Manufacturing and properties of closure head forging integrated with flange for PWR reactor pressure vessel

International Nuclear Information System (INIS)

Tomoharu Sasaki; Iku Kurihara; Etsuo Murai; Yasuhiko Tanaka; Koumei Suzuki

2003-01-01

Closure head forging (SA508, Gr.3 Cl.1) integrated with flange for PWR reactor pressure vessel has been developed. This is intended to enhance structural integrity of closure head resulted in elimination of ISI, by eliminating weld joint between closure head and flange in the conventional design. Manufacturing procedures have been established so that homogeneity and isotropy of the material properties can be assured in the closure head forging integrated with flange. Acceptance tensile and impact test specimens are taken and tested regarding the closure head forging integrated with flange as very thick and complex forgings. This paper describes the manufacturing technologies and material properties of the closure head forging integrated with flange. (orig.)

Simulation and analysis of hot forging process for industrial locking gear elevators

Science.gov (United States)

Maarefdoust, M.; Kadkhodayan, M.

2010-06-01

In this paper hot forging process for industrial locking gear elevators is simulated and analyzed. An increase in demand of industrial locking gear elevators with better quality and lower price caused the machining process to be replaced by hot forging process. Production of industrial locking gear elevators by means of hot forging process is affected by many parameters such as billet temperature, geometry of die and geometry of pre-formatted billet. In this study the influences of billet temperature on effective plastic strain, radius of die corners on internal stress of billet and thickness of flash on required force of press are investigated by means of computer simulation. Three-dimensional modeling of initial material and die are performed by Solid Edge, while simulation and analysis of forging are performed by Super Forge. Based on the computer simulation the required dies are designed and the workpieces are formed. Comparison of simulation results with experimental data demonstrates great compatibility.

Practicable methods for histological section thickness measurement in quantitative stereological analyses.

Science.gov (United States)

Matenaers, Cyrill; Popper, Bastian; Rieger, Alexandra; Wanke, Rüdiger; Blutke, Andreas

2018-01-01

The accuracy of quantitative stereological analysis tools such as the (physical) disector method substantially depends on the precise determination of the thickness of the analyzed histological sections. One conventional method for measurement of histological section thickness is to re-embed the section of interest vertically to its original section plane. The section thickness is then measured in a subsequently prepared histological section of this orthogonally re-embedded sample. However, the orthogonal re-embedding (ORE) technique is quite work- and time-intensive and may produce inaccurate section thickness measurement values due to unintentional slightly oblique (non-orthogonal) positioning of the re-embedded sample-section. Here, an improved ORE method is presented, allowing for determination of the factual section plane angle of the re-embedded section, and correction of measured section thickness values for oblique (non-orthogonal) sectioning. For this, the analyzed section is mounted flat on a foil of known thickness (calibration foil) and both the section and the calibration foil are then vertically (re-)embedded. The section angle of the re-embedded section is then calculated from the deviation of the measured section thickness of the calibration foil and its factual thickness, using basic geometry. To find a practicable, fast, and accurate alternative to ORE, the suitability of spectral reflectance (SR) measurement for determination of plastic section thicknesses was evaluated. Using a commercially available optical reflectometer (F20, Filmetrics®, USA), the thicknesses of 0.5 μm thick semi-thin Epon (glycid ether)-sections and of 1-3 μm thick plastic sections (glycolmethacrylate/ methylmethacrylate, GMA/MMA), as regularly used in physical disector analyses, could precisely be measured within few seconds. Compared to the measured section thicknesses determined by ORE, SR measures displayed less than 1% deviation. Our results prove the applicability

Assessment of residual stress of 7050-T7452 aluminum alloy forging using the contour method

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zheng [College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Yang, Yinfei, E-mail: yyfgoat@nuaa.edu.cn [College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Li, Liang [College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Chen, Bo; Tian, Hui [Xi’an Aircraft Industrial (Group) Co. Ltd., Xi’an 710000 (China)

2015-09-17

The cold-compression stress relief process has been used to reduce the quench-induced stresses in high-strength aerospace aluminum alloy forgings. However, this method does not completely relieve the stress. Longitudinal residual stresses in 7050-T7452 aluminum alloy forging were measured with contour method. The measuring procedure of the contour method including specimen cutting under clamps with a wire electrical discharge machine, contour measurement of the cut surface with a laser scanner, careful data processing and elastic finite element analysis was introduced in detail. In addition, multiple cuts were used to map cross sectional stress at different cut surfaces. Finally, the longitudinal residual stress throughout the cut plane was mapped, and through thickness longitudinal stress profiles were also analyzed. Investigated results suggest that spatial variation of stress distribution can be attributed to the non-uniform plastic deformation of the cold-compression stress relief process. The overall reduction of peak stress magnitudes is approximately 43–79%.

Assessment of residual stress of 7050-T7452 aluminum alloy forging using the contour method

International Nuclear Information System (INIS)

Zhang, Zheng; Yang, Yinfei; Li, Liang; Chen, Bo; Tian, Hui

2015-01-01

The cold-compression stress relief process has been used to reduce the quench-induced stresses in high-strength aerospace aluminum alloy forgings. However, this method does not completely relieve the stress. Longitudinal residual stresses in 7050-T7452 aluminum alloy forging were measured with contour method. The measuring procedure of the contour method including specimen cutting under clamps with a wire electrical discharge machine, contour measurement of the cut surface with a laser scanner, careful data processing and elastic finite element analysis was introduced in detail. In addition, multiple cuts were used to map cross sectional stress at different cut surfaces. Finally, the longitudinal residual stress throughout the cut plane was mapped, and through thickness longitudinal stress profiles were also analyzed. Investigated results suggest that spatial variation of stress distribution can be attributed to the non-uniform plastic deformation of the cold-compression stress relief process. The overall reduction of peak stress magnitudes is approximately 43–79%

Forging Long Shafts On Disks

Science.gov (United States)

Tilghman, Chris; Askey, William; Hopkins, Steven

1989-01-01

Isothermal-forging apparatus produces long shafts integral with disks. Equipment based on modification of conventional isothermal-forging equipment, required stroke cut by more than half. Enables forging of shafts as long as 48 in. (122 cm) on typical modified conventional forging press, otherwise limited to making shafts no longer than 18 in. (46cm). Removable punch, in which forged material cools after plastic deformation, essential novel feature of forging apparatus. Technology used to improve such products as components of gas turbines and turbopumps and of other shaft/disk parts for powerplants, drive trains, or static structures.

Precision forging technology for aluminum alloy

Science.gov (United States)

Deng, Lei; Wang, Xinyun; Jin, Junsong; Xia, Juchen

2018-03-01

Aluminum alloy is a preferred metal material for lightweight part manufacturing in aerospace, automobile, and weapon industries due to its good physical properties, such as low density, high specific strength, and good corrosion resistance. However, during forging processes, underfilling, folding, broken streamline, crack, coarse grain, and other macro- or microdefects are easily generated because of the deformation characteristics of aluminum alloys, including narrow forgeable temperature region, fast heat dissipation to dies, strong adhesion, high strain rate sensitivity, and large flow resistance. Thus, it is seriously restricted for the forged part to obtain precision shape and enhanced property. In this paper, progresses in precision forging technologies of aluminum alloy parts were reviewed. Several advanced precision forging technologies have been developed, including closed die forging, isothermal die forging, local loading forging, metal flow forging with relief cavity, auxiliary force or vibration loading, casting-forging hybrid forming, and stamping-forging hybrid forming. High-precision aluminum alloy parts can be realized by controlling the forging processes and parameters or combining precision forging technologies with other forming technologies. The development of these technologies is beneficial to promote the application of aluminum alloys in manufacturing of lightweight parts.

Optimum design of forging process parameters and preform shape under uncertainties

International Nuclear Information System (INIS)

Repalle, Jalaja; Grandhi, Ramana V.

2004-01-01

Forging is a highly complex non-linear process that is vulnerable to various uncertainties, such as variations in billet geometry, die temperature, material properties, workpiece and forging equipment positional errors and process parameters. A combination of these uncertainties could induce heavy manufacturing losses through premature die failure, final part geometric distortion and production risk. Identifying the sources of uncertainties, quantifying and controlling them will reduce risk in the manufacturing environment, which will minimize the overall cost of production. In this paper, various uncertainties that affect forging tool life and preform design are identified, and their cumulative effect on the forging process is evaluated. Since the forging process simulation is computationally intensive, the response surface approach is used to reduce time by establishing a relationship between the system performance and the critical process design parameters. Variability in system performance due to randomness in the parameters is computed by applying Monte Carlo Simulations (MCS) on generated Response Surface Models (RSM). Finally, a Robust Methodology is developed to optimize forging process parameters and preform shape. The developed method is demonstrated by applying it to an axisymmetric H-cross section disk forging to improve the product quality and robustness

Cutting work in thick section cryomicrotomy.

Science.gov (United States)

Saubermann, A J; Riley, W D; Beeuwkes, R

1977-09-01

The forces during cryosectioning were measured using miniature strain gauges attached to a load cell fitted to the drive arm of the Porter-Blum MT-2 cryomicrotome. Work was calculated and the data normalized to a standard (1 mm X 1 mm X 0.5 micrometer) section. Thermal energy generated was also calculated. Five parameters were studied: cutting angle, thickness, temperature, hardness, and block shape. Force patterns could be divided into three major groups thought to represent cutting (Type I), large fracture planes greater than 10 micrometer in length (Type II), and small fracture planes less than 10 micrometer in length (Type III). Type I and Type II produced satisfactory sections. Work in cutting ranged from an average of 78.4 muJ to 568.8 muJ. Cutting angle and temperature had the greatest effect on sectioning. Heat generated would be sufficient to cause through-section melting for 0.5 micrometer thick sections assuming the worst possible case, namely that all heat went into the section without loss. Presence of a Type II pattern (large fracture pattern) is thought to be presumptive evidence against thawing.

Properties of powder metallurgy steel forgings

International Nuclear Information System (INIS)

Crowson, A.; Anderson, F.E.

1977-01-01

The effects of processing variables on the mechanical properties of heat-treated powder metallurgy (P/M) steel forgings were determined. Prealloyed 4600 steel powder blended with graphite to yield 4640 was compacted into preforms and hot forged in a warm, closed die. Variables studied were preform density, method of lubrication, preform sintering (time, temperature and atmosphere), forging pressure (20 and 40 tsi) and temperature (1850 0 F, 2000 0 F and 2200 0 F), and forging ratio (0.75 and 0.95). Relationships between interconnected porosity and total porosity for the various preform densities were determined. High density compacts required higher sintering temperatures due to the restricted mobility of the reducing gases in the pores. Die wall lubrication was comparable to admixed lubrication, and it simplified powder mixing and preform sintering operations. Forgings with densities from 99 to 99.8 percent of theoretical density were attained with a forging pressure of 20 to 40 tsi and preform temperatures of 2000 0 F and above. At forging conditions which resulted in forgings with acceptable mechanical properties, complete die fill was accomplished at a forging ratio of 0.95, whereas incomplete die fill resulted at a forging ratio of 0.75. The response of P/M forgings to heat treatment was comparable to that for wrought materials, and the resultant tensile and yield strengths were equivalent to the strength values described for wrought 4640 steel in AMS specification 6317B. In addition, ductility and impact properties of P/M forgings with near theoretical density (99.5+ percent) were comparable to bar stock forgings

[A method of temperature measurement for hot forging with surface oxide based on infrared spectroscopy].

Science.gov (United States)

Zhang, Yu-cun; Qi, Yan-de; Fu, Xian-bin

2012-05-01

High temperature large forging is covered with a thick oxide during forging. It leads to a big measurement data error. In this paper, a method of measuring temperature based on infrared spectroscopy is presented. It can effectively eliminate the influence of surface oxide on the measurement of temperature. The method can measure the surface temperature and emissivity of the oxide directly using the infrared spectrum. The infrared spectrum is radiated from surface oxide of forging. Then it can derive the real temperature of hot forging covered with the oxide using the heat exchange equation. In order to greatly restrain interference spectroscopy through included in the received infrared radiation spectrum, three interference filter system was proposed, and a group of optimal gap parameter values using spectral simulation were obtained. The precision of temperature measurement was improved. The experimental results show that the method can accurately measure the surface temperature of high temperature forging covered with oxide. It meets the requirements of measurement accuracy, and the temperature measurement method is feasible according to the experiment result.

Economical Fabrication of Thick-Section Ceramic Matrix Composites

Science.gov (United States)

Babcock, Jason; Ramachandran, Gautham; Williams, Brian; Benander, Robert

2010-01-01

A method was developed for producing thick-section [>2 in. (approx.5 cm)], continuous fiber-reinforced ceramic matrix composites (CMCs). Ultramet-modified fiber interface coating and melt infiltration processing, developed previously for thin-section components, were used for the fabrication of CMCs that were an order of magnitude greater in thickness [up to 2.5 in. (approx.6.4 cm)]. Melt processing first involves infiltration of a fiber preform with the desired interface coating, and then with carbon to partially densify the preform. A molten refractory metal is then infiltrated and reacts with the excess carbon to form the carbide matrix without damaging the fiber reinforcement. Infiltration occurs from the inside out as the molten metal fills virtually all the available void space. Densification to thick-section components required modification of the conventional process conditions, and the means by which the large amount of molten metal is introduced into the fiber preform. Modification of the low-temperature, ultraviolet-enhanced chemical vapor deposition process used to apply interface coatings to the fiber preform was also required to accommodate the high preform thickness. The thick-section CMC processing developed in this work proved to be invaluable for component development, fabrication, and testing in two complementary efforts. In a project for the Army, involving SiC/SiC blisk development, nominally 0.8 in. thick x 8 in. diameter (approx. 2 cm thick x 20 cm diameter) components were successfully infiltrated. Blisk hubs were machined using diamond-embedded cutting tools and successfully spin-tested. Good ply uniformity and extremely low residual porosity (41 ksi (approx. 283 MPa) flexural strength.

Forging evaluaion of 304L stainless steel

International Nuclear Information System (INIS)

Packard, C.L.; Edstrom, C.M.

1979-01-01

The objective of this project was to evaluate and characterize the effects of various forging parameters on the metallographic structure and mechanical properties of 304L stainless steel forgings. Upset and die forgings were produced by hammer and Dynapak forging with forging temperatures ranging from 760 to 1145 0 C, upset reductions ranging from 20 to 60%, and annealing times ranging from 0 to 25 minutes at 843 0 C. The carbide precipitation behavior observed was found to be a function of forging temperature and annealing time. Higher forging temperatures were beneficial in avoiding continuous carbide precipitation and annealing at 843 0 C promoted increased carbide precipitation. The yield strength of the unannealed forgings decreased with increasing forging temperature and, with the exception of the 1145 0 C upset forgings, was significantly lowered by annealing

Modelling of defects in ingot forging

DEFF Research Database (Denmark)

Christiansen, Peter

The present report presents an investigation of the ingot forging process with special emphasis on modelling the influence of die geometry on the soundness of the ingot after hot forging. An investigation on how to model damage is also performed. The influence of the lower die angle is quantified...... angle of 130o-140o giving rise to the largest centreline porosity closure regardless of material hardening behaviour applied. Friction was found only to have minor influence on the optimum. Multi stroke forging operations have also been modelled since the ingot forging process consists of many forging...... damage. It is found that when evaluating damage only by relative density; feed size and lower die angle does not influence whether the hot forging process is successful or not. This is in disagreement with the general understanding of the ingot forging process. When evaluating ductile damage...

Forging Industry Leadtimes: An Analysis of Causes for and Solutions to Long Leadtimes for Aerospace Forgings

Science.gov (United States)

1986-09-01

Pamplet . Forging Industry Association, Cleveland-MT, uncatea. 20. Forging Industry Association, and American Society for Metals. Forging Handbook, edited... Pamplet . The Harris-Thomas Drop Forge Compnyayto--n R, undated. 43. Theeck, Michael F., TECH MOD Program Mana.er. Personal interview. Industrial Base... Brochure . Worcester MA, 3, . 125 "’ VITA Captain Stephen F. O’Neill was born on 19 June 1957 in Pittsfield, Massachusetts. He graduated from high school

Influence of the Constitutive Flow Law in FEM Simulation of the Radial Forging Process

Directory of Open Access Journals (Sweden)

Olivier Pantalé

2013-01-01

Full Text Available Radial forging is a widely used forming process for manufacturing hollow products in transport industry. As the deformation of the workpiece, during the process, is a consequence of a large number of high-speed strokes, the Johnson-Cook constitutive law (taking into account the strain rate seems to be well adapted for representing the material behavior even if the process is performed under cold conditions. But numerous contributions concerning radial forging analysis, in the literature, are based on a simple elastic-plastic formulation. As far as we know, this assumption has yet not been validated for the radial forging process. Because of the importance of the flow law in the effectiveness of the model, our purpose in this paper is to analyze the influence of the use of an elastic-viscoplastic formulation instead of an elastic-plastic one for modeling the cold radial forging process. In this paper we have selected two different laws for the simulations: the Johnson-Cook and the Ludwik ones, and we have compared the results in terms of forging force, product's thickness, strains, stresses, and CPU time. For the presented study we use an AISI 4140 steel, and we denote a fairly good agreement between the results obtained using both laws.

The influence of main parameters of the process of forging on the initial quality of forging for steel 35HM

International Nuclear Information System (INIS)

Banaszek, G.; Dyja, H.; Berski, S.

2001-01-01

The article discuss the effect of the main forging parameters and the selection of tools on improving the internal quality of forgings and closing up discontinuities of metallurgical origin during forging. As a result of investigations, the optimal values of the main technological parameters of forging have been determined and the application of an appropriate group of tools have been proposed for the flat die forging of forgings. (author)

Microstructure Evolution and Surface Cracking Behavior of Superheavy Forgings during Hot Forging

Directory of Open Access Journals (Sweden)

Zhenhua Wang

2018-01-01

Full Text Available In recent years, superheavy forgings that are manufactured from 600 t grade ingots have been applied in the latest generation of nuclear power plants to provide good safety. However, component production is pushing the limits of the current free-forging industry. Large initial grain sizes and a low strain rate are the main factors that contribute to the deformation of superheavy forgings during forging. In this study, 18Mn18Cr0.6N steel with a coarse grain structure was selected as a model material. Hot compression and hot tension tests were conducted at a strain rate of 10−4·s−1. The essential nucleation mechanism of the dynamic recrystallization involved low-angle grain boundary formation and subgrain rotation, which was independent of the original high-angle grain boundary bulging and the presence of twins. Twins were formed during the growth of dynamic recrystallization grains. The grain refinement was not obvious at 1150°C. A lowering of the deformation temperature to 1050°C resulted in a fine grain structure; however, the stress increased significantly. Crack-propagation paths included high-angle grain boundaries, twin boundaries, and the insides of grains, in that order. For superheavy forging, the ingot should have a larger height and a smaller diameter.

Optimal reconstructed section thickness for the detection of liver lesions with multidetector CT

International Nuclear Information System (INIS)

Soo, G.; Lau, K.K.; Yik, T.; Kutschera, P.

2010-01-01

Aim: To evaluate the impact of different reconstructed section thicknesses on liver lesion detection using multidetector computed tomography (CT). Methods: Fifty-three patients were examined using a 16-section CT machine with axial reconstructions provided at 2.5, 5, 7.5, and 10 mm section thicknesses. Images of different reconstructed section thicknesses from different patients were presented in random order to three independent, blinded radiologists for review at multiple sessions. All images were then reviewed by three radiologists in a common session. Consensus was reached following review of the previous interpretation results and results of follow-up imaging regarding the number of true liver lesions (n = 101) for comparison. Results: Mean detection rates were as follows: 93/101 lesions detected with the 2.5 mm section thickness, 98/101 lesions detected at the 5 mm section thickness, 78/101 lesions detected at the 7.5 mm section thickness, and 54/101 lesions detected at the 10 mm section thickness. Lesions missed at the 2.5 mm section thickness were due to masking by image noise. There was particular difficulty detecting subcapsular lesions and lesions adjacent to fissures or the gall bladder at the 7.5 mm and 10 mm section thicknesses. Conclusion: The optimal reconstructed section thickness for lesion detection in the liver was 5 mm.

Microstructural and mechanical evolutions during the forging step of the COBAPRESS, a casting/forging process

Science.gov (United States)

Perrier, Frédéric; Desrayaud, Christophe; Bouvier, Véronique

Aluminum casting/forging processes are used to produce parts for the automotive industry. In this study, we examined the influence of the forging step on the microstructure and the mechanical properties of an A356 aluminum alloy modified with strontium. Firstly, a design of samples which allows us to test mechanically the alloy before and after forging was created. A finite element analysis with the ABAQUS software predicts a maximum of strain in the core of the specimens. Observations with the EBSD technique confirm a more intense sub-structuration of the dendrite cells in this zone. Yield strength, ultimate tensile strength, elongation and fatigue lives were then improved for the casting/forging samples compared to the only cast specimens. The closure of the porosities and the improvement of the surface quality during the forging step enhance also the fatigue resistance of the samples.

New Trends in Forging Technologies

Science.gov (United States)

Behrens, B.-A.; Hagen, T.; Knigge, J.; Elgaly, I.; Hadifi, T.; Bouguecha, A.

2011-05-01

Limited natural resources increase the demand on highly efficient machinery and transportation means. New energy-saving mobility concepts call for design optimisation through downsizing of components and choice of corrosion resistant materials possessing high strength to density ratios. Component downsizing can be performed either by constructive structural optimisation or by substituting heavy materials with lighter high-strength ones. In this context, forging plays an important role in manufacturing load-optimised structural components. At the Institute of Metal Forming and Metal-Forming Machines (IFUM) various innovative forging technologies have been developed. With regard to structural optimisation, different strategies for localised reinforcement of components were investigated. Locally induced strain hardening by means of cold forging under a superimposed hydrostatic pressure could be realised. In addition, controlled martensitic zones could be created through forming induced phase conversion in metastable austenitic steels. Other research focused on the replacement of heavy steel parts with high-strength nonferrous alloys or hybrid material compounds. Several forging processes of magnesium, aluminium and titanium alloys for different aeronautical and automotive applications were developed. The whole process chain from material characterisation via simulation-based process design to the production of the parts has been considered. The feasibility of forging complex shaped geometries using these alloys was confirmed. In spite of the difficulties encountered due to machine noise and high temperature, acoustic emission (AE) technique has been successfully applied for online monitoring of forging defects. New AE analysis algorithm has been developed, so that different signal patterns due to various events such as product/die cracking or die wear could be detected and classified. Further, the feasibility of the mentioned forging technologies was proven by means

The effects of composition and thermal path on hot ductility of forging steels

Science.gov (United States)

Connolly, Brendan M.

This work examines the effects of composition and thermal path on the hot ductility of several forging steels with varied aluminum and nitrogen content. The primary mechanisms and controlling factors related to hot ductility are identified with a focus on the role of precipitates and segregation. The unique thermal paths and solidification structures of large cross-section forging ingots are discussed. Hot ductility testing is performed in a manner that approximates industrial conditions experienced by large cross-section forging ingots. A computer model for precipitation of aluminum nitride and vanadium nitride in austenite is presented. Industrial material is examined for comparison to experimental findings. It is found that increased aluminum and nitrogen content coarsens the as-solidified structure. The combined effects of microsegregation and uphill diffusion during deformation allow for carbide precipitation at prior austenite grain boundaries which reduces the hot ductility.

Numerical simulation and experimental verification of microstructure evolution in large forged pipe used for AP1000 nuclear power plants

International Nuclear Information System (INIS)

Wang, Shenglong; Yang, Bin; Zhang, Mingxian; Wu, Huanchun; Peng, Jintao; Gao, Yang

2016-01-01

Highlights: • Establish systematically the database of 316LN stainless steel for Deform-3D. • Simulate the microstructure evolution during forging of AP1000 primary coolant pipe. • Carry out full-scale forging experiment for verification in engineering practice. • Get desirable grain size in simulation and experiment. • The variation trends of grain sizes in simulation and experiment are consistent. - Abstract: AP1000 primary coolant pipe is a large special-shaped forged pipe made of 316LN stainless steel. Due to the non-uniform temperature and deformation during its forging, coarse and fine grains usually coexist in the forged pipe, resulting in the heterogeneous microstructure and anisotropic performance. To investigate the microstructure evolution during the entire forging process, in the present research, the database of the 316LN stainless steel was established and a numerical simulation was performed. The results indicate that the middle body section of the forged pipe has an extremely uniform average grain size with the value smaller than 30 μm. The grain sizes in the ends of body sections were ranged from 30 μm to 60 μm. Boss sections have relatively homogeneous microstructure with the average grain size 30 μm to 44 μm. Furthermore, a full-scale hot forging was carried out for verification. Comparison of theoretical and experimental results showed good agreement and hence demonstrated the capabilities of the numerical simulation presented here. It is noteworthy that all grains in the workpiece were confirmed less than 180 μm, which meets the designer’s demands.

Wear Analysis of Die Inserts in the Hot Forging Process of a Forked Type Forging Using Reverse Scanning Techniques

Directory of Open Access Journals (Sweden)

Łukasz Dworzak

2017-12-01

Full Text Available This article presents a wear analysis of die inserts used in the hot forging process of a forked forging (yoke, an element applied in steering systems of passenger vehicles. Studies involved the application of an original reverse scanning method intended for rapid and reliable wear analysis of forging tools (with complicated shape affording easy assessment without the need to dismount tools from the forging unit. The developed method involves analysis of progressive wear of forging tools based on measurements (scanning of forgings periodically collected from the process and constitutes a useful tool for measurement and testing. As the authors’ earlier works have demonstrated, the proposed new approach to analysis of tool wear with the application of reverse 3D scanning has proven successful in multiple instances in the case of axially symmetrical objects. The presented results of studies indicate that it is possible to utilize the expanded method to analyze the lifetime of forging tools, including tools with complex geometry. Application of the reverse scanning method allows for continuous and practical monitoring of the condition of forging tools over the course of the forging process and should have a positive impact on improving production output and reducing production costs.

Fabrication and mechanical test data for the four 6-inch-thick intermediate test vessels made from steel plate for the Heavy Section Steel Program

International Nuclear Information System (INIS)

Childress, C.E.

1976-01-01

The HSST Program has among its goals the objective of demonstrating the capability to predict safe behavior of thick-walled pressure vessels containing flaws of known dimensions under frangible, transitional, and tough loading regimes. To accomplish these objectives the program is conducting a series of tests involving 6-in.-thick pressure vessels which will serve as test specimens for assisting in the characterization of failure under these loading conditions. Among the vessels a number of parameters, such as weld type, weld location, flaw size and shape, and test temperature and pressure, will be selectively varied to show that a rationale exists for dealing with the varied stress and metallurgical states which normally exist in commercial nuclear reactor vessels. Each vessel will serve as a go, no-go determination of critical flaw size for a specific set of test parameters. Item 4 of the previous issues in this series covers the fabrication details of the first six 6-in.-thick test vessels, which were fabricated from ASTM A-508 Cl 2 forging materials. This report covers the fabrication details of four additional 6-in.-thick intermediate test vessels having shell courses fabricated from ASTM A-533 Gr B Cl 1 plate. The remaining components were made from forgings. Essentially this report is a continuation of ORNL-TM-4351; it describes the manufacturing details of the individual parts and their ultimate assembly into finished vessels. Details concerning chemical composition and mechanical and nondestructive test data are presented

Distribution of Microstructure and Vickers Hardness in Spur Bevel Gear Formed by Cold Rotary Forging

Directory of Open Access Journals (Sweden)

Wuhao Zhuang

2014-11-01

Full Text Available Cold rotary forging is a novel metal forming technology which is widely used to produce the high performance gears. Investigating the microstructure and mechanical property of cold rotary forged gears has a great significance in improving their service performance. In this study, the grain morphology in different regions of the spur bevel gear which is processed by cold rotary forging is presented. And the distribution regulars of the grain deformation and Vickers hardness in the transverse and axial sections of the gear tooth are studied experimentally. A three-dimensional rigid-plastic FE model is developed to simulate the cold rotary forging process of a spur bevel gear under the DEFORM-3D software environment. The variation of effective strain in the spur bevel gear has been investigated so as to explain the distribution regulars of the microstructure and Vickers hardness. The results of this research thoroughly reveal the inhomogeneous deformation mechanisms in cold rotary forging of spur bevel gears and provide valuable guidelines for improving the performance of cold rotary forged spur bevel gears.

Weldability and mechanical property characterization of weld clad alloy 800H tubesheet forging

International Nuclear Information System (INIS)

King, J.F.; McCoy, H.E.

1984-09-01

The weldability of an alloy 800H forging that simulates a steam generator tubesheet is studied. Weldability was of concern because a wide range of microstructures was present in this forging. The top and portions of the bottom were weld clad with ERNiC-3 weld metal to a thickness of 19 mm similar to that anticipated for HTGR steam generators. Examinations of the clad fusion line in various regions revealed no weldability problems except possibly on the bottom portion, which contained large grains and some as-cast structure. A few microfissures were evident in this region, but no excessive hot cracking tendency was observed. The tensile properties in all areas of the clad forging were reasonable and not influenced greatly by the microstructure. The elevated-temperature tests showed strong tendency for fracture in the heat-affected zone of the alloy 800H. Creep failure at 649 0 C consistently occurred in the heat-affected zone of the alloy 800H, but the creep strength exceeded the expected values for alloy 800H

Reparation of damaged forging dies

Directory of Open Access Journals (Sweden)

Vukić Lazić

2015-03-01

Full Text Available The forging dies are in exploitation exposed to elevated temperatures and variable impact loads, both compressive and shear. Steels for manufacturing of these tools must endure those loads while maintaining mechanical properties and being resistant to wear and thermal fatigue. For those reasons, the alloyed steels are used for making the forging dies, though they have less weldability, because alloying increases proneness to hardening. Any reparatory hard facing (HF of the damaged dies would require the specially adjusted technology to the particular piece. In this paper reparatory hard facing of dies used for forging pieces in the automobile industry is considered. Prior to reparatory hard facing of the real tools, numerous experimental hard facings on models were performed. All the model hard facings were done on the same steels which were used for production of the real forging dies. To define the optimal hard facing technology one needs to derive the optimal combination of the adequate heat treatment(s, to select the proper filler metals and the welding procedure. The established optimal HF technology was applied to real forging dies whose service life was further monitored in conditions of exploitation

Forging of Advanced Disk Alloy LSHR

Science.gov (United States)

Gabb, Timothy P.; Gayda, John; Falsey, John

2005-01-01

The powder metallurgy disk alloy LSHR was designed with a relatively low gamma precipitate solvus temperature and high refractory element content to allow versatile heat treatment processing combined with high tensile, creep and fatigue properties. Grain size can be chiefly controlled through proper selection of solution heat treatment temperatures relative to the gamma precipitate solvus temperature. However, forging process conditions can also significantly influence solution heat treatment-grain size response. Therefore, it is necessary to understand the relationships between forging process conditions and the eventual grain size of solution heat treated material. A series of forging experiments were performed with subsequent subsolvus and supersolvus heat treatments, in search of suitable forging conditions for producing uniform fine grain and coarse grain microstructures. Subsolvus, supersolvus, and combined subsolvus plus supersolvus heat treatments were then applied. Forging and subsequent heat treatment conditions were identified allowing uniform fine and coarse grain microstructures.

Role of forgings in powder metallurgy industry

International Nuclear Information System (INIS)

Hayes, A.F.; DeRidder, A.J.

1975-01-01

Forging of powder metallurgy materials is discussed. Information and data are included on forging powder metallurgy W, Mo, In 100, Rene 95, Astroloy, Be, and Ti. It is noted that the combination of powder metallurgy and forging work provides the best product from standpoints of reproducibility, freedom from segregation, low scrap rate, and uniform mechanical properties. Experience is being used to develop contour forging from hot isostatic pressed billets or preforms. The quality of this product is under evaluation. Results show steady improvement and it is anticipated that continued effort will soon produce a reliable, less costly product. Forging can continue to be relied upon to correct subtle defects present in powder metallurgy material

Forging loads, deformation modes and fracture in axi-symmetrric closed die cold forging of sintered aluminium powder compacts

International Nuclear Information System (INIS)

Butt, M.A.; Ali, L.

2003-01-01

An experimental investigation into closed-die cold forging of sintered aluminium powder rod- shaped compacts was carried out. Axi-symmetric components were forged from sintered powder preforms with different initial diameter to height ratios. Different compaction pressures, sintering and lubrication conditions were used as variables during the investigations. Detailed observations were made on green/sintered density, compaction defects, forging loads, deformation modes and on the onset of fracture during progressive forging of sintered powder compacts. Experimental results obtained during the investigations have been presented and discussed in detail. (author)

Development of forging technology for PWR primary piping

International Nuclear Information System (INIS)

Morin, F.; Badeau, J.P.; Lambs, R.

1996-01-01

The purpose of this presentation is to give information on the changes in the design and manufacture of Primary Piping for electronuclear boilers of the Pressurized Water Reactor type (PWR) which has resulted in the making of one-piece forged lines including stub pipes and arcs. The optimization of these items is aimed at improving the life of the new power stations as well as guaranteeing their safety, while reducing inspection and maintenance requirements in service. The demonstration of the manufacturing feasibility has just been completed. It has taken material form in the installation, on the CIVAUX 1 section, of the first one-piece cold leg in the world. It will shortly be followed by the installation on the CIVAUX 2 section of a complete loop of bent forged pipes. Therefore, this new know-how is going to be incorporated in the French Rules (RCC-M) and can be directly taken into consideration both in the next work to be done and in the design and definition of a future nuclear reactor

Recent technological developments in forging; Recentes avancos tecnologicos no forjamento

Energy Technology Data Exchange (ETDEWEB)

Schaeffer, Lirio [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Programa de Pos-graduacao em Engenharia Metalurgica e dos Materiais

1987-12-31

Recent advances in the area of open and closed die forging are summarized and discussed. The use of computer and alternatives such as incremental forging, sinter forging, liquid forging and precision forging are the main items reviewed 11 refs., 10 figs.

Heavy forgings for reactor pressure vessels

International Nuclear Information System (INIS)

Cerjak, H.; Papouschek, F.

1979-01-01

The importance of forgings for an optimal design of nuclear components is described. Problems concerning the correlation of requirements, material behavior, fabrication and testing of forgings are discussed. (orig.) [de

High-Temperature Oxidation Behavior and Kinetics of Forged 12Cr-MoVW Steel

Directory of Open Access Journals (Sweden)

Kim Yong Hwan

2017-06-01

Full Text Available The oxidation kinetics of forged 12Cr-MoVW steel was investigated in an air (N2+O2 atmosphere at 873-1073 K (Δ50 K using thermogravimetric analysis. The oxidized samples were characterized using X-ray diffraction, and the surface and cross-sectional morphologies were examined using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. The forged 12Cr-MoVW steel samples exhibited parabolic behavior and a low oxidation rate compared with their as-cast counterparts. A protective oxide layer was uniformly formed at relatively low temperature (≤973 K for the forged samples, which thus exhibited better oxidation resistance than the as-cast ones. These oxides are considered solid-solution compounds such as (Fe, Cr2O3.

Manufacturing of ultra-large diameter 20 MnMoNi 5 5 steel forgings for reactor pressure vessels and their properties

International Nuclear Information System (INIS)

Onodera, S.; Kawaguchi, S.; Tsukada, H.; Moritani, H.; Suzuki, K.; Sato, I.

1985-01-01

As the structural material for RPV typical of increased dimensions, as set of ultra-large diameter steel forgings for a PHWR RPV is presented as outlined below. (1) Material designation: 20 MnMoNi 5 5 (similar to SA508, Cl.3) (2) Size of the forgings: flanges, 8.440 mm OD, a weight of 238 tons for shell flange; shells and torus, 7,920 mm OD, with large height, cover dome, 6,800 mm OD in chord and 460 mm thick; blank before formed to dome is ca. 8,000 mm OD. (3) Chemical composition: particular effort was made for minimizing the tramp elements as P, S, As, Sn, Sb, Cu. (4) Manufacturing, key points: steel making - combined refining and degassing in ladle; ingot making - largest size ingots, including 570 ton and 500 ton ingots; forging - special ''outside-the-press'' forging and forming techniques; heat treatment - prevention of H 2 flaking in normalizing and tempering and handling of the extra-large forgings at water quenching. (5) Metallurgical properties: sufficiently uniform carbon distributions in the forgings; a lowest possible content of hydrogen, non-metallic inclusions and oxygen. Mechanical properties: uniformity in tensile and toughness properties; flaws - only limited number of spots of UT indications under 2 mm EFG (EFS). (orig.)

Investigation of the Section Thickness Measurement in Tomosynthesis by Thin Metal Plate Edge Method.

Science.gov (United States)

Ikeno, Kaoru; Akita, Tsunemichi; Hanai, Kozo; Muramatsu, Yoshihisa

When performing tomosynthesis, the section thickness needs to be set depending on a radiographic part and its diagnostic purpose. However, the section thickness in tomosynthesis has not been clearly defined and its measurement method has not been established yet. In this study, we devised the alternative measurement method to diagnose the section thickness using an edge of thin metal plate, and compared with the simulation results, the wire and bead method reported in the previous papers. The tomographic image of the thin metal plate positioned on the table top inclining 30 degrees, which showed the edge spread function (ESF) of each tomographic height, was taken, and then the line spread function (LSF) was obtained by differentiating the ESF image. For the next, a profile curve was plotted by maximum values of LSF of each tomographic height, and a section thickness was calculated using the full width at half maximum (FWHM) of the profile curve. The edge method derived the section thickness close to the simulation results than the other methods. Further, the section thickness depends on the thickness of the metal plate and not the material. The thickness of the metal plate suitable for the evaluation of section thickness is 0.3 mm that is equivalent to pixel size of the flat panel detector (FPD). We conducted quantitative verification to establish the measurement method of the section thickness. The edge method is a useful technique as well as the wire and bead method for grasping basic characteristics of an imaging system.

31 CFR 370.40 - Can I be held accountable if my negligence contributes to a forged signature?

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Can I be held accountable if my negligence contributes to a forged signature? 370.40 Section 370.40 Money and Finance: Treasury Regulations... if my negligence contributes to a forged signature? (a) General. If your failure to exercise ordinary...

Section thickness-dependent tensile properties of squeeze cast magnesium alloy AM60

Directory of Open Access Journals (Sweden)

Xuezhi Zhang

2012-05-01

Full Text Available The development of alternative casting processes is essential for the high demand of light weight magnesium components to be used in the automotive industry, which often contain different section thicknesses. Squeeze casting with its inherent advantages has been approved for the capability of minimizing the gas porosity in magnesium alloys. For advanced engineering design of light magnesium automotive applications, it is critical to understand the effect of section thickness on mechanical properties of squeeze cast magnesium alloys. In this study, magnesium alloy AM60 with different section thicknesses of 6, 10 and 20 mm squeeze cast under an applied pressure of 30 MPa was investigated. The prepared squeeze cast AM60 specimens were tensile tested at room termperature. The results indicate that the mechanical properties including yield strength (YS, ultimate tensile strength (UTS and elongation (A decrease with an increase in section thickness of squeeze cast AM60. The microstructure analysis shows that the improvement in the tensile behavior of squeeze cast AM60 is primarily attributed to the low-gas porosity level and fine grain strucuture which result from the variation of cooling rate of different section thickness. The numerical simulation (Magmasoft? was employed to determine the solidification rates of each step, and the simulated results show that the solidification rate of the alloy decreases with an increase in the section thickness. The computed solidification rates support the experimental observation on grain structural development.

Effect of annealing, thickness ratio and bend angle on springback of AA6061-T6 with non-uniform thickness section

Directory of Open Access Journals (Sweden)

Adnan M.F.

2017-01-01

Full Text Available Non-uniform thickness section section is considered one of the most effective approaches to reduce automotive part weight. Reduction in term of mass and size result in less fuel consumption and greenhouse gases. Thickness is the most significant parameter to formability, therefore forming a section with non-uniform thickness becomes a great challenge. Improper process and incorrect decision may lead to severe defect and one of the main concerns is the springback. This study will focus on springback behaviour of non-uniform thickness AA6061 strip with complex profile using Taguchi Method. Profile projector (PC 3000 is used to measure the spring back and two-line technique is applied to measure angles (after loading between two lines. Three parameters (i.e. annealing temperature, thickness ratio and bend angle are studied, and results determine that the most significant parameter is bend angle, followed by thickness ratio, and then by the annealing temperature of the specimen during bending process.

Forging technology for large nuclear pressure vessel parts

International Nuclear Information System (INIS)

Kakimoto, Hideki; Ikegami, Tomonori

2014-01-01

The increasing output of nuclear power generation calls for larger vessels for next-generation nuclear power plants. A vessel with an increased diameter requires increased load for its forging, which can make it difficult to use a conventional solid die. In order to reduce the forging load, a rotary incremental forging method has been applied to hot forging. This method includes pressing and rotating a material in an incremental manner such that a target shape is obtained. This study aimed at improving the accuracy of numerical simulation for the rotary incremental forging to reduce the load when forging large vessels. This has enabled the temperature of the material and flow stress to be precisely predicted; an example of this is reported in the paper. Specifically, the heat transfer coefficient to be used for the numerical simulation had been determined experimentally from a small-scale hot-forging. The reduction of the flow stress associated with incremental forging, had been deduced from a compression test, and the value was applied to the numerical simulation. A preform was designed on the basis of the above simulation to perform a 1/1 size scale experiment. A precision of better than 5% has been confirmed for the shape prediction. (author)

Manufacturing of ultra-large diameter 20 MnMoNi 5 5 steel forgings for reactor pressure vessels and their properties

International Nuclear Information System (INIS)

Onodera, S.; Kawaguchi, S.; Tsukada, H.; Moritani, H.; Suzuki, K.; Sato, I.

1983-01-01

A set of component material for PHWR RPV, including the largest forgings ever manufacture so far such as flanges (8,440 mm O.D.), shells and torus (7,960 mm O.D.) and dome (6,800 mm dia. in chord, 460 mm thick), was presented in the outline of manufacturing and properties. Even with increased dimensions and weight than the current largest forgings, the manufacture and the qualities achieved were satisfactory. These results encourage us in further developing PWRs and PHWRs with increased capacity. (orig.)

Identification of forged Bank of England £20 banknotes using IR spectroscopy.

Science.gov (United States)

Sonnex, Emily; Almond, Matthew J; Baum, John V; Bond, John W

2014-01-24

Bank of England notes of £20 denomination have been studied using infrared spectroscopy in order to generate a method to identify forged notes. An aim of this work was to develop a non-destructive method so that a small, compact Fourier transform infrared spectrometer (FT-IR) instrument could be used by bank workers, police departments or others such as shop assistants to identify forged notes in a non-lab setting. The ease of use of the instrument is the key to this method, as well as the relatively low cost. The presence of a peak at 1400 cm(-1) arising from νasym (CO3(2-)) from the blank paper section of a forged note proved to be a successful indicator of the note's illegality for the notes that we studied. Moreover, differences between the spectra of forged and genuine £20 notes were observed in the ν(OH) (ca. 3500 cm(-1)), ν(C-H) (ca. 2900 cm(-1)) and ν(C=O) (ca. 1750 cm(-1)) regions of the IR spectrum recorded for the polymer film covering the holographic strip. In cases where these simple tests fail, we have shown how an infrared microscope can be used to further differentiate genuine and forged banknotes by producing infrared maps of selected areas of the note contrasting inks with background paper. Copyright © 2013 Elsevier B.V. All rights reserved.

Identification of forged Bank of England £20 banknotes using IR spectroscopy

Science.gov (United States)

Sonnex, Emily; Almond, Matthew J.; Baum, John V.; Bond, John W.

2014-01-01

Bank of England notes of £20 denomination have been studied using infrared spectroscopy in order to generate a method to identify forged notes. An aim of this work was to develop a non-destructive method so that a small, compact Fourier transform infrared spectrometer (FT-IR) instrument could be used by bank workers, police departments or others such as shop assistants to identify forged notes in a non-lab setting. The ease of use of the instrument is the key to this method, as well as the relatively low cost. The presence of a peak at 1400 cm-1 arising from νasym (CO32-) from the blank paper section of a forged note proved to be a successful indicator of the note's illegality for the notes that we studied. Moreover, differences between the spectra of forged and genuine £20 notes were observed in the ν(OH) (ca. 3500 cm-1), ν(Csbnd H) (ca. 2900 cm-1) and ν(Cdbnd O) (ca. 1750 cm-1) regions of the IR spectrum recorded for the polymer film covering the holographic strip. In cases where these simple tests fail, we have shown how an infrared microscope can be used to further differentiate genuine and forged banknotes by producing infrared maps of selected areas of the note contrasting inks with background paper.

International cooperation in cold forging technology

DEFF Research Database (Denmark)

Bay, Niels; Lange, K

1992-01-01

International cooperation in the field of cold forging technology started in 1961 by formation of the OECD Group of Experts on Metal Forming. In 1967 this group was transformed into the International Cold Forging Group, ICFG, an independent body which has now been operative for 25 years. Members...... of the ICFG are personally elected by the Plenary as experts within the field, often representing national groups within cold forging. The main work within the ICFG is carried out in its subgroups which are established by the Plenary to collect, compile and evaluate data and eventually also produce data...... by cooperative activities or by instigating national research. These subgroups have produced 9 data sheets and 7 guidelines on subjects such as materials, tool design and construction, calculation methods for cold forging tools, manufacture of slugs, lubrication aspects and small quantity production. Plenary...

Automated ultrasonic shop inspection of reactor pressure vessel forgings

International Nuclear Information System (INIS)

Farley, J.M.; Dikstra, B.J.; Hanstock, D.J.; Pople, C.H.

1986-01-01

Automated ultrasonic shop inspection utilizing a computer-controlled system is being applied to each of the forgings for the reactor pressure vessel of the proposed Sizewell B PWR power station. Procedures which utilize a combination of high sensitivity shear wave pulse echo, 0 degrees and 70 degrees angled longitudinal waves, tandem and through-thickness arrays have been developed to provide comprehensive coverage and an overall reliability of inspection comparable to the best achieved in UKAEA defect detection trials and in PISC II. This paper describes the ultrasonic techniques, the automated system (its design, commissioning and testing), validation and the progress of the inspections

Identification of Forged Bank of England 20 Gbp Banknotes Using IR Spectroscopy

Science.gov (United States)

Sonnex, Emily

2014-06-01

Bank of England notes of 20 GBP denomination have been studied using infrared spectroscopy in order to generate a method to identify forged notes. A principal aim of this work was to develop a method so that a small, compact ATR FTIR instrument could be used by bank workers, police departments or others such as shop assistants to identify forged notes in a non-lab setting. The ease of use of the instrument is the key to this method, as well as the relatively low cost. The presence of a peak at 1400 wn from the blank paper section of a forged note proved to be a successful indicator of the note's illegality for the notes that we studied. Moreover, differences between the spectra of forged and genuine 20 GBP notes were observed in the ν(OH) (ca. 3500 wn), ν(C-H) (ca. 2900 wn) and ν(C=O) (ca. 1750 wn) regions of the IR spectrum recorded for the polymer film covering the holographic strip. In cases where these simple tests fail, we have shown how an infrared microscope can be used to further differentiate genuine and forged banknotes by producing infrared maps of selected areas of the note contrasting inks with background paper. Further to this, with an announcement by the Bank of England to produce polymer banknotes in the future, the work has been extended using Australian polymer banknotes to show that the method would be transferable.

Anisotropy effects during dwell-fatigue caused by δ-phase orientation in forged Inconel 718

Energy Technology Data Exchange (ETDEWEB)

Saarimäki, Jonas, E-mail: jonas.saarimaki@liu.se [Division of Engineering Materials, Department of Management and Engineering, Linköping University, SE-58183 Linköping (Sweden); Colliander, Magnus Hörnqvist [Department of Applied Physics, Chalmers University of Technology, SE-41296 Göteborg (Sweden); GKN Aerospace Engine Systems, R& T Centre, SE-46181 Trollhättan (Sweden); Moverare, Johan J. [Division of Engineering Materials, Department of Management and Engineering, Linköping University, SE-58183 Linköping (Sweden)

2017-04-24

Inconel 718 is a commonly used superalloy for turbine discs in the gas turbine industry. Turbine discs are often subjected to dwell-fatigue as a result of long constant load cycles. The effect of anisotropy on dwell-fatigue cracking in forged turbine discs have not yet been thoroughly investigated. Crack propagation behaviour was characterised using compact tension (CT) samples cut in different orientations from a real turbine disc forging. Samples were also cut in two different thicknesses in order to investigate the influence of plane strain and plane stress condition on the crack propagation rates. The samples were subjected to dwell-fatigue tests at 550 °C with 90 s or 2160 s dwell-times at maximum load. Microstructure characterisation was done using scanning electron microscopy (SEM) techniques such as electron channelling contrast imaging (ECCI), electron backscatter diffraction (EBSD), and light optical microscopy (LOM). The forged alloy exhibits strong anisotropic behaviour caused by the non-random δ-phase orientation. When δ-phases were oriented perpendicular compared to parallel to the loading direction, the crack growth rates were approximately ten times faster. Crack growth occurred preferably in the interface between the γ-matrix and the δ-phase.

Press forging and optical properties of lithium fluoride

Science.gov (United States)

Ready, J. F.; Vora, H.

1980-07-01

Lithium fluoride is an important candidate material for windows on high power, short-pulse ultraviolet and visible lasers. Lithium fluoride crystals were press forged in one step over the temperature range 300 to 600 C to obtain fine grained polycrystalline material with improved mechanical properties. The deformation that can be given to a lithium fluoride crystal during forging is limited by the formation of internal cloudiness (veiling) with the deformation limit increasing with increasing forging temperature from about 40 percent at 400 C to 65 percent at 600 C. To suppress veiling, lithium fluoride crystals were forged in two steps over the temperature range 300 to 600 C, to total deformations of 69 to 76 percent, with intermediate annealing at 700 C. This technique yields a material which has lower scattering with more homogeneous microstructure than that obtained in one step forging. The results of characterization of various optical and mechanical properties of single crystal and forged lithium fluoride, including scattering, optical homogeneity, residual absorption, damage thresholds, environmental stability, and thresholds for microyield are described.

Press forging and optical properties of lithium fluoride

International Nuclear Information System (INIS)

Ready, J.F.; Vora, H.

1979-01-01

Lithium fluoride is an important candidate material for windows on high-power, short-pulse ultraviolet and visible lasers. Lithium fluoride crystals have been press forged in one step over the temperature range 300 to 600 0 c to obtain fine-grained polycrystalline material with improved mechanical properties. The deformation that can be given to a lithium fluoride crystal during forging is limited by the formation of internal cloudiness (veiling) with the deformation limit increasing with increasing forging temperature from about 40% at 400 0 C to 65% at 600 0 C. To suppress veiling, lithium fluoride crystals were forged in two steps over the temperature range 300 to 600 0 C, to total deformations of 69-76%, with intermediate annealing at 700 0 C. This technique yields a material which has lower scattering with more homogeneous microstructure than that obtained in one-step forging. The results of characterization of various optical and mechanical properties of single-crystal and forged lithium fluoride, including scattering, optical homogeneity, residual absorption, damage thresholds, environmental stability, and thresholds for microyield are described

Quality assurance for hammer forgings

International Nuclear Information System (INIS)

Potthast, E.

1984-01-01

The quality assurance program introduced by Arbed Saarstahl and laid down in a quality assurance manual is described. A particular attention is attached thereby both to quality practice proper and to a reliable flow of information amongst all the persons involved. The production and test sequence schedules of the hammer forging plant are illustrated by the example of a forged valve housing for nuclear power plants. These schedules specify not only the forging process in the individual production stages but also the workpiece contour after each working operation, the heat treatment, the furnace charging, and the inspection of finished parts. The formalization of the tests is designed both to promote the customer's trust towards the supplier and to prevent the formal operations involved from hindering further technical development. (orig.) [de

Co-Operative Training in the Sheffield Forging Industry

Science.gov (United States)

Duncan, R.

2008-01-01

Purpose: The purpose of this paper is to give details of an operation carried out in Sheffield to increase the recruitment of young men into the steel forging industry. Design/methodology/approach: The Sheffield Forges Co-operative Training Scheme was designed to encourage boys to enter the forging industry and to provide them with training and…

Sensitivity Analysis of Oxide Scale Influence on General Carbon Steels during Hot Forging

Directory of Open Access Journals (Sweden)

Bernd-Arno Behrens

2018-02-01

Full Text Available Increasing product requirements have made numerical simulation into a vital tool for the time- and cost-efficient process design. In order to accurately model hot forging processes with finite, element-based numerical methods, reliable models are required, which take the material behaviour, surface phenomena of die and workpiece, and machine kinematics into account. In hot forging processes, the surface properties are strongly affected by the growth of oxide scale, which influences the material flow, friction, and product quality of the finished component. The influence of different carbon contents on material behaviour is investigated by considering three different steel grades (C15, C45, and C60. For a general description of the material behaviour, an empirical approach is used to implement mathematical functions for expressing the relationship between flow stress and dominant influence variables like alloying elements, initial microstructure, and reheating mode. The deformation behaviour of oxide scale is separately modelled for each component with parameterized flow curves. The main focus of this work lies in the consideration of different materials as well as the calculation and assignment of their material properties in dependence on current process parameters by application of subroutines. The validated model is used to carry out the influence of various oxide scale parameters, like the scale thickness and the composition, on the hot forging process. Therefore, selected parameters have been varied within a numerical sensitivity analysis. The results show a strong influence of oxide scale on the friction behaviour as well as on the material flow during hot forging.

Effect of Forging Allowance Value on the Power Consumption of Machining Process

Directory of Open Access Journals (Sweden)

L. D. Mal'kova

2015-01-01

Full Text Available The paper aim is to develop and study possible energy-efficiency measures for machined forgings drawing on analysis of the impact of the allowance for machining and its scatter.The most sophisticated option to take into consideration the effect of the cut depth is the work-piece machining in which the forging allowance value results from the blank production.Research of power consumption was conducted for turning the cylindrical surface of 144 mm length and  1,5 33 0,5   diameter on forgings of the work-pieces "screw of steering control" made from steel 60PP. A radial dimension allowance at said cylindrical surface at six points of the five sections was sized to assess the allowance value dispersion. The size of the sample measurements at the control points was n = 600. Statistic processing has shown normal law of distribution and sample homogeneity.To analyze the results of experiments was calculated a range of allowances for this workpiece. Calculated minimum and maximum allowance per one side for rough lathing were, respectively, 0.905 mm and 1.905mm. It was found that 77% points under control lie in calculated range of allowance values. And there are no points out of the range on lesser side that proves a lack of rejects; but there are points out of the range on the bigger side, that will require additional costs for machining the specified surface, including the cost of electricity.There were three power consumption calculations based on factory- recommended duty: for processing the entire sample of forgings with an average allowance, for machining forgings allowances of which are within the recommended design range of allowance, and for processing the entire sample of forgings with a minimum value of allowance.It was found that elimination of allowance values which are outside the recommended range enables to reduce the power consumption, at least, by 6%, and the overall power consumption for processing the measured forgings

A material based approach to creating wear resistant surfaces for hot forging

Science.gov (United States)

Babu, Sailesh

Tools and dies used in metal forming are characterized by extremely high temperatures at the interface, high local pressures and large metal to metal sliding. These harsh conditions result in accelerated wear of tooling. Lubrication of tools, done to improve metal flow drastically quenches the surface layers of the tools and compounds the tool failure problem. This phenomenon becomes a serious issue when parts forged at complex and are expected to meet tight tolerances. Unpredictable and hence uncontrolled wear and degradation of tooling result in poor part quality and premature tool failure that result in high scrap, shop downtime, poor efficiency and high cost. The objective of this dissertation is to develop a computer-based methodology for analyzing the requirements hot forging tooling to resist wear and plastic deformation and wear and predicting life cycle of forge tooling. Development of such is a system is complicated by the fact that wear and degradation of tooling is influenced by not only the die material used but also numerous process controls like lubricant, dilution ratio, forging temperature, equipment used, tool geometries among others. Phenomenological models available u1 the literature give us a good thumb rule to selecting materials but do not provide a way to evaluate pits performance in field. Once a material is chosen, there are no proven approaches to create surfaces out of these materials. Coating approaches like PVD and CVD cannot generate thick coatings necessary to withstand the conditions under hot forging. Welding cannot generate complex surfaces without several secondary operations like heat treating and machining. If careful procedures are not followed, welds crack and seldom survive forging loads. There is a strong need for an approach to selectively, reliably and precisely deposit material of choice reliably on an existing surface which exhibit not only good tribological properties but also good adhesion to the substrate

Hot isostatically pressed (HIPed) thick-walled component for a pressurised water reactor (PWR) application

International Nuclear Information System (INIS)

Hookham, I.; Burdett, B.; Bridger, K.; Sulley, J.L.

2009-01-01

This paper presents the work conducted to justify and provide a quality assured HIPed thick-walled component for a PWR application; the component being designed and manufactured by Rolls-Royce. Rolls-Royce has previously published (ICAPP 08) its overall, staged approach to the introduction of powder HIPed components; starting with thin-walled, leak limited pressure boundaries, and culminating in the use of the powder HIPed process for thick walled components. This paper presents details specific to a thick walled pressure vessel component. Results are presented of non-destructive and destructive examinations of one of a batch of components. Mechanical testing and metallurgical examination results of sample material taken from different sections of the component are presented. A full range of test results is provided covering, as examples: tensile, Charpy impact and sensitization susceptibility. Differences in weldability between the HIPed and the previous forged form are also documented. (author)

Development of integral type forgings for steam generator of nuclear power plant

International Nuclear Information System (INIS)

Suzuki, Komei; Sato, Ikuo; Murai, Etsuo

1992-01-01

The use of integral type steel forgings for the construction of pressure vessel enhances the structural integrity of components and makes the fabrication of components and the execution of in-service inspection (ISI) easier than those fabrication from plate and casting materials. Such steel forgings have been realized for steam generator (SG) for nuclear power plant as follows : (1) Forged shell ring : change from welding fabrication of formed plates to forging ; (2) Forged conical shell ring : ditto ; (3) Forged head integral with nozzles (s) : (i) Primary head : change from casting to forging ; (ii) Secondary head : change from welding fabrication of formed plates to forging. These steel forgings have been realized by recent development in manufacturing technologies, such as steel making, forging processes and heat treatment which are vital to the quality of steel forgings. Some examples of recent typical high quality steel forgings developed by the Japan Steel Works, Ltd. (JSW) are introduced, and the main points of the manufacturing technique and the quality attained are also described. (author)

Repetitive forging (RF) using inclined punches as a new bulk severe plastic deformation method

Energy Technology Data Exchange (ETDEWEB)

Babaei, A. [Department of Mechanical Engineering, University College of Engineering, University of Tehran, Tehran 11155-4563 (Iran, Islamic Republic of); Faraji, G., E-mail: ghfaraji@ut.ac.ir [Department of Mechanical Engineering, University College of Engineering, University of Tehran, Tehran 11155-4563 (Iran, Islamic Republic of); Department of Engineering Design and Manufacture, University of Malaya, 50603 Kuala Lumpur (Malaysia); Mashhadi, M.M. [Department of Mechanical Engineering, University College of Engineering, University of Tehran, Tehran 11155-4563 (Iran, Islamic Republic of); Hamdi, M. [Department of Engineering Design and Manufacture, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2012-12-15

A new bulk severe plastic deformation method based on repetitive forging (RF) using inclined punches is proposed. This process consists of two half cycles. In the first half cycle, a square cross section deforms to parallelogram by forging with two inclined punches, and the parallelogram cross section is forged back to square using two flat punches in the second half cycle. This method was applied to commercially pure copper and significant grain refinement was achieved after four passes of RF. The results showed that significant improvement in the mechanical properties was obtained. Notable increase of yield and ultimate strengths corresponding to 358 MPa and 381 MPa after four passes of RF from the initial values of 121 MPa and 230.5 MPa is detectable. Microhardness increases to about 100 Hv after four passes of RF from the initial value of 53 Hv. Finite element (FE) results illustrate that RF is able to impose extremely high plastic strains to the materials. In the RF process, the processed samples have the same dimensions and geometry as those of the initial sample without any waste material and there is no need for back pressure.

Phased Array Ultrasonic Inspection of Titanium Forgings

International Nuclear Information System (INIS)

Howard, P.; Klaassen, R.; Kurkcu, N.; Barshinger, J.; Chalek, C.; Nieters, E.; Sun, Zongqi; Fromont, F. de

2007-01-01

Aerospace forging inspections typically use multiple, subsurface-focused sound beams in combination with digital C-scan image acquisition and display. Traditionally, forging inspections have been implemented using multiple single element, fixed focused transducers. Recent advances in phased array technology have made it possible to perform an equivalent inspection using a single phased array transducer. General Electric has developed a system to perform titanium forging inspection based on medical phased array technology and advanced image processing techniques. The components of that system and system performance for titanium inspection will be discussed

22 CFR 121.10 - Forgings, castings and machined bodies.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Forgings, castings and machined bodies. 121.10... STATES MUNITIONS LIST Enumeration of Articles § 121.10 Forgings, castings and machined bodies. Articles on the U.S. Munitions List include articles in a partially completed state (such as forgings...

Kinematics at the Main Mechanism of a Railbound Forging Manipulator

Directory of Open Access Journals (Sweden)

Florian Ion Tiberiu Petrescu

2015-09-01

Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Heavy payload forging manipulators are mainly characterized by large load output and large capacitive load input. The relationship between outputs and inputs will greatly influence the control and the reliability. Forging manipulators have become more prevalent in the industry today. They are used to manipulate objects to be forged. The most common forging manipulators are moving on a railway to have a greater precision and stability. They have been called the railbound forging manipulators. In this paper we analyze the general kinematics of the main mechanism from a such manipulator. Kinematic scheme shows a typical forging manipulator, with the basic motions in operation process: walking, motion of the tong and buffering. The lifting mechanism consists of several parts including linkages, hydraulic drives and motion pairs. The principle of type design from the viewpoints of the relationship between output characteristics and actuator inputs is discussed. An idea of establishing the incidence relationship between output characteristics and actuator inputs is proposed. These novel forging manipulators which satisfy certain functional requirements provide an effective help for the design of forging manipulators.

Study on the isothermal forging process of MB26 magnesium alloy adaptor

Directory of Open Access Journals (Sweden)

Xu Wenchen

2015-01-01

Full Text Available The isothermal forging process is an effective method to manufacture complex-shaped components of hard-to-work materials, such as magnesium alloys. This study investigates the isothermal forging process of an MB26 magnesium alloy adaptor with three branches. The results show that two-step forging process is appropriate to form the adaptor forging, which not only improves the filling quality but also reduces the forging load compared with one-step forging process. Moreover, the flow line is distributed along the contour of the complex-shaped adaptor forging.

Near-Net Forging Technology Demonstration Program

Science.gov (United States)

Hall, I. Keith

1996-01-01

Significant advantages in specific mechanical properties, when compared to conventional aluminum (Al) alloys, make aluminum-lithium (Al-Li) alloys attractive candidate materials for use in cryogenic propellant tanks and dry bay structures. However, the cost of Al-Li alloys is typically five times that of 2219 aluminum. If conventional fabrication processes are employed to fabricate launch vehicle structure, the material costs will restrict their utilization. In order to fully exploit the potential cost and performance benefits of Al-Li alloys, it is necessary that near-net manufacturing methods be developed to off-set or reduce raw material costs. Near-net forging is an advanced manufacturing method that uses elevated temperature metal movement (forging) to fabricate a single piece, near-net shape, structure. This process is termed 'near-net' because only a minimal amount of post-forge machining is required. The near-net forging process was developed to reduce the material scrap rate (buy-to-fly ratio) and fabrication costs associated with conventional manufacturing methods. The goal for the near-net forging process, when mature, is to achieve an overall cost reduction of approximately 50 percent compared with conventional manufacturing options for producing structures fabricated from Al-Li alloys. This NASA Marshall Space Flight Center (MSFC) sponsored program has been a part of a unique government / industry partnership, coordinated to develop and demonstrate near-net forging technology. The objective of this program was to demonstrate scale-up of the near-net forging process. This objective was successfully achieved by fabricating four integrally stiffened, 170- inch diameter by 20-inch tall, Al-Li alloy 2195, Y-ring adapters. Initially, two 2195 Al-Li ingots were converted and back extruded to produce four cylindrical blockers. Conventional ring rolling of the blockers was performed to produce ring preforms, which were then contour ring rolled to produce

27 CFR 447.22 - Forgings, castings, and machined bodies.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Forgings, castings, and... IMPLEMENTS OF WAR The U.S. Munitions Import List § 447.22 Forgings, castings, and machined bodies. Articles on the U.S. Munitions Import List include articles in a partially completed state (such as forgings...

The State of the Art in Cold Forging Lubrication

DEFF Research Database (Denmark)

Bay, Niels

1994-01-01

The manufature of components in steel, aluminium and copper alloys by cold forging production has increased ever since the 1950's. Typical processes are forward rod extrusion and backward can extrusion, upsetting, ironing, tube extrusion and radial extrusion. The tribological conditions in cold...... forging are extremely severe due to large surface expansion and normal pressure in the tool/workpiece interface combined with elevated tool temperatures. Except for the more simple cold forging operations successful production therefore requires advanced lubrication systems. The present paper gives...... a detailed description of the state of art for lubricant systems for cold forging of C-steels and low alloy steels as well as aluminium alloys including all the basic operations such as cleaning of the slugs, application of eventual conversion coating and lubrication. As regards cold forging of steel...

Instant forgedUI starter

CERN Document Server

Luiz, Joseandro

2013-01-01

Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks.The book is a Starter guide to learning ForgedUI. This book will start by unfolding the installation and creating a simple application using Titanium and ForgedUI, followed by taking you through the features to model an engaging UI and generate multi-platform code with Titanium, while covering the best design practice for Apple and Android application development. Last but not least, you will also come across the available resources where you can

An empirical model for friction in cold forging

DEFF Research Database (Denmark)

Bay, Niels; Eriksen, Morten; Tan, Xincai

2002-01-01

With a system of simulative tribology tests for cold forging the friction stress for aluminum, steel and stainless steel provided with typical lubricants for cold forging has been determined for varying normal pressure, surface expansion, sliding length and tool/work piece interface temperature...... of normal pressure and tool/work piece interface temperature. The model is verified by process testing measuring friction at varying reductions in cold forward rod extrusion. KEY WORDS: empirical friction model, cold forging, simulative friction tests....

Dorsiflexor muscle-group thickness in children with cerebral palsy: Relation to cross-sectional area

DEFF Research Database (Denmark)

Bandholm, Thomas; Magnusson, Peter; Jensen, Bente Rona

2009-01-01

If the thickness and cross-sectional area of the dorsiflexor muscle group are related in children with cerebral palsy, measurements of muscle thickness may be used to monitor changes in muscle size due to training or immobilisation in these patients. We assessed the validity and reliability.......001), and the reliability of the muscle-thickness measurements was high in the healthy subjects (ICC_{2.1} = 0.94, standard error of measurement = 0.04 cm). The dorsiflexor muscle-thickness was 22% less in the affected compared to the non-affected leg in children with hemiplegic cerebral palsy (P ..., the dorsiflexor cross-sectional area was 32% less in the affected compared to the non-affected leg (P = 0.002). Measurements of dorsiflexor muscle-thickness can be reliably obtained, and they reflect dorsiflexor cross-sectional area in children with cerebral palsy....

Die forging of the alloys Az80 and Zk60

NARCIS (Netherlands)

Kurz, G.; Clauw, B.; Sillekens, W.H.; Letzig, D.

2009-01-01

Overall goal of the MagForge project is to provide tailored and cost-effective technologies for the industrial manufacturing of magnesium forged components. Scientific and technological aspects are new alloys/feedstock materials with improved performance, forging process modeling and design tools

Current forgings and their properties for steam generator of nuclear plant

International Nuclear Information System (INIS)

Tsukada, Hisashi; Suzuki, Komei; Kusuhashi, Mikio; Sato, Ikuo

1997-01-01

Current steel forgings for steam generator (SG) of PWR plant are reviewed in the aspect of design and material improvement. The following three items are introduced. The use of integral type steel forgings for the fabrication of steam generator enhances the structural integrity and makes easier fabrication and inspection including in-service inspection. The following examples of current integral type forgings developed by the Japan Steel Works, Ltd. (JSW) are introduced: (1) primary head integrated with nozzles, manways and supports; (2) steam drum head integrated with nozzle and handhole; (3) conical shell integrated with cylindrical sections and handholes. In order to decrease the weight of steam generator, the high strength materials such as SA508, Cl.3a steel have been adopted in some cases. The properties of this steel are introduced and the chemistry and heat treatment condition are discussed. As one of the methods to minimize the macro- and micro-segregations, the use of vacuum carbon deoxidation (VCD), i.e. deoxidization of steel by gaseous CO reaction, with addition of Al for grain refining was investigated. The properties of SA508, Cl.3 steels with Low Si content are compared with those of conventional one

Current forgings and their properties for steam generator of nuclear plant

Energy Technology Data Exchange (ETDEWEB)

Tsukada, Hisashi; Suzuki, Komei; Kusuhashi, Mikio; Sato, Ikuo [Japan Steel Works Ltd., Muroran (Japan)

1997-12-31

Current steel forgings for steam generator (SG) of PWR plant are reviewed in the aspect of design and material improvement. The following three items are introduced. The use of integral type steel forgings for the fabrication of steam generator enhances the structural integrity and makes easier fabrication and inspection including in-service inspection. The following examples of current integral type forgings developed by the Japan Steel Works, Ltd. (JSW) are introduced: (1) primary head integrated with nozzles, manways and supports; (2) steam drum head integrated with nozzle and handhole; (3) conical shell integrated with cylindrical sections and handholes. In order to decrease the weight of steam generator, the high strength materials such as SA508, Cl.3a steel have been adopted in some cases. The properties of this steel are introduced and the chemistry and heat treatment condition are discussed. As one of the methods to minimize the macro- and micro-segregations, the use of vacuum carbon deoxidation (VCD), i.e. deoxidization of steel by gaseous CO reaction, with addition of Al for grain refining was investigated. The properties of SA508, Cl.3 steels with Low Si content are compared with those of conventional one.

Sintering and densification; new techniques: sinter forging

International Nuclear Information System (INIS)

Winnubst, A.J.A.

1998-01-01

In this chapter pressure assisted sintering methods will be described. Attention will mainly be paid to sinter forging as a die-wall free uniaxial pressure sintering technique, where large creep strains are possible. Sinter forging is an effective tool to reduce sintering temperature and time and to obtain a nearly theoretically dense ceramic. In this way grain size in tetragonal zirconia ceramics can be reduced down to 100 nm. Another important phenomenon is the reduction of the number density and size of cracks and flaws resulting in higher strength and improved reliability, which is of utmost importance for engineering ceramics. The creep deformation during sinter forging causes a rearrangement of the grains resulting in a reduction of interatomic spaces between grains, while grain boundary (glassy) phases can be removed. The toughness and in some cases the wear resistance is enhanced after sinter forging as a result of the grain-boundary-morphology improvement. (orig.)

A-508 class 3 forgings for pressure vessels

International Nuclear Information System (INIS)

Comon, J.

1977-01-01

The manufacture of the forged parts of the first PWR nuclear pressure vessel installed in France started in the Creusot-Loire's Forge Plant in 1961. Since this date, more than 300 forgings of this type were delivered (flanges, rings, zones, and nozzles). The major part of these forgings were made of Mn, Ni, Mo steel (SA 508 class 3). They represent a population large and homogeneous enough to attempt a statistical analysis of chemical and mechanical test results. The aim of this analysis was double: (1) a better knowledge of the scattering of the results and a better estimate of what can be introduced or accepted in a specification, and (2) the setting up of correlations existing between these results, particularly between chemical analysis and mechanical test results. In addition to this statistical analysis concerning industrial results, several laboratory studies are presented, giving a more complete characterization of SA 508 class 3. All these results form a very complete documentation showing that SA 508 class 3 steel is suitable for the manufacture of large forged vessels requiring a high degree of reliability

Effect of Laser Preheating AISI 4140 Specimens for Micro-Forging

Directory of Open Access Journals (Sweden)

Jung C.

2017-06-01

Full Text Available Many high performance and permanent service parts require suitable material characteristics-high fatigue strength is one of the most important characteristics. For this reason, surface treatment processes are essential to increase the material performance and avoid the use of costly ineffective material. There exist various surface treatment processes for various applications. Each process has advantages and disadvantages and hybridization can solve various problems. The micro-forging process delivers a controlled and uniform surface hardness, but the depth of the forged surface is limited. On the other hand, laser heat treatment can increase the hardness drastically, but the surface may become brittle, which reduces the fatigue life. Laser-assisted micro-forging is a novel hybrid process of laser heat treatment and micro-forging that has the potential to increase the forging depth and relax the stress caused by the high temperature of the forging process.

The effect of strain distribution on microstructural developments during forging in a newly developed nickel base superalloy

Energy Technology Data Exchange (ETDEWEB)

Buckingham, R.C. [Institute of Structural Materials, Swansea University, Bay Campus, Fabian Way, Swansea SA1 8EN (United Kingdom); Argyrakis, C.; Hardy, M.C. [Rolls-Royce plc, PO Box 31, Derby DE24 8BJ (United Kingdom); Birosca, S., E-mail: 522042@swansea.ac.uk [Institute of Structural Materials, Swansea University, Bay Campus, Fabian Way, Swansea SA1 8EN (United Kingdom)

2016-01-27

In the current study, the effect of strain distribution in a simple forging geometry on the propensity for recrystallization, and its impact on mechanical properties has been investigated in a newly developed experimental nickel-based superalloy. The new alloy was produced via a Powder Metallurgy (PM) route and was subsequently Hot Isostatic Processed (HIP), isothermally forged, and heat treated to produce a coarse grain microstructure with average grain size of 23–32 μm. The alloy was examined by means of Electron Back-Scatter Diffraction (EBSD) to characterise the microstructural features such as grain orientation and morphology, grain boundary characteristics and the identification of potential Prior Particle Boundaries (PPBs) throughout each stage of the processing route. Results at the central region of the cross-section plane parallel to the loading direction showed significant microstructural differences across the forging depth. This microstructural variation was found to be highly dependent on the value of local strain imparted during forging such that areas of low effective strain showed partial recrystallisation and a necklace grain structure was observed following heat treatment. Meanwhile, a fully recrystallised microstructure with no PPBs was observed in the areas of high strain values, in the central region of the forging.

Medium carbon vanadium steels for closed die forging

International Nuclear Information System (INIS)

Jeszensky, Gabor; Plaut, Ronald Lesley

1993-01-01

This work analyses the medium carbon micro alloyed vanadium potential for closed die forged production. The steels reach the mechanical resistance requests during cooling after forging, eliminating the subsequent thermal treatment. Those steels also present good fatigue resistance and machinability. The industrial scale experiments are also reported

Gear hot forging process robust design based on finite element method

International Nuclear Information System (INIS)

Xuewen, Chen; Won, Jung Dong

2008-01-01

During the hot forging process, the shaping property and forging quality will fluctuate because of die wear, manufacturing tolerance, dimensional variation caused by temperature and the different friction conditions, etc. In order to control this variation in performance and to optimize the process parameters, a robust design method is proposed in this paper, based on the finite element method for the hot forging process. During the robust design process, the Taguchi method is the basic robust theory. The finite element analysis is incorporated in order to simulate the hot forging process. In addition, in order to calculate the objective function value, an orthogonal design method is selected to arrange experiments and collect sample points. The ANOVA method is employed to analyze the relationships of the design parameters and design objectives and to find the best parameters. Finally, a case study for the gear hot forging process is conducted. With the objective to reduce the forging force and its variation, the robust design mathematical model is established. The optimal design parameters obtained from this study indicate that the forging force has been reduced and its variation has been controlled

Influence of segregations and hydrogen flakes on the mechanical properties of forged RPV steels

International Nuclear Information System (INIS)

Eiselt, C.C.; May, J.; Hein, H.

2013-01-01

In the frame of relevant 1970s/80s German research programs (e.g. FKS research program on component safety and others), many investigations on large forgings manufactured from Reactor Pressure Vessel (RPV) materials such as 20 MnMoNi 5 5 and 22 NiMoCr 3 7 have been performed. Lately, after ultrasonic testing hydrogen flakes in connection with segregation zones have been observed in a few RPV forgings. The earlier R and D programs contained a number of special heats, which covered a defined defect state (lower bound heats) with relevance to the recent observations of numerous UT indications in RPV forgings of two PWRs. Therefore, the results of these former research programs were now reviewed. The studies included an evaluation of the effects of macro/micro segregations as well as hydrogen flakes on the mechanical properties. As part of the mechanical technological experiments Charpy impact tests in different orientations (e.g. L-T, T-L and S-T) together with fracture mechanics and large scale tensile tests were carried out in segregated and non segregated material zones. In this context the letters L,T,S indicate the longitudinal, transversal and short transverse (thickness) direction with respect to rolling direction of the forging axis. The first letter indicates the direction of the principal stress, while the second letter stands for the crack propagation direction [1]. Furthermore the irradiation behavior of segregated material regions was analyzed and compared to non segregated material regions. Key results of these analyses indicate that in most cases upper shelf levels are lowered in segregated material parts compared to non segregated areas. In addition the segregations cause a larger scattering of impact energies. A high hydrogen content in combination with segregations has overall detrimental effects on the mechanical properties. However, there seems to be no specific segregation influence on the materials' irradiation reaction.

Influence of Casting Section Thickness on Fatigue Strength of Austempered Ductile Iron

Science.gov (United States)

Olawale, J. O.; Ibitoye, S. A.

2017-10-01

The influence of casting section thickness on fatigue strength of austempered ductile iron was investigated in this study. ASTM A536 65-45-12 grade of ductile iron was produced, machined into round samples of 10, 15, 20 and 25 mm diameter, austenitized at a temperature of 820 °C, quenched into an austempering temperature (TA) of 300 and 375 °C and allowed to be isothermally transformed at these temperatures for a fixed period of 2 h. From the samples, fatigue test specimens were machined to conform to ASTM E-466. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) methods were used to characterize microstructural morphology and phase distribution of heat-treated samples. The fatigue strength decreases as the section thickness increases. The SEM image and XRD patterns show a matrix of acicular ferrite and carbon-stabilized austenite with ferrite coarsening and volume fraction of austenite reducing as the section thickness increases. The study concluded that the higher the value of carbon-stabilized austenite the higher the fatigue strength while it decreases as the ausferrite structure becomes coarse.

First Results of Energy Saving at Process Redesign of Die Forging Al-Alloys

International Nuclear Information System (INIS)

Pepelnjak, Tomaz; Kuzman, Karl; Kokol, Anton

2011-01-01

The contribution deals with eco-friendly solutions for shortened production chains of forging light alloys. During the die forging operations a remarkable amount of material goes into the flash and later on into chips during finish machining. These low value side products are rich with embedded energy therefore recycling or reprocessing could be very energy saving procedure.In cooperation with a die forging company a shortened reprocessing cycle has been studied starting from re-melting the forging flash and without additional heating to cast preforms for subsequent die forging. As such preforms have not as good formability characteristics as those done from extruded billets the isothermal forging process has been adopted. First results showed that without cracks and other defects the formability is sufficient for a broad spectrum of forgings.To improve the formability a homogenization process of cast preforms has been implemented. As the process started immediately after casting, amount of additional energy for heating was minimized. To reduce voids forging process was redesigned in a way to assure greater hydrostatic pressures in parts during forging. First results were promising therefore research is going towards improving processes without adding significantly more energy as it is needed for casting with homogenization and die forging.

77 FR 14445 - Application for a License To Export Steel Forging

Science.gov (United States)

2012-03-09

... NUCLEAR REGULATORY COMMISSION Application for a License To Export Steel Forging Pursuant to 10 CFR 110.70(b) ``Public Notice of Receipt of an Application,'' please take notice that the Nuclear... head steel February 7, 2012 forging. forging will be XR175 machined into the 11005983 finished vessel...

Mannes of Forging and Perspectives of Knuckle Joint Presses Modernization

Directory of Open Access Journals (Sweden)

A. A. Antsifirov

2014-01-01

Full Text Available The article raises an issue to enhance technological forging capabilities on the known knuckle joint presses. It provides an illustrated overview of main design types of presses with crank-knuckle, toggle-knuckle, and knuckle joint mechanisms. The article also shows the advantages of the modernization way and improvement just of the active press equipment in terms of quality-to-price ratio, for example, as compared to the similar new foreign press equipment.It gives an overview of features, which provide forging processes owing to kinetic energy accumulated with the moving parts of the known designs of the knuckle joint presses depending on the drive actuating mechanism. Focused attention is drawn to forging on the knuckle joint presses for a time of contact with a work piece to be comparable with the duration of the work piece deformation process on hydraulic forging hammers. This allows us to forge thin-wall products with process automation compared to the forging hammers.Analysis of accumulating processes of kinetic energy by the moving parts of the knuckle joint presses has shown that presses driven by hydraulic cylinders or two screw hydraulic cylinder are the most optimal for technological operations as evidenced by references to domestic and foreign invention certificates and patents. The article presents disadvantages of forging on presses with hydraulic or pneumatic drive. It is a dependence of the deformation force, caused, mainly, by a force of the drive cylinder. The article gives linear movement rate quantities of press moving members depending on the drives of the actuating mechanism. Based on the above analysis of the features to manufacture work pieces on the knuckle joint presses, the article gives the rationale for the relevance of forging in a short period of time, provided that the moving parts of the press accumulate the required kinetic energy. This can be achieved only through modernization and improvement of forging

Optical Forging of Graphene into Three-Dimensional Shapes.

Science.gov (United States)

Johansson, Andreas; Myllyperkiö, Pasi; Koskinen, Pekka; Aumanen, Jukka; Koivistoinen, Juha; Tsai, Hung-Chieh; Chen, Chia-Hao; Chang, Lo-Yueh; Hiltunen, Vesa-Matti; Manninen, Jyrki J; Woon, Wei Yen; Pettersson, Mika

2017-10-11

Atomically thin materials, such as graphene, are the ultimate building blocks for nanoscale devices. But although their synthesis and handling today are routine, all efforts thus far have been restricted to flat natural geometries, since the means to control their three-dimensional (3D) morphology has remained elusive. Here we show that, just as a blacksmith uses a hammer to forge a metal sheet into 3D shapes, a pulsed laser beam can forge a graphene sheet into controlled 3D shapes in the nanoscale. The forging mechanism is based on laser-induced local expansion of graphene, as confirmed by computer simulations using thin sheet elasticity theory.

Development of high purity large forgings for nuclear power plants

International Nuclear Information System (INIS)

Tanaka, Yasuhiko; Sato, Ikuo

2011-01-01

The recent increase in the size of energy plants has been supported by the development of manufacturing technology for high purity large forgings for the key components of the plant. To assure the reliability and performance of the large forgings, refining technology to make high purity steels, casting technology for gigantic ingots, forging technology to homogenize the material and consolidate porosity are essential, together with the required heat treatment and machining technologies. To meet these needs, the double degassing method to reduce impurities, multi-pouring methods to cast the gigantic ingots, vacuum carbon deoxidization, the warm forging process and related technologies have been developed and further improved. Furthermore, melting facilities including vacuum induction melting and electro slag re-melting furnaces have been installed. By using these technologies and equipment, large forgings have been manufactured and shipped to customers. These technologies have also been applied to the manufacture of austenitic steel vessel components of the fast breeder reactors and components for fusion experiments.

Development of high purity large forgings for nuclear power plants

Science.gov (United States)

Tanaka, Yasuhiko; Sato, Ikuo

2011-10-01

The recent increase in the size of energy plants has been supported by the development of manufacturing technology for high purity large forgings for the key components of the plant. To assure the reliability and performance of the large forgings, refining technology to make high purity steels, casting technology for gigantic ingots, forging technology to homogenize the material and consolidate porosity are essential, together with the required heat treatment and machining technologies. To meet these needs, the double degassing method to reduce impurities, multi-pouring methods to cast the gigantic ingots, vacuum carbon deoxidization, the warm forging process and related technologies have been developed and further improved. Furthermore, melting facilities including vacuum induction melting and electro slag re-melting furnaces have been installed. By using these technologies and equipment, large forgings have been manufactured and shipped to customers. These technologies have also been applied to the manufacture of austenitic steel vessel components of the fast breeder reactors and components for fusion experiments.

Development of Oxide Dispersion Strengthened (ODS) Ferritic Steel Through Powder Forging

Science.gov (United States)

Kumar, Deepak; Prakash, Ujjwal; Dabhade, Vikram V.; Laha, K.; Sakthivel, T.

2017-04-01

Oxide dispersion strengthened (ODS) ferritic steels are candidates for cladding tubes in fast breeder nuclear reactors. In this study, an 18%Cr ODS ferritic steel was prepared through powder forging route. Elemental powders with a nominal composition of Fe-18Cr-2 W-0.2Ti (composition in wt.%) with 0 and 0.35% yttria were prepared by mechanical alloying in a Simoloyer attritor under argon atmosphere. The alloyed powders were heated in a mild steel can to 1473 K under flowing hydrogen atmosphere. The can was then hot forged. Steps of sealing, degassing and evacuation are eliminated by using powder forging. Heating ODS powder in hydrogen atmosphere ensures good bonding between alloy powders. A dense ODS alloy with an attractive combination of strength and ductility was obtained after re-forging. On testing at 973 K, a loss in ductility was observed in yttria-containing alloy. The strength and ductility increased with increase in strain rate at 973 K. Reasons for this are discussed. The ODS alloy exhibited a recrystallized microstructure which is difficult to achieve by extrusion. No prior particle boundaries were observed after forging. The forged compacts exhibited isotropic mechanical properties. It is suggested that powder forging may offer several advantages over the traditional extrusion/HIP routes for fabrication of ODS alloys.

Medium carbon vanadium micro alloyed steels for drop forging

International Nuclear Information System (INIS)

Jeszensky, Gabor; Plaut, Ronald Lesley

1992-01-01

Growing competitiveness of alternative manufacturing routes requires cost minimization in the production of drop forged components. The authors analyse the potential of medium carbon, vanadium microalloyed steels for drop forging. Laboratory and industrial experiments have been carried out emphasizing deformation and temperature cycles, strain rates and dwell times showing a typical processing path, associated mechanical properties and corresponding microstructures. The steels the required levels of mechanical properties on cooling after forging, eliminating subsequent heat treatment. The machinability of V-microalloyed steels is also improved when compared with plain medium carbon steels. (author)

Study on Manufacturing Process of Hollow Main Shaft by Open Die Forging

International Nuclear Information System (INIS)

Kwon, Yong Chul; Kang, Jong Hun; Kim, Sang Sik

2016-01-01

The main shaft is one of the key components connecting the rotor hub and gear box of a wind power generator. Typically, main shafts are manufactured by open die forging method. However, the main shaft for large MW class wind generators is designed to be hollow in order to reduce the weight. Additionally, the main shafts are manufactured by a casting process. This study aims to develop a manufacturing process for hollow main shafts by the open die forging method. The design of a forging process for a solid main shaft and hollow shaft was prepared by an open die forging process design scheme. Finite element analyses were performed to obtain the flow stress by a hot compression test at different temperature and strain rates. The control parameters of each forging process, such as temperature and effective strain, were obtained and compared to predict the suitability of the hollow main shaft forging process. Finally, high productivity reflecting material utilization ratio, internal quality, shape, and dimension was verified by the prototypes manufactured by the proposed forging process for hollow main shafts

Study on Manufacturing Process of Hollow Main Shaft by Open Die Forging

Energy Technology Data Exchange (ETDEWEB)

Kwon, Yong Chul [Gyeongnam Technopark, Changwon (Korea, Republic of); Kang, Jong Hun [Jungwon Univ., Goisan (Korea, Republic of); Kim, Sang Sik [Gyeongsang Natiional Univ., Jinju (Korea, Republic of)

2016-02-15

The main shaft is one of the key components connecting the rotor hub and gear box of a wind power generator. Typically, main shafts are manufactured by open die forging method. However, the main shaft for large MW class wind generators is designed to be hollow in order to reduce the weight. Additionally, the main shafts are manufactured by a casting process. This study aims to develop a manufacturing process for hollow main shafts by the open die forging method. The design of a forging process for a solid main shaft and hollow shaft was prepared by an open die forging process design scheme. Finite element analyses were performed to obtain the flow stress by a hot compression test at different temperature and strain rates. The control parameters of each forging process, such as temperature and effective strain, were obtained and compared to predict the suitability of the hollow main shaft forging process. Finally, high productivity reflecting material utilization ratio, internal quality, shape, and dimension was verified by the prototypes manufactured by the proposed forging process for hollow main shafts.

Evolution of A-Type Macrosegregation in Large Size Steel Ingot After Multistep Forging and Heat Treatment

Science.gov (United States)

Loucif, Abdelhalim; Ben Fredj, Emna; Harris, Nathan; Shahriari, Davood; Jahazi, Mohammad; Lapierre-Boire, Louis-Philippe

2018-06-01

A-type macrosegregation refers to the channel chemical heterogeneities that can be formed during solidification in large size steel ingots. In this research, a combination of experiment and simulation was used to study the influence of open die forging parameters on the evolution of A-type macrosegregation patterns during a multistep forging of a 40 metric ton (MT) cast, high-strength steel ingot. Macrosegregation patterns were determined experimentally by macroetch along the longitudinal axis of the forged and heat-treated ingot. Mass spectroscopy, on more than 900 samples, was used to determine the chemical composition map of the entire longitudinal sectioned surface. FORGE NxT 1.1 finite element modeling code was used to predict the effect of forging sequences on the morphology evolution of A-type macrosegregation patterns. For this purpose, grain flow variables were defined and implemented in a large scale finite element modeling code to describe oriented grains and A-type segregation patterns. Examination of the A-type macrosegregation showed four to five parallel continuous channels located nearly symmetrical to the axis of the forged ingot. In some regions, the A-type patterns became curved or obtained a wavy form in contrast to their straight shape in the as-cast state. Mass spectrometry analysis of the main alloying elements (C, Mn, Ni, Cr, Mo, Cu, P, and S) revealed that carbon, manganese, and chromium were the most segregated alloying elements in A-type macrosegregation patterns. The observed differences were analyzed using thermodynamic calculations, which indicated that changes in the chemical composition of the liquid metal can affect the primary solidification mode and the segregation intensity of the alloying elements. Finite element modeling simulation results showed very good agreement with the experimental observations, thereby allowing for the quantification of the influence of temperature and deformation on the evolution of the shape of the

Optimising mechanical properties of hot forged nickel superalloy 625 components

Science.gov (United States)

Singo, Nthambe; Coles, John; Rosochowska, Malgorzata; Lalvani, Himanshu; Hernandez, Jose; Ion, William

2018-05-01

Hot forging and subsequent heat treatment were resulting in substandard mechanical properties of nickel superalloy, Alloy 625, components. The low strength was found to be due to inadequate deformation during forging, excessive grain growth and precipitation of carbides during subsequent heat treatment. Experimentation in a drop forging company and heat treatment facility led to the establishment of optimal parameters to minimise grain size and mitigate the adverse effects of carbide precipitation, leading to successful fulfilment of mechanical property specifications. This was achieved by reducing the number of operations, maximising the extent of deformation by changing the slug dimensions and its orientation in the die, and minimising the time of exposure to elevated temperatures in both the forging and subsequent heat treatment processes to avoid grain growth.

Using of material-technological modelling for designing production of closed die forgings

Science.gov (United States)

Ibrahim, K.; Vorel, I.; Jeníček, Š.; Káňa, J.; Aišman, D.; Kotěšovec, V.

2017-02-01

Production of forgings is a complex and demanding process which consists of a number of forging operations and, in many cases, includes post-forge heat treatment. An optimized manufacturing line is a prerequisite for obtaining prime-quality products which in turn are essential to profitable operation of a forging company. Problems may, however, arise from modifications to the manufacturing route due to changing customer needs. As a result, the production may have to be suspended temporarily to enable changeover and optimization. Using material-technological modelling, the required modifications can be tested and optimized under laboratory conditions outside the plant without disrupting the production. Thanks to material-technological modelling, the process parameters can be varied rapidly in response to changes in market requirements. Outcomes of the modelling runs include optimum parameters for the forging part’s manufacturing route, values of mechanical properties, and results of microstructure analysis. This article describes the use of material-technological modelling for exploring the impact of the amount of deformation and the rate of cooling of a particular forged part from the finish-forging temperature on its microstructure and related mechanical properties.

Study on isothermal precision forging process of rare earth intensifying magnesium alloy

International Nuclear Information System (INIS)

Shan, Debin; Xu, Wenchen; Han, Xiuzhu; Huang, Xiaolei

2012-01-01

A three dimensional rigid-plastic finite element model is established to simulate the isothermal precision forging process of the magnesium alloy bracket based on DEFORM 3D in order to analyze the material flow rule and determine the forging process scheme. Some problems such as underfilling and too large forging pressure are predicted and resolved through optimizing the shapes of the billet successfully. Compared to the initial microstructure, the isothermal-forged microstructure of the alloy refines obviously and amounts of secondary phases precipitate on the matrix during isothermal forging process. In subsequent ageing process, large quantities of secondary phases precipitate from α-Mg matrix with increasing ageing time. The optimal comprehensive mechanical properties of the alloy have been obtained after aged at 473 K, 63 h with the ultimate tensile strength, tensile yield strength and elongation 380 MPa, 243 MPa and 4.07% respectively, which shows good potential for application of isothermal forging process of rare earth intensifying magnesium alloy.

Sensitivity analysis and optimization algorithms for 3D forging process design

International Nuclear Information System (INIS)

Do, T.T.; Fourment, L.; Laroussi, M.

2004-01-01

This paper presents several approaches for preform shape optimization in 3D forging. The process simulation is carried out using the FORGE3 registered finite element software, and the optimization problem regards the shape of initial axisymmetrical preforms. Several objective functions are considered, like the forging energy, the forging force or a surface defect criterion. Both deterministic and stochastic optimization algorithms are tested for 3D applications. The deterministic approach uses the sensitivity analysis that provides the gradient of the objective function. It is obtained by the adjoint-state method and semi-analytical differentiation. The study of stochastic approaches aims at comparing genetic algorithms and evolution strategies. Numerical results show the feasibility of such approaches, i.e. the achieving of satisfactory solutions within a limited number of 3D simulations, less than fifty. For a more industrial problem, the forging of a gear, encouraging optimization results are obtained

High yttria ferritic ODS steels through powder forging

Energy Technology Data Exchange (ETDEWEB)

Kumar, Deepak [Department of Metallurgical and Materials Engineering, I.I.T-Roorkee, Uttarakhand 247667 (India); Prakash, Ujjwal, E-mail: ujwalfmt@iitr.ac.in [Department of Metallurgical and Materials Engineering, I.I.T-Roorkee, Uttarakhand 247667 (India); Dabhade, Vikram V. [Department of Metallurgical and Materials Engineering, I.I.T-Roorkee, Uttarakhand 247667 (India); Laha, K.; Sakthivel, T. [Mechanical Metallurgy Group, IGCAR, Kalpakkam, Tamilnadu 603102 (India)

2017-05-15

Oxide dispersion strengthened (ODS) steels are being developed for future nuclear reactors. ODS Fe-18%Cr-2%W-0.2%Ti steels with 0, 0.35, 0.5, 1 and 1.5% Y{sub 2}O{sub 3} (all compositions in weight%) dispersion were fabricated by mechanical alloying of elemental powders. The powders were placed in a mild steel can and forged in a stream of hydrogen gas at 1473 K. The steels were forged again to final density. The strength of ODS steel increased with yttria content. Though this was accompanied by a decrease in tensile elongation, all the steels showed significant ductility. The ductility in high yttria alloys may be attributed to improved inter-particle bonding between milled powders due to reduction of surface oxides by hydrogen. This may permit development of ODS steels with yttria contents higher than the conventional limit of 0.5%. It is suggested that powder forging is a promising route to fabricate ODS steels with high yttria contents and improved ductility. - Highlights: •ODS steels with yttria contents beyond the conventional limit of 0.5 wt% were fabricated by powder forging in a hydrogen atmosphere. •All the alloys exhibited significant ductility. •This may be attributed to improved inter-particle bonding due to reduction of surface oxides by hydrogen. •Strength in excess of 300 MPa was obtained at 973 K for 0.5%, 1% and 1.5% yttria ODS alloys. •Powder forging is a promising route to fabricate ODS steels and permits development of compositions with up to 1.5% yttria.

Close toleranoe forging of chromium steel blades for powerful steam turbines

International Nuclear Information System (INIS)

Shastin, Eh.G.; Kositskij, Yu.N.; Lyubchits, G.A.

1989-01-01

Work on simulating technological process on die-forging hammer was performed in order to reduce the preparation period bringing technology of close tolerance forging of turbine blades to a commercial level. A special attention was paid to development of accurate forming of forgings of 20Kh13Sh, 12Kh13 and 15Kh11MFSh steels on screw presses with nominal effort equal to 80 and 144 MN

Cross section measurement and integral test for several activation reactions using T + d and thick-Li + d sources

International Nuclear Information System (INIS)

Dumais, J.R.; Tanaka, S.; Odano, N.; Iwasaki, S.; Sugiyama, K.

1988-01-01

Recent activities on the area of the cross section measurement for several activation reactions at Department of Nucl. Eng., Tohoku Univ. are described. The first subject is the cross section measurement for (n,2n) reaction on aluminum using the RTNS-II neutron source. Cross sections with rather small error band were obtained for the incident neutron energies from 14 to 14.7 MeV. The second one is the status of the program for the integral experiments on several reactions using the thick Li + d source at Tohoku Fast Neutron Lab. The experimental results showed the usefullness of the source as a tool for the cross section assessment. (author)

Differential cross sections in a thick brane world scenario

Science.gov (United States)

Pedraza, Omar; Arceo, R.; López, L. A.; Cerón, V. E.

2018-04-01

The elastic differential cross section is calculated at low energies for the elements He and Ne using an effective 4D electromagnetic potential coming from the contribution of the massive Kaluza-Klein modes of the 5D vector field in a thick brane scenario. The length scale is adjusted in the potential to compare with known experimental data and to set bounds for the parameter of the model.

Integral forged pump casing for the primary coolant circuit of a nuclear reactor: Development in design, forging technology, and material

International Nuclear Information System (INIS)

Austel, W.; Korbe, H.

1986-01-01

Developments in the forging of large casings for primary circuit coolant pumps for light water reactors in Germany are demonstrated beginning with the multiple forging fabricated version and ending with the integral forged type. This version is the result of the joint efforts of the pump manufacturer and the forgemaster after a cost-gain evaluation and represents an optimum solution in view of its functional and economical performance and also considering the high requirements for mechanical-technological properties, including homogeneity of the material. The development from 22 NiMoCr 3 7/A 508 Class 2 to 20 MnMoNi 5 5/A 508 Class 3 and their optimization will be demonstrated. This development is based mainly on minimizing the sulfur content and on vacuum carbon deoxidation (VCD), which results in a reduction of the A-segregations, in improving fracture toughness and isotropy, and in the desired fine-grain structure

Benefit of computer-aided detection analysis for the detection of subsolid and solid lung nodules on thin- and thick-section CT.

Science.gov (United States)

Godoy, Myrna C B; Kim, Tae Jung; White, Charles S; Bogoni, Luca; de Groot, Patricia; Florin, Charles; Obuchowski, Nancy; Babb, James S; Salganicoff, Marcos; Naidich, David P; Anand, Vikram; Park, Sangmin; Vlahos, Ioannis; Ko, Jane P

2013-01-01

The objective of our study was to evaluate the impact of computer-aided detection (CAD) on the identification of subsolid and solid lung nodules on thin- and thick-section CT. For 46 chest CT examinations with ground-glass opacity (GGO) nodules, CAD marks computed using thin data were evaluated in two phases. First, four chest radiologists reviewed thin sections (reader(thin)) for nodules and subsequently CAD marks (reader(thin) + CAD(thin)). After 4 months, the same cases were reviewed on thick sections (reader(thick)) and subsequently with CAD marks (reader(thick) + CAD(thick)). Sensitivities were evaluated. Additionally, reader(thick) sensitivity with assessment of CAD marks on thin sections was estimated (reader(thick) + CAD(thin)). For 155 nodules (mean, 5.5 mm; range, 4.0-27.5 mm)-74 solid nodules, 22 part-solid (part-solid nodules), and 59 GGO nodules-CAD stand-alone sensitivity was 80%, 95%, and 71%, respectively, with three false-positives on average (0-12) per CT study. Reader(thin) + CAD(thin) sensitivities were higher than reader(thin) for solid nodules (82% vs 57%, p thick), reader(thick) + CAD(thick), reader(thick) + CAD(thin) were 40%, 58% (p thick); false-positive rates were 1.17, 1.19, and 1.26 per case for reader(thick), reader(thick) + CAD(thick), and reader(thick) + CAD(thin), respectively. Detection of GGO nodules and solid nodules is significantly improved with CAD. When interpretation is performed on thick sections, the benefit is greater when CAD marks are reviewed on thin rather than thick sections.

Thick-target method in the measurement of inner-shell ionization cross-sections by low-energy electron impact

International Nuclear Information System (INIS)

An, Z.; Wu, Y.; Liu, M.T.; Duan, Y.M.; Tang, C.H.

2006-01-01

In this paper, we have studied the thick-target method for the measurements of atomic inner-shell ionization cross-section or X-ray production cross-section by keV electron impact. We find that in the processes of electron impact on the thick targets, the ratios of the characteristic X-ray yields of photoelectric ionization by bremsstrahlung to the total characteristic X-ray yields are Z-dependent and shell-dependent, and the ratios also show the weak energy-dependence. In addition, in the lower incident energy region (i.e. U < 5-6), the contribution from the rediffusion effect and the secondary electrons can be negligible. In general, the thick-target method can be appropriately applied to the measurements of atomic inner-shell ionization cross-sections or X-ray production cross-sections by electron impact for low and medium Z elements in the lower incident electron energy (i.e. U < 5-6). The experimental accuracies by the thick-target method can reach to the level equivalent or superior to the accuracies of experimental data based on the thin-target method. This thick-target method has been applied to the measurement of K-shell ionization cross-sections of Ni element by electron impact in this paper

Application of CAD/CAE/CAM in forging process: a review

International Nuclear Information System (INIS)

Ahmad Baharuddin Abdullah; Hamouda, A.M.S.

2005-01-01

Forging can be described as the process in which metal is plastically deformed with application of huge pressure. The process not only changes the shape but also improves the properties of the forged parts due to grain size refinement. Conventionally, the empirical trial and error method has been applied, but recently there are various tools are employed to improved product quality and economic of the process. For example, Computer Aided Design (CAD) is widely used in modeling of the process, while Computer Aided Engineering (CAE) tools have been utilized in analyzing the process. To physically demonstrate the process, Computer Aided Manufacturing (CAM) such as CNC machine has been exploited. In order to improve forging process efficiency, an integrated system that combines all advantages of CAD, CAM and CAE need to be developed. This paper presents an overview of computer aided simulation such as CAD, CAE and CAM application in forging process. (Author)

Examples on cold forged aluminium components in automotive industry

DEFF Research Database (Denmark)

Bay, Niels; Kolsgaard, A.

2000-01-01

The present paper describes the possibilites of applying cold forging for manufacturing of light weight components in aluminium. A short description of the basic cold forming processes forms the basis for describing the great variety in design of cold forged components. Examples are mainly taken ...... from automotive industry but in a few cases also from other industrial sectors to show the possibilities....

Calculation of recovery plasticity in multistage hot forging under isothermal conditions.

Science.gov (United States)

Zhbankov, Iaroslav G; Perig, Alexander V; Aliieva, Leila I

2016-01-01

A widely used method for hot forming steels and alloys, especially heavy forging, is the process of multistage forging with pauses between stages. The well-known effect which accompanies multistage hot forging is metal plasticity recovery in comparison with monotonic deformation. A method which takes into consideration the recovery of plasticity in pauses between hot deformations of a billet under isothermal conditions is proposed. This method allows the prediction of billet forming limits as a function of deformation during the forging stage and the duration of the pause between the stages. This method takes into account the duration of pauses between deformations and the magnitude of subdivided deformations. A hot isothermal upsetting process with pauses was calculated by the proposed method. Results of the calculations have been confirmed with experimental data.

Effect of Cold Forging on Microstructure and MechanicalProperties of Al/SiC Composites

Science.gov (United States)

Hanamantraygouda, M. B.; Shivakumar, B. P., Dr; Siddappa, P. N.; Sampathkumar, L.; Prashanth, L.

2018-02-01

The objective of this work was to investigate the effect of cold forging on mechanical properties and microstructural study of Al MMCs, at different wt% of SiC and forging cycle. The Al-SiC composite material was fabricated by stir casting method at different weight percentage of SiC such as 2.5, 5, 7.5 and 10%. Further, the deformation characteristics during open-die forging of Al-SiC composite at cold conditions was investigated. Cast and forged composite material was subjected to hardness test, tensile test and impact test. The grain size, microstructure behaviour was investigated using optical microscope. The results show that hardness and strength of Al-SiC composite increases and ductility decreases as compared to Al alloy in both as-cast and forged conditions. Optical microscope images showed that the distribution of SiC in Al matrix was more homogeneous in a forged composite as compared to cast one and reduction of porosity was found. Further, it showed that due to forging cycle the grain size was reduced by 30% to 35% from initial size.

Finite element simulations and experimental investigations on ductile fracture in cold forging of aluminum alloy

Science.gov (United States)

Amiri, Amir; Nikpour, Amin; Saraeian, Payam

2018-05-01

Forging is one of the manufacturing processes of aluminium parts which has two major categories: called hot and cold forging. In the cold forging, the dimensional and geometrical accuracy of final part is high. However, fracture may occur in some aluminium alloys during the process because of less workability. Fracture in cold forging can be in the form of ductile, brittle or combination of both depending on the alloy type. There are several criteria for predicting fracture in cold forging. In this study, cold forging process of 6063 aluminium alloy for three different parts is simulated in order to predict fracture. The results of numerical simulations of Freudenthal criterion is in conformity with experimental tests.

Influence of performance improvement of AP1000 nuclear island main equipment forging on manufacturing

International Nuclear Information System (INIS)

Liu Zhiying

2013-01-01

In order to comply with the 60-year design life of an AP1000 nuclear power station, higher strength and ductility requirements have been made on AP1000 nuclear island SG forgings than on CPR1000 nuclear island main equipment. In addition, bigger size of AP1000 nuclear island SG forgings increases the difficulty of manufacturing them. Insufficient recognition of these changes may cause unstable quality of forgings and possible quality problems in follow-up welding procedure. On the basis of comparison and analysis of AP1000 nuclear island SG forgings and CPR1000 nuclear island forgings, this thesis suggests clear directions for the actions we need to take. (author)

Research into Oil-based Colloidal-Graphite Lubricants for Forging of Al-based Alloys

International Nuclear Information System (INIS)

Petrov, A.; Petrov, P.; Petrov, M.

2011-01-01

The presented paper describes the topical problem in metal forging production. It deals with the choice of an optimal lubricant for forging of Al-based alloys. Within the scope of the paper, the properties of several oil-based colloidal-graphite lubricants were investigated. The physicochemical and technological properties of these lubricants are presented. It was found that physicochemical properties of lubricant compositions have an influence on friction coefficient value and quality of forgings.The ring compression method was used to estimate the friction coefficient value. Hydraulic press was used for the test. The comparative analysis of the investigated lubricants was carried out. The forging quality was estimated on the basis of production test. The practical recommendations were given to choose an optimal oil-based colloidal-graphite lubricant for isothermal forging of Al-based alloy.

Study on the microstructure of the different parts for new aluminum alloy forgings

International Nuclear Information System (INIS)

Gao Wei; Zheng Xiaojing; Wu Fu

2014-01-01

The mechanical properties of former aluminium alloy forgings cannot achieve technique demand. Because the component, dimension and preparation technology of new aluminum alloy have changed, the microstructure and mechanical properties of forgings are researched. It is concluded that the flowline of forgings has good continuity and uniformity, it does not have a prominent difference on microhardness of different parts. The results prove that the microstructure of forgings has good consistency. The matrix structure of forgings consists of fiber texture and equiaxed structure. The residual second phases, which are harmful to mechanical properties, are observed in the equiaxed structure. The center of equiaxed structure core zone, the edge of equiaxed structure transition zone and equiaxed structure edge zone should be focus on observing test, they are the sampling location of tensile property. (authors)

75 FR 70689 - Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum-Greenwood Forge Division; Currently...

Science.gov (United States)

2010-11-18

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-70,376] Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum- Greenwood Forge Division; Currently Known As Contech Forgings, LLC..., applicable to workers of Kaiser Aluminum Fabricated Products, LLC, Kaiser Aluminum-Greenwood Forge Division...

Numerical modelling of damage evolution in ingot forging

DEFF Research Database (Denmark)

Christiansen, Peter; Martins, Paulo A.F.; Bay, Niels Oluf

2015-01-01

The ingot forging process is numerically simulated applying both the Shima-Oyane porous plasticity model as a coupled damage model and the uncoupled normalized Cockcroft & Latham criterion. Four different cases including two different lower die angles (120º and 180º) and two different sizes of feed...... (400mm and 800mm) are analysed. Comparison of the simulation results with recommendations in literature on ingot forging, indicates the normalized Cockcroft & Latham damage criterion to be the most realistic of the two....

Investigation of the influence of hybrid layers on the life time of hot forging dies

Directory of Open Access Journals (Sweden)

S. Legutko

2013-04-01

Full Text Available The paper deals with the issues related in the process of drop forging with special attention paid to the durability of forging tools. It presents the results of industrial investigation of the influence of hybrid layers on hot forging dies. The effectiveness of hybrid layers type nitrided layer/PVD coating applied for extending the life of forging tools whose working surfaces are exposed to such complex exploitation conditions as, among others, cyclically varying high thermal and mechanical loads, as well as intensive abrasion at raised temperature. The examination has been performed on a set of forging tools made of Unimax steel and intended for forging steel rings of gear box synchronizer in the factory FAS in Swarzedz (Poland.

Human Chorioretinal Layer Thicknesses Measured in Macula-wide, High-Resolution Histologic Sections

Science.gov (United States)

Messinger, Jeffrey D.; Sloan, Kenneth R.; Mitra, Arnab; McGwin, Gerald; Spaide, Richard F.

2011-01-01

Purpose. To provide a comprehensive description of chorioretinal layer thicknesses in the normal human macula, including two-layer pairs that can produce a combined signal in some optical coherence tomography (OCT) devices (ganglion cell [GCL] and inner plexiform [IPL] layers and outer plexiform [OPL] and outer nuclear [ONL] layers). Methods. In 0.8-μm-thick, macula-wide sections through the foveola of 18 donors (age range, 40–92 years), 21 layers were measured at 25 locations by a trained observer and validated by a second observer. Tissue volume changes were assessed by comparing total retinal thickness in ex vivo OCT and in sections. Results. Median tissue shrinkage was 14.5% overall and 29% in the fovea. Histologic laminar boundaries resembled those in SD-OCT scans, but the shapes of the foveolar OPL and ONL differed. Histologic GCL, IPL, and OPLHenle were thickest at 0.8. to 1, 1.5, and 0.4 mm eccentricity, respectively. ONL was thickest in an inward bulge at the foveal center. At 1 mm eccentricity, GCL, INL, and OPLHenle represented 17.3% to 21.1%, 18.0% to 18.5%, and 14.2% to 16.6% of total retinal thickness, respectively. In donors ≥70 years of age, the RPE and choroid were 17.1% and 29.6% thinner and OPLHenle was 20.8% thicker than in donors macula were generated. Newer OCT systems can separate GCL from IPL and OPLHenle from ONL, with good agreement for the proportion of retinal thickness occupied by OPLHenle in OCT and histology. The thickening of OPLHenle in older eyes may reflect Müller cell hypertrophy associated with rod loss. PMID:21421869

Analytical and Experimental Characterization of Thick-Section Fiber-Metal Laminates

Science.gov (United States)

2013-06-01

laminate . The model individually models each layer of the laminate and predicts stiffness degradation as metal layers plastically deform and as prepreg ...eliminating four of the possible ECM laminates . Additionally, since at least four individual layers (two aluminum and two prepreg ) are used in FML an...AFRL-AFOSR-UK-TR-2013-0023 Analytical and Experimental Characterization of Thick- Section Fiber-Metal Laminates Dr. Rene

Microstructure evolution and mechanical properties of a particulate reinforced magnesium matrix composites forged at elevated temperatures

International Nuclear Information System (INIS)

Deng, K.K.; Wu, K.; Wang, X.J.; Wu, Y.W.; Hu, X.S.; Zheng, M.Y.; Gan, W.M.; Brokmeier, H.G.

2010-01-01

SiCp/AZ91 magnesium matrix composite was fabricated by stir casting. The as-cast ingots were cut into cylindrical billets, and then forged at different temperatures (320, 370, 420, 470 and 520 deg. C) at a constant RAM speed of 15 mm/s with 50% reduction. The microstructure evolution of the composites during forging was investigated by optical microscope, scanning electron microscope, and transmission electron microscope. The texture of the forged composites was measured by neutron diffraction. Mechanical properties of the composite at different forging temperatures were tested by tensile tests at room temperature. It was found that a strong basal plane texture formed during forging, and the intensity of basal plane texture weakened as forging temperatures increased. The particle distribution in the composite was significantly improved by hot forging. Typical microstructures were obtained after forging at different temperatures and the composite with different microstructures offered different mechanical properties during tensile test.

Analysis of Filling and Stresses in the Hot Forging Process Depending on Flange Die Shapes

International Nuclear Information System (INIS)

Kim, Jun Hyoung; Kim, Cheol

2010-01-01

Hot closed-forging process and the die used for forming an automotive flange were analyzed from the viewpoints of heat transfer, grain-flow lines, and stresses to obtain a forged product without defects such as surface cracks, laps, cold shots, and partial filling. The forging process including up-set, pre-forging, final forging and pressing forces was investigated using finite element analysis. The influence of the preform die and the ratio of the heights of the upper die to lower die on the forging process and die were investigated and a die shape (10 .deg. for the preform die, and 1.5:1 ratio for the final die) suitable to achieve successful forging was determined on the basis of a parametric study. All parametric design requirements such as strength, full filling, and a load limit of 13,000 KN were satisfied for this newly developed flange die. New dies and flanges were fabricated and investigated. Defects such as partial filling and surface cracks were not observed

Physical modeling and numerical simulation of V-die forging ingot with central void

DEFF Research Database (Denmark)

Christiansen, Peter; Hattel, Jesper Henri; Bay, Niels

2014-01-01

Numerical simulation and physical modeling performed on small-scale ingots made from pure lead, having a hole drilled through their centerline to mimic porosity, are utilized to characterize the deformation mechanics of a single open die forging compression stage and to identify the influence...... of the lower V-die angle on porosity closure and forging load requirements of large cast ingots. Results show that a lower V-die angle of 120 provides the best closure of centerline porosity without demanding the highest forging loads or developing unreasonably asymmetric shapes that may create difficulties...... in multi-stage open die forging procedures....

High yttria ferritic ODS steels through powder forging

Science.gov (United States)

Kumar, Deepak; Prakash, Ujjwal; Dabhade, Vikram V.; Laha, K.; Sakthivel, T.

2017-05-01

Oxide dispersion strengthened (ODS) steels are being developed for future nuclear reactors. ODS Fe-18%Cr-2%W-0.2%Ti steels with 0, 0.35, 0.5, 1 and 1.5% Y2O3 (all compositions in weight%) dispersion were fabricated by mechanical alloying of elemental powders. The powders were placed in a mild steel can and forged in a stream of hydrogen gas at 1473 K. The steels were forged again to final density. The strength of ODS steel increased with yttria content. Though this was accompanied by a decrease in tensile elongation, all the steels showed significant ductility. The ductility in high yttria alloys may be attributed to improved inter-particle bonding between milled powders due to reduction of surface oxides by hydrogen. This may permit development of ODS steels with yttria contents higher than the conventional limit of 0.5%. It is suggested that powder forging is a promising route to fabricate ODS steels with high yttria contents and improved ductility.

76 FR 66996 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Forging...

Science.gov (United States)

2011-10-28

... for OMB Review; Comment Request; Forging Machines ACTION: Notice. SUMMARY: The Department of Labor... collection request (ICR) titled, ``Forging Machines,'' to the Office of Management and Budget (OMB) for....218, it is mandatory for covered employers to conduct and to document periodic inspections of forging...

Design and Analysis of a Forging Die for Manufacturing of Multiple Connecting Rods

Science.gov (United States)

Megharaj, C. E.; Nagaraj, P. M.; Jeelan Pasha, K.

2016-09-01

This paper demonstrates to utilize the hammer capacity by modifying the die design such that forging hammer can manufacture more than one connecting rod in a given forging cycle time. To modify the die design study is carried out to understand the parameters that are required for forging die design. By considering these parameters, forging die is designed using design modelling tool solid edge. This new design now can produce two connecting rods in same capacity hammer. The new design is required to validate by verifying complete filing of metal in die cavities without any defects in it. To verify this, analysis tool DEFORM 3D is used in this project. Before start of validation process it is require to convert 3D generated models in to. STL file format to import the models into the analysis tool DEFORM 3D. After importing these designs they are analysed for material flow into the cavities and energy required to produce two connecting rods in new forging die design. It is found that the forging die design is proper without any defects and also energy graph shows that the forging energy required to produce two connecting rods is within the limit of that hammer capacity. Implementation of this project increases the production of connecting rods by 200% in less than previous cycle time.

Development and efficiency assessment of process lubrication for hot forging

Science.gov (United States)

Kargin, S.; Artyukh, Viktor; Ignatovich, I.; Dikareva, Varvara

2017-10-01

The article considers innovative technologies in testing and production of process lubricants for hot bulk forging. There were developed new compositions of eco-friendly water-graphite process lubricants for hot extrusion and forging. New approaches to efficiency assessment of process lubricants are developed and described in the following article. Laboratory and field results are presented.

Development of strategies for saving energy by temperature reduction in warm forging processes

Science.gov (United States)

Varela, Sonia; Santos, Maite; Vadillo, Leire; Idoyaga, Zuriñe; Valbuena, Óscar

2016-10-01

This paper is associated to the European policy of increasing efficiency in raw material and energy usage. This policy becomes even more important in sectors consuming high amount of resources, like hot forging industry, where material costs sums up to 50% of component price and energy ones are continuously raising. The warm forging shows a clear potential of raw material reduction (near-net-shape components) and also of energy saving (forging temperature under 1000°C). However and due to the increment of the energy costs, new solutions are required by the forging sector in order to reduce the temperature below 900°C. The reported research is based on several approaches to reduce the forging temperature applied to a flanged shaft of the automotive sector as demonstration case. The developed investigations have included several aspects: raw material, process parameters, tools and dies behavior during forging process and also metallographic evaluation of the forged parts. This paper summarizes analysis of the ductility and the admissible forces of the flanged shaft material Ck45 in as-supplied state (as-rolled) and also in two additional heat treated states. Hot compression and tensile tests using a GLEEBLE 3800C Thermo mechanical simulator have been performed pursuing this target. In the same way, a coupled numerical model based on Finite Element Method (FEM) has been developed to predict the material flow, the forging loads and the stresses on the tools at lower temperature with the new heat treatments of the raw material. In order to validate the previous development, experimental trials at 850 °C and 750 °C were carried out in a mechanical press and the results were very promising.

Analysis of the thermo-mechanical deformations in a hot forging tool by numerical simulation

International Nuclear Information System (INIS)

L-Cancelos, R.; Varas, F.; Viéitez, I.; Martín, E.

2016-01-01

Although programs have been developed for the design of tools for hot forging, its design is still largely based on the experience of the tool maker. This obliges to build some test matrices and correct their errors to minimize distortions in the forged piece. This phase prior to mass production consumes time and material resources, which makes the final product more expensive. The forging tools are usually constituted by various parts made of different grades of steel, which in turn have different mechanical properties and therefore suffer different degrees of strain. Furthermore, the tools used in the hot forging are exposed to a thermal field that also induces strain or stress based on the degree of confinement of the piece. Therefore, the mechanical behaviour of the assembly is determined by the contact between the different pieces. The numerical simulation allows to analyse different configurations and anticipate possible defects before tool making, thus, reducing the costs of this preliminary phase. In order to improve the dimensional quality of the manufactured parts, the work presented here focuses on the application of a numerical model to a hot forging manufacturing process in order to predict the areas of the forging die subjected to large deformations. The thermo-mechanical model developed and implemented with free software (Code-Aster) includes the strains of thermal origin, strains during forge impact and contact effects. The numerical results are validated with experimental measurements in a tooling set that produces forged crankshafts for the automotive industry. The numerical results show good agreement with the experimental tests. Thereby, a very useful tool for the design of tooling sets for hot forging is achieved. (paper)

Analysis of the thermo-mechanical deformations in a hot forging tool by numerical simulation

Science.gov (United States)

L-Cancelos, R.; Varas, F.; Martín, E.; Viéitez, I.

2016-03-01

Although programs have been developed for the design of tools for hot forging, its design is still largely based on the experience of the tool maker. This obliges to build some test matrices and correct their errors to minimize distortions in the forged piece. This phase prior to mass production consumes time and material resources, which makes the final product more expensive. The forging tools are usually constituted by various parts made of different grades of steel, which in turn have different mechanical properties and therefore suffer different degrees of strain. Furthermore, the tools used in the hot forging are exposed to a thermal field that also induces strain or stress based on the degree of confinement of the piece. Therefore, the mechanical behaviour of the assembly is determined by the contact between the different pieces. The numerical simulation allows to analyse different configurations and anticipate possible defects before tool making, thus, reducing the costs of this preliminary phase. In order to improve the dimensional quality of the manufactured parts, the work presented here focuses on the application of a numerical model to a hot forging manufacturing process in order to predict the areas of the forging die subjected to large deformations. The thermo-mechanical model developed and implemented with free software (Code-Aster) includes the strains of thermal origin, strains during forge impact and contact effects. The numerical results are validated with experimental measurements in a tooling set that produces forged crankshafts for the automotive industry. The numerical results show good agreement with the experimental tests. Thereby, a very useful tool for the design of tooling sets for hot forging is achieved.

The structural and phase state formed in construction titanium alloy by radial forging

Energy Technology Data Exchange (ETDEWEB)

Shlyakhova, Galina V.; Danilov, Vladimir I.; Orlova, Dina V.; Zuev, Lev B. [Institute of Strength Physics and Materials Science SB RAS, Tomsk (Russian Federation); Zavodchikov, Aleksandr S. [Perm State Technical University, Perm (Russian Federation)

2011-07-01

The feasibility of rod manufacture from construction titanium alloy using radial forging on a high duty machine SXK16 was investigated. The investigations were carried on for titanium rod samples using the methods of metallography, electron transmission microscophy and X-ray analysis. The results obtained are described herein. It is found that radial forging results in the formation of homogeneous fine-grained structure.Using radial forging process, high-quality items are produced. As-worked material has submicrocrystalline globular structure and an optimal α:β phase ratio. Besides, the technology is more cost-effective relative to conventional flow charts. Key words: forging, titanium alloy, fine-grain structure, substructure, pore size.

Controlled austempering of hammer forgings aimed at pseudo normalized microstructure directly after deformation

Directory of Open Access Journals (Sweden)

P. Skubisz

2017-01-01

Full Text Available The study concerns cost-effective realization of controlled thermomechanical processing (CTMP of medium-carbon and HSLA steel aimed at producing microstructure and properties equivalent to normalized condition directly after forging. The results of theoretical and physical modeling of hot forging with subsequent heat treating adopted for industrial realization in continuous manner were verified in semi-industrial conditions of a forge plant.

Research on Energy-Saving Production Scheduling Based on a Clustering Algorithm for a Forging Enterprise

Directory of Open Access Journals (Sweden)

Yifei Tong

2016-02-01

Full Text Available Energy efficiency is a buzzword of the 21st century. With the ever growing need for energy efficient and low-carbon production, it is a big challenge for high energy-consumption enterprises to reduce their energy consumption. To this aim, a forging enterprise, DVR (the abbreviation of a forging enterprise, is researched. Firstly, an investigation into the production processes of DVR is given as well as an analysis of forging production. Then, the energy-saving forging scheduling is decomposed into two sub-problems. One is for cutting and machining scheduling, which is similar to traditional machining scheduling. The other one is for forging and heat treatment scheduling. Thirdly, former forging production scheduling is presented and solved based on an improved genetic algorithm. Fourthly, the latter is discussed in detail, followed by proposed dynamic clustering and stacking combination optimization. The proposed stacking optimization requires making the gross weight of forgings as close to the maximum batch capacity as possible. The above research can help reduce the heating times, and increase furnace utilization with high energy efficiency and low carbon emissions.

Improvement of mechanical properties of zirconia-toughened alumina by sinter forging

NARCIS (Netherlands)

He, Y.; Winnubst, Aloysius J.A.; Verweij, H.; Burggraaf, Anthonie; Burggraaf, A.J.

1994-01-01

ZTA powder with a composition of 85 wt% alumina/15 wt% zirconia was prepared by a gel precipitation method. Sinter forging was performed with this powder to enhance the mechanical properties of ZTA materials. The influence of processing flaws on mechanical properties of sinter forged materials and

Comparative Thermal Aging Effects on PM-HIP and Forged Inconel 690

Science.gov (United States)

Bullens, Alexander L.; Bautista, Esteban; Jaye, Elizabeth H.; Vas, Nathaniel L.; Cain, Nathan B.; Mao, Keyou; Gandy, David W.; Wharry, Janelle P.

2018-03-01

This study compares thermal aging effects in Inconel 690 (IN690) produced by forging and powder metallurgy with hot isostatic pressing (PM-HIP). Isothermal aging is carried out over 400-800°C for up to 1000 h and then metallography and nanoindentation are utilized to relate grain microstructure with hardness and yield strength. The PM-HIP IN690 maintains a constant grain size through all aging conditions, while the forged IN690 exhibits limited grain growth at the highest aging temperature and longest aging time. The PM-HIP IN690 exhibits comparable mechanical integrity as the forged material throughout aging: hardness and yield strength are unchanged with 100 h aging, but increase after 1000 h aging at all temperatures. In both the PM-HIP and forged IN690, the Hall-Petch relationship for Ni-based superalloys predicts yield strength for 0-100 h aged specimens, but underestimates yield strength in the 1000 h aged specimens because of thermally induced precipitation.

Stereological estimation of surface area and barrier thickness of fish gills in vertical sections.

Science.gov (United States)

Da Costa, Oscar T F; Pedretti, Ana Carolina E; Schmitz, Anke; Perry, Steven F; Fernandes, Marisa N

2007-01-01

Previous morphometric methods for estimation of the volume of components, surface area and thickness of the diffusion barrier in fish gills have taken advantage of the highly ordered structure of these organs for sampling and surface area estimations, whereas the thickness of the diffusion barrier has been measured orthogonally on perpendicularly sectioned material at subjectively selected sites. Although intuitively logical, these procedures do not have a demonstrated mathematical basis, do not involve random sampling and measurement techniques, and are not applicable to the gills of all fish. The present stereological methods apply the principles of surface area estimation in vertical uniform random sections to the gills of the Brazilian teleost Arapaima gigas. The tissue was taken from the entire gill apparatus of the right-hand or left-hand side (selected at random) of the fish by systematic random sampling and embedded in glycol methacrylate for light microscopy. Arches from the other side were embedded in Epoxy resin. Reference volume was estimated by the Cavalieri method in the same vertical sections that were used for surface density and volume density measurements. The harmonic mean barrier thickness of the water-blood diffusion barrier was calculated from measurements taken along randomly selected orientation lines that were sine-weighted relative to the vertical axis. The values thus obtained for the anatomical diffusion factor (surface area divided by barrier thickness) compare favourably with those obtained for other sluggish fish using existing methods.

Fatigue in cold-forging dies: Tool life analysis

DEFF Research Database (Denmark)

Skov-Hansen, P.; Bay, Niels; Grønbæk, J.

1999-01-01

In the present investigation it is shown how the tool life of heavily loaded cold-forging dies can be predicted. Low-cycle fatigue and fatigue crack growth testing of the tool materials are used in combination with finite element modelling to obtain predictions of tool lives. In the models...... the number of forming cycles is calculated first to crack initiation and then during crack growth to fatal failure. An investigation of a critical die insert in an industrial cold-forging tool as regards the influence of notch radius, the amount and method of pre-stressing and the selected tool material...

Design and verification of thermomechanical parameters of P/M Ti6Al4V alloy forging

Energy Technology Data Exchange (ETDEWEB)

Wojtaszek, Marek, E-mail: mwojtasz@metal.agh.edu.pl; Śleboda, Tomasz

2014-12-05

Highlights: • Thermomechanical parameters of P/M Ti6Al4V alloy processing were determined. • The use of the mixture of elemental powders allows reducing manufacturing costs. • Numerical modelling allowed to elaborate favourable parameters of forging. • The industrial trials of hot forging of P/M Ti6Al4V alloy were successful. - Abstract: This work is focused on the design of technology of forging high-quality Ti6Al4V alloy by means of powder metallurgy methods. A mixture of elemental powders, with the chemical composition of that of Ti6Al4V alloy, was used as a starting material for the investigation. Powder mixtures were fully densified by hot compaction under precisely controlled conditions. The mechanical properties of the obtained compacts were examined. The mechanical behaviour of the investigated alloy powder compacts was evaluated by compression test under various thermomechanical conditions using Gleeble simulator. The microstructure of powder compacts as well as P/M alloy samples deformed in compression tests was examined. All data obtained from the experimental tests were applied as boundary conditions for numerical simulation of forging of selected forgings. Basing on the results of both plastometric tests and simulations, thermomechanical parameters of the investigated alloy forging were determined. Designed parameters of forging technology were verified by forging trials performed in industrial conditions. The quality of the obtained forgings was examined by means of computed tomography.

Effect of forging process on microstructure, mechanical and corrosion properties of biodegradable Mg-1Ca alloy

International Nuclear Information System (INIS)

Harandi, Shervin Eslami; Hasbullah Idris, Mohd; Jafari, Hassan

2011-01-01

Research highlights: → Forging temperature demonstrates more pronounced effect compared to forging speed. → Precipitation of Mg 2 Ca phase at grain boundaries accelerates corrosion rate. → Forging process doesn't provide the corrosion resistance required for bone healing. -- Abstract: The performance of Mg-1Ca alloy, a biodegradable metallic material, may be improved by hot working in order that it may be of use in bone implant applications. In this study, Mg-1Ca cast alloy was preheated to different temperatures before undergoing forging process with various forging speeds. Macro- and microstructure of the samples were examined by stereo and scanning electron microscopes (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), respectively. To determine the mechanical properties of the alloy, hardness value and plastic deformation ability of the samples were measured. To investigate the corrosion behaviour of the alloy, immersion and electrochemical tests were performed on the samples in simulated body fluid and the corrosion products were characterized by SEM/EDS. The results showed that increasing forging temperature decreased grain size led to improved hardness value and plastic deformation ability of the alloy, whereas no significant effect was observed by changing forging speed. Moreover, forging at higher temperatures led to an increase in the amount of Mg 2 Ca phase at grain boundaries resulted in higher corrosion rates. It can be concluded that although forging process improved the mechanical properties of the alloy, it does not satisfy the corrosion resistance criteria required for bone healing.

Design and verification of thermomechanical parameters of P/M Ti6Al4V alloy forging

International Nuclear Information System (INIS)

Wojtaszek, Marek; Śleboda, Tomasz

2014-01-01

Highlights: • Thermomechanical parameters of P/M Ti6Al4V alloy processing were determined. • The use of the mixture of elemental powders allows reducing manufacturing costs. • Numerical modelling allowed to elaborate favourable parameters of forging. • The industrial trials of hot forging of P/M Ti6Al4V alloy were successful. - Abstract: This work is focused on the design of technology of forging high-quality Ti6Al4V alloy by means of powder metallurgy methods. A mixture of elemental powders, with the chemical composition of that of Ti6Al4V alloy, was used as a starting material for the investigation. Powder mixtures were fully densified by hot compaction under precisely controlled conditions. The mechanical properties of the obtained compacts were examined. The mechanical behaviour of the investigated alloy powder compacts was evaluated by compression test under various thermomechanical conditions using Gleeble simulator. The microstructure of powder compacts as well as P/M alloy samples deformed in compression tests was examined. All data obtained from the experimental tests were applied as boundary conditions for numerical simulation of forging of selected forgings. Basing on the results of both plastometric tests and simulations, thermomechanical parameters of the investigated alloy forging were determined. Designed parameters of forging technology were verified by forging trials performed in industrial conditions. The quality of the obtained forgings was examined by means of computed tomography

New design of process for cold forging to improve multi-stage gas fitting

Directory of Open Access Journals (Sweden)

Han-Sung Huang

2016-04-01

Full Text Available This work develops a process that solves the problem of the formation of cracks inside forged gas fittings in the cold forging process that arises from poor forging process design. DEFORM-3D forming software was utilized, and macroscopic experiments with optical microscopy and scanning electron microscopy were conducted to investigate the processed structures and the distribution therein of metal flow lines, and to find the internal micro-cracks to determine whether the cold forging process is reasonable. Analytical results herein demonstrate that the stress and strain inside the gas fitting can be elucidated using metal forming software. Together with experimental results, they demonstrate that a concentration of stress damages the workpiece in the forming process. Moreover, as metal flow lines become narrower, the workpiece becomes more easily damaged. Consequently, the improved cold forging process that is described in this work should be utilized to reduce the occurrence of fine cracks and defects. Planning for proper die design and production, increasing the quality of products, and reducing the number of defective products promote industrial competitiveness.

Managing Tensions And Forging Creative Synergies Between ...

African Journals Online (AJOL)

Managing Tensions And Forging Creative Synergies Between Indigenous And Modern Settlement Planning Concepts And Practices: Lessons For The Design And Planning For Sustainable Settlements And Built-Forms In Southern Africa.

Strain-induced grain growth of cryomilled nanocrystalline Al in trimodal composites during forging

International Nuclear Information System (INIS)

Yao, B.; Simkin, B.; Majumdar, B.; Smith, C.; Bergh, M. van den; Cho, K.; Sohn, Y.H.

2012-01-01

Highlights: ► Grain growth of cryomilled nanocrystalline aluminum during hot forging. ► Use of hollow cone dark field imaging technique in TEM for grain size measurement. ► Grain growth model of strain, strain rate and temperature for forging optimization. - Abstract: Grain growth of nanocrystalline aluminum ( nc Al) in trimodal Al metal-matrix-composites (MMCs) during hot forging was investigated. The nc Al phase formed through cryomilling of inert gas-atomized powders in liquid nitrogen has an average grain size down to 21 nm, exhibits excellent thermal stability. However, substantial grain growth of nc Al up to 63 nm was observed when the Al MMCs were thermo-mechanically processed even at relatively low temperatures. Grain growth of the cryomilled nc Al phase in trimodal Al MMCs after hot forging was documented with respect to temperature ranging from 175 °C to 287 °C, true strain ranging from 0.4 to 1.35 and strain rate ranging from 0.1 to 0.5 s −1 . Hollow cone dark field imaging technique was employed to provide statistically confident measurements of nc Al grain size that ranged from 21 to 63 nm. An increase in forging temperature and an increase in true strain were correlated with an increase in grain size of nc Al. Results were correlated to devise a phenomenological grain growth model for forging that takes strain, strain rate and temperature into consideration. Activation energy for the grain growth during thermo-mechanical hot-forging was determined to be 35 kJ/mol, approximately a quarter of activation energy for bulk diffusion of Al and a half of activation energy for static recrystallization.

Weld repair issues in thick section austenitic pipework

International Nuclear Information System (INIS)

Goodwin, S.J.; Price, A.T.

1989-03-01

Thick section austenitic Type 316 Stainless steel, in the solution treated condition, has been used in Central Electricity Generating Board plant in the United Kingdom for some three decades and has given good service. Repair and replacement of this material after long term service is becoming a requirement and is complicated by the precipitation hardening and sensitisation of the materials. This paper summarises the compositional, microstructural and ageing characteristics of the wrought material and weld metals and the consequences for materials properties. Post weld heat treatment options are outlined and sensitisation to stress corrosion cracking is discussed. Finally, some examples of cracking that has occurred in plant after long term operation are given and weld repair research requirements are noted. (author)

Forged Signature Distinction Using Convolutional Neural Network for Feature Extraction

Directory of Open Access Journals (Sweden)

Seungsoo Nam

2018-01-01

Full Text Available This paper proposes a dynamic verification scheme for finger-drawn signatures in smartphones. As a dynamic feature, the movement of a smartphone is recorded with accelerometer sensors in the smartphone, in addition to the moving coordinates of the signature. To extract high-level longitudinal and topological features, the proposed scheme uses a convolution neural network (CNN for feature extraction, and not as a conventional classifier. We assume that a CNN trained with forged signatures can extract effective features (called S-vector, which are common in forging activities such as hesitation and delay before drawing the complicated part. The proposed scheme also exploits an autoencoder (AE as a classifier, and the S-vector is used as the input vector to the AE. An AE has high accuracy for the one-class distinction problem such as signature verification, and is also greatly dependent on the accuracy of input data. S-vector is valuable as the input of AE, and, consequently, could lead to improved verification accuracy especially for distinguishing forged signatures. Compared to the previous work, i.e., the MLP-based finger-drawn signature verification scheme, the proposed scheme decreases the equal error rate by 13.7%, specifically, from 18.1% to 4.4%, for discriminating forged signatures.

76 FR 30200 - Forging Machines; Extension of the Office of Management and Budget's (OMB) Approval of...

Science.gov (United States)

2011-05-24

...] Forging Machines; Extension of the Office of Management and Budget's (OMB) Approval of Information... extend OMB approval of the information collection requirements contained in the Forging Machines Standard... to reduce employees' risk of death or serious injury by ensuring that forging machines used by them...

Computer Οptimization of Geometric Form of Tool and Preform for Closed-die Forging of Compressor Blade Simulator

Directory of Open Access Journals (Sweden)

A. V. Botkin

2014-07-01

Full Text Available Using the software package DEFORM 3D when developing technology of isothermal forging workpiece blades it is possible to reduce the pre-production time, to improve the quality of forgings and increase lifetime of forging dies. Computer modeling allows to predict the formation of such defects during forging as notches and wrinkles, underfilling of die impression, to estimate tool loads. Preform shape and angular position of the blade simulator were optimized in order to minimize the lateral forces generated during the forging operation.

Manufacture of large monoblock LP rotor forgings and their quality

International Nuclear Information System (INIS)

Suzuki, Akira; Kinoshita, Shushi; Kohno, Masayoshi; Miyakawa, Mutsuhiro; Kikuchi, Hideo

1986-01-01

This paper describes the manufacturing and the quality of large monoblock low pressure rotors forged from 360 ton and 420 ton ingots. To obtain good and homogenous mechanical properties throughout a rotor, a computer was used to determine the heat treatment conditions. It was found that the technique was very effective at predicting mechanical properties of a monoblock rotor. Mechanical properties including the fracture toughness and fatigue crack propagation characteristics of monoblock rotor forgings proved satisfactory. (author)

Intersubjective decision-making for computer-aided forging technology design

Science.gov (United States)

Kanyukov, S. I.; Konovalov, A. V.; Muizemnek, O. Yu.

2017-12-01

We propose a concept of intersubjective decision-making for problems of open-die forging technology design. The intersubjective decisions are chosen from a set of feasible decisions using the fundamentals of the decision-making theory in fuzzy environment according to the Bellman-Zadeh scheme. We consider the formalization of subjective goals and the choice of membership functions for the decisions depending on subjective goals. We study the arrangement of these functions into an intersubjective membership function. The function is constructed for a resulting decision, which is chosen from a set of feasible decisions. The choice of the final intersubjective decision is discussed. All the issues are exemplified by a specific technological problem. The considered concept of solving technological problems under conditions of fuzzy goals allows one to choose the most efficient decisions from a set of feasible ones. These decisions correspond to the stated goals. The concept allows one to reduce human participation in automated design. This concept can be used to develop algorithms and design programs for forging numerous types of forged parts.

The relationship between UT reported size and actual size of the defects in rotor forgings

International Nuclear Information System (INIS)

Seong, Un Hak; Kim, Jeong Tae; Park, Yun Sik

2003-01-01

In order to evaluate the reliability of rotor forgings, it is very important to know the actual size of the defects in the rotor forgings. The determination of the defect size requires the accurate non-destructive measurement. However, there may be some differences between the reported size with the ultrasonic non-destructive testing method and the actual size of defects. These differences may be a severe cause of errors in evaluation of rotor forgings. So, the calculated size with 'Master Curve' considering safety factor, which is usually larger than the reported size, has been used in evaluation of rotor forgings. The relation between the EFBH (Equivalent Flat Bottom Hole) size measured by non-destructive method and the actual size by destructive method in many rotors manufactured at Doosan was investigated. In this investigation 'Master Curve' compensating the differences between UT reported size and actual size of defects in our rotor forgings was obtainable. The applicability of this 'Master Curve' as a way of calculating the actual defect size was also investigated. For the evaluation of rotor forgings, it is expected that this 'Master Curve' may be used to determine the accurate actual size of defects.

The relationship between UT reported size and actual size of the defects in rotor forgings

International Nuclear Information System (INIS)

Seong, Un Hak; Kim, Jeong Tae; Park, Yun Sik

2003-01-01

In order to evaluate the reliability of rotor forgings, it is very important to know the actual size of the defects in the rotor forgings. The determination of the defect size requires the accurate non-destructive measurement. However, there may be some difference between the reported size with ultrasonic non-destructive testing method and the actual size of defects. These differences may be a severe cause of errors in evaluation of rotor forgings. So, the calculated size with 'Master Curve' considering safety factor, which is usually larger than the reported size, has been used in evaluation of rotor forgings. The relation between the EFBH (Equivalent Flat Bottom Hole) size measured by non-destructive method and the actual size by destructive method in many rotors manufactured at Doosan was investigated. In this investigation, 'Master Curve' compensating the differences between UT reported size and actual size of defects in our rotor forgings was obtainable. The applicability of this 'Master Curve' as a way of calculating the actual defect size was also investigated. For the evaluation of rotor forgings, it is expected that this 'Master Curve' may be used to determine the accurate actual size of defects.

Fabrication and properties of Y-Ba-Cu-O high Tc superconductor by upset-forging method

International Nuclear Information System (INIS)

Chang, Ho Jung; Kang, Kae Myung; Song, Jin Tae

1990-01-01

YBa 2 Cu 3 O 7-x oxide superconductors was fabricated by sintering process and upset-forging method, respectively, and microstructures and conduction properties were compared. There was no difference in crystal structure the (001) x-ray reflection presumably due to preferred crystal orientation of the YBa 2 Cu 3 O 7-x superconductor. Furthermore, the grain size of the 123-phase increased as the reduction ratio became larger during the upset-forging. The critical temperature for zero resistivity of both samples was almost the same, i.e., about 90K. These results have demonstrated the potential of producing YBa 2 Cu 3 O 7-x superconducting wire or tape effectively using a upset-forging method. The critical current density of the upset-forged sample, however, was lower than that of the sintered one, which fact might be ascribed to microcrack formation during fast upset-forging. (Author)

DNA Measurement of Overlapping Cell Nuclei in Thick Tissue Sections

Directory of Open Access Journals (Sweden)

Liang Ji

1997-01-01

Full Text Available The paper describes an improved image analysis procedure for measuring the DNA content of cell nuclei in thick sections of liver tissue by absorption densitometry. Whereas previous methods only permitted the analysis of isolated nuclei, the new technique enables both isolated and overlapping nuclei to be measured. A 3D segmentation procedure determines whether each object is an isolated nucleus or a pair of overlapping nuclei; in the latter case the combined optical density is redistributed to the individual nuclei. A selection procedure ensures that only complete nuclei are measured.

Nickel-base alloy forgings for advanced high temperature power plants

Energy Technology Data Exchange (ETDEWEB)

Donth, B.; Diwo, A.; Blaes, N.; Bokelmann, D. [Saarschmiede GmbH Freiformschmiede, Voelklingen (Germany)

2008-07-01

The strong efforts to reduce the CO{sub 2} emissions lead to the demand for improved thermal efficiency of coal fired power plants. An increased thermal efficiency can be realised by higher steam temperatures and pressures in the boiler and the turbine. The European development aims for steam temperatures of 700 C which requires the development and use of new materials and also associated process technology for large components. Temperatures of 700 C and above are too high for the application of ferritic steels and therefore only Nickel-Base Alloys can fulfill the required material properties. In particular the Nickel-Base Alloy A617 is the most candidate alloy on which was focused the investigation and development in several German and European programs during the last 10 years. The goal is to verify and improve the attainable material properties and ultrasonic detectability of large Alloy 617 forgings for turbine rotors and boiler parts. For many years Saarschmiede has been manufacturing nickel and cobalt alloys and is participating the research programs by developing the manufacturing routes for large turbine rotor forgings up to a maximum diameter of 1000 mm as well as for forged tubes and valve parts for the boiler side. The experiences in manufacturing and testing of very large forgings made from nickel base alloys for 700 C steam power plants are reported. (orig.)

Thick-section weldments in 21-6-9 and 316LN stainless steel for fusion energy applications

International Nuclear Information System (INIS)

Alexander, D.J.; Goodwin, G.M.

1991-01-01

The Burning Plasma Experiment (BPX), formerly known as the Compact Ignition Tokomak, will be a major advance in the design of a fusion reactor. The successful construction of fusion reactors will require extensive welding of thick-section stainless steel plates. Severe service conditions will be experienced by the structure. Operating temperatures will range from room temperature (300 K) to liquid nitrogen temperature (77 K), and perhaps even lower. The structure will be highly stressed, and subject to sudden impact loads if plasma disruptions occur. This demands a combination of high strength and high toughness from the weldments. Significant portions of the welding will be done in the field, so preweld and postweld heat treatments will be difficult. The thick sections to be welded will require a high deposition rate process, and will result in significant residual stresses in the materials. Inspection of these thick sections in complex geometries will be very difficult. All of these constraints make it essential that the welding procedures and alloys be well understood, and the mechanical properties of the welds and their heat-affected zones must be adequately characterized. The candidate alloy for structural applications in the BPX such as the magnet cases was initially selected as 21-6-9 austenitic stainless steel, and later changed to 316LN stainless steel. This study examined several possible filler materials for thick-section (25 to 50 mm) weldments in these two materials. The tensile and Charpy V-notch properties were measured at room temperature and 77 K. The fracture toughness was measured for promising materials

Estimating the thickness of ultra thin sections for electron microscopy by image statistics

DEFF Research Database (Denmark)

Sporring, Jon; Khanmohammadi, Mahdieh; Darkner, Sune

2014-01-01

We propose a method for estimating the thickness of ultra thin histological sections by image statistics alone. Our method works for images, that are the realisations of a stationary and isotropic stochastic process, and it relies on the existence of statistical image-measures that are strictly m...

Fractography analysis of tool samples used for cold forging

DEFF Research Database (Denmark)

Dahl, K.V.

2002-01-01

Three fractured tool dies used for industrial cold forging have been investigated using light optical microscopy and scanning electron microscopy. Two of the specimens were produced using the traditional Böhler P/M steel grade s790, while the lastspecimen was a third generation P/M steel produced...... using new technology developed by Böhler. All three steels have the same nominal composition of alloying elements. The failure in both types of material occurs as a crack formation at a notch inside ofthe tool. Generally the cold forging dies constructed in third generation steels have a longer lifetime...

Structural changes of radial forging die surface during service under thermo-mechanical fatigue

International Nuclear Information System (INIS)

Nematzadeh, Fardin; Akbarpour, Mohammad Reza; Kokabi, Amir Hosein; Sadrnezhaad, Seyed Khatiboleslam

2009-01-01

Radial forging is one of the modern open die forging techniques and has a wide application in producing machine parts. During operation at high temperatures, severe temperature change associated with mechanical loads and the resultant wearing of the die surface lead to intense variation in strain on the die surface. Therefore, under this operating condition, thermo-mechanical fatigue (TMF) occurs on the surface of the radial forging die. TMF decreases the life of the die severely. In the present research, different layers were deposited on a 1.2714 steel die by SMAW and GTAW, with a weld wire of UDIMET 520. The microstructure of the radial forging die surface was investigated during welding and service using an optical microscope and scanning electron microscope. The results revealed that, after welding, the structure of the radial forging die surface includes the γ matrix with a homogeneous distribution of fine semi-spherical carbides. The weld structure consisted mostly of columnar dendrites with low grain boundaries. Also, microstructural investigation of the die surface during operation showed that the weld structure of the die surface has remained without any considerable change. Only dendrites were deformed and broken. Moreover, grain boundaries of the dendrites were revealed during service.

Manufacturing of Nanostructured Rings from Previously ECAE-Processed AA5083 Alloy by Isothermal Forging

Directory of Open Access Journals (Sweden)

C. J. Luis

2013-01-01

Full Text Available The manufacturing of a functional hollow mechanical element or ring of the AA5083 alloy previously equal channel angular extrusion (ECAE processed, which presents a submicrometric microstructure, is dealt with. For this purpose, the design of two isothermal forging dies (preform and final shape is carried out using the design of experiments (DOE methodology. Moreover, after manufacturing the dies and carrying out tests so as to achieve real rings, the mechanical properties of these rings are analysed as well as their microstructure. Furthermore, a comparison between the different forged rings is made from ECAE-processed material subjected to different heat treatments, previous to the forging stage. On the other hand, the ring forging process is modelled through the use of finite element simulation in order to improve the die design and to study the force required for the isothermal forging, the damage value, and the strain the material predeformed by ECAE has undergone. With this present research work, it is intended to improve the knowledge about the mechanical properties of nanostructured material and the applicability of this material to industrial processes that allow the manufacturing of functional parts.

2016 Accomplishments. Tritium aging studies on stainless steel. Forging process effects on the fracture toughness properties of tritium-precharged stainless steel

Energy Technology Data Exchange (ETDEWEB)

Morgan, Michael J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-01-01

Forged austenitic stainless steels are used as the materials of construction for pressure vessels designed to contain tritium at high pressure. These steels are highly resistant to tritium-assisted fracture but their resistance can depend on the details of the forging microstructure. During FY16, the effects of forging strain rate and deformation temperature on the fracture toughness properties of tritium-exposed-and-aged Type 304L stainless steel were studied. Forgings were produced from a single heat of steel using four types of production forging equipment – hydraulic press, mechanical press, screw press, and high-energy-rate forging (HERF). Each machine imparted a different nominal strain rate during the deformation. The objective of the study was to characterize the J-Integral fracture toughness properties as a function of the industrial strain rate and temperature. The second objective was to measure the effects of tritium and decay helium on toughness. Tritium and decay helium effects were measured by thermally precharging the as-forged specimens with tritium gas at 34.5 MPa and 350°C and aging for up to five years at -80°C to build-in decay helium prior to testing. The results of this study show that the fracture toughness properties of the as-forged steels vary with forging strain rate and forging temperature. The effect is largely due to yield strength as the higher-strength forgings had the lower toughness values. For non-charged specimens, fracture toughness properties were improved by forging at 871°C versus 816°C and Screw-Press forgings tended to have lower fracture toughness values than the other forgings. Tritium exposures reduced the fracture toughness values remarkably to fracture toughness values averaging 10-20% of as-forged values. However, forging strain rate and temperature had little or no effect on the fracture toughness after tritium precharging and aging. The result was confirmed by fractography which indicated that fracture modes

Occupational noise exposure in small scale hand tools manufacturing (forging) industry (SSI) in Northern India.

Science.gov (United States)

Singh, Lakhwinder Pal; Bhardwaj, Arvind; Deepak, K K; Bedi, Raman

2009-08-01

Occupational noise has been recognized as hazardous for the human beings. A high noise level in forging shops is considered to lower the labour productivity and cause illness however occupational noise is being accepted as an integral part of the job. The present study has been carried out in 5 small scale hand tool forging units (SSI) of different sizes in Northern India in Punjab. Noise levels at various sections were measured. OSHA norms for hearing conservation has been incorporated which includes an exchange rate of 5 dB (A), criterion level at 90 dB (A), criterion time of 8 h, threshold level=80 dB (A), upper limit=140 dB (A) and with F/S response rate. Equivalent sound pressure level (L(eq)) has been measured in various sections of these plants. Noise at various sections like hammer section, cutting presses, punching, grinding and barrelling process was found to be >90 dB (A), which is greater than OSHA norms. A cross-sectional study on the basis of questionnaire has been carried out. The results of which revealed that 68% of the workers are not wearing ear protective equipments out of these 50% were not provided with PPE by the company. About 95% of the workers were suffering speech interference though high noise annoyance was reported by only 20%. It has been established that the maximum noise exposure is being taken by the workers as they are working more than 8h a day for six days per week. More than 90% workers are working 12 to 24 h over time per week which lead to very high noise exposure i.e. 50 to 80% per week higher than exposure time/week in USA or European countries(15, 16)).

Mechanical properties of F82H plates with different thicknesses

Energy Technology Data Exchange (ETDEWEB)

Sakasegawa, Hideo, E-mail: sakasegawa.hideo@jaea.go.jp; Tanigawa, Hiroyasu

2016-11-01

Highlights: • Mass effect, homogeneity, and anisotropy in mechanical properties were studied. • Thickness dependence of tensile property was not observed. • Thickness dependence of Charpy impact property was observed. • Appropriate mechanical properties were obtained using an electric furnace. - Abstract: Fusion DEMO reactor requires over 11,000 tons of reduced activation ferritic/martensitic steel and it is indispensable to develop the manufacturing technology for producing large-scale components of DEMO blanket with appropriate mechanical properties. This is because mechanical properties are generally degraded with increasing production volume. In this work, we focused mechanical properties of F82H–BA12 heat which was melted in a 20 tons electric arc furnace. Plates with difference thicknesses from 18 to 100 mm{sup t} were made from its ingot through forging and hot-rolling followed by heat treatments. Tensile and Charpy impact tests were then performed on plates focusing on their homogeneity and anisotropy. From the result, their homogeneity and anisotropy were not significant. No obvious differences were observed in tensile properties between the plates with different thicknesses. However, Charpy impact property changed with increasing plate thickness, i.e. the ductile brittle transition temperature of a 100 mm{sup t} thick plate was higher than that of the other thinner plates.

Transmission electron microscopy of Ti-12Mo-13Nb Alloy aged after heat forging

International Nuclear Information System (INIS)

Oliveira, Nathalia Rodrigues; Baldan, Renato; Gabriel, Sinara Borborema

2014-01-01

Metastable β-Ti alloys possess mechanical properties, in particular a elastic modulus that depends not only on its composition but also the applied thermomechanical treatments. These alloys require high mechanical strength and a low Young’s modulus to avoid stress shielding. Preliminary studies on the development of Ti- 13Nb-12Mo alloy showed than the better properties were obtained at aged at 500 ° C / 24 h after cold forging , whose microstructure consisted of bimodal α phase in the β matrix. In this work, Ti-12Mo-13Nb alloy was heat forged and aged at 500 deg C for 24h and the microstructure was analyzed by employing X-ray diffraction and transmission electron microscopy. According to the results, while the cold forging resulted in bimodal α phase in the β matrix, hot forging resulted in a fine and homogeneous α phase in the β matrix. (author)

Modelling and Testing of Friction in Forging

DEFF Research Database (Denmark)

Bay, Niels

2007-01-01

Knowledge about friction is still limited in forging. The theoretical models applied presently for process analysis are not satisfactory compared to the advanced and detailed studies possible to carry out by plastic FEM analyses and more refined models have to be based on experimental testing...

Forging Inclusive Solutions: Experiential Earth Charter Education

Science.gov (United States)

Hill, Linda D.

2010-01-01

Forging Inclusive Solutions describes the aims, methodology and outcomes of Inclusive Leadership Adventures, an experiential education curriculum for exploring the Earth Charter. Experiential education builds meaningful relationships, skills, awareness and an inclusive community based on the Earth Charter principles. When we meet people where they…

Finite element analysis for temperature distributions in a cold forging

International Nuclear Information System (INIS)

Kim, Dong Bum; Lee, In Hwan; Cho, Hae Yong; Kim, Sung Wook; Song, In Chul; Jeon, Byung Cheol

2013-01-01

In this research, the finite element method is utilized to predict the temperature distributions in a cold-forging process for a cambolt. The cambolt is mainly used as a part of a suspension system of a vehicle. The cambolt has an off-centered lobe that manipulates the vertical position of the knuckle and wheel to a slight degree. The cambolt requires certain mechanical properties, such as strength and endurance limits. Moreover, temperature is also an important factor to realize mass production and improve efficiency. However, direct measurement of temperature in a forging process is infeasible with existing technology; therefore, there is a critical need for a new technique. Accordingly, in this study, a thermo-coupled finite element method is developed for predicting the temperature distribution. The rate of energy conversion to heat for the workpiece material is determined, and the temperature distribution is analyzed throughout the forging process for a cambolt. The temperatures associated with different punch speeds are also studied, as well as the relationships between load, temperature, and punch speed. Experimental verification of the technique is presented.

Finite element analysis for temperature distributions in a cold forging

Energy Technology Data Exchange (ETDEWEB)

Kim, Dong Bum; Lee, In Hwan; Cho, Hae Yong [Chungbuk National University, Cheongju (Korea, Republic of); Kim, Sung Wook [Yanbian National University, Yanbian (China); Song, In Chul; Jeon, Byung Cheol [Sunil dyfas, Jincheon (Korea, Republic of)

2013-10-15

In this research, the finite element method is utilized to predict the temperature distributions in a cold-forging process for a cambolt. The cambolt is mainly used as a part of a suspension system of a vehicle. The cambolt has an off-centered lobe that manipulates the vertical position of the knuckle and wheel to a slight degree. The cambolt requires certain mechanical properties, such as strength and endurance limits. Moreover, temperature is also an important factor to realize mass production and improve efficiency. However, direct measurement of temperature in a forging process is infeasible with existing technology; therefore, there is a critical need for a new technique. Accordingly, in this study, a thermo-coupled finite element method is developed for predicting the temperature distribution. The rate of energy conversion to heat for the workpiece material is determined, and the temperature distribution is analyzed throughout the forging process for a cambolt. The temperatures associated with different punch speeds are also studied, as well as the relationships between load, temperature, and punch speed. Experimental verification of the technique is presented.

Sensitivity of Shallow Land Burial to neutron environment and activation cross sections in IFE thick-liquid concepts

Energy Technology Data Exchange (ETDEWEB)

Cabellos, O.; Sanz, J. [Institute of Nuclear Fusion, UPM (Spain); Cabellos, O.; Garcia-Herranz, N. [Dept. of Nuclear Engineering, UPM (Spain); Sanz, J. [Dept. of Power Engineering, UNED (Spain); Reyes, S.; Latkowski, J. [Livermore National Lab., LLNL (United States)

2006-06-15

A comprehensive assessment on the eligibility of reduced activation (RA) steels as structural chamber material in Inertial Fusion Energy thick-liquid concepts is performed. As far as alloying elements, it is shown that the activation of tungsten is a question to discuss. Regarding impurity elements, it is analyzed if they could question the possibility of obtaining real RA steels for shallow land burial (SLB). The effect of the thickness of the liquid wall on the SLB response of alloying and impurity elements is computed. It seems that a reasonable liquid thickness of about 80 cm is allowable to obtain SLB acceptability of real RA steels. And above all, we have estimated the impact of cross section uncertainties when addressing the former questions, and we identify those to be improved. The necessary improvement of some tungsten and niobium cross sections is justified. (authors)

Effect of raw materials and hardening process on hardness of manually forged knife

Science.gov (United States)

Balkhaya, Suwarno

2017-06-01

Knives are normally made by forging process either using a machine or traditional method by means of hammering process. This present work was conducted to study the effects of steel raw materials and hardening process on the hardness of manually forged knives. The knife samples were made by traditional hammering (forging) process done by local blacksmith. Afterward, the samples were heat treated with two different hardening procedures, the first was based on the blacksmith procedure and the second was systematically done at the laboratory. The forging was done in the temperature ranged between 900-950°C, while the final temperature ranged between 650-675°C. The results showed that knives made of spring steel and heat treated in simulated condition at the laboratory obtained higher level of hardness, i.e. 62 HRC. In general, knives heat treated by local blacksmith had lower level of hardness that those obtained from simulated condition. Therefore, we concluded that the traditional knife quality in term of hardness can be improved by optimizing the heat treatment schedule.

Fabrication Improvement of Cold Forging Hexagonal Nuts by Computational Analysis and Experiment Verification

Directory of Open Access Journals (Sweden)

Shao-Yi Hsia

2015-01-01

Full Text Available Cold forging has played a critical role in fasteners and has been applied to the automobile industry, construction industry, aerospace industry, and living products so that cold forging presents the opportunities for manufacturing more products. By using computer simulation, this study attempts to analyze the process of creating machine parts, such as hexagonal nuts. The DEFORM-3D forming software is applied to analyze the process at various stages in the computer simulation, and the compression test is also used for the flow stress equation in order to compare the differences between the experimental results and the equation that is built into the computer simulation software. At the same time, the metallography and hardness of experiments are utilized to understand the cold forging characteristics of hexagonal nuts. The research results would benefit machinery businesses to realize the forging load and forming conditions at various stages before the fastener formation. In addition to planning proper die design and production, the quality of the produced hexagonal nuts would be more stable to promote industrial competitiveness.

Optimizing noise control strategy in a forging workshop.

Science.gov (United States)

Razavi, Hamideh; Ramazanifar, Ehsan; Bagherzadeh, Jalal

2014-01-01

In this paper, a computer program based on a genetic algorithm is developed to find an economic solution for noise control in a forging workshop. Initially, input data, including characteristics of sound sources, human exposure, abatement techniques, and production plans are inserted into the model. Using sound pressure levels at working locations, the operators who are at higher risk are identified and picked out for the next step. The program is devised in MATLAB such that the parameters can be easily defined and changed for comparison. The final results are structured into 4 sections that specify an appropriate abatement method for each operator and machine, minimum allowance time for high-risk operators, required damping material for enclosures, and minimum total cost of these treatments. The validity of input data in addition to proper settings in the optimization model ensures the final solution is practical and economically reasonable.

Monte Carlo electron-trajectory simulations in bright-field and dark-field STEM: Implications for tomography of thick biological sections

Energy Technology Data Exchange (ETDEWEB)

Sousa, A.A.; Hohmann-Marriott, M.F.; Zhang, G. [Laboratory of Bioengineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bldg. 13, Rm. 3N17, 13 South Drive, Bethesda, MD 20892-5766 (United States); Leapman, R.D. [Laboratory of Bioengineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bldg. 13, Rm. 3N17, 13 South Drive, Bethesda, MD 20892-5766 (United States)], E-mail: leapmanr@mail.nih.gov

2009-02-15

A Monte Carlo electron-trajectory calculation has been implemented to assess the optimal detector configuration for scanning transmission electron microscopy (STEM) tomography of thick biological sections. By modeling specimens containing 2 and 3 at% osmium in a carbon matrix, it was found that for 1-{mu}m-thick samples the bright-field (BF) and annular dark-field (ADF) signals give similar contrast and signal-to-noise ratio provided the ADF inner angle and BF outer angle are chosen optimally. Spatial resolution in STEM imaging of thick sections is compromised by multiple elastic scattering which results in a spread of scattering angles and thus a spread in lateral distances of the electrons leaving the bottom surface. However, the simulations reveal that a large fraction of these multiply scattered electrons are excluded from the BF detector, which results in higher spatial resolution in BF than in high-angle ADF images for objects situated towards the bottom of the sample. The calculations imply that STEM electron tomography of thick sections should be performed using a BF rather than an ADF detector. This advantage was verified by recording simultaneous BF and high-angle ADF STEM tomographic tilt series from a stained 600-nm-thick section of C. elegans. It was found that loss of spatial resolution occurred markedly at the bottom surface of the specimen in the ADF STEM but significantly less in the BF STEM tomographic reconstruction. Our results indicate that it might be feasible to use BF STEM tomography to determine the 3D structure of whole eukaryotic microorganisms prepared by freeze-substitution, embedding, and sectioning.

Tailorable Burning Behavior of Ti14 Alloy by Controlling Semi-Solid Forging Temperature.

Science.gov (United States)

Chen, Yongnan; Yang, Wenqing; Zhan, Haifei; Zhang, Fengying; Huo, Yazhou; Zhao, Yongqing; Song, Xuding; Gu, Yuantong

2016-08-16

Semi-solid processing (SSP) is a popular near-net-shape forming technology for metals, while its application is still limited in titanium alloy mainly due to its low formability. Recent works showed that SSP could effectively enhance the formability and mechanical properties of titanium alloys. The processing parameters such as temperature and forging rate/ratio, are directly correlated with the microstructure, which endow the alloy with different chemical and physical properties. Specifically, as a key structural material for the advanced aero-engine, the burn resistant performance is a crucial requirement for the burn resistant titanium alloy. Thus, this work aims to assess the burning behavior of Ti14, a kind of burn resistant alloy, as forged at different semi-solid forging temperatures. The burning characteristics of the alloy are analyzed by a series of burning tests with different burning durations, velocities, and microstructures of burned sample. The results showed that the burning process is highly dependent on the forging temperature, due to the fact that higher temperatures would result in more Ti₂Cu precipitate within grain and along grain boundaries. Such a microstructure hinders the transport of oxygen in the stable burning stage through the formation of a kind of oxygen isolation Cu-enriched layer under the burn product zone. This work suggests that the burning resistance of the alloy can be effectively tuned by controlling the temperature during the semi-solid forging process.

On the domestically-made heavy forging for reactor pressure vessels of PWR nuclear power plant

International Nuclear Information System (INIS)

Pan Xiren; Zhang Chen.

1988-01-01

The present situation of the foreign heavy forgings for nuclear reactor pressure vessels and the heavy forgings condition which is used for the Qinshan 300MWe nuclear power plant are described. Some opinions of domestic products is proposed

THE FORMING OF MAGNESIUM ALLOY FORGINGS FOR AIRCRAFT AND AUTOMOTIVE APPLICATIONS

Directory of Open Access Journals (Sweden)

Anna Dziubińska

2016-09-01

Full Text Available The paper presents the theoretical and technological aspects of forming magnesium alloy parts for aircraft and automotive applications. The main applications of magnesium alloys in the aircraft and automotive industries are discussed. In addition, the forging technology for magnesium alloys is generally described, with a particular emphasis on wrought alloys. A brief outline of the state of the art in the forging of magnesium alloys is given based on a survey of the specialist literature and the results of previous research by the authors.

Adapted diffusion processes for effective forging dies

Science.gov (United States)

Paschke, H.; Nienhaus, A.; Brunotte, K.; Petersen, T.; Siegmund, M.; Lippold, L.; Weber, M.; Mejauschek, M.; Landgraf, P.; Braeuer, G.; Behrens, B.-A.; Lampke, T.

2018-05-01

Hot forging is an effective production method producing safety relevant parts with excellent mechanical properties. The economic efficiency directly depends on the occurring wear of the tools, which limits service lifetime. Several approaches of the presenting research group aim at minimizing the wear caused by interacting mechanical and thermal loads by using enhanced nitriding technology. Thus, by modifying the surface zone layer it is possible to create a resistance against thermal softening provoking plastic deformation and pronounced abrasive wear. As a disadvantage, intensely nitrided surfaces may possibly include the risk of increased crack sensitivity and therefore feature the chipping of material at the treated surface. Recent projects (evaluated in several industrial applications) show the high technological potential of adapted treatments: A first approach evaluated localized treatments by preventing areas from nitrogen diffusion with applied pastes or other coverages. Now, further ideas are to use this principle to structure the surface with differently designed patterns generating smaller ductile zones beneath nitrided ones. The selection of suitable designs is subject to certain geo-metrical requirements though. The intention of this approach is to prevent the formation and propagation of cracks under thermal shock conditions. Analytical characterization methods for crack sensitivity of surface zone layers and an accurate system of testing rigs for thermal shock conditions verified the treatment concepts. Additionally, serial forging tests using adapted testing geometries and finally, tests in the industrial production field were performed. Besides stabilizing the service lifetime and decreasing specific wear mechanisms caused by thermal influences, the crack behavior was influenced positively. This leads to a higher efficiency of the industrial production process and enables higher output in forging campaigns of industrial partners.

Manufacturing and material properties of forgings for reactor pressure vessel of high temperature engineering test reactor

International Nuclear Information System (INIS)

Sato, I.; Suzuki, K.

1994-01-01

For the reactor pressure vessel (RPV) of high temperature engineering test reactor (HTTR) which has been developed by Japan Atomic Energy Research Institute (JAERI), 2 1/4Cr-1Mo steel is used first in the world. Material confirmation test has been carried out to demonstrate good applicability of forged low Si 2 1/4Cr-1Mo steel to the RPV of HTTR. Recently, JSW has succeeded in the manufacturing of large size ring forgings and large size forged cover dome integrated with nozzles for stand pipe for the RPV. This paper describes the results of the material confirmation test as well as the manufacturing and material properties of the large forged cover dome integrated with nozzles for stand pipe. (orig.)

Forging a unique nursing partnership with China.

Science.gov (United States)

Munn, Flavia

2017-07-12

When members of a London nursing faculty forged a learning partnership with a Chinese counterpart they likely did not expect to be discussing the benefits of using Florence Nightingale lamps to decorate hospital walls. But there is nothing ordinary about the collaboration between King's College London and Nanjing Health School.

Modelling of Damage During Hot Forging of Ingots

DEFF Research Database (Denmark)

Christiansen, Peter; Hattel, Jesper Henri; Bay, Niels

2013-01-01

Ductile damage modelling in the ingot forging process is discussed. Advantages and disadvantages of both coupled and uncoupled ductile damage models are presented. Some uncoupled damage models are examined in greater detail regarding their applicability to different processes, where hydrostatic...

Forged hollows (alloy 617) for PNP-hot gas collectors

International Nuclear Information System (INIS)

Hofmann, F.

1984-01-01

When the partners in the PNP-Project decided to manufacture components, such as gas collectors, from material of type alloy 617, the problem arose that required semi-fabricated products, especially forged hollows weighing several tons each, were not available. As VDM (Vereinigte Deutsche Metallwerke AG) had already experience in production of other semi-fabricated products of this alloy, attempts were made based on this knowledge, to develop manufacturing methods for forged hollows. The aim was to produce hollows as long as possible, and to keep the welding cost minimum. Welded seams are always critical during fabrication, as well as during later inspection under actual operating conditions. The three stage plan used to perform the above task illustrates the development aims is described

Production of a 304 stainless steel nuclear reactor forging from a very large electroslag refined ingot

International Nuclear Information System (INIS)

Watkins, E.J.; Tihansky, E.L.

1986-01-01

A four-loop, upper barrel flange forging for a nuclear reactor was produced from what the authors believe to be the largest 304H grade stainless steel electroslag refined (ESR) ingot ever refined. The ingot was refined in a 1524-mm-diameter, ingot withdrawal-type ESR furnace using a lime-bearing slag, low-frequency a-c power, and dry air protection. Five electrodes were remelted in order to produce the desired ingot weight. The ingot was subsequently forged in a five-step operation on a 6800-metric-ton press to produce the desired barrel flange configuration. Testing of the finished machined forging revealed excellent tensile ductility, excellent ultrasonic penetrability, and good chemical uniformity with no macrosegregation. Overall quality was judged to be superior to previously produced, conventionally melted forgings

Forging Oxide-Dispersion-Strengthened Superalloys

Science.gov (United States)

Harf, F. H.; Glasgow, T. K.; Moracz, D. J.; Austin, C. M.

1986-01-01

Cladding of mild steel prevents surface cracking when alloy contacts die. Continual need for improvements in properties of alloys capable of withstanding elevated temperatures. Accomplished by using oxide-dispersion-strengthed superalloys such as Inconel Alloy MA 6000. Elevated tensile properties of forged alloy equal those of hot-rolled MA 6000 bar. Stress-rupture properties somewhat lower than those of bar stock but, at 1,100 degrees C, exceed those of strongest commercial single crystal, directionally solidified and conventionally cast superalloys.

Some elevated temperature tensile and strain-controlled fatigue properties for a 9%Cr1Mo steel heat treated to simulate thick section material

International Nuclear Information System (INIS)

Sanderson, S.J.; Jacques, S.

Current interest has been expressed in the usage of thick section 9%Cr1%Mo steel, particularly for UK Commercial Demonstration Fast Reactor (CDFR) steam generator tubeplates. This paper presents the results of some preliminary mechanical property test work on a single cast of the steel, heat treated to simulate heavy ruling sections encompassing thicknesses likely to be met in the CDFR context. The microstructures of the simulated thick section material were found to remain predominantly as tempered martensite even at the slowest transformation cooling rates used (50 deg. C/h). The effect of microstructure is reflected in the elevated temperature proof stress, tensile strength and strain-controlled fatigue endurance which were found to be comparable with the properties established for thin section normalised and tempered 9%Cr1%Mo steel. These results are extremely encouraging and, taken in conjunction with the results from other simulation work on this material, further demonstrate the potential of thick section 9%Cr1%Mo steel. (author)

Correlation between Macular Thickness and Visual Field in Early Open Angle Glaucoma: A Cross-Sectional Study.

Science.gov (United States)

Fallahi Motlagh, Behzad; Sadeghi, Ali

2017-01-01

The aim of this study was to correlate macular thickness and visual field parameters in early glaucoma. A total of 104 eyes affected with early glaucoma were examined in a cross-sectional, prospective study. Visual field testing using both standard automated perimetry (SAP) and shortwave automated perimetry (SWAP) was performed. Global visual field parameters, including mean deviation (MD) and pattern standard deviation (PSD), were recorded and correlated with spectral domain optical coherence tomography (SD-OCT)-measured macular thickness and asymmetry. Average macular thickness correlated significantly with all measures of visual field including MD-SWAP (r = 0.42), MD-SAP (r = 0.41), PSD-SWAP (r = -0.23), and PSD-SAP (r = -0.21), with P-values field parameters in early glaucoma. The results of this study should make macular thickness measurements even more meaningful to glaucoma specialists.

Highlight: Forging the new Indonesia-Canada partnership | CRDI ...

International Development Research Centre (IDRC) Digital Library (Canada)

15 avr. 2016 ... Canada's Centre for International Governance Innovation and Indonesia's Centre for Strategic and International Studies organized the Indonesia-Canada Bilateral Forum, Innovation and Change: Forging the New Indonesia-Canada Partnership. IDRC co-sponsored the meeting, held May 26-27, 2015.

Manufacturing involving forging of multiple objects in contact

DEFF Research Database (Denmark)

Nielsen, Chris Valentin; Zhang, W.; Martins, P.A.F.

and dissimilar materials. While being plastically deformed against each other under increasing forging load, the parts dynamically develop their mutual contact interfaces. Comparisons of the final geometry as well as force-displacement curves are evaluated. The potential of simulated applications are discussed...

Phased array inspection of large size forged steel parts

Science.gov (United States)

Dupont-Marillia, Frederic; Jahazi, Mohammad; Belanger, Pierre

2018-04-01

High strength forged steel requires uncompromising quality to warrant advance performance for numerous critical applications. Ultrasonic inspection is commonly used in nondestructive testing to detect cracks and other defects. In steel blocks of relatively small dimensions (at least two directions not exceeding a few centimetres), phased array inspection is a trusted method to generate images of the inside of the blocks and therefore identify and size defects. However, casting of large size forged ingots introduces changes of mechanical parameters such as grain size, the Young's modulus, the Poisson's ratio, and the chemical composition. These heterogeneities affect the wave propagation, and consequently, the reliability of ultrasonic inspection and the imaging capabilities for these blocks. In this context, a custom phased array transducer designed for a 40-ton bainitic forged ingot was investigated. Following a previous study that provided local mechanical parameters for a similar block, two-dimensional simulations were made to compute the optimal transducer parameters including the pitch, width and number of elements. It appeared that depending on the number of elements, backwall reconstruction can generate high amplitude artefacts. Indeed, the large dimensions of the simulated block introduce numerous constructive interferences from backwall reflections which may lead to important artefacts. To increase image quality, the reconstruction algorithm was adapted and promising results were observed and compared with the scattering cone filter method available in the CIVA software.

Friction and wear in hot forging of steels

International Nuclear Information System (INIS)

Daouben, E.; Dubar, L.; Dubar, M.; Deltombe, R.; Dubois, A.; Truong-Dinh, N.; Lazzarotto, L.

2007-01-01

In the field of hot forging of steels, the mastering of wear phenomena enables to save cost production, especially concerning tools. Surfaces of tools are protected thanks to graphite. The existing lubrication processes are not very well known: amount and quality of lubricant, lubrication techniques have to be strongly optimized to delay wear phenomena occurrence. This optimization is linked with hot forging processes, the lubricant layers must be tested according to representative friction conditions. This paper presents the first part of a global study focused on wear phenomena encountered in hot forging of steels. The goal is the identification of reliable parameters, in order to bring knowledge and models of wear. A prototype testing stand developed in the authors' laboratory is involved in this experimental analysis. This test is called Warm and Hot Upsetting Sliding Test (WHUST). The stand is composed of a heating induction system and a servo-hydraulic system. Workpieces taken from production can be heated until 1200 deg. C. A nitrided contactor representing the tool is heated at 200 deg. C. The contactor is then coated with graphite and rubs against the workpiece, leaving a residual track on it. Friction coefficient and surface parameters on the contactor and the workpiece are the most representative test results. The surface parameters are mainly the sliding length before defects occurrence, and the amplitude of surface profile of the contactor. The developed methodology will be first presented followed by the different parts of the experimental prototype. The results of experiment show clearly different levels of performance according to different lubricants

Superplastic forging nitride ceramics

Science.gov (United States)

Panda, P.C.; Seydel, E.R.; Raj, R.

1988-03-22

A process is disclosed for preparing silicon nitride ceramic parts which are relatively flaw free and which need little or no machining, said process comprising the steps of: (a) preparing a starting powder by wet or dry mixing ingredients comprising by weight from about 70% to about 99% silicon nitride, from about 1% to about 30% of liquid phase forming additive and from 1% to about 7% free silicon; (b) cold pressing to obtain a preform of green density ranging from about 30% to about 75% of theoretical density; (c) sintering at atmospheric pressure in a nitrogen atmosphere at a temperature ranging from about 1,400 C to about 2,200 C to obtain a density which ranges from about 50% to about 100% of theoretical density and which is higher than said preform green density, and (d) press forging workpiece resulting from step (c) by isothermally uniaxially pressing said workpiece in an open die without initial contact between said workpiece and die wall perpendicular to the direction of pressing and so that pressed workpiece does not contact die wall perpendicular to the direction of pressing, to substantially final shape in a nitrogen atmosphere utilizing a temperature within the range of from about 1,400 C to essentially 1,750 C and strain rate within the range of about 10[sup [minus]7] to about 10[sup [minus]1] seconds[sup [minus]1], the temperature and strain rate being such that surface cracks do not occur, said pressing being carried out to obtain a shear deformation greater than 30% whereby superplastic forging is effected.

Production of A356 aluminum alloy wheels by thixo-forging combined with a low superheat casting process

Directory of Open Access Journals (Sweden)

Wang Shuncheng

2013-09-01

Full Text Available The A356 aluminum alloy wheels were produced by thixo-forging combined with a low superheat casting process. The as-cast microstructure, microstructure evolution during reheating and the mechanical properties of thixo-forged wheels made from the A356 aluminum alloy were studied. The results show that the A356 aluminum alloy round billet with fine, uniform and non-dendritic grains can be obtained when the melt is cast at 635 篊. When the round billet is reheated at 600 篊 for 60 min, the non-dendritic grains are changed into spherical ones and the round billet can be easily thixo-forged into wheels. The tensile strength, yield strength and elongation of the thixo-forged wheels with T6 heat treatment are 327.6 MPa, 228.3 MPa and 7.8%, respectively, which are higher than those of a cast wheel. It is suggested that the thixo-forging combined with the low superheat casting process is an effective technique to produce aluminum alloy wheels with high mechanical properties.

strength and ductility of forged 1200 aluminum alloy reinforced

African Journals Online (AJOL)

eobe

duced cylindrical shape samples, which were homogenized at 420 ... and properties of deformed materials depend on other factors ... after the surfaces were ground with emery paper of ... Figure 2: Maximum elongation of forged and annealed.

Current steel forgings and their properties for steam generator of nuclear power plant

Energy Technology Data Exchange (ETDEWEB)

Sasaki, Tomoharu; Murai, Etsuo; Sato, Ikuo [Japan Steel Works Ltd., Muroran, Hokkaido (Japan). Muroran Plant; Suzuki, Kimiaki; Kusuhashi, Mikio; Tsukada, Hisashi [Japan Steel Works Ltd., Tokyo (Japan)

2001-06-01

On the steel forging (SF) elements for steam generator (SG) of the pressurized water type light water reactor (PWR), from a viewpoint of upgrading in their improvements of design and materials, here were described on three materials such as integrated steel forgings, high strength steel forgings, and vacuum carbon deoxidisation (VCD) steel forgings. On production of SG, by using the integrated SF, not only structural soundness of SG is upgraded, but also inspections containing inspections under production and usage become easier, to bring minimization of maintenance inspection and reduction of exposure under operation. And, in order to reduce weight of SG and upgrade seismic resistance, SA508, a Cl.3a high strength SF (620 MPa class in tensile strength) is used for some nuclear plants. Here were introduced material properties of this SF and described its chemical components and heat treatment condition. And, as a method to reduce macro- and micro-segregation of materials and to upgrade homogeneity of material property, a method combined deoxidisation of steel due to carbon monoxide reaction with crystal grain minimization due to addition of aluminum was investigated. In addition, properties of a low Si-SA508 Cl.3 steel using this method was compared with that of usual SA508 Cl.3 steel. (G.K.)

Qualitative Research of AZ31 Magnesium Alloy Aircraft Brackets Produced by a New Forging Method

Directory of Open Access Journals (Sweden)

Dziubińska A.

2016-06-01

Full Text Available The paper reports a selection of numerical and experimental results of a new closed-die forging method for producing AZ31 magnesium alloy aircraft brackets with one rib. The numerical modelling of the new forming process was performed by the finite element method.The distributions of stresses, strains, temperature and forces were examined. The numerical results confirmed that the forgings produced by the new forming method are correct. For this reason, the new forming process was verified experimentally. The experimental results showed good agreement with the numerical results. The produced forgings of AZ31 magnesium alloy aircraft brackets with one rib were then subjected to qualitative tests.

Evaluation of intergranular corrosion rate and microstructure of forged 316L round bar

International Nuclear Information System (INIS)

Lim, H. K.; Kim, Y. S.

2009-01-01

When austenitic stainless steels are heat treated in the range of 500∼850 .deg. C, the alloys are sensitized due to the formation of chromium carbide at grain boundaries and then intergranular corrosion occurs. This paper aims to evaluate the intergranular corrosion rate and microstructural change of forged 316L stainless steel. To analyze the microstructure by forging conditions, ferrite phase, sigma phase, intergranular precipitation were observed. In order to evaluate the intergranular corrosion rate. Huey test was performed by ASTM A262. On the base of microstructural observation, ferrite and sigma phases were not detected, and also intergranular precipitation was not revealed in optical microscopic observation. By ASTM A262 Practice A, step structure was shown in all forging conditions. Intergranular corrosion rate gradually increased by Huey test periods but average corrosion rate was under 0.03 mm/month

Evaluation of intergranular corrosion rate and microstructure of forged 316L round bar

Energy Technology Data Exchange (ETDEWEB)

Lim, H. K.; Kim, Y. S. [Andong National University, Andong (Korea, Republic of)

2009-12-15

When austenitic stainless steels are heat treated in the range of 500{approx}850 .deg. C, the alloys are sensitized due to the formation of chromium carbide at grain boundaries and then intergranular corrosion occurs. This paper aims to evaluate the intergranular corrosion rate and microstructural change of forged 316L stainless steel. To analyze the microstructure by forging conditions, ferrite phase, sigma phase, intergranular precipitation were observed. In order to evaluate the intergranular corrosion rate. Huey test was performed by ASTM A262. On the base of microstructural observation, ferrite and sigma phases were not detected, and also intergranular precipitation was not revealed in optical microscopic observation. By ASTM A262 Practice A, step structure was shown in all forging conditions. Intergranular corrosion rate gradually increased by Huey test periods but average corrosion rate was under 0.03 mm/month.

Numerical simulation of the dynamic recrystallization behaviour in hot precision forging helical gears

Directory of Open Access Journals (Sweden)

Feng Wei

2015-01-01

Full Text Available In hot precision forging helical gears, the dynamic recrystallization phenomena will occur, which affect the microstructure of the formed part and in turn decide their mechanical properties. To investigate the effect of deformation temperature on the dynamic recrystallization in hot precision forging helical gears, a three dimensional (3D finite element (FE model was created by coupling the thermo-mechanical model with the microstructure evolution model developed based on the hot compressive experimental data of 20CrMnTiH steel. The hot precision forging process was simulated and the effect laws of the deformation temperature on the microstructure evolution the formed part were investigated. The results show that the dynamic recrystallization volume fraction and the average grain sizes increased with the increasing deformation temperature and the higher deformation temperature is beneficial to dynamic recrystallization and grain refinement.

Ultrasonic phased arrays for nondestructive inspection of forgings

International Nuclear Information System (INIS)

Wuestenberg, H.; Rotter, B.; Klanke, H.P.; Harbecke, D.

1993-01-01

Ultrasonic examinations on large forgings like rotor shafts for turbines or components for nuclear reactors are carried out at various manufacturing stages and during in-service inspections. During the manufacture, most of the inspections are carried out manually. Special in-service conditions, such as those at nuclear pressure vessels, have resulted in the development of mechanized scanning equipment. Ultrasonic probes have improved, and well-adapted sound fields and pulse shapes and based on special imaging procedures for the representation of the reportable reflectors have been applied. Since the geometry of many forgings requires the use of a multitude of angles for the inspections in-service and during manufacture, phased-array probes can be used successfully. The main advantages of the phased-array concept, e.g. the generation of a multitude of angles with the typical increase of redundancy in detection and quantitative evaluation and the possibility to produce pictures of defect situations, will be described in this contribution

Sensitivity of Shallow Land Burial to neutron environment and activation cross sections in IFE thick-liquid concepts

Science.gov (United States)

Cabellos, O.; Sanz, J.; Reyes, S.; Latkowski, J.; García-Herranz, N.

2006-06-01

A comprehensive assessment on the eligibility of reduced activation (RA) steels as structural chamber material in Inertial Fusion Energy (IFE) thick-liquid concepts is performed. As far as alloying elements, it is shown that the activation of tungsten is a question to debate. Regarding impurity elements, it is analyzed if they could question the possibility of obtaining real RA steels for shallow land burial (SLB). The effect of the thickness of the liquid wall on the SLB response of alloying and impurity elements is computed. And above all, we have estimated the impact of cross section uncertainties when addressing the former questions, and we identify those to be improved. The necessary improvement of some tungsten and niobium cross sections is justified.

Numerical modeling of axi-symmetrical cold forging process by ``Pseudo Inverse Approach''

Science.gov (United States)

Halouani, A.; Li, Y. M.; Abbes, B.; Guo, Y. Q.

2011-05-01

The incremental approach is widely used for the forging process modeling, it gives good strain and stress estimation, but it is time consuming. A fast Inverse Approach (IA) has been developed for the axi-symmetric cold forging modeling [1-2]. This approach exploits maximum the knowledge of the final part's shape and the assumptions of proportional loading and simplified tool actions make the IA simulation very fast. The IA is proved very useful for the tool design and optimization because of its rapidity and good strain estimation. However, the assumptions mentioned above cannot provide good stress estimation because of neglecting the loading history. A new approach called "Pseudo Inverse Approach" (PIA) was proposed by Batoz, Guo et al.. [3] for the sheet forming modeling, which keeps the IA's advantages but gives good stress estimation by taking into consideration the loading history. Our aim is to adapt the PIA for the cold forging modeling in this paper. The main developments in PIA are resumed as follows: A few intermediate configurations are generated for the given tools' positions to consider the deformation history; the strain increment is calculated by the inverse method between the previous and actual configurations. An incremental algorithm of the plastic integration is used in PIA instead of the total constitutive law used in the IA. An example is used to show the effectiveness and limitations of the PIA for the cold forging process modeling.

Stainless steel forgings for nuclear chemical plants

International Nuclear Information System (INIS)

1982-02-01

This Specification covers detailed requirements for the supply of austenitic stainless steel forgings used in radioactive and corrosive areas within the Nuclear Industry. With the exception of 316S51 the materials specified are all suitable for contact with nitric acid, 316S51 being included as suitable for use in contact with sodium and other alkali metals at elevated temperatures. (author)

The Investigations of Friction under Die Surface Vibration in Cold Forging Process

DEFF Research Database (Denmark)

Jinming, Sha

investigation, and the second stage is to design and manufacture a more practical tool system which can be used to forging some industrial components with larger capacity. The high performance and power piezoelectric actuator stack as the vibration source will be used for designing the vibration system in order...... to 50% with vibration being applied in forming process. Furthermore, by using finite element method, a series of the simulations of the cold forging process under die surface excitation have been implemented in order to further understand the influence of vibration on friction, especially the influence...

Performance Assessment Method for a Forged Fingerprint Detection Algorithm

Science.gov (United States)

Shin, Yong Nyuo; Jun, In-Kyung; Kim, Hyun; Shin, Woochang

The threat of invasion of privacy and of the illegal appropriation of information both increase with the expansion of the biometrics service environment to open systems. However, while certificates or smart cards can easily be cancelled and reissued if found to be missing, there is no way to recover the unique biometric information of an individual following a security breach. With the recognition that this threat factor may disrupt the large-scale civil service operations approaching implementation, such as electronic ID cards and e-Government systems, many agencies and vendors around the world continue to develop forged fingerprint detection technology, but no objective performance assessment method has, to date, been reported. Therefore, in this paper, we propose a methodology designed to evaluate the objective performance of the forged fingerprint detection technology that is currently attracting a great deal of attention.

Plane strain forging of a niobium micro-alloyed steel

International Nuclear Information System (INIS)

Balancin, O.; Ferran L, G.; Rio de Janeiro Univ.

1984-01-01

Various termomechanical treatments were carried out on a niobium micro-alloyed steel and a low carbon steel as reference material, using an apparatus for hot phane strain forging. Control of processing variables and the presence of niobium strongly modify the austenite microstructure, which upon decomposition produces various phases such as polygonal and acicular ferrite and martensite, alone or together in variable proportions. Corresponding to this diversity of structures there is a wide variation in mechanical properties at room temperature: the initial yield point varies from 310 to 650 MPa and the reduction of area in uniaxial tension from 82 to 57% for the niobium steel. These results show that hot forging a niobium micro-alloyed steel may be a suitable manufacturing process for satisfying a wide range of specifications in a final product with low equivalent carbon. (Author) [pt

Design of a forging processing route for a gas turbine compressor disc in IMI 834

International Nuclear Information System (INIS)

Clark, G.S.

1993-01-01

The microstructure in all parts of a modern gas turbine compressor disc must be carefully controlled to give the optimum balance for resistance to creep and fatigue. This is particularly true for advanced titanium alloys such as IMI834. Dynamic recrystallisation during high temperature deformation and static recrystallisation and grain growth during heat treatment, all have a profound effect on the grain structure of the disc. These processes are affected by temperature, rate of deformation and various microstructural features. These may include the size and volume fraction of primary alpha particles and current beta grain size. The construction of a computer model to simulate the forging process must therefore take all these factors into account to fully simulate the mechanical and microstructural behaviour of the material during processing. This requires a complete characterisation of the material to formulate mechanical and microstructural constitutive equations for use in a visco-plastic finite element forging model. Similarly the forging equipment must be fully characterised so that forging processes can be accurately simulated. (orig.)

Near-liquidus forging, partial remelting and thixoforging of an AZ91D + Y magnesium alloy

International Nuclear Information System (INIS)

Zhao Zude; Chen Qiang; Hu Chuankai; Huang Shuhai; Wang Yuanqing

2009-01-01

A new route, near-liquidus forging plus partial remelting, has been developed for obtaining globular microstructures. Firstly, a material is formed by near-liquidus forging for obtaining a fine dendritic microstructure. Globular microstructure can be produced by reheating the material into the semi-solid temperature range for a period of time. In this paper, an AZ91D alloy with the addition of yttrium was prepared by near-liquidus forging. Microstructure evolution during partial remelting was studied at temperatures and for times. Tensile mechanical properties of thixoforged components were also determined. It is shown that the fine dendritic structure firstly evolves into a blocky structure during partial remelting. With prolonged holding time, the blocky structure disintegrates into polygonal solid particles. Prolonging time and increasing temperature promote a faster spheroidization. Good mechanical properties are obtained for the thixoforged AZ91D alloy with the addition of yttrium prepared by near-liquidus forging, with a yield strength of 160.9 MPa and a ultimate tensile strength of 301.7 MPa and a elongation to fracture of 9.734%.

Void consolidation during open-die forging for ultralarge rotor shafts. (1. Formulation of void-closing behavior)

International Nuclear Information System (INIS)

Ono, Shin-ichi; Minami, Katsuyuki; Ochiai, Tomoyuki; Iwadate, Tadao; Nakata, Shin-ichi.

1995-01-01

Open-die forging experiments using different die geometries under hot isothermal conditions and three-dimensional simulations using rigid-plastic finite-element method were performed to formulate a void-closing behavior using only two factors; the integral of hydrostatic stress and the equivalent strain. First, upsetting, side-upsetting and V-shape die cogging of several cylinders with a spherical void at the center are carried out and the information on the void volume reduction is obtained. Seconds, the same forgings, but without voids is treated numerically and the development of stress and strain at the location of voids is investigated. Then, by combining these results, and using regression analysis, it is found that the void volume reduction is expressed as a polynomial function of the two factors. When the polynomial function is used, various forging methods can be evaluated quantitatively in terms of void-closing behavior. Therefore it is beneficial to optimize the forging process for a large rotor shaft. (author)

Effect of Forging Parameters on Low Cycle Fatigue Behaviour of Al/Basalt Short Fiber Metal Matrix Composites

Directory of Open Access Journals (Sweden)

R. Karthigeyan

2013-01-01

Full Text Available This paper deals with metal matrix composites (MMCs of Al 7075 alloy containing different weight percentage (2.5, 5, 7.5, and 10 basalt short fiber reinforcement and unreinforced matrix alloy. The samples were produced by the permanent stir casting technique. The casting ingots were cut into blanks to be forged in single stage and double stage, using MN press and graphite-based lubricant. The microstructures and fatigue properties of the matrix alloy and MMC samples were investigated in the as cast state and in the single and double stage forging operations. The microstructure results showed that the forged sample had a uniform distribution of the basalt short fiber throughout the specimens. Evaluation of the fatigue properties showed that the forged samples had higher values than those of the as cast counterparts. After forging, the enhancement of the fatigue strength of the matrix alloy was so significant and high in the case of 2.5 and 5.0 wt. percentage basalt short fiber reinforced MMC, and there was no enhancement in 7.5 and 10 weight percentages short fiber reinforced MMCs. The fracture damage was mainly due to decohesion at the matrix-fiber interface.

Effect of forging parameters on low cycle fatigue behaviour of Al/basalt short fiber metal matrix composites.

Science.gov (United States)

Karthigeyan, R; Ranganath, G

2013-01-01

This paper deals with metal matrix composites (MMCs) of Al 7075 alloy containing different weight percentage (2.5, 5, 7.5, and 10) basalt short fiber reinforcement and unreinforced matrix alloy. The samples were produced by the permanent stir casting technique. The casting ingots were cut into blanks to be forged in single stage and double stage, using MN press and graphite-based lubricant. The microstructures and fatigue properties of the matrix alloy and MMC samples were investigated in the as cast state and in the single and double stage forging operations. The microstructure results showed that the forged sample had a uniform distribution of the basalt short fiber throughout the specimens. Evaluation of the fatigue properties showed that the forged samples had higher values than those of the as cast counterparts. After forging, the enhancement of the fatigue strength of the matrix alloy was so significant and high in the case of 2.5 and 5.0 wt. percentage basalt short fiber reinforced MMC, and there was no enhancement in 7.5 and 10 weight percentages short fiber reinforced MMCs. The fracture damage was mainly due to decohesion at the matrix-fiber interface.

Analysis of hot rolling and hot forging effects on mechanical properties and microstructure of ZrNbMoGe alloy

International Nuclear Information System (INIS)

AH Ismoyo; Parikin; Bandriyana

2014-01-01

Research on formation technique by a combined method of rolling and forging has been carried out in order to improve the mechanical properties of ZrNbMoGe alloy to be used as fuel cladding in NPP (Nuclear Power Plant) application. The effects of rolling and forging were analyzed several tests. The tests were conducted for zirconium alloy specimen with a composition of (in % wt.) 97% Zr, 0,5% Mo, 2% Nb and 0,5% Ge, where the specimen was melted with an arc-furnace. The hot rolling and forging were conducted at 900 °C and 950 °C respectively. Hardness test was carried out by using a microhardness testing machine, while microstructure examination and crystal structure analysis were conducted with an optical microscope and an X-ray diffractometer. The results show that the hardness of the alloy increase from 141.21 HV (starting material) to 210.47 HV (hot rolled material) and 365.75 HV (hot forged material). Texturing phenomenon is clearly figured on the microstructure due to hot rolling and forging process. Analysis by diffractogram also indicates that the hot rolling and forging process has influence on the crystal orientation of dominant preferred direction in the reflection plane of (10ī1), recorded from the rise of intensity counting from about 2500 to 3000. In summary, hot forging and rolling process can change the mechanical properties (hardness and texture) and microstructure of materials. (author)

The FORGE (Fate Of Repository Gases) pan European project

International Nuclear Information System (INIS)

Shaw, Richard

2010-01-01

Document available in extended abstract form only. Full text of publication follows: The multiple barrier concept is the cornerstone of all proposed schemes for underground disposal of radioactive wastes. The concept invokes a series of barriers, both engineered and natural, between the waste and the surface. Achieving this concept is the primary objective of all disposal programmes, from site appraisal and characterisation to repository design and construction. However, the performance of the repository as a whole (waste, buffer, engineering disturbed zone, host rock), and in particular its gas transport properties, are still poorly understood. Issues still to be adequately examined that relate to understanding basic processes include: dilational versus visco-capillary flow mechanisms; long-term integrity of seals, in particular gas flow along contacts; role of the EDZ as a conduit for preferential flow; laboratory to field up-scaling. Understanding gas generation and migration is thus vital in the quantitative assessment of repositories and is the focus of the research in this proposal for an integrated, multidisciplinary project. The FORGE project is a pan-European project with links to international radioactive waste management organisations, regulators and academia, specifically designed to tackle the key research issues associated with the generation and movement of repository gasses with partners from 24 organisations in 12 European countries. It is supported by funding under the European Commission FP7 Euratom programme and runs from 2009 to 2013. Of particular importance are the long-term performance of bentonite buffers, plastic clays, indurated mud-rocks and crystalline formations. Further experimental data are required to reduce uncertainty relating to the quantitative treatment of gas in performance assessment. FORGE will address these issues through a series of laboratory and field-scale experiments, including the development of new methods for up

76 FR 52313 - Heavy Forged Hand Tools (i.e., Axes & Adzes, Bars & Wedges, Hammers & Sledges, and Picks...

Science.gov (United States)

2011-08-22

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-803] Heavy Forged Hand Tools (i.e... Administration, Department of Commerce. SUMMARY: As a result of the determinations by the Department of Commerce... on heavy forged hand tools (i.e., [[Page 52314

Shape optimization of metal forming and forging products using the stress equivalent static loads calculated from a virtual model

International Nuclear Information System (INIS)

Jang, Hwan Hak; Jeong, Seong Beom; Park, Gyung Jin

2012-01-01

A shape optimization is proposed to obtain the desired final shape of forming and forging products in the manufacturing process. The final shape of a forming product depends on the shape parameters of the initial blank shape. The final shape of a forging product depends on the shape parameters of the billet shape. Shape optimization can be used to determine the shape of the blank and billet to obtain the appropriate final forming and forging products. The equivalent static loads method for non linear static response structural optimization (ESLSO) is used to perform metal forming and forging optimization since nonlinear dynamic analysis is required. Stress equivalent static loads (stress ESLs) are newly defined using a virtual model by redefining the value of the material properties. The examples in this paper show that optimization using the stress ESLs is quite useful and the final shapes of a forming and forging products are identical to the desired shapes

Family Health and Financial Literacy--Forging the Connection

Science.gov (United States)

Braun, Bonnie; Kim, Jinhee; Anderson, Elaine A.

2009-01-01

Families are at-risk of or experiencing a diminished quality of living and life in current economic times and difficult decisions are required. Health and financial literacy are the basis for wise personal and public decision making. Family and consumer sciences (FCS) professionals can forge connections between health and financial literacy to…

Forge, Arquillian, Swarm and Spring Boot: All play and no effort makes Simon a productive boy

CERN Multimedia

CERN. Geneva

2017-01-01

During this live coding session, Simon will shine some light on a range productivity tools that make software development a pleasure rather than a chore. Simon will live code 2 applications; a Java EE application, with JBoss Forge which uses JPA, Bean Validation, REST and Angular. We’ll test this application using Arquillian from within JBoss Forge. We’ll also show how a Java EE microservice can be developed in Forge and run using JBoss Swarm. The second application will be developed on Spring Boot and using JRebel we’ll rapidly develop and run a Spring application. Attendees will learn how to write code productively using tools designed for developers.

Optimization of the Hot Forging Processing Parameters for Powder Metallurgy Fe-Cu-C Connecting Rods Based on Finite Element Simulation

Science.gov (United States)

Li, Fengxian; Yi, Jianhong; Eckert, Jürgen

2017-12-01

Powder forged connecting rods have the problem of non-uniform density distributions because of their complex geometric shape. The densification behaviors of powder metallurgy (PM) connecting rod preforms during hot forging processes play a significant role in optimizing the connecting rod quality. The deformation behaviors of a connecting rod preform, a Fe-3Cu-0.5C (wt pct) alloy compacted and sintered by the powder metallurgy route (PM Fe-Cu-C), were investigated using the finite element method, while damage and friction behaviors of the material were considered in the complicated forging process. The calculated results agree well with the experimental results. The relationship between the processing parameters of hot forging and the relative density of the connecting rod was revealed. The results showed that the relative density of the hot forged connecting rod at the central shank changed significantly compared with the relative density at the big end and at the small end. Moreover, the relative density of the connecting rod was sensitive to the processing parameters such as the forging velocity and the initial density of the preform. The optimum forging processing parameters were determined and presented by using an orthogonal design method. This work suggests that the processing parameters can be optimized to prepare a connecting rod with uniform density distribution and can help to better meet the requirements of the connecting rod industry.

A two-step superplastic forging forming of semi-continuously cast AZ70 magnesium alloy

Directory of Open Access Journals (Sweden)

Pan Wang

2015-03-01

Full Text Available A two-step technology combined forging with superplastic forming has been developed to enhance the forgeability of semi-continuously cast AZ70 magnesium alloy and realize the application of the as-cast magnesium alloy in large deformation bullet shell. In the first step, fine-grained microstructure preforms that are suitable for superplastic forming were obtained by reasonably designing the size of the initial blanks with the specific height-to-diameter ratio, upsetting the blanks and subsequent annealing. In the second step, the heat treated preforms were forged into the end products at the superplastic conditions. The end products exhibit high quality surface and satisfied microstructure. Consequently, this forming technology that not only avoids complicating the material preparation but also utilizes higher strain rate superplastic provides a near net-shaped novel method on magnesium forging forming technology using as-cast billet.

Forming of Hollow Shaft Forging From Titanium Alloy Ti6Al4V by Means of Rotary Compression

Directory of Open Access Journals (Sweden)

Tomczak J.

2015-04-01

Full Text Available This paper presents chosen results of theoretical-experimental works concerning forming of hollow shafts forgings from titanium alloys, which are applied in aviation industry. At the first stage of conducted analysis, the forging forming process was modeled by means of finite element method. Calculations were made using software Simufact Forming. On the basis of performed simulations optimal parameters of rotary compression process were determined. Next, experimental tests of forging forming in laboratory conditions were made. For the research needs, a forging aggregate, designed by the Authors, was used. Conducted research works confirmed the possibility of metal forming (by means of rotary compression of hollow shafts from hard workable titanium alloys. Numerous advantages of rotary compression process, make it attractive both for low series production (aircraft industry and for mass production (automotive industry.

Numerical optimization of die geometry in open die forging

DEFF Research Database (Denmark)

Christiansen, Peter; Hattel, Jesper Henri; Bay, Niels

2013-01-01

This paper deals with numerical optimization of open die forging of large metallic ingots made by casting implying risk of defects, e.g. central pores. Different material hardening properties and die geometries are combined in order to investigate, which geometry gives rise to maximum closure...

Utilization of ultrasonic tomography for the mapping of residual stress fields in thick metal sections. Final report

International Nuclear Information System (INIS)

Hildebrand, B.P.; Hufferd, D.E.

1977-01-01

It is well known that the velocity of sound propagation through a solid is altered when a stress is applied. The velocity change is small, and dependent upon the type of wave being propagated as well as the magnitude of the stress. Sensitivity is greatest to shear wave sound with the polarization vector parallel to the direction of stress. In this case, velocity changes as great as 0.6 percent were measured. Preliminary work is described aimed at evaluating computerized reconstruction of velocity fields from velocity profiles to map residual stress concentrations in thick metal sections. Experimental results with liquid and solid models are described. One could image velocity anomalies of 0.2 percent and estimate that 0.05 percent is technically feasible. It is concluded that this technique has great potential for finding and mapping residual stress in thick metal sections

77 FR 39997 - Heavy Forged Hand Tools, Finished or Unfinished, With or Without Handles From the People's...

Science.gov (United States)

2012-07-06

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-803] Heavy Forged Hand Tools...) (Diamond Sawblades), the Department is notifying the public that the final judgment in this case is not in... review on heavy forged hand tools, finished or unfinished, with or without handles from the People's...

Standard specification for titanium and titanium alloy forgings

International Nuclear Information System (INIS)

Anon.

1975-01-01

Standards are given for the purchase, manufacture, product testing and certification, packaging, and marketing of annealed Ti and Ti-alloy forgings. The specifications apply to the following Ti alloys: 6Al-Ti-4V, 5Al-Ti-2.5 Sn, and Ti + Pd. Acceptable values for the chemical requirements, product analysis limits, and tensile requirements are tabulated

What history reveals about Forge River pollution on Long Island, New York's south shore.

Science.gov (United States)

Swanson, R Lawrence; Brownawell, B; Wilson, Robert E; O'Connell, Christine

2010-06-01

Fifty years ago, the Forge River and Moriches Bay, of Long Island's south shore lagoonal system, achieved notoriety when their polluted conditions were alluded to in a report of the US President's Science Advisory Committee (1965). The Woods Hole Oceanographic Institution investigated the bay throughout the 1950s, identifying duck farming as the cause of "objectionable", "highly contaminated" conditions of these waters. Much has changed: duck farming declined; the river was dredged to remove polluted sediments, improve navigation; and barrier island inlets stabilized. Yet, the river remains seasonally eutrophic. Why? This paper reviews what occurred in the Forge River watershed. While governments aggressively curtailed the impacts of duck pollution, they failed to manage development and sewage pollution. The Forge experience indicates that watershed management is a continuing governmental responsibility as development accelerates. Otherwise, we will always be looking for that instantaneous remediation that is usually not affordable and is socially contentious.

Open die forging of large shafts with porosity defects – physical and numerical modelling

DEFF Research Database (Denmark)

Christiansen, Peter; Hattel, Jesper Henri; Bay, Niels

2013-01-01

The aim and scope of this paper is centered to analyze the influence of the geometry of V-shaped dies on the closure of internal centerline porosity defects in ingots during multistep open-die forging. The investigation is performed with small scale physical models made from lead using V-shaped d......The aim and scope of this paper is centered to analyze the influence of the geometry of V-shaped dies on the closure of internal centerline porosity defects in ingots during multistep open-die forging. The investigation is performed with small scale physical models made from lead using V......-shaped dies with 90o and 120o and a reference pair of flat parallel platens. Holes drilled through the center of these preforms are produced to mimic centerline porosity in full scale cast ingots and intermediate rotation of the preforms replicate a multi-stage forging sequence under laboratory testing...

Multi-objective optimization of die geometry in ingot forging

DEFF Research Database (Denmark)

Christiansen, Peter; Martins, Paulo A.F.; Bay, Niels

2014-01-01

The soundness of an ingot after hot forging with different V-shaped lower dies is evaluated using finite element simulations.Two different modelling approaches that make use of uncoupled ductile damage and coupled ductile damage based on porousplasticity are employed. It is shown that the two...

Material Behavior Based Hybrid Process for Sheet Draw-Forging Thin Walled Magnesium Alloys

International Nuclear Information System (INIS)

Sheng, Z.Q.; Shivpuri, R.

2005-01-01

Magnesium alloys are conventionally formed at the elevated temperatures. The thermally improved formability is sensitive to the temperature and strain rate. Due to limitations in forming speeds, tooling strength and narrow processing windows, complex thin walled parts cannot be made by traditional warm drawing or hot forging processes. A hybrid process, which is based on the deformation mechanism of magnesium alloys at the elevated temperature, is proposed that combines warm drawing and hot forging modes to produce an aggressive geometry at acceptable forming speed. The process parameters, such as temperatures, forming speeds etc. are determined by the FEM modeling and simulation. Sensitivity analysis under the constraint of forming limits of Mg alloy sheet material and strength of tooling material is carried out. The proposed approach is demonstrated on a conical geometry with thin walls and with bottom features. Results show that designed geometry can be formed in about 8 seconds, this cannot be formed by conventional forging while around 1000s is required for warm drawing. This process is being further investigated through controlled experiments

The effects of thermomechanical history on the microstructure of a nickel-base superalloy during forging

Energy Technology Data Exchange (ETDEWEB)

Gardner, S., E-mail: 485354@swansea.ac.uk [College of Engineering, Bay Campus, Swansea University, Swansea SA1 8EN (United Kingdom); Li, W. [Rolls-Royce plc, PO Box 31, Derby DE24 8BJ (United Kingdom); Coleman, M. [College of Engineering, Bay Campus, Swansea University, Swansea SA1 8EN (United Kingdom); Johnston, R., E-mail: r.johnston@swansea.ac.uk [College of Engineering, Bay Campus, Swansea University, Swansea SA1 8EN (United Kingdom)

2016-06-21

The effect of thermo-mechanical history on hot compression behaviour and resulting microstructures of a nickel base superalloy is presented. Hot compression tests were carried out on HAYNES® 282® specimens to varying strains from 0.1 to 0.8. Both single pass and multi-pass tests were completed. 60 min inter-pass times were utilized to accurately replicate industrial forging practices. The effect of dynamic, metadynamic and static recrystallization during inter-pass times on flow stress was investigated. The resulting microstructures were analysed using scanning electron, optical microscopy and EBSD to relate grain size and homogeneity with flow stress data. The study showed a negligible difference between multi-pass and single pass tests for strain increments above 0.2. Therefore, when modelling similar low strain and strain rate forging processes in HAYNES® 282®, previous forging steps can be ignored.

A new Friction and Lubrication Test for Cold Forging

DEFF Research Database (Denmark)

Bay, Niels; Wibom, Ole; Aalborg Nielsen, J

1995-01-01

This paper presents a new friction and lubrication test for cold forging. The test allows controlled variation of the surface expansion in the range 0-2000%, the tool temperature in the range 20-270°C and the sliding length between 0 and infinite. Friction is decreasing with increasing temperature...

Age effects on cortical thickness in young Down's syndrome subjects: a cross-sectional gender study

International Nuclear Information System (INIS)

Romano, Andrea; Moraschi, Marta; Cornia, Riccardo; Stella, Giacomo; Bozzao, Alessandro; Gagliardo, Olga; Chiacchiararelli, Laura; Iani, Cristina; Albertini, Giorgio; Pierallini, Alberto

2015-01-01

The aim of this study was to determine differences in the characteristic pattern of age-related cortical thinning in men and women with Down's syndrome (DS) by means of MRI and automatic cortical thickness measurements and a cross-sectional design, in a large cohort of young subjects. Eighty-four subjects with DS, 30 females (11-35 years, mean age ± SD = 22.8 ± 5.9) and 54 males (11-35 years, mean age ± SD = 21.5 ± 6.5), were examined using a 1.5-T scanner. MRI-based quantification of cortical thickness was performed using FreeSurfer software package. For all subjects participating in the study, the Pearson product-moment correlation coefficient between age and mean cortical thickness values has been evaluated. A significant negative correlation between cortical thickness and age was found in female DS subjects, predominantly in frontal and parietal lobes, bilaterally. In male DS subjects, a significant negative correlation between cortical thickness and age was found in the right fronto-temporal lobes and cingulate regions. Whole brain mean cortical thickness values were significantly negative correlated with age only in female DS subjects. Females with Down's syndrome showed a strong correlation between cortical thickness and age, already in early age. We suggest that the cognitive impairment due to hormonal deficit in the postmenopausal period could be emphasized by the early structural decline of gray matter in female DS subjects. (orig.)

Age effects on cortical thickness in young Down's syndrome subjects: a cross-sectional gender study

Energy Technology Data Exchange (ETDEWEB)

Romano, Andrea; Moraschi, Marta [San Raffaele Foundation Rome, Rehabilitation Facility Ceglie Messapica, Rome (Italy); Cornia, Riccardo; Stella, Giacomo [University of Modena and Reggio Emilia, Department of Education and Human Sciences, Emilia-Romagna (Italy); Bozzao, Alessandro; Gagliardo, Olga [University Sapienza, NESMOS, Department of Neuroradiology, S. Andrea Hospital, Rome (Italy); Chiacchiararelli, Laura [University Sapienza, Department of Medical Physics, S. Andrea Hospital, Rome (Italy); Iani, Cristina [University of Modena and Reggio Emilia, Department of Communication and Economy, Emilia-Romagna (Italy); Albertini, Giorgio [IRCSS San Raffaele Pisana, Department of Paediatrics, Rome (Italy); Pierallini, Alberto [IRCSS San Raffaele Pisana, Department of Radiology, Rome (Italy)

2015-04-01

The aim of this study was to determine differences in the characteristic pattern of age-related cortical thinning in men and women with Down's syndrome (DS) by means of MRI and automatic cortical thickness measurements and a cross-sectional design, in a large cohort of young subjects. Eighty-four subjects with DS, 30 females (11-35 years, mean age ± SD = 22.8 ± 5.9) and 54 males (11-35 years, mean age ± SD = 21.5 ± 6.5), were examined using a 1.5-T scanner. MRI-based quantification of cortical thickness was performed using FreeSurfer software package. For all subjects participating in the study, the Pearson product-moment correlation coefficient between age and mean cortical thickness values has been evaluated. A significant negative correlation between cortical thickness and age was found in female DS subjects, predominantly in frontal and parietal lobes, bilaterally. In male DS subjects, a significant negative correlation between cortical thickness and age was found in the right fronto-temporal lobes and cingulate regions. Whole brain mean cortical thickness values were significantly negative correlated with age only in female DS subjects. Females with Down's syndrome showed a strong correlation between cortical thickness and age, already in early age. We suggest that the cognitive impairment due to hormonal deficit in the postmenopausal period could be emphasized by the early structural decline of gray matter in female DS subjects. (orig.)

Application of directional solidification ingot (LSD) in forging of PWR reactor vessel heads

International Nuclear Information System (INIS)

Benhamou, C.; Poitrault, I.

1985-09-01

Creusot-Loire Industrie uses this type of ingot for manufacture of Framatome 1300 and 1450 MW 4-loop PWR reactor vessel heads. This type of ingot offers a number advantages: improved internal soundness; greater chemical, structural and mechanical homogeneity of the finished part; simplified forging process. After a brief description of the pouring and solidification processes, this paper presents an analysis of the results of examinations performed on the prototype forging, as well as review of results obtained during industrial fabrication of dished heads from LSD ingots. The advantages of the LSD ingot over conventional ingots are discussed in conclusion

Effect of nonmetallic inclusions on anisotropy of ductility in 35KhN3MFA steel forgings

International Nuclear Information System (INIS)

Shtremel', M.A.; Yavojskij, V.I.; Volkov, V.A.; Chursin, G.M.; Chukhlov, V.I.; Fetisov, G.I.; Mochalin, N.K.; Smol'yaninov, L.V.

1980-01-01

Characteristics of nonmetaltic inclusions and anizotropy of ductility and of impuct strength of forgings of the 35KhN3MFA steel are compared at different variants of melting and outer-furnace treatment. It is shown that method of melting rugulates anisotropy of ductility primarily through deformability of large inclusions during forging. Deformability of inclusions considerably changes due to introduction of silicocalcium in iron mold [ru

Development of production technology and investigation of quality for forged-welded turbine rotors of steel 25Kh2NVFA

International Nuclear Information System (INIS)

Borisov, I.A.; Merinov, G.N.; Slezkina, E.V.

1997-01-01

A study was made into mechanical properties and microstructure of turbine rotor components manufactured by forging and heat treated under various conditions. It is revealed that the optimal heat treatment of forgings must include double quenching with subsequent tempering at 630-640 deg C for 10-20 h. Forged and welded rotors should be tempered at 620-630 deg C for 50-100 h. Microscopic examination and mechanical tests showed that low alloy steel 25Kh2NMF can be successfully used for manufacturing rotors of high-, medium-and low-heat turbines

Development of SiC Nanoparticles and Second Phases Synergistically Reinforced Mg-Based Composites Processed by Multi-Pass Forging with Varying Temperatures

Directory of Open Access Journals (Sweden)

Kaibo Nie

2018-01-01

Full Text Available In this study, SiC nanoparticles were added into matrix alloy through a combination of semisolid stirring and ultrasonic vibration while dynamic precipitation of second phases was obtained through multi-pass forging with varying temperatures. During single-pass forging of the present composite, as the deformation temperature increased, the extent of recrystallization increased, and grains were refined due to the inhibition effect of the increasing amount of dispersed SiC nanoparticles. A small amount of twins within the SiC nanoparticle dense zone could be found while the precipitated phases of Mg17Al12 in long strips and deformation bands with high density dislocations were formed in the particle sparse zone after single-pass forging at 350 °C. This indicated that the particle sparse zone was mainly deformed by dislocation slip while the nanoparticle dense zone may have been deformed by twinning. The yield strength and ultimate tensile strength of the composites were gradually enhanced through increasing the single-pass forging temperature from 300 °C to 400 °C, which demonstrated that initial high forging temperature contributed to the improvement of the mechanical properties. During multi-pass forging with varying temperatures, the grain size of the composite was gradually decreased while the grain size distribution tended to be uniform with reducing the deformation temperature and extending the forging passes. In addition, the amount of precipitated second phases was significantly increased compared with that after multi-pass forging under a constant temperature. The improvement in the yield strength of the developed composite was related to grain refinement strengthening and Orowan strengthening resulting from synergistical effect of the externally applied SiC nanoparticles and internally precipitated second phases.

Modelling the void deformation and closure by hot forging of ingot castings

DEFF Research Database (Denmark)

Christiansen, Peter; Hattel, Jesper Henri; Kotas, Petr

2012-01-01

by mechanical deformation. The aim of this paper is to analyze numerically if and to what degree the voids areclosed by the forging. Using the commercial simulation software ABAQUS, both simplified model ingots and physically manufactured ingots containing prescribed void distributions are deformed and analyzed....... The analysis concernsboth the void density change and the location of the voids in the part after deformation. The latter can be important for the subsequent reliability of the parts, for instance regarding fatigue properties. The analysis incorporates the Gurson yield criterion for metals containing voids...... and focuses on how the voids deform depending on their size and distribution in the ingot as well ashow the forging forces are applied....

Army Combat Medic Resilience: The Process of Forging Loyalty.

Science.gov (United States)

Abraham, Preetha A; Russell, Dale W; Huffman, Sarah; Deuster, Patricia; Gibbons, Susanne W

2018-03-01

This study presents a grounded theory analysis of in-depth interviews of United States Army Combat Medics (CMs) who had served in Iraq and/or Afghanistan. The study explores how 17 CMs nominated by their peers as resilient cope with military stressors in order to identify the factors that enable them to thrive amidst harsh conditions. Four distinct categories of characteristics unique to this group emerged: (1) social bonding, (2) readiness, (3) dual loyalty as performance, and (4) leader by example. Forging loyalty underpins these characteristics and represents the main process used by resilient CMs and comprised three behavior patterns: (1) commitment to the family, (2) commitment to the military mission, and (3) commitment to their guiding religious and spiritual beliefs. Prominent behavioral tendencies of forging loyalty likely developed during childhood and re-enforced by families, friends, and other role models. Based on the findings, new training and education efforts should focus on developing positive emotional, environmental, and social resources to enhance the health and well-being of service members and their families.

Effects of boron additions and solutionizing treatments on microstructures and ductility of forged Ti–6Al–4V alloys

International Nuclear Information System (INIS)

Luan, J.H.; Jiao, Z.B.; Chen, G.; Liu, C.T.

2015-01-01

Highlights: • Proper boron additions and heat-treatments improve the ductility of Ti64 alloys. • Coarse TiB precipitates embrittle the Ti64 alloys causing ductility loss. • Modified Ti64 forged alloys with high strength and high ductility are developed. - Abstract: The effects of boron additions on the microstructure and mechanical properties of forged Ti–6Al–4V alloys in different heat-treatment conditions have been characterized by both experimental studies and thermodynamic calculations. The results indicate a combination of proper post-forging treatments and B additions are helpful for control of the prior-β grain size and the volume fraction of α phase, thereby tuning the ductility of the forged Ti–6Al–4V alloys. However, the B-containing alloys exhibit a significant drop in ductility if the solutionizing temperature is too high, and this embrittlement is mainly due to the coarsening of brittle TiB borides. The mechanism in this case is due to the cleavage fracture of TiB rather than its debonding with the matrix, as indicated by the observation of the aligned TiB borides on the matching areas of both halves of the fracture surfaces. Thus, the TiB size and orientation, the prior-β grain size, and the volume fraction of the α phase all play important roles in controlling the mechanical properties of the forged Ti–6Al–4V alloys. The current findings shed light on the composition–microstructure–ductility relationship in the forged Ti–6Al–4V alloys

Effects of boron additions and solutionizing treatments on microstructures and ductility of forged Ti–6Al–4V alloys

Energy Technology Data Exchange (ETDEWEB)

Luan, J.H.; Jiao, Z.B. [Center for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, College of Science and Engineering, City University of Hong Kong, Hong Kong (China); Chen, G. [Engineering Research Center of Materials Behavior and Design, Ministry of Education, Nanjing University of Science and Technology, Nanjing 210094 (China); Liu, C.T., E-mail: chainliu@cityu.edu.hk [Center for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, College of Science and Engineering, City University of Hong Kong, Hong Kong (China)

2015-03-05

Highlights: • Proper boron additions and heat-treatments improve the ductility of Ti64 alloys. • Coarse TiB precipitates embrittle the Ti64 alloys causing ductility loss. • Modified Ti64 forged alloys with high strength and high ductility are developed. - Abstract: The effects of boron additions on the microstructure and mechanical properties of forged Ti–6Al–4V alloys in different heat-treatment conditions have been characterized by both experimental studies and thermodynamic calculations. The results indicate a combination of proper post-forging treatments and B additions are helpful for control of the prior-β grain size and the volume fraction of α phase, thereby tuning the ductility of the forged Ti–6Al–4V alloys. However, the B-containing alloys exhibit a significant drop in ductility if the solutionizing temperature is too high, and this embrittlement is mainly due to the coarsening of brittle TiB borides. The mechanism in this case is due to the cleavage fracture of TiB rather than its debonding with the matrix, as indicated by the observation of the aligned TiB borides on the matching areas of both halves of the fracture surfaces. Thus, the TiB size and orientation, the prior-β grain size, and the volume fraction of the α phase all play important roles in controlling the mechanical properties of the forged Ti–6Al–4V alloys. The current findings shed light on the composition–microstructure–ductility relationship in the forged Ti–6Al–4V alloys.

The development of reactor vessel internal heavy forging for 1000 MW pressurized-water reactor nuclear power plant

International Nuclear Information System (INIS)

Zhang Zhifeng; Chen Yongbo; Ding Xiuping; Zhang Lingfang

2012-01-01

This Paper introduced the development of Reactor Vessel Internal (RVI) heavy forgings for 1000 MW Pressurized Water Reactor (PWR) nuclear power plant, analyzed the manufacture difficulties and technical countermeasures. The testing result of the product indicated that the performance of RVI heavy forgings manufactured by Shanghai Heavy Machinery Plant Ld. (SHMP) is outstanding and entirely satisfy the technical requirements for RVI product. (authors)

Effect of technological parameters on formability of semi-solid rheological casting-forging 6061 alloy

Directory of Open Access Journals (Sweden)

Jianbo TAN

2016-02-01

Full Text Available The 6061 alloy cooling curve is determined by analysis software, and the 6061 semi-solid alloy is prepared by manual paddling process. The primary solid fraction is tested through prepared water quenched samples under different temperature. With H1F100 type servo press and cup type test mold, the forming of the 6061 semi-solid alloy rheological casting-forging is made. The influence of alloy temperature, forming pressure, upper mould temperature and holding time on the formability of 6061 alloy is researched. The results show that within the same set of mold completing casting and forging of the alloy is feasible. Along with the increase of the alloy temperature and the upper mould temperature, the formability of finished products becomes better. Under this experimentation, when the temperature of the semi-solid alloy is amongst 642 ℃ to 645 ℃ and the upper mould preheating temperature is amongst 200 ℃ to 300 ℃, casting defects such as cold insulation will form in the casting-forging sample of semi-solid 6061 alloy with the prolongation of holding time.

Residual stress in a thick section high strength T-butt weld

International Nuclear Information System (INIS)

Pearce, S.V.; Linton, V.M.; Oliver, E.C.

2008-01-01

Residual stresses in a structure are generated as a result of the various fabrication and welding processes used to make the component. Being able to quantify these residual stresses is a key step in determining the continuing integrity of a structure in service. In this work, the residual stresses around a high strength, quenched and tempered steel T-butt web to curved plate weld have been measured using neutron strain scanning. The results show that the residual stresses near the weld were dominated by the welding residual stresses, while the stresses further from the weld were dominated by the bending residual stresses. The results suggest that the combination of welding-induced residual stress and significant pre-welding residual stress, as in the case of a thick bent section of plate can significantly alter the residual stress profile from that in a flat plate

Multipass forging of Inconel 718 in the delta-Supersolvus domain: assessing and modeling microstructure evolution

Directory of Open Access Journals (Sweden)

Zouari Meriem

2014-01-01

Full Text Available This work is focused on the evolution of the microstructure of Inconel 718 during multi-pass forging processes. During the forming process, the material is subjected to several physical phenomena such as work-hardening, recovery, recrystallization and grain growth. In this work, transformation kinetics are modeled in the δ-Supersolvus domain (T>Tsolvus where the alloy is single-phase, all the alloying elements being dissolved into the FCC matrix. Torsion tests were used to simulate the forging process and recrystallization kinetics was modeled using a discontinuous dynamic recrystallization (DDRX two-site mean field model. The microstructure evolution under hot forging conditions is predicted in both dynamic and post-dynamic regimes based on the initial distribution of grain size and the evolution of dislocation density distribution during each step of the process. The model predicts recrystallization kinetics, recrystallized grain size distribution and stress–strain curve for different thermo-mechanical conditions and makes the connection between dynamic and post-dynamic regimes.

Effect of Friction on Barreling during cold Upset Forging of Aluminium 6082 Alloy Solid cylinders

Science.gov (United States)

Priyadarshini, Amrita; Kiran, C. P.; Suresh, K.

2018-03-01

Friction is one of the significant factors in forging operations since it affects metal flow in the die, forming load, strain distribution, tool and die life, surface quality of the product etc. In upset forging, the frictional forces at the die-workpiece interface oppose the outward flow of the material due to which the specimen develops a barrel shape. As a result, the deformation becomes non-uniform or inhomogeneous which is undesirable. Barreling can be reduced by applying effective lubricant on the surface of the platens. The objective of the present work is to study experimentally the effect of various frictional conditions (dry, grease, mineral oil) on barreling during upset forging of aluminum 6082 solid cylinders of different aspect ratio (length/diameter: 0.5, 0.75, 1). The friction coefficients are determined using the ring compression test. Curvature of barrel is determined based on the assumption that the curvature of the barrel follows the geometry of circular arc.

Effects of HIP and forging on fracture behaviour in cast iron with spheroidal vanadium carbides dispersed within martensitic-matrix microstructure

International Nuclear Information System (INIS)

Uematsu, Y.; Tokaji, K.; Nishigaki, K.; Okajima, D.; Ogasawara, M.

2010-01-01

The cast iron with spheroidal vanadium carbides dispersed within martensitic-matrix microstructure was developed as a die material due to its high hardness. In order to achieve high performances of dies, not only the hardness but also the mechanical properties such as fracture toughness and fatigue crack propagation (FCP) resistance should be improved. In this paper, hot isostatic pressing (HIP) or forging was applied to the cast iron to improve mechanical properties, and the fracture behaviour, such as flexural strength, fracture toughness and FCP, was studied. The average flexural strength was reduced by forging because of the enhanced notch sensitivity due to the increase in the hardness. The fracture toughness was not affected by HIP nor forging while its scatter was significantly reduced by both post-treatments. The intrinsic FCP resistance taking account of crack closure was the same regardless of the application of HIP or forging, indicating that a slight change in the microstructure resulting from both treatments and the presence of casting defects exerted little influence on FCP behaviour. It could be concluded that both HIP and forging could improve the hardness of the material, while fracture toughness and FCP resistance were maintained.

A multi-scale approach for high cycle anisotropic fatigue resistance: Application to forged components

International Nuclear Information System (INIS)

Milesi, M.; Chastel, Y.; Hachem, E.; Bernacki, M.; Loge, R.E.; Bouchard, P.O.

2010-01-01

Forged components exhibit good mechanical strength, particularly in terms of high cycle fatigue properties. This is due to the specific microstructure resulting from large plastic deformation as in a forging process. The goal of this study is to account for critical phenomena such as the anisotropy of the fatigue resistance in order to perform high cycle fatigue simulations on industrial forged components. Standard high cycle fatigue criteria usually give good results for isotropic behaviors but are not suitable for components with anisotropic features. The aim is to represent explicitly this anisotropy at a lower scale compared to the process scale and determined local coefficients needed to simulate a real case. We developed a multi-scale approach by considering the statistical morphology and mechanical characteristics of the microstructure to represent explicitly each element. From stochastic experimental data, realistic microstructures were reconstructed in order to perform high cycle fatigue simulations on it with different orientations. The meshing was improved by a local refinement of each interface and simulations were performed on each representative elementary volume. The local mechanical anisotropy is taken into account through the distribution of particles. Fatigue parameters identified at the microscale can then be used at the macroscale on the forged component. The linkage of these data and the process scale is the fiber vector and the deformation state, used to calculate global mechanical anisotropy. Numerical results reveal an expected behavior compared to experimental tendencies. We proved numerically the dependence of the anisotropy direction and the deformation state on the endurance limit evolution.

Environmentally Benign Lubricant Systems For Cold, Warm And Hot Forging

DEFF Research Database (Denmark)

Bay, Niels

2010-01-01

paper gives an overview of these efforts substituting environmentally hazardous lubricants in cold, warm and hot forging. The paper is an extract of the keynote paper [3] written by the author together with eight co-authors referring to collected papers and other information from more than 30 different...

High-resolution ice thickness and bed topography of a land-terminating section of the Greenland Ice Sheet

DEFF Research Database (Denmark)

Lindbäck, K.; Pettersson, R.; Doyle, S. H.

2014-01-01

We present ice thickness and bed topography maps with high spatial resolution (250 to 500 m) of a and-terminating section of the Greenland Ice Sheet derived from combined ground-based and airborne radar surveys. The data have a total area of ~12000 km2 and cover the whole ablation area of the out...

Development of a forging technology for the production of high-pressure compressor blades from γ-titanium aluminide. Project C: production of primary wrought material for the forging of turbine blades from gamma-TiAl and their microstructural optimization. Final report

International Nuclear Information System (INIS)

Appel, F.; Oehring, M.; Lorenz, U.; Wagner, R.

1999-01-01

By the development of a new canning technique which resulted in an effective thermal isolation of can and billet the flow stress mismatch of can and billet material could be minimized, which allowed crack-free and uniform extrusion. Using this technique which has been applied for patent hot extrusion is an effective and matured working method for ingot material. It allows to produce fine-grained and almost fully recrystallized material with increased workability as has been found by the determination of the forging window as well as by the successful forging of more than 200 compressor blades by the project partner Thyssen Umformtechnik. By forging under suited conditions also a microstructural homogenization is achieved in comparison to extruded material. (orig.)

A friction model for cold forging of aluminum, steel and stainless steel provided with conversion coating and solid film lubricant

DEFF Research Database (Denmark)

Bay, Niels; Eriksen, Morten; Tan, Xincai

2011-01-01

Adopting a simulative tribology test system for cold forging the friction stress for aluminum, steel and stainless steel provided with typical lubricants for cold forging has been determined for varying normal pressure, surface expansion, sliding length and tool/work piece interface temperature...

Structure and properties of large-sized forged disk of alloy type KhN73MBTYu-VD(EhI 698-VD)

International Nuclear Information System (INIS)

Sudakov, V.S.

1994-01-01

Investigation results are presented for structure and mechanical properties of serial large-sized forged disk 1100 mm in diameter produced of alloy type EhI 9698-VD hand tested after standard heat treatment and isothermal ageing at operating temperature. Chemical composition studies have revealed no macroheterogeneity. In a central cross-section macrostructure is free of pores, inclusions, delaminating and variation in grain size. The metal of the disk possesses high values of long-term rupture strength and creep resistance at 650-700 deg C

Developments of New Lubricants for Cold Forging of Stainless Steel

DEFF Research Database (Denmark)

Steenberg, Thomas; Christensen, Erik; Olesen, P.

1997-01-01

Two new lubricant systems for cold forging of stainless steel have been developed. The main component of these systems are FeCl3 and ZnCa2(PO4)2, respectively. Both lubricant systems have been tested using a backward extrusion test. The results show excellent lubricating properties with respect...

Cross section of α-induced reactions on iridium isotopes obtained from thick target yield measurement for the astrophysical γ process

Directory of Open Access Journals (Sweden)

T. Szücs

2018-01-01

Full Text Available The stellar reaction rates of radiative α-capture reactions on heavy isotopes are of crucial importance for the γ process network calculations. These rates are usually derived from statistical model calculations, which need to be validated, but the experimental database is very scarce. This paper presents the results of α-induced reaction cross section measurements on iridium isotopes carried out at first close to the astrophysically relevant energy region. Thick target yields of 191Ir(α,γ195Au, 191Ir(α,n194Au, 193Ir(α,n196mAu, 193Ir(α,n196Au reactions have been measured with the activation technique between Eα=13.4 MeV and 17 MeV. For the first time the thick target yield was determined with X-ray counting. This led to a previously unprecedented sensitivity. From the measured thick target yields, reaction cross sections are derived and compared with statistical model calculations. The recently suggested energy-dependent modification of the α+nucleus optical potential gives a good description of the experimental data.

Ageing of forged superaustenitic stainless steel: Precipitate phases and mechanical properties

Energy Technology Data Exchange (ETDEWEB)

Anburaj, J., E-mail: janburaj@gmail.com [Department of Metallurgical Engineering, PSG College of Technology, Coimbatore 641 004 (India); Nazirudeen, S.S. Mohamed; Narayanan, R.; Anandavel, B.; Chandrasekar, A. [Department of Metallurgical Engineering, PSG College of Technology, Coimbatore 641 004 (India)

2012-02-15

Highlights: Black-Right-Pointing-Pointer Solutionizing of 1250 Degree-Sign C and ageing of 500-1000 Degree-Sign C was done for hot forged SASS. Black-Right-Pointing-Pointer Strength and toughness increased by 25% on hot forged than the cast SASS. Black-Right-Pointing-Pointer Amounts of precipitates after ageing were evaluated by thermo-calc. Black-Right-Pointing-Pointer Sigma forms from chi at 900 Degree-Sign C and contains constant Cr and Mo contents, unlike chi. Black-Right-Pointing-Pointer Sigma is incoherent, contains high Mo and causes low toughness at 900 Degree-Sign C. - Abstract: Cast superaustenitic stainless steel (SASS), of composition 19 wt% Cr, 20 wt% Ni, 7.5 wt% Mo and 0.37 wt% N, is hot forged at 1200 Degree-Sign C. The forging was then solutionized at 1250 Degree-Sign C and aged for 1 h and 10 h at different temperatures in the range of 500-1000 Degree-Sign C. Effect of these treatments on (i) hardness and (ii) fracture toughness based on impact energy is reported. Chi is formed from low temperatures up to 800 Degree-Sign C, and sigma at temperatures above 900 Degree-Sign C. A model is proposed to illustrate the dissolution of chi and sigma in austenite at elevated temperatures. Compared with chi, sigma contains more Mo. Toughness decreased with increasing amounts of chi and sigma precipitates. However, in the temperature range of 850-950 Degree-Sign C, low toughness was observed for relatively a short ageing time, although virtually the volume of sigma phase is very low. This is attributed to the presence of incoherent sigma in austenite matrix. Fractographs of the impact-tested samples indicated an increased tendency for brittle fracture with increasing ageing temperatures (increase in sigma content). Thermodynamic calculations substantiated (i) EDS results of composition of secondary phases present in the aged SASS and (ii) the proposed model. From these studies it is concluded that sigma is enriched in Mo at 900 Degree-Sign C and can be as

Tensile properties of a dual-axial forged Ti–Fe–Cu alloy containing boron

Energy Technology Data Exchange (ETDEWEB)

Zadorozhnyy, V.Yu., E-mail: zadorozhnyyvlad@gmail.com [National University of Science and Technology “MISIS”, Leninsky prospect, 4, Moscow 119049 (Russian Federation); Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan); Shchetinin, I.V.; Chirikov, N.V. [National University of Science and Technology “MISIS”, Leninsky prospect, 4, Moscow 119049 (Russian Federation); Louzguine-Luzgin, D.V. [WPI Advanced Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan)

2014-09-22

In the present work we introduce a micro/nano-structured α+β Ti-based low-alloy produced by the tilt-casting method and subjected to subsequent thermo-mechanical treatment. After hot dual-axial forging at 900 °C, subsequent heating at 700 °C and water quenching a Ti{sub 94}Fe{sub 3}Cu{sub 3}+1000 ppm of boron alloy, containing inexpensive alloying elements, showed an ultimate tensile strength value of about 950 MPa and percentage elongation of about 5.2%. It is shown that the intensive forging treatment and subsequent heat treatment are leading to significantly improved mechanical properties of such an alloy compared to the as-cast state.

Qualification of laser based additive production for manufacturing of forging Tools

Directory of Open Access Journals (Sweden)

Junker Daniel

2015-01-01

Full Text Available Mass customization leads to very short product life cycles, so the costs of a tool have to be amortized with a low number of workpieces. Especially for highly loaded tools, like those for forging, that leads to expensive products. Therefore more economical production processes for tool manufacturing have to be investigated. As laser additive manufacturing is already used for the production of moulds for injection moulding, this technology maybe could also improve the forging tool production. Within this paper laser metal deposition, which is industrially used for tool repair, will be investigated for the use in tool manufacturing. Therefore a mechanical characterization of parts built with different laser process parameters out of the hot work tool steel 1.2709 is made by upsetting tests and hardness measurements. So the influence of the additive manufacturing process on the hardness distribution is analysed.

The coarsening effect of SA508-3 steel used as heavy forgings material

Directory of Open Access Journals (Sweden)

Dingqian Dong

2015-01-01

Full Text Available SA508Gr.3 steel is popularly used to produce core unit of nuclear power reactors due to its outstanding ability of anti-neutron irradiation and good fracture toughness. The forging process takes important role in manufacturing to refine the grain size and improve the material properties. But due to their huge size, heavy forgings cannot be cooled down quickly, and the refined grains usually have long time to grow in high temperature conditions. If the forging process is not adequately scheduled or implemented, very large grains up to millimetres in size may be found in this steel and cannot be eliminated in the subsequent heat treatment. To fix the condition which may causes the coarsening of the steel, hot upsetting experiments in the industrial production environment were performed under different working conditions and the corresponding grain sizes were measured and analysed. The observation showed that the grain will abnormally grow if the deformation is less than a critical value. The strain energy takes a critical role in the grain evolution. If dynamic recrystallization consumes the strain energy as much as possible, the normal grains will be obtained. While if not, the stored strain energy will promote abnormal growth of the grains.

Wear Improvement of Tools in the Cold Forging Process for Long Hex Flange Nuts.

Science.gov (United States)

Hsia, Shao-Yi; Shih, Po-Yueh

2015-09-25

Cold forging has played a critical role in fasteners and has been widely used in automotive production, manufacturing, aviation and 3C (Computer, Communication, and Consumer electronics). Despite its extensive use in fastener forming and die design, operator experience and trial and error make it subjective and unreliable owing to the difficulty of controlling the development schedule. This study used finite element analysis to establish and simulate wear in automotive repair fastener manufacturing dies based on actual process conditions. The places on a die that wore most quickly were forecast, with the stress levels obtained being substituted into the Archard equation to calculate die wear. A 19.87% improvement in wear optimization occurred by applying the Taguchi quality method to the new design. Additionally, a comparison of actual manufacturing data to simulations revealed a nut forging size error within 2%, thereby demonstrating the accuracy of this theoretical analysis. Finally, SEM micrographs of the worn surfaces on the upper punch indicate that the primary wear mechanism on the cold forging die for long hex flange nuts was adhesive wear. The results can simplify the development schedule, reduce the number of trials and further enhance production quality and die life.

76 FR 8773 - Forged Stainless Steel Flanges From India and Taiwan

Science.gov (United States)

2011-02-15

... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 731-TA-639 and 640 (Third Review)] Forged Stainless Steel Flanges From India and Taiwan AGENCY: United States International Trade Commission. ACTION... Taiwan would be likely to lead to continuation or recurrence of material injury. On January 31, 2011, the...

A Probabilistic Analysis of the Nxt Forging Algorithm

Directory of Open Access Journals (Sweden)

Serguei Popov

2016-12-01

Full Text Available We discuss the forging algorithm of Nxt from a probabilistic point of view, and obtain explicit formulas and estimates for several important quantities, such as the probability that an account generates a block, the length of the longest sequence of consecutive blocks generated by one account, and the probability that one concurrent blockchain wins over an- other one. Also, we discuss some attack vectors related to splitting an account into many smaller ones.

Forging of cast Mg-3Sn-2Ca-0.4Al-0.4Si magnesium alloy using processing map

International Nuclear Information System (INIS)

Rao, K. P.; Suresh, K.; Prasad, Y. V. R. K.; Hort, N.; Kainer, K. U.

2016-01-01

Mg-3Sn-2Ca (TX32) alloy has good creep resistance but limited workability. Minor amounts of Al and Si have been added to TX32 for improving its hot workability. The processing map for the TX32-0.4Al-0.4Si alloy exhibited two workability domains in the temperature and strain rate ranges: (1) 310-415.deg.C/0.0003-0.003 s-1 and (2) 430-500.deg.C/0.003-3 s-1. The alloy exhibited flow instability at temperatures < 350.deg.C at strain rates > 0.01 s-1. The alloy has been forged to produce a cup shape component to validate these findings of processing map. Finite-element (FE) simulation has been performed for obtaining the local variations of strain and strain rate within the forging. The microstructures of the forged components under the optimal domain conditions revealed dynamically recrystallized grains, and those forged in the flow instability regime have fractured and exhibited flow localization bands and cracks. The experimental load stroke curves correlated well with those obtained by FE simulation.

Forging of cast Mg-3Sn-2Ca-0.4Al-0.4Si magnesium alloy using processing map

Energy Technology Data Exchange (ETDEWEB)

Rao, K. P.; Suresh, K.; Prasad, Y. V. R. K. [University of Hong Kong, Hong Kong (China); Hort, N.; Kainer, K. U. [Magnesium Innovation Centre, Geesthacht (Germany)

2016-06-15

Mg-3Sn-2Ca (TX32) alloy has good creep resistance but limited workability. Minor amounts of Al and Si have been added to TX32 for improving its hot workability. The processing map for the TX32-0.4Al-0.4Si alloy exhibited two workability domains in the temperature and strain rate ranges: (1) 310-415.deg.C/0.0003-0.003 s-1 and (2) 430-500.deg.C/0.003-3 s-1. The alloy exhibited flow instability at temperatures < 350.deg.C at strain rates > 0.01 s-1. The alloy has been forged to produce a cup shape component to validate these findings of processing map. Finite-element (FE) simulation has been performed for obtaining the local variations of strain and strain rate within the forging. The microstructures of the forged components under the optimal domain conditions revealed dynamically recrystallized grains, and those forged in the flow instability regime have fractured and exhibited flow localization bands and cracks. The experimental load stroke curves correlated well with those obtained by FE simulation.

The Simulation and Analysis of the Closed Die Hot Forging Process by A Computer Simulation Method

Directory of Open Access Journals (Sweden)

Dipakkumar Gohil

2012-06-01

Full Text Available The objective of this research work is to study the variation of various parameters such as stress, strain, temperature, force, etc. during the closed die hot forging process. A computer simulation modeling approach has been adopted to transform the theoretical aspects in to a computer algorithm which would be used to simulate and analyze the closed die hot forging process. For the purpose of process study, the entire deformation process has been divided in to finite number of steps appropriately and then the output values have been computed at each deformation step. The results of simulation have been graphically represented and suitable corrective measures are also recommended, if the simulation results do not agree with the theoretical values. This computer simulation approach would significantly improve the productivity and reduce the energy consumption of the overall process for the components which are manufactured by the closed die forging process and contribute towards the efforts in reducing the global warming.

Forging Consensus for Implementing Youth Socialization Policy in Northwest China

Science.gov (United States)

Fairbrother, Gregory P.

2011-01-01

The goal of this article is to examine how the provincial education media in China play a role of forging consensus among local actors responsible for the implementation of new centrally-promulgated youth socialization policy. In doing so, it also explores the tension among three of the Chinese state's claims to legitimacy: economic development,…

Through thickness property variations in a thick plate AA7050 friction stir welded joint

International Nuclear Information System (INIS)

Canaday, Clinton T.; Moore, Matthew A.; Tang, Wei; Reynolds, A.P.

2013-01-01

In this study, moderately thick (32 mm) AA7050 plates were joined by friction stir welding (FSW). Various methods were used to characterize the welded joints, including nugget grain size measurements at different locations through the thickness, micro-hardness indentation through nugget, thermo-mechanically affected zone (TMAZ), and heat affected zone (HAZ) at different cross section heights, and residual stress measurement using the cut compliance method with full thickness and partial thickness specimens. All testing results are consistent with the presence of a strong gradient in peak temperature through the plate thickness during FSW.

Large forging manufacturing process

Science.gov (United States)

Thamboo, Samuel V.; Yang, Ling

2002-01-01

A process for forging large components of Alloy 718 material so that the components do not exhibit abnormal grain growth includes the steps of: a) providing a billet with an average grain size between ASTM 0 and ASTM 3; b) heating the billet to a temperature of between 1750.degree. F. and 1800.degree. F.; c) upsetting the billet to obtain a component part with a minimum strain of 0.125 in at least selected areas of the part; d) reheating the component part to a temperature between 1750.degree. F. and 1800.degree. F.; e) upsetting the component part to a final configuration such that said selected areas receive no strains between 0.01 and 0.125; f) solution treating the component part at a temperature of between 1725.degree. F. and 1750.degree. F.; and g) aging the component part over predetermined times at different temperatures. A modified process achieves abnormal grain growth in selected areas of a component where desirable.

The influence of quench sensitivity on residual stresses in the aluminium alloys 7010 and 7075

International Nuclear Information System (INIS)

Robinson, J.S.; Tanner, D.A.; Truman, C.E.; Paradowska, A.M.; Wimpory, R.C.

2012-01-01

The most critical stage in the heat treatment of high strength aluminium alloys is the rapid cooling necessary to form a supersaturated solid solution. A disadvantage of quenching is that the thermal gradients can be sufficient to cause inhomogeneous plastic deformation which in turn leads to the development of large residual stresses. Two 215 mm thick rectilinear forgings have been made from 7000 series alloys with widely different quench sensitivity to determine if solute loss in the form of precipitation during quenching can significantly affect residual stress magnitudes. The forgings were heat treated and immersion quenched using cold water to produce large magnitude residual stresses. The through thickness residual stresses were measured by neutron diffraction and incremental deep hole drilling. The distribution of residual stresses was found to be similar for both alloys varying from highly triaxial and tensile in the interior, to a state of biaxial compression in the surface. The 7010 forging exhibited larger tensile stresses in the interior. The microstructural variation from surface to centre for both forgings was determined using optical and transmission electron microscopy. These observations were used to confirm the origin of the hardness variation measured through the forging thickness. When the microstructural changes were accounted for in the through thickness lattice parameter, the residual stresses in the two forgings were found to be very similar. Solute loss in the 7075 forging appeared to have no significant effect on the residual stress magnitudes when compared to 7010. - Highlights: ► Through thickness residual stress measurements made on large Al alloy forgings. ► Residual stress characterised using neutron diffraction and deep hole drilling. ► Biaxial compressive surface and triaxial subsurface residual stresses. ► Quench sensitivity of 7075 promotes significant microstructural differences to 7010. ► When precipitation is

Shape and dimensions of cardiac chambers: Importance of CT section thickness and orientation

International Nuclear Information System (INIS)

Hoffman, E.A.; Ritman, E.L.

1985-01-01

Three-dimensional (3D) computed tomography (CT) scan data were used to quantitate the geometry of all heart chambers. The Dynamic Spatial Reconstructor (DSR) was used to scan dogs with in situ casts of the cardiac chambers. Chamber volumes estimated from DSR images were accurate within 5% of water displacement volume measurements of the actual casts for chambers greater than 11 ml and within 10% of water displacement volumes for chambers less than 11 ml. Anatomic features of the actual cast correlated closely with anatomy visible in computer-generated surface images of the 3D DSR image data. The important effect of reconstructed section thickness and orientation on the fidelity of 3D cardiac geometry is demonstrated

Fatigue properties of high-strength materials used in cold-forging tools

DEFF Research Database (Denmark)

Brøndsted, P.; Skov-Hansen, P.

1998-01-01

In the present work classical analytical models are used to describe the static stress–strain curves, low-cycle fatigue properties and fatigue crack growth behaviour of high-strength materials for use in tools for metal-forming processes such as cold forging and extrusion. The paper describes the...

Developments of steel fabrication processes for castings and ingots for forgings

International Nuclear Information System (INIS)

Fernandez, S.

1980-01-01

This chapter deals with a series of technological developments in the manufacture of steels which have occurred during the last years, in particular reporting the results obtained in Reinosa with some of these methods in the fabrication of castings as well as forgings and rolled products. (author)

75 FR 67110 - Forged Stainless Steel Flanges From India and Taiwan

Science.gov (United States)

2010-11-01

... Stainless Steel Flanges From India and Taiwan AGENCY: United States International Trade Commission. ACTION... India and Taiwan. SUMMARY: The Commission hereby gives notice that it has instituted reviews pursuant to... the antidumping duty orders on forged stainless steel flanges from India and Taiwan would be likely to...

X-ray tomography studies on porosity and particle size distribution in cast in-situ Al-Cu-TiB{sub 2} semi-solid forged composites

Energy Technology Data Exchange (ETDEWEB)

Mathew, James; Mandal, Animesh [School of Minerals, Metallurgical and Materials Engineering, Indian Institute of Technology, Bhubaneswar (India); Warnett, Jason; Williams, Mark A. [WMG, University of Warwick, Coventry CV4 7AL (United Kingdom); Chakraborty, Madhusudan [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur (India); Srirangam, Prakash, E-mail: p.srirangam@warwick.ac.uk [WMG, University of Warwick, Coventry CV4 7AL (United Kingdom)

2016-08-15

X-ray computed tomography (XCT) was used to characterise the internal microstructure and clustering behaviour of TiB{sub 2} particles in in-situ processed Al-Cu metal matrix composites prepared by casting method. Forging was used in semi-solid state to reduce the porosity and to uniformly disperse TiB{sub 2} particles in the composite. Quantification of porosity and clustering of TiB{sub 2} particles was evaluated for different forging reductions (30% and 50% reductions) and compared with an as-cast sample using XCT. Results show that the porosity content was decreased by about 40% due to semi-solid forging as compared to the as-cast condition. Further, XCT results show that the 30% forging reduction resulted in greater uniformity in distribution of TiB{sub 2} particles within the composite compared to as-cast and the 50% forge reduction in semi-solid state. These results show that the application of forging in semi-solid state enhances particle distribution and reduces porosity formation in cast in-situ Al-Cu-TiB{sub 2} metal matrix composites. - Highlights: •XCT was used to visualise 3D internal structure of Al-Cu-TiB{sub 2} MMCs. •Al-Cu-TiB{sub 2} MMC was prepared by casting using flux assisted synthesis method. •TiB{sub 2} particles and porosity size distribution were evaluated. •Results show that forging in semi-solid condition decreases the porosity content and improve the particle dispersion in MMCs.

Medium carbon vanadium steels for closed die forging; Acos de medio carbono microligados ao vanadio para forjaria em matriz fechada

Energy Technology Data Exchange (ETDEWEB)

Jeszensky, Gabor; Plaut, Ronald Lesley

1994-12-31

This work analyses the medium carbon micro alloyed vanadium potential for closed die forged production. The steels reach the mechanical resistance requests during cooling after forging, eliminating the subsequent thermal treatment. Those steels also present good fatigue resistance and machinability. The industrial scale experiments are also reported 16 refs., 21 figs.

A coupled thermo-mechanical pseudo inverse approach for preform design in forging

Science.gov (United States)

Thomas, Anoop Ebey; Abbes, Boussad; Li, Yu Ming; Abbes, Fazilay; Guo, Ying-Qiao; Duval, Jean-Louis

2017-10-01

Hot forging is a process used to form difficult to form materials as well as to achieve complex geometries. This is possible due to the reduction of yield stress at high temperatures and a subsequent increase in formability. Numerical methods have been used to predict the material yield and the stress/strain states of the final product. Pseudo Inverse Approach (PIA) developed in the context of cold forming provides a quick estimate of the stress and strain fields in the final product for a given initial shape. In this paper, PIA is extended to include the thermal effects on the forging process. A Johnson-Cook thermo-viscoplastic material law is considered and a staggered scheme is employed for the coupling between the mechanical and thermal problems. The results are compared with available commercial codes to show the efficiency and the limitations of PIA.

Optimum back-pressure forging using servo die cushion

OpenAIRE

Kawamoto, Kiichiro; Yoneyama, Takeshi; Okada, Masato; Kitayama, Satoshi; Chikahisa, Junpei

2014-01-01

This study focused on utilizing a servo die cushion (in conjunction with a servo press) as a "back-pressure load generator," to determine its effect on shape accuracy of the formed part and total forming load in forward extrusion during cold forging. The effect of back-pressure load application was confirmed in experiments, and the optimum setting pattern of back-pressure load was considered to minimize both shape accuracy of the formed part and back-pressure energy, which was representative ...

Fatigue behavior of rolled and forged tungsten at 25°, 280° and 480 °C

International Nuclear Information System (INIS)

Habainy, J.; Iyengar, S.; Lee, Y.; Dai, Y.

2015-01-01

Pure tungsten has been chosen as the target material at the European Spallation Source facility in Lund. Calculations show that the target temperature can reach 500 °C momentarily during the spallation process, leading to thermal fatigue. Target life estimations require fatigue data at different temperatures and this work focuses on generating such data for pure, unirradiated, rolled and forged tungsten in the range 25°–480 °C. For specimens oriented in the rolling direction, tensile tests at room temperature indicated Young's modulus values in the range 320–390 GPa, low levels of plasticity (<0.23%) and UTS values in the range 397 MPa (unpolished) and 705 MPa (Polished). UTS for forged specimens were around 500 MPa. Stress-controlled fatigue tests were conducted in the tensile regime, with a runout limit of 2 × 10"6 cycles. At 25 °C, unpolished specimens had fatigue limits of 150 MPa (rolling and transverse direction), and 175 MPa (forged). For polished specimens in the rolling direction, fatigue limits were higher at 237.5 MPa (25 °C) and 252.5 MPa (280 °C). The forged specimens showed slightly better fatigue properties and marginal cyclic hardening at 480 °C. - Highlights: • Stress & strain-controlled fatigue tests on pure tungsten at 25°, 280° & 480 °C. • Unirradiated, rolled and forged specimens in polished and unpolished condition. • Min. tensile strength (MPa): 397 (25 °C), 472 (280 °C) and 363 (480 °C). • Min. endurance limit (MPa): 137.5 (25 °C), 250 (280 °C) and 150 (480 °C). • Marginal cyclic hardening observed at 480 °C.

Development of a novel cold forging process to manufacture eccentric shafts

Science.gov (United States)

Pasler, Lukas; Liewald, Mathias

2018-05-01

Since the commercial usage of compact combustion engines, eccentric shafts have been used to transform translational into rotational motion. Over the years, several processes to manufacture these eccentric shafts or crankshafts have been developed. Especially for single-cylinder engines manufactured in small quantities, built crankshafts disclose advantages regarding tooling costs and performance. Those manufacturing processes do have one thing in common: They are all executed at elevated temperatures to enable the material to be formed to high forming degree. In this paper, a newly developed cold forging process is presented, which combines lateral extrusion and shifting for manufacturing a crank in one forming operation at room temperature. In comparison to the established upsetting and shifting methods to manufacture such components, the tool cavity or crank web thickness remains constant. Therefore, the developed new process presented in this paper consists of a combination of shifting and extrusion of the billet, which allows pushing material into the forming zone during shifting. In order to reduce the tensile stresses induced by the shifting process, compressive stresses are superimposed. It is expected that the process limits will be expanded regarding the horizontal displacement and form filling. In the following report, the simulation and design of the tooling concept are presented. Experiments were conducted and compared with corresponding simulation results afterwards.

Hot Deformation Behavior and Pulse Current Auxiliary Isothermal Forging of Hot Pressing Sintering TiAl Based Alloys.

Science.gov (United States)

Shi, Chengcheng; Jiang, Shaosong; Zhang, Kaifeng

2017-12-16

This paper focuses on the fabrication of as-forged Ti46.5Al2Cr1.8Nb-(W, B) alloy via pulse current auxiliary isothermal forging (PCIF). The starting material composed of near gamma (NG) microstructure was fabricated by adopting pre-alloyed powders via hot pressing sintering (HPS) at 1300 °C. Isothermal compression tests were conducted at a strain rate range of 0.001-0.1 s -1 and a temperature range of 1125-1275 °C to establish the constitutive model and processing map. The optimal hot deformation parameters were successfully determined (in a strain rate range of 10 -3 -2.5 × 10 -3 s -1 and temperature range of 1130-1180 °C) based on the hot processing map and microstructure observation. Accordingly, an as-forged TiAl based alloy without cracks was successfully fabricated by PCIF processing at 1175 °C with a nominal strain rate of 10 -3 s -1 . Microstructure observation indicated that complete dynamic recrystallization (DRX) and phase transformation of γ→α₂ occurred during the PCIF process. The elongation of as-forged alloy was 136%, possessing a good secondary hot workability, while the sintered alloy was only 66% when tested at 900 °C with a strain rate of 2 × 10 -4 s -1 .

Evolution of the Ultrasonic Inspection of Heavy Rotor Forgings Over the Last Decades

Science.gov (United States)

Zimmer, A.; Vrana, J.; Meiser, J.; Maximini, W.; Blaes, N.

2010-02-01

All types of heavy forgings that are used in energy machine industry, rotor shafts as well as discs, retaining rings or tie bolts are subject to extensive nondestructive inspections before they are delivered to the customer. Due to the availability of the parts in simple shapes, these forgings are very well suited for full volmetric inspections using ultrasound. In the beginning, these inspections were carried out manually, using straight beam probes and analogue equipment. Higher requirements in reliability, efficiency, safety and power output in the machines have lead to higher requirements for the ultrasonic inspection in the form of more scanning directions, higher sensitivity demands and improved documentation means. This and the increasing use of high alloy materials for ever growing parts, increase the need for more and more sophisticated methods for testing the forgings. Angle scans and sizing technologies like DGS have been implemented, and for more than 15 years now, mechanized and automated inspections have gained importance since they allow better documentation as well as easier evaluation of the recorded data using different views (B- C- or D-Scans), projections or tomography views. The latest major development has been the availability of phased array probes to increase the flexibility of the inspection systems. Many results of the ongoing research in ultrasonic's have not been implemented yet. Today's availability of fast computers, large and fast data storages allows saving RF inspection data and applying sophisticated signal processing methods. For example linear diffraction tomography methods like SAFT offer tools for 3D reconstruction of inspection data, simplifying sizing and locating of defects as well as for improving signal to noise ratios. While such methods are already applied in medical ultrasonic's, they are still to be implemented in the steel industry. This paper describes the development of the ultrasonic inspection of heavy forgings

Characterization of residual stresses in heat treated Ti-6Al-4V forgings by machining induced distortion

Directory of Open Access Journals (Sweden)

Werner E.

2010-06-01

Full Text Available To provide a solid base for improved material exploitation in dimensioning calculations it is necessary to determine the stress state in the part prior to service loading. In order to achieve higher material strength at elevated temperatures, the surface temperature gradient with respect to time has to be sufficiently high during heat treatment. This results in non-negligable residual stresses that can reduce the allowable load level upon which yielding occurs. For titanium alloys there are two common heat treatments, namely solution treatment and mill annealing. The latter one is the method of choice within the presented project. Mill annealing is utilized in order to significantly reduce the residual stresses in the parts without loosing much of the improved strength at elevated temperatures. Quantification of residual stresses is done by solving an inverse problem. From the measurement of distortion, induced by dividing the investigated part, the residual stress state can be calculated via analytical modeling or correlation with finite element models. To assure a minimum perturbation of the residual stress state during specimen production, dividing of the part is accomplished by electric discharge machining. The parts of interest are v-shaped prisms with a length of approximatly 450 mm and a thickness in the cross sectional area from about 20 mm to 45 mm. Figure 1(a shows the forged part and 1(b the dimensions of the cross section in millimeters as well as the material properties considered in the finite element model. The heat exchange between the part and the environment is modelled as heat transfer by convection superimposed with heat radiation. Since the parts are exposed to air during forging and heat treatment, the surface develops a strongly adhesive oxide layer, the so called alpha-case. After forging the parts are cooled in air and heat treated at a temperature of 720° C for a duration of 120 min. Subsequent air cooling and

Quick Reaction Evaluation of Materials and Processes (QRE). Task Order 0008: Titanium Billet Characterization and Materials Properties Development (Nonconforming Titanium) - Executive Summary

Science.gov (United States)

2012-01-01

using Avesta Pickling Paste 101 to determine forging flowlines. No anomalous microstructure was noticed during this examination. This 4”(w) x 45”(l...face of this section through the thickness was machined to a 32 RA surface finish and macro-etched using Avesta Pickling Paste 101 to determine

Engine piston assembly and forged piston member therefor having a cooling recess

Energy Technology Data Exchange (ETDEWEB)

Cooper, B.C.; Erickson, K.L.; Green, J.A.; Nyez, D.S.

1989-09-19

This patent describes a forged steel piston member for reciprocating movement in an engine. It comprises: an upper portion of substantially cylindrical shape and having a central axis, a top surface, a tubular wall depending from the top surface and having a peripheral groove adapted to receive a sealing ring, a lower end surface, and an inwardly facing wall surface extending upwardly from the lower end surface. The upper portion further includes an outwardly facing wall surface spaced radially inwardly from the inwardly facing wall surface and a downwardly facing transition portion blendingly associated with the inwardly and outwardly facing wall surfaces to collectively define an annular cooling recess, the transition portion being elevational spaced a relatively short distance from the top surface; and the inwardly facing wall surface being a machined surface of revolution about the central axis integral or one-piece forging.

FE-simulation of hot forging with an integrated heat treatment with the objective of residual stress prediction

Science.gov (United States)

Behrens, Bernd-Arno; Chugreeva, Anna; Chugreev, Alexander

2018-05-01

Hot forming as a coupled thermo-mechanical process comprises numerous material phenomena with a corresponding impact on the material behavior during and after the forming process as well as on the final component performance. In this context, a realistic FE-simulation requires reliable mathematical models as well as detailed thermo-mechanical material data. This paper presents experimental and numerical results focused on the FE-based simulation of a hot forging process with a subsequent heat treatment step aiming at the prediction of the final mechanical properties and residual stress state in the forged component made of low alloy CrMo-steel DIN 42CrMo4. For this purpose, hot forging experiments of connecting rod geometry with a corresponding metallographic analysis and x-ray residual stress measurements have been carried out. For the coupled thermo-mechanical-metallurgical FE-simulations, a special user-defined material model based on the additive strain decomposition method and implemented in Simufact Forming via MSC.Marc solver features has been used.

Study on antioxidant experiment on forged steel tube sheet and tube hole for steam generator

International Nuclear Information System (INIS)

Zong Hai; Wang Detai; Ding Yang

2012-01-01

Antioxidant experiment on forged steel tube sheet and tube hole for steam generator was studied and the influence of different simulated heat treatments on the antioxidant performance of tube sheet and tube hole was made. The influence of different antioxidant methods on the size of tube hole was drawn. Furthermore, the change of size and weight of 18MnD5 forged steel tube sheet on the condition of different simulated heat treatments was also studied. The analytical results have proved reference information for the use of 18MnD5 material and for key processes of processing tube hole and wearing and expanding U-style tube. (authors)

Social Work and Engineering Collaboration: Forging Innovative Global Community Development Education

Science.gov (United States)

Gilbert, Dorie J.

2014-01-01

Interdisciplinary programs in schools of social work are growing in scope and number. This article reports on collaboration between a school of social work and a school of engineering, which is forging a new area of interdisciplinary education. The program engages social work students working alongside engineering students in a team approach to…

Forgings made of austenitic chromium-nickel steels for the low temperature range

International Nuclear Information System (INIS)

Gruendler, O.; Schwarz, W.; Koren, M.

1981-01-01

The authors discuss the low temperature application of austenitic chromium-nickel steels for energy production and process techniques. Material requirements are presented, and the behaviour, mechanical and physical properties of such steels are discussed. The manufacture of forgings is considered and test results presented. (Auth.)

Forgings made of austenitic chromium-nickel steels for the low temperature range

Energy Technology Data Exchange (ETDEWEB)

Gruendler, O.; Schwarz, W.; Koren, M. (Vereinigte Edelstahlwerke A.G. (VEW), Kapfenberg (Austria))

1981-09-01

The authors discuss the low temperature application of austenitic chromium-nickel steels for energy production and process techniques. Material requirements are presented, and the behaviour, mechanical and physical properties of such steels are discussed. The manufacture of forgings is considered and test results presented.

Fatigue and fracture behavior of low alloy ferritic forged steels

International Nuclear Information System (INIS)

Chaudhry, V.; Sharma, A.K.; Muktibodh, U.C.; Borwankar, Neeraj; Singh, D.K.; Srinivasan, K.N.; Kulkarni, R.G.

2016-01-01

Low alloy ferritic steels are widely used in nuclear industry for the construction of pressure vessels. Pressure vessel forged low alloy steels 20MnMoNi55 (modified) have been developed indigenously. Experiments have been carried out to study the Low Cycle Fatigue (LCF) and fracture behavior of these forged steels. Fully reversed strain controlled LCF testing at room temperature and at 350 °C has been carried out at a constant strain rate, and for different axial strain amplitude levels. LCF material behavior has been studied from cyclic stress-strain responses and the strain-life relationships. Fracture behavior of the steel has been studied based on tests carried out for crack growth rate and fracture toughness (J-R curve). Further, responses of fatigue crack growth rate tests have been compared with the rate evaluated from fatigue precracking carried out for fracture toughness (J-R) tests. Fractography of the samples have been carried out to reveal dominant damage mechanisms in crack propagation and fracture. The fatigue and fracture properties of indigenously developed low alloy steel 20MnMoNi55 (modified) steels are comparable with similar class of steels. (author)

Effect of precipitates on microstructures and properties of forged Mg-10Gd-2Y-0.5Zn-0.3Zr alloy during ageing process

International Nuclear Information System (INIS)

Han, X.Z.; Xu, W.C.; Shan, D.B.

2011-01-01

Highlights: · The effect of forging process on microstructure evolution and mechanical properties of Magnesium alloy with rare earth was investigated. · The optimal mechanical properties of the alloy with high strength and enough elongation were obtained after forging and ageing process. · The strength improvement of the alloy after forging and ageing process mainly results from the precipitation of 14H-type LPSO phase. · Strengthening mechanism of the alloy is controlled by the precipitation of β' and 14H-type LPSO phases which can inhibit sliding of dislocations and growth of grain boundaries. - Abstract: The precipitate behavior during forging and ageing process of Mg-10Gd-2Y-0.5Zn-0.3Zr alloy has been investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The mechanical properties of the alloy after forging and ageing process have been evaluated using Vickers hardness and room-temperature tensile tests. The results show that precipitation of 14H-type long period stacking order (LPSO) phase is the main strengthening phase in the as-forged alloy. The LPSO phase and refinement of grains contribute to the strength improvement of the alloy after forging process. The optimal mechanical properties of the alloy are obtained when it is aged at 200 deg. C for 60 h, which mainly owes to the precipitation of large amounts of β' and 14H-type LPSO phases on the α-Mg matrix. The growth of secondary phases, widening of soft precipitate free zones and coarsening of grains during subsequent ageing process at higher temperature lead to the decrease of mechanical properties of the alloy.

Multi-objective optimization of swash plate forging process parameters for the die wear/service life improvement

Science.gov (United States)

Hu, X. F.; Wang, L. G.; Wu, H.; Liu, S. S.

2017-12-01

For the forging process of the swash plate, the author designed a kind of multi-index orthogonal experiment. Based on the Archard wear model, the influences of billet temperature, die temperature, forming speed, top die hardness and friction coefficient on forming load and die wear were numerically simulated by DEFORM software. Through the analysis of experimental results, the best forging process parameters were optimized and determined, which could effectively reduce the die wear and prolong the die service life. It is significant to increase the practical production of enterprise, especially to reduce the production cost and to promote enterprise profit.

Forging C-C Bonds Through Decarbonylation of Aryl Ketones.

Science.gov (United States)

Somerville, Rosie J; Martin, Ruben

2017-06-06

The ability of nickel to cleave strong σ-bonds is again in the spotlight after a recent report that demonstrates the feasibility of using nickel complexes to promote decarbonylation of diaryl ketones. This transformation involves the cleavage of two strong C-C(O) bonds and avoids the use of noble metals, hence reinforcing the potential of decarbonylation as a technique for forging C-C bonds. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Round robin test programmes in the reliability of thick section ultrasonic inspections: state of the art report

International Nuclear Information System (INIS)

Watkins, B.

1987-03-01

Inspection reliability is firstly defined and it is shown how difficult it is to be assessed as the influence of such factors as human performance, equipment malfunction and intrinsic technique capability are difficult to quantify. The manufacture of round robin test specimens is then considered: types of flaw, fabrication of test samples. The results of various round robin test programmes that have been carried out to determine both the capability and reliability of NDE to detect and size flaws in steel section for thick sections directly relevant to the requirements of the nuclear industry, are then reviewed and discussed: US Pressure Vessel research committee programme, PISC I Programme, the defect detection trials, and PISC II Programme

The Influence of Temperature on the Frictional Behavior of Duplex-Coated Die Steel Rubbing Against Forging Brass

Science.gov (United States)

Ebrahimzadeh, I.; Ashrafizadeh, F.

2015-01-01

Improvement of die life under hot forging of brass alloys is considered vital from both economical and technical points of view. One of the best methods for improving die life is duplex coatings. In this research, the influence of temperature on the tribological behavior of duplex-coated die steel rubbing against forging brass was investigated. The wear tests were performed on a pin-on-disk machine from room temperature to 700 °C; the pins were made in H13 hot work tool steel treated by plasma nitriding and by PVD coatings of TiN-TiAlN-CrAlN. The disks were machined from a two-phase brass alloy too. The results revealed that the friction coefficient of this tribosystem went through a maximum at 550 °C and decreased largely at 700 °C. Furthermore, the formation of Cr2O3 caused the reduction of friction coefficient at 700 °C. PVD coatings proved their wear resistance up to 550 °C, well above the working temperature of the brass forging dies.

[Research on the temperature field detection method of hot forging based on long-wavelength infrared spectrum].

Science.gov (United States)

Zhang, Yu-Cun; Wei, Bin; Fu, Xian-Bin

2014-02-01

A temperature field detection method based on long-wavelength infrared spectrum for hot forging is proposed in the present paper. This method combines primary spectrum pyrometry and three-stage FP-cavity LCTF. By optimizing the solutions of three group nonlinear equations in the mathematical model of temperature detection, the errors are reduced, thus measuring results will be more objective and accurate. Then the system of three-stage FP-cavity LCTF was designed on the principle of crystal birefringence. The system realized rapid selection of any wavelength in a certain wavelength range. It makes the response of the temperature measuring system rapid and accurate. As a result, without the emissivity of hot forging, the method can acquire exact information of temperature field and effectively suppress the background light radiation around the hot forging and ambient light that impact the temperature detection accuracy. Finally, the results of MATLAB showed that the infrared spectroscopy through the three-stage FP-cavity LCTF could meet the requirements of design. And experiments verified the feasibility of temperature measuring method. Compared with traditional single-band thermal infrared imager, the accuracy of measuring result was improved.

Microstructures and tensile properties of Mg–Gd–Y–Zr alloy during multidirectional forging at 773 K

International Nuclear Information System (INIS)

Tang, Liechong; Liu, Chuming; Chen, Zhiyong; Ji, Dawei; Xiao, Hongchao

2013-01-01

Highlights: • Rare earth (RE) containing Mg–Gd–Y–Zr alloy was successfully multidirectional forged for 8 passes without any cracks. • Initial coarse grains was refined due to a combination of discontinuous and continuous dynamic recrystallization. • The alloy MDFed after 6 passes exhibited an excellent balance of strength and ductility at room temperature. - Abstract: A homogenized Mg–10Gd–4.8Y–0.6Zr (wt.%) alloy was subjected to multidirectional forging (MDF) at 773 K. It was shown that the average grain size decreased with increasing cumulative strain till 6 passes. Uniform fine-grained structure with an average grain size of 9.3 μm was achieved after 6 passes, i.e., cumulative strain of 1.8. Results revealed that grain refinement was induced by a complicated combination of discontinuous dynamic recrystallization at low strain regions and continuous dynamic recrystallization or rotation recrystallization at medium-to-high strain regions. The alloy multi-directionally forged (MDFed) for 6 passes exhibited an excellent balance of strength and ductility at room temperature with ultimate tensile strength (UTS) of 336 MPa and elongation to fracture of 21.0%

The analysis of forming and strain state of the hollow step forgings during the enlarging process

Directory of Open Access Journals (Sweden)

Олег Євгенійович Марков

2017-12-01

Full Text Available Improving safety, accelerating construction and extending the life of nuclear power plants is one of the main directions of the development of the energy industry. From this point of view, much attention is being paid to the production of forgings, which combine a few details today. This requires the use of new technologies with the use of non-standard tools. The purpose of the work is analyze of the shape and the deformation state of the conical stepped forging when rolling the stepped workpiece with the simultaneous deformation of the protuberance and the ledge. The simulation was performed using finite element method, which is consistent with experimental data. Experimental studies were carried out on lead models. Rolling of stepped workpiece with simultaneous deformation of the protrusion and ledge leads to the appearance of conical forging. Taper on the side of the ledge occurs at the initial stage of rolling and during the whole process increases. The emergence of a conical shape is explained by the fact that during slipping, with the same absolute deformation (stroke, the ledge gets more accumulated deformation through a more precise wall.

The Forging of a White Gay Aesthetic at the Saint, 1980–84

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Tim Lawrence

2011-06-01

Full Text Available Based on original interviews with key protagonists and documentary research, the article examines the way in which the DJs who worked at the Saint forged a white gay aesthetic across the first half of the 1980s. A private party located in the East Village, New York, the Saint attracted a privileged white male crowd, and this group's position within the emerging culture of neoliberalism, along with the deepening impact of the AIDS epidemic, encouraged its spinners to sever their ties with sounds that were associated with blackness. However, if Saint DJs rejected a high proportion of records that were being released by New York's independents, and also snubbed Chicago house when it broke in 1985, their forging of an aesthetic that emphasised seamless transitions, often between records that contained similar sonic qualities, preempted the style of mixing that would be popularised in house music culture.

Effect of the As-Forged and Heat-Treated Microstructure on the Room Temperature Anisotropic Ductile Fracture of Inconel 718

Science.gov (United States)

Teimouri, Javad; Hosseini, Seyed Rahman; Farmanesh, Khosro

2018-05-01

The purpose of the present work was to investigate the effect of primary carbides and the δ-phase on the anisotropic ductile fracture of Inconel 718 in the forging process. Inconel 718 alloys were prepared by VIM + VAR processes with various carbon contents (0.009 and 0.027 wt.%). Then, the alloys were forged and annealed at temperatures of 980 and 1030 °C. The room temperature mechanical anisotropy of the alloys was evaluated at the longitudinal direction (LD) and transverse direction (TD). Tensile and impact tests were used to characterize the mechanical properties of the specimens. The microstructural characterization and the fractography of the alloys were carried out by FE-SEM. The obtained results showed that the fracture strain and the impact energy in the TD were 30-50% lower than the LD. The fracture was accelerated by the δ-phase, leading to the reduction of impact energy in the longitudinal and the lateral directions up to 50%. The low-carbon alloy indicated similar characteristics in both the LD and the TD. Aligned carbides changed the fracture path from a zigzag path in the LD to a fibrous path in the TD, while the δ-phase created a flat fracture path. The shear lip area ratio in the tensile fracture cross section was decreased by reducing ductility.

Quality surveillance for steel forgings of SA508 Gr.3 used on the main NI equipment of AP1000 nuclear island

International Nuclear Information System (INIS)

Liu Lizhao

2011-01-01

Being a type of steel with ideal weldability, outstanding ability of anti-neutron irradiation embitterment and good property of fracture toughness and impact toughness, the steel of ASME SA508-3 was used widely for the nuclear island equipment of PWR Nuclear Power Plant. For the 3rd generation nuclear power plant AP1000, all large forgings and some critical components of the SG, RV and PRZ adopt this steel. Through analysis on the critical technical points during manufacturing of the SA508-3 forgings, this article try to identify the key points should be paid attention during the quality surveillance for this type of forgings, and to put forward the supervision method and focus during quality surveillance activities. (author)

Choroidal thickness in Malaysian eyes with full-thickness macular holes

Directory of Open Access Journals (Sweden)

Chew Y Tan

2018-02-01

Full Text Available AIM: To compare choroidal thickness at the macula in eyes with unilateral idiopathic full-thickness macular holes(FTMHwith that of unaffected fellow eyes, and eyes of normal control patients.METHODS: Cross-sectional study. Thirty patients with unilateral idiopathic FTMH and thirty age, sex, and race-matched controls were recruited. Axial lengths were measured using laser interferometry. Enhanced depth imaging optical coherence tomography images were obtained using Heidelberg spectral-domain optical coherence tomography. Choroidal thickness was measured at the fovea, and at 1 mm and 2 mm nasally, temporally, superiorly and inferiorly from the center of the fovea. Statistical analysis was performed using independent and paired t-tests, chi-square tests, and Pearson correlation tests(PRESULTS: The mean subfoveal choroidal thickness was 201.0±44.0 μm in the FTMH group, 225.3±51.4 μm in the fellow eye group and 262.3±70.3 μm in the control group. The choroid was thinner in FTMH eyes at all locations when compared to control eyes(PPP>0.05. Choroidal thickness was generally highest subfoveally and lowest nasally. Subfoveal choroidal thickness was negatively correlated with age(r=-0.278, P=0.032, and axial length(r=-0.328, P=0.011.CONCLUSION: Choroidal thickness is lower in both eyes of patients with unilateral FTMH compared to healthy control eyes.

Characterization of a Viking Blade Fabricated by Traditional Forging Techniques

Science.gov (United States)

Vo, H.; Frazer, D.; Bailey, N.; Traylor, R.; Austin, J.; Pringle, J.; Bickel, J.; Connick, R.; Connick, W.; Hosemann, P.

2016-12-01

A team of students from the University of California, Berkeley, participated in a blade-smithing competition hosted by the Minerals, Metals, and Materials Society at the TMS 2015 144th annual meeting and exhibition. Motivated by ancient forging methods, the UC Berkeley team chose to fabricate our blade from historical smithing techniques utilizing naturally-occurring deposits of iron ore. This approach resulted in receiving the "Best Example of a Traditional Blade Process/Ore Smelting Technique" award for our blade named "Berkelium." First, iron-enriched sand was collected from local beaches. Magnetite (Fe3O4) was then extracted from the sand and smelted into individual high- and low-carbon steel ingots. Layers of high- and low-carbon steels were forge-welded together, predominantly by hand, to form a composite material. Optical microscopy, energy dispersive spectroscopy, and Vickers hardness mechanical testing were conducted at different stages throughout the blade-making process to evaluate the microstructure and hardness evolution during formation. It was found that the pre-heat-treated blade microstructure was composed of ferrite and pearlite, and contained many nonmetallic inclusions. A final heat treatment was performed, which caused the average hardness of the blade edge to increase by more than a factor of two, indicating a martensitic transformation.

Diagnosis of bronchiectasis with multislice spiral CT: accuracy of 3-mm-thick structured sections

Energy Technology Data Exchange (ETDEWEB)

Remy-Jardin, Martine; Amara, Assia; Campistron, Philippe; Mastora, Ioana; Remy, Jacques [Department of Radiology, Hospital Calmette, University Center of Lille, Boulevard Jules Leclerc, 59037, Lille Cedex (France); Delannoy, Valerie; Duhamel, Alain [Department of Medical Statistics, University of Lille, Place de Verdun, 59037, Lille Cedex (France)

2003-05-01

The aim of this study was to evaluate the accuracy of 3-mm-thick reconstructed sections in the diagnosis of bronchiectasis with multislice CT (MSCT). Forty consecutive patients suspected of bronchiectasis (23 females, 17 males; mean age 51 years) underwent MSCT of the entire thorax with a 4 x 1-mm collimation (120 kV, 0.5 s/rotation, 80 mAs/slice) and a pitch of 1.75. From each data set (mean z-axis coverage: 257 mm; mean duration: 21 s), two series of images were systematically generated: 1-mm (group 1) and 3-mm (group 2)-thick reconstructed scans. Both series of images were obtained at 10-mm intervals and reconstructed with a high-spatial-frequency algorithm. Two observers independently analyzed the presence of bronchiectasis and associated abnormalities in group-1 and group-2 lung images. No significant difference between group 1 and group 2 was found in: (a) the detection of bronchiectasis, identified in 24 patients (60%) in group 1 and in 23 patients (57.5%) in group 2 (p=0.08); (b) the evaluation of the extent of bronchiectasis, identifying focal bronchiectasis in 10 patients (25%) in group 1 and 7 patients (17.5%) in group 2 (p=0.39) and multifocal bronchiectasis in 16 patients (40%) in both groups; (c) the characterisation of bronchiectasis (cylindral bronchiectasis: group 1, n=24, 60%; group 2, n=21, 53%, p=0.08); varicose bronchiectasis: group 1, n=5, 12.5%; group 2, n=6, 15%, p=0.56; and cystic bronchiectasis: group 1, n=2, 5%; group 2, n=2, 5%. Apart from the identification of abnormal bronchial wall thickening (group 2, n=35, 87.5%, vs group 1, n=31, 77.5%, p<0.05), recognition of associated bronchopulmonary anomalies did not differ between the two groups. This study demonstrates a comparable accuracy of the 3- and 1-mm-thick reconstructed scans in the detection and characterization of bronchiectasis. These results suggest the potential usefulness of 3-mm-thick scans generated from 4 x 2.5-mm acquisitions in the screening of bronchiectasis, which would

Friction welding of a nickel free high nitrogen steel: influence of forge force on microstructure, mechanical properties and pitting corrosion resistance

Directory of Open Access Journals (Sweden)

Mrityunjoy Hazra

2014-01-01

Full Text Available In the present work, nickel free high nitrogen austenitic stainless steel specimens were joined by continuous drive friction welding process by varying the amount of forge (upsetting force and keeping other friction welding parameters such as friction force, burn-off, upset time and speed of rotation as constant at appropriate levels. The joint characterization studies include microstructural examination and evaluation of mechanical (micro-hardness, impact toughness and tensile and pitting corrosion behaviour. The integrity of the joint, as determined by the optical microscopy was very high and no crack and area of incomplete bonding were observed. Welds exhibited poor Charpy impact toughness than the parent material. Toughness for friction weld specimens decreased with increase in forge force. The tensile properties of all the welds were almost the same (irrespective of the value of the applied forge force and inferior to those of the parent material. The joints failed in the weld region for all the weld specimens. Weldments exhibited lower pitting corrosion resistance than the parent material and the corrosion resistance of the weld specimens was found to decrease with increase in forge force.

FLANDES, Flange Design for He Circuits by Taylor-Forge Method

International Nuclear Information System (INIS)

Pitchford, B.E.

1977-01-01

1 - Nature of the physical problem solved: Flange design for helium circuits. 2 - Method of solution: This is a flange design programme based on the Taylor forge method with an additional calculation of flange rotation and bolt load change during the application of internal pressure. The method relates only to the integral hub type of flange, with or without a secondary O-ring seal but will deal also with the flange and cover plate case

Experience manufacturing and properties of the high-strength corrosion-resistant magnetic 03Kh12K12D2 steel

International Nuclear Information System (INIS)

Fel'dgandler, Eh.G.; Moshkevich, E.I.; Bakuma, S.F.; Bulat, S.I.; Tikhonenko, V.D.

1976-01-01

In industrial conditions, steel 03Kh12K12D2 (DI48-VD) was melted in a 7-tinduction furnace with subsequent vacuum arc remelting. Ingots of dia 500 and 630 mm were forged into slabs and forgings. The slabs were rolled into sheets, 40 mm thick, and the forgings were rolled into sectional shapes. To obtain the optimum mechanical, corrosion, and magnetic properties, the metal was annealed at 600 deg C (10 hr) and 650 deg C (5 and 10 hr). The developed melting and remelting process enabled to obtain steel meeting all the requirements as for the chemical composition, workability, and mechanical magnetic properties. On testing in water with high parameters (200 deg C, 16 kgf/cm 2 ) and in synthetic sea water (70-90 deg C) the corrosion rate did not exceed 1 μm per year

Analysis of thick brain sections by obverse-reverse computer microscopy: application of a new, high clarity Golgi-Nissl stain.

Science.gov (United States)

Glaser, E M; Van der Loos, H

1981-08-01

Exceptionally clear Golgi-Nissl sections of 300 micron thickness have been morphometrically studied by light microscopy using oil immersion objectives. The clarity results from a new variation of a staining procedure that combines Golgi and Nissl images in one section. A viewing technique has been developed that permits a histologic preparation to be examined from its obverse (or normally viewed) side and its reverse (or under) side. The technique was designed for use with a computer microscope but can be employed with any light microscope whose stage position can be measured within 100 micron. Sections thicker than 300 micron can be studied dependent on the working distance of the objective lens, provided that the clarity of the material permits it.

Three-dimensional primate molar enamel thickness.

Science.gov (United States)

Olejniczak, Anthony J; Tafforeau, Paul; Feeney, Robin N M; Martin, Lawrence B

2008-02-01

Molar enamel thickness has played an important role in the taxonomic, phylogenetic, and dietary assessments of fossil primate teeth for nearly 90 years. Despite the frequency with which enamel thickness is discussed in paleoanthropological discourse, methods used to attain information about enamel thickness are destructive and record information from only a single plane of section. Such semidestructive planar methods limit sample sizes and ignore dimensional data that may be culled from the entire length of a tooth. In light of recently developed techniques to investigate enamel thickness in 3D and the frequent use of enamel thickness in dietary and phylogenetic interpretations of living and fossil primates, the study presented here aims to produce and make available to other researchers a database of 3D enamel thickness measurements of primate molars (n=182 molars). The 3D enamel thickness measurements reported here generally agree with 2D studies. Hominoids show a broad range of relative enamel thicknesses, and cercopithecoids have relatively thicker enamel than ceboids, which in turn have relatively thicker enamel than strepsirrhine primates, on average. Past studies performed using 2D sections appear to have accurately diagnosed the 3D relative enamel thickness condition in great apes and humans: Gorilla has the relatively thinnest enamel, Pan has relatively thinner enamel than Pongo, and Homo has the relatively thickest enamel. Although the data set presented here has some taxonomic gaps, it may serve as a useful reference for researchers investigating enamel thickness in fossil taxa and studies of primate gnathic biology.

eFORGE : A Tool for Identifying Cell Type-Specific Signal in Epigenomic Data

NARCIS (Netherlands)

Breeze, Charles E.; Paul, Dirk S.; van Dongen, Jenny; Butcher, Lee M.; Ambrose, John C.; Barrett, James E.; Lowe, Robert; Rakyan, Vardhman K.; Iotchkova, Valentina; Frontini, Mattia; Downes, Kate; Ouwehand, Willem H.; Laperle, Jonathan; Jacques, Pierre-ETienne; Bourque, Guillaume; Bergmann, Anke K.; Siebert, Reiner; Vellenga, Edo; Saeed, Sadia; Matarese, Filomena; Martens, Joost H. A.; Stunnenberg, Hendrik G.; Teschendorff, Andrew E.; Herrero, Javier; Birney, Ewan; Dunham, Ian; Beck, Stephan

2016-01-01

Epigenome-wide association studies (EWAS) provide an alternative approach for studying human disease through consideration of non-genetic variants such as altered DNA methylation. To advance the complex interpretation of EWAS, we developed eFORGE (http://eforge.cs.ucl.ac.uk/), a new stand-alone and

Precipitation-hardening stainless steel bars, shapes, and forgings (ASME SA-564 with additional requirements)

International Nuclear Information System (INIS)

1975-05-01

A standard prescribing requirements for precipitation-hardening stainless steel bars, shapes, and forgings (ASME SA-564 with additional requirements) for nuclear and associated applications is presented. This standard supersedes RDT M 7-6T, dated January 1974. (U.S.)

Research on damage evolution and damage model of 316LN steel during forging

Energy Technology Data Exchange (ETDEWEB)

Duan, X.W., E-mail: dxwmike1998@sina.com; Liu, J.S.

2013-12-20

The tensile tests and unloading tensile experiments of 316LN steel were conducted. The damage evolution processes were investigated by optical microscope. The fracture was studied using a Scanning Electron Microscope (SEM) and optical microscope, of which, the chemical compositions were analyzed by Energy Dispersive Spectrometer (EDS). The results show that voids nucleate by decohesion of Al{sub 2}O{sub 3} inclusions–matrix interface and mainly along the grain boundary, especially, at triangular grain boundary junctions. The tensile processes were simulated by Deform2D under different deformation conditions. The critical damage values were obtained. The model between the critical damage value, temperature and strain rate was established by regression analysis. A combination of numerical simulation and upsetting experiments was applied for verifying the accuracy and reliability of critical damage value. These damage values can be used to predict the initiation of voids during 316LN steel hot forging. So, they have important instructional effects on designing forging technology of 316LN steel.

Selection of the optimal hard facing (HF technology of damaged forging dies based on cooling time t8/5

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D. Arsić

2016-01-01

Full Text Available In exploitation, the forging dies are exposed to heating up to very high temperatures, variable loads: compressive, impact and shear. In this paper, the reparatory hard facing of the damaged forging dies is considered. The objective was to establish the optimal reparatory technology based on cooling time t8/5 . The verification of the adopted technology was done by investigation of the hard faced layers microstructure and measurements of hardness within the welded layers’ characteristic zones. Cooling time was determined theoretically, numerically and experimentally.

Increasing of the lifetime of large forging dies by repairwelding

Science.gov (United States)

Duchek, M.; Koukolikova, M.; Kotous, J.; Majer, M.

2018-02-01

Repair welding is often used for rebuilding discarded or failed forging dies. It saves the cost of new tools. Increased useful life of repaired dies is another motivation for repair welding. This article focuses on the development of new filler materials for this purpose. The main goal was to prolong the life of tools of DIN 1.2714 material. Filler wires of two chemistries were made and several samples were experimentally welded. Metallographic and tribological analyses were carried out.

Use of Gleeble MAXStrain unit for study of damage development in hot forging

NARCIS (Netherlands)

Geijselaers, Hubertus J.M.; Wang, Chao; Miroux, A.; Recina, V.; van den Boogaard, Antonius H.; Saanouni, K.

2016-01-01

The standard Gleeble MAXStrain unit has been modified to allow axial elongation. Analyses indicate that in this way both positive and negative hydrostatic stresses can be achieved during forging simulations, depending on the amount of strain per hit. This opens the way to the study of the effect of

Stress corrosion of low alloy steel forgings

International Nuclear Information System (INIS)

Thornton, D.V.; Mould, P.B.; Patrick, E.C.

1976-01-01

The catastrophic failure of a steam turbine rotor disc at Hinkley Point 'A' Power station was shown to have been caused by the growth of a stress corrosion crack to critical dimensions. This failure has promoted great interest in the stress corrosion susceptibility of medium strength low alloy steel forgings in steam environments. Consequently, initiation and growth of stress corrosion cracks of typical disc steels have been investigated in steam and also in water at 95 0 C. Cracking has been shown to occur, predominantly in an intergranular manner, with growth rates of between 10 -9 and 10 -7 mm sec. -1 . It is observed that corrosion pitting and oxide penetration prior to the establishment of a stress corrosion crack in the plain samples. (author)

Experimental and numerical research on forging with torsion

Science.gov (United States)

Petrov, Mikhail A.; Subich, Vadim N.; Petrov, Pavel A.

2017-10-01

Increasing the efficiency of the technological operations of blank production is closely related to the computer-aided technologies (CAx). On the one hand, the practical result represents reality exactly. On the other hand, the development procedure of new process development demands unrestricted resources, which are limited on the SMEs. The tools of CAx were successfully applied for development of new process of forging with torsion and result analysis as well. It was shown, that the theoretical calculations find the confirmation both in praxis and during numerical simulation. The mostly used constructional materials were under study. The torque angles were stated. The simulated results were evaluated by experimental procedure.

Uncertainties in thick-target PIXE analysis

International Nuclear Information System (INIS)

Campbell, J.L.; Cookson, J.A.; Paul, H.

1983-01-01

Thick-target PIXE analysis insolves uncertainties arising from the calculation of thick-target X-ray production in addition to the usual PIXE uncertainties. The calculation demands knowledge of ionization cross-sections, stopping powers and photon attenuation coefficients. Information on these is reviewed critically and a computational method is used to estimate the uncertainties transmitted from this data base into results of thick-target PIXE analyses with reference to particular specimen types using beams of 2-3 MeV protons. A detailed assessment of the accuracy of thick-target PIXE is presented. (orig.)

Magnetostriction of heavily deformed Fe–Co binary alloys prepared by forging and cold rolling

International Nuclear Information System (INIS)

Yamaura, Shin-ichi; Nakajima, Takashi; Satoh, Takenobu; Ebata, Takashi; Furuya, Yasubumi

2015-01-01

Highlights: • The as-forged Fe 25 Co 75 alloy shows the magnetostriction of 108 ppm. • The as-cold rolled Fe 25 Co 75 alloy shows the magnetostriction of 140 ppm. • Magnetostriction of Fe–Co alloy reached the maximum in a single bcc state. • Fcc phase is harmful to the increase in magnetostriction of Fe–Co alloy. • Fcc phase precipitation in Fe–Co alloy can be suppressed by cold rolling. - Abstract: Magnetostriction of Fe 1−x Co x (x = 50–90 at%) alloys prepared by forging and subsequent cold-rolling was studied as functions of alloy compositions and thermomechanical treatments. Magnetostriction of the as-forged Fe 25 Co 75 alloy was 108 ppm and that of the as-cold rolled Fe 25 Co 75 alloy measured parallel to the rolling direction (RD) was 128 ppm. The cold-rolled Fe 25 Co 75 alloy possessed a nearly {1 0 0}<0 1 1> texture, leading to the maximum magnetostriction of 140 ppm when measured at an angle of 45° to RD. Moreover, the fully annealed Fe 25 Co 75 and Fe 20 Co 80 alloys were gradually cold rolled and magnetostriction were measured. Results showed that the magnetostriction of those cold-rolled alloys drastically increased with increasing reduction rate. According to the XRD and TEM observations, intensity of the fcc peak gradually decreased with increasing reduction rate and that the alloys became to be in a bcc single state at a reduction rate higher than 90%, leading to a drastic increase in magnetostriction

Design of the Driving and Clamp Rotation Hydraulic Control System for the Heavy Load Forging Manipulator

Directory of Open Access Journals (Sweden)

Li Geqiang

2015-01-01

Full Text Available The manipulator was equipped with full hydraulic drive. We designed the hydraulic systems for the driving and clamping rotation. We used a fuzzy PID control strategy to design the electro-hydraulic proportional control system. We built a united simulation model based on the co-simulation of MATLAB/Simulink and AMEsim. A mathematical model of the system was also established. We did separate simulations of the system’s dynamic characteristics for fast forging and normal forging working conditions. The parameters were optimized. The field test shows that the steady-state error of the hydraulic system is small and the system response is fast. The system’s rapid response speed, high precision, and stability under heavy load were realized.

Forging Alliances in Interdisciplinary Rehabilitation Research (FAIRR): A Logic Model.

Science.gov (United States)

Gill, Simone V; Khetani, Mary A; Yinusa-Nyahkoon, Leanne; McManus, Beth; Gardiner, Paula M; Tickle-Degnen, Linda

2017-07-01

In a patient-centered care era, rehabilitation can benefit from researcher-clinician collaboration to effectively and efficiently produce the interdisciplinary science that is needed to improve patient-centered outcomes. The authors propose the use of the Forging Alliances in Interdisciplinary Rehabilitation Research (FAIRR) logic model to provide guidance to rehabilitation scientists and clinicians who are committed to growing their involvement in interdisciplinary rehabilitation research. We describe the importance and key characteristics of the FAIRR model for conducting interdisciplinary rehabilitation research.

Electro sinter forging of titanium disks

DEFF Research Database (Denmark)

Cannella, Emanuele; Nielsen, Chris Valentin; Bay, Niels Oluf

by measuring the electrical resistance during the sintering process [5], since low electrical resistance corresponds to high density. It is, however, necessary to be aware that increased temperature, on the other hand, increases the resistance. SEM micrographs and Computed Tomography (CT) are carried out......Electro sinter forging (ESF) is a new sintering process based on the principle of electrical Joule heating. In the present work, middle frequency direct current (MFDC) was flowing through the powder compact, which was under mechanical pressure. The main parameters are the high electrical current......, up to 10 kA, and the low voltage, 1-2 V, resulting in heat generation in the powder. Figure 1 shows the experimental setup. The punches were made of a conductive material; namely a copper alloy. The die, which has to be electrically insulating, was made of alumina. The ESF process takes 3-4s...

Joining thick section aluminum to steel with suppressed FeAl intermetallic formation via friction stir dovetailing

Energy Technology Data Exchange (ETDEWEB)

Reza-E-Rabby, Md.; Ross, Kenneth; Overman, Nicole R.; Olszta, Matthew J.; McDonnell, Martin; Whalen, Scott A.

2018-04-01

A new solid-phase technique called friction stir dovetailing (FSD) has been developed for joining thick section aluminum to steel. In FSD, mechanical interlocks are formed at the aluminum-steel interface and are reinforced by metallurgical bonds where intermetallic growth has been uniquely suppressed. Lap shear testing shows superior strength and extension at failure compared to popular friction stir approaches where metallurgical bonding is the only joining mechanism. High resolution microscopy revealed the presence of a 40-70 nm interlayer having a composition of 76.4 at% Al, 18.4 at% Fe, and 5.2 at% Si, suggestive of limited FeAl3 intermetallic formation.

Nearshore sediment thickness, Fire Island, New York

Science.gov (United States)

Locker, Stanley D.; Miselis, Jennifer L.; Buster, Noreen A.; Hapke, Cheryl J.; Wadman, Heidi M.; McNinch, Jesse E.; Forde, Arnell S.; Stalk, Chelsea A.

2017-04-03

Investigations of coastal change at Fire Island, New York (N.Y.), sought to characterize sediment budgets and determine geologic framework controls on coastal processes. Nearshore sediment thickness is critical for assessing coastal system sediment availability, but it is largely unquantified due to the difficulty of conducting geological or geophysical surveys across the nearshore. This study used an amphibious vessel to acquire chirp subbottom profiles. These profiles were used to characterize nearshore geology and provide an assessment of nearshore sediment volume. Two resulting sediment-thickness maps are provided: total Holocene sediment thickness and the thickness of the active shoreface. The Holocene sediment section represents deposition above the maximum flooding surface that is related to the most recent marine transgression. The active shoreface section is the uppermost Holocene sediment, which is interpreted to represent the portion of the shoreface thought to contribute to present and future coastal behavior. The sediment distribution patterns correspond to previously defined zones of erosion, accretion, and stability along the island, demonstrating the importance of sediment availability in the coastal response to storms and seasonal variability. The eastern zone has a thin nearshore sediment thickness, except for an ebb-tidal deposit at the wilderness breach caused by Hurricane Sandy. Thicker sediment is found along a central zone that includes shoreface-attached sand ridges, which is consistent with a stable or accretional coastline in this area. The thickest overall Holocene section is found in the western zone of the study, where a thicker lower section of Holocene sediment appears related to the westward migration of Fire Island Inlet over several hundred years.

The Ties That Bind: How Social Capital Is Forged and Forfeited in Teacher Communities

Science.gov (United States)

Bridwell-Mitchell, E. N.; Cooc, North

2016-01-01

The effects of social capital on school improvement make it important to understand how teachers forge, maintain, or forfeit collegial relationships. Two common explanations focused on formal organizational features and individual characteristics do not address how social capital accrues from informal dynamics of teachers' interactions in…

Synthetic aperture focusing technique in real-time and tandem operation for thick section steels

International Nuclear Information System (INIS)

Doctor, S.R.; Hall, T.E.; Reid, L.D.; Mart, G.A.

1988-01-01

The authors report on a program underway at Pacific Northwest Laboratory (PNL) to move the synthetic aperture focusing technique (SAFT) from the laboratory into the field for the purpose of inspecting light-water reactor (LWR) components. The SAFT technology was developed to produce high-resolution and high signal-to-noise ratio images of ultrasonic anomalies in materials. Other researchers have been involved in developing the 2-D or line SAFT technology, but the one thing that has limited the acceptance of 38-D SAFT is the slow processing rates. This paper describes how a special purpose processor can be used to achieve processing rates of 10 A-scans/second or larger. The tandem mode has been successfully used with SAFT but only on this materials. This paper also describes how to effectively implement the tandem mode for thick section materials

Brittle Fracture Behaviors of Large Die Holders Used in Hot Die Forging

Directory of Open Access Journals (Sweden)

Weifang Zhang

2017-05-01

Full Text Available Brittle fracture of large forging equipment usually leads to catastrophic consequences. To avoid this kind of accident, the brittle fracture behaviors of a large die holder were studied by simulating the practical application. The die holder is used on the large die forging press, and it is made of 55NiCrMoV7 hot-work tool steel. Detailed investigations including mechanical properties analysis, metallographic observation, fractography, transmission electron microscope (TEM analysis and selected area electron diffraction (SAED were conducted. The results reveal that the material generated a large quantity of large size polyhedral M23C6 (M: Fe and Cr mainly and elongated M3C (M: Fe mainly carbides along the martensitic lath boundaries when the die holder was recurrently tempered and water-cooled at 250 °C during the service. The large size carbides lead to the material embrittlement and impact toughness degradation, and further resulted in the brittle fracture of the die holder. Therefore, the operation specification must be emphasized to avoid the die holder being cooled by using water, which is aimed at accelerating the cooling.

THE LEGAL PROTECTION FOR REAL LAND RIGHT HOLDER IN CASE OF FORGED RINCIK

Directory of Open Access Journals (Sweden)

Nirwana Nirwana

2017-12-01

Full Text Available The legal Protection For Real Land Right Holder in Case of Forged Rincik. The research aimed to investigate (1 the legal protection for the land owner whose possession was based on rincik evidence, and (2 the legal protection on the good-will buyer based on the forged rincik document used in the land sale transaction. This was the normative legal research, also called the library research or documentary study because the research was only conducted on the written regulations or other legal materials or secondary data consisting of the primary and secondary legal materials. The interview was performed to strengthen the theories and opinions in the research. The research also used the Secondary data. the data were analysed and presented using the qualitative descriptive method. The research result indicate that: (1 the real land owner with rincik possession issued after the year 1960 based on the decision of Indonesian Supreme Court No. 560K / PID / 2008 has not been fully protected due to the fact that the seller is funished for forging the rincik., returning the right to the land owner can not be carried out due to the decision of Indonesian Supreme Court Number. 482 / PK / Pdt / 2014 which make the buyer win, while the real land owner is the directed to sue the land seller to give the compensation: and (2 the legal protection on the good faith buyer based on forget rincik in the land sale transaction has been fully protected and has the ringt to possess the land based on the decision of Indonesian Supreme Court Number. 482/PK/Pdt/2014 because the buyer has bought the land in the presence of Temporary Land Title Registar.

An Assessment of the Ductile Fracture Behavior of Hot Isostatically Pressed and Forged 304L Stainless Steel

Science.gov (United States)

Cooper, A. J.; Smith, R. J.; Sherry, A. H.

2017-05-01

Type 300 austenitic stainless steel manufactured by hot isostatic pressing (HIP) has recently been shown to exhibit subtly different fracture behavior from that of equivalent graded forged steel, whereby the oxygen remaining in the component after HIP manifests itself in the austenite matrix as nonmetallic oxide inclusions. These inclusions facilitate fracture by acting as nucleation sites for the initiation, growth, and coalescence of microvoids in the plastically deforming austenite matrix. Here, we perform analyses based on the Rice-Tracey (RT) void growth model, supported by instrumented Charpy and J-integral fracture toughness testing at ambient temperature, to characterize the degree of void growth ahead of both a V-notch and crack in 304L stainless steel. We show that the hot isostatically pressed (HIP'd) 304L steel exhibits a lower critical void growth at the onset of fracture than that observed in forged 304L steel, which ultimately results in HIP'd steel exhibiting lower fracture toughness at initiation and impact toughness. Although the reduction in toughness of HIP'd steel is not detrimental to its use, due to the steel's sufficiently high toughness, the study does indicate that HIP'd and forged 304L steel behave as subtly different materials at a microstructural level with respect to their fracture behavior.

Tool design and materials for electro sinter forging (ESF)

DEFF Research Database (Denmark)

Cannella, Emanuele; Nielsen, Chris Valentin

) process, the main requirement is the electrical current passing through the electrical conducting powder. To obtain this, a closed-die setup with electrical insulating properties was used. Furthermore, the alignment between the compacting punch and die needed to be ensured by pre-aligning or alternatively...... by using an alignment system. The present work is focused on the designing phase of a tool for the electro sinter forging of a disc, made from titanium powder. By applying a pre-alignment system, the setup resulted suitable for this application. A tool design for sintering rings is also showed....

Modeling Cavitation in ICE Pistons Made with Isothermal Forging

Directory of Open Access Journals (Sweden)

V.V. Astanin

2014-07-01

Full Text Available Possible causes for cavitations in parts made with an Al-Si eutectic alloy AK12D (AlSi12 were explored with mathematical and physical modeling with involved acoustic emission. Pores were formed from micro-cracks, which appear during the early stages of a deformation process, with the help of micro-stresses appearing at phase boundaries (Al/Si interface due to thermal expansion. At the design stage of isothermal forgings of such products it is recommended to provide a scheme of the deformed shape, which is under uniform compression, to compensate for the inter-phase stresses.

Deducing material quality in cast and hot-forged steels by new bending test

Science.gov (United States)

Valberg, Henry; Langøy, Morten; Nedreberg, Mette; Helvig, Torgeir

2017-10-01

A special bend test has been developed and applied for the purpose of characterization and comparison of the material ductility in crankpin steel discs manufactured by casting, or casting subsequently followed by hot open-die forging (ODF) or closed-die forging (CDF). The bending test specimen consists of a small rectangular plate of material with a round hole cut out in the middle. The "eye-shape" specimens were cut out from various positions either near to the surface of, or from the interior of the discs. The test method revealed differences in ductility for the investigated materials, and for different depth positions inside the discs. The roughening of the specimen surface on the top-side of the specimen bend also varied dependent on the processing method for the material. Current results show that this test method is useful for evaluation of material quality in differently processed material. Experimental bend test results are presented for differently processed variants of the same material, i.e., crankpin discs either made by solely casting or casting subsequently followed by hot working either by ODF or CDF.

Influence of the hydrostatic stress component on critical surface expansion in forging compound products

DEFF Research Database (Denmark)

Vorm, T; Bay, Niels; Wanheim, Tarras

1974-01-01

of a superimposed hydrostatic pressure on the critical surface expansion during a forging process. The critical surface expansion appears to decrease with increasing hydrostatic pressure. This may be due to the fact that the close contact between the materials necessary to obtain bonding is created by a micro...

Magnetostriction of heavily deformed Fe–Co binary alloys prepared by forging and cold rolling

Energy Technology Data Exchange (ETDEWEB)

Yamaura, Shin-ichi, E-mail: yamaura@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba, Sendai 980-8577 (Japan); Nakajima, Takashi [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba, Sendai 980-8577 (Japan); Satoh, Takenobu; Ebata, Takashi [Tohoku Steel, Co., Ltd., 23 Nishigaoka, Murata, Murata-machi, Shibata 989-1393 (Japan); Furuya, Yasubumi [North Japan Research Institute for Sustainable Energy, Hirosaki University, 2-1-3 Matsubara, Aomori 030-0813 (Japan)

2015-03-15

Highlights: • The as-forged Fe{sub 25}Co{sub 75} alloy shows the magnetostriction of 108 ppm. • The as-cold rolled Fe{sub 25}Co{sub 75} alloy shows the magnetostriction of 140 ppm. • Magnetostriction of Fe–Co alloy reached the maximum in a single bcc state. • Fcc phase is harmful to the increase in magnetostriction of Fe–Co alloy. • Fcc phase precipitation in Fe–Co alloy can be suppressed by cold rolling. - Abstract: Magnetostriction of Fe{sub 1−x}Co{sub x} (x = 50–90 at%) alloys prepared by forging and subsequent cold-rolling was studied as functions of alloy compositions and thermomechanical treatments. Magnetostriction of the as-forged Fe{sub 25}Co{sub 75} alloy was 108 ppm and that of the as-cold rolled Fe{sub 25}Co{sub 75} alloy measured parallel to the rolling direction (RD) was 128 ppm. The cold-rolled Fe{sub 25}Co{sub 75} alloy possessed a nearly {1 0 0}<0 1 1> texture, leading to the maximum magnetostriction of 140 ppm when measured at an angle of 45° to RD. Moreover, the fully annealed Fe{sub 25}Co{sub 75} and Fe{sub 20}Co{sub 80} alloys were gradually cold rolled and magnetostriction were measured. Results showed that the magnetostriction of those cold-rolled alloys drastically increased with increasing reduction rate. According to the XRD and TEM observations, intensity of the fcc peak gradually decreased with increasing reduction rate and that the alloys became to be in a bcc single state at a reduction rate higher than 90%, leading to a drastic increase in magnetostriction.

Greater Cortical Thickness in Elderly Female Yoga Practitioners—A Cross-Sectional Study

Directory of Open Access Journals (Sweden)

Rui F. Afonso

2017-06-01

Full Text Available Yoga, a mind-body activity that requires attentional engagement, has been associated with positive changes in brain structure and function, especially in areas related to awareness, attention, executive functions and memory. Normal aging, on the other hand, has also been associated with structural and functional brain changes, but these generally involve decreased cognitive functions. The aim of this cross-sectional study was to compare brain cortical thickness (CT in elderly yoga practitioners and a group of age-matched healthy non-practitioners. We tested 21 older women who had practiced hatha yoga for at least 8 years and 21 women naive to yoga, meditation or any mind-body interventions who were matched to the first group in age, years of formal education and physical activity level. A T1-weighted MPRAGE sequence was acquired for each participant. Yoga practitioners showed significantly greater CT in a left prefrontal lobe cluster, which included portions of the lateral middle frontal gyrus, anterior superior frontal gyrus and dorsal superior frontal gyrus. We found greater CT in the left prefrontal cortex of healthy elderly women who trained yoga for a minimum of 8 years compared with women in the control group.

The Use of 3D Scanning Methods to Evaluate the Hybrid Layer Used in Forging Tools in Order to Improve their Durability

Directory of Open Access Journals (Sweden)

Gronostajski Z.

2017-09-01

Full Text Available This study is focused on tools used in the industrial process of hot forging of a front wheel forging (gear wheel manufactured for the automotive industry. Five different variants were applied for the tools: 3 die inserts were coated with three different hybrid layers (PN + PVD type, i.e. AlCrTiN, AlCrTiSiN and CrN, one insert was only nitrided, and one was pad welded, to improve tool durability. The tool wear was analysed and represented by the material degradation on the working surface, based on the 3D scanning and the material growth of the periodically collected forgings. Additionally, the scanned tools were divided into two areas, in which it was found, based on the analysis, that various degradation mechanisms are predominant. Microstructural tests and hardness measurements of the analyzed tools were also performed. Based on the results, it was found that, in the central part of the die insert, thermo-mechanical fatigue, abrasive wear and plastic deformation occurred, while in the area of the bridge insert, only abrasive wear could be observed. For these areas, the loss of material was determined separately. It was established that the use of the GN+CrN and GN+AlCrTiN hybrid layers on forging tools improves their durability, while the best results in the central area were observed on the tool with the GN+CrN layer, which is the most resistant to thermo-mechanical fatigue. In the second analyzed area, good wear resistance occurred on GN+CrN, GN+AlCrTiN and pad welded inserts, for which, together with the increase of the forging number, a proportional, slight growth of the loss of material occurred.

Press forging of single crystal calcium fluoride

International Nuclear Information System (INIS)

Turk, R.R.

1975-01-01

Single crystals of high-purity calcium fluoride have been deformed uniaxially in an attempt to improve strength and resistance to cleavage, without impairing infrared transmission. Order of magnitude increases in strength, such as those found in forged KCl, have not been attained, but fine-grained polycrystalling material has been produced which is resistant to crystalline cleavage. Deformation rates of 10 -2 min -1 , reductions of 10 to 73 percent in height, and deformation temperatures of 550 to 1000 0 C have been used. Flexural strengths over 13,000 psi and grain sizes down to 5 μm have been obtained. Reduction of residual stress through heat treatment has been studied, and resultant techniques applied before, during, and after deformation. No increase in infrared absorption has been noted at the CO laser wavelength of 5.3 μm

Self-adaptive multimethod optimization applied to a tailored heating forging process

Science.gov (United States)

Baldan, M.; Steinberg, T.; Baake, E.

2018-05-01

The presented paper describes an innovative self-adaptive multi-objective optimization code. Investigation goals concern proving the superiority of this code compared to NGSA-II and applying it to an inductor’s design case study addressed to a “tailored” heating forging application. The choice of the frequency and the heating time are followed by the determination of the turns number and their positions. Finally, a straightforward optimization is performed in order to minimize energy consumption using “optimal control”.

Forging of eccentric co-extruded Al-Mg compounds and analysis of the interface strength

International Nuclear Information System (INIS)

Förster, W; Binotsch, C; Awiszus, B; Lehmann, T; Müller, J; Kirbach, C; Stockmann, M; Ihlemann, J

2016-01-01

Within the subproject B3 of the Collaborative Research Center 692 it has been shown that Al-Mg compounds with a good bonding quality can be produced by hydrostatic coextrusion. During processing by forging, the aluminum sleeve is thinned in areas of high strains depending on the component geometry. To solve this problem an eccentric core arrangement during co-extrusion was investigated. Based on the results of FE-simulations, the experimental validation is presented in this work. Rods with an offset of 0.25, 0.5 and 0.75 mm were produced by eccentric hydrostatic co-extrusion. Ultrasonic testing was used to evaluate the bonding quality across the entire rods. For the forging investigations the basic process Rising was chosen. The still good bonding quality after forging was examined by dye penetrant testing and optical microscopy. For an optimal stress transfer between the materials across the entire component, a sufficient bonding between the materials is essential. To evaluate the interface strength, a special bending test was developed. For the conception of the bending specimens it was required to analyze the Rising specimens geometry. These analyses were performed using a reconstruction of the geometrical data based on computer tomography (CT) investigations. The comparison with the numerically deter-mined Rising specimen geometry shows good correlation. Parametric Finite Element Analyses of the bending test were used to develop the load case and the specimen geometry. By means of iterative adaption of load application, bearing and specimen geometry parameters, an advantageous stress state and experimentally applicable configuration were found. Based on this conception, the experimental setup was configured and bending tests were performed. The interface strength was deter-mined by the calculation of the maximum interlaminar interfacial tension stress using the experimental interface failure force and the bending FE model. (paper)

Forging And Milling Contribution On Residual Stresses For A Textured Biphasic Titanium Alloy

International Nuclear Information System (INIS)

Deleuze, C.; Fabre, A.; Barrallier, L.; Molinas, O.

2011-01-01

Ti-10V-2Fe-3Al is a biphasic titanium alloy (α+β) used in aeronautical applications for its mechanical properties, such as its yield strength of 1200 MPa and it weighs 40% less than steel. This alloy is particularly useful for vital parts with complex geometry, because of its high forging capability. In order to predict the capability for fatigue lifetime, the designers need to know the residual stresses. X-Ray diffraction is the main experimental technique used to determine residual stresses on the surface. In this case, stress levels are primarily influenced by the complex forging and milling process. On this alloy in particular, it may be difficult to characterize stress due to modification of the microstructure close to the surface. Results obtained by x-ray analysis depend on the correct definition of the shape of the diffraction peaks. The more precisely defined the position of the peak, the more accurately the stresses are evaluated. This paper presents a method to detect if residual stresses can be characterized by x-ray diffraction. The characterization of hardness seems to be a relevant technique to quickly analyze the capability of x-ray diffraction to determine residual stresses.

Geologic thickness data: Candidate repository horizons

International Nuclear Information System (INIS)

Cross, R.W.; Fairchild, K.R.

1985-01-01

This data package contains information on the thickness of the Umtanum, McCoy Canyon, Cohassett, and Rocky Coulee flows and their intraflow structures in 20 boreholes and 2 surface sections in the Pasco Basin. Thickness data are for total flow, flow top, entablature, and colonnade (or just flow top and dense interior in some cases). Summary figures which contain descriptions and footages are included

Study of the structural and mechanical properties of the alloy U-0.2V (weight percent) forged in the α phase

International Nuclear Information System (INIS)

Couterne, A.; Guillaume, C.

1980-01-01

The effects of forging carried out in the 2 phase on the structural properties of the alloy U-0.2V (evtl.%) carburized or not have been studied. A carbon content of the order of 300 x 10 6 , contrary to the one used for the cast alloy, is neither detrimental to the micrographic structure nor to the mechanical properties of the alloy. The forged plates have a semicrystalline structure with alternative, formed bands, on the one hand by small recrystallization grains, on the other by quite deformed coarse grains. The preferential orientations developed resume to a fibrous structure. The fiber axis, practically the [002] axis, is parallell to the normal to the surface of the forged disc. This result implies a good isotropy of the dilatometric and mechanical properities in the whole plane parallel to the disc faces. A correlation has been made between the found structure and the thermal expansion of the material. Furthermore, the mechanical characteristics reach an excellent level (Rsup(M) approx. 900 MPa, A approx. 38%). (orig.)

Follow-up of hearing thresholds among forge hammering workers

Energy Technology Data Exchange (ETDEWEB)

Kamal, A.A.; Mikael, R.A.; Faris, R. (Ain Shams Univ., Abbasia, Cairo (Egypt))

1989-01-01

Hearing threshold was reexamined in a group of forge hammering workers investigated 8 years ago with consideration of the age effect and of auditory symptoms. Workers were exposed to impact noise that ranged from 112 to 139 dB(A)--at an irregular rate of 20 to 50 drop/minute--and a continuous background noise that ranged from 90 to 94 dB(A). Similar to what was observed 8 years ago, the present permanent threshold shift (PTS) showed a maximum notch at the frequency of 6 kHz and considerable elevations at the frequencies of 0.25-1 kHz. The age-corrected PTS and the postexposure hearing threshold were significantly higher than the corresponding previous values at the frequencies 0.25, 0.5, 1, and 8 kHz only. The rise was more evident at the low than at the high frequencies. Temporary threshold shift (TTS) values were significantly less than those 8 years ago. Contrary to the previous TTS, the present TTS were higher at low than at high frequencies. Although progression of PTS at the frequencies 0.25 and 0.5 kHz was continuous throughout the observed durations of exposure, progression at higher frequencies occurred essentially in the first 10 to 15 years of exposure. Thereafter, it followed a much slower rate. Tinnitus was significantly associated with difficulty in hearing the human voice and with elevation of PTS at all the tested frequencies, while acoustic after-image was significantly associated with increment of PTS at the frequencies 0.25-2 kHz. No relation between PTS and smoking was found. PTS at low frequencies may provide an indication of progression of hearing damage when the sensitivity at 6 and 4 kHz diminishes after prolonged years of exposure. Tinnitus and acoustic after-image are related to the auditory effect of forge hammering noise.

Automated estimation of choroidal thickness distribution and volume based on OCT images of posterior visual section.

Science.gov (United States)

Vupparaboina, Kiran Kumar; Nizampatnam, Srinath; Chhablani, Jay; Richhariya, Ashutosh; Jana, Soumya

2015-12-01

A variety of vision ailments are indicated by anomalies in the choroid layer of the posterior visual section. Consequently, choroidal thickness and volume measurements, usually performed by experts based on optical coherence tomography (OCT) images, have assumed diagnostic significance. Now, to save precious expert time, it has become imperative to develop automated methods. To this end, one requires choroid outer boundary (COB) detection as a crucial step, where difficulty arises as the COB divides the choroidal granularity and the scleral uniformity only notionally, without marked brightness variation. In this backdrop, we measure the structural dissimilarity between choroid and sclera by structural similarity (SSIM) index, and hence estimate the COB by thresholding. Subsequently, smooth COB estimates, mimicking manual delineation, are obtained using tensor voting. On five datasets, each consisting of 97 adult OCT B-scans, automated and manual segmentation results agree visually. We also demonstrate close statistical match (greater than 99.6% correlation) between choroidal thickness distributions obtained algorithmically and manually. Further, quantitative superiority of our method is established over existing results by respective factors of 27.67% and 76.04% in two quotient measures defined relative to observer repeatability. Finally, automated choroidal volume estimation, being attempted for the first time, also yields results in close agreement with that of manual methods. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mechanical properties of ASTM A508 Class 4 steel used in the LWBR closure head and support flange (LWBR Development Program)

International Nuclear Information System (INIS)

Allen, R.M.; Hall, J.F.

1978-07-01

The LWBR closure head and support flange are manufactured from forgings of ASTM A508 Class 4 steel rather than the ASTM A508 Class 2 forging material more commonly used in reactor vessels and closure heads. Forgings involved were approximately 300,000 pounds and 46,000 pounds. The extensive material test program conducted on ASTM A508 Class 4 LWBR forgings is described. The results of the tests confirm that the A508 Class 4 material used for the LWBR forgings has been quite good through thickness, fracture toughness, and strength properties and fully meet all specified requirements

Process parameter influence on Electro-sinter-forging (ESF) of titanium discs

DEFF Research Database (Denmark)

Cannella, Emanuele; Nielsen, Chris Valentin; Bay, Niels

Electro-sinter-forging (ESF) is a sintering process based on the resistance heating principle, which makes it faster than conventional sintering. The process is investigated as a function of the main process parameters, namely compacting pressure, electrical current density and sintering time....... The present work is focused on analysing the influence of these process parameters on the final density of a disc sample made from commercially pure titanium powder. Applying the design of experiments (DoE) approach, the electrical current was seen to be of largest influence. The maximum obtained density...

Slip-line field analysis of metal flow during two dimensional forging

International Nuclear Information System (INIS)

Fenton, R.G.; Khataan, H.A.

1981-01-01

A method of computation and a computer software package were developed for solving problems of two dimensional plastic flow between symmetrical dies of any specified shape. The load required to initiate plastic flow, the stress and velocity distributions in the plastic region of the metal, and the pressure distribution acting on the die are determined. The method can be used to solve any symmetrical plane strain flow problem regardless of the complexity of the die. The accurate solution obtained by this efficient method can provide valuable help to forging die designers. (Author) [pt

Transmission electron microscopy of Ti-12Mo-13Nb Alloy aged after heat forging; Microscopia eletronica de transmissao da liga Ti-12Mo-13Nb envelhecida apos forjamento a quente

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Nathalia Rodrigues [Centro Universitario de Volta Redonda (UNIFOA), Volta Redonda, RJ (Brazil); Baldan, Renato [Universidade de Sao Paulo (USP), Lorena, SP (Brazil). Escola de Engenharia; Nunes, Carlos Angelo; Mei, Paulo Roberto [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil); Gabriel, Sinara Borborema [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

2014-06-15

Metastable β-Ti alloys possess mechanical properties, in particular a elastic modulus that depends not only on its composition but also the applied thermomechanical treatments. These alloys require high mechanical strength and a low Young’s modulus to avoid stress shielding. Preliminary studies on the development of Ti- 13Nb-12Mo alloy showed than the better properties were obtained at aged at 500 ° C / 24 h after cold forging , whose microstructure consisted of bimodal α phase in the β matrix. In this work, Ti-12Mo-13Nb alloy was heat forged and aged at 500 deg C for 24h and the microstructure was analyzed by employing X-ray diffraction and transmission electron microscopy. According to the results, while the cold forging resulted in bimodal α phase in the β matrix, hot forging resulted in a fine and homogeneous α phase in the β matrix. (author)

Weld-forged rotors of the turbines for nuclear and thermal power plants

International Nuclear Information System (INIS)

Rudkovskij, A.F.; German, S.I.

1979-01-01

Considered is a principally new technology and equipment for assembling and welding superheavy rotors with mass up to 200 tons. Construction peculiarities and advantages of the application of weld-forged rotors are noted. The technology proposed permits to provide for a horizontal assembling, subsequent welding and quality control of rotors, one bench being used instead of three ones. The application of horizontal assembling and complex welding of rotors in one position permits not only to shorten the cycle of assembling and welding, too decrease the equipment costs and release production capacities, but also to improve substantially the quality of welds and especially the accuracy of rotor production. The equipment allows one to assemble and weld rotors with the mass up to 250 tons at maximum rotor diameter up to 2500 mm and length up to 13000 mm. Presented are data characterizing chemical composition and mechanical properties of steels used for forging of welded rotors. Also given are the results of studying mechanical properties of welded joints, welding and thermal treatment of which were made in accordance with the technology proposed. Serial production of rotors for turbines with the power of 500, 1000 and 1200 Mw is shown to be mastered along with the manufacture of welded rotors for cylinders of low, medium and high pressure turbines

Taking the Lead in Science Education: Forging Next-Generation Science Standards. International Science Benchmarking Report. Appendix

Science.gov (United States)

Achieve, Inc., 2010

2010-01-01

This appendix accompanies the report "Taking the Lead in Science Education: Forging Next-Generation Science Standards. International Science Benchmarking Report," a study conducted by Achieve to compare the science standards of 10 countries. This appendix includes the following: (1) PISA and TIMSS Assessment Rankings; (2) Courses and…

Variation in thickness of the large cryosections cut for whole-body autoradiography

International Nuclear Information System (INIS)

Ito, Tsunao; Brill, A.B.

1991-01-01

A method to assess variation in thickness of the large cryosections for whole-body autoradiography (WBARG) was described, and the degree of intraslice and interslice variations were determined for our cryomicrotome system (LKB PMV-2250). Intraslice variation in thickness of the 180 x 80 mm cryosection was 0.72-0.92 μm within the range of section thickness for WBARG (15-50 μm), and interslice variation was 0.89-1.21 μm. These potential variations in section thickness should be kept in mind whenever working with quantitative WBARG. (author)

A Comparative Study on Wear Properties of As Cast, Cast Aged and Forge Aged A356 Alloy with Addition of Grain Refiner and/or Modifier

Directory of Open Access Journals (Sweden)

D.G. Mallapur

2015-03-01

Full Text Available In the present work, a comparative wear behavior study of three categories of materials viz, as cast, cast aged (casting followed by T6 and forge aged (forging followed by T6 has been investigated. Neither melt treatment nor solid state processing (like aging and forging seems to be altering the wear behavior of the materials drastically. Cast aged A356 materials exhibit higher wear resistance compared to as cast and forge aged A356 materials. Further, it was observed that cast aged samples register lower coefficient of friction compared to other samples. It is also noted that the difference in wear behavior is revealed only at conditions of higher load, higher speed and longer sliding distance of testing. At lower regimes the difference is marginal. Among cast aged samples, ones treated with combined addition exhibit better wear resistance compared to other materials. Samples treated with combined addition register lowest coefficient of friction followed by samples treated with Sr, those with B, those with Ti and untreated ones. Abrasive wear mechanism is found to be operative in the regime of higher loading and higher velocity of sliding. Adhesive wear mechanism seems to be dominating the wear process at the lower regime of load and velocity of sliding.

Optical histology: a method to visualize microvasculature in thick tissue sections of mouse brain.

Directory of Open Access Journals (Sweden)

Austin J Moy

Full Text Available The microvasculature is the network of blood vessels involved in delivering nutrients and gases necessary for tissue survival. Study of the microvasculature often involves immunohistological methods. While useful for visualizing microvasculature at the µm scale in specific regions of interest, immunohistology is not well suited to visualize the global microvascular architecture in an organ. Hence, use of immunohistology precludes visualization of the entire microvasculature of an organ, and thus impedes study of global changes in the microvasculature that occur in concert with changes in tissue due to various disease states. Therefore, there is a critical need for a simple, relatively rapid technique that will facilitate visualization of the microvascular network of an entire tissue.The systemic vasculature of a mouse is stained with the fluorescent lipophilic dye DiI using a method called "vessel painting". The brain, or other organ of interest, is harvested and fixed in 4% paraformaldehyde. The organ is then sliced into 1 mm sections and optically cleared, or made transparent, using FocusClear, a proprietary optical clearing agent. After optical clearing, the DiI-labeled tissue microvasculature is imaged using confocal fluorescence microscopy and adjacent image stacks tiled together to produce a depth-encoded map of the microvasculature in the tissue slice. We demonstrated that the use of optical clearing enhances both the tissue imaging depth and the estimate of the vascular density. Using our "optical histology" technique, we visualized microvasculature in the mouse brain to a depth of 850 µm.Presented here are maps of the microvasculature in 1 mm thick slices of mouse brain. Using combined optical clearing and optical imaging techniques, we devised a methodology to enhance the visualization of the microvasculature in thick tissues. We believe this technique could potentially be used to generate a three-dimensional map of the

On the quench sensitivity of 7010 aluminum alloy forgings in the overaged condition

Energy Technology Data Exchange (ETDEWEB)

Tiryakioğlu, Murat, E-mail: m.tiryakioglu@unf.edu [School of Engineering, University of North Florida, Jacksonville, FL 32224 (United States); Robinson, Jeremy S. [Department of Mechanical, Aeronautical and Biomedical Engineering, University of Limerick, Limerick (Ireland); Eason, Paul D. [School of Engineering, University of North Florida, Jacksonville, FL 32224 (United States)

2014-11-17

The quench sensitivity of an overaged 7010 alloy forging was characterized by tensile and Vickers hardness tests, as well as scanning electron microscopy. Longitudinal tensile specimens, excised from a rectilinear open die forging were cooled from the solution treatment temperature following thirty-two different cooling paths including interrupted and delayed quenches. SEM analysis of the microstructure showed that quench precipitates were (i) Al{sub 2}CuMg (S) which nucleated heterogeneously on grain boundaries and (ii) Mg(Zn,Cu,Al){sub 2} (η) on grain boundaries, dispersoid bands, subgrain boundaries as well as in the aluminum matrix. The quench sensitivity of the alloy's yield strength and Vickers hardness was modeled simultaneously by quadruple-C curves, using an improved methodology for Quench Factor Analysis. The four C-curves used in the model represented loss of solute by (i) precipitation of S on grain boundaries, and precipitation of η (ii) on grain boundaries and dispersoid bands, (iii) on subgrain boundaries and (iv) in the matrix. The model yielded coefficient of determination (R{sup 2}) values of 0.967 and 0.974 for yield strength and Vickers hardness, respectively. The model and the implications of the results are discussed in this paper.

On the Effects of Hot Forging and Hot Rolling on the Microstructural Development and Mechanical Response of a Biocompatible Ti Alloy

Science.gov (United States)

Okazaki, Yoshimitsu

2012-01-01

Zr, Nb, and Ta as alloying elements for Ti alloys are important for attaining superior corrosion resistance and biocompatibility in the long term. However, note that the addition of excess Nb and Ta to Ti alloys leads to higher manufacturing cost. To develop low-cost manufacturing processes, the effects of hot-forging and continuous-hot-rolling conditions on the microstructure, mechanical properties, hot forgeability, and fatigue strength of Ti-15Zr-4Nb-4Ta alloy were investigated. The temperature dependences with a temperature difference (ΔT) from β-transus temperature (Tβ) for the volume fraction of the α- and β-phases were almost the same for both Ti-15Zr-4Nb-4Ta and Ti-6Al-4V alloys. In the α-β-forged Ti-15Zr-4Nb-4Ta alloy, a fine granular α-phase structure containing a fine granular β-phase at grain boundaries of an equiaxed α-phase was observed. The Ti-15Zr-4Nb-4Ta alloy billet forged at Tβ-(30 to 50) °C exhibited high strength and excellent ductility. The effects of forging ratio on mechanical strength and ductility were small at a forging ratio of more than 3. The maximum strength (σmax) markedly increased with decreasing testing temperature below Tβ. The reduction in area (R.A.) value slowly decreased with decreasing testing temperature below Tβ. The temperature dependences of σmax for the Ti-15Zr-4Nb-4Ta and Ti-6Al-4V alloys show the same tendency and might be caused by the temperature difference (ΔT) from Tβ. It was clarified that Ti-15Zr-4Nb-4Ta alloy could be manufactured using the same manufacturing process as for previously approved Ti-6Al-4V alloy, taking into account the difference (ΔT) between Tβ and heat treatment temperature. Also, the manufacturing equivalency of Ti-15Zr-4Nb-4Ta alloy to obtain marketing approval of implants was established. Thus, it was concluded that continuous hot rolling is useful for manufacturing α-β-type Ti alloy.

76 FR 24856 - Heavy Forged Hand Tools (i.e., Axes & Adzes, Bars & Wedges, Hammers & Sledges, and Picks...

Science.gov (United States)

2011-05-03

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-803] Heavy Forged Hand Tools (i.e... Administration, International Trade Administration, Department of Commerce. SUMMARY: On January 3, 2011, the Department of Commerce (``Department'') initiated a sunset review of the antidumping duty orders on heavy...

Development of seamless forged pipe and fitting for BWR recirculation loop piping with improved resistance to intergranular stress corrosion cracking

International Nuclear Information System (INIS)

Ohnishi, Keizo; Tsukada, Hisashi; Kobayashi, Masayoshi; Iwadate, Tadao; Ono, Shinichi

1981-01-01

As a primary remedy for IGSCC of primary loop piping, especially Recirculation Loop Piping of BWR, extra low carbon stainless steel with high nitrogen content has become to be used. While, in order to make In-service Inspection easier and complete, new design of piping which decrease both number and total length of weld line has been considered. Japan Steel Works has developed the research on large size seamless forged pipe and fitting made from high nitrogen extra low carbon 316 stainless steel. This paper describes the key points of manufacturing technology as well as the material properties, especially strength and intergranular-corrosion and intergranular- stress-corrosion-cracking-resistivities of these forged pipe and fitting. (author)

Model-based cartilage thickness measurement in the submillimeter range

International Nuclear Information System (INIS)

Streekstra, G. J.; Strackee, S. D.; Maas, M.; Wee, R. ter; Venema, H. W.

2007-01-01

Current methods of image-based thickness measurement in thin sheet structures utilize second derivative zero crossings to locate the layer boundaries. It is generally acknowledged that the nonzero width of the point spread function (PSF) limits the accuracy of this measurement procedure. We propose a model-based method that strongly reduces PSF-induced bias by incorporating the PSF into the thickness estimation method. We estimated the bias in thickness measurements in simulated thin sheet images as obtained from second derivative zero crossings. To gain insight into the range of sheet thickness where our method is expected to yield improved results, sheet thickness was varied between 0.15 and 1.2 mm with an assumed PSF as present in the high-resolution modes of current computed tomography (CT) scanners [full width at half maximum (FWHM) 0.5-0.8 mm]. Our model-based method was evaluated in practice by measuring layer thickness from CT images of a phantom mimicking two parallel cartilage layers in an arthrography procedure. CT arthrography images of cadaver wrists were also evaluated, and thickness estimates were compared to those obtained from high-resolution anatomical sections that served as a reference. The thickness estimates from the simulated images reveal that the method based on second derivative zero crossings shows considerable bias for layers in the submillimeter range. This bias is negligible for sheet thickness larger than 1 mm, where the size of the sheet is more than twice the FWHM of the PSF but can be as large as 0.2 mm for a 0.5 mm sheet. The results of the phantom experiments show that the bias is effectively reduced by our method. The deviations from the true thickness, due to random fluctuations induced by quantum noise in the CT images, are of the order of 3% for a standard wrist imaging protocol. In the wrist the submillimeter thickness estimates from the CT arthrography images correspond within 10% to those estimated from the anatomical

Mechanical properties of Zr-2.5Nb pressure tube material manufactured employing forging routes for PHWR700 - Part 1: tensile behavior

International Nuclear Information System (INIS)

Bind, A.K.; Singh, R.N.; Sunil, Saurav; Chakravartty, J.K.; Ghosh, Agnish; Dhandharia, Priyesh; More, Nitin S.; Vijayakumar, S.; Chhatre, A.G.

2012-01-01

Tensile properties of Zr-2.5Nb alloy tubes produced employing forging to break the cast structure were evaluated by carrying out uni-axial tension test at temperatures between 25 and 325 degC and under strain-rate of 1.075 x 10 -4 /s for both longitudinal and transverse specimens. Both strength and elongation values were comparable for the samples obtained from front and back end of the tube. Transverse samples showed higher strength and lower uniform elongation values as compared to longitudinal samples. The yield strength of double forged material at 25 degC is higher than the PHWR700 specification of a maximum value of 586 MPa. (author)

The effects of microstructure on the temper embrittlement susceptibility of a 2 1/4Cr1Mo forging

International Nuclear Information System (INIS)

Gage, G.; Edwards, B.C.; Hudson, J.A.

This paper describes the results of a detailed metallurgical assessment of the microstructural stability and temper embrittlement susceptibility of a 255mm thick 2 1/4Cr1Mo steel forging which was manufactured by a process typical of that used for the tube plates of steam generator units. Ageing effects were studied over the temperature range 450-575 deg. C for times up to 20,000h. Grain boundary compositional changes were monitored using Auger Electron Spectroscopy (AES) and microstructural changes determined by both transmission electron microscopy and X-ray analysis. Brittle intergranular failure was produced in the lower shelf energy regime and AES analysis showed that this was associated with the grain boundary segregation of phosphorus. This segregation was shown to exhibit equilibrium characteristics and was consistent with that of phosphorus segregation in α-iron. Implying no significant alloy-impurity interaction. The shift in the ductile-to-brittle transition temperature was not uniquely a function of the grain boundary segregation but was shown to be dependent upon both the level of grain boundary solute segregation and the type of precipitate particles present. Heat treatment conditions which promoted the formation of M 6 C precipitates were particularly deleterious to toughness. (author)

New lubricant systems for cold and warm forging – advantages and limitations

DEFF Research Database (Denmark)

Bay, Niels

2011-01-01

. The present paper gives an overview of these efforts substituting environmentally hazardous lubricants in cold, warm and hot forging by new, more harmless lubricants. Introduction of these new lubricants, however, has some drawbacks due to lower limits of lubrication leading to risk of pick-up, poor product......The increasing focus on environmental issues and the requirements to establish solutions diminishing the impact on working environment as well as external environment has strongly motivated the efforts to develop new, environmentally friendly tribological systems for metal forming production...

The production of grain oriented lanthanum titanate (La2Ti2O7) ceramics by uniaxial hot-forging process for improved fracture toughness

International Nuclear Information System (INIS)

Ceylan, Ali

2008-01-01

The layered-structural ceramics, such as lanthanum titanate (La 2 Ti 2 O 7 ), have been known for their good electrical and optical properties at high frequencies and temperatures. However, few studies have been conducted on the mechanical properties of these ceramics. The interest in ceramic hot-forging (HF) has been greatly increased recently due to the enhancement in fracture toughness via bridging effect of oriented grains. In this study, grain oriented lanthanum titanate was produced by the hot-forging process. The characterizations of the samples were achieved by density measurement, scanning electron microscopy (SEM), optical microscopy, X-ray diffraction (XRD), Vickers indentation and three-point bending test. According to X-ray diffraction patterns, the orientation factor (f) was found to be 0.73 for certain hot-forging conditions resulting an improved fracture toughness. The improved fracture toughness of La 2 Ti 2 O 7 (3.2 MPa m 1/2 ) reached to the value of monolithic alumina (Al 2 O 3 ) between 3 and 4 MPa m 1/2

Carotid intima-media thickness and osteoporosis in postmenopausal women: a cross-sectional study.

Science.gov (United States)

Sothornwit, J; Somboonporn, W; Soontrapa, S; Kaewrudee, S; Wongwiwatchai, J; Soontrapa, S

2018-03-09

To explore the difference in carotid intima-media thickness (CIMT) between postmenopausal women with and without osteoporosis and the risk of elevated CIMT and plaque presentation. A cross-sectional study was conducted including 46 postmenopausal women with osteoporosis and 45 non-osteoporotic postmenopausal women. CIMT was measured using B-mode ultrasound. There was no statistically significant difference in mean CIMT between postmenopausal women with osteoporosis and those without osteoporosis (p > 0.05). Risk for elevated CIMT in the osteoporosis group was comparable to that of the non-osteoporosis group (adjusted odds ratio = 0.844; 95% confidence interval 0.11-6.45). The risk for the presence of plaque was three times higher in osteoporotic women than in normal individuals. However, after adjusting for age and underlying diseases that would predispose the women to cardiovascular disease, there was no significant difference in terms of presence of plaque between the two groups (adjusted odds ratio = 0.844; 95% confidence interval 0.11-6.45). There was no difference in mean CIMT between postmenopausal women with and without osteoporosis. Risk of elevated CIMT in postmenopausal women with osteoporosis was comparable to that of postmenopausal women without osteoporosis. There was no significant difference between the two groups in terms of the presence of plaque.

Development of a 3D Finite Element code for Forging - An overview of the Brite/Euram project EFFORTS

DEFF Research Database (Denmark)

Bay, Niels; Andreasen, Jan Lasson; Olsson, David Dam

2001-01-01

The present paper presents an overview of the Brite/EuRam project EFFORTS (Enhanced Framework for FOrging design using Reliable Three-dimensional Simulation). A short description is given of methodologies developed including improvements of the numerical analysis, establishment of new constitutive...

The investigation of crimes refering to forgery of documents and possession of forged documents

OpenAIRE

Kotovienė, Danutė

2011-01-01

THE INVESTIGATION OF CRIMES REFERING TO FORGERY OF DOCUMENTS AND POSSESSION OF FORGED DOCUMENTS Constantly improving informational technologies more and more get into our daily routine: nowadays it is widely spread internet payments, purchases, signing on-line agreements using electronic signatures. However, paper documents or other made of appropriate materials, which have material evidence, still have a very significant impact on our life. Its convey different aspects of states’ public work...

2017 Status report-Tritium aging studies on stainless steel: Effect of hydrogen, tritium and decay helium on the fracture-toughness properties of stem, cup and block forgings

Energy Technology Data Exchange (ETDEWEB)

Morgan, Michael J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-06-28

The materials of construction of tritium reservoirs are forged stainless steels. During service, the structural properties of the stainless steel change over time because of the diffusion of tritium into the reservoir wall and its radioactive decay to helium-3. This aging effect can cause cracks to initiate and grow which could result in a tritium leak or delayed failure of a tritium reservoir. Numerous factors affect the tendency for crack formation and propagation and are being investigated in this program. The goal of the research is to provide relevant fracture mechanics data that can be used by the design agencies in their assessments of tritium reservoir structural integrity. In this status report, new experimental results are presented on the effects of tritium and decay helium on the cracking properties of specimens taken from actual tritium reservoir forgings instead of the experimental forgings of past programs. The properties measured are more representative of actual reservoir properties because the microstructure of the specimens tested are more like that of the actual tritium reservoirs. The program was designed to measure the effects of material variables on tritium compatibility and includes two stainless steels (Type 304L and 316L stainless steel), multiple yield strengths (360-500 MPa), and multiple forging shapes (Stem, Cup, and Block).

Rotating disk electrodes to assess river biofilm thickness and elasticity.

Science.gov (United States)

Boulêtreau, Stéphanie; Charcosset, Jean-Yves; Gamby, Jean; Lyautey, Emilie; Mastrorillo, Sylvain; Azémar, Frédéric; Moulin, Frédéric; Tribollet, Bernard; Garabetian, Frédéric

2011-01-01

The present study examined the relevance of an electrochemical method based on a rotating disk electrode (RDE) to assess river biofilm thickness and elasticity. An in situ colonisation experiment in the River Garonne (France) in August 2009 sought to obtain natural river biofilms exhibiting differentiated architecture. A constricted pipe providing two contrasted flow conditions (about 0.1 and 0.45 m s(-1) in inflow and constricted sections respectively) and containing 24 RDE was immersed in the river for 21 days. Biofilm thickness and elasticity were quantified using an electrochemical assay on 7 and 21 days old RDE-grown biofilms (t(7) and t(21), respectively). Biofilm thickness was affected by colonisation length and flow conditions and ranged from 36 ± 15 μm (mean ± standard deviation, n = 6) in the fast flow section at t(7) to 340 ± 140 μm (n = 3) in the slow flow section at t(21). Comparing the electrochemical signal to stereomicroscopic estimates of biofilms thickness indicated that the method consistently allowed (i) to detect early biofilm colonisation in the river and (ii) to measure biofilm thickness of up to a few hundred μm. Biofilm elasticity, i.e. biofilm squeeze by hydrodynamic constraint, was significantly higher in the slow (1300 ± 480 μm rpm(1/2), n = 8) than in the fast flow sections (790 ± 350 μm rpm(1/2), n = 11). Diatom and bacterial density, and biofilm-covered RDE surface analyses (i) confirmed that microbial accrual resulted in biofilm formation on the RDE surface, and (ii) indicated that thickness and elasticity represent useful integrative parameters of biofilm architecture that could be measured on natural river assemblages using the proposed electrochemical method. Copyright © 2010 Elsevier Ltd. All rights reserved.

Comparison of removed dentin thickness with hand and rotary instruments

Science.gov (United States)

Shahriari, Shahriar; Abedi, Hasan; Hashemi, Mahdi; Jalalzadeh, Seyed Mohsen

2009-01-01

INTRODUCTION: The aim of this study was to evaluate the amount of dentine removed after canal preparation using stainless steel (SS) hand instruments or rotary ProFile instruments. MATERIALS AND METHODS: Thirty-six extracted human teeth with root canal curvatures less than 30º were embedded in clear polyester resin. The roots were cut horizontally at apical 2, 4 and 7 mm. Dentin thickness was measured at each section and the sections were accurately reassembled using a muffle. Root canals were randomly prepared by SS hand instruments or rotary ProFile instruments. Root sections were again separated, and the remaining dentin thickness was measured. Mann-Whitney U and t tests were performed for analytic comparison of the results. RESULTS: The thickness of removed dentin was significantly different between the two used methods (Pinstrumentation group (Protary instrumentation prepares root canals with a greater conservation of tooth structure. PMID:23940489

Microstructure evolution of superalloy for large exhaust valve during hot forging

International Nuclear Information System (INIS)

Jeong, H.S.; Cho, J.R.; Park, H.C.

2004-01-01

The nickel-based alloy Nimonic 80A possesses strength, and corrosion, creep and oxidation resistance at high temperature. These products are used for aerospace, marine engineering and power generation, etc. The control of forging parameters such as strain, strain rate, temperature and holding time is important because the microstructure change in hot working affects the mechanical properties. It is necessary to understand the microstructure variation evolution. The microstructure change evolution occurs by recovery, recrystallization and grain growth phenomena. The dynamic recrystallization evolution has been studied in the temperature range 950-1250 deg. C and strain rate range 0.05-5s-1 using hot compression tests. The metadynamic recrystallization and grain growth evolution has been studied in the temperature range 950-1250 deg. C and strain rate range 0.05, 5s-1, holding time range 5, 10, 100, 600 sec using hot compression tests. Modeling equations are developed to represent the flow curve, recrystallized grain size, recrystallized fraction and grain growth phenomena by various tests. Parameters of modeling equation are expressed as a function of the Zener-Hollomon parameter. The modeling equation for grain growth is expressed as a function of initial grain size and holding time. The developed modeling equation was combined with thermo-viscoplastic finite element modeling to predict various microstructure change evolution during thermo mechanical processing. The predicted grain size in developed FE simulation results is compared with results obtained in various tests. In order to obtain a final microstructure and good mechanical properties in forging, the FEM would become a useful tool in the simulation of the microstructure development

Evaluation of Microstructural and Mechanical Property of Medium-sized HT9 Cladding Forged Material for Sodium-cooled Fast Reactor

International Nuclear Information System (INIS)

Kim, Jun Hwan; Lee, Kang Soo; Kim, Sung Ho; Lee, Chan Bock

2012-01-01

Microstructural and mechanical property were evaluated at the medium-sized HT9 (12Cr-1MoWV) forged steel which was considered as primary candidate for the fuel cladding in sodium-cooled fast reactor (SFR). Material was forged at 1170 degrees C after the induction melting to make round bar as 160 mm diameter, 7000 mm length then the radial distribution of microstructure as well as microhardness was evaluated. The results showed that overall microstructure exhibited as ferrite-martensite structure, where small amount (2-3%) of delta ferrite was formed throughout the specimen and maximum 15% of transformed ferrite was formed at the center, where it gradually decreased toward the radial direction. Sensitivity analysis of the cooling curve and Time-Temperature-Transformation (TTT) diagram revealed that formation of transformed ferrite could be avoided when the diameter was decreased down to 120 mm.

Automatic measuring system of zirconium thickness for zirconium liner cladding tubes

International Nuclear Information System (INIS)

Matsui, K.; Yamaguchi, H.; Hiroshima, T.; Sakamoto, T.; Murayama, R.

1985-01-01

An automatic system of pure zirconium liner thickness for zirconium-zircaloy cladding tubes has been successfully developed. The system consists of three parts. (1) An ultrasonic thickness measuring method for mother tubes before cold rolling. (2) An electromagnetic thickness measuring method for the manufactured tubes. (3) An image processing method for the cross sectional view of the manufactured cut tube samples. In Japanese nuclear industry, zirconium-zircaloy cladding tubes have been tested in order to realize load following operation in the atomic power plant. In order to provide for the practical use in the near future, Sumitomo Metal Industries, Ltd. has been studied and established the practical manufacturing process of the zirconium liner cladding tubes. The zirconium-liner cladding tube is a duplex tube comprising an inner layer of pure zirconium bonded to zircaloy metallurgically. The thickness of the pure zirconium is about 10 % of the total wall thickness. Several types of the automatic thickness measuring methods have been investigated instead of the usual microscopic viewing method in which the liner thickness is measured by the microscopic cross sectional view of the cut tube samples

Geologic thickness data: Candidate repository horizons

International Nuclear Information System (INIS)

Cross, R.W.; Fairchild, K.R.

1985-01-01

This data package contains information on the thickness of the Umtanum, McCoy Canyon, Cohassett, and Rocky Coulee flows and their intraflow structures in 20 boreholes and 2 surface sections in the Pasco Basin. Thickness data are for total flow, flow top, entablature, and colonnade (or just flow top and dense interior in some cases). Summary figures which contain descriptions and footages are included. SD-BWI-DP-011, Rev. 2 replaces SD-BWI-DP-011, Rev. A-0 in its entirety. (Rev. A-0 replaced Rev. 0-0.) 5 refs

Forging Alliances with Protection and Advocacy Systems: A Training Manual for Parents of Children with Emotional Disorders.

Science.gov (United States)

Petr, Christopher G.

This manual is intended to be used in conjunction with a 1-day training workshop to help parents of children with emotional disorders establish working alliances with protection and advocacy agencies for people with mental illness (PAMIs). The workshop prepares parents for developing specific plans for forging alliances with the state PAMI. The…

Progressive forging. Alternate process to little capacities presses; Forjamento progressivo. Processo alternativo para prensas de pequena capacidade

Energy Technology Data Exchange (ETDEWEB)

Schaeffer, Lirio; Brito, Alberto M.G. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Dept. de Metalurgia

1986-12-31

This work presents several alternatives and possibilities to incremental forging. Some experimental results are presented.Lead was used to simulate the material flow. The influence of the sample geometry and the best way to perform further experiences with titanium alloy Ti A16 V4 were analyzed. 11 figs., 2 tabs., 9 refs.

The Use of Intravital Two-Photon and Thick Section Confocal Imaging to Analyze B Lymphocyte Trafficking in Lymph Nodes and Spleen.

Science.gov (United States)

Park, Chung; Hwang, Il-Young; Kehrl, John H

2018-01-01

Intravital two-photon laser scanning microscopy (TP-LSM) has allowed the direct observation of immune cells in intact organs of living animals. In the B cell biology field TP-LSM has detailed the movement of B cells in high endothelial venules and during their transmigration into lymph organs; described the movement and positioning of B cells within lymphoid organs; outlined the mechanisms by which antigen is delivered to B cells; observed B cell interacting with T cells, other cell types, and even with pathogens; and delineated the egress of B cells from the lymph node (LN) parenchyma into the efferent lymphatics. As the quality of TP-LSM improves and as new fluorescent probes become available additional insights into B cell behavior and function await new investigations. Yet intravital TP-LSM has some disadvantages including a lower resolution than standard confocal microscopy, a narrow imaging window, and a shallow depth of imaging. We have found that supplementing intravital TP-LSM with conventional confocal microscopy using thick LN sections helps to overcome some of these shortcomings. Here, we describe procedures for visualizing the behavior and trafficking of fluorescently labeled, adoptively transferred antigen-activated B cells within the inguinal LN of live mice using two-photon microscopy. Also, we introduce procedures for fixed thick section imaging using standard confocal microscopy, which allows imaging of fluorescently labeled cells deep in the LN cortex and in the spleen with high resolution.

Forging Fluorine‐Containing Quaternary Stereocenters by a Light‐Driven Organocatalytic Aldol Desymmetrization Process

Science.gov (United States)

Cuadros, Sara; Dell'Amico, Luca

2017-01-01

Abstract Reported herein is a light‐triggered organocatalytic strategy for the desymmetrization of achiral 2‐fluoro‐substituted cyclopentane‐1,3‐diketones. The chemistry is based on an intermolecular aldol reaction of photochemically generated hydroxy‐o‐quinodimethanes and simultaneously forges two adjacent fully substituted carbon stereocenters, with one bearing a stereogenic carbon–fluorine unit. The method uses readily available substrates, a simple chiral organocatalyst, and mild reaction conditions to afford an array of highly functionalized chiral 2‐fluoro‐3‐hydroxycyclopentanones. PMID:28746742

Backward can extrusion with conical,rotating punch as a cold forging tribology test

DEFF Research Database (Denmark)

Ceron, Ermanno; Bay, Niels; Tetsuo, A.

2011-01-01

with an analysis of the sliding velocity distribution along the punch nose. The latter is determined by FE analysis of the test. Results show friction stress for unalloyed low C-steel provided with different types of lubricants, e.g. phosphate coating plus soap, phosphate coating plus MoS2 and single bathe...... lubrication with PULS. The new test is so severe, that it is possible to break down the best lubrication systems for cold forging, such as phosphate coating plus soap and MoS2....

Mathematical Model of Stress-Strain State of Curved Tube of Non-Circular Cross-Section with Account of Technological Wall Thickness Variation

Science.gov (United States)

Pirogov, S. P.; Ustinov, N. N.; Smolin, N. I.

2018-05-01

A mathematical model of the stress-strain state of a curved tube of a non-circular cross-section is presented, taking into account the technological wall thickness variation. On the basis of the semi-membrane shell theory, a system of linear differential equations describing the deformation of a tube under the effect of pressure is obtained. To solve the boundary value problem, the method of shooting is applied. The adequacy of the proposed mathematical model is verified by comparison with the experimental data and the results of the calculation of tubes by the energy method.

Self-heating forecasting for thick laminates testing coupons in fatigue

NARCIS (Netherlands)

Lahuerta, F.; Westphal, T.; Nijssen, R.P.L.

2012-01-01

Thick laminate sections can be found from the tip to the root in most common wind turbine blade designs. Obtaining accurate and reliable design data for thick laminates is subject of investigations. Due to the poor thermal conductivity properties of composites and the material self-heating that

An in vitro study of mesiobuccal root thickness of maxillary first molars.

Science.gov (United States)

Mohammadzadeh Akhlaghi, Nahid; Ravandoust, Yasaman; Najafi, Mohammad; Dadresanfar, Bahareh

2012-01-01

Understanding the internal anatomy of root canal system can significantly influence outcomes of root canal treatment. The aim of this in vitro study was to measure the thickness of mesiobuccal root at different levels in maxillary first molars. In this cross-sectional study, forty extracted human maxillary first molars were radiographed; accordingly, the mesial and distal root thicknesses of mesiobuccal (MB) roots were measured at four parallel horizontal levels. The samples were sectioned at the measured levels and then sections were scanned and saved in the computer. Buccal (B), Palatal (P), Mesial (M) and Distal (D) aspects of root thicknesses in single-canalled roots were measured. In two-canalled mesiobuccal roots, Distobuccal (DB) and Distopalatal (DP) aspects were evaluated alongside other measurements. Average radicular thickness in each aspect and each level was compared using ANOVA and t-test. A total of 25 had two canals and 15 had one canal in MB root. In single-canalled roots M and D aspects were the thinnest whereas in two-canalled samples, the thicknesses of DP and DB aspects were significantly less than others (Pmolar roots in order to avoid technical mishaps.

The investigation of the FM heavy forging process by the Moiré method. Part II: Consecutive reduction results

NARCIS (Netherlands)

Wang, S.L.; Cao, Q.X.

1994-01-01

In part I of this work (preceding paper), single-reduction results on the FM forging process were reported. In the work reported in this paper, the cavity closing laws of the consecutive reduction process were investigated, the appropriate turn-over and feed procedure being obtained, along with the

Effect of subcooling and wall thickness on pool boiling from downward-facing curved surfaces in water

Energy Technology Data Exchange (ETDEWEB)

El-Genk, M.S.; Glebov, A.G. [Univ. of New Mexico, Albuquerque, NM (United States)

1995-09-01

Quenching experiments were performed to investigate the effects of water subcooling and wall thickness on pool boiling from a downward-facing curved surface. Experiments used three copper sections of the same diameter (50.8 mm) and surface radius (148 mm), but different thickness (12.8, 20 and 30 mm). Local and average pool boiling curves were obtained at saturation and 5 K, 10 K, and 14 K subcooling. Water subcooling increased the maximum heat flux, but decreased the corresponding wall superheat. The minimum film boiling heat flux and the corresponding wall superheat, however, increased with increased subcooling. The maximum and minimum film boiling heat fluxes were independent of wall thickness above 20 mm and Biot Number > 0.8, indicating that boiling curves for the 20 and 30 thick sections were representative of quasi steady-state, but not those for the 12.8 mm thick section. When compared with that for a flat surface section of the same thickness, the data for the 12.8 mm thick section showed significant increases in both the maximum heat flux (from 0.21 to 0.41 MW/m{sup 2}) and the minimum film boiling heat flux (from 2 to 13 kW/m{sup 2}) and about 11.5 K and 60 K increase in the corresponding wall superheats, respectively.

Friction Stir Welding of Tapered Thickness Welds Using an Adjustable Pin Tool

Science.gov (United States)

Adams, Glynn; Venable, Richard; Lawless, Kirby

2003-01-01

Friction stir welding (FSW) can be used for joining weld lands that vary in thickness along the length of the weld. An adjustable pin tool mechanism can be used to accomplish this in a single-pass, full-penetration weld by providing for precise changes in the pin length relative to the shoulder face during the weld process. The difficulty with this approach is in accurately adjusting the pin length to provide a consistent penetration ligament throughout the weld. The weld technique, control system, and instrumentation must account for mechanical and thermal compliances of the tooling system to conduct tapered welds successfully. In this study, a combination of static and in-situ measurements, as well as active control, is used to locate the pin accurately and maintain the desired penetration ligament. Frictional forces at the pin/shoulder interface were a source of error that affected accurate pin position. A traditional FSW pin tool design that requires a lead angle was used to join butt weld configurations that included both constant thickness and tapered sections. The pitch axis of the tooling was fixed throughout the weld; therefore, the effective lead angle in the tapered sections was restricted to within the tolerances allowed by the pin tool design. The sensitivity of the FSW process to factors such as thickness offset, joint gap, centerline offset, and taper transition offset were also studied. The joint gap and the thickness offset demonstrated the most adverse affects on the weld quality. Two separate tooling configurations were used to conduct tapered thickness welds successfully. The weld configurations included sections in which the thickness decreased along the weld, as well as sections in which the thickness increased along the weld. The data presented here include weld metallography, strength data, and process load data.

Study on Pot Forming of Induction Heater Type Rice Cookers by Forging Cast Process

Science.gov (United States)

Ohnishi, Masayuki; Yamaguchi, Mitsugi; Ohashi, Osamu

This paper describes a study result on pot fabrication by the forging cast process of stainless steel with aluminum. Rice cooked with the new bowl-shaped pot for the induction heater type rice cookers is better tasting than rice cooked with the conventional cylindrical one, due to the achievement of better heat conduction and convection. The conventional pot is made of the clad sheet, consisting of stainless steel and aluminum. However, it is rather difficult to form a bowl shape from the clad sheet, primarily due to the problem of a material spring back. The fabrication of a new type of a pot was made possible by means of the adoption of a forging cast process instead of the clad sheet. In this process, iron powder is inserted between stainless steel and aluminum in order to alleviate the large difference on the coefficient of expansion between each material. It was made clear that the application of two kinds of iron particle, namely 10 μm size powder on the stainless steel side and 44 μm on the aluminum side, enables the joints to become strong enough. The joint strength of the new pot by this fabrication process was confirmed by the tests of the shear strength and the fatigue tests together with the stress analysis.

Forging Fluorine-Containing Quaternary Stereocenters by a Light-Driven Organocatalytic Aldol Desymmetrization Process.

Science.gov (United States)

Cuadros, Sara; Dell'Amico, Luca; Melchiorre, Paolo

2017-09-18

Reported herein is a light-triggered organocatalytic strategy for the desymmetrization of achiral 2-fluoro-substituted cyclopentane-1,3-diketones. The chemistry is based on an intermolecular aldol reaction of photochemically generated hydroxy-o-quinodimethanes and simultaneously forges two adjacent fully substituted carbon stereocenters, with one bearing a stereogenic carbon-fluorine unit. The method uses readily available substrates, a simple chiral organocatalyst, and mild reaction conditions to afford an array of highly functionalized chiral 2-fluoro-3-hydroxycyclopentanones. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Effect of the Process Parameters on the Formability, Microstructure, and Mechanical Properties of Thin Plates Fabricated by Rheology Forging Process with Electromagnetic Stirring Method

Science.gov (United States)

Jin, Chul Kyu; Jang, Chang Hyun; Kang, Chung Gil

2014-01-01

A thin plate (150 × 150 × 1.2 mm) with embedded corrugation is fabricated using the rheoforming method. Semisolid slurry is created using the electromagnetic stirring (EMS) system, and the thin plate is made with the forging die at the 200-ton hydraulic press. The cross sections and microstructures of the slurry with and without stirring are examined. To investigate the effect of the process parameters on the formability, microstructure, and mechanical properties of thin plate the slurry is subjected to 16 types of condition for the forging experiment. The 16 types included the following conditions: Whether the EMS is applied or not, three fractions of the solid phase at 35, 45 and 55 pct; two compression velocities at 30 and 300 mm s-1; and four different compression pressures—100, 150, 200 and 250 MPa. The thin plate's formability is enhanced at higher punch velocity for compressing the slurry, and fine solid particles are uniformly distributed, which in turn, enhances the plate's mechanical properties. The pressure between 150 and 200 MPa is an appropriate condition to form thin plates. A thin plate without defects can be created when the slurry at 35 pct of the solid fraction (f s) was applied at the compression velocity of 300 mm s-1 and 150 MPa of pressure. The surface state of thin plate is excellent with 220 MPa of tensile strength and 13.5 pct of elongation. The primary particles are fine over the entire plate, and there are no liquid segregation-related defects.

Forging New, Non-traditional Partnerships Among Physicists, Teachers and Students

Energy Technology Data Exchange (ETDEWEB)

Bardeen, Marjorie [Fermilab; Adams, Mark [Illinois U., Chicago; Wayne, Mitchell [Notre Dame U.; Karmgard, Dan [Notre Dame U.; Goussiou, Anna [Washington U., Seattle

2017-05-02

The QuarkNet collaboration has forged new, nontraditional relationships among particle physicists, high school teachers and their students. QuarkNet provides professional development for teachers and creates opportunities for teachers and students to engage in particle physics data investigations and join research teams. Embedded in the U.S. particle research community, QuarkNet leverages the nature of particle physics research—the long duration of the experiments with extensive lead times, construction periods, and data collection and analysis periods. QuarkNet is patterned after the large collaborations with a central management infrastructure and a distributed workload across university- and lab-based research groups. We describe the important benefits of the QuarkNet outreach program that flow to university faculty and present successful strategies that others can adapt for use in their countries.

Forging New Cocoa Keys: The Impact of Unlocking the Cocoa Bean’s Genome on Pre-harvest Food Safety

Science.gov (United States)

Forging New Cocoa Keys: The Impact of Unlocking the Cocoa Bean’s Genome on Pre-harvest Food Safety David N. Kuhn, USDA ARS SHRS, Miami FL Sometimes it's hard to see the value and application of genomics to real world problems. How will sequencing the cacao genome affect West African farmers? Thi...

Frobenius splitting of thick flag manifolds of Kac-Moody algebras

OpenAIRE

Kato, Syu

2017-01-01

We explain that the Pl\\"ucker relations provide the defining equations of the thick flag manifold associated to a Kac-Moody algebra. This naturally transplant the result of Kumar-Mathieu-Schwede about the Frobenius splitting of thin flag manifolds to the thick case. As a consequence, we provide a description of the global sections of line bundles of a thick Schubert variety as conjectured in Kashiwara-Shimozono [Duke Math. J. 148 (2009)]. This also yields the existence of a compatible basis o...

Wall thickness of major coronary arteries in Pakistani population

International Nuclear Information System (INIS)

Ullah, Q.W.; Qamar, K.; Butt, S.A.; Butt, S.A.

2012-01-01

To measure the wall thickness of major coronary arteries in Pakistani population, through micrometry. Study design: An observational study. Place and duration of study: Combined Military Hospital Rawalpindi, Khyber Medical College Peshawar and District Headquarter Hospital, Rawalpindi, in collaboration with Departments of Anatomy and Pathology, Army Medical College Rawalpindi. The duration of study was six months with effect from September 2009 to March 2010. Material and methods: After incising pericardium, 1 mm long segments of major coronary arteries i.e. right coronary artery (RCA), left anterior descending artery (LAD) and left circumflex artery (LCX) were taken 1cm distal to their origin, from adult male cadavers of up to 40 years age. After processing for paraffin embedding, 5 mu m thick sections were prepared, mounted on glass slides and subsequently stained with Hematoxylin and Eosin (H and E) for routine histological study. Verhoeff's elastic stain was used to make the elastic lamina more prominent. Wall thickness for each section was measured through micrometry, circumferentially at eight different places along the planes at 45 deg. to each other and then their mean taken as a reading for the respective artery. Results: The total wall thickness of major coronary arteries and of the individual tunicae was less in Pakistani population. The mean thickness of RCA was 0.61 +- 0.05 mm; LAD had mean thickness of 0.55 +- 0.06 mm whereas that of LCX was 0.66 +- 0.13 mm. The mean thickness of tunica intima of RCA was noted to be 0.230 +- 0.044 mm; tunica media measured 0.205 +- 0.031 mm whereas tunica adventitia was 0.172 +- 0.023 mm thick. The mean thickness of tunica intima of LAD measured 0.156 +- 0.032 mm; tunica media was observed to be 0.224 +- 0.026 mm thick whereas the tunica adventitia was 0.170 +- 0.032 mm thick. The mean thickness of tunica intima of LCX was observed to be 0.203 +- 0.059 mm; tunica media to be 0.282 +- 0.097 mm whereas that of tunica

Forging partnerships between rural women with chronic conditions and their health care providers.

Science.gov (United States)

Cudney, Shirley; Weinert, Clarann; Kinion, Elizabeth

2011-03-01

Successful adaptation to chronic illness is enhanced by active client-health care provider partnerships. The purposes of this article are to (a) examine the health care partnership needs of western rural women with chronic illness who participated in a computer-based support and education project, (b) describe how the role of the women in the partnership can be maximized by the use of a personal health record and improving health literacy, and (c) discuss ways health care providers can enhance their role in the partnership by careful listening and creating environments conducive to forging productive client-provider partnerships.

Development and production of nuclear valves. Forging and welding. Pt. 2

International Nuclear Information System (INIS)

Bernal Castro, J.B.; Perez, J.C.; Labonia, R.N.

1987-01-01

The first part of this work deals with the obtainment of the austenitic stainless steel DIN 1.4541 (AISI 321) stabilized titanium for Atucha II nuclear valves. The second part presented herein, continued with the development process and part of the production of the bodies' forging and valves leads. This development has been also carried out in the country and a detailed set up of the process with its corresponding Inspection and Assay Program was needed. The last part of this stage has been initiated at the welding process, so it was necessary to develop specific welding procedures to qualify them and use the equipment specially applied to this requirement. The set of assays and criteria certification for the qualifications is presented. (Author)

Evaluation of various hot mix asphalt pavement thicknesses over rubblized concrete pavement.

Science.gov (United States)

2011-07-01

In 1999, the Wisconsin DOT constructed two test sections as part of a rubblized PCC pavement project on I-39 to evaluate whether : increased HMA thickness could extend the pavement system's service life. Design thicknesses of the control and test sec...

Self-heating forecasting for thick laminate specimens in fatigue

Science.gov (United States)

Lahuerta, F.; Westphal, T.; Nijssen, R. P. L.

2014-12-01

Thick laminate sections can be found from the tip to the root in most common wind turbine blade designs. Obtaining accurate and reliable design data for thick laminates is subject of investigations, which include experiments on thick laminate coupons. Due to the poor thermal conductivity properties of composites and the material self-heating that occurs during the fatigue loading, high temperature gradients may appear through the laminate thickness. In the case of thick laminates in high load regimes, the core temperature might influence the mechanical properties, leading to premature failures. In the present work a method to forecast the self-heating of thick laminates in fatigue loading is presented. The mechanical loading is related with the laminate self-heating, via the cyclic strain energy and the energy loss ratio. Based on this internal volumetric heat load a thermal model is built and solved to obtain the temperature distribution in the transient state. Based on experimental measurements of the energy loss factor for 10mm thick coupons, the method is described and the resulting predictions are compared with experimental surface temperature measurements on 10 and 30mm UD thick laminate specimens.

Evaluation of cross sections of 56Fe up to 3 GeV and integral benchmark calculation for thick target yield

International Nuclear Information System (INIS)

Yoshizawa, Nobuaki; Meigo, Shin-ichiro

2001-01-01

The neutron and proton cross sections of 56 Fe were evaluated up to 3 GeV. JENDL High Energy File of 56 Fe were developed for use in transport calculation. For neutrons, the high-energy data are merged with JENDL3.3-file. Integral benchmark calculations for thick target neutron yields (TTY) for 113 MeV and 256 MeV proton bombardment of Fe targets were performed using the evaluated libraries. Calculated TTY neutron spectra were compared with experimental data. For 113 MeV, calculated TTY at 7.5 degree underestimated in the emitted neutron energy range above 10 MeV. For 256 MeV, calculated TTY well agree with experimental data except below 10 MeV. (author)

A comparison between destructive and non-destructive techniques in determining coating thickness

Science.gov (United States)

Haider, F. I.; Suryanto; Ani, M. H.; Mahmood, M. H.

2018-01-01

Measuring coating thickness is an important part in research works related to coating applications. In general, techniques for measuring coating thickness may be divided into destructive and non-destructive methods which are commonly used depending on the applications. The objective of this study is to compare two methods measuring the coating thickness of electroplating copper coating on the austenitic stainless-steel substrate. The electroplating was carried out in a solution containing 200 g/L CuSO4, 100 g/L H2SO4 at room temperature and current of 40mA/cm2 during 20, 40, 60, 80 and 100 mins as coating periods. And the coating thickness was measured by two methods, cross sectional analysis as a destructive technique and weight gain as a non-destructive technique. The results show that at 20 mins coating time interval, the thickness measured by cross sectional method was 16.67 μm and by weight gain method was 17.37 μm, with difference of 0.7 μm and percentage error of 4.11%. This error increased to 5.27% at 100mins time interval, where the values of the thickness measured by cross sectional and weight gain were 86.33 μm and 81.9 μm respectively, and the difference was 4.43 μm. Moreover, though the weight gain method is fast and gives the indication for the termination of a coating process, information regarding the uniformity, porosity and the presence of cracks cannot be obtained. On the other hand, determining the coating thickness using destructive method will damage the sample.

Optimum schedules of difficult-to-form heat-resistant alloys forging

International Nuclear Information System (INIS)

Majzengel'ter, V.A.; Shuvalov, A.A.; Perevozov, A.S.

2000-01-01

The process of manufacturing half finished discs for hydroturbine engines from heat resistant difficulty deformed nickel, iron-nickel and cobalt alloys (EI435, EI868, VZh145-ID, EK79-ID, EK152-ID, EI826, EP648-VI) is described. The recommendations on the modes of forging the single-phase nonaging and double phase aging alloys are developed. The conclusion is made, that the first compressions of ingots shoved be accomplished by small press runs. The subsequent compressions should constituted not less than 8% during one run. The total compression of the ingot during one heating should be within the concrete alloy properties. With the purpose of obtaining uniform fine-grain structure the ingot heating during the last manufacturing cycle should be accomplished within the range of 1100-1130 deg C for the majority of heat resistant alloys [ru

Study on fluidity of squeeze cast AZ91D magnesium alloy with different wall thicknesses

Directory of Open Access Journals (Sweden)

Chen Yun

2014-03-01

Full Text Available Rectangular cross-section specimens with different section thicknesses were prepared to study the influences of pouring temperature, mould temperature and squeeze velocity on the fluidity of squeeze cast AZ91D magnesium alloy by means of orthogonal test design method. The results show that pouring temperature, mould temperature and squeeze velocity can significantly affect the fluidity of magnesium alloy specimens with wall thickness no more than 4 mm, and the pouring temperature is the most influential factor on the fluidity of specimens with wall thickness of 1, 2 and 3 mm, while mould temperature is the one for specimens with wall thickness of 4 mm. Increasing pouring temperature between 700 °C and 750 °C is beneficial to the fluidity of AZ91D magnesium alloy, and increasing mould temperature significantly enhances the filling ability of thick (3 and 4 mm section castings. The fluidity of squeeze cast magnesium alloy increases with the increase of wall thickness. It is not recommended to produce magnesium alloy casting with wall thickness of smaller than 3 mm by squeeze cast process due to the poor fluidity. The software DPS was used to generate the regression model, and linear regression equations of the fluidity of squeeze cast AZ91D with different wall thicknesses are obtained using the test results.

Reversed straining in axisymmetric compression test

DEFF Research Database (Denmark)

Arentoft, Mogens; Wanheim, Tarras; Lindegren, Maria

2005-01-01

A large group of the cold forging processes is carried out in a thick – walled container with the deformation force transmitted through a punch moving axially in the container. The work piece, being entrapped between punch and container will expand and exert a radial pressure resulting in an expa...... to simulate these conditions a reversed axisymmetrical material tester is designed and constructed. Three different materials were tested, aluminum alloy AA6082, technically pure copper (99.5%) and cold forging steel Ma8, at different temperatures found during cold forging....

CT measurement of normal pericardial thickness in adults on computed tomography

International Nuclear Information System (INIS)

Choi, Young Woo; Park, Chan Sup; Jeon, Yong Sun; Bae, In Young; Choi, Sung Gyu; Koo, Jin Hoe; Chung, Won Kyun

1998-01-01

The purpose of this study was to establish, using computed tomography, the normal thickness of the pericardium in adults. Materials and Methods: CT scans of 50 patients, including sections through the level of the heart, were reviewed. Patients were excluded if there were any suspicions of pericardial abnormality such as infectious or neoplastic diseases. Twenty-four of the 50 were men and 26 were women; their mean age was 47.0(range,18-76) years. We measured pericardial thickness at the level of the right ventricle, interventricular septum and left ventricle, and also compared pericardial thickness in terms of age and sex. Results: In all patients, the pericardium was observed in the right ventricular region; in 41 (82%) at the interventricular septum; and in 41 (82%) along the left ventricle. The mean thickness of normal pericardium at the level of the right ventricle, interventricular septum, and left ventricle was 1.8 mm ± 0.5 mm, 1.8 mm ± 0.4 mm, and 1.7 mm ± 0.5 mm, respectively. No statistically significant correlation was apparent between pericardial thickness and age group (p > 0.63, ANOVA test). Mean pericardial thickness was 1.9 mm ± 0.6 mm in males and 1.7 mm ± 0.4 mm in females; thus, no statistically significant correlation was apparent between pericardial thickness and sex (p >0.29, Student's t-test). Conclusion: The pericardium was best visualized in sections through the right ventricle.The mean thickness of normal pericardium was 1.8 mm ± 0.5 mm and pericardial thickness did not differ according to age or sex

Full reflector thickness and isolation thickness on neutron transport

International Nuclear Information System (INIS)

Sakai, Tomohiro; Naito, Yoshitaka; Komuro, Yuichi.

1988-08-01

A method to determine ''full reflector thickness'' and ''isolation thickness'', which is utilized for criticality safety evaluation on nuclear fuel facilities, was proposed in this paper. Firstly, a calculation was tryed to obtain the two kinds of thicknesses from the result of criticality calculations for a specific case. Then, two simple equations which calculates the two kinds of thicknesses were made from the relation between reflector (or isolator) thickness and k eff , and one-group diffusion theory. Finally, we proposed a new method to determine the thicknesses. From the method we proposed, ''full reflector thickness'' and ''isolation thickness'' can be obtain using the equations and migration length of the reflector (or isolator) and infinite and effective multiplication factor of the fuel. (author)

Optically Sectioned Imaging of Microvasculature of In-Vivo and Ex-Vivo Thick Tissue Models with Speckle-illumination HiLo Microscopy and HiLo Image Processing Implementation in MATLAB Architecture

Science.gov (United States)

Suen, Ricky Wai

The work described in this thesis covers the conversion of HiLo image processing into MATLAB architecture and the use of speckle-illumination HiLo microscopy for use of ex-vivo and in-vivo imaging of thick tissue models. HiLo microscopy is a wide-field fluorescence imaging technique and has been demonstrated to produce optically sectioned images comparable to confocal in thin samples. The imaging technique was developed by Jerome Mertz and the Boston University Biomicroscopy Lab and has been implemented in our lab as a stand-alone optical setup and a modification to a conventional fluorescence microscope. Speckle-illumination HiLo microscopy combines two images taken under speckle-illumination and standard uniform-illumination to generate an optically sectioned image that reject out-of-focus fluorescence. The evaluated speckle contrast in the images is used as a weighting function where elements that move out-of-focus have a speckle contrast that decays to zero. The experiments shown here demonstrate the capability of our HiLo microscopes to produce optically-sectioned images of the microvasculature of ex-vivo and in-vivo thick tissue models. The HiLo microscope were used to image the microvasculature of ex-vivo mouse heart sections prepared for optical histology and the microvasculature of in-vivo rodent dorsal window chamber models. Studies in label-free surface profiling with HiLo microscopy is also presented.

A Forging Hardness Dispersion Effect on the Energy Consumption of Machining

Directory of Open Access Journals (Sweden)

L. D. Mal'kova

2015-01-01

Full Text Available The aim of the work is to evaluate a hardness dispersion of forgings to be further machined, and analyse the impact of this dispersion on the resulting power consumption when cutting.The paper studies the hardness values of three kinds of parts for automotive manufacturing. Sample of each part was n = 100 pieces. Analysis of measurements showed that 46% - 93% of parts meet requirements for a range defined by the work-piece working drawing. It was found that hardness of one batch of forgings is under dispersion, which distribution is governed by the normal law.The work provides calculations for machining the external cylindrical surfaces of the considered parts. In the context of calculating are adopted parameters of the enterprise-processing rate. It is found that power consumption of machining because of the dispersion values of the work-piece hardness is a function of the random BH variable and it itself is a random variable. Two types of samples are considered, namely: the full sample and that of the values that meet requirements for hardness. The coefficient of variation for samples that meet the technical requirements for hardness is lower than for the full samples, so their average value is more reliable characteristic of a set. It was also found that to ensure a reliable prediction of power consumption in designing the manufacturing processes it is necessary to reduce a tolerance range of workpiece hardness to the limit.The work gives a comparative evaluation of electric power consumption per unit cylindrical surface of the parts under consideration. A relative change in the electric power consumed at the minimum and maximum levels of the hardness value was introduced as an evaluation criterion. It is found that with changing hardness of machined work-pieces within the tolerance, the change in power consumption in machining the unit surface reaches 16% while in the case its being out of the specified range it does 47%.

Comparison of Lateral Abdominal Muscle Thickness and Cross Sectional Area of Multifidus in Adolescent Soccer Players with and without Low Back Pain: A Case Control Study.

Science.gov (United States)

Noormohammadpour, Pardis; Hosseini Khezri, Alireza; Linek, Paweł; Mansournia, Mohammad Ali; Hassannejad, Alireza; Younesian, Ali; Farahbakhsh, Farzin; Kordi, Ramin

2016-12-01

Low back pain (LBP) is a common complaint amongst adolescent athletes. While different studies have shown association between LBP and trunk muscle thickness in the general population, few articles have studied it in adolescent athletes. The aim of this study is to compare lateral abdominal muscle thickness and function, and cross sectional area (CSA) of lumbar multifidus (LM) in adolescent soccer players with and without LBP. In total, 28 adolescent soccer players with and without LBP, from the premier league participated in this study. The thickness of external oblique, internal oblique and transversus abdominis and the CSA of the LM muscles at L4 level on both sides were measured at rest and contraction via ultrasound imaging (USI). In addition, leg length discrepancy, hamstring flexibility, active lumbar forward flexion, and isometric muscle endurance of trunk extensors were measured in both groups. (study design/setting: case control study). The mean (SD) age in LBP group and non-LBP group were 14.0 (1.1) and 14.1 (0.9) years, respectively. There was no significant difference in baseline characteristics of participants between groups. Findings showed no significant difference between LBP and non-LBP groups comparing all measured variables. The data obtained support that there is not a correlation between abdominal muscle thickness and CSA of the lumbar multifidi and LBP in adolescent soccer players. These findings suggest that other factors rather than the thickness of deep trunk muscles may play a more significant role in the etiology of LBP in adolescent soccer players.

An Assessment of the Ductile Fracture Behaviour of Hot Isostatically Pressed and Forged 304L Stainless Steel

OpenAIRE

Cooper, Adam; Smith, R. J.; Sherry, Andrew

2017-01-01

Type 300 austenitic stainless steel manufactured by hot isostatic pressing (HIP) has recently been shown to exhibit subtly different fracture behavior from that of equivalent graded forged steel, whereby the oxygen remaining in the component after HIP manifests itself in the austenite matrix as nonmetallic oxide inclusions. These inclusions facilitate fracture by acting as nucleation sites for the initiation, growth, and coalescence of microvoids in the plastically deforming austenite matrix....

The Effect of Forging Variables on the Supersolvus Heat-Treatment Response of Powder-Metallurgy Nickel-Base Superalloys

Science.gov (United States)

2014-12-01

AFRL-RX-WP-JA-2015-0160 THE EFFECT OF FORGING VARIABLES ON THE SUPERSOLVUS HEAT-TREATMENT RESPONSE OF POWDER - METALLURGY NICKEL-BASE SUPERALLOYS... POWDER - METALLURGY NICKEL- BASE SUPERALLOYS (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6. AUTHOR...treatment (SSHT) of two powder - metallurgy , gamma–gamma prime superalloys, IN-100 and LSHR, was established. For this purpose, isothermal, hot

Effect of nickel addition on mechanical properties of powder forged Fe-Cu-C

Science.gov (United States)

Archana Barla, Nikki

2018-03-01

Fe-Cu-C system is very popular in P/M industry for its good compressibility and dimensional stability with high strength. Fe-Cu-C is a structural material and is used where high strength with high hardness is required. The composition of powder metallurgy steel plays a vital role in the microstructure and physical properties of the sintered component. Fe-2Cu-0.7C-Ni alloy with varying nickel composition (0%, 0.5%, 1.0%, 1.5%, 2.0%, and 3.0%) wt. % was prepared by powder metallurgy (P/M) sinter forging process. The present work discuss the effect of varying nickel content on microstructure and mechanical properties.

α-Linalool - a marker compound of forged/synthetic sweet basil (Ocimum basilicum L.) essential oils.

Science.gov (United States)

Radulović, Niko S; Blagojević, Polina D; Miltojević, Ana B

2013-10-01

Ocimum basilicum L. (sweet basil) is known to occur as several chemotypes or cultivars that differ in their essential oil composition. The surprising discovery of 3,7-dimethylocta-1,7-dien-3-ol, the rare α isomer of the well-known monoterpene alcohol β-linalool (3,7-dimethylocta-1,6-dien-3-ol), in samples of Serbian basil oil provoked an investigation of the origin of α-linalool in these samples. Three scenarios were considered, namely (a) the existence of a new natural chemotype, (b) an artefactual formation during the isolation procedure and (c) the case of a synthetic/forged oil. Noteworthy amounts (15.1-16.9%) of pure α-linalool were isolated from a commercial sample of basil oil, and detailed spectral analyses (MS, IR, (1) H and (13) C NMR) unequivocally confirmed its identity. The analysis by GC and GC/MS of an additional 20 samples of different O. basilicum oils commercially available on the Serbian market or isolated from plant material cultivated in Serbia resulted in the identification of 149 compounds. The obtained compositional data were compared using multivariate statistical analysis to reveal the possible existence of a new basil chemotype. The results of the chemical and statistical analyses give more pro arguments for the synthetic/forged oil hypothesis and suggest that α-linalool could be used as a marker compound of such O. basilicum oils. © 2013 Society of Chemical Industry.

The evolution of microtexture and macrotexture during subtransus forging of Ti-10V-2Fe-3Al

International Nuclear Information System (INIS)

Raghunathan, S.L.; Dashwood, R.J.; Jackson, M.; Vogel, S.C.; Dye, D.

2008-01-01

The macrotextures and microtextures produced during α+β forging of Ti-10V-2Fe-3Al were characterised using neutron, in situ synchrotron X-ray and ex situ electron backscatter diffraction (EBSD). The EBSD analysis showed that the measured misorientation distributions at a strain of 0.8 and strain rates of 0.1 and 0.01s -1 were similar, with an average misorientation of 2.2 deg. During forging, the moderate cube macrotexture inherited from the parent material was converted into a moderate fibre texture, with the major change occurring between strains of 0.4 and 0.6. The synchrotron diffraction studies allowed the orientation evolution of individual grains to be characterised. At the highest strain rate of 0.1s -1 , this indicated a change in behaviour from dispersion of the crystal mosaic (peak angular spread) at low strains, to convergence of the crystal mosaic at larger strains. At lower strain rates, only convergence of the crystal mosaic was observed. It is suggested that these results indicate a change in mechanism between deformation-controlled behaviour during the early stages of deformation and a strain rate of 0.1s -1 and diffusional, recovery-controlled behaviour at lower strain rates and higher strains

Interocular Symmetry in Macular Choroidal Thickness in Children

Directory of Open Access Journals (Sweden)

Christiane Al-Haddad

2014-01-01

Full Text Available Objective. To report interocular differences in choroidal thickness in children using spectral domain optical coherence tomography (SD-OCT and correlate findings with biometric data. Methods. This observational cross-sectional study included 91 (182 eyes healthy children aged 6 to 17 years with no ocular abnormality except refractive error. After a comprehensive eye exam and axial length measurement, high definition macular scans were performed using SD-OCT. Two observers manually measured the choroidal thickness at the foveal center and at 1500 µm nasally, temporally, inferiorly, and superiorly. Interocular differences were computed; correlations with age, gender, refractive error, and axial length were performed. Results. Mean age was 10.40 ± 3.17 years; mean axial length and refractive error values were similar between fellow eyes. There was excellent correlation between the two observers’ measurements. No significant interocular differences were observed at any location. There was only a trend for right eyes to have higher values in all thicknesses, except the superior thickness. Most of the choroidal thickness measurements correlated positively with spherical equivalent but not with axial length, age, or gender. Conclusion. Choroidal thickness measurements in children as performed using SD-OCT revealed a high level of interobserver agreement and consistent interocular symmetry. Values correlated positively with spherical equivalent refraction.

Interocular symmetry in macular choroidal thickness in children.

Science.gov (United States)

Al-Haddad, Christiane; El Chaar, Lama; Antonios, Rafic; El-Dairi, Mays; Noureddin, Baha'

2014-01-01

Objective. To report interocular differences in choroidal thickness in children using spectral domain optical coherence tomography (SD-OCT) and correlate findings with biometric data. Methods. This observational cross-sectional study included 91 (182 eyes) healthy children aged 6 to 17 years with no ocular abnormality except refractive error. After a comprehensive eye exam and axial length measurement, high definition macular scans were performed using SD-OCT. Two observers manually measured the choroidal thickness at the foveal center and at 1500 µm nasally, temporally, inferiorly, and superiorly. Interocular differences were computed; correlations with age, gender, refractive error, and axial length were performed. Results. Mean age was 10.40 ± 3.17 years; mean axial length and refractive error values were similar between fellow eyes. There was excellent correlation between the two observers' measurements. No significant interocular differences were observed at any location. There was only a trend for right eyes to have higher values in all thicknesses, except the superior thickness. Most of the choroidal thickness measurements correlated positively with spherical equivalent but not with axial length, age, or gender. Conclusion. Choroidal thickness measurements in children as performed using SD-OCT revealed a high level of interobserver agreement and consistent interocular symmetry. Values correlated positively with spherical equivalent refraction.

Olivier Caïra, Jeux de rôle. Les forges de la fiction

Directory of Open Access Journals (Sweden)

Antoine Dauphragne

2010-06-01

Full Text Available Les forges de la fiction, d’Olivier Caïra, est à ranger parmi les rares ouvrages francophones en sciences humaines s’attachant au jeu de rôles. L’ouvrage en propose une analyse fine et dynamique centrée sur la pratique des joueurs. La démarche annoncée, qui entend proposer un texte accessible aussi bien aux rôlistes qu’aux universitaires, semble renvoyer autant à un souci de clarté qu’au profil de l’auteur. Olivier Caïra est sociologue ; ses travaux portent sur l’industrie du divertissement e...

Study on optimum length of raw material in stainless steel high-lock nuts forging

Science.gov (United States)

Cheng, Meiwen; Liu, Fenglei; Zhao, Qingyun; Wang, Lidong

2018-04-01

Taking 302 stainless steel (1Cr18Ni9) high-lock nuts for research objects, adjusting the length of raw material, then using DEFORM software to simulate the isothermal forging process of each station and conducting the corresponding field tests to study the effects of raw material size on the stainless steel high-lock nuts forming performance. The tests show that the samples of each raw material length is basically the same as the results of the DEFORM software. When the length of the raw material is 10mm, the appearance size of the parts can meet the design requirements.

Studies of the quality and cost-effectiveness of a novel conceptof open-die forged powerplant main shaft

Directory of Open Access Journals (Sweden)

P. Skubisz

2015-04-01

Full Text Available An innovatory concept of open-die forging of windmill main shaft is described. Comparative study of the new technology based on the concept of cogging hollow shaft on mandrel featuring material savings and higher quality of a finished part versus traditional production chain of this component is presented, indicating benefits and technological setbacks of industrial implementation. Results of industrial sampling aided with numerical simulation form guidelines for technological realization.

Versatile technique for assessing thickness of 2D layered materials by XPS

Science.gov (United States)

Zemlyanov, Dmitry Y.; Jespersen, Michael; Zakharov, Dmitry N.; Hu, Jianjun; Paul, Rajib; Kumar, Anurag; Pacley, Shanee; Glavin, Nicholas; Saenz, David; Smith, Kyle C.; Fisher, Timothy S.; Voevodin, Andrey A.

2018-03-01

X-ray photoelectron spectroscopy (XPS) has been utilized as a versatile method for thickness characterization of various two-dimensional (2D) films. Accurate thickness can be measured simultaneously while acquiring XPS data for chemical characterization of 2D films having thickness up to approximately 10 nm. For validating the developed technique, thicknesses of few-layer graphene (FLG), MoS2 and amorphous boron nitride (a-BN) layer, produced by microwave plasma chemical vapor deposition (MPCVD), plasma enhanced chemical vapor deposition (PECVD), and pulsed laser deposition (PLD) respectively, were accurately measured. The intensity ratio between photoemission peaks recorded for the films (C 1s, Mo 3d, B 1s) and the substrates (Cu 2p, Al 2p, Si 2p) is the primary input parameter for thickness calculation, in addition to the atomic densities of the substrate and the film, and the corresponding electron attenuation length (EAL). The XPS data was used with a proposed model for thickness calculations, which was verified by cross-sectional transmission electron microscope (TEM) measurement of thickness for all the films. The XPS method determines thickness values averaged over an analysis area which is orders of magnitude larger than the typical area in cross-sectional TEM imaging, hence provides an advanced approach for thickness measurement over large areas of 2D materials. The study confirms that the versatile XPS method allows rapid and reliable assessment of the 2D material thickness and this method can facilitate in tailoring growth conditions for producing very thin 2D materials effectively over a large area. Furthermore, the XPS measurement for a typical 2D material is non-destructive and does not require special sample preparation. Therefore, after XPS analysis, exactly the same sample can undergo further processing or utilization.

Influence of sulphur and phosphorus impurities on ductility of 25Kh2NMFA steel during forging

International Nuclear Information System (INIS)

Onishchenko, A.K.

1989-01-01

Using cylindrical samples of the 25Kh2NMFA steel with sulfur and phosphorus content in the range of 0.001-0.030%, tensile test with the rate of deformation 10 -3 s -1 at the temperatures of 800-1200 deg C has been conducted. Analysis of fracture foci and plasticity diagrams has shown, that to ensure ductility during forging and high mechanical properties, the content of sulfur and phosphorus impurities in the 25Kh2NMFA steel must not exceed 0.015%

Simulation and experimental verification of the filling process of semi-solid die forging for cup shell

OpenAIRE

Jianbo TAN; Zichao WANG; Dongxu WANG

2015-01-01

The filling mold process of semi-solid alloy blank influences severely the forming and properties of finished piece. In this paper, DEFORM is applied to simulate the process of cup-type 6061 alloy die forging casting. The influences of the temperature of semi-solid alloy blank, preheating temperature, and downward press speed of pressure head on process of mold filling and velocity field are investigated. The results show that the mold filling of semi-solid alloy paste smoothly fills along th...

Facial soft tissue thickness in North Indian adult population

Directory of Open Access Journals (Sweden)

Tanushri Saxena

2012-01-01

Full Text Available Objectives: Forensic facial reconstruction is an attempt to reproduce a likeness of facial features of an individual, based on characteristics of the skull, for the purpose of individual identification - The aim of this study was to determine the soft tissue thickness values of individuals of Bareilly population, Uttar Pradesh, India and to evaluate whether these values can help in forensic identification. Study design: A total of 40 individuals (19 males, 21 females were evaluated using spiral computed tomographic (CT scan with 2 mm slice thickness in axial sections and soft tissue thicknesses were measured at seven midfacial anthropological facial landmarks. Results: It was found that facial soft tissue thickness values decreased with age. Soft tissue thickness values were less in females than in males, except at ramus region. Comparing the left and right values in individuals it was found to be not significant. Conclusion: Soft tissue thickness values are an important factor in facial reconstruction and also help in forensic identification of an individual. CT scan gives a good representation of these values and hence is considered an important tool in facial reconstruction- This study has been conducted in North Indian population and further studies with larger sample size can surely add to the data regarding soft tissue thicknesses.

Quantifying Local Thickness and Composition in Thin Films of Organic Photovoltaic Blends by Raman Scattering

KAUST Repository

Rodríguez-Martínez, Xabier

2017-07-06

We report a methodology based on Raman spectroscopy that enables the non-invasive and fast quantitative determination of local thickness and composition in thin films (from few monolayers to hundreds of nm) of one or more components. We apply our methodology to blends of organic conjugated materials relevant in the field of organic photovoltaics. As a first step, we exploit the transfer-matrix formalism to describe the Raman process in thin films including reabsorption and interference effects of the incoming and scattered electric fields. This allows determining the effective solid-state Raman cross-section of each material by studying the dependence of the Raman intensity on film thickness. These effective cross sections are then used to estimate the local thickness and composition in a series of polymer:fullerene blends. We find that the model is accurate within ±10 nm in thickness and ±5 vol% in composition provided that (i) the film thickness is kept below the thickness corresponding to the first maximum of the calculated Raman intensity oscillation; (ii) the materials making up the blend show close enough effective Raman cross-sections; and (iii) the degree of order attained by the conjugated polymer in the blend is similar to that achieved when cast alone. Our methodology opens the possibility to make quantitative maps of composition and thickness over large areas (from microns to centimetres squared) with diffraction-limited resolution and in any multi-component system based thin film technology.

Regional Analysis of Soft Tissue Thickness on Korean Buttocks and Application to Fasciocutaneous Flap Design

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Do Yup Kim

2014-03-01

Full Text Available Background Various shapes and designs of the gluteal artery perforator flap have been used for treating sacral pressure sores and reconstructing breasts. To establish the ideal fasciocutaneous flap design for use in the gluteal area, the soft tissue thickness distribution was measured. Methods Twenty-one buttocks of adult Korean cadavers were analyzed through rectangular subfascial dissection. Each buttock was divided horizontally into 10 sections and vertically into 10 sections, and then, the thickness at the corners of the sections was measured. For the sake of comparison and statistical verification with living bodies, computed tomography (CT images of 120 buttocks of patients were randomly selected. Five horizontal sections and 4 vertical sections were made, and the thickness at each corner was recorded. Results According to the dissection and the CT images, the area with the thinnest soft tissues in the buttock was around the posterior superior iliac spine, close to the sacral area. The thickest area was the superolateral area of the buttock, which was 3.24 times and 2.15 times thicker than the thinnest area in the studies on cadaver anatomy and the CT images, respectively. Conclusions The thickness of the soft tissues in the buttocks differed by area. The superolateral area had the thickest soft tissues, and the superomedial area had the thinnest. This study includes information on the distribution of the thickness of the gluteal soft tissues of Koreans. The outcome of this study may contribute to the design of effective local flaps for pressure sore reconstruction and free flaps for breast reconstruction.

Process parameter influence on Electro-sinter-forging (ESF) of titanium discs

DEFF Research Database (Denmark)

Cannella, Emanuele; Nielsen, Chris Valentin; Bay, Niels

Electro-sinter-forging (ESF) is an innovative sintering process based on the principle of electrical Joule heating. The electrical current is flowing through the powder compact, which is under mechanical pressure. As compared to conventional sintering [1] and spark plasma sintering [2], the main...... advantages are the decreased sintering time and high relative density [3]. Near net-shape components can be manufactured and post-removal processing is limited to surface polishing. The present work is focused on analysing the influence of the main process parameters, namely compacting pressure, sintering...... time and electrical current density, on the final density of a disc sample made from commercially pure titanium powder. The maximum achieved relative density was 94% of the bulk density of pure titanium. The density estimation was carried out by using both Archimedes’ and 3D scanning....

Optimization of specimen preparation of thin cell section for AFM observation

Energy Technology Data Exchange (ETDEWEB)

Li Xinhui [Nanobiology Laboratory, Bio-X Life Science Research Center, School of Life Science and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240 (China); Ji Tong [Department of Oral and Maxillofacial Surgery, School of Stomatology, Affiliated Ninth People' s Hospital, Medical School, Shanghai Jiao Tong University, Shanghai 200011 (China); Hu Jun [Nanobiology Laboratory, Bio-X Life Science Research Center, School of Life Science and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240 (China); Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Sun Jielin [Nanobiology Laboratory, Bio-X Life Science Research Center, School of Life Science and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240 (China)], E-mail: jlsun@sjtu.edu.cn

2008-08-15

High resolution imaging of intracellular structures of ultrathin cell section samples is critical to the performance of precise manipulation by atomic force microscopy (AFM). Here, we test the effect of multiple factors during section sample preparation on the quality of the AFM image. These factors include the embedding materials, the annealing process of the specimen block, section thickness, and section side. We found that neither the embedding materials nor the temperature and speed of the annealing process has any effect on AFM image resolution. However, the section thickness and section side significantly affect the surface topography and AFM image resolution. By systematically testing the image quality of both sides of cell sections over a wide range of thickness (40-1000 nm), we found that the best resolution was obtained with upper-side sections approximately 50-100 nm thick. With these samples, we could observe precise structure details of the cell, including its membrane, nucleoli, and other organelles. Similar results were obtained for other cell types, including Tca8113, C6, and ECV-304. In brief, by optimizing the condition of ultrathin cell section preparation, we were able to obtain high resolution intracellular AFM images, which provide an essential basis for further AFM manipulation.

Morphometric measurement of submucosal thickness in areas of fat deposition in the terminal ileum and colonic sections, with correlation with body mass index, weight and age: a male autopsy study.

Science.gov (United States)

Mesa, Hector; Drawz, Sarah; Dykoski, Richard; Manivel, Juan Carlos

2015-10-01

An increased amount of submucosal (SM) fat in the colon on imaging is considered to be characteristic of inflammatory bowel disease (IBD); however, a recent study in patients without IBD reported a correlation between colonic SM fat deposition and body weight (BW). The aim of this study was to perform a morphometric investigation of SM thickness in areas of fat deposition in the terminal ileum (TI), ileocaecal valve (ICV), and colonic sections, to determine whether there are variations by site, and whether it shows a correlation with BW, body mass index (BMI), or age. Representative samples of TI, ICV and colonic sections were collected prospectively from 115 autopsy cases without IBD. All of the study subjects were male (Veterans Hospital). SM thickness was measured in areas of fat deposition. Correlation analysis was performed between SM thickness and BW, BMI, and age. Fat deposition was common; however, with the exception of the ICV, it was neither consistent nor prominent, and it did not show a statistical correlation with BW, BMI, or age. SM fat deposition is common but not uniform or conspicuous in the TI or colon. In contrast to extravisceral intra-abdominal fat, it does not show a correlation with BW or BMI, and is not associated with ageing. As all study subjects were male, gender-dependent variability cannot be excluded. © 2015 John Wiley & Sons Ltd.

The FORGE AHEAD clinical readiness consultation tool: a validated tool to assess clinical readiness for chronic disease care mobilization in Canada's First Nations.

Science.gov (United States)

Hayward, Mariam Naqshbandi; Mequanint, Selam; Paquette-Warren, Jann; Bailie, Ross; Chirila, Alexandra; Dyck, Roland; Green, Michael; Hanley, Anthony; Tompkins, Jordan; Harris, Stewart

2017-03-23

Given the astounding rates of diabetes and related complications, and the barriers to providing care present in Indigenous communities in Canada, intervention strategies that take into account contextual factors such as readiness to mobilize are needed to maximize improvements and increase the likelihood of success and sustainment. As part of the national FORGE AHEAD Program, we sought to develop, test and validate a clinical readiness consultation tool aimed at assessing the readiness of clinical teams working on-reserve in First Nations communities to participate in quality improvement (QI) to enhance diabetes care in Canada. A literature review was conducted to identify existing readiness tools. The ABCD - SAT was adapted using a consensus approach that emphasized a community-based participatory approach and prioritized the knowledge and wisdom held by community members. The tool was piloted with a group of 16 people from 7 provinces and 11 partnering communities to assess language use, clarity, relevance, format, and ease of completion using examples. Internal reliability analysis and convergence validity were conducted with data from 53 clinical team members from 11 First Nations communities (3-5 per community) who have participated in the FORGE AHEAD program. The 27-page Clinical Readiness Consultation Tool (CRCT) consists of five main components, 21 sub-components, and 74 items that are aligned with the Expanded Chronic Care Model. Five-point Likert scale feedback from the pilot ranged from 3.25 to 4.5. Length of the tool was reported as a drawback but respondents noted that all the items were needed to provide a comprehensive picture of the healthcare system. Results for internal consistency showed that all sub-components except for two were within acceptable ranges (0.77-0.93). The Team Structure and Function sub-component scale had a moderately significant positive correlation with the validated Team Climate Inventory, r = 0.45, p < 0.05. The

Evaluation of the x-ray fluorescence method of precious metal plating thickness measurements. Technological spinoff report

International Nuclear Information System (INIS)

Carson, J.S.; Hearn, N.K.; Pettie, C.B.

1975-09-01

It is shown that gold and silver plating thickness measurements made using an x-ray spectrograph could be closely correlated with thicknesses measured from sectional samples. Good correlations were also shown for single overlays of gold over silver when each layer was less than 0.0003 inch thick

Increased Cortical Thickness in Professional On-Line Gamers

Science.gov (United States)

Hyun, Gi Jung; Shin, Yong Wook; Kim, Bung-Nyun; Cheong, Jae Hoon; Jin, Seong Nam

2013-01-01

Objective The bulk of recent studies have tested whether video games change the brain in terms of activity and cortical volume. However, such studies are limited by several factors including cross-sectional comparisons, co-morbidity, and short-term follow-up periods. In the present study, we hypothesized that cognitive flexibility and the volume of brain cortex would be correlated with the career length of on-line pro-gamers. Methods High-resolution magnetic resonance scans were acquired in twenty-three pro-gamers recruited from StarCraft pro-game teams. We measured cortical thickness in each individual using FreeSurfer and the cortical thickness was correlated with the career length and the performance of the pro-gamers. Results Career length was positively correlated with cortical thickness in three brain regions: right superior frontal gyrus, right superior parietal gyrus, and right precentral gyrus. Additionally, increased cortical thickness in the prefrontal cortex was correlated with winning rates of the pro-game league. Increased cortical thickness in the prefrontal and parietal cortices was also associated with higher performance of Wisconsin Card Sorting Test. Conclusion Our results suggest that in individuals without pathologic conditions, regular, long-term playing of on-line games is associated with volume changes in the prefrontal and parietal cortices, which are associated with cognitive flexibility. PMID:24474988

Magnetic powder crack tests as a means of quality assurance in forged parts

International Nuclear Information System (INIS)

Deutsch, V.

1979-01-01

The magnetic powder process has been used for years for crack detection in forged parts, which are used as safety parts in car construction. The representation of the present state of technology appears useful, as terms and units have been redefined in DIN draft standards and guidelines, and because alternating field magnetisation has increasingly displaced earlier techniques. The correct choice of equipment, test materials and UV lamps, and the configuration of the working positions are discussed. As the complete automation of this test method is not possible at present, the organisation of the viewing process is of great importance. The comparison with other processes of non-destructive material testing proves the irreplaceability of the magnetic power crack testing at present. (orig.) [de

Smoking influences on the thickness of marginal gingival epithelium

Directory of Open Access Journals (Sweden)

Villar Cristina Cunha

2003-01-01

Full Text Available Smoking patients show reduction of inflammatory clinical signs that might be associated with local vasoconstriction and an increased gingival epithelial thickness. The purpose of this work was to evaluate the thickness of the marginal gingival oral epithelium in smokers and non-smokers, with clinically healthy gingivae or with gingivitis. Twenty biopsies were obtained from four different groups. Group I: non-smokers with clinically healthy gingivae (n = 5. Group II: non-smokers with gingivitis (n = 5. Group III: smokers with clinically healthy gingivae (n = 5. Group IV: smokers with gingivitis (n = 5. These biopsies were histologically processed, serially sectioned at 5 mm, stained with H. E., and examined by image analysis software (KS400, which was used to perform the morphometric evaluation and the quantification of the major epithelial thickness, the epithelial base thickness and the external and internal epithelial perimeters. Differences between the four groups were analyzed using ANOVA test and Tukey's test. The criteria for statistical significance were accepted at the probability level p < 0.05. A greater epithelial thickness was observed in smokers independent of the gingival health situation.

Sediment Thickness and a WEST-EAST Geologic Cross Section in the Caracas Valley

OpenAIRE

KANTAK, PETER; SCHMITZ, MICHAEL; AUDEMARD, FRANCK

2005-01-01

Caracas is located at the Caribbean - South America plate boundary zone, with an associated strike slip fault system, which accommodates the relative movement of both plates and is responsible for the seismic hazard in the region. The damage pattern of the 1967 Caracas earthquake emphasized the existence of important site effects due to the sedimentary basin fill of the Caracas valley. A revised map of the sedimentary thickness was developed during this study, based on drill holes (mostly fro...

Hexaferrite multiferroics: from bulk to thick films

Science.gov (United States)

Koutzarova, T.; Ghelev, Ch; Peneva, P.; Georgieva, B.; Kolev, S.; Vertruyen, B.; Closset, R.

2018-03-01

We report studies of the structural and microstructural properties of Sr3Co2Fe24O41 in bulk form and as thick films. The precursor powders for the bulk form were prepared following the sol-gel auto-combustion method. The prepared pellets were synthesized at 1200 °C to produce Sr3Co2Fe24O41. The XRD spectra of the bulks showed the characteristic peaks corresponding to the Z-type hexaferrite structure as a main phase and second phases of CoFe2O4 and Sr3Fe2O7-x. The microstructure analysis of the cross-section of the bulk pellets revealed a hexagonal sheet structure. Large areas were observed of packages of hexagonal sheets where the separate hexagonal particles were ordered along the c axis. Sr3Co2Fe24O41 thick films were deposited from a suspension containing the Sr3Co2Fe24O41 powder. The microstructural analysis of the thick films showed that the particles had the perfect hexagonal shape typical for hexaferrites.

Determination of accurate metal silicide layer thickness by RBS

International Nuclear Information System (INIS)

Kirchhoff, J.F.; Baumann, S.M.; Evans, C.; Ward, I.; Coveney, P.

1995-01-01

Rutherford Backscattering Spectrometry (RBS) is a proven useful analytical tool for determining compositional information of a wide variety of materials. One of the most widely utilized applications of RBS is the study of the composition of metal silicides (MSi x ), also referred to as polycides. A key quantity obtained from an analysis of a metal silicide is the ratio of silicon to metal (Si/M). Although compositional information is very reliable in these applications, determination of metal silicide layer thickness by RBS techniques can differ from true layer thicknesses by more than 40%. The cause of these differences lies in how the densities utilized in the RBS analysis are calculated. The standard RBS analysis software packages calculate layer densities by assuming each element's bulk densities weighted by the fractional atomic presence. This calculation causes large thickness discrepancies in metal silicide thicknesses because most films form into crystal structures with distinct densities. Assuming a constant layer density for a full spectrum of Si/M values for metal silicide samples improves layer thickness determination but ignores the underlying physics of the films. We will present results of RBS determination of the thickness various metal silicide films with a range of Si/M values using a physically accurate model for the calculation of layer densities. The thicknesses are compared to scanning electron microscopy (SEM) cross-section micrographs. We have also developed supporting software that incorporates these calculations into routine analyses. (orig.)

Analysis of residual stress in subsurface layers after precision hard machining of forging tools

Directory of Open Access Journals (Sweden)

Czan Andrej

2018-01-01

Full Text Available This paper is focused on analysis of residual stress of functional surfaces and subsurface layers created by precision technologies of hard machining for progressive constructional materials of forging tools. Methods of experiments are oriented on monitoring of residual stress in surface which is created by hard turning (roughing and finishing operations. Subsequently these surfaces were etched in thin layers by electro-chemical polishing. The residual stress was monitored in each etched layer. The measuring was executed by portable X-ray diffractometer for detection of residual stress and structural phases. The results significantly indicate rise and distribution of residual stress in surface and subsurface layers and their impact on functional properties of surface integrity.

Cold forging stem of total hip prosthesis with hybrid mechanical properties

International Nuclear Information System (INIS)

Lopes, E.S.N.; Contieri, R.J.; Cardoso, F.F.; Cremasco, A.; Button, S.T.; Caram, R.

2010-01-01

Type β Ti alloy is one of the most versatile groups of materials with regard to mechanical properties. Aspects such as alloying elements selection, mechanical processing and heat treatment routes empower these materials in applications where hybrid mechanical behavior is necessary. The aim of this study is to produce stems of total hip prostheses with hybrid mechanical properties using Ti-Nb alloys. Ingots were produced by using arc melting. Following, samples were subjected to specific heat treatment aiming to make cold forging. Sample characterization includes X-ray diffraction, scanning electron microscopy, Vickers hardness tests and tensile test. The experiments performed allowed to examine the effects of heat treatment parameters on the microstructure and mechanical behavior. Finally, results obtained show that the application of specific heat treatments of quenching and aging makes feasible the manufacturing of orthopedic devices with hybrid mechanical properties with regions where high mechanical strength was prioritized, while in others, low elastic modulus was the main concern. (author)

Research on the Cross Section Precision of High-strength Steel Tube with Rectangular Section in Rotary Draw Bending

Science.gov (United States)

Yang, Hongliang; Zhao, Hao; Xing, Zhongwen

2017-11-01

For the demand of energy conservation and security improvement, high-strength steel (HSS) is increasingly being used to produce safety related automotive components. However, cross-section distortion occurs easily in bending of HSS tube with rectangular section (RS), affecting the forming precision. HSS BR1500HS tube by rotary draw bending is taken as the study object and a description method of cross-section distortion is proposed in this paper. The influence on cross-section precision of geometric parameters including cross-section position, thickness of tube, bend radius etc. are studied by experiment. Besides, simulation of the rotary draw bending of HSS tube with rectangular section by ABAQUS are carried out and compared to the experiment. The results by simulation agree well with the experiment and show that the cross-section is approximately trapezoidal after distortion; the maximum of distortion exists at 45 ∼ 60° of the bending direction; and the absolute and relative distortion values increase with the decreasing of tube thickness or bending radius. Therefore, the results can provide a reference for the design of geometric parameters of HSS tube with rectangular section in rotary draw bending.

Forging the frontiers: Travellers and documents on the South Africa-Mozambique border, 1890s-1940s

Directory of Open Access Journals (Sweden)

Andrew MacDonald

Full Text Available It is well known that the Union of South Africa started to build an onerous border regime at the turn of the twentieth century in order to secure a White Man's Country in southern Africa. Newly formed, ambitious Immigration Departments consequently targeted 'Asiatics', poor whites and finally 'surplus' Africans from the 1920s onwards. An infrastructure of exclusion (detention and deportation compounds, police patrols, fingerprint offices and so on soon emerged at the region's maritime gateways as the colonial states sought to undermine decentralised indigenous societies characterised by long-term mobility. This article shows that the Union remained vulnerable on its eastern frontier with Mozambique and Swaziland, where 'undesirables' continued to arrive in numbers. Long-distance movement had a long precedent in these borderlands, and it proved difficult for colonial states to forge effective border controls until deep into the twentieth century. Based on extensive and critical engagement with multiple border control archives, the article traces the gradual 'paperisation of the border, and follows a thriving market in identity permits in southern Mozambique and Swaziland, which became important backdoor entry points to the Union. The main people to exploit corrupt local officials and entrepreneurial headmen on either side of the border were those associated with the merchant houses of coastal west India, syndicates from the Portuguese Atlantic island of Madeira, and long-distance, so-called 'tropical', African migrants. Together they forged sophisticated networks that moved permits, people and money across the region and gave south-east Africa's border builders hard and often thankless paperwork.

Energy-efficiency in inductive heating of forging ingots; Energieeffizienz bei der induktiven Erwaermung von Schmiedebloecken

Energy Technology Data Exchange (ETDEWEB)

Padberg, Michael; Doetsch, Erwin [ABP Induction Systems, Dortmund (Germany)

2012-03-15

The continuously increasing importance of the CO{sub 2} balance and of conservation of resources is resulting in ever greater demands for high energy-efficiency in the process used for heating of forging ingots. Plant and process engineering play roles of parallel significance in the fulfillment of these requirements, and this article focuses on both in equal degree. The shares of the individual components in the overall energy consumption of an induction heating installation are therefore firstly determined, and their respective potentials for optimization then discussed. The quality of the heating process itself, and its optimum design for reduction of energy consumption, are then examined. (orig.)

Lead Thickness Measurements

International Nuclear Information System (INIS)

Rucinski, R.

1998-01-01

The preshower lead thickness applied to the outside of D-Zero's superconducting solenoid vacuum shell was measured at the time of application. This engineering documents those thickness measurements. The lead was ordered in sheets 0.09375-inch and 0.0625-inch thick. The tolerance on thickness was specified to be +/- 0.003-inch. The sheets all were within that thickness tolerance. The nomenclature for each sheet was designated 1T, 1B, 2T, 2B where the numeral designates it's location in the wrap and 'T' or 'B' is short for 'top' or 'bottom' half of the solenoid. Micrometer measurements were taken at six locations around the perimeter of each sheet. The width,length, and weight of each piece was then measured. Using an assumed pure lead density of 0.40974 lb/in 3 , an average sheet thickness was calculated and compared to the perimeter thickness measurements. In every case, the calculated average thickness was a few mils thinner than the perimeter measurements. The ratio was constant, 0.98. This discrepancy is likely due to the assumed pure lead density. It is not felt that the perimeter is thicker than the center regions. The data suggests that the physical thickness of the sheets is uniform to +/- 0.0015-inch.

Influence of quenching cooling rate on residual stress and tensile properties of 2A14 aluminum alloy forgings

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yu-xun, E-mail: zhangyuxun198@163.com; Yi, You-ping, E-mail: yyp@csu.edu.cn; Huang, Shi-quan, E-mail: huangsqcsu@sina.com; Dong, Fei

2016-09-30

To balance the quenching residual stress and the mechanical properties of aluminum alloys, the influence of cooling rate on the residual stress and tensile properties was investigated by numerical simulation and quenching experiments. During the quenching experiments, 2A14 aluminum alloy samples were treated with different water temperatures (20 °C, 70 °C, 100 °C) and a step quenching process. X-ray diffraction (XRD) was used to measure the residual stress. Prior to them, the quenching sensitivity was studied. For this purpose, the time-temperature-properties (TTP) curves were measured and the alloy microstructure was observed using transmission electron microscopy (TEM). The results indicated that the mechanical properties of 2A14 aluminum alloys were mainly determined by the cooling rate within the quenching sensitive temperature range from 300 to 400 °C. Lower cooling rates reduced the tensile strength and yield strength due to a decrease amount of fine precipitates, and reduced the residual stress with the reduction of plastic strain and the degree of inhomogeneous plastic deformation. In addition, the residual stress changed faster than the tensile properties with decreasing cooling rate. Therefore, warm water (70 °C) was used to balance the residual stress and tensile properties of 140-mm-thick 2A14 aluminum alloy forgings, since it can achieve low cooling rates. Furthermore, by combining this characteristic and the material quenching sensitivity, step quenching produced similar tensile properties and lower residual stress, compared with the sample quenched in warm water (70 °C), by increasing cooling rate within quenching sensitivity range and reducing it in other ranges.

Influence of quenching cooling rate on residual stress and tensile properties of 2A14 aluminum alloy forgings

International Nuclear Information System (INIS)

Zhang, Yu-xun; Yi, You-ping; Huang, Shi-quan; Dong, Fei

2016-01-01

To balance the quenching residual stress and the mechanical properties of aluminum alloys, the influence of cooling rate on the residual stress and tensile properties was investigated by numerical simulation and quenching experiments. During the quenching experiments, 2A14 aluminum alloy samples were treated with different water temperatures (20 °C, 70 °C, 100 °C) and a step quenching process. X-ray diffraction (XRD) was used to measure the residual stress. Prior to them, the quenching sensitivity was studied. For this purpose, the time-temperature-properties (TTP) curves were measured and the alloy microstructure was observed using transmission electron microscopy (TEM). The results indicated that the mechanical properties of 2A14 aluminum alloys were mainly determined by the cooling rate within the quenching sensitive temperature range from 300 to 400 °C. Lower cooling rates reduced the tensile strength and yield strength due to a decrease amount of fine precipitates, and reduced the residual stress with the reduction of plastic strain and the degree of inhomogeneous plastic deformation. In addition, the residual stress changed faster than the tensile properties with decreasing cooling rate. Therefore, warm water (70 °C) was used to balance the residual stress and tensile properties of 140-mm-thick 2A14 aluminum alloy forgings, since it can achieve low cooling rates. Furthermore, by combining this characteristic and the material quenching sensitivity, step quenching produced similar tensile properties and lower residual stress, compared with the sample quenched in warm water (70 °C), by increasing cooling rate within quenching sensitivity range and reducing it in other ranges.

Overweight is not associated with cortical thickness alterations in children

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Rachel Jane Sharkey

2015-02-01

Full Text Available IntroductionSeveral studies report an association between body mass index (BMI and cortical thickness in adults. Some studies demonstrate diffuse cortical thinning in obesity, while others report effects in areas that are associated with self-regulation, such as lateral prefrontal cortex. MethodsThis study used multilevel modelling of data from the NIH Pediatric MRI Data Repository, a mixed longitudinal and cross-sectional database, to examine the relationship between cortical thickness and body weight in children. Cortical thickness was computed at 81,942 vertices of 716 MRI scans from 378 children aged between 4 and 18 years. Body mass index Z score for age was computed for each participant. We preformed vertex-wise statistical analysis of the relationship between cortical thickness and BMI, accounting for age and gender. In addition, cortical thickness was extracted from regions of interest in prefrontal cortex and insula.ResultsNo significant association between cortical thickness and BMI was found, either by statistical parametric mapping or by region of interest analysis. Results remained negative when the analysis was restricted to children aged 12-18.ConclusionsThe correlation between BMI and cortical thickness was not found in this large pediatric sample. The association between BMI and cortical thinning develops after adolescence. This has implications for the nature of the relationship between brain anatomy and weight gain.

A brief history of Forging New Frontiers, the annual conference of the Injury Free Coalition for Kids.

Science.gov (United States)

Johnson, Estell Lenita; Barlow, Barbara

2016-10-01

The Injury Free Coalition for Kids Annual Conference has contributed to the dissemination of information pertaining to the development of the field of injury prevention. A content analysis was completed using conference agendas used during the span of 2005-2015, finding that more than 398 presentations covering a wide variety of injuries have taken place. Published work has appeared in the Journal of Trauma and there has been recognition of people who have contributed to the development of the field. Forging New Frontiers is a valuable tool for attendees to exchange information about injury prevention.

Turbine airfoil having outboard and inboard sections

Science.gov (United States)

Mazzola, Stefan; Marra, John J

2015-03-17

A turbine airfoil usable in a turbine engine and formed from at least an outboard section and an inboard section such that an inner end of the outboard section is attached to an outer end of the inboard section. The outboard section may be configured to provide a tip having adequate thickness and may extend radially inward from the tip with a generally constant cross-sectional area. The inboard section may be configured with a tapered cross-sectional area to support the outboard section.

Thickness of the Buccal Plate in Posterior Teeth: A Prospective Cone Beam Computed Tomography Study.

Science.gov (United States)

Temple, Kayleigh Eaves; Schoolfield, John; Noujeim, Marcel E; Huynh-Ba, Guy; Lasho, David J; Mealey, Brian L

Buccal plate thickness is an important clinical parameter for postextraction implant treatment planning. The purpose of this study was to assess buccal plate thickness of the posterior maxilla and mandible using cone beam computed tomography (CBCT). A total of 265 patients and 934 teeth met the inclusion criteria for this study. CBCT volumes were taken and aligned for measurement at the ideal midsagittal cross-section. Buccal plate thickness was measured at 1, 3, and 5 mm apical to the alveolar crest. The frequency of thick (≥ 1 mm), thin (teeth.

Estimation of soft- and hard-tissue thickness at implant sites

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Anil Kumar

2014-01-01

Full Text Available Introduction: Anchorage control is a critical consideration when planning treatment for patients with dental and skeletal malocclusions. To obtain sufficient stability of implants, the thickness of the soft tissue and the cortical-bone in the placement site must be considered; so as to provide an anatomical map in order to assist the clinician in the placement of the implants. Objective: The aim of this study is to evaluate the thickness of soft- and hard-tissue. Materials and Methods: To measure soft tissue and cortical-bone thicknesses, 12 maxillary cross-sectional specimens were obtained from the cadavers, which were made at three maxillary mid-palatal suture areas: The interdental area between the first and second premolars (Group 1, the second premolar and the first molar (Group 2, and the first and second molars (Group 3. Sectioned samples along with reference rulers were digitally scanned. Scanned images were calibrated and measurements were made with image-analysis software. We measured the thickness of soft and hard-tissues at five sectional areas parallel to the buccopalatal cementoenamel junction (CEJ line at 2-mm intervals and also thickness of soft tissue at the six landmarks including the incisive papilla (IP on the palate. The line perpendicular to the occlusal plane was made and measurement was taken at 4-mm intervals from the closest five points to IP. Results: (1 Group 1:6 mm from CEJ in buccal side and 2 mm from CEJ in palatal side. (2 Group 2:8 mm from CEJ in buccal side and 4 mm from CEJ in palatal side. (3 Group 3:8 mm from CEJ in buccal side and 8 mm from CEJ in palatal side. Conclusions: The best site for placement of implant is with thinnest soft tissue and thickest hard tissue, which is in the middle from CEJ in buccal side and closest from CEJ in palatal side in Group 1 and faraway from CEJ in buccal side and closest from CEJ in palatal side in Group 2 and faraway from CEJ in buccal side and faraway from CEJ in palatal

Use of apparent thickness for preprocessing of low-frequency electromagnetic data in inversion-based multibarrier evaluation workflow

Science.gov (United States)

Omar, Saad; Omeragic, Dzevat

2018-04-01

The concept of apparent thicknesses is introduced for the inversion-based, multicasing evaluation interpretation workflow using multifrequency and multispacing electromagnetic measurements. A thickness value is assigned to each measurement, enabling the development of two new preprocessing algorithms to remove casing collar artifacts. First, long-spacing apparent thicknesses are used to remove, from the pipe sections, artifacts ("ghosts") caused by the transmitter crossing a casing collar or corrosion. Second, a collar identification, localization, and assignment algorithm is developed to enable robust inversion in collar sections. Last, casing eccentering can also be identified on the basis of opposite deviation of short-spacing phase and magnitude apparent thicknesses from the nominal value. The proposed workflow can handle an arbitrary number of nested casings and has been validated on synthetic and field data.

Anatomical characterization of central, apical and minimal corneal thickness

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Federico Saenz-Frances

2014-08-01

Full Text Available AIM: To anatomically locate the points of minimum corneal thickness and central corneal thickness (pupil center in relation to the corneal apex.METHODS: Observational, cross-sectional study, 299 healthy volunteers. Thickness at the corneal apex (AT, minimum corneal thickness (MT and corneal thickness at the pupil center (PT were determined using the pentacam. Distances from the corneal apex to MT (MD and PT (PD were calculated and their quadrant position (taking the corneal apex as the reference determined:point of minimum thickness (MC and point of central thickness (PC depending on the quadrant position. Two multivariate linear regression models were constructed to examine the influence of age, gender, power of the flattest and steepest corneal axes, position of the flattest axis, corneal volume (determined using the Pentacam and PT on MD and PD. The effects of these variables on MC and PC were also determined in two multinomial regression models.RESULTS: MT was located at a mean distance of 0.909 mm from the apex (79.4% in the inferior-temporal quadrant. PT was located at a mean distance of 0.156 mm from the apex. The linear regression model for MD indicated it was significantly influenced by corneal volume (B=-0.024; 95%CI:-0.043 to -0.004. No significant relations were identified in the linear regression model for PD or the multinomial logistic regressions for MC and PC.CONCLUSION: MT was typically located at the inferior-temporal quadrant of the cornea and its distance to the corneal apex tended to decrease with the increment of corneal volume.

Effect of a Finite Trailing Edge Thickness on the Drag of Rectangular and Delta Wings at Supersonic Speeds

National Research Council Canada - National Science Library

Klunker, E

1952-01-01

The effect of a finite trailing-edge thickness on the pressure drag of rectangular and delta wings with truncated diamond-shaped airfoil sections with a given thickness ratio is studied for supersonic...

Extended methods using thick-targets for nuclear reaction data of radioactive isotopes

Science.gov (United States)

Ebata, Shuichiro; Aikawa, Masayuki; Imai, Shotaro

2017-09-01

The nuclear transmutation is a technology to dispose of radioactive wastes. However, we do not have enough basic data for its developments, such as thick-target yields (TTY) and the interaction cross sections for radioactive material. We suggest two methods to estimate the TTY using inverse kinematics and to obtain the excitation function of the interaction cross sections which is named the thick-target transmission (T3) method. We deduce the energy-dependent conversion relation between the TTYs of the original system and its inverse kinematics, which can be replaced to a constant coefficient in the high energy region. Furthermore we show the usefulness of the T3 method to investigate the excitation function of the 12C + 27Al reaction in the simulation.

Thickness determination of large-area films of yttria-stabilized zirconia produced by pulsed laser deposition

DEFF Research Database (Denmark)

Pryds, N.; Christensen, Bo Toftmann; Bilde-Sørensen, Jørgen

2006-01-01

of the attenuation for various values of film thickness with the program CASINO. These results have been compared with direct measurements in the SEM of the film thickness on a cross-section on one of the wafers. The results of these measurements demonstrate the ability of this technique to accurately determine...

Mediterranean diet, micronutrients and macronutrients, and MRI measures of cortical thickness.

Science.gov (United States)

Staubo, Sara C; Aakre, Jeremiah A; Vemuri, Prashanthi; Syrjanen, Jeremy A; Mielke, Michelle M; Geda, Yonas E; Kremers, Walter K; Machulda, Mary M; Knopman, David S; Petersen, Ronald C; Jack, Clifford R; Roberts, Rosebud O

2017-02-01

The Mediterranean diet (MeDi) is associated with reduced risk of cognitive impairment, but it is unclear whether it is associated with better brain imaging biomarkers. Among 672 cognitively normal participants (mean age, 79.8 years, 52.5% men), we investigated associations of MeDi score and MeDi components with magnetic resonance imaging measures of cortical thickness for the four lobes separately and averaged (average lobar). Higher MeDi score was associated with larger frontal, parietal, occipital, and average lobar cortical thickness. Higher legume and fish intakes were associated with larger cortical thickness: legumes with larger superior parietal, inferior parietal, precuneus, parietal, occipital, lingual, and fish with larger precuneus, superior parietal, posterior cingulate, parietal, and inferior parietal. Higher carbohydrate and sugar intakes were associated with lower entorhinal cortical thickness. In this sample of elderly persons, higher adherence to MeDi was associated with larger cortical thickness. These cross-sectional findings require validation in prospective studies. Copyright © 2016 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

Generation and development of damage in double forged tungsten in different combined regimes of irradiation with extreme heat loads

Science.gov (United States)

Paju, Jana; Väli, Berit; Laas, Tõnu; Shirokova, Veroonika; Laas, Katrin; Paduch, Marian; Gribkov, Vladimir A.; Demina, Elena V.; Prusakova, Marina D.; Pimenov, Valeri N.; Makhlaj, Vadym A.; Antonov, Maksim

2017-11-01

Armour materials in fusion devices, especially in the region of divertor, are exposed to a continuous heat and particle load. In addition, several off-normal events can reach the material during a work session. Calculations show that the effects of plasma and heat during such events can lead to cracking, erosion and detachment of the armour material. On the other hand, mutual and combined influences of different kinds of heat and particle loads can lead to the amplification of defects or vice versa, to the mitigation of damages. Therefore, the purpose of the study is to investigate the plasma induced damages on samples of double forged tungsten, which is considered a potential candidate for armour material of future tokamak's divertor. The combined effect of different kinds of plasma induced damages was investigated and analysed in this research. The study was conducted by irradiating the samples in various irradiation regimes twice, to observe the accumulation of the damages. Afterwards the analysis of micro-topography, scanning electron microscopy images and electrical conductivity measurements was used. Results indicate that double-forging improved the tungsten's durability to irradiation. Nevertheless, powerful pulses lead to significant damage of the sample, which will lead to further deterioration in the bulk. Although the average micro-roughness on the sample's surface does not change, the overall height/depth ratios can change.

Detection of fission fragments using thick samples in contact with solid state nuclear track detectors

International Nuclear Information System (INIS)

Lima, D.A. de; Martins, J.B.; Tavares, O.A.P.

1987-01-01

Whenever use is made of thick samples in contact with solid state nuclear track detectors for determining fission yields, one of the fundamental problems is the evaluation of the effective number of target nuclei which contributes to the fraction of the number of fission events that will be recorded. The evaluation of the effective number of target nuclei which contributes to recorded events is based on the effective thickness of the sample. A method for evaluating effective thickness of thick samples for binary fission modes, is presented. A cross section equation which takes into account all the necessary corrections due to fragment attenuation effects by a thick target for calculation induced fission yields, was obtained. (Author) [pt

Effect of forging on mechanical properties of rice husk ash-silicon carbide reinforced Al1100 hybrid composites

Science.gov (United States)

Ghanaraja, S.; Gireesha, B. L.; Ravikumar, K. S.; Likith, P.

2018-04-01

During the past few years, material design has changed prominence to pursue light weight, environment friendliness, low cost, quality, higher service temperature, higher elastic modulus, improved wear resistance and performance. Straight monolithic materials have limitations in achieving the above decisive factors. To overcome these limitations and to convince the ever increasing demand of modern day technology, Attention has been shifted towards Metal Matrix Composites (MMC). Stir casting route is most hopeful for synthesizing discontinuous reinforcement aluminium matrix composites because of its relative simplicity and easy adaptability with all shape casting process used in metal casting industry. Hybridization of metal matrix composites is the introduction of more than one type/kind, size and shape of reinforcement during processing of composites. It is carried out to obtain synergistic properties of different reinforcements and matrix used, which may not be rea1ised in monolithic alloy or in conventional monocomposites. The present study involves synthesis of hybrid composites by addition of the desired amount of Silicon Carbide (SiC) and Rice Husk Ash (RHA) particles in to the molten Al 1100-Mg alloy through stir casting technique fallowed by hot forging of the cast composites. The influence of increasing in the wt% (3, 6, 9, 12 and 15 wt%) of SiC particles addition (3 wt% Rice husk ash kept constant) on evolution of microstructure is studied through XRD and SEM and their impact on the mechanical properties like hardness and tensile strength of the resulting forged hybrid composites has been investigated.

Movement Synchrony Forges Social Bonds Across Group Divides

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Bahar eTuncgenc

2016-05-01

Full Text Available Group dynamics play an important role in the social interactions of both children and adults. A large amount of research has shown that merely being allocated to arbitrarily defined groups can evoke disproportionately positive attitudes toward one’s in-group and negative attitudes toward out-groups, and that these biases emerge in early childhood. This prompts important empirical questions with far-reaching theoretical and applied significance. How robust are these inter-group biases? Can biases be mitigated by behaviors known to bond individuals and groups together? How can bonds be forged across existing group divides? To explore these questions, we examined the bonding effects of interpersonal synchrony on minimally constructed groups in a controlled experiment. In-group and out-group bonding were assessed using questionnaires administered before and after a task in which groups performed movements either synchronously or non-synchronously in a between-participants design. We also developed an implicit behavioral measure, the Island Game, in which physical proximity was used as an indirect measure of interpersonal closeness. Self-report and behavioral measures showed increased bonding between groups after synchronous movement. Bonding with the out-group was significantly higher in the condition in which movements were performed synchronously than when movements were performed non-synchronously between groups. The findings are discussed in terms of their importance for the developmental social psychology of group dynamics as well as their implications for applied intervention programs.

Research on Oxidation Wear Behavior of a New Hot Forging Die Steel

Science.gov (United States)

Shi, Yuanji; Wu, Xiaochun

2018-01-01

Dry sliding tests for the hot forging die steel DM were performed in air under the test temperature at 400-700 °C and the time of 0.5-4 h by a UMT-3 high-temperature wear tester. The wear behavior and characteristics were studied systematically to explore the general characters in severe oxidation conditions. The results showed that a mild-to-severe oxidation wear transition occurred with an increase in the test temperature and duration. The reason was clarified as the unstable M6C carbides coarsening should be responsible for the severe delamination of tribo-oxide layer. More importantly, an intense oxidation wear with lower wear rates was found when the experimental temperature reaches 700 °C or after 4 h of test time at 600 °C, which was closely related to the degradation behavior during wear test. Furthermore, a new schematic diagram of oxidation wear of DM steel was proposed.

THE ROLE OF THE COMPETITION POLICY IN FORGING THE EUROPEAN COMMON MARKET

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Radu-Cristian Muşetescu

2008-12-01

Full Text Available The forging of the Single Market represents the most important dimension of the first pillar of the European Union, which is the European Community. It can be argued that, as compared to the other two pillars (the Common Foreign and Security Policy and the Police and Judicial Cooperation in the Criminal Matters, it has the most powerful impact on the welfare of European citizens. The European policy makers define however the Internal Market as not only an economic area where there are no more state-imposed barriers in the path of the freedom of movement of goods and services at the borders of the member-states but also a single business environment where there are a single currency, coordinated economic policies as well as homogeneous business practices of private undertakings. In this process, despite a large set of common policies, the competition policy has reached the status of the building block of the Common Market.

Weldability Characteristics of Sintered Hot-Forged AISI 4135 Steel Produced through P/M Route by Using Pulsed Current Gas Tungsten Arc Welding

Science.gov (United States)

Joseph, Joby; Muthukumaran, S.; Pandey, K. S.

2016-01-01

Present investigation is an attempt to study the weldability characteristics of sintered hot-forged plates of AISI 4135 steel produced through powder metallurgy (P/M) route using matching filler materials of ER80S B2. Compacts of homogeneously blended elemental powders corresponding to the above steel were prepared on a universal testing machine (UTM) by taking pre-weighed powder blend with a suitable die, punch and bottom insert assembly. Indigenously developed ceramic coating was applied on the entire surface of the compacts in order to protect them from oxidation during sintering. Sintered preforms were hot forged to flat, approximately rectangular plates, welded by pulsed current gas tungsten arc welding (PCGTAW) processes with aforementioned filler materials. Microstructural, tensile and hardness evaluations revealed that PCGTAW process with low heat input could produce weldments of good quality with almost nil defects. It was established that PCGTAW joints possess improved tensile properties compared to the base metal and it was mainly attributed to lower heat input, resulting in finer fusion zone grains and higher fusion zone hardness. Thus, the present investigation opens a new and demanding field in research.

Macular thickness and macular volume measurements using spectral domain optical coherence tomography in normal Nepalese eyes

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Pokharel A

2016-03-01

Full Text Available Amrit Pokharel,1 Gauri Shankar Shrestha,2 Jyoti Baba Shrestha2 1Department of Ophthalmology, Kathmandu Medical College Teaching Hospital, 2B P Koirala Lions Centre for Ophthalmic Studies, Institute of Medicine, Kathmandu, Nepal Purpose: To record the normative values for macular thickness and macular volume in normal Nepalese eyes. Methods: In all, 126 eyes of 63 emmetropic subjects (mean age: 21.17±6.76 years; range: 10–37 years were assessed for macular thickness and macular volume, using spectral domain-optical coherence tomography over 6×6 mm2 in the posterior pole. A fast macular thickness protocol was employed. Statistics such as the mean, median, standard deviation, percentiles, and range were used, while a P-value was set at 0.05 to test significance. Results: Average macular thickness and total macular volume were larger in males compared to females. With each year of increasing age, these variables decreased by 0.556 µm and 0.0156 mm3 for average macular thickness and total macular volume, respectively. The macular thickness was greatest in the inner superior section and lowest at the center of the fovea. The volume was greatest in the outer nasal section and thinnest in the fovea. The central subfield thickness (r=-0.243, P=0.055 and foveal volume (r=0.216, P=0.09 did not correlate with age. Conclusion: Males and females differ significantly with regard to macular thickness and macular volume measurements. Reports by other studies that the increase in axial length reduced thickness and volume, were negated by this study which found a positive correlation among axial length, thickness, and volume. Keywords: macular thickness, macular volume, optical coherence tomography, Nepal

Effect of boundary layer thickness on the flow characteristics around a rectangular prism

International Nuclear Information System (INIS)

Ji, Ho Seong; Kim, Kyung Chun

2001-01-01

Effect of boundary layer thickness on the flow characteristics around a rectangular prism has been investigated by using a PIV(Particle Image Velocimetry) technique. Three different boundary layers (thick, medium and thin) were generated in the atmospheric boundary layer wind tunnel at Pusan National University. The thick boundary layer having 670mm thickness was generated by using spires and roughness elements. The medium thickness of boundary layer(δ=270mm) was the natural turbulent boundary layer at the test section with fully long developing length(18m). The thin boundary layer with 36.5mm thickness was generated by on a smooth panel elevated 70cm from the wind tunnel floor. The Reynolds number based on the free stream velocity and the height of the model was 7.9X10 3 . The mean velocity vector fields and turbulent kinetic energy distribution were measured and compared. The effect of boundary layer thickness is clearly observed not only in the length of separation bubble but also in the reattachment points. The thinner boundary layer thickness, the higher turbulent kinetic energy peak around the model roof. It is strongly recommended that the height ratio between model and approaching boundary layer thickness should be a major parameter

Does cortical bone thickness in the last sacral vertebra differ among tail types in primates?

Science.gov (United States)

Nishimura, Abigail C; Russo, Gabrielle A

2017-04-01

The external morphology of the sacrum is demonstrably informative regarding tail type (i.e., tail presence/absence, length, and prehensility) in living and extinct primates. However, little research has focused on the relationship between tail type and internal sacral morphology, a potentially important source of functional information when fossil sacra are incomplete. Here, we determine if cortical bone cross-sectional thickness of the last sacral vertebral body differs among tail types in extant primates and can be used to reconstruct tail types in extinct primates. Cortical bone cross-sectional thickness in the last sacral vertebral body was measured from high-resolution CT scans belonging to 20 extant primate species (N = 72) assigned to tail type categories ("tailless," "nonprehensile short-tailed," "nonprehensile long-tailed," and "prehensile-tailed"). The extant dataset was then used to reconstruct the tail types for four extinct primate species. Tailless primates had significantly thinner cortical bone than tail-bearing primates. Nonprehensile short-tailed primates had significantly thinner cortical bone than nonprehensile long-tailed primates. Cortical bone cross-sectional thickness did not distinguish between prehensile-tailed and nonprehensile long-tailed taxa. Results are strongly influenced by phylogeny. Corroborating previous studies, Epipliopithecus vindobonensis was reconstructed as tailless, Archaeolemur edwardsi as long-tailed, Megaladapis grandidieri as nonprehensile short-tailed, and Palaeopropithecus kelyus as nonprehensile short-tailed or tailless. Results indicate that, in the context of phylogenetic clade, measures of cortical bone cross-sectional thickness can be used to allocate extinct primate species to tail type categories. © 2017 Wiley Periodicals, Inc.

Intrinsic flux pinning mechanisms in different thickness MgB2 films

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C. Yang

2017-03-01

Full Text Available MgB2 films in four thickness (60 nm, 200nm, 600nm and 1μm have been fabricated by hybrid physical–chemical vapor deposition technique (HPCVD. By measuring the magnetization hysteresis loops and the resistivity, we have obtained the transport and magnetic properties of the four films. After that, the pinning mechanisms in them were discussed. Comparing the pinning behaviors in these ultrathin films, thin films and thick films, it was found that there exist different pinning types in MgB2 films of different thickness. In combination with the study of the surface morphology, cross-section and XRD results, we concluded that MgB2 films had different growth modes in different growth stages. For thin films, films grew along c axis, and grain boundaries acted as surface pinning. While for thick films, films grew along c axis at first, and then changed to a-b axis growth. As a result, the a-b axis grains acted as strong volume pinning.

Essaying the mechanical hypothesis: Descartes, La Forge, and Malebranche on the formation of birthmarks.

Science.gov (United States)

Wilkin, Rebecca M

2008-01-01

This essay examines the determination by Cartesians to explain the maternal imagination's alleged role in the formation of birthmarks and the changing notion of monstrosity. Cartesians saw the formation of birthmarks as a challenge through which to demonstrate the heuristic capacity of mechanism. Descartes claimed to be able to explain the transmission of a perception from the mother's imagination to the fetus' skin without having recourse to the little pictures postulated by his contemporaries. La Forge offered a detailed account stating that the failure to explain the maternal imagination's impressions would cast doubt on mechanism. Whereas both characterized the birthmark as a deformation or monstrosity in miniature, Malebranche attributed a role to the maternal imagination in fashioning family likenesses. However, he also charged the mother's imagination with the transmission of original sin.

Peripapillary retinal nerve fiber layer and choroidal thickness in cirrhosis patients

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M.Orcun Akdemir

2015-12-01

Full Text Available ABSTRACT Purpose: To evaluate the effect of cirrhosis on peripapillary retinal nerve fiber layer and choroidal thickness with enhanced depth imaging optical coherence tomography. Methods: This cross sectional, single center study was undertaken at Bulent Ecevit University Ophthalmology department with the participation of internal medicine, Gastroenterology department. Patients who were treated with the diagnosis of cirrhosis (n=75 were examined in the ophthalmology clinic. Age and sex matched patients (n=50 who were healthy and met the inclusion, exclusion criteria were included in the study. Complete ophthalmological examination included visual acuity with Snellen chart, intraocular pressure measurement with applanation tonometry, biomicroscopy of anterior and posterior segments, gonioscopy, axial length measurement, visual field examination, peripapillary retinal nerve fiber layer, central macular and subfoveal choroidal thickness measurements. Results: The difference between intraocular pressure values was not statistically significant between cirrhosis and control group (p=0.843. However, mean peripapillary retinal nerve fiber layer thickness was significantly thinner in cirrhosis group in all regions (p<0.001 and subfoveal choroidal thickness was significantly thinner in cirrhosis group also (p<0.001. Moreover, central macular thickness of cirrhosis group was significantly thicker than the control group (p=0.001. Conclusion: Peripapillary retinal nerve fiber layer and subfoveal choroidal thickness was significantly thinner in cirrhosis patients.

A apropriação de imagens de arquivo na obra de Harun Farocki e Péter Forgács

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Jamer Guterres de Mello

2012-12-01

Full Text Available This paper aims to discuss the use of archival and found footage as aprocedure whose objective is to stand out aesthetical and discursive singularities thatmisplace images original senses and create new senses for them. For this purpose, someaspects of the filmography of Harun Farocki and Péter Forgács will be analyzed. These twoartists have been adopting this gesture of appropriation, causing the re-signification of theoriginal meanings of the images.Keywords:

Calculated /alpha/-induced thick target neutron yields and spectra, with comparison to measured data

International Nuclear Information System (INIS)

Wilson, W.B.; Bozoian, M.; Perry, R.T.

1988-01-01

One component of the neutron source associated with the decay of actinide nuclides in many environments is due to the interaction of decay /alpha/ particles in (/alpha/,n) reactions on low Z nuclides. Measurements of (/alpha/,n) thick target neutron yields and associated neutron spectra have been made for only a few combinations of /alpha/ energy and target nuclide or mixtures of actinide and target nuclides. Calculations of thick target neutron yields and spectra with the SOURCES code require /alpha/-energy-dependent cross sections for (/alpha/,n) reactions, as well as branching fractions leading to the energetically possible levels of the product nuclides. A library of these data has been accumulated for target nuclides of Z /le/ 15 using that available from measurements and from recent GNASH code calculations. SOURCES, assuming neutrons to be emitted isotopically in the center-of-mass system, uses libraries of /alpha/ stopping cross sections, (/alpha/,n) reaction cross reactions, product nuclide level branching fractions, and actinide decay /alpha/ spectra to calculate thick target (/alpha/,n) yields and neutron spectra for homogeneous combinations of nuclides. The code also calculates the thick target yield and angle intergrated neutron spectrum produced by /alpha/-particle beams on targets of homogeneous mixtures of nuclides. Illustrative calculated results are given and comparisons are made with measured thick target yields and spectra. 50 refs., 1 fig., 2 tabs

Comparing electron tomography and HRTEM slicing methods as tools to measure the thickness of nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Alloyeau, D., E-mail: alloyeau.damien@gmail.com [Laboratoire Materiaux et Phenomenes Quantiques, Universite Paris 7/CNRS, UMR 7162, 2 Place Jussieu, 75251 Paris (France); Laboratoire d' Etude des Microstructures - ONERA/CNRS, UMR 104, B.P. 72, 92322 Chatillon (France); Ricolleau, C. [Laboratoire Materiaux et Phenomenes Quantiques, Universite Paris 7/CNRS, UMR 7162, 2 Place Jussieu, 75251 Paris (France); Oikawa, T. [Laboratoire Materiaux et Phenomenes Quantiques, Universite Paris 7/CNRS, UMR 7162, 2 Place Jussieu, 75251 Paris (France); JEOL (Europe) SAS, Espace Claude Monet, 1 Allee de Giverny, 78290 Croissy-sur-Seine (France); Langlois, C. [Laboratoire Materiaux et Phenomenes Quantiques, Universite Paris 7/CNRS, UMR 7162, 2 Place Jussieu, 75251 Paris (France); Le Bouar, Y.; Loiseau, A. [Laboratoire d' Etude des Microstructures - ONERA/CNRS, UMR 104, B.P. 72, 92322 Chatillon (France)

2009-06-15

Nanoparticles' morphology is a key parameter in the understanding of their thermodynamical, optical, magnetic and catalytic properties. In general, nanoparticles, observed in transmission electron microscopy (TEM), are viewed in projection so that the determination of their thickness (along the projection direction) with respect to their projected lateral size is highly questionable. To date, the widely used methods to measure nanoparticles thickness in a transmission electron microscope are to use cross-section images or focal series in high-resolution transmission electron microscopy imaging (HRTEM 'slicing'). In this paper, we compare the focal series method with the electron tomography method to show that both techniques yield similar particle thickness in a range of size from 1 to 5 nm, but the electron tomography method provides better statistics since more particles can be analyzed at one time. For this purpose, we have compared, on the same samples, the nanoparticles thickness measurements obtained from focal series with the ones determined from cross-section profiles of tomograms (tomogram slicing) perpendicular to the plane of the substrate supporting the nanoparticles. The methodology is finally applied to the comparison of CoPt nanoparticles annealed ex situ at two different temperatures to illustrate the accuracy of the techniques in detecting small particle thickness changes.

Longitudinal changes in cortical thickness in autism and typical development.

Science.gov (United States)

Zielinski, Brandon A; Prigge, Molly B D; Nielsen, Jared A; Froehlich, Alyson L; Abildskov, Tracy J; Anderson, Jeffrey S; Fletcher, P Thomas; Zygmunt, Kristen M; Travers, Brittany G; Lange, Nicholas; Alexander, Andrew L; Bigler, Erin D; Lainhart, Janet E

2014-06-01

The natural history of brain growth in autism spectrum disorders remains unclear. Cross-sectional studies have identified regional abnormalities in brain volume and cortical thickness in autism, although substantial discrepancies have been reported. Preliminary longitudinal studies using two time points and small samples have identified specific regional differences in cortical thickness in the disorder. To clarify age-related trajectories of cortical development, we examined longitudinal changes in cortical thickness within a large mixed cross-sectional and longitudinal sample of autistic subjects and age- and gender-matched typically developing controls. Three hundred and forty-five magnetic resonance imaging scans were examined from 97 males with autism (mean age = 16.8 years; range 3-36 years) and 60 males with typical development (mean age = 18 years; range 4-39 years), with an average interscan interval of 2.6 years. FreeSurfer image analysis software was used to parcellate the cortex into 34 regions of interest per hemisphere and to calculate mean cortical thickness for each region. Longitudinal linear mixed effects models were used to further characterize these findings and identify regions with between-group differences in longitudinal age-related trajectories. Using mean age at time of first scan as a reference (15 years), differences were observed in bilateral inferior frontal gyrus, pars opercularis and pars triangularis, right caudal middle frontal and left rostral middle frontal regions, and left frontal pole. However, group differences in cortical thickness varied by developmental stage, and were influenced by IQ. Differences in age-related trajectories emerged in bilateral parietal and occipital regions (postcentral gyrus, cuneus, lingual gyrus, pericalcarine cortex), left frontal regions (pars opercularis, rostral middle frontal and frontal pole), left supramarginal gyrus, and right transverse temporal gyrus, superior parietal lobule, and

Enamel thickness after preparation of tooth for porcelain laminate.

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Pahlevan, Ayoub; Mirzaee, Mansoreh; Yassine, Esmaeil; Ranjbar Omrany, Ladan; Hasani Tabatabaee, Masumeh; Kermanshah, Hamid; Arami, Sakineh; Abbasi, Mehdy

2014-07-01

In this investigation the thickness of enamel in the gingival, middle, and incisal thirds of the labial surface of the anterior teeth were measured regarding preparation of the teeth for porcelain laminate veneers. Part one, 20 extracted intact human maxillary central and lateral incisors ten of each were selected. The teeth were imbedded in autopolimerize acrylic resin. Cross section was preformed through the midline of the incisal, middle and cervical one-third of the labial surface of the teeth. The samples were observed under reflected stereomicroscope and the thickness of enamel was recorded. Part II, the effect of different types of preparation on dentin exposure was evaluated. Thirty maxillary central incisor teeth were randomly divided into two groups: A: Knife-edge preparation. B: Chamfer preparation. All samples were embedded in autopolimerize acrylic resin using a silicon mold. The samples were cut through the midline of the teeth. The surface of the samples were polished and enamel and dentin were observed under the stereomicroscope. Data were analyzed by ANOVA-one way test. The results of this study showed that the least enamel thickness in the central incisor was 345 and in lateral incisor is 235 μ this thickness is related to the one-third labial cervical area. Maximum thickness in maxillary central and lateral incisors in the one-third labial incisal surface was 1260 μ and 1220μ, respectively. In the second part of the study, the tendency of dentinal exposure was shown with the chamfer preparation, but no dentinal exposure was found in the knife-edge preparation. The differences between groups were significant (p<0.05). The knowledge of enamel thickness in different part of labial surface is very important. The thickness of enamel in the gingival area does not permit a chamfer preparation. The knife edge preparation is preferable in gingival area.

Enamel thickness after preparation of tooth for porcelain laminate.

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Ayoub Pahlevan

2014-08-01

Full Text Available In this investigation the thickness of enamel in the gingival, middle, and incisal thirds of the labial surface of the anterior teeth were measured regarding preparation of the teeth for porcelain laminate veneers.Part one, 20 extracted intact human maxillary central and lateral incisors ten of each were selected. The teeth were imbedded in autopolimerize acrylic resin. Cross section was preformed through the midline of the incisal, middle and cervical one-third of the labial surface of the teeth. The samples were observed under reflected stereomicroscope and the thickness of enamel was recorded. Part II, the effect of different types of preparation on dentin exposure was evaluated. Thirty maxillary central incisor teeth were randomly divided into two groups: A: Knife-edge preparation. B: Chamfer preparation. All samples were embedded in autopolimerize acrylic resin using a silicon mold. The samples were cut through the midline of the teeth. The surface of the samples were polished and enamel and dentin were observed under the stereomicroscope.Data were analyzed by ANOVA-one way test. The results of this study showed that the least enamel thickness in the central incisor was 345 and in lateral incisor is 235 μ this thickness is related to the one-third labial cervical area. Maximum thickness in maxillary central and lateral incisors in the one-third labial incisal surface was 1260 μ and 1220μ, respectively. In the second part of the study, the tendency of dentinal exposure was shown with the chamfer preparation, but no dentinal exposure was found in the knife-edge preparation. The differences between groups were significant (p<0.05.The knowledge of enamel thickness in different part of labial surface is very important. The thickness of enamel in the gingival area does not permit a chamfer preparation. The knife edge preparation is preferable in gingival area.

Lubricant influence on the ejection and roughness of in-die electro sinter forged Ti-discs

DEFF Research Database (Denmark)

Cannella, Emanuele; Nielsen, Chris Valentin

2018-01-01

Electro Sinter Forging (ESF) is a new sintering process based on Joule heating by high electrical current flowing through compacted metal powder under mechanical pressure. The whole process takes about three seconds and is based on a closed-die setup, where the sample is sintered inside a die....... A near-net shape component is therefore manufactured. One of the challenges associated with this process is the ejection of the sample after sintering. Due to powder compaction and axial loading during sintering, a radial pressure is generated at the die/sample interface. Consequently, the ejection can...... of commercially pure titanium powder. The force was measured while ejecting the samples by using a speed-controlled press. The surface roughness parameter Sa was measured by using a laser confocal microscope....

Free and Forced Vibrations of Thick-Walled Anisotropic Cylindrical Shells

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Marchuk, A. V.; Gnedash, S. V.; Levkovskii, S. A.

2017-03-01

Two approaches to studying the free and forced axisymmetric vibrations of cylindrical shell are proposed. They are based on the three-dimensional theory of elasticity and division of the original cylindrical shell with concentric cross-sectional circles into several coaxial cylindrical shells. One approach uses linear polynomials to approximate functions defined in plan and across the thickness. The other approach also uses linear polynomials to approximate functions defined in plan, but their variation with thickness is described by the analytical solution of a system of differential equations. Both approaches have approximation and arithmetic errors. When determining the natural frequencies by the semi-analytical finite-element method in combination with the divide and conqure method, it is convenient to find the initial frequencies by the finite-element method. The behavior of the shell during free and forced vibrations is analyzed in the case where the loading area is half the shell thickness

COMPARISON OF RNFL THICKNESS AND VISUAL FIELD CHANGES BETWEEN DIABETIC WITHOUT RETINOPATHY AND NONDIABETIC CONTROLS- A CROSS-SECTIONAL STUDY

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Soumya Swarup Chattopadhyay

2017-10-01

Full Text Available BACKGROUND Diabetes mellitus is one of the major component of metabolic syndrome and a leading cause of ocular morbidity in modern era and India will be considered to be the diabetes capital of the world. Before the onset of diabetic retinopathy, other structural and functional changes may predict the visual diminution of the individual. MATERIALS AND METHODS In this cross-sectional study in a tertiary care hospital, after inclusion and exclusion, the age-gender matched groups (diagnosed type 2 diabetes patients without diabetic retinopathy and controls without diabetes were thoroughly examined clinically and by noninvasive and invasive examination (after proper counselling of the patient and informed consent. Then, they are tested for functional loss of retina by Humphrey FDT, GDx VCC. Comparison done between cases and controls as well as poorly-controlled and well-controlled diabetic groups. RESULTS It was found that the average RNFL thickness was significantly reduced in diabetics (mean 53.48, SD 2.69 compared to controls (mean 60.21, SD 1.87 (p7%, the RNFL thickness was significantly reduced (mean 52.23, SD 1.31 compared to diabetics with good metabolic control (mean 56.38, SD 2.92 (p<0.05. In retinal functional testing, it was found that the Humphrey FDT mean deviation (FDT MD and pattern standard deviation (FDT PSD were significantly worse in diabetics (FDT MD- 1.478, SD 0.386, (FDT PSD- 3.485, SD 0.403 compared to normal controls (FDT MD- 0.442, SD 0.536, (FDT PSD- 1.438, SD 0.404. The parameters were also found to be significantly worse in uncontrolled diabetics (p<0.05. CONCLUSION To conclude, without diabetic retinopathy, functional and structural loss in retina in diabetes patients compared to age-sex matched individual and especially in poorly-controlled diabetes should be of concern as there are no detectable vasculopathy. So, early diagnosis and control of diabetes is advocated to control this functional loss

Texture Adaption in Dysphagia: Acceptability Differences Between Thickened and Naturally Thick Beverages.

Science.gov (United States)

Gerschke, Marco; Seehafer, Peggy