pavement segments were tested and the performance of the classifier was evaluated. Results of pavement classification performed during a road journey are presented on a map, together with geographical data. This procedure leads to a considerable improvement in the quality of road pavement noise data, thereby increasing the accuracy of road traffic noise prediction models.

Angular and linear accelerations of a rolling cylinder acted by an external force

The dynamics of a cylinder rolling on a horizontal plane acted on by an external force applied at an arbitrary angle is studied with emphasis on the directions of the acceleration of the centre-of-mass and the angular acceleration of the body. If rolling occurs without slipping, there is a relationship between the directions of these accelerations. If the linear acceleration points to the right, then the angular acceleration is clockwise. On the other hand, if it points to the left, then the angular acceleration is counterclockwise. In contrast, if rolling and slipping occurs, the direction of the linear acceleration does not determine the direction of the angular acceleration. For example, the linear acceleration may point to the right and the angular acceleration clockwise or counterclockwise depending on the external force orientation and point of application.

Experimental measuring procedure for the friction torque in rolling bearings

The reduction of the power loss generated in mechanical transmissions and the use of low friction biodegradable lubricants has been attracting considerable attention in recent times. Therefore, it is necessary to develop methods to test and evaluate the performance of such lubricants and compare them with conventional ones. In this sense, a Four-Ball Machine was modified allowing the test of rolling bearings. A 51107 thrust ball bearing was used to test two different greases and the corresponding base oils. Friction torque and operating temperatures were continuously monitored to quantify the power loss and the heat evacuation for each lubricant tested. Copyright © 2010 John Wiley & Sons, Ltd.

Four new species of Wing Rolling Neodawnaria (Homoptera : Derbidae) from the Amazon Basin

Four new species of Neidawnaria are described, and compared with other members of the genus. Keys and geographical distribution are given for all nem species and the wings of two other species are illustrated.

Multidisziplinäre Modellierung und Simulation eines Rolling Rotor Switched Reluktanz Antriebes

Magdeburg, Univ., Fak. für Maschinenbau, Diss., 2012

Ezrin-Radixin-Moesin-binding Sequence of PSGL-1 Glycoprotein Regulates Leukocyte Rolling on Selectins and Activation of Extracellular Signal-regulated Kinases.

P-selectin glycoprotein ligand-1 (PSGL-1) mediates the capture (tethering) of free-flowing leukocytes and subsequent rolling on selectins. PSGL-1 interactions with endothelial selectins activate Src kinases and spleen tyrosine kinase (Syk), leading to α(L)β(2) integrin-dependent leukocyte slow rolling, which promotes leukocyte recruitment into tissues. In addition, but through a distinct pathway, PSGL-1 engagement activates ERK. Because ezrin, radixin and moesin proteins (ERMs) link PSGL-1 to actin cytoskeleton and because they serve as adaptor molecules between PSGL-1 and Syk, we examined the role of PSGL-1 ERM-binding sequence (EBS) on cell capture, rolling, and signaling through Syk and MAPK pathways. We carried out mutational analysis and observed that deletion of EBS severely reduced 32D leukocyte tethering and rolling on L-, P-, and E-selectin and slightly increased rolling velocity. Alanine substitution of Arg-337 and Lys-338 showed that these residues play a key role in supporting leukocyte tethering and rolling on selectins. Importantly, EBS deletion or Arg-337 and Lys-338 mutations abrogated PSGL-1-induced ERK activation, whereas they did not prevent Syk phosphorylation or E-selectin-induced leukocyte slow rolling. These studies demonstrate that PSGL-1 EBS plays a critical role in recruiting leukocytes on selectins and in activating the MAPK pathway, whereas it is dispensable to phosphorylate Syk and to lead to α(L)β(2)-dependent leukocyte slow rolling.

Endoglycan mediates malignant leukocyte rolling on e-selectin and signals through SYK and the MAPK pathway

Selectins play a key role regulating leukocyte migration into tissues by mediating leukocyte tethering (capture) and rolling on inflamed endothelium and/or on adherent leukocytes or platelets. During leukocyte rolling, endothelial E- or P-selectin bind to glycoprotein ligands carrying sialyl Lewis χ (sLex) determinant. P-selectin glycoprotein ligand-1 (PSGL-1) is a common ligand for L-, P- and E-selectin, which sequentially cooperates with CD44 and E- selectin ligand-1 (ESL-1) to roll on E-selectin. During rolling on endothelial selectins, PSGL-1 and CD44 signal through Src family kinases and Syk, leading to αι_β2 integrin partial activation and slow rolling on intercellular adhesion molecule-1 (ICAM-1). Leukocyte exposure to chemokines then leads to firm adhesion. Little information is available on ligands that mediate malignant leukocyte rolling on E- selectin. We defined these ligands on U937 monoblasts by immunoadsorbtion and immunoblotting using mAb raised against CD43, CD44, PSGL-1, sLex/CLA determinants and E-selectin/IgM chimera. Immunoblotting and blot rolling assays demonstrated that PSGL-1, CD43, CD44 and a -125 kDa sLex/CLA positive ligand contribute to support E-seiectin- dependent rolling. This -125 kDa ligand is endoglycan, a member of the CD34 family of sialomucins. Endoglycan was frequently detected by flow cytometry on primary leukemia, lymphoma and multiple myeloma ceils (in -50% of cases). Endoglycan, immunopurified from U937 cells, as well as endoglycan/IgG chimera efficiently supported E-selectin dependent rolling. Membrane fractionation on sucrose gradient demonstrated that endoglycan is expressed in lipid rafts. We tested the hypothesis that it signals, like PSGL-1 and CD44, through Src kinases and the MAPK pathway. Indeed, endoglycan engagement induced Syk and ERK phosphorylation in a iipid raft-dependent manner. Syk activation was dependent on Src kinase activity. Downstream of Syk, endoglycan activated PI3K and Akt as well as Bruton's tyrosine kinase and p38 MAPK. Thus, endoglycan is a ligand for endothelial selectins which may contribute to regulate leukemia, lymphoma and multiple myeloma cell trafficking and interactions with bone marrow microenvironment. - Les sélectines contrôlent la migration tissulaire des leucocytes en assurant leur capture et leur roulement sur l'endothélium vasculaire enflammé et/ou sur des plaquettes ou des leucocytes adhérant à la paroi vasculaire. Lors du roulement leucocytaire, les sélectines endothéliales (E- et P-sélectine) se lient à des ligands porteurs du saccharide sialyl Lewis χ (sLex). PSGL-1 est un ligand commun des sélectines qui coopère avec CD44 et ESL-1 pour permettre la capture et le roulement des neutrophiles. Lorsque PSGL-1 et CD44 se lient aux sélectines endothéliales, elles induisent la phosphorylation des kinases Src et de Syk conduisant à l'activation partielle de l'intégrine aLp2 et au ralentissement des leucocytes sur les sélectines et ICAM-1. Les chimiokines induisent ensuite l'adhésion ferme des leucocytes. Les ligands des sélectines qui assurent le roulement, sur la E-sélectine, des cellules issues d'hémopathies malignes sont peu connus. Nous avons caractérisé ces ligands en les purifiant avec des anticorps dirigés contre CD43, CD44, PSGL-1, sLex/CLA et en utilisant la chimère E-sélectine/IgM. Des tests d'adhésion ont montré que PSGL-1, CD43, CD44 et une glycoprotéine de ~125 kDa soutiennent les interactions cellulaires dépendant de la E- sélectine. Le ligand de -125 kDa a été identifié comme étant l'endoglycan. Il a été détecté, par cytométrie de flux, sur les cellules leucémiques, les cellules de lymphomes ou de myélome multiple, dans ~50% des cas analysés. Sa forme membranaire, immunopurifiée, ou recombinante (endoglycan/lgG) soutient les interactions cellulaires dépendant de la E- sélectine. Nous avons montré qu'il réside dans les rafts lipidiques membranaires puis avons testé l'hypothèse que l'endoglycan, comme PSGL-1 et CD44, induit une signalisation via les kinases de type Src et la voie des MAPK. Nous avons pu observer que son engagement induit la phosphorylation de Syk et de ERK pour autant que la structure des rafts soit préservée. En aval de Syk, l'endoglycan active la PI3K, Akt, Btk et la MAPK p38. Ces résultats montrent que l'endoglycan est un ligand des sélectines endothéliales qui pourrait participer au contrôle du trafic et des interactions des cellules leucémiques, de lymphomes ou de myélomes multiples avec leur microenvironnement. - Le sang est un élément clé du fonctionnement de notre corps. La circulation sanguine permet la communication et le transfert de molécules et cellules entre divers organes. Lors d'une inflammation aiguë due à une réaction allergique, une infection ou une blessure, on observe un oedème local accompagné de rougeur, de chaleur et souvent de douleurs. Au sein des tissus enflammés, on observe des globules blancs (leucocytes) et diverses molécules inflammatoires qui attirent les leucocytes dans les tissus lésés (chimiokines). Le sang est composé de globules rouges, de plaquettes et de leucocytes spécialisés dans les défenses immunes. Pour atteindre le site d'inflammation, les leucocytes doivent quitter la circulation sanguine. Ils utilisent pour cela des molécules d'adhésion présentes à leur surface qui se lient à d'autres molécules d'adhésion de la paroi sanguine. Leurs interactions permettent aux leucocytes de rouler à la surface du vaisseau sanguin. Lorsqu'ils roulent au voisinage d'un site d'inflammation, les leucocytes sont exposés à des chimiokines qui induisent leur arrêt et les dirigent dans les tissus enflammés. Ce processus physiologique est aussi impliqué dans des pathologies telles que l'infarctus, l'artériosclérose ou la thrombose. Il peut être détourné à des fins moins louables par des cellules cancéreuses pour permettre leur dissémination (métastatisation). Dans ce travail de thèse, nous avons caractérisé une molécule d'adhésion qui soutient l'adhésion des leucocytes aux sélectines endothéliales: l'endoglycan. Nous avons observé que cette molécule d'adhésion est fréquemment exprimée par les cellules malignes de nombreuses maladies du sang comme les leucémies, les lymphomes et le myélome multiple. Nous avons également pu montrer que l'endoglycan envoie des signaux à l'intérieur des cellules malignes lorsqu'elles se lient aux sélectines endothéliales. Ces signaux pourraient jouer un rôle déterminant dans la régulation des interactions des cellules malignes avec leur microenvironnement. Elles pourraient peut-être aussi favoriser leur survie et leur prolifération.

P-selectin glycoprotein ligand-1 decameric repeats regulate selectin-dependent rolling under flow conditions.

P-selectin glycoprotein ligand-1 (PSGL-1) interacts with selectins to support leukocyte rolling along vascular wall. L- and P-selectin bind to N-terminal tyrosine sulfate residues and to core-2 O-glycans attached to Thr-57, whereas tyrosine sulfation is not required for E-selectin binding. PSGL-1 extracellular domain contains decameric repeats, which extend L- and P-selectin binding sites far above the plasma membrane. We hypothesized that decamers may play a role in regulating PSGL-1 interactions with selectins. Chinese hamster ovary cells expressing wild-type PSGL-1 or PSGL-1 molecules exhibiting deletion or substitution of decamers with the tandem repeats of platelet glycoprotein Ibalpha were compared in their ability to roll on selectins and to bind soluble L- or P-selectin. Deletion of decamers abrogated soluble L-selectin binding and cell rolling on L-selectin, whereas their substitution partially reversed these diminutions. P-selectin-dependent interactions with PSGL-1 were less affected by decamer deletion. Videomicroscopy analysis showed that decamers are required to stabilize L-selectin-dependent rolling. Importantly, adhesion assays performed on recombinant decamers demonstrated that they directly bind to E-selectin and promote slow rolling. Our results indicate that the role of decamers is to extend PSGL-1 N terminus far above the cell surface to support and stabilize leukocyte rolling on L- or P-selectin. In addition, they function as a cell adhesion receptor, which supports approximately 80% of E-selectin-dependent rolling.