WorldWideScience

Sample records for cementless forged titanium

  1. Titanium and titanium alloy forgings

    International Nuclear Information System (INIS)

    The specification covers nine grades of annealed titanium and titanium alloy forgings as follows: Grade F-1, F-2, F-3, and F-4 unalloyed titanium; Grade F-5 titanium alloy (6% aluminum, 4% vanadium); Grade F-6 titanium alloy (5% aluminum, 2.5% tin); Grade F-7 and F-11 unalloyed titanium plus palladium; Grade F-12 titanium alloy (0.3% molybdenum, 0.8% nickel). The specification includes ordering information, manufacture, chemical requirements, mechanical requirements, nondestructive tests, dimensions and permissible variations, finish, certification, packaging, and marking

  2. Initial mechanical stability of cementless highly-porous titanium tibial components

    Energy Technology Data Exchange (ETDEWEB)

    Stone, Timothy Brandon [Los Alamos National Laboratory; Amer, Luke D [Los Alamos National Laboratory; Warren, Christopher P [Los Alamos National Laboratory; Cornwell, Phillip [Los Alamos National Laboratory; Meneghini, R Michael [UNIV OF CONNECTICUT HEALTH CENTER

    2008-01-01

    Cementless fixation in total knee replacement has seen limited use since reports of early failure surfaced in the late 80s and early 90s. However the emergence of improved biomaterials, particularly porous titanium and tantalum, has led to a renewed interest in developing a cementless tibial component to enhance long-term survivorship of the implants. Cement is commonly employed to minimize micromotion in new implants but represents a weak interface between the implant and bone. The elimination of cement and application of these new biomaterials, which theoretically provide improved stability and ultimate osseointegration, would likely result in greater knee replacement success. Additionally, the removal of cement from the procedure would help minimize surgical durations and get rid of the time needed for curing, thereby the chance of infection. The purpose of this biomechanical study was twofold. The first goal was to assess whether vibration analysis techniques can be used to evaluate and characterize initial mechanical stability of cementless implants more accurately than the traditional method of micromotion determination, which employs linear variable differential transducers (LVDTs). Second, an evaluative study was performed to determine the comparative mechanical stability of five designs of cementless tibial components under mechanical loading designed to simulate in vivo forces. The test groups will include a cemented Triathlon Keeled baseplate control group, three different 2-peg cementless baseplates with smooth, mid, and high roughnesses and a 4-peg cement/ess baseplate with mid-roughness.

  3. Research on the Influence of Technological Forging Parameters on the Quality of Biphasic Titanium Alloys

    Science.gov (United States)

    Mashekov, S. A.; Smaylova, N. T.; Alshynova, A. M.; Mashekova, A. S.

    2015-12-01

    The deflected mode (DM) during the preparation of the broach in the flat and combined baizes and also on radial forging machine (RFM) was investigated for creating the rational technology of a broach and determining the optimum size of the angles of rotation and single squeeze reduction. The quantitative data was obtained by the method of final elements and the MSC.Super Forge program; the main consistent patterns of stress-strain state (SSS) distribution and temperature while modeling forging in flat and combined baizes, also on RFM with various angles of rotation and sizes of squeeze reduction were determined. The rational trial technology of forging of biphasic titanium alloys was developed and tested.

  4. Formation and Microstructure of Ultrafine-Grained Titanium Processed by Multi-Directional Forging

    Science.gov (United States)

    Wang, Bingfeng; Wang, Xiaoyan; Li, Juan

    2016-06-01

    Ultrafine-grained titanium with uniform grain size for medical applications is obtained by multi-directional forging at 773 K in air. The microstructures and microtextures in the deformed titanium specimens are investigated by optical microscopy, electron backscattered diffraction technique, and transmission electron microscopy. Titanium specimen experience the recrystallization softening at cumulative strain about 1.2. After six passes with the cumulative strains of 2.4, the coarse grain sizes are gradually refined from about 25 μm to about 0.2 μm. New microtextures with recrystallized features generate in the specimens after multi-directional forgings. Grain boundaries in the specimens are geometrical necessary boundaries aiming to accommodate the imposed strain. It is suggested that the continuous dynamic recrystallization induced by deformation bands is responsible for the formation of ultrafine-grained titanium during multi-directional forging. Meanwhile the subdivision of grains by the mechanical twinning dramatically enhanced grain refinement to develop ultrafine-grained microstructure.

  5. 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.

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

    International Nuclear Information System (INIS)

    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.

  7. Cementless Titanium Mesh Fixation of Osteoporotic Burst Fractures of the Lumbar Spine Leads to Bony Healing: Results of an Experimental Sheep Model

    Science.gov (United States)

    Roepenack, Paula; Roesner, Jan; Herlyn, Philipp Karl Ewald; Martin, Heiner; Reichel, Martin; Rotter, Robert; Vollmar, Brigitte; Mittlmeier, Thomas; Gradl, Georg

    2016-01-01

    Introduction. Current treatment strategies for osteoporotic vertebral compression fractures (VCFs) focus on cement-associated solutions. Complications associated with cement application are leakage, embolism, adjacent fractures, and compromise in bony healing. This study comprises a validated VCF model in osteoporotic sheep in order to (1) evaluate a new cementless fracture fixation technique using titanium mesh implants (TMIs) and (2) demonstrate the healing capabilities in osteoporotic VCFs. Methods. Twelve 5-year-old Merino sheep received ovariectomy, corticosteroid injections, and a calcium/phosphorus/vitamin D-deficient diet for osteoporosis induction. Standardized VCFs (type AO A3.1) were created, reduced, and fixed using intravertebral TMIs. Randomly additional autologous spongiosa grafting (G1) or no augmentation was performed (G2, n = 6 each). Two months postoperatively, macroscopic, micro-CT and biomechanical evaluation assessed bony consolidation. Results. Fracture reduction succeeded in all cases without intraoperative complications. Bony consolidation was proven for all cases with increased amounts of callus development for G2 (58.3%). Micro-CT revealed cage integration. Neither group showed improved results with biomechanical testing. Conclusions. Fracture reduction/fixation using TMIs without cement in osteoporotic sheep lumbar VCF resulted in bony fracture healing. Intravertebral application of autologous spongiosa showed no beneficial effects. The technique is now available for clinical use; thus, it offers an opportunity to abandon cement-associated complications. PMID:27019848

  8. Cementless Titanium Mesh Fixation of Osteoporotic Burst Fractures of the Lumbar Spine Leads to Bony Healing: Results of an Experimental Sheep Model.

    Science.gov (United States)

    Eschler, Anica; Roepenack, Paula; Roesner, Jan; Herlyn, Philipp Karl Ewald; Martin, Heiner; Reichel, Martin; Rotter, Robert; Vollmar, Brigitte; Mittlmeier, Thomas; Gradl, Georg

    2016-01-01

    Introduction. Current treatment strategies for osteoporotic vertebral compression fractures (VCFs) focus on cement-associated solutions. Complications associated with cement application are leakage, embolism, adjacent fractures, and compromise in bony healing. This study comprises a validated VCF model in osteoporotic sheep in order to (1) evaluate a new cementless fracture fixation technique using titanium mesh implants (TMIs) and (2) demonstrate the healing capabilities in osteoporotic VCFs. Methods. Twelve 5-year-old Merino sheep received ovariectomy, corticosteroid injections, and a calcium/phosphorus/vitamin D-deficient diet for osteoporosis induction. Standardized VCFs (type AO A3.1) were created, reduced, and fixed using intravertebral TMIs. Randomly additional autologous spongiosa grafting (G1) or no augmentation was performed (G2, n = 6 each). Two months postoperatively, macroscopic, micro-CT and biomechanical evaluation assessed bony consolidation. Results. Fracture reduction succeeded in all cases without intraoperative complications. Bony consolidation was proven for all cases with increased amounts of callus development for G2 (58.3%). Micro-CT revealed cage integration. Neither group showed improved results with biomechanical testing. Conclusions. Fracture reduction/fixation using TMIs without cement in osteoporotic sheep lumbar VCF resulted in bony fracture healing. Intravertebral application of autologous spongiosa showed no beneficial effects. The technique is now available for clinical use; thus, it offers an opportunity to abandon cement-associated complications. PMID:27019848

  9. Cementless total hip arthroplasty with the rectangular titanium Zweymuller stem. A concise follow-up, at a minimum of fifteen years, of a previous report.

    Science.gov (United States)

    Grübl, Alexander; Chiari, Catharina; Giurea, Alexander; Gruber, Martin; Kaider, Alexandra; Marker, Martina; Zehetgruber, Harald; Gottsauner-Wolf, Florian

    2006-10-01

    Between October 1986 and November 1987, 208 total hip arthroplasties were performed with use of the cementless Zweymüller stem and a threaded cup in 200 consecutive patients. Of 102 patients (108 hips) who were available for follow-up at a minimum of 180 months postoperatively, eighty-three (eighty-nine hips) had the primary joint replacement still intact. No stem had been revised because of aseptic loosening, but we found various degrees of osteolysis around sixteen (18%) of the implants. The probability of survival of the stem at fifteen years was 0.98 (95% confidence interval, 0.96 to 1.00). The probability of survival of the cup was 0.85 (95% confidence interval, 0.79 to 0.91). PMID:17015598

  10. Achieving Fine Beta Grain Structure in a Metastable Beta Titanium Alloy Through Multiple Forging-Annealing Cycles

    Science.gov (United States)

    Zafari, Ahmad; Ding, Yunpeng; Cui, Jianzhong; Xia, Kenong

    2016-07-01

    A coarse-grained (order of 1 mm) Ti-5553 metastable beta alloy was subjected to multiple passes of low-temperature forging and multiple forging plus annealing cycles, respectively. In the forging only processing, strain was concentrated in the shear bands formed and accumulated with each forging pass, resulting in a heterogeneous microstructure and eventual cracking along the shear bands. In contrast, the introduction of a short beta annealing after each forging step led to fine recrystallized grains (50 to 100 µm) formed in the shear bands, and a uniformly refined beta grain structure after four cycles. This is attributed to the strengthening effect of the fine grains, causing redistribution of most severe strains to the coarse grain region in the subsequent forging, consistent with the simulated results by finite element analysis. The analyses of the microstructures and simulated strain distributions revealed that the critical strain for recrystallization is between 0.2 and 0.5 and the strain to fracture to be ~0.8 to 0.9. The fine-grained (50 to 100 µm) beta alloy, however, fractured at a much smaller strain of <0.4 during the next forging step, owing to the formation of stress-induced martensitic α″ which is more prevalent in fine grains than in coarse ones.

  11. Cementless Oxford unicompartmental knee replacement shows reduced radiolucency at one year.

    Science.gov (United States)

    Pandit, H; Jenkins, C; Beard, D J; Gallagher, J; Price, A J; Dodd, C A F; Goodfellow, J W; Murray, D W

    2009-02-01

    We randomised 62 knees to receive either cemented or cementless versions of the Oxford unicompartmental knee replacement. The implants used in both arms of the study were similar, except that the cementless components were coated with porous titanium and hydroxyapatite. The tibial interfaces were studied with fluoroscopically-aligned radiographs. At one year there was no difference in clinical outcome between the two groups. Narrow radiolucent lines were seen at the bone-implant interfaces in 75% of cemented tibial components. These were partial in 43%, and complete in 32%. In the cementless implants, partial radiolucencies were seen in 7% and complete radiolucencies in none. These differences are statistically significant (p < 0.0001) and imply satisfactory bone ingrowth into the cementless implants. PMID:19190051

  12. Good performance of a titanium femoral component in cementless hip arthroplasty in younger patients: 97 arthroplasties followed for 5-11 years

    DEFF Research Database (Denmark)

    Jacobsen, Steffen; Jensen, Frank Krieger; Poulsen, Klaus;

    2003-01-01

    We performed 97 uncemented primary total hip arthroplasties in 80 patients having an average age of 50 years. The femoral implant was a titanium stem with a proximal circumferential plasma spray-coating. Three different acetabular components were used: a threaded and partly porous-coated design i...

  13. Microstructural evolutions in warm compression of Betacez and 6246 titanium alloys and influence of the forging on the transformation {beta} {yields} {alpha}; Evolutions microstructurales en compression a chaud des alliages de titane Betacez et 6246 et influence du forgeage sur la transformation {beta} {yields} {alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Chaussy Mraizika, F.

    1996-06-26

    The relations between the thermomechanical ranges and the microstructures of titanium alloys are still insufficient. This work proposes to improve the knowledge of structural state coming from the {beta} forging and the ulterior transformation {beta} to {alpha}+{beta}. The influence of the two parameters, rate and strain speed, on the microstructural and textural evolutions appear during the forging and also during the {beta}/{alpha} transformation are systematically studied. The two titanium alloys which are studied are Betacez titanium alloy and the 6246 titanium alloy. (N.C.)

  14. 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

  15. Cementless Hydroxyapatite Coated Hip Prostheses

    Directory of Open Access Journals (Sweden)

    Antonio Herrera

    2015-01-01

    Full Text Available More than twenty years ago, hydroxyapatite (HA, calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality.

  16. Antibacterial Efficacy of a New Gentamicin-Coating for Cementless Prostheses Compared to Gentamicin-Loaded Bone Cement

    NARCIS (Netherlands)

    Neut, Danielle; Dijkstra, Rene J. B.; Thompson, Jonathan I.; van der Mei, Henny C.; Busscher, Henk J.

    2011-01-01

    Cementless prostheses are increasingly popular but require alternative prophylactic measures than the use of antibiotic-loaded bone cements. Here, we determine the 24-h growth inhibition of gentamicin-releasing coatings from grit-blasted and porous-coated titanium alloys, and compare their antibacte

  17. Large head metal-on-metal cementless total hip arthroplasty versus 28mm metal-on-polyethylene cementless total hip arthroplasty: design of a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    van Raaij Jos JAM

    2008-10-01

    Full Text Available Abstract Background Osteoarthritis of the hip is successfully treated by total hip arthroplasty with metal-on-polyethylene articulation. Polyethylene wear debris can however lead to osteolysis, aseptic loosening and failure of the implant. Large head metal-on-metal total hip arthroplasty may overcome polyethylene wear induced prosthetic failure, but can increase systemic cobalt and chromium ion concentrations. The objective of this study is to compare two cementless total hip arthroplasties: a conventional 28 mm metal-on-polyethylene articulation and a large head metal-on-metal articulation. We hypothesize that the latter arthroplasties show less bone density loss and higher serum metal ion concentrations. We expect equal functional scores, greater range of motion, fewer dislocations, fewer periprosthetic radiolucencies and increased prosthetic survival with the metal-on-metal articulation. Methods A randomized controlled trial will be conducted. Patients to be included suffer from non-inflammatory degenerative joint disease of the hip, are aged between 18 and 80 and are admitted for primary cementless unilateral total hip arthroplasty. Patients in the metal-on-metal group will receive a cementless titanium alloy acetabular component with a cobalt-chromium liner and a cobalt-chromium femoral head varying from 38 to 60 mm. Patients in the metal-on-polyethylene group will receive a cementless titanium alloy acetabular component with a polyethylene liner and a 28 mm cobalt-chromium femoral head. We will assess acetabular bone mineral density by dual energy x-ray absorptiometry (DEXA, serum ion concentrations of cobalt, chromium and titanium, self reported functional status (Oxford hip score, physician reported functional status and range of motion (Harris hip score, number of dislocations and prosthetic survival. Measurements will take place preoperatively, perioperatively, and postoperatively (6 weeks, 1 year, 5 years and 10 years. Discussion

  18. Cementless isoelastic RM total hip prosthesis1

    OpenAIRE

    Bombelli, Renato; Mathys, Robert

    1982-01-01

    Some surgeons are beginning to doubt the reliability of bone cement in joint replacements. In 1967 Robert Mathys conceived the idea of an isoelastic prosthesis made of plastic, which would anchor into the bone without cement. He developed the idea by extensive tests in animals and, in 1973, the first human RM cementless hip prosthesis was inserted by E Morscher. In this paper the concept of the cementless isoelastic prosthesis is developed by Robery Mathys, and Professor Bombelli records his ...

  19. Forging process design for risk reduction

    Science.gov (United States)

    Mao, Yongning

    In this dissertation, forging process design has been investigated with the primary concern on risk reduction. Different forged components have been studied, especially those ones that could cause catastrophic loss if failure occurs. As an effective modeling methodology, finite element analysis is applied extensively in this work. Three examples, titanium compressor disk, superalloy turbine disk, and titanium hip prosthesis, have been discussed to demonstrate this approach. Discrete defects such as hard alpha anomalies are known to cause disastrous failure if they are present in those stress critical components. In this research, hard-alpha inclusion movement during forging of titanium compressor disk is studied by finite element analysis. By combining the results from Finite Element Method (FEM), regression modeling and Monte Carlo simulation, it is shown that changing the forging path is able to mitigate the failure risk of the components during the service. The second example goes with a turbine disk made of superalloy IN 718. The effect of forging on microstructure is the main consideration in this study. Microstructure defines the as-forged disk properties. Considering specific forging conditions, preform has its own effect on the microstructure. Through a sensitivity study it is found that forging temperature and speed have significant influence on the microstructure. In order to choose the processing parameters to optimize the microstructure, the dependence of microstructure on die speed and temperature is thoroughly studied using design of numerical experiments. For various desired goals, optimal solutions are determined. The narrow processing window of titanium alloy makes the isothermal forging a preferred way to produce forged parts without forging defects. However, the cost of isothermal forging (dies at the same temperature as the workpiece) limits its wide application. In this research, it has been demonstrated that with proper process design, the die

  20. 锻造工艺对大规格 TC17钛合金棒材组织及性能的影响%Effect of Forging Process on Microstructure and Mechanical Properties of TC17 Titanium Alloy Bars

    Institute of Scientific and Technical Information of China (English)

    岳旭; 冯浩; 马恩惠; 李巍; 马宝军; 董洁; 李渭清

    2013-01-01

    通过两种工艺锻制了矱350 mm的大规格TC17钛合金棒材,比较了经两种工艺锻制的棒材的显微组织、力学性能及探伤杂波水平。研究结果表明,在单相区采用镦拔变形使变形量大于60%,并在两相区进行拔长,使变形量大于65%,再经840℃×2 h/AC +800℃×4 h/WC +630℃×8 h/AC 热处理,可得到各项力学性能均符合 GJB 2218 A-2008标准要求且探伤杂波水平可达矱3.2 mm -9~-12 dB的矱350 mm TC17钛合金棒材。%Forging ф350 mm TC17 titanium alloy bars through two schemes , then compared the microstructures , mechanical properties and flaw detection levels of the bars .The results show that , deformed more than 60% using upsetting and stretching forging process in single-phase region and then deformed more than 65% using stretching forging process in dual-phase region , continued with the heat treatment of 840℃×2 h/AC+800℃×4 h/WC+630℃×8 h/AC, the mechanical properties of bars could meet the GJB 2218 A-2008 standard and the flaw detection level was ф3.2 mm -9~-12 dB .

  1. Results of cementless hip arthroplasty; Ergebnisse zementfreier Hueftendoprothetik

    Energy Technology Data Exchange (ETDEWEB)

    Gruebl, A. [Medizinische Universitaet Wien, Klinik fuer Orthopaedie, Wien (Austria)

    2006-09-15

    Hip arthroplasty is performed nowadays according to the needs of the patients irrespective of their age. Tapered rectangular stems for cementless fixation are chosen in most cases in central Europe. They provide primary stability by press-fit implantation into a precisely rasped osseous bed and secondary stability by bone ingrowth into the highly biocompatible titanium alloy with a microrough surface. The 10-year survival of such devices is 92%. Typical radiographic patterns include cortical atrophy and radiolucent lines in Gruen zones 1 and 7. They are due to stress shielding with these distally fixed implants. The number one reason for revision is polyethylene wear and subsequent osteolysis. Metal-on-metal and ceramic-on-ceramic bearings show less wear but osteolysis continues to be a problem. (orig.) [German] Hueftendoprothesen werden implantiert, wenn der Patient sie, unabhaengig vom Alter, braucht. Mehrheitlich kommen rechteckige Geradschaefte zementfrei zur Anwendung. Sie gewaehrleisten eine primaer stabile Verankerung durch Press-Fitt-Implantation in ein praezise geraspeltes knoechernes Bett und sekundaere Stabilisierung durch Anwachsen von Knochen auf der mikrorauen Oberflaeche der biokompatiblen Titanlegierung. Die Zehnjahresueberlebensraten fuer solche Prothesen betraegt 92%. Typische Roentgenzeichen sind proximale kortikale Atrophie und Saeume in den Gruen-Zonen 1 und 7, die aber kein Zeichen der Lockerung darstellen. Der haeufigste Grund fuer Revisionsoperationen ist der Polyethylenabrieb und daraus resultierende Osteolysen. Moderne Gleitpaarungen wie Metall/Metall und Keramik/Keramik haben deutlich weniger Abrieb, das Problem der Osteolysen ist aber nicht geloest. (orig.)

  2. A Femur-Implant Model for the Prediction of Bone Remodeling Behavior Induced by Cementless Stem

    Institute of Scientific and Technical Information of China (English)

    He Gong; Lingyan Kong; Rui Zhang; Juan Fang; Meisheng Zhao

    2013-01-01

    Bone remodeling simulation is an effective tool for the prediction of long-term effect of implant on the bone tissue,as well as the selection of an appropriate implant in terms of architecture and material.In this paper,a finite element model of proximal femur was develop.ed to simulate the structures of internal trabecular and cortical bones by incorporating quantitative bone functional adaptation theory with finite element analysis.Cementless stems made of titanium,two types of Functionally Graded Material (FGM) and flexible 'iso-elastic' material as comparison were implanted in the structure of proximal femur respectively to simulate the bone remodeling behaviors of host bone.The distributions of bone density,von Mises stress,and interface shear stress were obtained.All the prosthetic stems had effects on the bone remodeling behaviors of proximal femur,but the degrees of stress shielding were different.The amount of bone loss caused by titanium implant was in agreement with the clinical observation.The FGM stems caused less bone loss than that of the titanium stem,in which FGM I stem (titanium richer at the top to more HAP/Col towards the bottom) could relieve stress shielding effectively,and the interface shear stresses were more evenly distributed in the model with FGM I stem in comparison with those in the models with FGM II (titanium and bioglass) and titanium stems.The numerical simulations in the present study provided theoretical basis for FGM as an appropriate material of femoral implant from a biomechanical point of view.The next steps are to fabricate FGM stem and to conduct animal experiments to investigate the effects of FGM stem on the remodeling behaviors using animal model.

  3. Modified cementless total coxofemoral prosthesis: development, implantation and clinical evaluation

    Directory of Open Access Journals (Sweden)

    S.A. Arias

    2013-12-01

    Full Text Available The aim of this study was to modify canine coxofemoral prostheses and the clinical evaluation of the implantation. Fifteen canine hips and femora of cadavers were used in order to study the surface points of modification in prostheses and develop a perforation guide. Femoral stems and acetabular components were perforated and coated with biphasic calcium phosphate layer. Twelve young adult male mongrel dogs were implanted with coxofemoral prostheses. Six were operated upon and implanted with cemented canine modular hip prostheses, establishing the control group. The remaining six were implanted with a novel design of cementless porous tricalcic phosphate-hydroxyapatite coated hip prostheses. Clinical and orthopedic performance, complications, and thigh muscular hypotrophy were assessed up to the 120th post-operatory day. After 120 days, animals with cementless prostheses had similar clinical and orthopedic performance compared to the cemented group despite the increased pain thigh hypotrophy. Animals that underwent cementless hip prosthesis evidenced more pain, compared to animals with cemented hip prosthesis that required longer recuperation time. No luxations, two fractures and two isquiatic neurapraxies were identified in the course of the study. Using both the cemented and the bioactive coated cementless model were suitable to dogs, showing clinical satisfactory results. Osseointegration and biological fixation were observed in the animals with the modified cementless hip prosthesis.

  4. Modeling of Closed-Die Forging for Estimating Forging Load

    Science.gov (United States)

    Sheth, Debashish; Das, Santanu; Chatterjee, Avik; Bhattacharya, Anirban

    2016-05-01

    Closed die forging is one common metal forming process used for making a range of products. Enough load is to exert on the billet for deforming the material. This forging load is dependent on work material property and frictional characteristics of the work material with the punch and die. Several researchers worked on estimation of forging load for specific products under different process variables. Experimental data on deformation resistance and friction were used to calculate the load. In this work, theoretical estimation of forging load is made to compare this value with that obtained through LS-DYNA model facilitating the finite element analysis. Theoretical work uses slab method to assess forging load for an axi-symmetric upsetting job made of lead. Theoretical forging load estimate shows slightly higher value than the experimental one; however, simulation shows quite close matching with experimental forging load, indicating possibility of wide use of this simulation software.

  5. Three-dimensional model of cementless acetabular cup migration

    Czech Academy of Sciences Publication Activity Database

    Jíra, J.; Jiroušek, Ondřej; Jírová, Jitka; Micka, Michal

    Lisbon : CivilComp Press, 2004 - (Tooping, B.; Mota Soares, C.), s. 699 ISBN 0-948749-93-8. [The Seventh International Conference on Computational Structures Technology. Lisabon (PT), 07.09.2004-09.09.2004] Institutional research plan: CEZ:AV0Z2071913 Keywords : loosening and migration of cementless acetabular cup * pelvis * FE model Subject RIV: FI - Traumatology, Orthopedics

  6. Short term results of cementless total hip arthroplasty in sicklers

    Directory of Open Access Journals (Sweden)

    Yash Gulati

    2015-01-01

    Conclusion: THA in sicklers involves considerable challenge for the orthopedic surgeon. Management requires a multidisciplinary approach involving the anesthetist, hematologist and the orthopedic surgeon. Contrary to previous reports, THA in sicklers now has a predictable outcome especially with the use of cementless implants.

  7. Relationship among forging technology, structure and properties of TC21 alloy bars

    Institute of Scientific and Technical Information of China (English)

    QU Heng-lei; LI Hui; ZHANG Ying-nan; GUO Hong-chao; ZHOU Yi-gang; ZHOU Lian; ZHAO Yong-qing; ZENG Wei-dong; FENG Liang; YANG Yan-qing; CHEN Jun; YU Han-qing

    2005-01-01

    As candidate of structural material for advanced domestic aircraft, a new high strength and toughness titanium alloy TC21 was studied focusing on forging technology and microstructure as well as mechanical properties.Two specification ingots and bars were adopted. The results show that basket-weave microstructure is obtained in bars produced by beta finish-forging method; while duplex or tri-modal microstructure appears in bars manufactured by near-beta forging technology. Essential reason affecting structure characteristics is the difference in forging tem perature and deformation amount. Variation in lamellar spacing results in fluctuation of properties corresponding to basket-weave microstructure; however, ideal matching of properties can be reached by near-beta forging.

  8. Cementless Hip Arthroplasty in Southern Iran, Midterm Outcome and Comparison of Two Designs

    OpenAIRE

    Gholam Hossein Shahcheraghi; Seyed Ali Hashemi

    2015-01-01

    Background: Cementless hip prosthesis was designed to provide biologic fixation, without the use of cement. The second generation components have shown more reliable bone ingrowths and survival rates. We are reporting a midterm result of two designs of cementless prosthesis in a unique culture with different social habits and expectations. Methods: 52 primary cementless total hip arthroplasty in 42 patients with the mean age of 48.8 years were retrospectively studied. Two groups of prosthe...

  9. PRIMARY CEMENTLESS TOTAL HIP ARTHROPLASTY IN ANKYLOSING SPONDYLITIS

    OpenAIRE

    Nageshwara Rao; Ravikumar

    2015-01-01

    INTRODUCTION Ankylosing Spondylitis (AS), family of Spondyloarthritides (SpAs), is a chronic inflammatory disease affecting the axial skeleton, the entheses and occasionally the peripheral joints. The shoulders and hips are considered axial joints and involvement occurs in up to 50% of patients and is more common than involvement of the more distal joints. Aim of our study is to evaluate outcome of Cementless Total Hip Arthroplasty (THA) in ankylosing spondylitis. MAT...

  10. Immediate Cementless Hemiarthroplasty for Severe Destructive Glenohumeral Tuberculous Arthritis

    OpenAIRE

    Suriya Luenam; Arkaphat Kosiyatrakul

    2013-01-01

    The glenohumeral joint tuberculosis (TB) is rare as compared with other joints. Plaster immobilization, arthrodesis, and resection arthroplasty have been proposed as the additional treatments with anti-TB medications in severe destructive arthritis. To our knowledge, however, the surgical treatment with shoulder arthroplasty has never been reported. We present two cases of active TB with unsalvageable glenohumeral joint. The cementless hemishoulder arthroplasties were performed immediately fo...

  11. PRIMARY CEMENTLESS TOTAL HIP ARTHROPLASTY IN ANKYLOSING SPONDYLITIS

    Directory of Open Access Journals (Sweden)

    Nageshwara Rao

    2015-12-01

    Full Text Available INTRODUCTION Ankylosing Spondylitis (AS, family of Spondyloarthritides (SpAs, is a chronic inflammatory disease affecting the axial skeleton, the entheses and occasionally the peripheral joints. The shoulders and hips are considered axial joints and involvement occurs in up to 50% of patients and is more common than involvement of the more distal joints. Aim of our study is to evaluate outcome of Cementless Total Hip Arthroplasty (THA in ankylosing spondylitis. MATERIALS AND METHODS We prospectively and retrospectively reviewed 27 hips in 20 patients who underwent cementless THA between 2007-2013. Mean age of patient was 31.5 years. We analysed demographic data, preoperative deformity, Harris Hip Score, ambulatory status, need for walking aids. RESULTS All patients experienced significant improvement in function, range of motion, posture and ambulation. Postoperative Harris Hip Score improved from 18.95 to 89.35; 90% are completely pain free, 5% have occasional discomfort and 5% have mild-to-moderate pain. CONCLUSION Cementless THA for deformed hips in young patients with AS is worthwhile surgical intervention, as it increases the mobility of the patient, improves the ability to sit comfortably, decrases the morbidity of the disease. However, the technically demanding nature of the procedure should not be underestimated.

  12. Utilization of titanium chips

    International Nuclear Information System (INIS)

    Complex of equipment is created for realization of developed technology in experimental-inductrial production of secondary titanium alloys with annual efficiency of 50-100 t. The complex includes a section for chips preparation, facility for electride vacuum hot pressins, vacuum arc furnace for melting ingots of <200 kg. The ingots obtained will be reprocessed into bars, forgins, powers and also be used for production of shaped castings. Approbation of the developed technology was carried out by production of three types of secondary titanium lloys. The technical titanium chips were used as blend for production of TV1 alloy, chips of VT5 and PT3V alloys for TV2 and chips of VT6 and VT23 alloys for TV3 alloys. Study of chemical composition, mechanical properties and structure of secondary titanium alloys were performed on forged bars 20 mm in diameter

  13. Bone ingrowth through porous titanium granulate around a femoral stem: histological assessment in a six-month canine hemiarthroplasty model.

    Science.gov (United States)

    Turner, Thomas M; Urban, Robert M; Hall, Deborah J; Andersson, Gunnar B J

    2007-01-01

    The procedure of using of porous titanium granules for cementless fixation of a hip replacement femoral stem was studied in a hemiarthroplasty model in 10 canines for 6 months. A vibrating instrument was used to facilitate both the delivery and distribution of the irregularly shaped porous titanium granules into the femoral canal as well as the subsequent insertion of a titanium alloy stem into the intramedullary bed of granules. Histological examination revealed lamellar bone formation through the mantle of porous titanium granules in continuity with the surrounding cortex resulting in the formation of an integrated mantle of bone and titanium granulate around the prosthesis. PMID:17578819

  14. Method of making multilayered titanium ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, George T., II; Hansen; Jeffrey S.; Oden; Laurance L.; Turner; Paul C.; Ochs; Thomas L.

    1998-08-25

    A method making a titanium ceramic composite involves forming a hot pressed powder body having a microstructure comprising at least one titanium metal or alloy layer and at least one ceramic particulate reinforced titanium metal or alloy layer and hot forging the hot pressed body follwed by hot rolling to substantially reduce a thickness dimension and substantially increase a lateral dimension thereof to form a composite plate or sheet that retains in the microstructure at least one titanium based layer and at least one ceramic reinforced titanium based layer in the thickness direction of the composite plate or sheet.

  15. Forging evaluaion of 304L stainless steel

    International Nuclear Information System (INIS)

    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 11450C, upset reductions ranging from 20 to 60%, and annealing times ranging from 0 to 25 minutes at 8430C. 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 8430C promoted increased carbide precipitation. The yield strength of the unannealed forgings decreased with increasing forging temperature and, with the exception of the 11450C upset forgings, was significantly lowered by annealing

  16. The evaluation of Ontario Forge Company as a qualified forging vendor

    Energy Technology Data Exchange (ETDEWEB)

    West, A.J.; Odegard, B.C.

    1981-10-12

    There has been a long standing need to develop a second source of WR quality forgings for the manufacturing of J-line hardware at RF. With this objective, Ontario Forge Company was recently evaluated to determine if their equipment and skills were compatible with the forging requirements. The results of this evaluation were compared to test results on WR forgings of a similar design produced by Precision Forge Company. The Ontario Forge Company forgings exhibited mechanical properties, grain flow and microstructures equivalent to those of Precision Forge Company. The Ontario Forge Company performance on this contract justifies the qualification of their process for producing non-critical reservoir forgings. Qualifying Ontario Forge Company for critical reservoir forgings is recommended only after sufficient production experience and storage data is acquired.

  17. Laser repair hardfacing of titanium alloy turbine

    OpenAIRE

    A. Klimpel; D. Janicki; A. Lisiecki; A. Rzeźnikiewicz

    2011-01-01

    Purpose: of this paper: work out repair technology of worn abutments of aircraft jet engine blades forged of titanium alloy WT3-1.Design/methodology/approach: The study were based on the analysis of laser HPDL powder surfacing of titanium alloy plates using wide range chemical composition consumables of titanium alloys and mixtures of pure titanium and spherical powder of WC indicated that very hard and highest quality deposits are provided by powder mixture of 40-50%Ti+60-50%WC.Findings: It ...

  18. Surface composition analysis of failed cementless CoCr- and Ti-base-alloy total hip implants.

    Science.gov (United States)

    Decking, R; Reuter, P; Hüttner, M; Puhl, W; Claes, L E; Scharf, H P

    2003-02-15

    The surfaces of retrieved failed cementless total hip implants made of cobalt-chromium-molybdenum casting alloy and of wrought titanium 6-aluminum 4-vanadium alloy were studied with the use of scanning-electron microscopy (SEM), energy-dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS). New implants of the same make served as controls. The XPS scans revealed a dense carbon layer on the entire analyzed specimen. The relative composition of the titanium alloy implants showed an overall agreement with the international standards for implants for surgery, and the overall surface composition did not change over the period of the implantation. However, an inhomogeneous distribution of the constituents could be demonstrated in the retrieved as well as in the new MEC-screw rings made of TiAl6V4 alloy, an implant that has been linked to a high early failure rate. In the CoCr-alloy components (Lord-screw rings) a high percentage of aluminum, mainly organized in aluminum inclusions, was found in the retrieved as well as in the new implants. PMID:12516084

  19. Heavy forgings for reactor pressure vessels

    International Nuclear Information System (INIS)

    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.)

  20. Superior fixation of pegged trabecular metal over screw-fixed pegged porous titanium fiber mesh

    OpenAIRE

    Stilling, Maiken; Madsen, Frank; Odgaard, Anders; Rømer, Lone; Andersen, Niels Trolle; Rahbek, Ole; Søballe, Kjeld

    2011-01-01

    Background and purpose Lasting stability of cementless implants depends on osseointegration into the implant surface, and long-term implant fixation can be predicted using radiostereometric analysis (RSA) with short-term follow-up. We hypothesized that there would be improved fixation of high-porosity trabecular metal (TM) tibial components compared to low-porosity titanium pegged porous fiber-metal (Ti) polyethylene metal backings. Methods In a prospective, parallel-group, randomized unblind...

  1. Inferior Survival of Hydroxyapatite versus Titanium-coated Cups at 15 Years

    OpenAIRE

    Stilling, Maiken; Rahbek, Ole; Søballe, Kjeld

    2009-01-01

    Hydroxyapatite (HA) particles have long been suspected to disintegrate from implant surfaces, become entrapped in joint spaces of orthopaedic bearing couples, and start a cascade leading to progressive polyethylene (PE) wear, increased osteolysis, and aseptic loosening. We compared cup revision at 15 years’ followup in a randomized group of patients with 26 cementless THA components with titanium (Ti) versus first-generation HA coating. We also assessed radiographic PE wear and osteolysis to ...

  2. Artificial neural network modeling of phase volume fraction of Ti alloy under isothermal and non-isothermal hot forging conditions

    International Nuclear Information System (INIS)

    An artificial neural network (ANN) model was applied to simulate the phase volume fraction of titanium alloy under isothermal and non-isothermal hot forging condition. For isothermal hot forging process, equilibrium phase volume fraction at specific temperature was predicted. For this purpose, chemical composition of six alloy elements (i.e. AI, Y, Fe, 0, N, and C) and specimen temperature were chosen as input parameter. After that, phase volume fraction under non-isothermal condition was simulated again. Input parameters consist of initial phase volume fraction, equilibrium phase volume fraction at specific temperature, cooling rate, and temperature.The ANN model was coupled with the FE simulation in order to predict the variation of phase volume fraction during non-isothermal forging. Ti-6AI-4Y alloy was forged under isothermal and non-isothermal condition and then, the resulting microstructures were compared with simulated data

  3. High-energy rate forgings of wedges :

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, Thomas Bither; Everhart, Wesley; Switzner, Nathan T; Balch, Dorian K.; San Marchi, Christopher W.

    2014-05-01

    The wedge geometry is a simple geometry for establishing a relatively constant gradient of strain in a forged part. The geometry is used to establish gradients in microstructure and strength as a function of strain, forging temperature, and quenching time after forging. This geometry has previously been used to benchmark predictions of strength and recrystallization using Sandias materials model for type 304L austenitic stainless steel. In this report, the processing conditions, in particular the times to forge and quench the forged parts, are summarized based on information recorded during forging on June 18, 2013 of the so-called wedge geometry from type 316L and 21Cr-6Ni-9Mn austenitic stainless steels.

  4. Isothermal precision forging of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy impeller with twisted blades

    Institute of Scientific and Technical Information of China (English)

    SHAN De-bin; SHI Ke; XU Wen-chen; L(U) Yan

    2006-01-01

    Ti-6.5Al-3.5Mo-1.5Zr-0.3Si (TC11) alloy impeller is an important part in the airspace engine that serves under severe working conditions, and it requires excellent mechanical properties and high dimensional precision. However, the integral titanium alloy impeller is difficult to precisely forge because of its complex shape and poor formability. In order to develop optimum forging process of this kind of complex parts, the deformation characteristics of TC11 alloy under isothermal compressing conditions were studied. Furthermore, an alternative material, namely pure lead, was selected to model the forming process of the impeller and investigate metal flow during forging. Based on the research, local loading method was determined to forge the TC11 alloy impeller precisely under isothermal condition. The dimensional accuracy, mechanical properties and microscopic structure of the forged product satisfy operating requirements.

  5. Outcomes of a Newer-Generation Cementless Total Knee Arthroplasty Design.

    Science.gov (United States)

    Harwin, Steven F; Elmallah, Randa K; Jauregui, Julio J; Cherian, Jeffrey J; Mont, Michael A

    2015-10-01

    Newer-generation cementless total knee arthroplasties (TKAs) aim to improve durability, function, and longevity. In a large series of cementless TKAs at a mean 4-year follow-up, the authors evaluated (1) survivorship, (2) range of motion, (3) patient-reported outcomes, and (4) complications. Mean age was 66 years (range, 34-88 years) and mean body mass index was 32.5 kg/m(2) (range, 20-54 kg/m(2)). Aseptic and septic implant survivorships were 99.6% and 99.5%, respectively. Mean extension, flexion, and Knee Society scores improved significantly. There were 3 septic failures. Aseptic failures included 3 aseptic loosenings, 1 polyethylene revision, and 1 revision to a cemented patella. This study showed excellent clinical and patient-reported outcomes of cementless TKA. PMID:26488775

  6. RESEARCH ON KNOWLEDGE-BASED CAPP SYSTEM FOR ROTOR FORGING

    Institute of Scientific and Technical Information of China (English)

    Wang Leigang; Deng Dongrnei; Liu Zhubai

    2000-01-01

    Guided by developing forging technology theory,designing rules on rotor forging process are summed up.Knowledge-based CAPP system for rotor forging is created.The system gives a rational and optimum process.

  7. THE HIGH VOLUME REUSE OF HYBRID BIOMASS ASH AS A PRIMARY BINDER IN CEMENTLESS MORTAR BLOCK

    Directory of Open Access Journals (Sweden)

    Cheah Chee Ban

    2014-01-01

    Full Text Available High Calcium Wood Ash (HCWA and Pulverised Fuel Ash (PFA are by-products from the wood biomass and coal energy production which are produced in large quantity with combined annual production of 500 million tonnes. This poses a serious problem for disposal of the waste material especially at places where land is scarce. The prescribed study was aimed to examine the mineralogical phases and their respective amount present in the industrial wastes which governs the hydration mechanism towards self-sustained solidification of the ashes when used in combination. Besides, the influence of various forming pressure and hydrothermal treatment temperature on mechanical strength performance of HCWA-PFA cementless mortar blocks was also examined. In the study, the mechanical strength of the HCWA-PFA cementless mortar block produced using various forming pressure and hydrothermal treatment temperature was assessed in terms of compressive strength and dynamic modulus. The results of the study are indicative that HCWA is rich in calcium oxide and potassium oxide content. This enables the hybridization of HCWA with the amorphous silica and alumina rich PFA to form a solid geopolymer binder matrix for fabrication of cementless mortar block. Throughout the study, dimensionally and mechanically stable HCWA-PFA geopolymer mortar blocks were successfully produced by press forming and hydrothermal treatment method. Based on statistical analysis, the hydrothermal treatment temperature has a statistically insignificant effect on the mechanical strength of the HCWA-PFA cementless mortar blocks. The dominant factor which governs the mechanical strength of the HCWA-PFA cementless mortar blocks was found to be the hydraulic forming pressure. Moreover, it was found that hybridized HCWA-PFA can be recycled as the sole binder for fabrication of cementless concrete block which is a useful construction material.

  8. Study of bone remodeling of two models of femoral cementless stems by means of DEXA and finite elements

    Directory of Open Access Journals (Sweden)

    López-Prats Fernando

    2010-05-01

    Full Text Available Abstract Background A hip replacement with a cemented or cementless femoral stem produces an effect on the bone called adaptive remodelling, attributable to mechanical and biological factors. All of the cementless prostheses designs try to achieve an optimal load transfer in order to avoid stress-shielding, which produces an osteopenia. Long-term densitometric studies taken after implanting ABG-I and ABG-II stems confirm that the changes made to the design and alloy of the ABG-II stem help produce less proximal atrophy of the femur. The simulation with FE allowed us to study the biomechanical behaviour of two stems. The aim of this study was, if possible, to correlate the biological and mechanical findings. Methods Both models with prostheses ABG-I and II have been simulated in five different moments of time which coincide with the DEXA measurements: postoperative, 6 months, 1, 3 and 5 years, in addition to the healthy femur as the initial reference. For the complete comparative analysis of both stems, all of the possible combinations of bone mass (group I and group II of pacients in two controlled studies for ABG-I and II stems, respectively, prosthetic geometry (ABG-I and ABG-II and stem material (Wrought Titanium or TMZF were simulated. Results and Discussion In both groups of bone mass an increase of stress in the area of the cancellous bone is produced, which coincides with the end of the HA coating, as a consequence of the bottleneck effect which is produced in the transmission of loads, and corresponds to Gruen zones 2 and 6, where no osteopenia can be seen in contrast to zones 1 and 7. Conclusions In this study it is shown that the ABG-II stem is more effective than the ABG-I given that it generates higher tensional values on the bone, due to which proximal bone atrophy diminishes. This biomechanical behaviour with an improved transmission of loads confirmed by means of FE simulation corresponds to the biological findings obtained with

  9. Research on Forging Die Design Ontology

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wenlei; FAN Yushun

    2006-01-01

    Forging die design is heavily dependent on engineers' experiences. But traditional AI technologies can barely provide a standard knowledge representation style for knowledge transferring. This paper introduces ontology into forging die design. 3-layer forging die design ontology is built, which includes Meta-ontology, Domain-ontology and Bottom ontology. Further, by conceptualization, the concepts and their relations are formally addressed by primitives such as Term, Relation and Function etc, which are explicitly expressed by concept tree. Bottom ontology uses Knowledge Item and Prototype to represent and capture general knowledge for knowledge reuse and share. Forging die design ontology building approach is discussed for standard knowledge representation, knowledge mine and knowledge driven CAD design etc. And OWL language is employed for integration among different domain ontologies integration. Finally a locomotive forging die KBE system is presented to demonstrate this approach.

  10. Large head metal-on-metal cementless total hip arthroplasty versus 28mm metal-on-polyethylene cementless total hip arthroplasty: design of a randomized controlled trial

    OpenAIRE

    van Raaij Jos JAM; Bos Nanne; Zijlstra Wierd P

    2008-01-01

    Abstract Background Osteoarthritis of the hip is successfully treated by total hip arthroplasty with metal-on-polyethylene articulation. Polyethylene wear debris can however lead to osteolysis, aseptic loosening and failure of the implant. Large head metal-on-metal total hip arthroplasty may overcome polyethylene wear induced prosthetic failure, but can increase systemic cobalt and chromium ion concentrations. The objective of this study is to compare two cementless total hip arthroplasties: ...

  11. A biodegradable gentamicin-hydroxyapatite-coating for infection prophylaxis in cementless hip prostheses

    NARCIS (Netherlands)

    Neut, D.; Dijkstra, R. J. B.; Thompson, J. I.; Kavanagh, C.; van der Mei, H. C.; Busscher, H. J.

    2015-01-01

    A degradable, poly (lactic-co-glycolic acid) (PLGA), gentamicin-loaded prophylactic coating for hydroxyapatite (HA)-coated cementless hip prostheses is developed with similar antibacterial efficacy as offered by gentamicin-loaded cements for fixing traditional, cemented prostheses in bone. We descri

  12. Effect of rotator cuff dysfunction on the initial mechanical stability of cementless glenoid components

    NARCIS (Netherlands)

    D.R. Suárez (Daniel); E.R. Valstar (Edward); J.C. Linden (Jacqueline); F. van Keulen (Fred); P.M. Rozing (Piet)

    2009-01-01

    textabstractThe functional outcome of shoulder replacement is related to the condition of the rotator cuff. Rotator cuff disease is a common problem in candidates for total shoulder arthroplasty; this study relates the functional status of the rotator cuff to the initial stability of a cementless gl

  13. 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...... 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...

  14. Mechanics and forming theory of liquid metal forging

    Institute of Scientific and Technical Information of China (English)

    罗守靖; 姜巨福; 王迎; 藤东东

    2003-01-01

    On the basis of steel liquid forging and aluminium alloy liquid forging, liquid metal forging was investigated, such as the assembly model, metal plastic flowing, the force-displacement curves, the harmonious equation, calculation of value of altitude deformation and determination of specific pressure of liquid metal forging. On the basis of the theory of metal plastic forming and the characteristics of liquid metal forging, the achievements on the mechanics and forming theory of liquid metal forging were given out by combining the theory and experiments systematically, and an important preparation for establishing liquid metal forging theory was suggested.

  15. Forces at the Main Mechanism of a Railbound Forging Manipulator

    OpenAIRE

    Florian Ion Tiberiu Petrescu; Relly Victoria Virgil Petrescu

    2015-01-01

    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 determine the driving forces of the main mechanism from such manipulator. Forces diagram shows a typical forging manipulator, with the basic motions in operation process: walking, motion of the ton...

  16. International cooperation in cold forging technology

    DEFF Research Database (Denmark)

    Bay, Niels; Lange, K

    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...

  17. Near Net Shape Manufacturing of New Titanium Powders for Industry

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-05-01

    This factsheet describes a research project whose goal is to develop a manufacturing technology to process new titanium powders into fully consolidated near net shape components for industrial applications. This will be achieved using various technologies, including press and sinter, pneumatic isostatic forging (PIF), hot isostatic pressing (HIP), and adiabatic compaction.

  18. Powder Forging of a Motorcycle Connecting Rod

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A motorcycle connecting rod is one of the major moving parts affecting the engine performance. The traditional manufacturing process results in material waste and excessive machining. A new method of hot forging P/M has been proposed and studied experimentally. In order to achieve uniform density, the punch was divided into three parts to consolidate the loose powder. The multistage movement of the three parts of the punch, called synchronous compaction, results in the desired uniform density. Powder flow during consolidation was illustrated and the density distribution of the compacts was measured. A set of forging dies with flash was used to produce densification and deformation of the sintered compact. Then a set of flashless forging dies was designed to obtain the desired shape and dimensions of the connecting rod. The effects of forging temperature and initial compact density on densification were evaluated through hot forging experiments. Based on properties achieved, Fe-C-Cu-Mo was selected as the alloy powder. Through testing and metallographic observation the physical and mechanical properties of the connecting rod produced by the P/M hot forging were found to be superior to those manufactured by the traditional method.

  19. Residual stress in 7449 aluminium alloy forgings

    International Nuclear Information System (INIS)

    The through thickness residual stress distributions within three 120 mm thick rectilinear forgings, made from the high strength aluminium alloy 7449 have been measured using both neutron diffraction and deep hole drilling. Neutron diffraction measurements were made on two instruments, one using a pulsed spallation neutron source, the other a steady state reactor source. Heat treatment of the forgings included a rapid quench into cold water and it was the residual stresses arising from this step that were initially measured. Neutron diffraction measurements indicated large magnitude (>250 MPa) tensile residual stresses in the centre of an as quenched forging, balanced by surface regions stressed in compression (<-200 MPa). Sufficient measurements were made to permit the description of the residual stress distribution using area maps. Two forgings were stress relieved by cold compression immediately after quenching. The degree of plastic strain was either 2.5% or 4%, and was applied by a single application of force in the short transverse direction. Cold compressed forgings were found to have far lower residual stress when compared to the as quenched condition. The amount of cold compression was found to cause an insignificant difference in the final residual stress distribution. The neutron diffraction results are compared to measurements made by deep hole drilling and a new incremental variation of the technique. The deep hole was drilled through the centre of the forgings in the short transverse direction. Multiple neutron diffraction measurements were also made on the extracted cores from the deep hole measurements to assess the variation of the unstrained lattice parameter through the thickness of the forgings.

  20. Primary Stability Recognition of the Newly Designed Cementless Femoral Stem Using Digital Signal Processing

    OpenAIRE

    Mohd Yusof Baharuddin; Sh-Hussain Salleh; Mahyar Hamedi; Ahmad Hafiz Zulkifly; Muhammad Hisyam Lee; Alias Mohd Noor; Harris, Arief Ruhullah A.; Norazman Abdul Majid

    2014-01-01

    Stress shielding and micromotion are two major issues which determine the success of newly designed cementless femoral stems. The correlation of experimental validation with finite element analysis (FEA) is commonly used to evaluate the stress distribution and fixation stability of the stem within the femoral canal. This paper focused on the applications of feature extraction and pattern recognition using support vector machine (SVM) to determine the primary stability of the implant. We measu...

  1. Cementless Hip Arthroplasty in Southern Iran, Midterm Outcome and Comparison of Two Designs

    Directory of Open Access Journals (Sweden)

    Gholam Hossein Shahcheraghi

    2015-09-01

    Full Text Available Background: Cementless hip prosthesis was designed to provide biologic fixation, without the use of cement. The second generation components have shown more reliable bone ingrowths and survival rates. We are reporting a midterm result of two designs of cementless prosthesis in a unique culture with different social habits and expectations. Methods: 52 primary cementless total hip arthroplasty in 42 patients with the mean age of 48.8 years were retrospectively studied. Two groups of prosthesis had been implanted: Harris-Galante II (HGII in 15 and Versys-Trilogy (V-T in 37 hips, both from Zimmer company. The patients were assessed clinically, radiographically and with Harris hip score, SF36, WOMAC, and MACTAR questionnaires, with 65 months (26-136 mean follow-up. Results: All the V-T prostheses had survived well. Eight of HG II were revised by the last follow-up in 19-102 months. All had undergone acetabular revision and 2 combined with femoral revision. Broken tines of HGII cups were seen in 4 radiographs. The 65 months overall survival was 96.2% for femoral and 84.6% for acetabular components. 90% had good or excellent Harris hip scores. The functional scores were poorer in the HG II group. Pain relief and improved walking were the two main patients’ expectations fulfilled in 97.6% and 92.8%, respectively. Conclusions: The outcome of cementless total hip arthroplasty (THA is satisfactory and comparable with the literature based on the results of function and survival of this small comparative group. The use of HGII acetabular component should be abandoned.

  2. A biodegradable gentamicin-hydroxyapatite-coating for infection prophylaxis in cementless hip prostheses

    OpenAIRE

    Neut, D.; RJB Dijkstra; JI Thompson; Kavanagh, C.; HC van der Mei; Busscher HJ

    2015-01-01

    A degradable, poly (lactic-co-glycolic acid) (PLGA), gentamicin-loaded prophylactic coating for hydroxyapatite (HA)-coated cementless hip prostheses is developed with similar antibacterial efficacy as offered by gentamicin-loaded cements for fixing traditional, cemented prostheses in bone. We describe the development pathway, from in vitro investigation of antibiotic release and antibacterial properties of this PLGA-gentamicin-HA-coating in different in vitro models to an evaluation of its ef...

  3. Impact of Temperature on Cooling Structural Variation of Forging Dies

    Science.gov (United States)

    Piesova, Marianna; Czan, Andrej

    2014-12-01

    The article is focused on the issue of die forging in the automotive industry. The cooling effect of temperature on the structure of forged die are under review. In the article, there is elaborated the analysis of theoretical knowledge in the field, focusing on die forging and experimentally proven effect of the cooling rate on the final structure of forged dies made of hypoeutectic carbon steel C56E2.

  4. Dynamic Recrystallization Behavior of Microalloyed Forged Steel

    Institute of Scientific and Technical Information of China (English)

    WANG Jin; CHEN Jun; ZHAO Zhen; RUAN Xue-yu

    2008-01-01

    The dynamic recrystallization behavior of microalloyed forged steel was investigated with a compression test in the temperature range of 1 223--1 473 K and a strain rate of 0. 01--5 s-1. Activation energy was calculated to be 305. 9 kJ/mol by regression analysis. Modeling equations were developed to represent the dynamic reerystalliza-tion volume fraction and grain size. Parameters of the modeling equations were determined as a function of the Zener-Hollomon parameter. The developed modeling equation will be combined with finite element modeling to prediet microstructural change during the hot forging processing.

  5. Bismuth titanate ceramics obtained by hot forging

    International Nuclear Information System (INIS)

    In this work, bismuth titanate samples were obtained from powder calcined at 800 deg C for 24 h through conventional sintering (OF) and hot-forging (HF) methods. The plate-like morphology grains were observed in ceramics obtained in both process. Samples produced by HF showed higher grain orientation, ≅ 90%. (author)

  6. 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. The...

  7. Stainless steel forgings for nuclear chemical plants

    International Nuclear Information System (INIS)

    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)

  8. Computer-based gait analysis of dogs: evaluation of kinetic and kinematic parameters after cemented and cementless total hip replacement.

    Science.gov (United States)

    Drüen, S; Böddeker, J; Meyer-Lindenberg, A; Fehr, M; Nolte, I; Wefstaedt, P

    2012-01-01

    To date it is unclear whether cementless total hip replacement (THR) in dogs is of clinical advantage in comparison to cemented THR with regard to lameness improvement. Thus the aim of this study was to compare objectively the development of the gait pattern after cemented and cementless THR in dogs. For this purpose, 18 adult dogs with hip dysplasia underwent computer-based gait analysis on an instrumented treadmill prior to unilateral THR and then again ten days, four weeks and four months after surgery. Analysed kinetic parameters were symmetry indices (SI) of vertical ground reaction forces (GRF), which included peak vertical forces (PFz), mean vertical forces (MFz), vertical impulse (IFz), and vertical ground reaction forces of the arthroplasty limbs only. Analysed kinematic parameters were range-of-motion and the flexion and extension angles of hip, stifle and hock joints. The symmetry indice for PVF, MFz and IFz decreased to a value less than six in both THR groups four months after surgery, which is defined as not lame. Improvement in lameness of the arthroplasty limbs during the examination period of four months was not significantly different between the cemented and cementless groups. The results suggest that within a short-term observation period of four months after surgery, neither cementless nor cemented THR have a greater advantage with regard to lameness improvement. Additional studies with larger pools of subjects and longer time periods for follow-up examinations are necessary to verify these findings. PMID:22828804

  9. Effects of Materials of Cementless Femoral Stem on the Functional Adaptation of Bone

    Institute of Scientific and Technical Information of China (English)

    He Gong; Wei Wu; Juan Fang; Xin Dong; Meisheng Zhao; Tongtong Guo

    2012-01-01

    The objective of this paper is to identify the effects of materials of cementless femoral stem on the functional adaptive behaviors of bone.The remodeling behaviors of a two-dimensional simplified model of cementless hip prosthesis with stiff stem,flexible 'iso-elastic' stem,one-dimensional Functionally Graded Material (FGM) stem and two-dimensional FGM stem for the period of four years after prosthesis replacement were quantified by incorporating the bone remodeling algorithm with finite element analysis.The distributions of bone density,von Mises stress,and interface shear stress were obtained.The results show that two-dimensional FGM stem may produce more mechanical stimuli and more uniform interface shear stress compared with the stems made of other materials,thus the host bone is well preserved.Accordingly,the two-dimensional FGM stem is an appropriate femoral implant from a biomechanical point of view.The numerical simulation in this paper can provide a quantitative computational paradigm for the changes of bone morphology caused by implants,which can help to improve the design of implant to reduce stress shielding and the risk of bone-prosthesis interface failure.

  10. Influence of Forging on Static Pricing Scheme for Priority Services

    Institute of Scientific and Technical Information of China (English)

    LIU Ji-cheng; SHI Bing-xin; YANG Xue-nan; LI Bo

    2005-01-01

    The influence of ISP's ( internet service provider) forging on static pricing scheme for priority services is analyzed. If ISP is honest, besides the price, after users enter the network market, it can't affect the market; if it forges, it can change its utility. The economical analysis proves that forging is possible, when ISP gains more than its loss, ISP will take the action. In response to forging, users may adapt their traffic allocation vectors to maximize their net benefit. If users will submit more traffic or in higher priority service class, ISP gains from the behavior, if users will submit less traffic or even exits the market, ISP 's utility decrease. The market is completely different from before, forging changes the market. Several examples are presented to illustrate the results. At the same time, how the utility function and the willingness to pay affect forging is discussed.

  11. Enhancement of Aluminum Alloy Forgings through Rapid Billet Heating

    Energy Technology Data Exchange (ETDEWEB)

    Kervick, R.; Blue, C. A.; Kadolkar, P. B.; Ando, T.; Lu, H.; Nakazawa, K.; Mayer, H.; Mochnal, G.

    2006-06-01

    Forging is a manufacturing process in which metal is pressed, pounded or squeezed under great pressure and, often, under high strain rates into high-strength parts known as forgings. The process is typically performed hot by preheating the metal to a desired temperature before it is worked. The forging process can create parts that are stronger than those manufactured by any other metal working process. Forgings are almost always used where reliability and human safety are critical. Forgings are normally component parts contained inside assembled items such airplanes, automobiles, tractors, ships, oil drilling equipment, engines missiles, and all kinds of capital equipment Forgings are stronger than castings and surpass them in predictable strength properties, producing superior strength that is assured, part to part.

  12. A Knowledge base model for complex forging die machining

    CERN Document Server

    Mawussi, Kwamiwi; 10.1016/j.cie.2011.02.016

    2011-01-01

    Recent evolutions on forging process induce more complex shape on forging die. These evolutions, combined with High Speed Machining (HSM) process of forging die lead to important increase in time for machining preparation. In this context, an original approach for generating machining process based on machining knowledge is proposed in this paper. The core of this approach is to decompose a CAD model of complex forging die in geometric features. Technological data and topological relations are aggregated to a geometric feature in order to create machining features. Technological data, such as material, surface roughness and form tolerance are defined during forging process and dies design. These data are used to choose cutting tools and machining strategies. Topological relations define relative positions between the surfaces of the die CAD model. After machining features identification cutting tools and machining strategies currently used in HSM of forging die, are associated to them in order to generate mac...

  13. Computer-aided analysis of the forging process

    OpenAIRE

    Šraml, Matjaž; Stupan, Janez; Potrč, Iztok; Kramberger, Janez

    2012-01-01

    This paper presents computer simulation of the forging process using the finite volume method (FVM). The process of forging is highly non-linear, where both large deformations and continuously changing boundary conditions occur. In most practical cases, the initial billet shape is relatively simple, but the final shape of the end product is often geometrically complex, to the extent that it is commonly obtained using multiple forming stages. Examples of the numerical simulation of the forged ...

  14. 77 FR 23496 - Boundary Revision of Valley Forge National Historical Park

    Science.gov (United States)

    2012-04-19

    ... National Park Service Boundary Revision of Valley Forge National Historical Park AGENCY: National Park... to the boundary of Valley Forge National Historical Park, pursuant to the authority specified below... ``Valley Forge National Historical Park Proposed Boundary Expansion, Montgomery County,...

  15. Numerical modelling of the forging process of rolls for rolling mills

    OpenAIRE

    Charles, J F; Castagne, S.; Zhang, Lihong; Habraken, Anne; Cescotto, Serge

    2000-01-01

    This article presents comparisons of forging processes between two flat tools, between two round tools, and at different forging temperatures. Simulation results help to recover and better understa,d long practice in the forging industry.

  16. Study on the isothermal forging process of MB26 magnesium alloy adaptor

    OpenAIRE

    Xu Wenchen; Yang Chuan; Shaninst Debin; Xu Fuchang; Wang Guan; Guo Bin

    2015-01-01

    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 di...

  17. European Community research on forging of magnesium alloys (MagForge): state of affairs

    NARCIS (Netherlands)

    Sillekens, W.H.; Chevaleyre, F.; Gantar, G.

    2009-01-01

    While the interest in wrought magnesium applications is growing, forging of magnesium alloys in Europe and beyond is still restricted to a few specialized companies that operate for niche markets. Technical matters that relate to this are underdeveloped mechanical properties of available feedstock m

  18. Sinopec,China Gas Forge Strategic Partnership

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Sinopec entered into a strategic cooperation agreement with China Gas Holdings Limited in Beijing on Novemberl, under which both parties will forge a strategic partnership in the natural gas field. Meanwhile, Sinopec will subscribe a total of 210 million new shares at a subscription price of HK$0.61 per share, and the number of shares involved accounts for 11.87% of the total issued capital and 10.61% of the enlarged total capital of China Gas, thus enabling Sinopec to become the second largest shareholder of China Gas.

  19. Forging technology for large nuclear pressure vessel parts

    International Nuclear Information System (INIS)

    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)

  20. 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....

  1. 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.

  2. Numerical Analysis on Rotary Forging Mechanism of a Flange

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A numerical simulation on the rotary forging process of a flange is conducted by three-dimensional rigid-plastic finite element method. The states of stress and strain rate in the workpiece are analyzed and the forging mechanism of the flange is revealed. Moreover, the influence of the die configuration on the material flow is also analyzed.

  3. Utilizing of the metallurgical slag for production of cementless concrete mixtures

    Directory of Open Access Journals (Sweden)

    D. Baricová

    2012-10-01

    Full Text Available In process of pig iron, steel and cast iron production besides main product, also secondary products are formed, that have character of secondary raw materials and industrial wastes. The most abundant secondary product originating in the metallurgical process is furnace slag. Total amount of accured slag, also its chemical, mineralogical, physical – chemical properties and similarity with natural stones predestinate its utilisation in different fields of industry. The contribution deals with production of cementless concrete mixtures, where the main parts were formed by blast furnace granulated slag grinded and different gravel slag from blast furnace, oxygen converter and electric arc furnace. As activators of solidification different kinds of water glass were tested.

  4. Second-Generation Versus First-Generation Cementless Tapered Wedge Femoral Stems.

    Science.gov (United States)

    Pierce, Todd P; Jauregui, Julio J; Kapadia, Bhaveen H; Elmallah, Randa K; Cherian, Jeffrey J; Harwin, Steven F; Mont, Michael A

    2015-09-01

    Clinical outcomes of a new second-generation proximally coated, tapered wedge cementless stem were compared with those of its predecessor regarding (1) all-cause implant survivorship; (2) objective and subjective outcomes; (3) complications; and (4) radiographic features. Patients who underwent a primary total hip arthroplasty with the second-generation stem (68 hips) were compared with those who received the first-generation stem (136 hips) at a mean follow-up of 3.5 years. Although the first-generation stem was designed in the traditional manner, the second-generation stem was shortened to accommodate all surgical approaches and designed using a computed tomography scan-based database to enhance fit. The second-generation stem had survivorship, functional, and subjective outcomes similar to those of the first-generation stem. PMID:26375526

  5. Analysis of cementless implants using interface nonlinear friction--experimental and finite element studies.

    Science.gov (United States)

    Dammak, M; Shirazi-Adl, A; Zukor, D J

    1997-02-01

    Measured interface nonlinear friction properties are used to develop models to study the short-term fixation response of smooth- and porous-surfaced posts, bone screws, and plates fixed with and without posts/screws. Experimental studies are carried out to validate the model predictions and identify the relative role of posts and screws in fixation of a plate on a polyurethane block under symmetric/eccentric axial compression loads. The idealized Coulomb's friction is also used for the sake of comparison. The incorporation of measured nonlinear, rather than the idealized Coulomb, friction is essential to compute realistic results. For plate fixation, the experimental and finite element results show that the screw fixation yields the stiffest response followed by the smooth- and then porous-coated post fixation. For example, under 1000 N eccentric axial compression, the edge of the plate opposite the loaded edge is measured to lift by 1147 +/- 72, 244 +/- 38, or 112 +/- 28 microns, respectively, for the cases with no fixation, with smooth-surfaced posts, or with screws. The corresponding models predict, respectively, values of 1538, 347, or 259 microns and also 556 microns for the plate fixed with porous coated posts. The satisfactory agreement between numerical and experimental results confirms the importance of proper interface modelling for the analysis of posts, screws, and complex fixation systems. This becomes further evident when considering cementless implants in which the bone-implant interface exhibits relatively large displacements as the maximum resistance force is reached. The developed models can be used to investigate the post-operative short-term stability of various cementless implant designs. PMID:9001932

  6. A biodegradable gentamicin-hydroxyapatite-coating for infection prophylaxis in cementless hip prostheses

    Directory of Open Access Journals (Sweden)

    D Neut

    2015-01-01

    Full Text Available A degradable, poly (lactic-co-glycolic acid (PLGA, gentamicin-loaded prophylactic coating for hydroxyapatite (HA-coated cementless hip prostheses is developed with similar antibacterial efficacy as offered by gentamicin-loaded cements for fixing traditional, cemented prostheses in bone. We describe the development pathway, from in vitro investigation of antibiotic release and antibacterial properties of this PLGA-gentamicin-HA-coating in different in vitro models to an evaluation of its efficacy in preventing implant-related infection in rabbits. Bone in-growth in the absence and presence of the coating was investigated in a canine model. The PLGA-gentamicin-HA-coating showed high-burst release, with antibacterial efficacy in agar-assays completely disappearing after 4 days, minimising risk of inducing antibiotic resistance. Gentamicin-sensitive and gentamicin-resistant staphylococci were killed by the antibiotic-loaded coating, in a simulated prosthesis-related interfacial gap. PLGA-gentamicin-HA-coatings prevented growth of bioluminescent staphylococci around a miniature-stem mounted in bacterially contaminated agar, as observed using bio-optical imaging. PLGA-gentamicin-HA-coated pins inserted in bacterially contaminated medullary canals in rabbits caused a statistically significant reduction in infection rates compared to HA-coated pins without gentamicin. Bone ingrowth to PLGA-gentamicin-HA-coated pins, in condylar defects of Beagle dogs was not impaired by the presence of the degradable, gentamicin-loaded coating. In conclusion, the PLGA-gentamicin-HA-coating constitutes an effective strategy for infection prophylaxis in cementless prostheses.

  7. Development and production of nuclear valves. Forging and welding. Pt. 2

    International Nuclear Information System (INIS)

    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)

  8. Initial stability of cementless acetabular cups: press-fit and screw fixation interaction—an in vitro biomechanical study

    OpenAIRE

    Tabata, Tomonori; Kaku, Nobuhiro; Hara, Katsutoshi; Tsumura, Hiroshi

    2014-01-01

    Background Press-fit and screw fixation are important technical factors to achieve initial stability of a cementless acetabular cup for good clinical results of total hip arthroplasty. However, how these factors affect one another in initial cup fixation remains unclear. Therefore, this study aimed to evaluate the mutual influence between press-fit and screw fixation on initial cup stability. Methods Foam bone was subjected to exact hemispherical-shape machining to diameters of 48, 48.5 and 4...

  9. Laser repair hardfacing of titanium alloy turbine

    Directory of Open Access Journals (Sweden)

    A. Klimpel

    2011-12-01

    Full Text Available Purpose: of this paper: work out repair technology of worn abutments of aircraft jet engine blades forged of titanium alloy WT3-1.Design/methodology/approach: The study were based on the analysis of laser HPDL powder surfacing of titanium alloy plates using wide range chemical composition consumables of titanium alloys and mixtures of pure titanium and spherical powder of WC indicated that very hard and highest quality deposits are provided by powder mixture of 40-50%Ti+60-50%WC.Findings: It was found that it is possible to achieve high quality deposits, free of any defects. HPDL technology can be used to repair worn turbine blade.Research limitations/implications: It was found that it is possible to repair the worn areas abutments of blades of zero compression stage of aircraft engine turbine by HPDL laser surfacing with using composite powder mixture of 50%Ti+50%WC as an additional material.Practical implications: The technology can be applied for repair worn abutments of aircraft jet engine blades.Originality/value: Repairing worn abutments of aircraft jet engine blades.

  10. A study on the microstructures and mechanical properties of forged trace-boron-modified Ti–B20 alloy

    International Nuclear Information System (INIS)

    Highlights: • Trace B not only refines grains but improves properties of forged alloys as well. • Ti–B20–0.1B alloys have quick aging response. • Alloy obtained a high strength over 1500 MPa, with its ductility at about 10%. • The precipitation of secondary α phase is sensitive to the temperature of the solution treatment. - Abstract: Microstructure and tensile properties of a high strength metastable beta titanium alloy, Ti–B20–0.1B (wt.%), were studied. The alloy was double melted by vacuum arc melting and subsequently subjected to forging and heat treatment in the α + β phase region. The microstructural characteristics and microstructure–property relationships were investigated by solution treatment at 780 °C/740 °C and subsequent aging from 450 °C to 600 °C. The result showed that the strength of forged alloy was improved by trace boron. The strength of the alloy, which was processed by solution treatment at 780 °C and subsequent aging, was higher than that at 740 °C. Whereas, the ductility, after alloy being solution treated at high temperature, was lower than that at low temperature. Secondary α phase was precipitated incompletely. And precipitate free zone was found in the microstructure after alloy being solution treated at 740 °C followed by short-time or low-temperature aging. Secondary α phase grew with the increase of the aging temperature and aging time

  11. Total hip arthroplasty in patients with avascular necrosis of the hip. Follow-up observations on cementless and cemented operations.

    Science.gov (United States)

    Katz, R L; Bourne, R B; Rorabeck, C H; McGee, H

    1992-08-01

    Thirty-one patients with avascular necrosis of the hip were treated by 34 total hip arthroplasties (THAs). All patients were observed prospectively with a minimum two-year follow-up evaluation (average, 46 months; range, 24-84 months). Twenty had cemented arthroplasties using contemporary cementing techniques. This included insertion of a medullary plug, cleansing of the canal with a medullary brush, pulsatile lavage irrigation, and insertion of the cement with a cement gun. In 14 hips, a cementless prosthesis was used. Patients were rated using a modified Harris hip score. Sequential postoperative roentgenograms were analyzed in each patient. The overall Harris hip score ratings were 88 in the cemented and 84 in the noncemented groups. Mechanical failure with loosening of the femoral component occurred in one patient who developed deep sepsis. Significant thigh pain occurred in four patients in the noncemented group. Previous studies in the literature have generally reported unfavorable results in patients with avascular necrosis of the hip treated with THA. Using cementless and cemented fixation with contemporary cementing techniques, improved results can be expected. A high incidence of thigh pain (29%) in the cementless group remains a problem. PMID:1499201

  12. Migration pattern of cementless press fit cups in the presence of stabilizing screws in total hip arthroplasty

    Directory of Open Access Journals (Sweden)

    Zilkens C

    2011-03-01

    Full Text Available Abstract The aim of this study was to evaluate the initial acetabular implant stability and late acetabular implant migration in press fit cups combined with screw fixation of the acetabular component in order to answer the question whether screws are necessary for the fixation of the acetabular component in cementless primary total hip arthroplasty. One hundred and seven hips were available for follow-up after primary THA using a cementless, porous-coated acetabular component. A total of 631 standardized radiographs were analyzed digitally by the "single-film-x-ray-analysis" method (EBRA. One hundred 'and one (94.4% acetabular components did not show significant migration of more than 1 mm. Six (5.6% implants showed migration of more than 1 mm. Statistical analysis did not reveal preoperative patterns that would identify predictors for future migration. Our findings suggest that the use of screw fixation for cementless porous- coated acetabular components for primary THA does not prevent cup migration.

  13. Migration pattern of cementless press fit cups in the presence of stabilizing screws in total hip arthroplasty.

    Science.gov (United States)

    Zilkens, C; Djalali, S; Bittersohl, B; Kälicke, T; Kraft, C N; Krauspe, R; Jäger, Marcus

    2011-03-28

    The aim of this study was to evaluate the initial acetabular implant stability and late acetabular implant migration in press fit cups combined with screw fixation of the acetabular component in order to answer the question whether screws are necessary for the fixation of the acetabular component in cementless primary total hip arthroplasty. One hundred and seven hips were available for follow-up after primary THA using a cementless, porous-coated acetabular component. A total of 631 standardized radiographs were analyzed digitally by the "single-film-x-ray-analysis" method (EBRA). One hundred and one (94.4 %) acetabular components did not show significant migration of more than 1 mm. Six (5.6%) implants showed migration of more than 1 mm. Statistical analysis did not reveal preoperative patterns that would identify predictors for future migration. Our findings suggest that the use of screw fixation for cementless porous-coated acetabular components for primary THA does not prevent cup migration. PMID:21486725

  14. Integration of Heat Treatment in precision forging of gear wheels

    International Nuclear Information System (INIS)

    The conventional process chain for the production of gear wheels demands many manufacturing steps. Typically this process chain consists of cutting, heating, forging and deburring. Subsequently, the teeth and the bores of the gears are shaped in a machining process such as milling, slotting and broaching. Afterwards, a heat treatment by case hardening is applied and the gears are finally finished by grinding by grinding. This process chain is often disrupted by storage and transports. Precision forging can significantly reduce this process chain because deburring and machining steps become unnecessary. Additional advantages can be gained if the heat of the precision forging process is used for an integrated heat treatment. Moreover, specific component characteristics can be reached by integrating the heat treatment in connection with an adapted process technology. Hot formed parts are directly hardened by using the forging heat. A new solution for a homogeneous cooling consisting of a two-phase nozzle array will be introduced. The application of this technique allows the hardening of particular component regions according to typical strain profiles of this component. Besides, demands on material properties, an even allowance after the precision forging process has to be maintained. The allowance after the forging process depends on varying alloys and the geometry of the part as well as the forging temperature and related heat loss. The tool must therefore be corrected and adapted accordingly. The new approach for the presented process chain with new tool concepts and an integrated heat treatment using the forging heat will solve many problems. Moreover, dramatic change in the process management is necessary. But on the other hand it offers great potential for cost reduction. Particularly, high-duty automotive components offer a wide application field for the precision forging technology. Advantages like shortened production cycles achieved by eliminating machining

  15. 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.

  16. Surface Defects on Forged Nut of Stainless Steel

    Directory of Open Access Journals (Sweden)

    Sasa Tomonori

    2016-01-01

    Full Text Available Surface quality of nuts used in gas pipe joints is an important issue because the surface state affects the fatigue characteristics. Surface defects of nuts produced by warm forging from a stainless steel are observed and the cause of defect generation is discussed based on the numerical results of FEM simulation. It is revealed that there exists the lap defect on the drawn wire surface with an opened end and the surface defects on the forged nut are generated by the tensile stress during forging since there exists a moment at almost the whole area of the billet surface that a tensile stress over 200MPa is generated during nut forging.

  17. Valley Forge National Historical Park Tract and Boundary Data

    Data.gov (United States)

    National Park Service, Department of the Interior — This is an ESRI polygon shapefile of tracts for Valley Forge NHP (VAFO). Tracts shown on inset maps A, B, and C were spatially adjusted (i.e., rubbersheeted) to...

  18. Engineering of forged products of microalloyed constructional steels

    OpenAIRE

    J. Adamczyk; M. Opiela

    2006-01-01

    Purpose: Effect of the thermo-mechanical treatment conditions on the structure and mechanical properties of the forged elements of constructional C-Mn steels with Ti, V, B and N microadditions.Design/methodology/approach: Metallography, electron microscopy, tensile test, hardness measurements, hardenability calculations, Charpy-V tests have been used.Findings: The thermo-mechanical treatment allows to obtain the fine-grained austenite structure during hot plastic deformation, and gives forged...

  19. Biomechanical evaluation of adjunctive cerclage wire fixation for the prevention of periprosthetic femur fractures using cementless press-fit total hip replacement.

    Science.gov (United States)

    Christopher, Scott A; Kim, Stanley E; Roe, Simon; Pozzi, Antonio

    2016-08-01

    Periprosthetic femoral fractures are a common complication associated with cementless press-fit total hip arthroplasty. The use of prophylactic cerclage wire fixation has been advocated to reduce this complication. The objective of this study was to evaluate whether a double loop cerclage wire, used as adjunctive fixation, increased the peak torsional load to failure in femora implanted with press-fit cementless stems. Peak torsional load to failure was compared between femora without adjunctive fixation and femora receiving a 1 mm double loop cerclage wire placed proximally to the lesser trochanter. Femora treated with adjunctive cerclage wire fixation failed at 20% greater peak torque (P = 0.0001). In conclusion, a double loop cerclage wire may aid in the prevention of periprosthetic fractures associated with press-fit cementless femoral stems. PMID:27387718

  20. New titanium and titanium/hydroxyapatite coatings on ultra-high-molecular-weight polyethylene-in vitro osteoblastic performance

    International Nuclear Information System (INIS)

    The development of optimized hip joint materials is one of the most challenging opportunities in prosthetic technologies. In current approaches, ultra-high-molecular-weight polyethylene (UHMWPE) has been a favorite material for the acetabular component and, regarding the cementless technique, several coating options may be considered to contain and stabilize bearing surfaces and establish an improved interface with bone. In this work, newly developed constructs of UHMWPE coated with either commercially pure titanium (cpTi-UHMWPE), by DC magnetron sputtering, or with commercially pure titanium and hydroxyapatite (cpTi/HA-UHMWPE), by DC/RF magnetron co-sputtering, have been prepared and biologically characterized with human bone marrow-derived osteoblastic cultures. The cpTi-UHMWPE samples allowed a high cell growth and the expression of the complete osteoblastic phenotype, with high alkaline phosphatase activity, expression of osteogenic-associated genes and evident cell-mediated mineralization of the extracellular matrix. In comparison, the cpTi/HA-UHMWPE samples reported lower cell proliferation but earlier cell-mediated matrix mineralization. Accordingly, these newly developed systems may be suitable candidates to improve the osteointegration process in arthroplastic devices; nevertheless, further biological evaluation should be conducted.

  1. New titanium and titanium/hydroxyapatite coatings on ultra-high-molecular-weight polyethylene-in vitro osteoblastic performance

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M A; Lopes, M A; Santos, J D; Fernandes, M H [Department of Metallurgical and Materials Engineering, Materials Section-Faculty of Engineering, University of Porto (Portugal); Gomes, P S [Laboratory of Pharmacology and Cellular Biocompatibility-Faculty of Dental Medicine, University of Porto (Portugal); Vila, M; Silva, R F, E-mail: mhfernandes@fmd.up.p [Department of Ceramics and Glass Engineering, University of Aveiro, CICECO (Portugal)

    2010-06-15

    The development of optimized hip joint materials is one of the most challenging opportunities in prosthetic technologies. In current approaches, ultra-high-molecular-weight polyethylene (UHMWPE) has been a favorite material for the acetabular component and, regarding the cementless technique, several coating options may be considered to contain and stabilize bearing surfaces and establish an improved interface with bone. In this work, newly developed constructs of UHMWPE coated with either commercially pure titanium (cpTi-UHMWPE), by DC magnetron sputtering, or with commercially pure titanium and hydroxyapatite (cpTi/HA-UHMWPE), by DC/RF magnetron co-sputtering, have been prepared and biologically characterized with human bone marrow-derived osteoblastic cultures. The cpTi-UHMWPE samples allowed a high cell growth and the expression of the complete osteoblastic phenotype, with high alkaline phosphatase activity, expression of osteogenic-associated genes and evident cell-mediated mineralization of the extracellular matrix. In comparison, the cpTi/HA-UHMWPE samples reported lower cell proliferation but earlier cell-mediated matrix mineralization. Accordingly, these newly developed systems may be suitable candidates to improve the osteointegration process in arthroplastic devices; nevertheless, further biological evaluation should be conducted.

  2. Primary stability recognition of the newly designed cementless femoral stem using digital signal processing.

    Science.gov (United States)

    Baharuddin, Mohd Yusof; Salleh, Sh-Hussain; Hamedi, Mahyar; Zulkifly, Ahmad Hafiz; Lee, Muhammad Hisyam; Mohd Noor, Alias; Harris, Arief Ruhullah A; Abdul Majid, Norazman

    2014-01-01

    Stress shielding and micromotion are two major issues which determine the success of newly designed cementless femoral stems. The correlation of experimental validation with finite element analysis (FEA) is commonly used to evaluate the stress distribution and fixation stability of the stem within the femoral canal. This paper focused on the applications of feature extraction and pattern recognition using support vector machine (SVM) to determine the primary stability of the implant. We measured strain with triaxial rosette at the metaphyseal region and micromotion with linear variable direct transducer proximally and distally using composite femora. The root mean squares technique is used to feed the classifier which provides maximum likelihood estimation of amplitude, and radial basis function is used as the kernel parameter which mapped the datasets into separable hyperplanes. The results showed 100% pattern recognition accuracy using SVM for both strain and micromotion. This indicates that DSP could be applied in determining the femoral stem primary stability with high pattern recognition accuracy in biomechanical testing. PMID:24800230

  3. Primary Stability Recognition of the Newly Designed Cementless Femoral Stem Using Digital Signal Processing

    Directory of Open Access Journals (Sweden)

    Mohd Yusof Baharuddin

    2014-01-01

    Full Text Available Stress shielding and micromotion are two major issues which determine the success of newly designed cementless femoral stems. The correlation of experimental validation with finite element analysis (FEA is commonly used to evaluate the stress distribution and fixation stability of the stem within the femoral canal. This paper focused on the applications of feature extraction and pattern recognition using support vector machine (SVM to determine the primary stability of the implant. We measured strain with triaxial rosette at the metaphyseal region and micromotion with linear variable direct transducer proximally and distally using composite femora. The root mean squares technique is used to feed the classifier which provides maximum likelihood estimation of amplitude, and radial basis function is used as the kernel parameter which mapped the datasets into separable hyperplanes. The results showed 100% pattern recognition accuracy using SVM for both strain and micromotion. This indicates that DSP could be applied in determining the femoral stem primary stability with high pattern recognition accuracy in biomechanical testing.

  4. Primary Stability Recognition of the Newly Designed Cementless Femoral Stem Using Digital Signal Processing

    Science.gov (United States)

    Salleh, Sh-Hussain; Hamedi, Mahyar; Zulkifly, Ahmad Hafiz; Lee, Muhammad Hisyam; Mohd Noor, Alias; Harris, Arief Ruhullah A.; Abdul Majid, Norazman

    2014-01-01

    Stress shielding and micromotion are two major issues which determine the success of newly designed cementless femoral stems. The correlation of experimental validation with finite element analysis (FEA) is commonly used to evaluate the stress distribution and fixation stability of the stem within the femoral canal. This paper focused on the applications of feature extraction and pattern recognition using support vector machine (SVM) to determine the primary stability of the implant. We measured strain with triaxial rosette at the metaphyseal region and micromotion with linear variable direct transducer proximally and distally using composite femora. The root mean squares technique is used to feed the classifier which provides maximum likelihood estimation of amplitude, and radial basis function is used as the kernel parameter which mapped the datasets into separable hyperplanes. The results showed 100% pattern recognition accuracy using SVM for both strain and micromotion. This indicates that DSP could be applied in determining the femoral stem primary stability with high pattern recognition accuracy in biomechanical testing. PMID:24800230

  5. Failure of Polyethylene Inlays in Cementless Total Hip Arthroplasty: A Retrieval Analysis

    Directory of Open Access Journals (Sweden)

    Ulrike Mueller

    2016-01-01

    Full Text Available A retrieval analysis has been performed on 50 polyethylene inlays of cementless screw ring implants (Mecring, Mecron, Berlin, Germany to investigate the failure mechanism of this specific open cup hip arthroplasty design that has shown a high clinical failure rate. Design-specific damage modes like rim creep, collar fatigue, and backside wear were assessed. Furthermore, the inlays were measured using a CMM to determine deformation. In 90% backside wear was observed and collar fatigue occurred in 68% of the cases. Rim creep was present in 38% of the polyethylene inlays. In 90% of the cases the cup opening diameter was 32.1 mm or less and 46% had a diameter less than 32 mm. It seems that creep and deformation of the polyethylene leads to a reduced diameter at the cup opening and consequently decreased clearance. To avoid this type of failure, polyethylene inlays should be supported at the back by the cup to reduce the risk of ongoing creep deformation.

  6. A multicenter approach evaluating the impact of vitamin E-blended polyethylene in cementless total hip replacement

    Directory of Open Access Journals (Sweden)

    Marcus Jäger

    2014-04-01

    Full Text Available Since polyethylene is one of the most frequently used biomaterials as a liner in total hip arthroplasty, strong efforts have been made to improve design and material properties over the last 50 years. Antioxidants seems to be a promising alternative to further increase durability and reduce polyethylene wear in long term. As of yet, only in vitro results are available. While they are promising, there is yet no clinical evidence that the new material shows these advantages in vivo. To answer the question if vitamin-E enhanced ultra-high molecular weight polyethylene (UHMWPE is able to improve long-term survivorship of cementless total hip arthroplasty we initiated a randomized long-term multicenter trial. Designed as a superiority study, the oxidation index assessed in retrieval analyses of explanted liners was chosen as primary parameter. Radiographic results (wear rate, osteolysis, radiolucency and functional outcome (Harris Hip Scores, University of California-Los Angeles, Hip Disability and Osteoarthritis Outcome Score, Visual Analogue Scale will serve as secondary parameters. Patients with the indication for a cementless total hip arthroplasty will be asked to participate in the study and will be randomized to either receive a standard hip replacement with a highly cross-linked UHMWPE-X liner or a highly cross-linked vitamin-E supplemented UHMWPE-XE liner. The follow-up will be 15 years, with evaluation after 5, 10 and 15 years. The controlled randomized study has been designed to determine if Vitamin-E supplemented highly cross-linked polyethylene liners are superior to standard XLPE liners in cementless total hip arthroplasty. While several studies have been started to evaluate the influence of vitamin-E, most of them evaluate wear rates and functional results. The approach used for this multicenter study, to analyze the oxidation status of retrieved implants, should make it possible to directly evaluate the ageing process and development

  7. Total hip arthroplasty with cementless cups and femoral head autografts for patients with hip dysplasia and osteoarthritis

    Institute of Scientific and Technical Information of China (English)

    吴立东; 金礼斌; 严世贵; 杨泉森; 戴雪松; 王祥华

    2004-01-01

    Objective:To evaluate the outcome of total hip arthroplasty (THA) with cementless cups and femoral head autografts for patients with hip dysplasia and osteoarthritis.Methods: Between 1995 and 2002, we implanted 23cementless cups and femoral head autografts in 20 patients with hip dysplasia and osteoarthritis. In this study, a retrospective study was made on 21 hips in 20 patients (18females and 2 males, aged 50 years on an average) with developmental hip dysplasia treated by THA with acementless cup and femoral head autograft. The acetabular cup was placed at the level of the true acetabuinm and all the patients required autogenous femoral head grafts due to acetabular deficiency. The average rate of the acetabular cup covered by the femoral head autograft was 31%(ranging from 10% to 45%). Eight hips had less than 25%cup coverage and thirteen between 25% and 50%. The average follow-up period was 4.7 years (range, 1-8 years).The replacing outcome was evaluated by modified Harris hip score. Preoperative and follow-up radiographs were made.Results: All the autografts were united to the host bones. No autograft was collapsed or no component from the hip was loosed in all the patients. According to the modified Harris hip score, the average hip score increased from 46 before operation to 89 at the final review. Before operation, the leg-length discrepancy was greater than 2 cm in all the patients except one with bilateral hip dysplasia.After operation, only 2 out of 20 patients had a leg-length discrepancy greater than 1 cm. Three hips showed minor bone resorption in the lateral portion of the graft, which did not support the cup. Three hips developed Grade 1Brooker heterotopic ossification and one developed Grade 2.Conclusions: THA with a cementless cup and a femoral head autograft for patients with osteoarthritis resulted from hip dysplasia can result in favorable outcomes. This method can provide reliable acetabular fixation and restore the acetabular bone stock in

  8. Refinement of steel microstructure by free-forging

    Directory of Open Access Journals (Sweden)

    D. Jandová

    2006-04-01

    Full Text Available Purpose: Refinement of austenitic steel and low alloyed C-Mn-Si-Nb steel microstructure by free-forging.Design/methodology/approach: In this study severe hot deformation was applied on low alloyed 0.2C-1.5Mn-2Si-0.05Nb steel and austenitic 0.07C-18Cr-2Mn.-10Ni steel. Steels were processed in a full-hydraulic press. Different temperatures of preheating, dwells and strain levels were applied. Microstructure was characterised using optical metallography, scanning and transmission electron microscopy.Findings: After optimization of processing fine grained structures with convenient phase composition were obtained. Multiple free-forging followed by recrystallization annealing was successfully used for refinement of austenitic Cr-Ni steel and improvement of mechanical properties. While free-forging of low alloyed C-Mn-Si-Nb steel still has not satisfied expected increase of strength and ductility.Research limitations/implications: Free-forging usually results in formation of very heterogeneous structures. In submitted study relatively fine grained and uniform structures were obtained. Grain size below a few micrometers can not be probably achieved using above mentioned technology.Originality/value: Obtained results can be used for development of forging technology in service conditions.

  9. Engineering of forged products of microalloyed constructional steels

    Directory of Open Access Journals (Sweden)

    J. Adamczyk

    2006-02-01

    Full Text Available Purpose: Effect of the thermo-mechanical treatment conditions on the structure and mechanical properties of the forged elements of constructional C-Mn steels with Ti, V, B and N microadditions.Design/methodology/approach: Metallography, electron microscopy, tensile test, hardness measurements, hardenability calculations, Charpy-V tests have been used.Findings: The thermo-mechanical treatment allows to obtain the fine-grained austenite structure during hot plastic deformation, and gives forged elements obtaining: yield point Rp0,2 over 690 MPa, UTS over 770 MPa, hardness 220 up to 250 HB and breaking energy KV over 180J after high tempering.Research limitations/implications: It is predicted TEM investigations on structure of the forged elements after thermo-mechanical treatment.Practical implications: Investigations carried out showed full usability of micro-alloyed steels for producing forged machine parts with the high strength and cracking resistance, using the energy-saving thermo-mechanical treatment method.Originality/value: Production conditions of energy-saving thermo-mechanical treatment of forged elements of HSLA constructional steels – with the diversified hardenability, were presented.

  10. HepForge A lightweight development environment for HEP software

    CERN Document Server

    Buckley, A; Nurse, E; Stirling, W J; Waugh, B; Whalley, M R

    2006-01-01

    Setting up the infrastructure to manage a software project can become a task as significant writing the software itself. A variety of useful open source tools are available, such as Web-based viewers for version control systems, "wikis" for collaborative discussions and bug-tracking systems, but their use in high-energy physics, outside large collaborations, is insubstantial. Understandably, physicists would rather do physics than configure project management tools. We introduce the CEDAR HepForge system, which provides a lightweight development environment for HEP software. Services available as part of HepForge include the above-mentioned tools as well as mailing lists, shell accounts, archiving of releases and low-maintenance Web space. HepForge also exists to promote best-practice software development methods and to provide a central repository for re-usable HEP software and phenomenology codes.

  11. 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...... conversion coatings are based on zinc phosphates but different requirements to the coating properties have to be met in different cold forging operations. This is obtained by adopting different oxidants leading to different composition, layer thickness and morphology of the conversion coatings. Concerning...... aluminium unalloyed and softer alloys like the AA 1000, 3000 and 6000 series can be cold forged with either grease, oil or zinc stearate whereas the harder alloys from series AA 2000, 5000 and 7000 require a conversion coating to carry the lubricant. Three different types of conversion coating are described...

  12. 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....... The results show, that friction is strongly influenced by normal pressure and tool/work piece interface temperature, whereas the other process parameters investigated show minor influence on friction. Based on the experimental results a mathematical model has been established for friction as a...... function 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....

  13. Microstructure and mechanical properties of cementless construction materials from thermal engineering wastes

    International Nuclear Information System (INIS)

    In order to solve environment problems of ceramics industry new compositions of materials were developed from three types of porcelain production tails – fired wastes (FW), unfired wastes (UW) and wastewater treatment plant sludge (WTPS) – as the main raw materials of new compositions of cementless building materials. The binder material used here was lime production waste (LPW), i.e., incompletely burned lime. The uniaxial compressive strength of the new materials containing 15 wt% of LPW at one year of age increased up to 14.2 MPa and the materials with 5% LPW content increased up to 8.6 MPa, exceeding the specifications of Brazilian standards for hollow concrete blocks. The water absorption (WA) coefficient of different compositions at the age of 28 days ranged from 17.9 to 24.6%, but this does not affect the values of the water resistance coefficient (0.71–0.85). X-ray diffraction and scanning electron microscopy analyses indicated that the strength of the new materials increases due to the synthesis of amorphous and crystalline compounds. The feasibility of the new materials based on the use of four types of industrial wastes for the production of new building materials with high mechanical properties, which meet the requirements of national standards. - Highlights: • New construction material from three types of Porcelain industry wastes. • Lime production waste was used as binder material. • Uniaxial resistance strength at the age of one year reached 14 MPa. • Structure formation processes were determined by XRD, SEM and EDS methods. • Utilization of industrial wastes has high economical and environment efficiency

  14. The dimensional accuracy of preparation of femoral cavity in cementless total hip arthroplasty

    Institute of Scientific and Technical Information of China (English)

    吴立东; HAHNEH.J.; HASSENPFLUGJ.

    2004-01-01

    Objective: To observe the accuracy of femoral preparation and the position of the cementless prosthesis in femoral cavity, and to compare the results between the computer-assisted surgical group (CASPAR) and the conventional group. Methods: Ten femoral components were implanted either manually or by CASPAR in cadaver femurs. The specimens were cut to 3mm thick slices. Microradiograms of every slice were sent to a computer for analysis with special software (IDL). The gaps and the medullary cavities between component and bone, the direct bone contact area of the implant surface, the gap width and the percentage of gap and bone contact area were measured in every slice. Results: In the proximal implant coated with HA of the CASPAR group, the average percentage of bone contact reached 93.2% (ranging from 87.6% to 99.7%); the average gap percentage was 2.9% (ranging from 0.3% to 7.8%); the maximum gap width was 0.81mm and the average gap width was only 0.20mm. While in the conventional group, the average percentage of bone contact reached 60.1% (ranging from 49.2% to 70.4%); the average gap percentage was 32.8% (ranging from 25.1% to 39.9%); the maximum gap width was 2.97mm and the average gap width was 0.77mm. The average gap around the implant in the CASPAR group was only 9% of that in the manual group; the maximum and average gap widths were only about 26% of those in the manual group. On the other hand, the CASPAR group showed 33% higher bone contact than the manual group. Conclusion: With the use of robotics-assisted system, significant progress can be achieved for femoral preparation in total hip arthroplasty.

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

    International Nuclear Information System (INIS)

    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

  16. Titanium and titanium alloys fundamentals and applications

    CERN Document Server

    Peters, Manfred

    2003-01-01

    This handbook is an excellent reference for materials scientists and engineers needing to gain more knowledge about these engineering materials. Following introductory chapters on the fundamental materials properties of titanium, readers will find comprehensive descriptions of the development, processing and properties of modern titanium alloys. There then follows detailed discussion of the applications of titanium and its alloys in aerospace, medicine, energy and automotive technology.

  17. Treatment of Hip Dysplasia in a Dog after a Failed Triple Pelvic Osteotomy with a Zurich Cementless Total Hip Replacement

    Directory of Open Access Journals (Sweden)

    SY Heo and H.B Lee*

    2013-07-01

    Full Text Available An Alaskan Malamute (2-year-old, castrated male, 41kg was referred with bilateral hind limb lameness. The dog had a history of a bilateral triple pelvic osteotomy (TPO to correct hip dysplasia one year previously, a surgery that was unsuccessful. On physical examination, pain and crepitus were noted in both hip joints. There was hip joint subluxation and mild degenerative changes bilaterally seen by radiograph. A Zurich cementless total hip replacement (ZCTHR was planned for the right hind limb. After a craniolateral approach, an acetabular cup and a cementless femoral stem were implanted. The femoral head was placed in the femoral stem, and the prosthetic joint was then reduced. At a 9 month postoperative checkup, there was no pain on palpation or manipulation of the right pelvic limb, and the range of motion was within normal limits. On radiological examination, there was no implant loosening. The ZCTHR can thus be applied in a failed TPO patient as a revision surgery.

  18. Enhancement of mechanical properties of alloy steels on hot forging

    International Nuclear Information System (INIS)

    The paper present the results of an investigation into the effects of the basic parameters of high-temperature thermomechanical treatment (HTTMT) under hot forging. It is shown that forging in open dies of 45Kh, 20Kh13 and 08Kh18N10T steel blanks following the established HTTMT modes improves the ultimate strength by 46, 56 and 2% respectively, and yield limit - by 65, 66 and 14%, as compared with their production in compliance with factory modes, preserving the level of ductility and impact strength

  19. 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 is...

  20. 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)

    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

  1. 77 FR 14445 - Application for a License To Export Steel Forging

    Science.gov (United States)

    2012-03-09

    ... FR 49139 (Aug. 28, 2007). Information about filing electronically is available on the NRC's public... COMMISSION Application for a License To Export Steel Forging Pursuant to 10 CFR 110.70(b) ``Public Notice of... Spain. December 15, 2011 head steel head steel February 7, 2012 forging. forging will be XR175...

  2. Modelling of the radial forging process of a hollow billet with the mandrel on the lever radial forging machine

    Science.gov (United States)

    Karamyshev, A. P.; Nekrasov, I. I.; Pugin, A. I.; Fedulov, A. A.

    2016-04-01

    The finite-element method (FEM) has been used in scientific research of forming technological process modelling. Among the others, the process of the multistage radial forging of hollow billets has been modelled. The model includes both the thermal problem, concerning preliminary heating of the billet taking into account thermal expansion, and the deformation problem, when the billet is forged in a special machine. The latter part of the model describes such features of the process as die calibration, die movement, initial die temperature, friction conditions, etc. The results obtained can be used to define the necessary process parameters and die calibration.

  3. 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 to...

  4. Electronic Portfolios in Teacher Education: Forging a Middle Ground

    Science.gov (United States)

    Strudler, Neal; Wetzel, Keith

    2012-01-01

    At a time when implementation of electronic portfolios (EPs) is expanding, the issues of clarifying their purposes continue to plague teacher education programs. Are student-centered uses of EPs compatible with program assessment and accreditation efforts? Is this an either/or situation, or can a productive middle ground be forged? This article…

  5. 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…

  6. Hot Forging of Nitrogen Alloyed Duplex Stainless Steels

    Institute of Scientific and Technical Information of China (English)

    P.Chandramohan; S.S. Mohamed Nazirudeen; S.S. Ramakrishnan

    2007-01-01

    Duplex stainless steels are gaining global importance because of the need for a high strength corrosion resistant material. Three compositions of this group were selected with three different nitrogen contents viz, 0.15 wt pct (alloy 1), 0.23 wt pct (alloy 2) and 0.32 wt pct (alloy 3). The steels were melted in a high frequency induction furnace and hot forged to various reductions from 16% to 62%. In this work, the effect of hot forging on the ferrite content, hardness, yield strength, impact strength and grain orientation (texture) were studied. Fracture analysis on all the forged specimens using SEM reveals that a size reduction of 48% results in maximum ductility and impact strength as well as minimal ferrite content and grain size. Thus the mechanical properties are found to have a direct correlation to ferrite content and grain size. The highest impact strength was observed in specimens with the smallest grain size, which was observed in specimens forged to 48% reduction in size.

  7. HEAT TREATMENT BEHAVIOR OF CAN-FORGED TITANIUM ALUMINIDE ALLOY IN (α+γ) REGION

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Titaniumaluminidebasedaloyhasbeencon-sideredasapromisinghightemperaturematerial,especialyforrotarycomponents.Havingbeenstudie...

  8. Forging tools modification with graphene-like solid lubricant nanoparticles

    Directory of Open Access Journals (Sweden)

    V. Leshchynsky

    2010-11-01

    Full Text Available Purpose: Working conditions of forging tools have become severer with the years. To increase their wear andheat resistance the surface of the tool is coated by CVD/PVD methods. Relatively high friction coefficientof coatings results in high friction losses and low durability of coating films due to high shear stress at tool–workpiece interface. That is why improved self-lubricating system should be developed. Combination of moderncoatings (nanostructured, nanolayers, nanocomposites, etc. with self-lubricating tool design and application ofsolid lubricant MoS2 and WS2 graphene-like nanoparticles is very promising and effective way to solve existingforging tool problems.Design/methodology/approach: Laser micro-machining technology was applied to fabricate the network ofmicro-channels which serve like reservoirs for encapsulation of solid lubricant nanoparticles into tool body.Wide ranges of tribological tests on T-10 ball-on-disc tester were carried out to define the optimal geometryand network configuration of micro-channels ensuring generation of a lubricious transfer film at the tribologicalcontact.Findings: As a result, increased tool durability and high forging precision could be reached. Analysis of failuremechanisms for different forging tools were carried out. It was found that one of the important reasons of toolwear is a high friction coefficient between treated material and the tool. Graphene-like nanoparticles of MoS2solid lubricant were produced by Rolling Cleavage Technology. Paper consist SEM, TEM and AFM analysis ofapplied coatings and solid lubricant particles.Research limitations/implications: The continuous supply to a sliding area of nanoparticles will be for thefirst time applied to decrease high shear stress at an interface between forging tool and treated material.Thenext research step will be the transfer of the developed methods of self-lubrication from samples to real coldforging tools.Originality/value: Analysis of

  9. Evaluation of the hot forging adjustment to the manufacture of forged parts: criteria of viability and optimization

    International Nuclear Information System (INIS)

    The design of industrial parts is a clear example of integrative effort that, with a focus of several disciplines, requires a detailed analysis of the different scientific and technological knowledge implied in its conception and development. Inside this performance context, the present work approaches the problem of the project of hot forging parts, proposing the use of criteria of viability and optimization that, based in technical and economical considerations, allow to valuate the adjusting degree of various alternative to the forge process, facilitating with it the selection of the most appropriate. Fixed these bases and with object of shortening times of answer analysis in an application corresponding to parts with revolution symmetry, a computerized system has been introduced that, taking as started data the design of the part, geometrically simulates the forge process, allowing to calculate the adaptation coefficients in those morphologies that are possible according to the criteria of viability criteria. This system also provides a graphic representation of machined part, the forged part and the finished stamp. (Author) 22 refs

  10. Titanium condenser tubes

    International Nuclear Information System (INIS)

    The corrosion resistance of titanium in sea water is extremely excellent, but titanium tubes are expensive, and the copper alloy tubes resistant in polluted sea water were developed, therefore they were not used practically. In 1970, ammonia attack was found on the copper alloy tubes in the air-cooled portion of condensers, and titanium tubes have been used as the countermeasure. As the result of the use, the galvanic attack an copper alloy tube plates with titanium tubes as cathode and the hydrogen absorption at titanium tube ends owing to excess electrolytic protection were observed, but the corrosion resistance of titanium tubes was perfect. These problems can be controlled by the application of proper electrolytic protection. The condensers with all titanium tubes adopted recently in USA are intended to realize perfectly no-leak condensers as the countermeasure to the corrosion in steam generators of PWR plants. Regarding large condensers of nowadays, three problems are pointed out, namely the vibration of condenser tubes, the method of joining tubes and tube plates, and the tubes of no coolant leak. These three problems in case of titanium tubes were studied, and the problem of the fouling of tubes was also examined. The intervals of supporting plates for titanium tubes should be narrowed. The joining of titanium tubes and titanium tube plates by welding is feasible and promising. The cleaning with sponge balls is effective to control fouling. (Kako, I.)

  11. Evaluation of Tensile Properties and their Correlation with Microstructural Characteristics of a Closed Die Forging of Iso-symmetrical Aerospace Grade Ti-6Al-4V Alloy

    Directory of Open Access Journals (Sweden)

    Anuradha Nayak Majila

    2015-04-01

    Full Text Available In the present technical paper an iso-symmetrical forging in titanium alloy, i.e., Ti-6Al-4V is chosen for cut-up evaluation and study of mechanical properties and their correlation with microstructural characteristics. Tensile test specimens were extracted from rim, web and bore regions of the forgings aligned in radial and tangential directions. Test specimens varying from various locations were extracted to conduct the tests (ASTM E8 at various temperatures from room temperature to 300 °C. Statistical analyses of the tested data were carried out to quantify the variation in tensile properties along rim, web, and bore regions at room temperature. Effects of radial and tangential alignments of specimens at room temperature was also studied. Among the different test specimens, the specimen that exhibited mechanical properties close to average values were further subjected to microstructural and fractographic investigations using optical and scanning electron microscopes. These studies revealed that there is a marginal inhomogenity in the microstructure of the forgings and this variation controls the mechanical properties and fracture characteristics of the material. Microstructure marginally varies from rim to bore region. Similarly, along the thickness of the forging, there is a small variation in the microstructure. The aforementioned correlations have established the fact that the microstructure variations from different locations and among different specimen orientations have resulted in mild variation in the tensile properties.Defence Science Journal, Vol. 65, No. 2, March 2015, pp.171-178, DOI:http://dx.doi.org/10.14429/dsj.65.7232

  12. Delayed cementless total hip arthroplasty for neglected dislocation of hip combined with complex acetabular fracture and deficient bone stock

    Directory of Open Access Journals (Sweden)

    Gavaskar Ashok S

    2012-12-01

    Full Text Available 【Abstract】Total hip arthroplasty (THA for an un-treated acetabular fracture is technically challenging and the long-term result is not so favorable. A 45-year-old fe-male patient with untreated column and comminuted poste-rior wall fracture of the acetabulum was treated in our insti-tution by reconstruction of the posterior wall using iliac strut autograft and plate stabilization of the posterior col-umn with cancellous grafting and cementless THA in a single stage. At 3 years’ follow-up, the patient was independently mobile without limb length discrepancy. Radiological evalu-ation showed well integrated components and bone grafts. No evidence of aseptic loosening or osteolysis was found. This report aims to emphasize that bony acetabular recon-struction allows the use of primary hip components, which improves prosthesis longevity and preserves bone stock for a future revision. Key words: Acetabulum; Fractures, bone; Hip dislocation; Arthroplasty, replacement, hip

  13. Stable Fixation of a Cementless, Proximally Coated, Double Wedged, Double Tapered Femoral Stem in Total Hip Arthroplasty

    DEFF Research Database (Denmark)

    Nebergall, Audrey K; Rolfson, Ola; Rubash, Harry E;

    2016-01-01

    BACKGROUND: The objective of this 5-year prospective study of 51 hips was to assess migration of a cementless tapered femoral stem using radiostereometric analysis (RSA), plain radiographs (radiolucencies), and patient-reported outcome measures (PROMs). METHODS: Forty-seven patients (51 hips......) agreed to participate in this prospective RSA study. All patients received a Taperloc stem. Tantalum beads were inserted into the femoral bone surrounding the stem to measure migration using RSA. RSA films, plain radiograph, and PROM follow-up were obtained immediately after surgery, 6 months, 1, 2, 3...... year remain stable at 5 years. RSA was the most sensitive method of detection for stems at greater risk for potential future failure. This report adds contributions to the positive results associated with this type of fixation. The results at 5 years showed excellent midterm survivorship in this cohort...

  14. Do Rerevision Rates Differ After First-time Revision of Primary THA With a Cemented and Cementless Femoral Component?

    DEFF Research Database (Denmark)

    Gromov, Kirill; Pedersen, Alma B; Overgaard, Søren;

    2015-01-01

    ) and 2 years (range, 0-16 years), respectively. Survival of first revision THA, with second revision of the femur as outcome, was evaluated using hazard ratios (HRs) with 95% confidence interval (CI) adjusting for potential confounding. All patient- and surgery-related data are collected from Danish...... adjusting for the most likely confounding factors. Our data suggest that increased use of cementless fixation in primary THA may lead to inferior survivorship of first revision THA. Level III, therapeutic study....... results of future revision procedures; however, this has not been documented. The purpose of this study was to compare (1) the risk for rerevision of first revision THA; (2) the patterns of femoral bone loss at the time of first revision of primary THA; (3) the reasons for first revision of primary THA...

  15. The Influence of Technological Conditions of the Process of Cogging in Flat Dies on the Quality of Two-Phase Titanium Alloys

    Directory of Open Access Journals (Sweden)

    Dyja Н.

    2016-06-01

    Full Text Available To create a rational technology of cogging process and to determinate the optimal values of the angles of tilt and single reduction the stress-strain state (SSS of the blank during cogging in the flat dies was analyzed. By using the finite element method and program MSC.SuperForge quantitative data are obtained and the basic patterns of distribution of SSS, the temperature during the simulation of tilting in flat dies with different angles of tilting and the amount of reduction were established. Sustainable experimental-industrial technology of forging of two-phase titanium alloys was developed and tested.

  16. Sustained load crack growth design data for Ti-6Al-4V titanium alloy tanks containing hydrazine

    Science.gov (United States)

    Lewis, J. C.; Kenny, J. T.

    1976-01-01

    Sustained load crack growth data for Ti-6Al-4V titanium alloy in hydrazine per MIL-P-26536 and refined hydrazine are presented. Fracture mechanics data on crack growth thresholds for heat-treated forgings, aged and unaged welds, and aged and unaged heat-affected zones are reported. Fracture mechanics design curves of crack growth threshold stress intensity versus temperature are generated from 40 to 71 C.

  17. 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.

  18. Building on success, forging new ground: The question of sustainability

    OpenAIRE

    Waters, Donald J.

    2004-01-01

    Building on success, forging new ground: The question of sustainability by Donald J. Waters This paper focuses on three factors that contribute to the sustainability of digital scholarly resources. First, the development of such resources depends on a clear definition of the audience and the needs of users. Second, the resource must be designed to take advantage of economies of scale. Third, to create an enduring resource, careful attention is needed to the design of the organization t...

  19. Constitutive Equation of Superalloy In718 in Hammer Forging Process

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A constitutive equation reflecting the flow behavior ofSuperalloy In718 during the counter-blow hammer forging process was developed in terms of the relationship of flow stress and hot-deformation parameters, such as strain, strain rate, and deformation temperature. A new simplified approach for the complex multi-pass stress-strain curves has been attempted. The simulation curves calculated by constitutive equation are consistent with the experimental data.

  20. Forging and Rolling of magnesium alloy AZ61

    Directory of Open Access Journals (Sweden)

    M. Greger

    2007-01-01

    Full Text Available Purpose: The paper summarises results of experiments aimed at development of structure of modified alloyAZ61 at hot deformation.Design/methodology/approach: Deformation behaviour of alloy was verified at the temperature of 420°C byrolling at 380°C by forging, respectively.Findings: Magnesium alloy AZ 61 have hexagonal structure and their forming is at room temperatures verydifficult, that’s why big plastic deformations are carried out in hot condition. After plastic deformations wasobtained that original grain size decreased 15 times.Research limitations/implications: This paper provide data about magnitude of deformation, strain rate andtemperature of forming at different techniques of plastic deformation. It was aimed to determine the conditionsfor non problem rolling and forging respectively.Practical implications: Initial structure was as cast and after heat treatment T4. Heat treatment appeared muchbetter for forming as well as forging than rolling because of state of stress.Originality/value: Role of βphase (Mg17Al12 in these alloys at plastic forming is very important, such thathow it was obtained, best final properties of AZ 61 alloy supports very fine particles, distributed into Mg matrix.Next a relevant information is that multi stage forming process is much better in comparison with a big singlereduction.

  1. Superplasticity in titanium alloys

    OpenAIRE

    J. Sieniawski; Motyka, M.

    2007-01-01

    Purpose: The paper reports characteristic of superplasticity phenomenon in titanium alloys and possibility of its applications.Design/methodology/approach: The main objective of the paper is to show features of superplastic forming of titanium alloys and current research trends aiming at widespread application of this technology.Findings: In the paper characteristic of selected superplastic titanium alloys was presented. The effect of microstructural parameters on superplasticity was consider...

  2. Development of the Dynamic Globularization Prediction Model for Ti-17 Titanium Alloy Using Finite Element Method

    Science.gov (United States)

    Jia, Zhiqiang; Zeng, Weidong; Xu, Jianwei; Zhou, Jianhua; Wang, Xiaoying

    2015-04-01

    In this work, a finite element method (FEM) model for predicting dynamic globularization of Ti-17 titanium alloy is established. For obtaining the microstructure evolution during dynamic globularization under varying processing parameters, isothermal hot compression tests and quantitative metallographic analysis were conducted on Ti-17 titanium alloy with initial lamellar microstructure. The prediction model, which quantitatively described the non-linear relationship between the dynamic globularization fraction and the deformation strain, temperature, and strain rate, was developed on the basis of the Avrami equation. Then the developed model was incorporated into DEFORM software as a user subroutine. Finally, the large-sized step-shaped workpiece was isothermally forged and corresponding FEM simulation was conducted to verify the reliability and accuracy of the integrated FEM model. The reasonable coincidence of the predicted results with experimental ones indicated that the established FEM model provides an easy and a practical method to predict dynamic globularization for Ti-17 titanium alloy with complex shape.

  3. 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.

  4. Influence of Processing Parameters on Grain Size Evolution of a Forged Superalloy

    Science.gov (United States)

    Reyes, L. A.; Páramo, P.; Salas Zamarripa, A.; de la Garza, M.; Guerrero-Mata, M. P.

    2016-01-01

    The microstructure evolution of nickel-based superalloys has a great influence on the mechanical behavior during service conditions. Microstructure modification and the effect of process variables such as forging temperature, die-speed, and tool heating were evaluated after hot die forging of a heat-resistant nickel-based alloy. Forging sequences in a temperature range from 1253 to 1323 K were considered through experimental trials. An Avrami model was applied using finite element data to evaluate the average grain size and recrystallization at different evolution zones. It was observed that sequential forging at final temperatures below 1273 K provided greater grain refinement through time-dependent recrystallization phenomena. This investigation was aim to explore the influence of forging parameters on grain size evolution in order to design a fully homogenous and refined microstructure after hot die forging.

  5. Modelling and experimental research in hot precision forging of shaft gear

    Directory of Open Access Journals (Sweden)

    Wang Baoyu

    2015-01-01

    Full Text Available In this paper, a hot forging die set is designed for a shaft gear. A finite element software DEFORM was employed to simulate the hot forging process. The forming parameter range was determined and the forging force was predicted. The metal flow law in hot forging processes was studied using metal flow analysis and point tracking analysis. The metal flow law was further analysed through finite element simulations and precision forging experiments. The accuracy of hot formed gears is analysed and the deviation of the tooth profile reaches the 8th grade, which meet the defined requirement. The pitch cumulative deviation of the forged part is low enough for practical applications.

  6. Production of ultra-pure steel intended for forged elements

    Directory of Open Access Journals (Sweden)

    A. Michaliszyn

    2012-12-01

    Full Text Available Purpose: The purpose of this research is to analyse the technology of making ultra-pure steel intended for casting forging ingots. Forging ingots, whose mass amounts to 8 Mg, are cast using the bottom pouring method after vacuum steel degassing in the ladle.Design/methodology/approach: Data from 24 melts were analysed. Researchers studied not only the final content of oxygen, sulphur and hydrogen after vacuum steel refinement but also the quantitative amount of nonmetallic inclusions in forgings made of ingots. A simulation was also conducted. Its purpose was to assess the optimal share of bauxite in the production of refining slag. The simulation was performed using thermodynamic software called FactSage 5.5.Findings: Analysing the final concentration of oxygen dissolved in liquid steel led to a conclusion that approx. 90% of analysed types of steel can be categorized as ultra-pure. The simulation results concerning refining slag formation show that the use of bauxite as a slag forming additive lead to an increase in the liquid phase, and what follows, a decrease in the share of solid precipitations – including the precipitations of lime.Research limitations/implications: It was concluded that all stages of ultra-pure steel production must be conducted conscientiously and meticulously. It is also necessary to improve the conditions of vacuum steel refining process by equipping steelworks with a new vacuum device, e.g. of VOD type.Practical implications: If all stages of steel making are conducted conscientiously and meticulously and the steelworks are equipped with a device for vacuum steel refinement, then the produced steel (from the point of view of quality can be competitive in the market of the ultra-pure steel intended for forged products.Originality/value: The simulation results concerning the production of refining slag show that the use of bauxite as a slag forming material leads to an increase in the share of liquid phase. Refining

  7. A forgótőke és elemeinek értelmezése, valamint a forgótőke-menedzsment

    OpenAIRE

    Pupos, Tibor; Peter, Zsolt; Kis-Simon, Tunde; Arnold, Gor

    2010-01-01

    Többéves kutatómunkánk eredményei alapján – jelen tanulmányban – az elméleti összefüggések tisztázásával definiáljuk a forgótőke, az idényszerűen jelentkező forgóeszközök, a forgóbefektetés, a nettó forgótőke, működő tőke és ezekkel összefüggésben a forgótőke-menedzsment fogalmakat. A forgótőke-menedzsment nem egyéb, mint a termelési folyamat gazdaságtana. Mint diszciplína, a termelési folyamat gazdasági vetületét veszi alapul, a körforgás elemeivel és a forgótőkével való gazdálkodás – készle...

  8. Classification of titanium dioxide

    International Nuclear Information System (INIS)

    In this work the X-ray diffraction (XRD), Scanning Electron Microscopy (Sem) and the X-ray Dispersive Energy Spectroscopy techniques are used with the purpose to achieve a complete identification of phases and mixture of phases of a crystalline material as titanium dioxide. The problem for solving consists of being able to distinguish a sample of titanium dioxide being different than a titanium dioxide pigment. A standard sample of titanium dioxide with NIST certificate is used, which indicates a purity of 99.74% for the TiO2. The following way is recommended to proceed: a)To make an analysis by means of X-ray diffraction technique to the sample of titanium dioxide pigment and on the standard of titanium dioxide waiting not find differences. b) To make a chemical analysis by the X-ray Dispersive Energy Spectroscopy via in a microscope, taking advantage of the high vacuum since it is oxygen which is analysed and if it is concluded that the aluminium oxide appears in a greater proportion to 1% it is established that is a titanium dioxide pigment, but if it is lesser then it will be only titanium dioxide. This type of analysis is an application of the nuclear techniques useful for the tariff classification of merchandise which is considered as of difficult recognition. (Author)

  9. Titanium and titanium alloy strip, sheet, and plate

    International Nuclear Information System (INIS)

    The specification covers annealed titanium and titanium alloy strip, sheet, and plate as follows: Grade 1 to 4 unalloyed titanium Grade 5, 6, 10, and 12 titanium alloy; and Grade 7 and 11 unalloyed titanium plus palladium. The specification includes basis of purchase, chemical requirements, mechanical properties, permissible variations in dimensions, finish, sampling for chemical analysis, methods of chemical analysis, rejection, reports, marking, and packaging

  10. TITANIUM DAN PADUAN TITANIUM MATERIAL PILIHAN KEDOKTERAN GIGI MASA DEPAN

    OpenAIRE

    Bambang Irawan

    2015-01-01

    Nowadays, Titanium is used for dental implants, orthodontic wires an denture bases. In Indonesia they have been widely use especially for the orthodontic treatment. Survey conducted by students from University of Indonesia showed that users have little understanding in properties of Titanium. The article describes various matters on characteristic of Titanium. Titanium has low density, low elastic modulus, high tensile strength make attractive for use in dentistry. Titanium forms a very stabl...

  11. Friction and wear in hot forging of steels

    International Nuclear Information System (INIS)

    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

  12. Fractography analysis of tool samples used for cold forging

    DEFF Research Database (Denmark)

    Dahl, K.V.

    2002-01-01

    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...... than the ones constructed in traditional steel, which is connected to differences in micro-structure. Focus has been put on differences in the size anddistribution of car-bides. It is found that the third generation steel contains smaller and more finely dis-persed carbides and has an increased...

  13. Automated ultrasonic shop inspection of reactor pressure vessel forgings

    International Nuclear Information System (INIS)

    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

  14. 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...... in the range 30-150°C. Above this temperature range friction increases. As regards lubricant performance Lubrication Limit Curves (LLC) are plotted in a sliding length-surface enlargement diagram with the tool temperature as a parameter. Larger tool temperature implies lower acceptable surface...

  15. Environmentally Benign Lubricant Systems For Cold, Warm And Hot Forging

    DEFF Research Database (Denmark)

    Bay, Niels

    The growing awareness of environmental issues and the requirements to establish solutions diminishing the impact on working environment as well as external environment has initiated ever increasing efforts to develop new, environmentally benign tribological systems for metal forming. The present...... 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...

  16. Effect of alloy composition on the volume fraction of beta phase in duplex titanium alloys

    International Nuclear Information System (INIS)

    Titanium alloys are strong, light, corrosion resistant and superplastic. While many of them show superplastic behavior, working and forging temperatures are still high, 850-925 degree C, and their range is narrow. Moreover, the material's resistance to deformation is not negligible and, therefore, the cost of making dies and presses for forging or hot deformation is high and it poses a serious problem. To increase the efficiency and to reduce the temperature of hot deformation, increasing the volume fraction of the beta phase present in duplex titanium alloys is suggested. With the introduction of the beta-modified Ti-6Al-4V alloy the decrease in the temperature and the increase in the strain rate of the superplastic regime promise to make superplastic forming of this alloy even more economical, and many researches have been made. In this study, efforts are put on designing new duplex alloys based on the Ti-6Al-4V and Ti-Al-Fe systems, which will have a beta volume fraction of 40-50 percent at around 800 degree C. To accomplish this, experimental volume fractions of the beta phase in several titanium alloys are being compared with predicted and calculated ones using phase equilibria analyses and some suggestions will be made on modifying the alloy compositions. For comparison, the quaternary Ti-V-Fe-Al system and their subsystems are chosen due to availability of both experimental and thermodynamic data

  17. Research on Double CCD Dimensional Metrology Applying in Large Forge Piece

    Energy Technology Data Exchange (ETDEWEB)

    Hu, C H; Xiong, Z [College of Electrical Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2006-10-15

    As development of computer vision, stereoscopic vision sensors have been used more and more widely, and double CCD vision sensor with its simplicity of operator, highaccuracy and high-efficiency has been used in many spheres. It can be used in dimensional metrology of large forge piece, which greatly improves the efficiency and accuracy of large forge piece measurement.

  18. Forging; Heat Treating and Testing; Technically Oriented Industrial Materials and Process 1: 5898.05.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    The course provides students with advanced and exploratory experience in the area of plastic deformation of metals and in the changing of the physical characteristics of metals by the controlled application and timed removal of heat. Course content includes goals, specific objectives, safety in forge work, forging tools and equipment, industrial…

  19. 76 FR 8773 - Forged Stainless Steel Flanges From India and Taiwan

    Science.gov (United States)

    2011-02-15

    ... COMMISSION Forged Stainless Steel Flanges From India and Taiwan AGENCY: United States International Trade... reviews, * * *'' (76 FR 5331). Accordingly, pursuant to section 751(c) of the Tariff Act of 1930 (19 U.S.C... in November 2010 to determine whether revocation of the antidumping duty orders on forged...

  20. MM 99.58 Physical modelling of Hammerhead forging, Vertical and Lateral load history

    DEFF Research Database (Denmark)

    Arentoft, Mogens; Eriksen, Morten; Wanheim, Tarras;

    1999-01-01

    The present report presents a laboratory setup with hammerhead forging, where the vertical and lateral force history is obtained under different process conditions......The present report presents a laboratory setup with hammerhead forging, where the vertical and lateral force history is obtained under different process conditions...

  1. Research on Double CCD Dimensional Metrology Applying in Large Forge Piece

    International Nuclear Information System (INIS)

    As development of computer vision, stereoscopic vision sensors have been used more and more widely, and double CCD vision sensor with its simplicity of operator, highaccuracy and high-efficiency has been used in many spheres. It can be used in dimensional metrology of large forge piece, which greatly improves the efficiency and accuracy of large forge piece measurement

  2. Microstructure Modeling of a Ni-Fe-Based Superalloy During the Rotary Forging Process

    Science.gov (United States)

    Loyda, A.; Hernández-Muñoz, G. M.; Reyes, L. A.; Zambrano-Robledo, P.

    2016-06-01

    The microstructure evolution of Ni-Fe superalloys has a great influence on the mechanical behavior during service conditions. The rotary forging process offers an alternative to conventional bulk forming processes where the parts can be rotary forged with a fraction of the force commonly needed by conventional forging techniques. In this investigation, a numerical modeling of microstructure evolution for design and optimization of the hot forging operations has been used to manufacture a heat-resistant nickel-based superalloy. An Avrami model was implemented into finite element commercial platform DEFORM 3D to evaluate the average grain size and recrystallization during the rotary forging process. The simulations were carried out considering three initial temperatures, 980, 1000, and 1050 °C, to obtain the microstructure behavior after rotary forging. The final average grain size of one case was validated by comparing with results of previous experimental work of disk forging operation. This investigation was aimed to explore the influence of the rotary forging process on microstructure evolution in order to obtain a homogenous and refined grain size in the final component.

  3. A New Method for Controlling Billet Temperature During Isothermal Die Forging of a Complex Superalloy Casing

    Science.gov (United States)

    Lin, Y. C.; Wu, Xian-Yang

    2015-09-01

    Isothermal die forging is one of near net-shape metal-forming technologies. Strict control of billet temperature during isothermal die forging is a guarantee for the excellent properties of final product. In this study, a new method is proposed to accurately control the billet temperature of complex superalloy casing, based on the finite element simulation and response surface methodology (RSM). The proposed method is accomplished by the following two steps. Firstly, the thermal compensation process is designed and optimized to overcome the inevitable heat loss of dies during hot forging. i.e., the layout and opening time of heaters assembled on die sleeves are optimized. Then, the effects of forging speed (the pressing velocity of hydraulic machine) and its changing time on the maximum billet temperature are discussed. Furthermore, the optimized forging speed and its changing time are obtained by RSM. Comparisons between the optimized and conventional die forging processes indicate that the proposed method can effectively control the billet temperature within the optimal forming temperature range. So, the optimized die forging processes can guarantee the high volume fraction of dynamic recrystallization, and restrict the rapid growth of grains in the forged superalloy casing.

  4. Experimental and Numerical Analyses of the Pull-out Response of a Steel Post/Bovine Bone Cementless Fixation

    Institute of Scientific and Technical Information of China (English)

    Khaled Gammoudi; Mohamed Kharrat; Maher Dammak

    2012-01-01

    Effect of initial interference fit on pull-out strength in cementless fixation between bovine tibia and smooth stainless steel post was investigated in this study.Compressive behavior of bovine spongious bone was studied using mechanical testing in order to evaluate the elastic-plastic properties in different regions of the proximal tibia.Friction tests were carried out in the aim to evaluate the friction behavior of the contact between bovine spongious bone and stainless steel.A cylindrical stainless steel post inserted in a pre-drilled bovine tibia with an initial interference fit was taken as an in vitro model to assess the contribution of post fixation to the initial stability of the Total Knee Arthroplasty (TKA) tibial component.Pull-out experiments were carried out for different initial interference fits.Finite Element Models (FEM) using local elastic-plastic properties of the bovine bone were developed for the analysis of the experimental ultimate pull-out force results.At the post/bone interface,Coulomb friction was considered in the FEM calculations with pressure-dependent friction coefficient.It was found that the FEM results of the ultimate force are in good agreement with the experimental results.The analysis of the FEM interfacial stresses indicates that the micro-slip initiation depends on the local bone properties.

  5. Trade-off between stress shielding and initial stability on an anatomical cementless stem shortening: in-vitro biomechanical study.

    Science.gov (United States)

    Yamako, Go; Chosa, Etsuo; Totoribe, Koji; Watanabe, Shinji; Sakamoto, Takero

    2015-08-01

    Shortened cementless femoral stems have become popular with the advent of minimally invasive total hip arthroplasty (THA). Successful THA requires initial stem stability and prevention of stress shielding-mediated bone loss, although the effect of stem shortening is controversial. Here we experimentally examined whether stem shortening affects stress shielding and initial stability. Anatomical stems (length, 120 mm) were cut to an 80 mm or 50 mm length. Ten tri-axial strain gauges measured the cortical strain on each stem-implanted femur to evaluate stress shielding. Two transducers measured axial relative displacement and rotation under single-leg stance loading. The 50 mm stem increased the equivalent strains with respect to the original stem in the proximal calcar region (31.0% relative to intact strain), proximal medial region (63.1%), and proximal lateral region (53.9%). In contrast, axial displacement and rotation increased with a decreasing stem length. However, the axial displacement of the 50 mm stem was below a critical value of 150 µm for bone ingrowth. Our findings indicate that, with regard to a reduction in stem length, there is a tradeoff between stress shielding and initial stability. Shortening the stem up to 50 mm can promote proximal load transfer, but bone loss would be inevitable, even with sufficient initial stability for long-term fixation. PMID:26117334

  6. The effects of pulsed low frequency magnetic field in early rehabilitation of patients with cementless total hip arthroplasty

    Directory of Open Access Journals (Sweden)

    Đurović Aleksandar

    2006-01-01

    Full Text Available Introduction: Early rehabilitation of patients with cementless total hip arthroplasty (cTHA includes different physical modalities and pulsed low frequency magnetic field (PLFMF, which effects have not been explored yet. Objective: To investigate the effects of PLFMF which was applied in different doses in early rehabilitation of patients with cTHA. Method: Prospective, controlled, clinical study included 90 patients, divided in three groups with 30 patients each. First two groups were treated with high (group A or low (group B doses of PLFMF, in addition to kinesitherapy. Control group C was treated only with kinesitherapy. Study was completed in three weeks. Results: Subjects of group A had significantly lower pain than group B (p<0.01 and group C (p<0.001 subjects in the first postoperative week. Pain in group B subjects was significantly lower than in group C in all three postoperative weeks (p<0.01. In relation to other two groups, subjects of group A had higher hip Harris score values at the end of the third postoperative week (p<0.05, and they were faster on 10-meter distance at the end of the first postoperative week (p<0.01. Conclusion: PLFMF used in low and high doses for patients with cTHA had significant effects on pain abatement, especially at higher doses. Improvement of function was earlier and more manifested in the group treated with high doses of PLFMF.

  7. The development and production of thermo-mechanically forged tool steel spur gears

    Science.gov (United States)

    Bamberger, E. N.

    1973-01-01

    A development program to establish the feasibility and applicability of high energy rate forging procedures to tool steel spur gears was performed. Included in the study were relatively standard forging procedures as well as a thermo-mechanical process termed ausforming. The subject gear configuration utilized was essentially a standard spur gear having 28 teeth, a pitch diameter of 3.5 inches and a diametral pitch of 8. Initially it had been planned to use a high contact ratio gear design, however, a comprehensive evaluation indicated that severe forging problems would be encountered as a result of the extremely small teeth required by this type of design. The forging studies were successful in achieving gear blanks having integrally formed teeth using both standard and thermo-mechanical forging procedures.

  8. Process Design for Hot Forging of Asymmetric to Symmetric Rib-web Shaped Steel

    Directory of Open Access Journals (Sweden)

    H. Cho

    2003-01-01

    Full Text Available The process design of hot forging, asymmetric to symmetric rib-web shaped steel, which is used for the turnout of express rails has been studied. Owing to the great difference in shape between the initial billet and the final forged product, it is impossible to hot forge the rail in a single stage operation. Therefore, multi stage forging and also die design for each stage are necessary for the production process. The numerical simulation for hot forging of asymmetric shape to symmetric shape was carried out using commercial FEM code, DEFORMTM-2D. Modification of the design and repeated simulation was carried out on the basis of the simulation results. For comparison with the simulation results, a flow analysis experiment using plasticine was also carried out. The results of the flow analysis experiment showed good agreement with those of the simulation.

  9. HYDROGEN-ASSISTED FRACTURE IN FORGED TYPE 304L AUSTENITIC STAINLESS STEEL

    Energy Technology Data Exchange (ETDEWEB)

    Switzner, Nathan; Neidt, Ted; Hollenbeck, John; Knutson, J.; Everhart, Wes; Hanlin, R. [University of Missouri-Kansas City; Bergen, R. [Precision Metal Products; Balch, D. K. [Sandia Natl Laboratory

    2012-09-06

    Austenitic stainless steels generally have good resistance to hydrogen-assisted fracture; however, structural designs for high-pressure gaseous hydrogen are constrained by the low strength of this class of material. Forging is used to increase the low strength of austenitic stainless steels, thus improving the efficiency of structural designs. Hydrogen-assisted racture, however, depends on microstructural details associated with manufacturing. In this study, hydrogen-assisted fracture of forged type 304L austenitic stainless steel is investigated. Microstructural variation in multi-step forged 304L was achieved by forging at different rates and temperatures, and by process annealing. High internal hydrogen content in forged type 304L austenitic stainless steel is achieved by thermal precharging in gaseous hydrogen and results in as much as 50% reduction of tensile ductility.

  10. 76 FR 5331 - Forged Stainless Steel Flanges From India and Taiwan: Final Results of Sunset Reviews and...

    Science.gov (United States)

    2011-01-31

    ... Forged Stainless Steel Flanges From India, 59 FR 5994 (February 9, 1994) and Antidumping Duty Order: Certain Forged Stainless Steel Flanges From Taiwan, 59 FR 5995 (February 9, 1994). On January 23, 2006... Duty Orders: Forged Stainless Steel Flanges from India and Taiwan, 71 FR 3457 (January 23,...

  11. Machining of titanium alloys

    CERN Document Server

    2014-01-01

    This book presents a collection of examples illustrating the resent research advances in the machining of titanium alloys. These materials have excellent strength and fracture toughness as well as low density and good corrosion resistance; however, machinability is still poor due to their low thermal conductivity and high chemical reactivity with cutting tool materials. This book presents solutions to enhance machinability in titanium-based alloys and serves as a useful reference to professionals and researchers in aerospace, automotive and biomedical fields.

  12. Two-stage revision surgery with preformed spacers and cementless implants for septic hip arthritis: a prospective, non-randomized cohort study

    Directory of Open Access Journals (Sweden)

    Logoluso Nicola

    2011-05-01

    Full Text Available Abstract Background Outcome data on two-stage revision surgery for deep infection after septic hip arthritis are limited and inconsistent. This study presents the medium-term results of a new, standardized two-stage arthroplasty with preformed hip spacers and cementless implants in a consecutive series of adult patients with septic arthritis of the hip treated according to a same protocol. Methods Nineteen patients (20 hips were enrolled in this prospective, non-randomized cohort study between 2000 and 2008. The first stage comprised femoral head resection, debridement, and insertion of a preformed, commercially available, antibiotic-loaded cement hip spacer. After eradication of infection, a cementless total hip arthroplasty was implanted in the second stage. Patients were assessed for infection recurrence, pain (visual analog scale [VAS] and hip joint function (Harris Hip score. Results The mean time between first diagnosis of infection and revision surgery was 5.8 ± 9.0 months; the average duration of follow up was 56.6 (range, 24 - 104 months; all 20 hips were successfully converted to prosthesis an average 22 ± 5.1 weeks after spacer implantation. Reinfection after total hip joint replacement occurred in 1 patient. The mean VAS pain score improved from 48 (range, 35 - 84 pre-operatively to 18 (range, 0 - 38 prior to spacer removal and to 8 (range, 0 - 15 at the last follow-up assessment after prosthesis implantation. The average Harris Hip score improved from 27.5 before surgery to 61.8 between the two stages to 92.3 at the final follow-up assessment. Conclusions Satisfactory outcomes can be obtained with two-stage revision hip arthroplasty using preformed spacers and cementless implants for prosthetic hip joint infections of various etiologies.

  13. Comparative analysis of wear mechanism of different types of forging dies

    Directory of Open Access Journals (Sweden)

    A. Mazurkiewicz

    2011-05-01

    Full Text Available Purpose: Hot working dies are influenced by three main factors causing their destruction: the cyclically changeable mechanical loads, intensive thermal shocks, as well as intensive friction, and erosion. The great variety of the shapes of forgings, the material they are made of (carbon steel, alloy steel, brass and the precision of their production – whether they are supposed to undergo further treatment or are considered to be the final products – result in a variety of problems encountered in the production process. In this paper the wear mechanisms of different types of forging dies, covered by the composite layer “nitride layer / PVD coating” were analysed.Design/methodology/approach: In order to estimate the influence of the different shapes of forgings for their wear mechanism, it was decided to that maintenance tests on two series of tools with different shapes made of DIN 1.2344 steel, coated with composite layer “nitrided layer/CrN coating” needed to be taken. The first one was designed for production of gears pre-forging and the second one was designed for the production of steel synchronizer rings.Findings: The abrasive wear together with thermal-mechanical fatigue and plastic strain is a crucial factor of the process of wearing of forging dies for the production of forgings with high dimensional accuracy and not subject to further mechanical treatment. The variety of the shapes of the forging and the precision with which it is made have strong influence on the intensity of the abrasive wear of forging dies.Research limitations/implications: To ensure higher effectiveness of the application of hybrid technologies of surface treatment for the increase of the durability of forging dies, the complex analysis of the influence of such various aspects of the forging process as: surface treatment, the shape of the die and the cooling and lubricating system are necessary on the development of a new generation of dies with

  14. Titanium by design: TRIP titanium alloy

    Science.gov (United States)

    Tran, Jamie

    Motivated by the prospect of lower cost Ti production processes, new directions in Ti alloy design were explored for naval and automotive applications. Building on the experience of the Steel Research Group at Northwestern University, an analogous design process was taken with titanium. As a new project, essential kinetic databases and models were developed for the design process and used to create a prototype design. Diffusion kinetic models were developed to predict the change in phase compositions and microstructure during heat treatment. Combining a mobility database created in this research with a licensed thermodynamic database, ThermoCalc and DICTRA software was used to model kinetic compositional changes in titanium alloys. Experimental diffusion couples were created and compared to DICTRA simulations to refine mobility parameters in the titanium mobility database. The software and database were able to predict homogenization times and the beta→alpha plate thickening kinetics during cooling in the near-alpha Ti5111 alloy. The results of these models were compared to LEAP microanalysis and found to be in reasonable agreement. Powder metallurgy was explored using SPS at GM R&D to reduce the cost of titanium alloys. Fully dense Ti5111 alloys were produced and achieved similar microstructures to wrought Ti5111. High levels of oxygen in these alloys increased the strength while reducing the ductility. Preliminary Ti5111+Y alloys were created, where yttrium additions successfully gettered excess oxygen to create oxides. However, undesirable large oxides formed, indicating more research is needed into the homogeneous distribution of the yttrium powder to create finer oxides. Principles established in steels were used to optimize the beta phase transformation stability for martensite transformation toughening in titanium alloys. The Olson-Cohen kinetic model is calibrated to shear strains in titanium. A frictional work database is established for common alloying

  15. Effects of trace TiB and TiC on microstructure and tensile properties of β titanium alloy

    International Nuclear Information System (INIS)

    In the present work, a β titanium alloy reinforced by trace TiB whiskers and TiC particles was fabricated by common casting and hot-forging. For comparative study, the unreinforced titanium matrix alloy was also fabricated by the same casting and forging process. The microstructure, room temperature, tensile properties and fracture characteristics of the composite and the matrix alloy are presented and discussed. Microstructural analysis of the composite revealed that the reinforcements were uniformly dispersed after forging. The size of the β grains in the composite was refined after solution treatment under the β field. The secondary α lath was also refined during aging heat treatment by the addition of trace boron and carbon. The results of the tensile tests show that the improvement in the strength of the composite can be attributed to the refinement in the grain size and the secondary α lath, while the remarkable reduction in the ductility can be ascribed to the cracking of the reinforcements and the decohesion at the interface between the reinforcements and the matrix

  16. Gear hot forging process robust design based on finite element method

    International Nuclear Information System (INIS)

    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

  17. Materials problems of manufacture of smith forgings of austenitic steels for WWER's

    International Nuclear Information System (INIS)

    The main problems with the forging and heat treatment of steel CSN 17247 (corresponds to steel 08Kh18N10T) include the formation of surface cracks, the occurrence of coarse-grain areas and the achieving of the specified yield strength value. The problems were solved by modifying the technology, namely reducing the maximum initial temperature to 1140 degC and increasing the end forging temperature to 900 degC in the first forging heats, using at least one angular swage in the first and the second heats, reducing the forging temperature to 1050 degC and the end forging temperature to 770 degC in the final forging operations. The objective of the modification is to disturb the primary casting structure as early as in the first two heats, to prevent heritage manifestations of the primary casting structure during following operations, to improve distribution of stress under the swages, which restricts crack formation, and to achieve a higher yield strength value by applying a lower end forging temperature during the last heat. (Ha)

  18. Identification of Project Risks & Risk Breakdown Structure In Manufacture of Heavy Forgings

    Directory of Open Access Journals (Sweden)

    D.K.Singh

    2014-10-01

    Full Text Available Forging companies, especially in the business of manufacture of heavy forged parts are embedded in the supply chain of critical components of capital goods across various industries. These forged parts form a significant portion of the total raw material requirement of the capital goods equipment and is generally on the critical path of project schedule.Failure to meet delivery schedule poses huge threat to the success of the customer’s project. Delivery of these forged items is delayed in an event of failure to meet customer’s quality requirements.Various other uncertainties during the project lifecyclecan also cause delayed delivery. Accordingly, risk management methodologies when employed by the forging supplier to the manufacturing project can result in successful achievement of delivery timelines. The present study is intended to identify the risks (threats to quality and delivery in manufacture of heavy forged components and create a Risk breakdown structure (RBS as a reference for further risk planning by the forging supplier.

  19. 3D Finite Element Analysis of Spider Non-isothermal Forging Process

    Science.gov (United States)

    Niu, Ling; Wei, Wei; Wei, Kun Xia; Alexandrov, Igor V.; Hu, Jing

    2016-06-01

    The differences of effective stress, effective strain, velocity field, and the load-time curves between the spider isothermal and non-isothermal forging processes are investigated by making full use of 3D FEA, and verified by the production experiment of spider forging. Effective stress is mainly concentrated on the pin, and becomes lower closer to the front of the pin. The maximum effective strain in the non-isothermal forging is lower than that in the isothermal. The great majority of strain in the non-isothermal forging process is 1.76, which is larger than the strain of 1.31 in the isothermal forging. The maximum load required in the isothermal forging is higher than that in the non-isothermal. The maximum experimental load and deformation temperature in the spider production are in good agreement with those in the non-isothermal FEA. The results indicate that the non-isothermal 3D FEA results can guide the design of the spider forging process.

  20. 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.

  1. LASER GAS NITRIDING OF TITANIUM AND TITANIUM ALLOYS

    OpenAIRE

    J. J. DAI; Hou, S. Q.

    2009-01-01

    Titanium and titanium alloys are widely used in many fields due to some of their characteristics such as light density, high strength, and excellent corrosion resistance. However, poor mechanical performances limit their practical applications. Laser gas nitriding is a promising method used to improve the surface properties of components. Recent developments on laser gas nitriding of titanium and titanium alloys are reviewed. The processing parameters have important effects on the resulting c...

  2. Large forged components in mechanical engineering and container construction

    International Nuclear Information System (INIS)

    The most modern metallurgical processes are used for the manufacture of large unmachined components, in order to fulfil the qualitative requirements, which have risen enormously in step with the required sizes. The material characteristics determined by various test procedures, such as fracture mechanics, permit an estimate to be made of the permissible size of faults. A large number of heat treatable steels are available for concrete applications. The list starts with the unalloyed and low alloy steels for small diameters and low requirements, and ends with the 3 1/2% NiCrMoV steels for the largest diameters and highest requirements regarding strength and ductility. It is shown from the example of crankshafts that the characteristics in use in concrete applications can be appreciably improved by suitable measures of heat treatment or on the machined forged part. (orig./IHOE)

  3. Mechanism of Annealing Softening of Rolled or Forged Tool Steel

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In order to reduce hardness of rolled or forged steels after annealing and improve processability, the diameter and dispersity of carbides were measured by SEM and quantitative metallography. The microstructure of annealed steel was analyzed by TEM. The effects of the factors such as solute atoms, carbides, grain boundary and interphase boundary were studied. The mechanism of annealing softening of steels was analyzed on the examples of steels H13, S5, S7, X45CrNiMo4, which are treated with new technology. The results showed that the softening of H13, S7, S5 is easier obtained by isothermal or slow cooling annealing from slightly below A1, but hardness of X45CrNiMo4 after annealing is reduced effectively by obtaining coarse lamellar pearlite. Economic results can be obtained from good processability.

  4. Carbide Coating Preparation of Hot Forging Die by Plasma Processing

    Institute of Scientific and Technical Information of China (English)

    DU Wenhua; DU Cong; WANG Huachang; WANG Hongfu; WANG Junyuan

    2012-01-01

    To meet the performance requirements of hot forging die heat resistant layer,the Ni60-SiC coating,Ni60-Cr3C2 coating,and Ni60-WC coating were prepared using W6Mo5Cr4V2 as substrate material with 30%SiC,10%Cr3C2,30%WC powder by means of plasma spraying and plasma spray re-melting and plasma spray welding,respectively.Microstructure of each carbide coating was analyzed,micro-hardness was tested,and mainly thermal parameters of coating were detected.The experimental results show that using plasma spray welding,the performance of 70%Ni60/30%SiC powder is the best,and its micro-hardness can achieved 1100HV,showing good thermal-physical property.

  5. Decomposition of forging die for high speed machining

    CERN Document Server

    Tapie, Laurent

    2009-01-01

    Today's forging die manufacturing process must be adapted to several evolutions in machining process generation: CAD/CAM models, CAM software solutions and High Speed Machining (HSM). In this context, the adequacy between die shape and HSM process is in the core of machining preparation and process planning approaches. This paper deals with an original approach of machining preparation integrating this adequacy in the main tasks carried out. In this approach, the design of the machining process is based on two levels of decomposition of the geometrical model of a given die with respect to HSM cutting conditions (cutting speed and feed rate) and technological constrains (tool selection, features accessibility). This decomposition assists machining assistant to generate an HSM process. The result of this decomposition is the identification of machining features.

  6. 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. PMID:24934422

  7. Effect of Technical Quality of Thermomechanical Die Forging of AA2099 Alloy

    Directory of Open Access Journals (Sweden)

    Łukaszek-Sołek A.

    2014-10-01

    Full Text Available The paper presents the results of investigations of a multicomponent third-generation aluminium alloy, classified as AA2099. The actual forging conditions were determined basing on the assessment of the quality of side surface of specimens subjected to compression in Gleeble 3800 simulator and on flow curves of the alloy, as well as numerical modelling of forging process performed with application of QForm 3D v.7 software. Compression tests were realized at temperatures 400-500 °C, with a strain rate of 0.001-100 s-1, up to a specified constant true strain value of 0.9. Microstructure examination in as-delivered state was performed with application of Leica DM 4000M optical microscope. The obtained results of isothermal deformation of specimens were correlated with the analysis of a characteristic layered pancake-type microstructure. The simulation of die forging of a complex-shape forging (high-current contact tip used in power engineering at the temperature 500 °C, was performed. The shape of a forging makes it possible to fully analyse the influence of thermomechanical process conditions on technical quality of a product. The simulation of forging process showed full correctness of material flow, with no signs of instability. At the same time, the analysis of investigations allowed to prepare and realize the industrial forging trials for a forging of a very complex shape, in a single step, at the temperature 500 °C, with application of thermomechanical treatment. The forging attained high quality of shape and surface. Directional specimens were taken, in order to be subjected to microstructure examination and hardness testing. The data obtained from industrial tests, combined with the results of testing using Gleeble simulator as well as from numerical modelling, make up the guidelines for mechanical processing of AA2099 alloy at the temperatures 470-500 °C.

  8. 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.

  9. Approximate-model Based Estimation Method for Dynamic Response of Forging Processes

    Institute of Scientific and Technical Information of China (English)

    LEI Jie; LU Xinjiang; LI Yibo; HUANG Minghui; ZOU Wei

    2015-01-01

    Many high-quality forging productions require the large-sized hydraulic press machine (HPM) to have a desirable dynamic response. Since the forging process is complex under the low velocity, its response is difficult to estimate. And this often causes the desirable low-velocity forging condition difficult to obtaln. So far little work has been found to estimate the dynamic response of the forging process under low velocity. In this paper, an approximate-model based estimation method is proposed to estimate the dynamic response of the forging process under low velocity. First, an approximate model is developed to represent the forging process of this complex HPM around the low-velocity working point. Under guaranteeing the modeling performance, the model may greatly ease the complexity of the subsequent estimation of the dynamic response because it has a good linear structure. On this basis, the dynamic response is estimated and the conditions for stability, vibration, and creep are derived according to the solution of the velocity. All these analytical results are further verified by both simulations and experiment. In the simulation verification for modeling, the original movement model and the derived approximate model always have the same dynamic responses with very small approximate error. The simulations and experiment finally demonstrate and test the effectiveness of the derived conditions for stability, vibration, and creep, and these conditions will benefit both the prediction of the dynamic response of the forging process and the design of the controller for the high-quality forging. The proposed method is an effective solution to achieve the desirable low-velocity forging condition.

  10. Engine Performance of Precision-forged, Electropolished and Machined Blades of Nimonic 80 and 80A Alloys

    Science.gov (United States)

    Sikora, Paul F; Johnston, James R

    1955-01-01

    An investigation was conducted to determine the effect of electropolishing precision-forged blades and of machining blades from oversize forgings on the engine performance of Nimonic 80 and Nimonic 80A turbine blades. These blades, along with precision-forged blades, were run in a J33-9 turbojet engine. The tests resulted in the following conclusions: (1) Electropolishing of precision-forged blades did not improve engine life relative to the life of nonelectropolished blades. (2) Machining blades from oversize forgings did not improve the engine life of precision-forged blades. (3) The precision-forging and heat-treating practice used in fabricating the blades investigated was such that the surface roughness and oxide penetration was so slight, approximately 0.0005 inch in depth, as to preclude any benefits derived from surface removal by electropolishing or machining.

  11. Carbon/PEEK composite materials as an alternative for stainless steel/titanium hip prosthesis: a finite element study.

    Science.gov (United States)

    Rezaei, Farshid; Hassani, Kamran; Solhjoei, Nosratollah; Karimi, Alireza

    2015-12-01

    Total hip replacement (THR) has been ranked within the most typical surgical processes in the world. The durability of the prosthesis and loosening of prosthesis are the main concerns that mostly reported after THR surgeries. In THR, the femoral prosthesis can be fixed by either cement or cementless methods in the patient's bones. In both procedures, the stability of the prosthesis in the hosted bone has a key asset in its long-term durability and performance. This study aimed to execute a comparative finite element simulation to assess the load transfer between the prosthesis, which is made of carbon/PEEK composite and stainless steel/titanium, and the femur bone. The mechanical behavior of the cortical bone was assumed as a linear transverse isotropic while the spongy bone was modeled like a linear isotropic material. The implants were made of stainless steel (316L) and titanium alloy as they are common materials for implants. The results showed that the carbon/PEEK composites provide a flatter load transfer from the upper body to the leg compared to the stainless steel/titanium prosthesis. Furthermore, the results showed that the von Mises stress, principal stress, and the strain in the carbon/PEEK composites prosthesis were significantly lower than that made of the stainless steel/titanium. The results also imply that the carbon/PEEK composites can be applied to introduce a new optimum design for femoral prosthesis with adjustable stiffness, which can decrease the stress shielding and interface stress. These findings will help clinicians and biomedical experts to increase their knowledge about the hip replacement. PMID:26462678

  12. 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.

  13. Manufacturing of large monoblock LP rotor forgings for nuclear power plants

    International Nuclear Information System (INIS)

    Large commercial monoblock LP rotor forgings of 3.5NiCrMoV steel were manufactured from 360 ton and 420 ton ingots. Vacuum ladle refining process was applied to produce clean ingots, and upsetting and HRR (Heavy Reduction Restraint) forging were carried out to consolidate internal cavities in the ingots. To obtain good and homogeneous mechanical properties throughout a rotor, heat treatment condition was determined using a computer that is named CAHT (Computer Aided Heat Treatment). Satisfactory results were obtained for qualities confirmed by non-destructive and mechanical tests, including fracture toughness and fatigue crack propagation characteristics of large monoblock LP rotor forgings. (author)

  14. Characterization of large 2219 aluminum alloy hand forgings for the space shuttle solid rocket booster

    Science.gov (United States)

    Brennecke, M. W.

    1978-01-01

    The mechanical properties, including fracture toughness, and stress corrosion properties of four types of 2219-T852 aluminum alloy hand forgings are presented. Weight of the forgings varied between 450 and 3500 lb at the time of heat treatment and dimensions exceeded the maximum covered in existing specifications. The forgings were destructively tested to develop reliable mechanical property data to replace estimates employed in the design of the Space Shuttle Solid Rocket Booster (SRB) and to establish minimum guaranteed properties for structural refinement and for entry into specification revisions. The report summarizes data required from the forgers and from the SRB Structures contractor.

  15. Microstructural evolution and mechanical properties of hypereutectic Al–Si alloy processed by liquid die forging

    Indian Academy of Sciences (India)

    F F Wu; S T Li; G A Zhang; F Jiang

    2014-08-01

    The microstructural evolution and mechanical properties of a hypereutectic Al–Si alloy processed by liquid die forging were investigated. It is found that the grain size of the primary Si was significantly reduced by liquid die forging with increased pressure. The volume fraction of eutectic silicon was decreased with increased pressure. By liquid die forging with pressure up to 180 MPa, the average size of the primary Si was reduced to about 18 m, which results in the remarkable increase in the fracture strength and hardness of the hypereutectic Al–Si alloy.

  16. The Effect of Corner Radii and Part Orientation on Stress Distribution of Cold Forging Die

    Directory of Open Access Journals (Sweden)

    Ahmad B.  Abdullah

    2008-01-01

    Full Text Available One of the most critical problems in cold forging is the huge stresses generated from the deformation of metal leads to die failure. The distribution of stresses mainly depends on geometry of the die. An approach to optimal design in cold forging die geometry and orientation are presented in this paper. The impression cold forging dies of the Universal joint was generated using three-dimensional CAD modeling software, SolidWorks. This CAD modeling software coupled with FEA tools, COSMOSWorks. The paper emphasizes on effect of the corner radius and dies orientation on stress distribution.

  17. Periprosthetic wear particle migration and distribution modelling and the implication for osteolysis in cementless total hip replacement.

    Science.gov (United States)

    Alidousti, Hamidreza; Taylor, Mark; Bressloff, Neil W

    2014-04-01

    In total hip replacement (THR), wear particles play a significant role in osteolysis and have been observed in locations as remote as the tip of femoral stem. However, there is no clear understanding of the factors and mechanisms causing, or contributing to particle migration to the periprosthetic tissue. Interfacial gaps provide a route for particle laden joint fluid to transport wear particles to the periprosthetic tissue and cause osteolysis. It is likely that capsular pressure, gap dimensions and micromotion of the gap during cyclic loading of an implant, play defining roles to facilitate particle migration. In order to obtain a better understanding of the above mechanisms and factors, transient two-dimensional computational fluid dynamic simulations have been performed for the flow in the lateral side of a cementless stem-femur system including the joint capsule, a gap in communication with the capsule and the surrounding bone. A discrete phase model to describe particle motion has been employed. Key findings from these simulations include: (1) Particles were shown to enter the periprosthetic tissue along the entire length of the gap but with higher concentrations at both proximal and distal ends of the gap and a maximum rate of particle accumulation in the distal regions. (2) High capsular pressure, rather than gap micromotion, has been shown to be the main driving force for particle migration to periprosthetic tissue. (3) Implant micromotion was shown to pump out rather than draw in particles to the interfacial gaps. (4) Particle concentrations are consistent with known distributions of (i) focal osteolysis at the distal end of the gap and (ii) linear osteolysis along the entire gap length. PMID:24495400

  18. Productive Machining of Titanium Alloys

    OpenAIRE

    Čejka, Libor

    2013-01-01

    This diploma thesis is focused on a productive machining of titanium alloys. At the beginning it deals about titanium and its alloys. It describes chip generation mechanism, tool blunting and surface quality. Further it contains modern strategies of efficient titanium alloys machining. Then it analyzes contemporary manufacturing technology of hinge made of titanium alloy Ti-6Al-4V in Frentech Aerospace s.r.o. company, and at the end finds possibility of savings by inovation of roughing process.

  19. High-temperature Titanium Alloys

    OpenAIRE

    A.K. Gogia

    2005-01-01

    The development of high-temperature titanium alloys has contributed significantly to the spectacular progress in thrust-to-weight ratio of the aero gas turbines. This paper presents anoverview on the development of high-temperature titanium alloys used in aero engines and potential futuristic materials based on titanium aluminides and composites. The role of alloychemistry, processing, and microstructure, in determining the mechanical properties of titanium alloys is discussed. While phase eq...

  20. Functional and radiographic evaluation and quality of life analysis after cementless total hip arthroplasty with ceramic bearings: minimum of 5 years follow-up

    Directory of Open Access Journals (Sweden)

    Rafael Borghi Mortat

    2013-12-01

    Full Text Available Objective: The aim of the study is to analyze and correlate functional and radiographic results and quality of life in patients undergoing cementless total hip arthroplasty with ceramic surface, performed at Hospital Servidor Publico de Sao Paulo from 2001 to 2006. Methods: We retrospectively analyzed 35 hips treated with cementless total hip arthroplasty with ceramic surfaces with a minimum follow-up of 5 years. Functional evaluation was based on the Harris Hip Score (HHS. Radiographic evaluation was based on the method proposed by Charles Engh for evaluation of femoral osseointegration and on DeLee and Charnley zones for acetabulum. Quality of life was assessed by SF-36 questionnaire. Results: The HHS presented excellent and good results in 91% of patients postoperatively (mean of 93.14 points HHS. As for radiographic evaluation, we found excellent results in 100% of evaluated hips (proven osseointegration. SF-36 scores were not compared to the control group for the following components: pain, vitality, mental health and social aspects. The difference between HHS pre and postoperatively had a statistically significant correlation with physical functioning of the SF-36. Conclusion: Total hip arthroplasty with ceramic surface is a treatment that enables functional improvement of the hip and increases quality of life of patients to levels close to those of people without joint diseases.

  1. Industrial experience with titanium

    International Nuclear Information System (INIS)

    Titanium is a reference material for the construction of waste containers in the Canadian Nuclear Fuel Waste Management Program. It has been in industrial service for over 30 a, often in severe corrosion environments, but it is still considered a relatively exotic material with limited operating history. This has arisen because of the aerospace applications of this material and the misconception that the high strength-to-weight ratio dominates the choice of this material. In fact, the advantage of titanium lies in its high reliability and excellent corrosion resistance. It has a proven record in seawater heat exchanger service and a demonstrated excellent reliability even in polluted water. For many reasons it is the technically correct choice of material for marine applications. In this report we review the industrial service history of titanium, particularly in hot saline environments, and demonstrate that it is a viable waste container material, based upon this industrial service history and operating experience. (author)

  2. Titanium metal: extraction to application

    Energy Technology Data Exchange (ETDEWEB)

    Gambogi, Joseph (USGS, Reston, VA); Gerdemann, Stephen J.

    2002-09-01

    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium. In this paper, we discuss all aspects of the titanium industry from ore deposits through extraction to present and future applications. The methods of both primary (mining of ore, extraction, and purification) and secondary (forming and machining) operations will be analyzed. The chemical and physical properties of titanium metal will be briefly examined. Present and future applications for titanium will be discussed. Finally, the economics of titanium metal production also are analyzed as well as the advantages and disadvantages of various alternative extraction methods.

  3. Tensile and creep properties of titanium-vanadium, titanium-molybdenum, and titanium-niobium alloys

    Science.gov (United States)

    Gray, H. R.

    1975-01-01

    Tensile and creep properties of experimental beta-titanium alloys were determined. Titanium-vanadium alloys had substantially greater tensile and creep strength than the titanium-niobium and titanium-molybdenum alloys tested. Specific tensile strengths of several titanium-vanadium-aluminum-silicon alloys were equivalent or superior to those of commercial titanium alloys to temperatures of 650 C. The Ti-50V-3Al-1Si alloy had the best balance of tensile strength, creep strength, and metallurgical stability. Its 500 C creep strength was far superior to that of a widely used commercial titanium alloy, Ti-6Al-4V, and almost equivalent to that of newly developed commercial titanium alloys.

  4. Five-year results of a cementless short-hip-stem prosthesis

    Directory of Open Access Journals (Sweden)

    Ralf H. Wittenberg

    2013-03-01

    Full Text Available Hip prosthesis stems with a short stem length and proximal fixation geometry support a bone-preserving and muscle-sparing implantation and should also allow for revision surgery with a standard hip stem. We present 250 prospectively documented clinical and radiological results from the Metha Short Hip Stem prosthesis (B. Braun-Aesculap, Tuttlingen, Germany after an average follow-up of 4.9 years. The average patient age at surgery was 60 years. Indication for total hip replacement was primary osteoarthrosis (OA (78% of patients, OA based on developmental dyspla- sia of the hip (16%, and other indications (6%. At the last follow-up, the average Harris Hip Score was 97 points. 85% of patients were very satisfied and 14% were satisfied after surgery, whereas 1% were dissatisfied. Pain according to the Visual Analogue Scale improved from 7.4 (min 1.6, max 9.5 pre-operatively to 0.23 (min 0, max 6.6. No joint dislocations occurred when predominantly using 28 mm and 32 mm prosthesis heads. Nine short-stems were revised: three after bacterial infections, two after primary via valsa with penetration of the femoral cortex two and three months after surgery, and three after early aseptic cases of loosening within the first year. A further nine osseously consolidated short-stems had to be replaced due to breakage of the modular titanium cone adapter after an average of 3.1 years (min 1.9, max 4.4. All surgical revisions were performed using primary standard stems. Without taking the material-related adapter failures into account, a five year Kaplan-Meier survival rate of 96.7% (95% confidence interval 93.4-98.3 was determined for the short-stem prostheses. There were no radiological signs of loosening in any of the short-stem prostheses at the last examination. Fine sclerotic lines were detected in Gruen’s AP zones 1 (19% and 2 (10.5%, individual hypertrophies in zone 3 (3.5%, fine seams in zones 4 (5.5% and 5 (4%, without pedestal formations in zone 4

  5. Machining of Titanium Alloys

    OpenAIRE

    Karásek, Jan

    2008-01-01

    The main goal of this work is the analysis of manufacturing costs for the component of wheel´s blower. Followed by setting up the size of specific cutting force for milling operation of the titanium alloy Ti-Al6-Mo2-Cr2-Fe-Si, the used tool was a milling cutter which is made out of sintered carbide with conical and spherical face. The final values which are at intervals of 1500 to 1800 MPa were compared with the values of the Sandvik Coromant firm kc = 1690 MPa, for titanium alloy with the st...

  6. Titanium alkoxide compound

    Science.gov (United States)

    Boyle, Timothy J.

    2007-08-14

    A titanium alkoxide composition is provided, as represented by the chemical formula (OC.sub.6H.sub.5N).sub.2Ti(OC.sub.6H.sub.5NH.sub.2).sub.2. As prepared, the compound is a crystalline substance with a hexavalent titanium atom bonded to two OC.sub.6H.sub.5NH.sub.2 groups and two OC.sub.6H.sub.5N groups with a theoretical molecular weight of 480.38, comprising 60.01% C, 5.04% H and 11.66% N.

  7. Sensitivity Analysis Based Multiple Objective Preform Die Shape Optimal Design in Metal Forging

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The multiple objective preform design optimization was put forward. The final forging's shape and deformation uniformity were considered in the multiple objective. The objective is to optimize the shape and the deformation uniformity of the final forging at the same time so that a more high integrate quality of the final forging can be obtained. The total objective was assembled by the shape and uniformity objective using the weight adding method. The preform die shape is presented by cubic B-spline curves. The control points of B-spline curves are used as the design variables. The forms of the total objective function, shape and uniformity sub-objective function are given. The sensitivities of the total objective function and the sub-objective functions with respect to the design variables are developed. Using this method, the preform die shape of an H-shaped forging process is optimally designed. The optimization results are very satisfactory.

  8. Accuracy Assessment Points for Valley Forge National Historical Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This shapefile includes the accuracy assessment points used to assess the association-level vegetation map of Valley Forge National Historic Park developed by the...

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

    International Nuclear Information System (INIS)

    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)

  10. Field Plot Points Modified for Valley Forge National Historical Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This shapefile includes the locations of vegetation classification sampling plots used to develop an association-level vegetation classification of Valley Forge...

  11. Prediction of Grain Size for Blade Precision Forging Process under Thermo-Mechanical Coupling

    Institute of Scientific and Technical Information of China (English)

    He YANG; Yuli LIU; Wang CAI; Mei ZHAN

    2003-01-01

    Blade precision forging is a high temperature and large plastic deformation process. Interaction of deformation andheat conduction results in producing large temperature unevenness inside the billet. The unevenness has a greateffect on the mechanical prop

  12. Spatial Vegetation Data for Valley Forge National Historical Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The vegetation and landcover of Valley Forge National Historical Park (VAFO) were mapped to the association level of the National Vegetation Classification System...

  13. 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

    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...... 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....

  14. Crack path in aeronautical titanium alloy under ultrasonic torsion loading

    Directory of Open Access Journals (Sweden)

    A. Nikitin

    2016-01-01

    Full Text Available This paper discusses features of fatigue crack initiation and growth in aeronautical VT3-1 titanium alloy under pure torsion loading in gigacycle regime. Two materials: extruded and forged VT3-1 titanium alloys were studied. Torsion fatigue tests were performed up to fatigue life of 109 cycles. The results of the torsion tests were compared with previously obtained results under fully reversed axial loading on the same alloys. It has been shown that independently on production process as surface as well subsurface crack initiation may appear under ultrasonic torsion loading despite the maximum stress amplitude located at the specimen surface. In the case of surface crack initiation, a scenario of crack initiation and growth is similar to HCF regime except an additional possibility for internal crack branching. In the case of subsurface crack, the initiation site is located below the specimen surface (about 200 μm and is not clearly related to any material flaw. Internal crack initiation is produced by shear stress in maximum shear plane and early crack growth is in Mode II. Crack branching is limited in the case of internal crack initiation compared to surface one. A typical ‘fish-eye’ crack can be observed at the torsion fracture surface, but mechanism of crack initiation seems not to be the same than under axial fatigue loading.

  15. Avantages de l'emploi du magnésium forgé pour l'allègement des véhicules [ MagForge: Magnesium forged components for the automotive industry

    NARCIS (Netherlands)

    Chevaleyre, F.; Popescu, M.; Sillekens, W.H.; Ferreres, I.; Kurz, G.; Gourdin, P.; Gantar, G.

    2010-01-01

    This project, under 6th framework programme of the European Commission, aims to provide SME's with the cost-effective knowledge to provide the automotive industry with light forged magnesium-based alloys components. Low density, high mechanical properties and total recyclability pairing with the adv

  16. FEM Analysis and Experimental Verification of the Integral Forging Process for AP1000 Primary Coolant Pipe

    Science.gov (United States)

    Wang, Shenglong; Yu, Xiaoyi; Yang, Bin; Zhang, Mingxian; Wu, Huanchun

    2016-08-01

    AP1000 primary coolant pipes must be manufactured by integral forging technology according to the designer—Westinghouse Electric Co. The characteristics of these large, special-shaped pipes create nonuniform temperatures, effective stress, and effective strain during shaping of the pipes. This paper presents a three-dimensional finite element simulation (3D FEM) of the integral forging process, and qualitatively evaluates the likelihood of forging defects. By analyzing the evolution histories of the three field variables, we concluded that the initial forging temperature should be strictly controlled within the interval 1123 K to 1423 K (850 °C to 1150 °C) to avoid second-phase precipitation. In the hard deformation zones, small strains do not contribute to recrystallization resulting in coarse grains. Conversely, in the free deformation zone, the large strains can contribute to the dynamic recrystallization, favoring grain refinement and closure of voids. Cracks are likely to appear, however, on the workpiece surface when forging leads to large deformations. Based on the simulation results, an eligible workpiece with good mechanical properties, few macroscopic defects, and favorable grain size has been successfully forged by experiments at an industrial scale, which validates the FEM simulation.

  17. Ductility enhancement of EW75 alloy by multi-directional forging

    Directory of Open Access Journals (Sweden)

    M. Hong

    2014-12-01

    Full Text Available In this study, the Mg–7Gd–5Y–1Nd–0.5Zr alloy can reach a high ductility by the process of multi-directional forging, and the evolution of the microstructure, texture and the mechanical properties were discussed systematically. The results show that after the solutionized sample was multi-forged at 500 °C, its grain size can be refined from 292 um to 58 um. As the forging temperature decreased, fine particles precipitated in the matrix. The volume fraction of the particles increased with the forging temperature decreasing, so the nucleation and growth of crystallization were strongly restricted. There was no recrystallization as the forging temperature fell to 410 °C, and the severe deformed grains distributed as streamlines perpendicular to the final compression axis. The texture intensity decreased with increasing forging passes. The sample with best ductility was obtained after compressed at 470 °C, with an elongation to failure of 21% at room temperature, which is increased by 200%, in comparison with that of the samples in solutionized condition. EBSD results revealed that the mean grain size was 15 um. Refined grains as well as the weakened texture were the key factors to its high ductility.

  18. A study on the combined effect of forging and aging in Mg–Y–RE alloy

    International Nuclear Information System (INIS)

    Highlights: ► For the first time a combination of forging and aging has been explored for a magnesium alloy. ► Objective was to maximize the strength-ductility combination of a Mg–Y–RE alloy. ► An excellent combination of high strength (388 MPa) and high ductility (23%) was obtained. - Abstract: The combined effect of forging and aging on microstructural evolution and mechanical properties of a Mg–Y–RE alloy was studied in the present work by employing hardness measurements, tensile tests, optical microscopy (OM), scanning electron microscopy (SEM) and electron back scattered diffraction (EBSD) analysis. The -F temper treated bulk Mg–Y–RE alloy samples were subjected to forging for microstructural refinement and subsequent aging to maximize the strength-ductility combination. The forged samples combined with peak aging treatment (60 h at 180 °C) exhibited an excellent combination of high strength (388 MPa) and high ductility (23%). The combined effect of grain refinement, work hardening, precipitation strengthening and recovery is responsible for the simultaneous improvement of both strength and ductility. A comparative study of age hardening response of forged samples and as received samples showed higher hardenability in forged samples.

  19. A study on the combined effect of forging and aging in Mg-Y-RE alloy

    Energy Technology Data Exchange (ETDEWEB)

    Panigrahi, S.K.; Yuan, W. [Centre for Friction Stir Processing and Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Mishra, R.S., E-mail: rsmishra@mst.edu [Centre for Friction Stir Processing and Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); DeLorme, R.; Davis, B. [Magnesium Elektron North America Inc., Madison, IL 62060 (United States); Howell, R.A.; Cho, K. [Weapons and Materials Research Directorate, U.S. Army Research Laboratory, Aberdeen Proving Grounds, MD 21005 (United States)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer For the first time a combination of forging and aging has been explored for a magnesium alloy. Black-Right-Pointing-Pointer Objective was to maximize the strength-ductility combination of a Mg-Y-RE alloy. Black-Right-Pointing-Pointer An excellent combination of high strength (388 MPa) and high ductility (23%) was obtained. - Abstract: The combined effect of forging and aging on microstructural evolution and mechanical properties of a Mg-Y-RE alloy was studied in the present work by employing hardness measurements, tensile tests, optical microscopy (OM), scanning electron microscopy (SEM) and electron back scattered diffraction (EBSD) analysis. The -F temper treated bulk Mg-Y-RE alloy samples were subjected to forging for microstructural refinement and subsequent aging to maximize the strength-ductility combination. The forged samples combined with peak aging treatment (60 h at 180 Degree-Sign C) exhibited an excellent combination of high strength (388 MPa) and high ductility (23%). The combined effect of grain refinement, work hardening, precipitation strengthening and recovery is responsible for the simultaneous improvement of both strength and ductility. A comparative study of age hardening response of forged samples and as received samples showed higher hardenability in forged samples.

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

    International Nuclear Information System (INIS)

    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.

  1. Sorting Titanium Welding Rods

    Science.gov (United States)

    Ross, W. D., Jr.; Brown, R. L.

    1985-01-01

    Three types of titanium welding wires identified by their resistance to current flow. Welding-wire tester quickly identifies unknown titaniumalloy wire by touching wire with test probe, and comparing meter response with standard response. Before touching wire, tip of test probe dipped into an electrolyte.

  2. Influence of processing parameters on microstructure and tensile properties of TG6 titanium alloy

    International Nuclear Information System (INIS)

    Research highlights: → This paper highlights the relationships among processing parameters, microstructure and tensile properties of TG6 high temperature titanium alloy. → The microstructural evolutions under different processing parameters were studied by the quantitative metallography, and the effects of microstructure on room and high temperature tensile properties of TG6 alloy were analysed by SEM and TEM. → Linear relationships of elongation vs. volume fraction of primary α phase and ultimate tensile strength vs. thickness of lamellar α phase were determined. - Abstract: Near-isothermal forging of the TG6 titanium alloy was conducted on microprocessor-controlled 630 ton hydraulic press at the deformation temperatures ranging from 850 deg. C to 1045 deg. C, the strain rates of 0.0008 s-1, 0.003 s-1 and 0.008 s-1 and the deformation degree from 10% to 70%, and then different double heat treatments were applied to the forged specimens. The microstructural evolutions were researched by optical microscope and the microstructural features, i.e. volume fraction of primary α phase and thickness of lamellar α phase, were measured by means of the image analysis software. The room and high temperature tensile properties were obtained for all the specimens. Effects of microstructure on the properties were analysed by scanning electronic microscope. It was found that tenslie properties depended on microstructural features strongly. The plots of ultimate tensile strength vs. thickness of α lamellae and elongation vs. volume fraction of primary α phase produced straight lines. The liner equations were determined by fitting the experimental date, respectively. Compared to other parameters, heat treatment had more influence on the tensile strength and the tensile plasticity was more sensitive to the forging temperature.

  3. Superplastic forging of aluminum 6061-silicon carbide(P) composites

    Science.gov (United States)

    Memongkol, Napisporn

    This work describes the processing and characterization of mechanically alloyed Al6061-SiCP composites. The SiC dispersion strengthened Al6061 was synthesized by mechanical alloying of SiC powder and Al6061 powder in an argon atmosphere followed by hot pressing or cold compaction and sinter forging in air. The microstructure of the Al-SiC composites showed a fine grain size of Al matrix with SiC particles and dispersoids distributed homogeneously in the Al matrix. The microstructure of unreinforced MA6061 showed a fine grain size with small dispersoids. The preferred orientation in these composites was measured using the neutron diffraction technique. The hot pressed material had a random texture while a preferred texture was developed in the sinter forged samples. The amount of texture developed depends on the applied load but not on the sintering temperature. The compressive strengths of these composites (4%SiC and 8%SiC) were characterized in the temperatures range from 723 to 833K and at strain rates of 10-4 to 10-1 s-1 . The true compressive stress strain curves exhibit strain softening behavior. The results showed significantly higher strength than the base material. The strain rate sensitivity, m, from the compression test is much lower than required for superplastic behavior. Tensile tests on the MA Al-8%SiC composite and MA6061 monolithic material were performed at temperatures of 673, 723, and 773K and strain rates from 10-2 to 10 s-1 . The true tensile stress strain curves show the strain hardening behavior. The relationship between microstructure, texture, densification and mechanical properties was studied and the strengthening mechanisms were identified. Uniaxial consolidation experiments have been conducted at room temperature and elevated temperature for three different powders, Al6061, MA6061 and MA6061-8%SiC. The experiments illustrated that the densification mechanisms of the three different powders at room temperature are similar but they are

  4. Mandibular reconstruction with a bioactive-coated cementless Ti6Al4V modular endoprosthesis in Macaca fascicularis

    NARCIS (Netherlands)

    Chanchareonsook, N.; Tideman, H.; Lee, S.; Hollister, S.J.; Flanagan, C.; Jansen, J.A.

    2014-01-01

    The titanium mandibular modular endoprosthesis fixed with polymethylmethacrylate cement in the medullary space of the mandible has been introduced in previous studies. However, the internal parts of these devices have been found to be prone to loosening and wound dehiscence. The current study introd

  5. Movement Synchrony Forges Social Bonds across Group Divides

    Science.gov (United States)

    Tunçgenç, Bahar; Cohen, Emma

    2016-01-01

    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. PMID:27303341

  6. The effect of niobium contents on mechanical properties of the large forged Cr-Mo-V steel

    International Nuclear Information System (INIS)

    The effect of Niobium(Nb) contents on the mechanical properties of the CrMoV forgings was investigated as a preliminary study to manufacture large forgings having a low Fracture Appearance Transition Temperature(FATT) and high tensile strength. The experimental forgings were varied in the Nb contents as 0%(A), 003%(B) and 0.05%(C). The tensile strength at room temperature and 600 .deg. C were almost equal regardless of Nb contents, while the FATT lowered in order of alloy C(32 .deg. C), B(35 .deg. C), and A(62 .deg. C). These were resulted from the grain refining. The grain size of alloy A was ASTM no. 5.0 and those of B and C were ASTM no. 6.5 respectively. Based on the preliminary experimental results, large forgings containing 0.03%Nb(D) and 0.05%Nb(E) were manufactured from 30 ton ingot and then those mechanical properties were tested. The higher tensile strength was obtained in both D and E forgings, whereas, the FATT of D and E forgings were 33 deg. C and 67 .deg. C, respectively. The ductile fractured surfaces were developed in the forgings D, while serrated fractographes were alternately occurred with the eutectic niobium carbides and ductile dimples in the forgings E. The eutectic NbC and normal matrix were alternately developed in a severely Nb segregated region of the forgings E. The alternated structure might develop a serrate fracture surfaces, which caused forgings E to increase its FATT. Therefore, in order to manufacture large CrMoV forgings by adding Nb, Nb content to be added should be decided by considering segregation of Nb during solidification. The coarse eutectic niobium carbides were formed in the severely Nb segregated region. The serrated fracture might be caused to increase the FATT of large CrMoV forgings containing Nb

  7. A comparative study of zinc, magnesium, strontium-incorporated hydroxyapatite-coated titanium implants for osseointegration of osteopenic rats.

    Science.gov (United States)

    Tao, Zhou-Shan; Zhou, Wan-Shu; He, Xing-Wen; Liu, Wei; Bai, Bing-Li; Zhou, Qiang; Huang, Zheng-Liang; Tu, Kai-Kai; Li, Hang; Sun, Tao; Lv, Yang-Xun; Cui, Wei; Yang, Lei

    2016-05-01

    Surface modification techniques have been applied to generate titanium implant surfaces that promote osseointegration for the implants in cementless arthroplasty. However, its effect is not sufficient for osteoporotic bone. Zinc (Zn), magnesium (Mg), and strontium (Sr) present a beneficial effect on bone growth, and positively affect bone regeneration. The aim of this study was to confirm the different effects of the fixation strength of Zn, Mg, Sr-substituted hydroxyapatite-coated (Zn-HA-coated, Mg-HA-coated, Sr-HA-coated) titanium implants via electrochemical deposition in the osteoporotic condition. Female Sprague-Dawley rats were used for this study. Twelve weeks after bilateral ovariectomy, all animals were randomly divided into four groups: group HA; group Zn-HA; group Mg-HA and group Sr-HA. Afterwards, all rats from groups HA, Zn-HA, Mg-HA and Sr-HA received implants with hydroxyapatite containing 0%, 10% Zn ions, 10% Mg ions, and 10% Sr ions. Implants were inserted bilaterally in all animals until death at 12weeks. The bilateral femurs of rats were harvested for evaluation. All treatment groups increased new bone formation around the surface of titanium rods and push-out force; group Sr-HA showed the strongest effects on new bone formation and biomechanical strength. Additionally, there are significant differences in bone formation and push-out force was observed between groups Zn-HA and Mg-HA. This finding suggests that Zn, Mg, Sr-substituted hydroxyapatite coatings can improve implant osseointegration, and the 10% Sr coating exhibited the best properties for implant osseointegration among the tested coatings in osteoporosis rats. PMID:26952418

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

    Energy Technology Data Exchange (ETDEWEB)

    Yao, B. [Advanced Materials Processing and Analysis Center, and Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816 (United States); Simkin, B.; Majumdar, B. [Materials and Metallurgical Engineering Department, New Mexico Institute of Mining and Technology, Socorro, NM 87801 (United States); Smith, C.; Bergh, M. van den [DWA Aluminum Composites, Chatsworth, CA 91311 (United States); Cho, K. [Weapons and Materials Research Directorate, U.S. Army Research Laboratory, Aberdeen Proving Ground, MD 21005 (United States); Sohn, Y.H., E-mail: Yongho.Sohn@ucf.edu [Advanced Materials Processing and Analysis Center, and Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816 (United States)

    2012-02-28

    Highlights: Black-Right-Pointing-Pointer Grain growth of cryomilled nanocrystalline aluminum during hot forging. Black-Right-Pointing-Pointer Use of hollow cone dark field imaging technique in TEM for grain size measurement. Black-Right-Pointing-Pointer Grain growth model of strain, strain rate and temperature for forging optimization. - Abstract: Grain growth of nanocrystalline aluminum ({sup nc}Al) in trimodal Al metal-matrix-composites (MMCs) during hot forging was investigated. The {sup 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 {sup 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 {sup nc}Al phase in trimodal Al MMCs after hot forging was documented with respect to temperature ranging from 175 Degree-Sign C to 287 Degree-Sign C, true strain ranging from 0.4 to 1.35 and strain rate ranging from 0.1 to 0.5 s{sup -1}. Hollow cone dark field imaging technique was employed to provide statistically confident measurements of {sup 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 {sup 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.

  9. Optimization and mechanical accuracy reliability of a new type of forging manipulator

    Science.gov (United States)

    Chen, Kang; Ma, Chunxiang; Zheng, Maoqi; Gao, Feng

    2015-03-01

    Researches on forging manipulator have enormous influence on the development of the forging industry and national economy. Clamp device and lifting mechanism are the core parts of forging manipulator, and have been studied for longer time. However, the optimization and mechanical accuracy reliability of them are less analyzed. Based on General Function( G F) set and parallel mechanism theory, proper configuration of 10t forging manipulator is selected firstly. A new type of forging manipulator driven by cylinders is proposed. After solved mechanical analysis of manipulator's core mechanisms, expressions of force of cylinders are carried out. In order to achieve smaller force afforded by cylinders and better mechanical characteristics, some particular sizes of core mechanisms are optimized intuitively through the combined use of the genetic algorithms(GA) and GUI interface in MATLAB. Comparing with the original mechanisms, optimized clamp saves at least 8 percent efforts and optimized lifting mechanism 20 percent under maximum working condition. Finally, considering the existed manufacture error of components, mechanical accuracy reliability of optimized clamp, lifting mechanism and whole manipulator are demonstrated respectively based on fuzzy reliability theory. Obtained results show that the accuracy reliability of optimized clamp is bigger than 0.991 and that of optimized lifting mechanism is 0.995. To the whole manipulator under maximum working condition, that value exceeds 0.986 4, which means that optimized manipulator has high motion accuracy and is reliable. A new intuitive method is created to optimize forging manipulator sizes efficiently and more practical theory is utilized to analyze mechanical accuracy reliability of forging manipulator precisely.

  10. High-temperature Titanium Alloys

    Directory of Open Access Journals (Sweden)

    A.K. Gogia

    2005-04-01

    Full Text Available The development of high-temperature titanium alloys has contributed significantly to the spectacular progress in thrust-to-weight ratio of the aero gas turbines. This paper presents anoverview on the development of high-temperature titanium alloys used in aero engines and potential futuristic materials based on titanium aluminides and composites. The role of alloychemistry, processing, and microstructure, in determining the mechanical properties of titanium alloys is discussed. While phase equilibria and microstructural stability consideration haverestricted the use of conventional titanium alloys up to about 600 "C, alloys based on TiPl (or,, E,AINb (0, TiAl (y, and titaniumltitanium aluminides-based composites offer a possibility ofquantum jump in the temperature capability of titanium alloys.

  11. 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

  12. Casting and Mechanized Titanium Restorations

    OpenAIRE

    Madrigal, A.; Lopez, I; Suarez, MJ; Salido, MP.

    2002-01-01

    INTRODUCTION: New materials and methods for clinical dentistry are continuously being introduced. There is a growing interest in the use of titanium as a restorative material for several reasons: its relatively low cost, favorable physical properties and biocompatibility. However, titanium is technically more difficult to handle than conventional metal alloys. There are two fabrication methods for titanium restorations: casting and mechanized (a combination of machine duplication and spark er...

  13. Titanium production for aerospace applications

    OpenAIRE

    Vinicius A. R. Henriques

    2009-01-01

    Titanium parts are ideally suited for advanced aerospace systems because of their unique combination of high specific strength at both room temperature and moderately elevated temperature, in addition to excellent general corrosion resistance. The objective of this work is to present a review of titanium metallurgy focused on aerospace applications, including developments in the Brazilian production of titanium aimed at aerospace applications. The article includes an account of the evolution ...

  14. The effect of abductor muscle and anterior-posterior hip contact load simulation on the in-vitro primary stability of a cementless hip stem

    Directory of Open Access Journals (Sweden)

    Frei Hanspeter

    2010-06-01

    Full Text Available Abstract Background In-vitro mechanical tests are commonly performed to assess pre-clinically the effect of implant design on the stability of hip endoprostheses. There is no standard protocol for these tests, and the forces applied vary between studies. This study examines the effect of the abductor force with and without application of the anterior-posterior hip contact force in the in-vitro assessment of cementless hip implant stability. Methods Cementless stems (VerSys Fiber Metal were implanted in twelve composite femurs which were divided into two groups: group 1 (N = 6 was loaded with the hip contact force only, whereas group 2 (N = 6 was additionally subjected to an abductor force. Both groups were subjected to the same cranial-caudal hip contact force component, 2.3 times body weight (BW and each specimen was subjected to three levels of anterior-posterior hip contact load: 0, -0.1 to 0.3 BW (walking, and -0.1 to 0.6 BW (stair climbing. The implant migration and micromotion relative to the femur was measured using a custom-built system comprised of 6 LVDT sensors. Results Substantially higher implant motion was observed when the anterior-posterior force was 0.6BW compared to the lower anterior-posterior load levels, particularly distally and in retroversion. The abductor load had little effect on implant motion when simulating walking, but resulted in significantly less motion than the hip contact force alone when simulating stair climbing. Conclusions The anterior-posterior component of the hip contact load has a significant effect on the axial motion of the stem relative to the bone. Inclusion of the abductor force had a stabilizing effect on the implant motion when simulating stair climbing.

  15. Microstructural heterogeneities and fatigue anisotropy of forged steels

    International Nuclear Information System (INIS)

    Highlights: → Tomography result: fibering is composed of non-metallic inclusions bands. → Elongated inclusions decreases the: ductility, fracture toughness and fatigue limit. → Cracks initiate from both inclusion clusters and from the bainitic matrix. → The classical self-heating method does not predict the effect of the inclusions. - Abstract: In this study, various experimental methods are employed to determine the anisotropic fatigue behavior of a 25MnCrSiVB6 forged steel (Metasco MC). This material has a bainitic microstructure and contains many elongated non-metallic inclusions in the rolled direction, which are grouped into clusters. Specimens with different orientations relative to the rolling direction have been extracted from a hot rolled bar and the ability of certain experimental techniques to capture the fatigue anisotropy has been tested. Results obtained from monotonic tensile tests and Charpy impact tests show that the material has isotropic fracture strength and anisotropic ductility. The influence of the 'inclusion clusters' is clearly demonstrated via observation of the fracture surfaces. Concerning the fatigue behavior, results from a classical staircase experimental procedure are compared to results from self-heating fatigue tests. For specimens orientated at 0o relative to the rolled direction, microcrack initiation is controlled by the material matrix and the prediction of the fatigue strength with the self-heating method has been observed to be correct. For specimens orientated at 45o and 90o, the elongated manganese sulfide inclusion clusters are the origin of crack initiation and the fatigue strength drops significantly. For this case, it appears that the self-heating method has difficulty predicting the fatigue behavior.

  16. Controlled Forging of a Nb Containing Microalloyed Steel for Automotive Applications

    Science.gov (United States)

    Nakhaie, Davood; Hosseini Benhangi, Pooya; Fazeli, Fateh; Mazinani, Mohammad; Zohourvahid Karimi, Ebrahim; Ghandehari Ferdowsi, Mahmoud Reza

    2012-12-01

    Controlled forging of microalloyed steels is a viable economical process for the manufacture of automotive parts. Ferrite grain refinement and precipitation hardening are the major microstructural parameters to enhance the mechanical properties of the forged components. In the current study, a modified thermomechanical treatment for additional ferrite grain refinement is developed by exploiting the effect of Nb in increasing the T NR (no recrystallization temperature) and via phase transformation from a pancaked austenite. This is accomplished by performing the final passes of forging below the T NR temperature followed by a controlled cooling stage to produce a mixture of fine grained ferrite, small scaled acicular ferrite as well as a limited amount of martensite. The effect of processing parameters in terms of forging strain, cooling rate and aging condition on the microstructure and mechanical properties of a medium carbon, Nb containing microalloyed steel is investigated. An attempt is made to identify a suitable microstructure that provides a proper combination of high strength and good impact toughness. The processing-microstructure relationships for the proposed novel forging procedure are discussed, and directions for further improvements are outlined.

  17. 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.

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

    International Nuclear Information System (INIS)

    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.

  19. 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.

  20. Chemical changes of titanium and titanium dioxide under electron bombardment

    Directory of Open Access Journals (Sweden)

    Romins Brasca

    2007-09-01

    Full Text Available The electron induced effect on the first stages of the titanium (Ti0 oxidation and titanium dioxide (Ti4+ chemical reduction processes has been studied by means of Auger electron spectroscopy. Using factor analysis we found that both processes are characterized by the appearance of an intermediate Ti oxidation state, Ti2O3 (Ti3+.

  1. Chemical changes of titanium and titanium dioxide under electron bombardment

    OpenAIRE

    Romins Brasca; Luciana Ines Vergara; Mario César Guillermo Passeggi; Julio Ferrón

    2007-01-01

    The electron induced effect on the first stages of the titanium (Ti0) oxidation and titanium dioxide (Ti4+) chemical reduction processes has been studied by means of Auger electron spectroscopy. Using factor analysis we found that both processes are characterized by the appearance of an intermediate Ti oxidation state, Ti2O3 (Ti3+).

  2. Evaluation of Die Chilling Effects during Forging of Nimonic-80A Superalloy

    International Nuclear Information System (INIS)

    Nimonic-80A is a kind of nickel-based superalloys which is used in high temperature components of land gas turbines. In this paper, the influence of four design factors: die temperature, strain rate, friction coefficient and geometry size of ring sample over the variation of internal diameters (VID) and forging load (FL) was studied. It was done by means of design methodology based on DOE-designated full factorial and FE simulations. FEM and experimental results showed that the variation of internal diameters and forging load had inverse proportion to the die temperature. Regression models were developed by using the response surface methodology (RSM) for VID and FL. Rate of the dynamic recrystallization varied depending on different amounts of die temperature. The results can be used in the semi-isothermal forging of complex part of the Nimonic-80A.

  3. 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.

  4. 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.

  5. Heuristic algorithm for planning and scheduling of forged pieces heat treatment

    Directory of Open Access Journals (Sweden)

    R. Lenort

    2012-04-01

    Full Text Available The paper presents a heuristic algorithm for planning and scheduling of forged pieces heat treatment which allows maximizing the capacity exploitation of the heat treatment process and the entire forging process. Five Focusing Steps continuous improvement process was selected as a methodological basis for the algorithm design. Its application was supported by simulation experiments performed on a dynamic computer model of the researched process. The experimental work has made it possible to elicit the general rules for planning and scheduling of the heat treatment process of forged pieces which reduce losses caused by equipment conversion and setup times, and which increase the throughput of this process. The HIPO diagram was used to design the algorithm.

  6. Finite element simulation of stretch forging using a mesh condensation method

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In order to reduce the computation time of finite element simulations of stretch forging process,a mesh condensation method is presented and applied to a three-dimensional rigid-viscoplastic finite element program.In this method,a conventional mesh for the whole zone of a workpiece is condensed to a computational mesh for the active deformation zone.Two vital problems are solved,which are automatic construction of the computational mesh and treatment of interfaces between the deformation zone and the rigid zone.The mesh condensation method is compared with conventional finite element method by simulations of a six-bite stretch forging process.Some simulation results including forging load,temperature distribution and effective strain distribution are illustrated.The efficiency and accuracy of this method are verified.

  7. Design of Controlled Processing Conditions for Drop Forgings Made of Microalloy Steel Grades for Mining Industry

    Directory of Open Access Journals (Sweden)

    Skubisz P.

    2015-04-01

    Full Text Available Effect of plastic processing and controlled cooling on microstructure and mechanical properties of experimental steel grades with microalloyed with Ti, V and/or Nb, varying in the content of Mo is presented as an offer for mining industry for replacement traditionally heat-treatable hardenability grades. The goal of the work is producing microstructure condition, which after controlled hot forging and direct heat treatment, involving quenching and self-tempering, are meant to provide good combination of mechanical properties, such as TYS 800 MPa, UTS 1050 MPa, elongation to fracture at least A5 15% and/or impact strength at room temperature KCV 60 J/cm2. Hardenability assessment and dilatometric examination allowed formulation of direct heat treatment guidelines, taking into consideration fields of temperature and strain in a typical hot forging process, estimated numerically, with the use of plastometric tests results, as well as the use of unique cooling cycles after forging.

  8. Analysis Of Potentiometric Methods Used For Crack Detection In Forging Tools

    Science.gov (United States)

    Pilc, Jozef; Drbúl, Mário; Stančeková, Dana; Varga, Daniel; Martinček, Juraj; Kuždák, Viktor

    2015-12-01

    Increased use of forging tools in mass production causes their increased wear and creates pressure to design more efficient renovation process. Renovation is complicated because of the identification of cracks expanding from the surface to the core material. Given that the production of forging tools is expensive, caused by the cost of tool steels and the thermo-chemical treatment, it is important to design forging tool with its easy renovation in mind. It is important to choose the right renovation technology, which will be able to restore the instrument to its original state while maintaining financial rentability. Choosing the right technology is difficult because of nitrided and heat-treated surface for high hardness and wear resistance. Article discusses the use of non-destructive method of detecting cracks taking into account the size of the cracks formed during working process.

  9. Titanium minerals for new materials

    Science.gov (United States)

    Kotova, O.; Ozhogina, E.; Ponaryadov, A.; Golubeva, I.

    2016-04-01

    The mineral composition of titanium minerals of modern coastal-marine placer in Stradbroke Island (Australia) and Pizhma paleoplacer in Middle Timan (Russia) has been presented. The physical features of titanium minerals and their modification methods were shown. Photocatalysts on the basis of the Pizhma leucoxene were developed for water purification.

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

    International Nuclear Information System (INIS)

    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)

  11. 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...

  12. Titanium dioxide nanotube films

    Energy Technology Data Exchange (ETDEWEB)

    Roman, Ioan, E-mail: roman@metav-cd.ro [S.C. METAV-Research and Development S.R.L., Bucharest, 31C. A. Rosetti, 020011 (Romania); Trusca, Roxana Doina; Soare, Maria-Laura [S.C. METAV-Research and Development S.R.L., Bucharest, 31C. A. Rosetti, 020011 (Romania); Fratila, Corneliu [Research and Development National Institute for Nonferrous and Rare Metals, Pantelimon, 102 Biruintei, 077145 (Romania); Krasicka-Cydzik, Elzbieta [University of Zielona Gora, Department of Biomedical Engineering Division, 9 Licealna, 65-417 (Poland); Stan, Miruna-Silvia; Dinischiotu, Anca [University of Bucharest, Department of Biochemistry and Molecular Biology, 36-46 Mihail Kogalniceanu, 050107 (Romania)

    2014-04-01

    Titania nanotubes (TNTs) were prepared by anodization on different substrates (titanium, Ti6Al4V and Ti6Al7Nb alloys) in ethylene glycol and glycerol. The influence of the applied potential and processing time on the nanotube diameter and length is analyzed. The as-formed nanotube layers are amorphous but they become crystalline when subjected to subsequent thermal treatment in air at 550 °C; TNT layers grown on titanium and Ti6Al4V alloy substrates consist of anatase and rutile, while those grown on Ti6Al7Nb alloy consist only of anatase. The nanotube layers grown on Ti6Al7Nb alloy are less homogeneous, with supplementary islands of smaller diameter nanotubes, spread across the surface. Better adhesion and proliferation of osteoblasts was found for the nanotubes grown on all three substrates by comparison to an unprocessed titanium plate. The sensitivity towards bovine alkaline phosphatase was investigated mainly by electrochemical impedance spectroscopy in relation to the crystallinity, the diameter and the nature of the anodization electrolyte of the TNT/Ti samples. The measuring capacity of the annealed nanotubes of 50 nm diameter grown in glycerol was demonstrated and the corresponding calibration curve was built for the concentration range of 0.005–0.1 mg/mL. - Highlights: • Titania nanotubes (TNTs) on Ti, Ti6Al4V and Ti6Al7Nb substrates were prepared. • Quantitative dependences of anodization conditions on TNT features were established. • Morphology and electrochemical tests revealed inhomogeneity of TNT/Ti6Al7Nb films. • Particular characteristics of TNT films induce electrochemical sensitivity to ALP. • Annealed TNT/Ti impedimetric sensitivity towards ALP was demonstrated and quantified.

  13. Layered titanium diphosphonates

    Czech Academy of Sciences Publication Activity Database

    Melánová, Klára; Beneš, L.; Svoboda, Jan; Zima, Vítězslav; Vlček, Milan

    Strasbourg: European Materials Research Society, 2012. P1 6-P1 6. ISBN -. [E- MRS Spring Meeating 2012 – Symposium P Advanced Hybrid Materials II: design and applications. 14.05.2012-18.05.2012, Strasbourg] R&D Projects: GA ČR GA203/08/0208 Institutional support: RVO:61389013 Keywords : titanium diphosphonate * layered compounds * powder x-ray difraction Subject RIV: CA - Inorganic Chemistry http://www.emrs-strasbourg.com/index.php?option=com_content&task=view&Itemid=132&id=479

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

    International Nuclear Information System (INIS)

    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

  15. Development and production of LP rotor forgings made from 670 ton ingot

    International Nuclear Information System (INIS)

    We have been produced mono block low-pressure turbine rotor shaft forgings for the nuclear power plant from ingot weight of up to 600 ton. However, increasing the generator capacity, more than 600 ton ingot shall be necessary to produce them. The Japan Steel Works, Ltd. has manufactured the trial mono block low-pressure turbine rotor shaft forging which diameter of φ3.2m from 670 ton ingot. We have confirmed that the internal quality by ultrasonic examination and the mechanical properties of 670 ton ingot is as same as that of 600 ton ingot. (author)

  16. High speed forging of solid powder discs of large slenderness ratio

    Indian Academy of Sciences (India)

    R K Ranjan; S Kumar

    2004-10-01

    The paper reports an investigation into the forging of a solid powder circular disc with large slenderness ratio (L/D) between two flat dies at high speed. The deformation pattern during the operation is influenced by many factors, which interact with one another in a complex manner. The decisive factors are the interfacial conditions, initial relative density of the preform and the geometry of the preform. An attempt has been made to determine the die pressures developed during such forging, using an upper bound approach. The results so obtained are presented graphically and discussed critically to illustrate the interaction of various process parameters involved.

  17. An upper bound solution for closed die sinter forging of hexagonal shapes

    Indian Academy of Sciences (India)

    R K Ranjan; S Kumar

    2004-06-01

    The paper reports on an investigation into the various aspects of closed die cold forging of hexagonal powder preforms, which have been compacted and sintered from atomized powder. It is found that for certain dimensional ratios of the preform, the die pressure is minimum. An attempt has been made determine the die pressures developed during the closed die forging of the hexagonal powder preform by using an upper bound approach. The results so obtained are discussed critically to illustrate the interaction of various process parameters involved and are presented graphically.

  18. Titanium for salt water service

    International Nuclear Information System (INIS)

    Titanium has potential as major material of construction in desalination plants, in condensers and heat exchangers, in view of its excellent corrosion resistance to salt water upto at least 120deg C. The advantages of titanium in such applications are brought out. The various specific problems such as pitting, crevice and galvanic corrosion and the preventive methods, for adopting titanium have been discussed. The hydriding problem can be overcome by suitably controlling the operating parameters such as temperature and surface preparation. A case has been made to prove the economic viability of titanium in comparison to Al-brass and Cu-Ni alloy. The future of titanium seems to be very promising in view of the negligible tube failures and outages. (auth.)

  19. Biocompatibility of Titanium

    Science.gov (United States)

    Namavar, Fereydoon; Sabirianov, Renat; Marton, Denes; Rubinstein, Alexander; Garvin, Kevin

    2012-02-01

    Titanium is the material of choice for orthopaedic applications because of its known biocompatibility. In order to enhance osteogenic properties of the Ti implants, it is necessary to understand the origin of its biocompatibility. We addresses the origin of Ti biocompatibility through (1) theoretical modeling, (2) the precise determination of Ti surface chemistry by X-ray photoelectron spectroscopy (XPS), (3) and the study of fibronectin adsorption as a function of Ti (near) surface chemistry by Enzyme-linked immunosorbent assay (ELISA). We compare the protein adsorption on Ti with the native oxide layer and the one coated by TiO2 in anatase phase using ion beam assisted deposition (IBAD). We show that the thin native sub-stoichiometric titanium oxide layer is crucial for biocompatibility of Ti surface. This is due to the enhancement of the non-specific adsorption of proteins which mediate cell adhesion. Improving the surface oxide quality, i.e. fabricating stoichiometric TiO2 (using IBAD) as well as nanoengineering the surface topology that matches its dimensions to that of adhesive proteins, is crucial for increased protein adsorption and, as a result, further increases biocompatibility of Ti implant materials.

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

    DEFF Research Database (Denmark)

    Bay, Niels

    2011-01-01

    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...

  1. Prediction of grain size for large-sized aluminium alloy 7050 forging during hot forming

    Institute of Scientific and Technical Information of China (English)

    YI You-ping; FU Xin; CUI Jin-dong; CHEN Hua

    2008-01-01

    A numerical approach for process optimization and microstructure evolution of lager-sized forging of aluminium alloy 7050 Was proposed, which combined a commercial FEM code Deform 3D with empirical models. To obtain the parameters of empirical constitutive equation and dynamic recrystallization models for aluminium alloy 7050. the isothermal compression tests of 7050 samples were performed on Gleeble-1500 thermo-simulation machine in the temperature range of 250-450 ℃ and strain rate of 0.01-10 S-1, and the metallograph analysis of the samples were carried out on a Leica DMIRM image analyzer. The simulation results show that the dynamic recrystallization in the central area of the billet occurs more easily than that on the edge. Repetitious upsetting and stretching processes make the billet deform adequately. Among several forging processes e. g. upsetting, stretching, rounding and flatting. the stretching process is the most effective way to increase the effective strain and refine the microstructure of the billet. As the forging steps increase, the effective strain rises significantly and the average grain size reduces sharply. Recrystallized volume fractions in most parts of the final forging piece reach 100% and the average grain size reduces to 10 μm from initial value of 90 um.

  2. From Pastoralism to Industrial Antipathy in William Attaway's Blood on the Forge

    Science.gov (United States)

    Vaughan, Philip

    1975-01-01

    Asserts that Blood on the Forge, published in 1941 by black novelist, William Attaway, represented a literary achievement in its own right, and at the same time realistically portrayed the transition of a people from a structured, authoritarian, rural existence to an industrialized urban frontier. Attaway rejected traditional forms of agrarianism…

  3. 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…

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

    DEFF Research Database (Denmark)

    Christiansen, Peter; Hattel, Jesper Henri; Bay, Niels; Alves, Luis M.; Martins, Paulo A. F.

    -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...

  5. 76 FR 31585 - Forged Stainless Steel Flanges From India: Notice of Rescission of Antidumping Duty...

    Science.gov (United States)

    2011-06-01

    ... International Trade Administration Forged Stainless Steel Flanges From India: Notice of Rescission of... stainless steel flanges from India. The period of review is February 1, 2010, through January 22, 2011... stainless steel flanges from India. See Antidumping or Countervailing Duty Order, Finding, or...

  6. 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.)

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

    International Nuclear Information System (INIS)

    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.

  8. Path planning and kinematics simulation of surfacing cladding for hot forging die

    Directory of Open Access Journals (Sweden)

    Wang Huajun

    2015-01-01

    Full Text Available During the course of their work, a variety of damage and failure of hot forging die occurs and seriously affect the service life. Multi-layer metal hot forging die with functionally graded material structure can effectively extend the service life. In this paper, According to the needs of strengthening forging cavity, the CAD model of surfacing forming center was designed. Based on technological requirements of surface cladding for die cavity, the coupled movement equation of weld torch was established, and the trajectory of welding positioner and Cartesian robot kinematics was solved. The weld torch path was planned, according to the typical methods used in plane welding, and the surfacing path data was extracted by the secondary development of UG/OPEN. Then the kinematics solver program, which can output the control function of motion simulation, was written in MATLAB to solve the kinematics equation. Finally, in UG NX7.5, the kinematics simulation model was built to verify the correctness of mathematical model and the rationality of welding path planning. The above studies can provide a technical support for the die repair and manufacturing of a multilayer metal forging die.

  9. 75 FR 70689 - Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum-Greenwood Forge Division; Currently...

    Science.gov (United States)

    2010-11-18

    ... in the Federal Register on November 17, 2009 (74 FR 59254). At the request of the State agency and a... Employment and Training Administration Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum- Greenwood... Aluminum Fabricated Products, LLC, Kaiser Aluminum-Greenwood Forge Division, including on- site...

  10. 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…

  11. Effect of key factors on cold orbital forging of a spur bevel gear

    Institute of Scientific and Technical Information of China (English)

    庄武豪; 董丽颖

    2016-01-01

    Cold orbital forging is an advanced spur bevel gear forming technology. Generally, the spur bevel gear in the cold orbital forging process is formed by two steps: the preforming step and the final step. Due to the great importance of the final step to gear forming and its complication with interactive factors, this work aims at examining the influence of key factors on the final step in cold orbital forging of a spur bevel gear. Using the finite element (FE) method and control variate method, the influence rules of four key factors, rotation velocity of the upper tool,n, feeding velocity of the lower tool,v, tilted angle of the upper tool,γ, friction factor between the tools and the billet,m, on the geometry and the deformation inhomogeneity of the cold orbital forged gear are thoroughly clarified. The research results show that the flash becomes more homogeneous with increasingv, increasingm, decreasing n or decreasingγ. And the deformation of the gear becomes more homogeneous with increasingv, decreasingn or decreasingγ. Finally, a corresponding experiment is conducted, which verifies the accuracy of FE simulation conclusions.

  12. 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.)

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

    International Nuclear Information System (INIS)

    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.)

  14. 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...

  15. Beta titanium alloys and their role in the titanium industry

    Science.gov (United States)

    Bania, Paul J.

    1994-07-01

    The class of titanium alloys generically referred to as the beta alloys is arguably the most versatile in the titanium family. Since these alloys offer the highest strength-to-weight ratios and deepest hardenability of all titanium alloys, one might expect them to compete favorably for a variety of aerospace applications. To the contrary, however, except for one very successful application (Ti-13V-11Cr-3Al on the SR-71), the beta alloys have remained a very small segment of the industry. As a perspective on this situation, this article reviews some past and present applications of titanium alloys. It also descibes some unique new alloys and applications that promise to reverse historical trends.

  16. The wear mechanism of hybrid layer “PN+CrN” during the hot forging process

    Directory of Open Access Journals (Sweden)

    J.A. Smolik

    2011-12-01

    Full Text Available Purpose: One of the most perspective development directions of surface engineering is related to hybrid technologies, which best fulfil the expectations of the industry concerning the obtainment of adequate properties of the surface of tools and machine components. The best known and widely employed hybrid technology of surface treatment using the diffusion phenomenon is the combination of gas nitriding or plasma nitriding (PN+CrN followed by the deposition of hard, wear resistant coatings by the PVD methods. In this paper the wear mechanisms of forging dies, covered with the PN+CrN hybrid layer were analysed.Design/methodology/approach: The hybrid layers PN+CrN selected for testing were obtained by means of a multi-stage technology of surface treatment encompassing plasma nitriding (PN and arc-evaporation process. Maintenance tests were conducted at Institut für Umformtechnik und Umformmaschinen in Hannover, according to different forging time.Findings: It was demonstrated that the dominating mechanisms of the wear process of forging dies covered with the PN+CrN hybrid layer are: thermo-mechanical fatigue of the CrN coating and thermo-mechanical fatigue and plastic deformation of steel substrate.Research limitations/implications: The CrN coating is of great importance in the wear process of forging dies covered with the PN+CrN hybrid layer. Very important in the die wear process is the resistance of the CrN coating to brittle cracking. CrN coating reduces, and as a result significantly limits, stresses initiated in the substrate in the forging process by the operation of external impacts. According to the results of simulation tests, 3 µm-thick CrN coating limits stresses initiated in material and hence reduces the possibility of plastic deformation occurrence in substrate.Practical implications: The obtained results of the tests have been practically applied in the surface engineering laboratory to develop modern surface engineering

  17. Hydrogen in titanium alloys

    International Nuclear Information System (INIS)

    The titanium alloys that offer properties worthy of consideration for fusion reactors are Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo-Si (Ti-6242S) and Ti-5Al-6Sn-2Zr-1Mo-Si (Ti-5621S). The Ti-6242S and Ti-5621S are being considered because of their high creep resistance at elevated temperatures of 5000C. Also, irradiation tests on these alloys have shown irradiation creep properties comparable to 20% cold worked 316 stainless steel. These alloys would be susceptible to slow strain rate embrittlement if sufficient hydrogen concentrations are obtained. Concentrations greater than 250 to 500 wppm hydrogen and temperatures lower than 100 to 1500C are approximate threshold conditions for detrimental effects on tensile properties. Indications are that at the elevated temperature - low hydrogen pressure conditions of the reactors, there would be negligible hydrogen embrittlement

  18. The use of β titanium alloys in the aerospace industry

    Science.gov (United States)

    Boyer, R. R.; Briggs, R. D.

    2005-12-01

    Beta titanium alloys have been available since the 1950s (Ti-13V-11Cr-3Mo or B120VCA), but significant applications of these alloys, beyond the SR-71 Blackbird, have been slow in coming. The next significant usage of a β alloy did not occur until the mid-1980s on the B-1B bomber. This aircraft used Ti-15V-3Cr-3Al-3Sn sheet due to its capability for strip rolling, improved formability, and higher strength than Ti-6Al-4V. The next major usage was on a commercial aircraft, the Boeing 777, which made extensive use of Ti-10V-2Fe-3Al high-strength forgings. Ti-15V-3Cr-3Al-3Sn environmental control system ducting, castings, and springs were also used, along with Ti-3Al-8V-6Cr-4Mo-4Zr (β-C) springs. Beta-21S was also introduced for high-temperature usage. More recent work at Boeing has focused on the development of Ti-5Al-5Mo-5V-3Cr, a high-strength alloy that can be used at higher strength than Ti-10V-2Fe-3Al and is much more robust; it has a much wider, or friendlier, processing window. This, along with additional studies at Boeing, and from within the aerospace industry in general will be discussed in detail, summarizing applications and the rationale for the selection of this alloy system for aerospace applications.

  19. Discovery of the Titanium Isotopes

    OpenAIRE

    Meierfrankenfeld, D.; Thoennessen, M.

    2009-01-01

    Twentyfive titanium isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  20. Electrochemical process of titanium extraction

    Institute of Scientific and Technical Information of China (English)

    CH. RVS. NAGESH; C. S. RAMACHANDRAN

    2007-01-01

    A wide variety of processes are being pursued by researchers for cost effective extraction of titanium metal. Electrochemical processes are promising due to simplicity and being less capital intensive. Some of the promising electrochemical processes of titanium extraction were reviewed and the results of laboratory scale experiments on electrochemical reduction of TiO2 granules were brought out. Some of the kinetic parameters of the reduction process were discussed while presenting the quality improvements achieved in the experimentation.

  1. 大型活塞杆锻件的研制%Development & Manufacture of Large Piston Rod Forging

    Institute of Scientific and Technical Information of China (English)

    涂政; 张承峰; 赵林武

    2014-01-01

    In the process of development and manufacture of the piston rod forging , by means of optimizing chemi-cal composition proportioning , selecting feasible forge forming process , and cooling with uniform velocity , each per-formance index for the piston rod forging can meet technical requirements .%在活塞杆锻件的研制过程中,优化化学成分配比,选择合理的锻造成型方法,淬火时匀速冷却,使得活塞杆锻件的各项指标均满足技术要求。

  2. 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...... equations for flow stress in cold as well as hot forging, determination of interface conditions, i.e. friction and heat transfer in cold and hot forging. The developments are validated by physical and numerical modeling and finally verified by analysis of some complex industrial examples....

  3. Low cost titanium--myth or reality

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Paul C.; Hartman, Alan D.; Hansen, Jeffrey S.; Gerdemann, Stephen J.

    2001-01-01

    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium, and titanium cost has prevented its use in non-aerospace applications including the automotive and heavy vehicle industries.

  4. TC17 titanium alloy laser melting deposition repair process and properties

    Science.gov (United States)

    Liu, Qi; Wang, Yudai; Zheng, Hang; Tang, Kang; Li, Huaixue; Gong, Shuili

    2016-08-01

    Due to the high manufacturing cost of titanium compressor blisks, aero engine repairing process research has important engineering significance and economic value. TC17 titanium alloy is a rich β stable element dual α+β phase alloy whose nominal composition is Ti-5Al-2Sn-2Zr-4Mo-4Cr. It has high mechanical strength, good fracture toughness, high hardenability and a wide forging-temperature range. Through a surface response experiment with different laser powers, scanning speeds and powder feeding speeds, the coaxial powder feeding laser melting deposition repair process is studied for the surface circular groove defects. In this paper, the tensile properties, relative density, microhardness, elemental composition, internal defects and microstructure of the laser-repaired TC17 forging plate are analyzed. The results show that the laser melting deposition process could realize the form restoration of groove defect; tensile strength and elongation could reach 1100 MPa and 10%, which could reach 91-98% that of original TC17 wrought material; with the optimal parameters (1000 W-25 V-8 mm/s), the microhardness of the additive zone, the heat-affected zone and base material is evenly distributed at 370-390 HV500. The element content difference between the additive zone and base material is less than ±0.15%. Due to the existence of the pores 10 μm in diameter, the relative density could reach 99%, which is mainly inversely proportional to the powder feeding speed. The repaired zone is typically columnar and dendrite crystal, and the 0.5-1.5 mm-deep heat-affected zone in the groove interface is coarse equiaxial crystal.

  5. Tensile and impact behaviour of sinter-forged Cr, Ni and Mo alloyed powder metallurgy steels

    International Nuclear Information System (INIS)

    Sintered and forged low-alloy P/M steels containing Cr, Ni and Mo were subjected to tensile, hardness and impact tests, in order to understand the influence of the alloying elements and microstructure on their mechanical properties. Elemental powders of atomized iron, graphite, chromium, nickel and molybdenum were mixed in suitable proportions using a ball mill, compacted and sintered in order to yield the following alloy compositions: Fe-0.2%C, Fe-0.2%C-1%Cr, Fe-0.2%C-1%Cr-2%Ni, Fe-0.2%C-2%Ni and Fe-0.2%C-2%Ni-1.5%Mo. Cylindrical compacts of 24 mm diameter and 32 mm height were prepared from the powder mixes in a 1000 kN hydraulic press using suitable cylindrical die-punch combination. Sintering of the ceramic-coated cylindrical preforms was carried out at 1000 ± 10 oC in a muffle furnace for a period of 120 min. Immediately after sintering, the cylindrical compacts were hot upset forged and drawn into square cross-section bars of density values to near-theoretical using a 2000 kN friction screw press. The size of the bars was maintained as 10 x 10 x 110 mm for preparing tensile specimen and 12 x 12 x 70 mm for impact specimen. Standard tensile and impact specimens were machined off from the forged square rods. Standard procedure was followed for conducting tensile test and impact test on the forged alloys. Hardness of the hot forged alloys was also measured using Rockwell hardness tester. Microstructures of the alloys were examined for correlating with the mechanical properties. Fractographs of the fractured surfaces of the tensile specimens were obtained using a scanning electron microscope. From the present study, it is contended that the alloying elements Cr, Ni and Mo have strong influence on the tensile and impact properties of the low-alloy steels studied. Among all the five alloys considered, the steel with chromium addition has exhibited the highest tensile strength with the corresponding impact strength being the least. The same alloy has also been

  6. Titanium nanostructures for biomedical applications

    International Nuclear Information System (INIS)

    Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO2) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO2 nanotubes in cell interactions is based on the fact that TiO2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties. (topical review)

  7. Titanium nanostructures for biomedical applications

    Science.gov (United States)

    Kulkarni, M.; Mazare, A.; Gongadze, E.; Perutkova, Š.; Kralj-Iglič, V.; Milošev, I.; Schmuki, P.; Iglič, A.; Mozetič, M.

    2015-02-01

    Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO2) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO2 nanotubes in cell interactions is based on the fact that TiO2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties.

  8. Experimental Study and Numerical Simulation of the Casting-Forging Complex Near Net Forming of Alternator Claw-pole

    Institute of Scientific and Technical Information of China (English)

    J.L.Song; D.J.Hu; Q.C.Wang; H.Q.Chen; H.G.Guo

    2004-01-01

    As a newly developed precision technology, casting-forging complex near net forming process is utilized to produce complex components with a short lead time, low cost and high precision, thus to accelerate the response speed of the market and enhance the competitive power of products. In this paper, the casting-forging complex near net forming process of alternator claw pole was developed and investigated with a combination of experimental and numerical simulation method. Qualified near net workpiece was manufactured, mechanical parameter and relative field information during the forming process was also obtained. While the alternator claw-pole is processed with this technology, the forming force is small, the process is short and the quality of forgings is perfect. Therefore, the complex casting-forging near net forming process of claw-pole is an energy and material saving technology, which will have a vast developing and application prospect in the future.

  9. Fabrication and densification enhancement of SiC-particulate-reinforced copper matrix composites prepared via the sinter-forging process

    Institute of Scientific and Technical Information of China (English)

    Mohammadmehdi Shabani; Mohammad Hossein Paydar; Mohammad Mohsen Moshksar

    2014-01-01

    The fabrication of copper (Cu) and copper matrix silicon carbide (Cu/SiCp) particulate composites via the sinter-forging process was investigated. Sintering and sinter-forging processes were performed under an inert Ar atmosphere. The influence of sinter-forging time, tempera-ture, and compressive stress on the relative density and hardness of the prepared samples was systematically investigated and subsequently com-pared with that of the samples prepared by the conventional sintering process. The relative density and hardness of the composites were enhanced when they were prepared by the sinter-forging process. The relative density values of all Cu/SiCp composite samples were observed to decrease with the increase in SiC content.

  10. Production of titanium dioxide

    International Nuclear Information System (INIS)

    Titanium dioxide pigments provide whiteness and opacity to a vast range of everyday products from coatings and plastics to inks and even cosmetics and food. Manufacturing takes place using two different processes - the so called 'sulphate' and 'chloride' routes - to produce more than 4.5 million t per year worldwide. Both routes start from impure TiO2 based feedstocks containing moderately enhanced concentrations of radionuclides of natural origin. Experts from the TiO2 production industry and feedstock suppliers are assisting the IAEA in the development of a Safety Report concerning exposure to NORM within the TiO2 industry. The data assessment shows that, for both process routes, most of the radioactivity reports to the solid process wastes and there are no areas of concern related to products, co-products or liquid or gaseous effluents for production units operating to current environmental standards. Risk assessments for the landfill disposal of solid process waste similarly did not indicate any areas of concern where current waste management practices were followed. Process deposits, typically scale material, can exhibit enhanced activity concentrations of radium. Specific management practices such as controlled vessel entry to restrict worker exposure to these materials may be necessary. With such measures, it is considered unlikely that a worker would receive an annual effective dose exceeding 1 mSv. (author)

  11. 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%.

  12. Influence of Heat Treatment on Residual Stress in Cold-Forged Parts

    Directory of Open Access Journals (Sweden)

    Frederico Ozanan Neves

    2014-01-01

    Full Text Available Residual stresses are those stresses that remain in a body when there is no external load applied. Numerous factors can induce residual stresses in the material, including cold forming. Thermal treatments of steel are widely used because they can improve the mechanical properties of the steel, such as toughness, tenacity, and resistance; however, thermal treatments can also produce residual stresses. This study aims to analyze the residual stresses present in a cold-forged part after heat treatments. Half-cylinder samples of AISI 1045 steel were cold-forged, and a wedge tool was pressed into their surface, causing a strain gradient. The samples were then heat-treated by annealing, normalizing, quenching, or quenching and tempering. A numerical simulation was also performed to aid in choosing the measurement points in the samples. The results show that residual stresses are dependent on the heat treatment and on the intensity and nature of previous residual stresses in the body.

  13. Structure of magnesium alloy MA14 after multistep isothermal forging and subsequent isothermal rolling

    Science.gov (United States)

    Nugmanov, D. R.; Sitdikov, O. Sh.; Markushev, M. V.

    2015-10-01

    Optical metallography and electron microscopy have been used to analyze the structural changes in magnesium MA14 alloy subjected to processing that combines multistep isothermal forging and isothermal rolling. It has been found that forging of a bulk workpiece leads to the formation of a structure, 85-90% of which consists of recrystallized grains with an average size of less than 5 µm. Subsequent rolling results in a completely recrystallized structure with a grain size of 1-2 µm. It is shown that the resultant structural states are characterized by grain size nonuniformity inherited from the initial hot-pressed semi-finished product. The nature and features of crystallization processes that take place in the alloy during processing are discussed.

  14. A New Cold Rotary Forging Technology for Automotive Starter Guiding Cylinder with Internal Helical Involute Spline

    Directory of Open Access Journals (Sweden)

    Wang Ping

    2016-01-01

    Full Text Available A new cold rotary forging technology of the internal helical involute spline was presented based on an analysis of the structure of automotive starter guide cylinder. 3D rigid-plastic finite element model was employed. Billet deformation, Billet equivalent stress and forming load were investigated under the DEFORM 3D software environment, then the forming process parameters were applied in the forming trials, and the simulation results are conformed with the experimental results. The validity of 3D finite element simulation model has been verified. The research results show that the proposed cold rotary forging technology can be efficient in handling of the forming manufacturing problems of automobile starter guide cylinder with internal helical involute spline.

  15. 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.

  16. Effect of interfacial friction during forging of solid powder discs of large slenderness ratio

    Indian Academy of Sciences (India)

    R K Ranjan; S Kumar

    2004-10-01

    The paper reports an investigation into the effect of interfacial friction law during the forging of a powder circular disc with large slenderness ratio (L/D) between two flat dies. The deformation pattern during the operation is influenced by many factors, which interact with each other in a complex manner. The relative velocity between the work piece material and the die surface, together with high interfacial pressure and/or deformation modes, creates the conditions essential for adhesion in addition to sliding. The decisive factors are the interfacial conditions, initial relative density of the preform and geometry of the preform. An attempt has been made to determine the most realistic interfacial friction law and die pressures developed during such forging using an upper bound approach. The results so obtained are presented graphically and discussed critically to illustrate the interaction of various interfacial friction laws involved.

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

    International Nuclear Information System (INIS)

    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%

  18. Fiber reinforced titanium alloy composites

    International Nuclear Information System (INIS)

    The more important titanium matrix composites studied to date are composed of titanium alloy matrices, such as Ti 6Al--4V, reinforced with filaments of boron, silicon carbide, or sapphire, as well as with wires of beryllium or refractory metal alloys. The primary fabrication techniques for these materials involve vacuum hot pressing at 1300 to 16000F, alternate layers of titanium alloy matrix foils, and suitably aligned filament mats. The more ductile reinforcements such as beryllium, have been incorporated into titanium matrix composites by coextrusion. Fabrication of composite gas turbine engine fan blades from both boron (SiC coated) and beryllium reinforced Ti 6Al--4V alloy is described. Feasibility studies have been made in the fabrication of Boron/Ti 6Al--4V composite rings for possible gas turbine engine disc applications. Mechanical properties of various titanium matrix composite systems are presented and demonstrate the attractive elevated temperature properties of some systems to 10000F. (35 fig, 6 tables) (U.S.)

  19. Effect of isothermal forging on microstructure and fatigue behavior of blended elemental Ti-6Al-4V powder compacts

    Science.gov (United States)

    Weiss, I.; Eylon, D.; Toaz, M. W.; Froes, F. H.

    1986-03-01

    The effect of isothermal hot forging (IHF) on microstructure, pore closure, and tensile and fatigue properties of Ti-6A1-4V blended elemental cold pressed and sintered powder compacts was investigated. Two types of sponge fines were used: (a) high chloride produced by the Hunter sodium reduction process (HP) and (b) low chloride produced by the electrolytic process (EP). The as-sintered HP compacts were 99 pct dense while the EP compacts were only 92 pct dense. All sintered preforms were isothermally hot forged below the beta transus temperature and reached almost full density. The microstructure of the HP forged compacts consisted of fine equiaxed alpha, while the EP forged compacts exhibited a coarse lenticular alpha structure after 30 pct reduction and a partially recrystallized structure after 68 pct reduction. It was found that EP compacts forged to a 30 pct reduction exhibited a low fatigue limit of 172 MPa (25 ksi), since the lenticular alpha morphology and the residual porosity resulted in premature fatigue crack initiation. On the other hand, a higher fatigue strength of 485 MPa (70 ksi) was obtained for EP compacts forged to a 78 pct reduction due to the mixed equiaxed/lenticular alpha morphology as well as removal of stress concentration features such as interparticle pore interfaces.

  20. Thermal Forge Welding Simulations: A Weldability Study of X65 Pipeline Quality

    OpenAIRE

    Herikstad, Ruth Oftedal

    2011-01-01

    Shield active gas forge welding is a time-efficient welding technique for solid statewelding of pipelines. Pipes are first heated by induction or ohmic resistance, and areforged together using an active shielding gas to reduce surface oxides. The solid statewelding requires lower peak temperatures than fusion welding, reducing the graingrowth. The low peak temperature also makes this technique possible on oil rigs andvessels where the explosion risk is high. The cooling of the pipes after wel...

  1. Implementation of the finite deformation plastic theory-Tensor derivative and metal forging simulation

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    It has been shown that the traditional small deformation plasticity can be transplanted to the finite deformation plasticity by using the logarithmic strain measure only. In this way, the mathematical problem of how to find the derivative of a tensor function arises. In this paper, a general method for finding the derivative of a tensor function is proposed. Several metal forging examples are given.During the calculation, the mesh regeneration is not even invoked.

  2. Influence of Heat Treatment on Residual Stress in Cold-Forged Parts

    OpenAIRE

    Frederico Ozanan Neves; Thiago Luis Lara Oliviera; Durval Uchoas Braga; Alex Sander Chaves da Silva

    2014-01-01

    Residual stresses are those stresses that remain in a body when there is no external load applied. Numerous factors can induce residual stresses in the material, including cold forming. Thermal treatments of steel are widely used because they can improve the mechanical properties of the steel, such as toughness, tenacity, and resistance; however, thermal treatments can also produce residual stresses. This study aims to analyze the residual stresses present in a cold-forged part after heat tre...

  3. Comparative analysis of wear mechanism of different types of forging dies

    OpenAIRE

    A. Mazurkiewicz; Smolik, J.

    2011-01-01

    Purpose: Hot working dies are influenced by three main factors causing their destruction: the cyclically changeable mechanical loads, intensive thermal shocks, as well as intensive friction, and erosion. The great variety of the shapes of forgings, the material they are made of (carbon steel, alloy steel, brass) and the precision of their production – whether they are supposed to undergo further treatment or are considered to be the final products – result in a variety of problems encountered...

  4. Thixo forging process of wrought aluminum alloy fabricated by rotational helical shape stirrer

    International Nuclear Information System (INIS)

    The manufacture of rheology materials from wrought and casting aluminum alloys using controlling solid fraction and crystal grain is demonstrated in this paper. The equipment to form the rheology material was designed so that shear force and applied pressure could be carefully and simultaneously applied using a mechanical stirrer. The problems caused by using this method with the thixo forging process were studied by investigating the mechanical properties of a sample that had a controlled solid fraction of 45-50 %

  5. Finite element simulation of the tool steel stress response as used in a hot forging

    International Nuclear Information System (INIS)

    Hot-work forging tools are subjected to severe and complex loading conditions (cyclic stress/strain conditions, varying strain rates, varying temperature, environmental damage), leading to short die life. There is also a temperature and time dependant material response to consider. Presently, hot-forging of a steel crankshaft is approached by a combined experimental and numerical simulation study of a hot-work tool steel.The forging conditions were investigated by thermal measurements and damage analysis. Laboratory testing by isothermal fatigue in the temperature range 200-600 deg. C was performed. An elasto-plastic kinematic and isotropic hardening model (according to Chaboche) was used to model the material behaviour where the material parameters were derived from the experimental part. Viscoplastic effects are not accounted for in the material model as they have minor influence on the stress-strain relation in the experimental setup. The model was implemented in a FEM program (MSC.Marc) using a semi-implicit time integration scheme according to Shih and Ortiz, and evaluated by modelling of the isothermal fatigue tests.The FE-results managed to describe the materials general behavior, the correlation between the experimental simulated values were however not satisfactory due to influence of factors in the parameter derivation. Important features of the material behaviour are the cyclic softening and its dependence of the temperature, and also the strain path history. The long-term goal is to fully analyze the hot-forging die in service by numerical simulation and to study the influence of manufacturing processes on die properties

  6. Research on Simulation of Giant Forging Hydraulic Press Decoupling Control for Synchronous Control System

    OpenAIRE

    Xinliang Liu; Yingjian Deng; Zhongwei Liu

    2013-01-01

    A giant forging hydraulic press active synchronous control system is a mutually-coupled multi-input and multi-output system. To solve the elimination of the multi-channel interference, a multiple-input and multiple-output mathematical model center on active-beam is established; multi-channel synchronous decoupling control strategy is studied. The simulation results show that: the system eliminates the role of strong interference between multi-channel accesses to very good inhibitory effect of...

  7. Parallel investigation of double forged pure tungsten samples irradiated in three DPF devices

    Energy Technology Data Exchange (ETDEWEB)

    Gribkov, V.A. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); A.A. Baikov Institute of Metallurgy and Material Science RAS, Moscow (Russian Federation); A. Salam International Centre for Theoretical Physics, Trieste (Italy); Paduch, M.; Zielinska, E. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Laas, T. [Institute of Mathematics and Natural Sciences, Tallinn University, Tallinn (Estonia); Shirokova, V., E-mail: veroonika.pelohh@gmail.com [Institute of Mathematics and Natural Sciences, Tallinn University, Tallinn (Estonia); Väli, B.; Paju, J. [Institute of Mathematics and Natural Sciences, Tallinn University, Tallinn (Estonia); Pimenov, V.N.; Demina, E.V.; Latyshev, S.V. [A.A. Baikov Institute of Metallurgy and Material Science RAS, Moscow (Russian Federation); Niemela, J.; Crespo, M.-L.; Cicuttin, A. [A. Salam International Centre for Theoretical Physics, Trieste (Italy); Talab, A.A. [Atomic Energy Authority, NRC, Plasma Physics and Nuclear Fusion Department (Egypt); Pokatilov, A.; Parker, M. [AS Metrosert, Central Office of Metrology, Tallinn (Estonia); Tallinn University of Technology, Tallinn (Estonia)

    2015-08-15

    The double forged pure tungsten (W) samples (supplied by IAEA CRP from the FZJ team in Juelich, Germany) were irradiated in DPF (dense plasma focus) devices PF-12, “Bora” and PF-1000 by hot plasma and fast ion streams. We have used the following analytical methods: microscopy (optical and scanning electron), X-ray photoelectron spectroscopy, electrical conductivity and microroughness measurements. The damage dependence of the tungsten grades on irradiation conditions and power flux densities of irradiation processes is discussed.

  8. Parallel investigation of double forged pure tungsten samples irradiated in three DPF devices

    Science.gov (United States)

    Gribkov, V. A.; Paduch, M.; Zielinska, E.; Laas, T.; Shirokova, V.; Väli, B.; Paju, J.; Pimenov, V. N.; Demina, E. V.; Latyshev, S. V.; Niemela, J.; Crespo, M.-L.; Cicuttin, A.; Talab, A. A.; Pokatilov, A.; Parker, M.

    2015-08-01

    The double forged pure tungsten (W) samples (supplied by IAEA CRP from the FZJ team in Juelich, Germany) were irradiated in DPF (dense plasma focus) devices PF-12, "Bora" and PF-1000 by hot plasma and fast ion streams. We have used the following analytical methods: microscopy (optical and scanning electron), X-ray photoelectron spectroscopy, electrical conductivity and microroughness measurements. The damage dependence of the tungsten grades on irradiation conditions and power flux densities of irradiation processes is discussed.

  9. Heat treatment of cold formed steel forgings for the automotive industry

    OpenAIRE

    B. Kosec; M. Brezigar; G. Kosec; J. Bernetic; M. Bizjak

    2007-01-01

    Purpose: In the Slovenian company ISKRA Avtoelektrika they manufacture, with the processes of cold forming, a great number of a different steel forgings for the Slovenian and European automotive industry. During their exploitation they are exposed to the high mechanical and temperature loads.Design/methodology/approach: A gas furnaces and devices play important role in the heat treatments of various metal parts for the automotive industry. Their thermotechnical characteristics have a great in...

  10. Heat treatment of cold formed steel forgings for the automotive industry

    Directory of Open Access Journals (Sweden)

    B. Kosec

    2007-06-01

    Full Text Available Purpose: In the Slovenian company ISKRA Avtoelektrika they manufacture, with the processes of cold forming, a great number of a different steel forgings for the Slovenian and European automotive industry. During their exploitation they are exposed to the high mechanical and temperature loads.Design/methodology/approach: A gas furnaces and devices play important role in the heat treatments of various metal parts for the automotive industry. Their thermotechnical characteristics have a great influence on the product quality and costs. The basic aim of our investigation work is to present the optimization of a device with emphasis on continuous control of working temperature.Findings: The efficiency and quality of the treatment were analysed with the use of: chemical analysis, hardness measurements, measurements of carbon and sulphur content in the surface layer, and metallographic examination methods.Research limitations/implications: For economical production of cold formed steel forgings for the automotive industry it is important that they have a long working life. The corresponding mechanical and thermal properties of the steel forgings are achieved by a heat treatment.Practical implications: As a practical example is presented an optimisation of the heat treatment procedure for typical cold formed steel forging for the automotive industry from the ISKRA Avtoelektrika production program. The practical result of the used heat treatment are the cold formed steel pinions with the surface hardness of approximately 65 HRC, and the case hardened depth of the surface layer approximately 0.7 mm.Originality/value: On the basis of the results of our technical investigation work and corresponding economical studies, the second device (of the same producer, type and capacity for the heat treatment was installed at the end of last year.

  11. Design of Controlled Processing Conditions for Drop Forgings Made of Microalloy Steel Grades for Mining Industry

    OpenAIRE

    Skubisz P.; Żak A.; Burdek M.; Lisiecki Ł.; Micek P.

    2015-01-01

    Effect of plastic processing and controlled cooling on microstructure and mechanical properties of experimental steel grades with microalloyed with Ti, V and/or Nb, varying in the content of Mo is presented as an offer for mining industry for replacement traditionally heat-treatable hardenability grades. The goal of the work is producing microstructure condition, which after controlled hot forging and direct heat treatment, involving quenching and self-tempering, are meant to provide good com...

  12. University hosts symposium to forge agenda for financial regulatory reform; transparency cited as major challenge

    OpenAIRE

    Micale, Barbara L.

    2009-01-01

    Virginia Tech National Capital Region recently hosted a symposium titled "A Public Administration Moment: Forging an Agenda for Financial Regulatory Reform" to address such relevant topics as: How can financial regulation be made more transparent? What is the government's role in regulating financial innovation and risk? What are the educational challenges in preparing public administrators for financial regulation? And what are the lessons from rapid responses to tough economic issues?

  13. Heat transfer coefficient for F.E analysis in the warm forging process

    OpenAIRE

    Kang, S S; Kang, J. H.; Lee, K. O.

    2007-01-01

    Purpose: The Purpose of this paper is to obtain suitable convection and contact heat transfer coefficient forone-time finite element analysis in the warm forging process.Design/methodology/approach: To do this, the temperature of the tool used in the operation was measured witha thermocouple and repeated finite element analysis(FEA) was performed using the experimentally calculatedcontact and cooling heat transfer coefficient. Also the surface temperature of the active tool was obtained bycom...

  14. Parallel investigation of double forged pure tungsten samples irradiated in three DPF devices

    International Nuclear Information System (INIS)

    The double forged pure tungsten (W) samples (supplied by IAEA CRP from the FZJ team in Juelich, Germany) were irradiated in DPF (dense plasma focus) devices PF-12, “Bora” and PF-1000 by hot plasma and fast ion streams. We have used the following analytical methods: microscopy (optical and scanning electron), X-ray photoelectron spectroscopy, electrical conductivity and microroughness measurements. The damage dependence of the tungsten grades on irradiation conditions and power flux densities of irradiation processes is discussed

  15. Lightweight Protective Coatings For Titanium Alloys

    Science.gov (United States)

    Wiedemann, Karl E.; Taylor, Patrick J.; Clark, Ronald K.

    1992-01-01

    Lightweight coating developed to protect titanium and titanium aluminide alloys and titanium-matrix composite materials from attack by environment when used at high temperatures. Applied by sol-gel methods, and thickness less than 5 micrometers. Reaction-barrier and self-healing diffusion-barrier layers combine to protect titanium alloy against chemical attack by oxygen and nitrogen at high temperatures with very promising results. Can be extended to protection of other environmentally sensitive materials.

  16. Titanium, Sinusitis, and the Yellow Nail Syndrome

    OpenAIRE

    Berglund, Fredrik; Carlmark, Björn

    2010-01-01

    Yellow nail syndrome is characterized by nail changes, respiratory disorders, and lymphedema. In a yellow nail patient with a skeletal titanium implant and with gold in her teeth, we found high levels of titanium in nail clippings. This study aims to examine the possible role of titanium in the genesis of the yellow nail syndrome. Nail clippings from patients with one or more features of the yellow nail syndrome were analyzed by energy dispersive X-ray fluorescence. Titanium was regularly fou...

  17. 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.

  18. Heat transfer coefficient for F.E analysis in the warm forging process

    Directory of Open Access Journals (Sweden)

    S.S. Kang

    2007-01-01

    Full Text Available Purpose: The Purpose of this paper is to obtain suitable convection and contact heat transfer coefficient forone-time finite element analysis in the warm forging process.Design/methodology/approach: To do this, the temperature of the tool used in the operation was measured witha thermocouple and repeated finite element analysis(FEA was performed using the experimentally calculatedcontact and cooling heat transfer coefficient. Also the surface temperature of the active tool was obtained bycomparing the measurement and analysis results and finally the contact heat transfer coefficient for one-time FEAwas completed by comparing the surface temperature between the repeated FEA and one-time FEA results.Findings: The acceptable convection heat transfer coefficients are from 0.3 to 0.8N/mm/s/K and the contactheat transfer coefficient of 6~9N/mm/s/K is appropriate for the warm forging process with flow-typelubrication conditions.Practical implications: A comparison of the temperatures from the repeated and one-time analysis allows anoptimum contact heat transfer coefficient for the one time finite element analysis to be determined.Originality/value: Several studies have been conducted with different conditions such as applied pressure andkind of lubricant, but no research has been conducted concerning the convection heat transfer coefficient in thewarm forging process. Also, comparative analysis concerning the reason for difference between experimentallydetermined contact heat transfer coefficient and practically adapted one has not been conducted, yet.

  19. 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.

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

    Directory of Open Access Journals (Sweden)

    Shao-Yi Hsia

    2015-09-01

    Full Text Available 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.

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

    International Nuclear Information System (INIS)

    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.

  2. Experimental and Numerical Investigation of Forging Process to Reproduce a 3D Aluminium Foam Complex Shape

    International Nuclear Information System (INIS)

    Metallic foams represent one of the most exciting materials introduced in the manufacturing scenario in the last years. In the study here addressed, the experimental and numerical investigations on the forging process of a simple foam billet shaped into complex sculptured parts were carried out. In particular, the deformation behavior of metallic foams and the development of density gradients were investigated through a series of experimental forging tests in order to produce a selected portion of a hip prosthesis. The human bone replacement was chosen as case study due to its industrial demand and for its particular 3D complex shape. A finite element code (Deform 3D) was utilized for modeling the foam behavior during the forging process and an accurate material rheology description was used based on a porous material model which includes the measured local density. Once the effectiveness of the utilized Finite Element model was verified through the comparison with the experimental evidences, a numerical study of the influence of the foam density was investigated. The obtained numerical results shown as the initial billet density plays an important role on the prediction of the final shape, the optimization of the flash as well as the estimation of the punch load

  3. Simulations and Experiments of the Nonisothermal Forging Process of a Ti-6Al-4V Impeller

    Science.gov (United States)

    Prabhu, T. Ram

    2016-06-01

    In the present study, a nonisothermal precision forging process of a Ti-6Al-4V first-stage impeller for the gas turbine engine was simulated using the finite element software. The simulation results such as load requirements, damage, velocity field, stress, strain, and temperature distributions are discussed in detail. Simulations predicted the maximum load requirement of about 80 MN. The maximum temperature loss was observed at the contour surface regions. The center and contour regions are the high-strained regions in the part. To validate the model, forging experiments mimicking simulations were performed in the α + β phases region (930 °C). The selected locations of the part were characterized for tensile properties at 27 and 200 °C, hardness, microstructure, grain size, and the amount of primary α phase based on the strain distribution results. The soundness of the forged part was verified using fluorescent penetrant test (Mil Std 2175 Grade A) and ultrasonic test (AMS 2630 class A1). From the experimental results, it was found that the variations in the hardness, tensile properties at room, and elevated temperature are not significant. The microstructure, grain size, and primary α phase content are nearly same.

  4. Current forgings and their properties for steam generator of nuclear plant

    International Nuclear Information System (INIS)

    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

  5. Effects of Forging Process Parameters on Microstructure Evolution of Aluminum Alloy 7050

    International Nuclear Information System (INIS)

    The objective of this work is to investigate the behavior of microstructure evolution of aluminum alloy 7050 under the condition of different forging process parameters by means of combining materials physical model with finite element code. For the purpose of establishing constitutive equation and physical model of microstructure evolution, the isothermal compression test were performed by machine Gleeble 1500 on the condition of temperatures ranging from 250 deg. C to 450 deg. C and constant strain rates of 0.01s-1, 0.1s-1, 1s-1 and 10s-1. The behaviors of microstructure evolutions of aluminum alloy 7050 under difference process parameters were studied by metallographic observations. The experiment results showed that recrystallization during forming process occurred at the critical strain and the volume fraction of recrystallization changed with the temperature and strain rate. According to the results of isothermal compression test, a constitutive equation and an empirical model of DRX were obtained. A finite element code DEFORM 3D was used to analyze the influence of different forging process parameters on the behavior of microstructure evolution in details. The present model and simulation method can be served as a useful tool to predict and control the properties and shape of aluminum alloy 7050 components during forging

  6. Adaptive mesh refinement in titanium

    Energy Technology Data Exchange (ETDEWEB)

    Colella, Phillip; Wen, Tong

    2005-01-21

    In this paper, we evaluate Titanium's usability as a high-level parallel programming language through a case study, where we implement a subset of Chombo's functionality in Titanium. Chombo is a software package applying the Adaptive Mesh Refinement methodology to numerical Partial Differential Equations at the production level. In Chombo, the library approach is used to parallel programming (C++ and Fortran, with MPI), whereas Titanium is a Java dialect designed for high-performance scientific computing. The performance of our implementation is studied and compared with that of Chombo in solving Poisson's equation based on two grid configurations from a real application. Also provided are the counts of lines of code from both sides.

  7. Photonuclear reactions on titanium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Belyshev, S. S. [Moscow State University (Russian Federation); Dzhilavyan, L. Z. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Ishkhanov, B. S.; Kapitonov, I. M. [Moscow State University (Russian Federation); Kuznetsov, A. A., E-mail: kuznets@depni.sinp.msu.ru; Orlin, V. N.; Stopani, K. A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

    2015-03-15

    The photodisintegration of titanium isotopes in the giant-dipole-resonance energy region is studied by the photon-activation method. Bremsstrahlung photons whose spectrum has the endpoint energy of 55 MeV is used. The yields and integrated cross sections are determined for photoproton reactions on the titanium isotopes {sup 47,48,49,50}Ti. The respective experimental results are compared with their counterparts calculated on the basis of the TALYS code and a combined photonucleon-reaction model. The TALYS code disregards the isospin structure of the giant dipole resonance and is therefore unable to describe the yield of photoproton reactions on the heavy titanium isotopes {sup 49,50}Ti.

  8. Mechanical properties of titanium connectors.

    Science.gov (United States)

    Neo, T K; Chai, J; Gilbert, J L; Wozniak, W T; Engelman, M J

    1996-01-01

    The tensile mechanical properties of welded titanium joints were studied, and intact titanium was used as controls. Welded joints were fabricated with either a stereographic laser-welding technique or a gas tungsten arc welding technique. The effect of heat treatment following a simulated porcelain application was also investigated. Heat-treated laser welds had significantly lower ultimate tensile strengths. Heat treatment had no effect on the modulus of elasticity or elongation, but generally significantly decreased the yield strength of the titanium specimens. The gas tungsten are welding specimens had significantly higher yield strengths and elastic moduli than the other two groups. The elongation of the control specimens was significantly greater than the elongation of the gas tungsten arc welding specimens, which was in turn significantly higher than that of the laser-welded specimens. PMID:8957877

  9. 21 CFR 73.575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.575 Section 73.575 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.575 Titanium dioxide. (a) Identity. (1) The color additive titanium dioxide is synthetically...

  10. 21 CFR 73.2575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  11. 21 CFR 73.1575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide...

  12. 21 CFR 73.3126 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium...

  13. 40 CFR 180.1195 - Titanium dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or...

  14. Effect of whitening toothpaste on titanium and titanium alloy surfaces

    Directory of Open Access Journals (Sweden)

    Adriana Cláudia Lapria Faria

    2012-12-01

    Full Text Available Dental implants have increased the use of titanium and titanium alloys in prosthetic applications. Whitening toothpastes with peroxides are available for patients with high aesthetic requirements, but the effect of whitening toothpastes on titanium surfaces is not yet known, although titanium is prone to fluoride ion attack. Thus, the aim of the present study was to compare Ti-5Ta alloy to cp Ti after toothbrushing with whitening and conventional toothpastes. Ti-5Ta (%wt alloy was melted in an arc melting furnace and compared with cp Ti. Disks and toothbrush heads were embedded in PVC rings to be mounted onto a toothbrushing test apparatus. A total of 260,000 cycles were carried out at 250 cycles/minute under a load of 5 N on samples immersed in toothpaste slurries. Surface roughness and Vickers microhardness were evaluated before and after toothbrushing. One sample of each material/toothpaste was analyzed by Scanning Electron Microscopy (SEM and compared with a sample that had not been submitted to toothbrushing. Surface roughness increased significantly after toothbrushing, but no differences were noted after toothbrushing with different toothpastes. Toothbrushing did not significantly affect sample microhardness. The results suggest that toothpastes that contain and those that do not contain peroxides in their composition have different effects on cp Ti and Ti-5Ta surfaces. Although no significant difference was noted in the microhardness and roughness of the surfaces brushed with different toothpastes, both toothpastes increased roughness after toothbrushing.

  15. The use of a modular titanium endoprosthesis in skeletal reconstructions after bone tumor resections: method presentation and analysis of 37 cases

    Directory of Open Access Journals (Sweden)

    Croci Alberto Tesconi

    2000-01-01

    Full Text Available We analyzed 37 patients who underwent segmental wide resection of bone tumors and reconstruction with a modular titanium endoprosthesis at the Orthopaedic Oncology Group, between 1992 and 1998. Twelve patients were male and 25 were female, with a mean age of 30 years (9 - 81. The mean follow-up was 14 months (2 - 48. The diagnoses were: osteosarcoma (14 cases, metastatic carcinoma (10, Ewing's sarcoma (4, giant cell tumor (4, malignant fibrous histiocytoma (3, chondrosarcoma (1, and aneurysmal bone cyst (1. Eleven articulated total knee, 8 partial proximal femur with bipolar acetabulum, 8 partial proximal humerus, 3 total femur, 2 partial proximal tibia, 2 diaphyseal femur, 2 diaphyseal humerus, and 1 total proximal femur with cementless acetabulum endoprosthesis implant procedures were done. The complications related to the procedure included: infection (5 cases, dislocation (3, module loosening (1, and ulnar nerve paresthesia (1. We used the following criteria for the clinical evaluation: presence of pain, range of motion, reconstruction stability, surgical and oncologic complications, and patient acceptance. The results were good in 56.8% of the cases, regular in 32.4% and poor in 10.8%.

  16. Rifampicin-fosfomycin coating for cementless endoprostheses: antimicrobial effects against methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA).

    Science.gov (United States)

    Alt, Volker; Kirchhof, Kristin; Seim, Florian; Hrubesch, Isabelle; Lips, Katrin S; Mannel, Henrich; Domann, Eugen; Schnettler, Reinhard

    2014-10-01

    New strategies to decrease infection rates in cementless arthroplasty are needed, especially in the context of the growing incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections. The purpose of this study was to investigate the antimicrobial activity of a rifampicin-fosfomycin coating against methicillin-sensitive Staphylococcus aureus (MSSA) and MRSA in a rabbit infection prophylaxis model. Uncoated or rifampicin-fosfomycin-coated K-wires were inserted into the intramedullary canal of the tibia in rabbits and contaminated with an inoculation dose of 10(5) or 10(6) colony-forming units of MSSA EDCC 5055 in study 1 and MRSA T6625930 in study 2, respectively. After 28days the animals were killed and clinical, histological and microbiological assessment, including pulse-field gel electrophoresis, was conducted. Positive culture growth in agar plate testing and/or clinical signs and/or histological signs were defined positive for infection. Statistical evaluation was performed using Fisher's exact test. Both studies showed a statistically significant reduction of infection rates for rifampicin-fosfomycin-coated implants compared to uncoated K-wires (P=0.015). In both studies none of the 12 animals that were treated with a rifampicin-fosfomycin-coated implant showed clinical signs of infection or a positive agar plate testing result. In both studies, one animal of the coating group showed the presence of sporadic bacteria with concomitant inflammatory signs in histology. The control groups in both studies exhibited an infection rate of 100% with clear clinical signs of infection and positive culture growth in all animals. In summary, the rifampicin-fosfomycin-coating showed excellent antimicrobial activity against both MSSA and MRSA, and therefore warrants further clinical testing. PMID:24948548

  17. Estudo da estabilidade dos componentes na artroplastia total do joelho sem cimento Study on implant stability in cementless total knee arthroplasty

    Directory of Open Access Journals (Sweden)

    Luís Eduardo Passarelli Tírico

    2012-01-01

    Full Text Available OBJETIVO: Comparar dois métodos de avaliação da estabilidade dos componentes tibial e femoral nas artroplastias de joelho não cimentadas com plataforma rotatória. MÉTODOS: Para isso foram avaliados 20 pacientes (20 joelhos através de uma análise de radiografias dinâmicas com intensificador de imagem e manobras de estresse em varo e valgo, que foram comparadas com radiografias estáticas em frente e perfil dos joelhos, analisadas por dois cirurgiões experientes, cegos um em relação ao outro. RESULTADOS: Os resultados das análises estáticas e dinâmicas foram comparados e demonstraram forte correlação estatística (pObjetives: Determine the stability of tibial and femoral components of 20 cementless knee arthroplasties with rotating platform. METHODS: The 20 patients (20 knees underwent an analysis of dynamic radiographs with an image amplifier and maneuvers of varus and valgus which were compared to static frontal and lateral radiographs of the knees and analyzed by two experienced surgeons in a double-blind way. RESULTS: We could observe in this study that both methods showed very similar results for the stability of the tibial and femoral components (p<0,001 using the Kappa method for comparison. CONCLUSION: The tibial component was more unstable in relation to the femoral component in both static and dynamic studies. Level of evidence IV, Case Series.

  18. Titanium 1990: Products and applications; Proceedings of the International Conference, Buena Vista, FL, Sept. 30-Oct. 3, 1990. Vols. 1 and 2

    International Nuclear Information System (INIS)

    The present conference on Ti-based products and their applications discusses Ti alloy products and applications in China and the USSR, the use of IMI 834 in aircraft engines, Ti-6Al-4V forgings with enhanced fatigue resistance, hydrogen embrittlement of titanium aluminides, cold-rolled Ti alloy foils, Ti alloy multiwall structures, leading-edge erosion of large Ti alloy blades, a novel Cu-Fe-Ti alloy, anodization of Ti for space applications, Ti alloy property improvement via ion implantation, and Co-W-Ti alloy electroplating. Also discussed are the backbone-process fabrication of Ti heat-exchanger tubes, fiber-delivery laser welding of Ti alloy tubing, a novel low-alloy/high-strength Ti composition, the weldability of titanium aluminide, the casting of dental Ti crowns, isothermal forging of Ti-alloy surgical implants, high-speed heat treatment for Ti alloys, cold-roll extrusion of Ti-6Al-4V cylinders, temperature profiles in Ti sponge production, and the superplasticity of eutectoidally decomposed Ti alloys

  19. Synthesis and properties of nanoscale titanium boride

    Science.gov (United States)

    Efimova, K. A.; Galevskiy, G. V.; Rudneva, V. V.

    2015-09-01

    This work reports the scientific and technological grounds for plasma synthesis of titanium diboride, including thermodynamic and kinetic conditions of boride formation when titanium and titanium dioxide are interacting with products resulting from boron gasification in the nitrogen - hydrogen plasma flow, and two variations of its behavior using the powder mixtures: titanium - boron and titanium dioxide - boron. To study these technology variations, the mathematical models were derived, describing the relation between element contents in the synthesized products of titanium and free boron and basic parameters. The probable mechanism proposed for forming titanium diboride according to a "vapour - melt - crystal" pattern was examined, covering condensation of titanium vapour in the form of aerosol, boriding of nanoscale melt droplets by boron hydrides and crystallization of titanium - boron melt. The comprehensive physical - chemical certification of titanium diboride was carried out, including the study of its crystal structure, phase and chemical composition, dispersion, morphology and particle oxidation. Technological application prospects for use of titanium diboride nanoscale powder as constituent element in the wettable coating for carbon cathodes having excellent physical and mechanical performance and protective properties.

  20. Advances in cost effective processing of titanium

    International Nuclear Information System (INIS)

    Recently an industry expert pointed out that one of the greatest hindrances to the growth of titanium usage has been the low percentage of material usable in the final product. Due to the extensive processing, forming, and machining operations typically performed on titanium, yield losses are high. This is especially true in aerospace applications where most titanium is used. In engine components, the start to finish ratio, known as the buy to fly ratio, is often as high as 7 to 1. This can be illustrated by looking at the use of titanium in Pratt and Whitney engines. In the JT-8D-217 used on Boeing's 737-200, the titanium buyweight is 5,385 pounds, whereas the finished titanium, flyweight is just 758 pounds. This start to finish ratio is 7.1:1, giving titanium 17.0% of total engine weight. (orig.)

  1. Effect of boron additions and processing on microstructure and mechanical properties of a titanium alloy Ti–6.5Al–3.3Mo–0.3Si

    International Nuclear Information System (INIS)

    The effects of boron additions in an amount of 0.1–2 wt%, thermomechanical processing and heat treatment on microstructure and mechanical properties of a two-phase titanium alloy Ti–6.5Al–3.3Mo–0.3Si alloy have been investigated. Depending on the boron amount, the materials under study were divided into two groups: (1) boron modified alloys containing ~0.1 wt% of boron and (2) discontinuously reinforced metal matrix Ti–TiB based composites containing 1.5–2 wt% of boron. Boron additions led to formation of TiB whiskers, which were predominantly located along boundaries of prior β-grains and α-colonies resulting in refined as-cast microstructure. Multiple 3D forging at T=650–700 °C applied for the boron modified alloys resulted in formation of ultrafine-grained microstructure and intensive breaking of TiB whiskers. Tensile properties of the Ti–6.5Al–3.3Mo–0.3Si–0.2 wt% B alloy after multiple 3D forging followed by β-heat treatment were found to be appreciably higher than those of the alloy free of boron after the same processing route that was ascribed to better controlling the β-grain size during β heat treatment. The composite materials were subjected to multiple isothermal 2D forging at T=950 °C that provided effective alignment of TiB whiskers while retaining their high aspect ratio. The hot forged composites demonstrated appreciably higher strength, creep resistance in comparison with those of the base alloy without drastic reduction in ductility. The effect of TiB whiskers orientation and morphology on the tensile properties of the composite materials is discussed

  2. Nanodispersed boriding of titanium alloy

    International Nuclear Information System (INIS)

    The problem of improving the operational reliability of machines is becoming increasingly important due to the increased mechanical, thermal and other loads on the details. There are many surface hardening methods for machines parts which breakdown begins with surface corruption. The most promising methods are chemical-thermal treatment. The aim of this work is to study the impact of boriding on the structure and properties of titanium alloy. Materials and Methods: The material of this study is VT3-1 titanium alloy. The boriding were conducted using nanodispersed powder blend based on boric substances. It is established that boriding of paste compounds allows obtaining the surface hardness within 30 - 29 GPa and with declining to 27- 26 GPa in layer to the transition zone (with total thickness up to 110 μm) owing to changes of the layer phase composition where T2B, TiB, TiB2 titanium borides are formed. The increasing of chemical-thermal treatment time from 15 minutes to 2 hours leads to thickening of the borated layer (30 - 110 μm) and transition zone (30 - 190 μm). Due to usage of nanodispersed boric powder, the boriding duration is decreasing in 2 - 3 times. This allows saving time and electric energy. The developed optimal mode of boriding the VT3-1 titanium alloy allows obtaining the required operational characteristics and to combine the saturation of the surface layer with atomic boron and hardening

  3. Lactobacillusassisted synthesis of titanium nanoparticles

    Directory of Open Access Journals (Sweden)

    Jha Anal

    2007-01-01

    Full Text Available AbstractAn eco-friendlylactobacillussp. (microbe assisted synthesis of titanium nanoparticles is reported. The synthesis is performed at room temperature. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of Ti nanoparticles. Individual nanoparticles as well as a number of aggregates almost spherical in shape having a size of 40–60 nm are found.

  4. Ceramic materials based on modified pyrogenic titanium dioxide and titanium-silica

    International Nuclear Information System (INIS)

    Ceramic materials based on modified titanium dioxide and titanium-silica are obtained. Method for modification of titanium dioxide and titanium-silica by palladium additions in the process of flame, hydrolysis of titanium, tetrachloride or silicon tetrachloride mixture with titanium tetrachloride is developed. The above method makes it possible to modify already formed particles of the final products in the reactor cooling zone, which does not effect their size and where by the whole palladium is on the surface of the ceramic material. A series of textolite is prepared on the basis of the developed ceramic materials and their metallization is performed

  5. Effect of titanium content and aging temperature on the properties of uranium-titanium alloys

    International Nuclear Information System (INIS)

    The mechanical properties and microstructures of four uranium-titanium alloys were examined as functions of titanium content and aging temperature. Titanium alloy content was varied from 0.41 to 0.79 weight percent. Aging temperatures from 350 to 4500C (all for six hours) were evaluated for each alloy in addition to tests in the unaged conditions. Titanium and aging temperature were both shown to be strong effects in determining alloy properties. It was determined that the uranium-0.41 weight percent titanium alloy underwent extensive age-hardening even though the alloy did not exhibit a martensitic microstructure characteristic of the alloys richer in titanium

  6. 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. PMID:24298207

  7. 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.

  8. Effects of Low Temperature on Hydrogen-Assisted Crack Growth in Forged 304L Austenitic Stainless Steel

    Science.gov (United States)

    Jackson, Heather; San Marchi, Chris; Balch, Dorian; Somerday, Brian; Michael, Joseph

    2016-08-01

    The objective of this study was to evaluate effects of low temperature on hydrogen-assisted crack propagation in forged 304L austenitic stainless steel. Fracture initiation toughness and crack-growth resistance curves were measured using fracture mechanics specimens that were thermally precharged with 140 wppm hydrogen and tested at 293 K or 223 K (20 °C or -50 °C). Fracture initiation toughness for hydrogen-precharged forgings decreased by at least 50 to 80 pct relative to non-charged forgings. With hydrogen, low-temperature fracture initiation toughness decreased by 35 to 50 pct relative to room-temperature toughness. Crack growth without hydrogen at both temperatures was microstructure-independent and indistinguishable from blunting, while with hydrogen microcracks formed by growth and coalescence of microvoids. Initiation of microvoids in the presence of hydrogen occurred where localized deformation bands intersected grain boundaries and other deformation bands. Low temperature additionally promoted fracture initiation at annealing twin boundaries in the presence of hydrogen, which competed with deformation band intersections and grain boundaries as sites of microvoid formation and fracture initiation. A common ingredient for fracture initiation was stress concentration that arose from the intersection of deformation bands with these microstructural obstacles. The localized deformation responsible for producing stress concentrations at obstacles was intensified by low temperature and hydrogen. Crack orientation and forging strength were found to have a minor effect on fracture initiation toughness of hydrogen-supersaturated 304L forgings.

  9. 396柴油机连杆模锻成形工艺研究%Research on forming technology for 396 diesel engine connecting rod die forging

    Institute of Scientific and Technical Information of China (English)

    李志广; 安文忠; 刘振杰

    2013-01-01

    Taking 396 diesel engine connecting rod as a research object, the die forging forming process for the connecting rod formed on the die forging hammer with a relatively small blow energy of 30 kN was analyzed, meanwhile, the connecting rod die forging forming results on 30 kN and 50 kN die forging hammer were analyzed and compared separately. Through optimizing forging die design ( including optimizing the design of die forging process, pre-forging hot forging, finish-forging hot forging, punching the skins of pre-forging and finish-forging, pressure concave skins and flash gutter), the experiment results show that the quality rate of connecting rod die forging is improved from 94% to 98%, the production cycle of 300 pieces of die forging is reduced to 6 days at least, the efficiency of die forging is doubled, and the cost is reduced by 40% at least.%以396柴油机连杆为研究对象,针对该连杆在相对打击能量较小的30 kN模锻锤上的模锻成形工艺进行分析,比较了396柴油机连杆分别在30 kN模锻锤和50 kN模锻锤上的模锻成形效果,并对连杆锻模设计的相关内容:模锻工步、预锻热锻件形状、终锻热锻件形状、预锻和终锻的冲孔连皮、压凹连皮以及飞边槽等进行优化设计与实验验证.实验结果表明:连杆锻件合格品率由原94%提高到98%,减少锻造生产周期至少6天/300件,提高模锻效率至少1倍,锻造成本至少降低40%.

  10. Derivation of uranium residual radioactive material guidelines for the Aliquippa Forge site

    International Nuclear Information System (INIS)

    Residual radioactive material guidelines for uranium were derived for the Aliquippa Forge site in Aliquippa, Pennsylvania. This site has been identified for remedial action under the Formerly Utilized Sites Remedial Action Program (FUSRAP) of the US Department of Energy (DOE). The uranium guidelines were derived on the basis of the requirement that the 50-year committed effective dose equivalent to a hypothetical individual who lives or works in the immediate vicinity of the Aliquippa Forge site should not exceed a dose of 100 mrem/yr following decontamination. The DOE residual radioactive material guideline computer code, RESRAD, which implements the methodology described in the DOE manual for implementing residual radioactive material guidelines, was used in this evaluation. Four potential scenarios were considered for the site; the scenarios vary with regard to time spent at the site, sources of water used, and sources of food consumed. The results of the evaluation indicate that the basic dose limit of 100 mrem/yr will not be exceeded for uranium within 1,000 years, provided that the soil concentration of combined uranium (uranium-234, uranium-235, and uranium-238) at the Aliquippa Forge site does not exceed the following levels: 1,700 pCi/g for Scenario A (industrial worker: the expected scenario); 3,900 pCi/g for Scenario B (recreationist: a plausible scenario); 20 pCi/g for Scenario C (resident farmer using well water as the only water source: a possible but unlikely scenario), and 530 pCi/g for Scenario D (resident farmer using a distant water source not affected by site conditions as the only water source: a possible but unlikely scenario). The uranium guidelines derived in this report apply to the combined activity concentration of uranium-234, uranium-235, and uranium-238 and were calculated on the basis of a dose of 100 mrem/yr

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

    Science.gov (United States)

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

    2016-03-01

    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.

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

    International Nuclear Information System (INIS)

    Highlights: • The as-forged Fe25Co75 alloy shows the magnetostriction of 108 ppm. • The as-cold rolled Fe25Co75 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 Fe1−xCox (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 Fe25Co75 alloy was 108 ppm and that of the as-cold rolled Fe25Co75 alloy measured parallel to the rolling direction (RD) was 128 ppm. The cold-rolled Fe25Co75 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 Fe25Co75 and Fe20Co80 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

  13. Dynamic globularization prediction during cogging process of large size TC11 titanium alloy billet with lamellar structure

    Directory of Open Access Journals (Sweden)

    Hong-wu Song

    2014-03-01

    Full Text Available The flow behavior and dynamic globularization of TC11 titanium alloy during subtransus deformation are investigated through hot compression tests. A constitutive model is established based on physical-based hardening model and phenomenological softening model. And based on the recrystallization mechanisms of globularization, the Avrami type kinetics model is established for prediction of globularization fraction and globularized grain size under large strain subtransus deformation of TC11 alloy. As the preliminary application of the previous results, the cogging process of large size TC11 alloy billet is simulated. Based on subroutine development of the DEFORM software, the coupled simulation of one fire cogging process is developed. It shows that the predicted results are in good agreement with the experimental results in forging load and microstructure characteristic, which validates the reliability of the developed FEM subroutine models.

  14. 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

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

    International Nuclear Information System (INIS)

    Highlights: ► Solutionizing of 1250 °C and ageing of 500–1000 °C was done for hot forged SASS. ► Strength and toughness increased by 25% on hot forged than the cast SASS. ► Amounts of precipitates after ageing were evaluated by thermo-calc. ► Sigma forms from chi at 900 °C and contains constant Cr and Mo contents, unlike chi. ► Sigma is incoherent, contains high Mo and causes low toughness at 900 °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 °C. The forging was then solutionized at 1250 °C and aged for 1 h and 10 h at different temperatures in the range of 500–1000 °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 °C, and sigma at temperatures above 900 °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 °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 °C and can be as detrimental to toughness of SASS as chi or carbides and nitrides.

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

    DEFF Research Database (Denmark)

    Jinming, Sha

    on die surface vibration in forging process. After a general introduction to friction mechanisms and friction test techniques in metal forming, the application of ultrasonic vibration in metal forming, the influence of sliding velocity on friction is described. Some earlier investigations of the......, especially the influence on metal flow, stress and strain distribution. The results from FEM simulation show that die surface vibration have significant influence on the metal flow, strain and stress distributions in a deformed work piece. Finally, a number of validation tests with or similar to industrial...

  17. Life Enhancement of Hot-Forging Dies by Plasma-Nitriding

    OpenAIRE

    ÇAPA, Mehmet; TAMER, Muzaffer; GÜLMEZ, Turgut; BODUR, Cengiz Tahir

    2000-01-01

    Hot-forging dies, made of AISI-H13 hot-work tool steel, were plasma-nitrided in order to improve the surface properties of the material. A diffusion layer without the white layer was formed on the material by controlling the nitriding parameters: vacuum pressure, temperature, N2 / H2 ratio and DC bias potential. The nitriding time was varied from 2 to 16 hours. Micro-hardness measurements were performed on the surface and through the diffusion layer for each nitrided material. Optical microsc...

  18. Research on Simulation of Giant Forging Hydraulic Press Decoupling Control for Synchronous Control System

    Directory of Open Access Journals (Sweden)

    Xinliang Liu

    2013-06-01

    Full Text Available A giant forging hydraulic press active synchronous control system is a mutually-coupled multi-input and multi-output system. To solve the elimination of the multi-channel interference, a multiple-input and multiple-output mathematical model center on active-beam is established; multi-channel synchronous decoupling control strategy is studied. The simulation results show that: the system eliminates the role of strong interference between multi-channel accesses to very good inhibitory effect of synchronization error, eliminating the system's external disturbance on the synchronization precision control impact.

  19. Simulated comparison on kinematics properties of two typical mechanisms of forging manipulator

    Science.gov (United States)

    Ren, Yunpeng; Lu, Chongshao; Han, Qingkai; Zhang, Tianxia; Wen, Bangchun

    2007-12-01

    The kinematics of two typical mechanisms is analyzed following the concept design of a 4MNm forging manipulator for a huge hydraulic press, i.e. a parallel links mechanism and a swing links mechanism. For the first kind of mechanism, when the jaw swings up and down, the swing angle is in proportion to the extending length of its driving hydraulic cylinder. For the second kind of mechanism, it is mostly difficult for the fluid driving control system to make sure three hydraulic pressure cylinders to keep moving synchronously. Based on these simulations and considering practical technological demands, the first kind of mechanism with parallel links is chosen as a better one.

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

    OpenAIRE

    Jianbo TAN; YANG Shuai; Li, Yichao

    2016-01-01

    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 all...

  1. 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...... experimental work carried out in order to establish the models. The constitutive equations represent the materials properties mathematically and define the relationships between load, deformation, lifetime cycles, crack growth rates and stress intensities....

  2. 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....

  3. Tribological Investigations of Hard-Faced Layers and Base Materials of Forging Dies with Different Kinds of Lubricants Applied

    Directory of Open Access Journals (Sweden)

    V. Lazić

    2010-12-01

    Full Text Available This paper gives a procedure for choosing the right technology for reparative hard facing of damaged forging dies. Since they are subject to impact loads and cyclic temperature elevations, forging dies should be made of steel that is able to withstand great impact loads, maintain good mechanical properties at elevated temperatures and that is resistant to wear and thermal fatigue. For these reasons, forging dies are made of conditionally weldable alloy tool steels; however it makes hard facing of damaged tools even more difficult. In this paper, wear resistance of base materials, hard-faced layers and heat-affected zones are tribologically investigated when two different lubricants - pure synthetical oil LM 76 and LM 76 with 6% molybdenum disulfide (MoS2 are applied. Tribological investigations have shown that the wear resistance of the hard faced layers is considerably greater than the wear resistance of the base material. However, the base material has better properties concerning friction.

  4. Microstructural control in forged hardened-tempered 1050 steel for front-wheel hub for motor cars

    International Nuclear Information System (INIS)

    The application forged-normalized-hardened-tempered 1050 steel in the front-wheel-hub (FWH ) of modern motor-cars necessitates a controlled microstructure i.e a good tempered martensite. Research in areas of heat treatment and metallography is conducted on forged 1050 steel, for FWH of modern motor cars. Experiments are conducted by use of modern (high precision) microhardness machine and metallographic equipment. The microstructure is quantitatively analyzed; and the ASTM Grain Size No. is calculated to be 8. The microstructural analysis and the structure/property relationship reveal that the material: forged normalized hardened tempered 1050 steel, when heat treated under controlled conditions, is appropriate for application in FWH of modern motor cars. (author)

  5. Fabrication of large rotor forged piece of the 35KhN3MFA steel with low transition temperature

    International Nuclear Information System (INIS)

    Tested is the melting procedure of rotor 35KhN3MFA steel and casting of the 87 t mass ingot for the billet of final part of the turbine rotor bolted together. The melting has been made using the plant of out-of-furnace refining and degassing, cabon deoxidation at degassing has been carried out during the casting. Obtained ingots have been subjected to forging and heat treatment. Mechanical properties and transition temperature of brittleness of produced forged pieces have been studied. It is found out that in the axial zone of the billet the yield strength of 740MPa and transition temperature of -13...+10 deg C are reached. The yield strength at the radius middle constitutes 690MPa, transition temperature - +22 deg C that considerably surpasses properties of billets obtained by traditional methods. The forged piece, produced, provides rotor reliability in operation

  6. Recycling potential of titanium alloys

    International Nuclear Information System (INIS)

    This study examines just how long one must contain radioactive titanium before it can be safely reprocessed. It was assumed that the spent first wall and blanket structural material would be completely reprocessed in a standard manufacturing facility capable of both primary and secondary fabrication. It was found that reprocessing could occur when the chemical hazard associated with inhalation was greater than the hazard associated with inhalating the same amount of radioactive species. This conclusion allowed the use of the threshold limiting value (TLV) to set a limit on the airborne concentration of the elements. Then by calculating the time required for that amount of material to decay to the same diluent factor indicated by the biological hazard potential (BHP) in air, the time for reprocessing was determined. Based on these assumptions, it was determined that it is feasible to think of titanium, and some of its alloying elements as being recyclable in a relatively short time period

  7. Carbon nanotube-based coatings on titanium

    Indian Academy of Sciences (India)

    Elzbieta Dlugon; Wojciech Simka; Aneta Fraczek-Szczypta; Wiktor Niemiec; Jaroslaw Markowski; Marzena Szymanska; Marta Blazewicz

    2015-09-01

    This paper reports results of the modification of titanium surface with multiwalled carbon nanotubes (CNTs). The Ti samples were covered with CNTs via electrophoretic deposition (EPD) process. Prior to EPD process, CNTs were functionalized by chemical treatment. Mechanical, electrochemical and biological properties of CNT-covered Ti samples were studied and compared to those obtained for unmodified titanium surface. Atomic force microscopy was used to investigate the surface topography. To determine micromechanical characteristics of CNT-covered metallic samples indentation tests were conducted. Throughout electrochemical studies were performed in order to characterize the impact of the coating on the corrosion of titanium substrate. In vitro experiments were conducted using the human osteoblast NHOst cell line. CNT layers shielded titanium from corrosion gave the surface-enhanced biointegrative properties. Cells proliferated better on the modified surface in comparison to unmodified titanium. The deposited layer enhanced cell adhesion and spreading as compared to titanium sample.

  8. ROUGH SURFACES OF TITANIUM AND TITANIUM ALLOYS FOR IMPLANTS AND PROSTHESES

    OpenAIRE

    Conforto, Egle; Aronsson, Bjorn-Owe; Salito, A.; Crestou, Catherine; Caillard, Daniel

    2004-01-01

    Titanium and titanium alloys for dental implants and hip prostheses were surface-treated and/or covered by metallic or ceramic rough layers after being submitted to sand blasting. The goal of these treatments is to improve the surface roughness and, consequently, the osteointegration, the fixation and the stability of the implant. The microstructure of titanium and titanium alloys submitted to these treatments has been studied and correlated to their mechanical behavior. As treated/ covered a...

  9. Titanium Dioxide as Photocatalytic Agent

    Czech Academy of Sciences Publication Activity Database

    Spáčilová, Lucie; Maléterová, Ywetta; Křesinová, Zdena; Cajthaml, Tomáš; Šolcová, Olga

    Prague : Orgit, 2014, s. 39. ISBN 978-80-02-02555-9. [International Congress of Chemical and Process Engineering /21./ - CHISA 2014 and Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction /17./ - PRES 2014. Prague (CZ), 23.08.2014-27.08.2014] Grant ostatní: NATO(US) SPS984398 Institutional support: RVO:67985858 ; RVO:61388971 Keywords : endocrine disruptors * titanium dioxide * experiments Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  10. PLASMA ELECTROLYTIC OXIDATION OF TITANIUM

    OpenAIRE

    Aliasghari, Sepideh *

    2014-01-01

    Plasma electrolytic oxidation is used to prepare corrosion- and wear-resistant coatings on light metals. The extensive literature reports on coatings formed under a wide range of different electrical regimes and in diverse electrolyte compositions. However, little work is available that investigates systematically PEO of titanium under a range of electrical variables in a particular electrolyte. In the present work, coatings are formed in a silicate electrolyte under a range of current densit...

  11. Titanium metal obtention by fused salts electrolysis

    International Nuclear Information System (INIS)

    Potassium fluorotitanate dissolved in fused sodium chloride or potassium chloride may be electrolyzed under an inert gas atmosphere. Solid electrolysis products are formed on the cathode which contains titanium metal, sodium chloride, lower fluorotitanates and small quantities of alkali metal fluorotitanate. The extraction of titanium from the electrolysis products may be carried out by aqueous leaching (removal of chloride salts of alkali metals and a certain amount of fluorotitanates). Titanium metal obtained is relatively pure. (Author)

  12. INVESTIGATION OF COMBUSTION IN TITANIUM-FERROSILICON SYSTEM

    OpenAIRE

    Shatokhin, Igor; Bigeev, Vahit; Shaymardanov, Kamil; Manashev, Ildar

    2013-01-01

    Results of self-sustaining combustion process in the titanium-ferrosilicon system investigations are presented. These data were used for experimental-industrial technology developing of production ferro silico titanium with high titanium content for steel alloying.

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

    Directory of Open Access Journals (Sweden)

    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.

  14. Coupled Thermo-Mechanical Modeling of Long Cone-Shaped Forging Based on Rigid Visco-Plastic FEM

    Institute of Scientific and Technical Information of China (English)

    刘雪峰; 汪凌云; 张利

    2002-01-01

    Based on synthetically considering the coupled thermo-mechanical relations between temperature and deforming, a numerical simulation of the forging process for the special long cone-shaped workpiece of Al-5.44Mg-2.15Li-0.12Zr alloy at high temperature was conducted by using the rigid visco-plastic finite element method. The relations between the total load and the displacement during the forging, and the distributions of stress, strain, temperature and strain rate, which can provide useful information for the process design, are obtained.

  15. Evaluation of HIP-plus-forged Ti--6Al--2Sn--4Zr--6Mo discs made from REP power preforms

    International Nuclear Information System (INIS)

    An investigation was undertaken to evaluate the forgeability, the structural characteristics, and the mechanical properties of Ti--6Al--2Sn--4Zr--6Mo disk forgings processed from rotating electrode process-hot isostatic pressing (REP-HIP) powder preforms. It was shown that the powder preforms exhibited excellent forgeability in both (α+β) and β ranges. Among various processing conditions examined, the as (α+β) forged powder preforms gave the best room temperature and high temperature tensile properties. However, the optimum combination of tensile properties, creep strength and stability, and fracture toughness was obtained for as β-forged disks. The results also demonstrated that the powder forgings are very sensitive to heat treatment, and the tensile ductility varies significantly with specimen orientation. Additional observations are made on the die-chilled surface layers in the β-processed forgings

  16. The effects of hydrogen embrittlement of titanium

    Science.gov (United States)

    Taylor, Delbert J.

    1989-01-01

    Titanium alloys, by virtue of their attractive strength to density ratio, fatigue, fracture toughness and corrosion resistance are now commonly used in various aerospace and marine applications. The cost, once very expensive, has been reduced, making titanium even more of a competitive material today. Titanium and titanium alloys have a great affinity to several elements. Hydrogen, even in small amounts, can cause embrittlement, which in turn causes a reduction in strength and ductility. The reduction of strength and ductility is the subject of this investigation.

  17. Titanium alloys Russian aircraft and aerospace applications

    CERN Document Server

    Moiseyev, Valentin N

    2005-01-01

    This text offers previously elusive information on state-of-the-art Russian metallurgic technology of titanium alloys. It details their physical, mechanical, and technological properties, as well as treatments and applications in various branches of modern industry, particularly aircraft and aerospace construction. Titanium Alloys: Russian Aircraft and Aerospace Applications addresses all facets of titanium alloys in aerospace and aviation technology, including specific applications, fundamentals, composition, and properties of commercial alloys. It is useful for all students and researchers interested in the investigation and applications of titanium.

  18. Titanium Matrix Composite Pressure Vessel Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For over 15 years, FMW Composite Systems has developed Metal Matrix Composite manufacturing methodologies for fabricating silicon-carbide-fiber-reinforced titanium...

  19. Plasmonic titanium nitride nanostructures for perfect absorbers

    DEFF Research Database (Denmark)

    Guler, Urcan; Li, Wen-Wei; Kinsey, Nathaniel; Naik, Gururaj V.; Boltasseva, Alexandra; Guan, Jianguo; Kildishev, Alexander V.; Shalaev, Vladimir M.

    2013-01-01

    We propose a metamaterial based perfect absorber in the visible region, and investigate the performance of titanium nitride as an alternative plasmonic material. Numerical and experimental results reveal that titanium nitride performs better than gold as a plasmonic absorbing material.Renewable E......We propose a metamaterial based perfect absorber in the visible region, and investigate the performance of titanium nitride as an alternative plasmonic material. Numerical and experimental results reveal that titanium nitride performs better than gold as a plasmonic absorbing material...

  20. Appcelerator Titanium patterns and best practices

    CERN Document Server

    Pollentine, Boydlee

    2013-01-01

    The book takes a step-by-step approach to help you understand CommonJS and Titanium architecture patterns, with easy to follow samples and plenty of in-depth explanations If you're an existing Titanium developer or perhaps a new developer looking to start off your Titanium applications "the right way", then this book is for you. With easy to follow examples and a full step-by-step account of architecting a sample application using CommonJS and MVC, along with chapters on new features such as ACS, you'll be implementing enterprise grade Titanium solutions in no time. You should have some JavaSc

  1. 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.

  2. 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.

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

    International Nuclear Information System (INIS)

    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

  4. Standard method of macroetch testing steel bars, billets, blooms, and forgings

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 Macroetching, which is the etching of specimens for macrostructural examination at low magnifications, is a frequently used technique for evaluating steel products such as bars, billets, blooms, and forgings. 1.2 Included in this method is a procedure for rating steel specimens by a graded series of photographs showing the incidence of certain conditions. The method is limited in application to bars, billets, blooms, and forgings of carbon and low alloy steels. 1.3 A number of different etching reagents may be used depending upon the type of examination to be made. Steels react differently to etching reagents because of variations in chemical composition, method of manufacture, heat treatment and many other variables. Establishment of general standards for acceptance or rejection for all conditions is impractical as some conditions must be considered relative to the part in which it occurs. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is ...

  5. Camera calibration method for dimensional measurement of heavy forging in large scale

    Science.gov (United States)

    Liu, Bin; Hu, Chunhai; Song, Xiaoxue; Zhao, Zhenqing

    2009-07-01

    Camera calibration method plays an important role in the stereovision system to resolve the problems of dimensional measurement of heavy forging. Due to the intensive vibrating, the camera parameters must be calibrated every time after the action of the water press. This paper presents a method using the scene geometry to calibrate cameras. In the context of heavy machinery environments, the constraints which can be used are parallelism and orthogonality. These constraints lead to geometrically intuitive methods to calibrate the cameras. The huge forging equipment such as water press belongs to geometrically constrained object and insusceptible to vibrating, which gives natural prior knowledge and constraint conditions for 3-D reconstruction. The method focuses on the calibration of the extrinsic parameters which are subject to change since the effects of the workspace factors. The intrinsic parameters were calibrated in advance by an off-line method and were assumed as invariable. The results of simulation experiments demonstrate that the camera parameters could be calibrated effectively and achieve the real time need.

  6. Automatic manipulator for severe forging works; 3K sagyo no jidoka ni katsuyakusuru tanzoyo manipurator

    Energy Technology Data Exchange (ETDEWEB)

    Izawa, T.; Obitsu, K.; Arakawa, T.; Maezato, N. [Meidensha Corp., Tokyo (Japan)

    1997-06-30

    The manipulator with automatic operation function and teaching function was developed for work handling between forging lines. This manipulator is composed of a main body, hand, joy-stick operation equipment and manipulator controller. The arm has horizontal articulated structures such as the 1st axis for vertical motion, 2nd and 3rd axes for horizontal swing and 4th axis for horizontal swing of an end effector as hand. The hand is safeguarded with several measures against heat, dust, water, vibration and impact to directly grasp forging works around 1250degC. The joy- stick operation equipment indicates motions in joint angle, orthogonal and tool coordinate systems. The dust-proof manipulator controller is equipped with a heat exchanger and cooler for cooling of the inside of the controller. The manipulator is controlled by 4 CPUs such as man-machine CPU, servo computing CPU, computing CPU for interpolation and CPU for a display panel to achieve high speed processing and module structure. 7 figs., 4 tabs.

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

    International Nuclear Information System (INIS)

    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) Al2CuMg (S) which nucleated heterogeneously on grain boundaries and (ii) Mg(Zn,Cu,Al)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 (R2) 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

  8. AP1000 steam generator tube sheet forging cladding quality issue analysis and precaution method

    International Nuclear Information System (INIS)

    The dimension of AP1000 Steam Generator is 4500 mm × H1170 mm. Many cracks which length between 9∼ 50 mm, depth between 10∼14 mm are found through Ultrasonic Inspection after cladding. The material of AP1000 Steam Generator is ASME SA508 Grade 3 Class 2. The metallurgical structure of ASME SA508 Grade 3 Class 2 is sorbite (cubic body-centered). The low hydrogen dissolvability in cubic body-centered structure is easy resulting cracks. The cladding material is 690 nickel-base alloy which structure is face-centered cubic. Hydrogen has a bigger dissolvability in face-centered cubic structure. So if the hydrogen is not removed enough during welding, many cracks would generate. The reason why cracks generated after cladding is the preheat method and post heat temperature, post heat occasion and the high hydrogen content of forging itself. In order to obtain the qualified product after cladding, the welding process shall be decided through the theory and process analysis based on the consideration for the high hydrogen content and residual stress of the forging. The situation of cracks generated after cladding is described. The methods for precaution such cracks are provided. (author)

  9. Theoretical and Experimental Research on Forge Rolling Process of Preforms From Magnesium Alloy AZ31

    Directory of Open Access Journals (Sweden)

    Bulzak T.

    2015-04-01

    Full Text Available This paper presents results of theoretical and experimental research works on the rolling process of a lever preform from magnesium alloy AZ31. The forge rolling process of the preform was realized in the system oval-circle. The paper focuses mainly on kinematics of material flow and proper filling of rolling impressions. Research aiming at determining possibilities of faults presence in the form of cracks, overlapping and improper filling of the impressions were also conducted. During experimental research it was noticed that material cracking took place at the moment of material clamping by rolls. Moreover, it was stated that this cracking may be the result of large shearing stresses action, appearing at the moment of material clamping by rolls. Shearing stresses values were determined on the basis of numerical calculations. Next, tools were modified in order to lower tangential stresses at the moment of material clamping by rolls. The further experimental research with modified tools confirmed the rightness of the assumptions. On the basis of conducted works on the forge rolling process of magnesium alloy AZ31, it was stated that when material is clamped by tools tangential stresses intensification should not take place.

  10. A Method For Producing Hollow Shafts By Rotary Compression Using A Specially Designed Forging Machine

    Directory of Open Access Journals (Sweden)

    Tomczak J.

    2015-09-01

    Full Text Available The paper presents a new method for manufacturing hollow shafts, where tubes are used as billet. First, the design of a specially designed forging machine for rotary compression is described. The machine is then numerically tested with regard to its strength, and the effect of elastic strains of the roll system on the quality of produced parts is determined. The machine’s strength is calculated by the finite element method using the NX Nastran program. Technological capabilities of the machine are determined, too. Next, the results of the modeling of the rotary compression process for a hollow stepped shafts by the finite element method are given. The process for manufacturing hollow shafts was modeled using the Simufact.Forming simulation program. The FEM results are then verified experimentally in the designed forging machine for rotary compression. The experimental results confirm that axisymmetric hollow shafts can be produced by the rotary compression method. It is also confirmed that numerical methods are suitable for investigating both machine design and metal forming processes.

  11. Forging Ahead

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Recent moves have put the North Korean nuclear issue on the fast track to final settlement After a five-month stalemate, the United StatesandNorthKorea final-ly surmounted the first obstacle in the “action for action” phase in resolving the latter’s nucl

  12. The vapour phase deposition of boron on titanium by the reaction between gaseous boron trichloride and titanium metal. Final report

    International Nuclear Information System (INIS)

    The reaction, between boron trichloride vapour and titanium has been investigated in the temperature range 200 - 1350 deg. C. It has been found that an initial reaction leads to the formation of titanium tetrachloride and the deposition of boron on titanium, but that except for reactions between 900 and 1000 deg. C, the system is complicated by the formation of lower titanium chlorides due to secondary reactions between the titanium and titanium tetrachloride

  13. Seam-welded titanium tube as well as titanium tubesheet for all-titanium condenser of power plants

    International Nuclear Information System (INIS)

    Most of the thermal and nuclear power plants in Japan are located on the coast line, and steam turbine condenser and heat exchanger use a great quantity of sea water for cooling. This paper describes about thin wall welded tube for all-titanium condenser, development of technology for manufacturing titanium tubesheet, and the present situation of application

  14. 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...

  15. Influence of Single and Double Stage Forging on Cutting Forces of Al 7075/BSF Metal Matrix Composites

    OpenAIRE

    Karthigeyan, R.; Ranganath, G.

    2014-01-01

    In the present study, an attempt has been made to investigate the influence of the forging parameters on cutting forces for different cutting speed, depth of cut, and feed rate during machining of Al 7075 alloy and Al 7075 alloy with short basalt fiber reinforced metal matrix composites. The experiments were conducted by using a lathe machine with tool dynamometer setup.

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

    International Nuclear Information System (INIS)

    For the reactor pressure vessel (RPV) of the high temperature engineering test reactor (HTTR) which has been developed by the Japan Atomic Energy Research Institute (JAERI), 2.25Cr-1Mo steel is used for the first time in the world for a nuclear reactor pressure vessel. The RPV is 13.2 m in height and 5.5 m in internal diameter. Operation temperature is about 400 C and the internal pressure is 4 MPa. A material confirmation test has been carried out to demonstrate good applicability of forged low Si 2.25Cr-1Mo steel to the RPV of the HTTR. Recently, Japan Steel Works has succeeded in manufacturing large size ring forgings and a large size forged cover dome integrated with nozzles for the 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 the stand pipe. (orig.)

  17. The Invalidation Analysis of a Working 5 CrMnMo Forging Die and Ways of Precaution

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The paper introduced the 5 CrMnMo steel, including the chemical composition, the heat treatment technology, the forging die working condition, and the invalidation form (such as the cavity arris wear, the cavity subsidence, the cold and the heat fatigue crackle). Then gave some precautions for prolonging the mould life by improving the heat treatment technology.

  18. Influence of Single and Double Stage Forging on Cutting Forces of Al 7075/BSF Metal Matrix Composites

    Directory of Open Access Journals (Sweden)

    R.Karthigeyan

    2014-05-01

    Full Text Available In the present study, an attempt has been made to investigate the influence of the forging parameters on cutting forces for different cutting speed, depth of cut, and feed rate during machining of Al 7075 alloy and Al 7075 alloy with short basalt fiber reinforced metal matrix composites. The experiments were conducted by using a lathe machine with tool dynamometer setup.

  19. Metallurgical process for the production of heavy fine-grained forgings with optimal toughness and good welding ability

    International Nuclear Information System (INIS)

    The new by developed equipment for inserting aluminium and silicon during casting in vacuum - after vacuum carbon desoxydation (VCD) - works to satisfaction. A great developement of the technical properties were achieved by this technique. It is applied when producing forgings for reactor parts. The ingot weights are 90-250 tons. (orig.)

  20. Forging the Future between Two Different Worlds: Recent Chinese Immigrant Adolescents Tell Their Cross-Cultural Experiences

    Science.gov (United States)

    Li, Jun

    2009-01-01

    In order to understand the interplay of culture and mind in immigrant adolescent learning and psychological adjustment, this multiple-case qualitative study examined salient home and school experiences told by recent Chinese immigrant youth in semistructured interviews and narrative essays. Forging the future between two different worlds defined,…

  1. Minimal stress shielding with a Mallory-Head titanium femoral stem with proximal porous coating in total hip arthroplasty

    Directory of Open Access Journals (Sweden)

    Lombardi Adolph V

    2009-12-01

    Full Text Available Abstract Background As longevity of cementless femoral components enters the third decade, concerns arise with long-term effects of fixation mode on femoral bone morphology. We examined the long-term consequences on femoral remodeling following total hip arthroplasty with a porous plasma-sprayed tapered titanium stem. Methods Clinical data and radiographs were reviewed from a single center for 97 randomly selected cases implanted with the Mallory-Head Porous femoral component during primary total hip arthroplasty. Measurements were taken from preoperative and long-term follow-up radiographs averaging 14 years postoperative. Average changes in the proximal, middle and diaphyseal zones were determined. Results On anteroposterior radiographs, the proximal cortical thickness was unchanged medially and the lateral zone increased 1.3%. Middle cortical thickness increased 4.3% medially and 1.2% laterally. Distal cortical thickness increased 9.6% medially and 1.9% laterally. Using the anteroposterior radiographs, canal fill at 100 mm did not correlate with bony changes at any level (Spearman's rank correlation coefficient of -0.18, 0.05, and 0.00; p value = 0.09, 0.67, 0.97. On lateral radiographs, the proximal cortical thickness increased 1.5% medially and 0.98% laterally. Middle cortical thickness increased 2.4% medially and 1.3% laterally. Distal cortical thickness increased 3.5% medially and 2.1% laterally. From lateral radiographs, canal fill at 100 mm correlated with bony hypertrophy at the proximal, mid-level, and distal femur (Spearman's rank correlation coefficient of 0.85, 0.33, and 0.28, respectively; p value = 0.001, 0.016, and 0.01, respectively. Conclusion Stress shielding is minimized with the Mallory-Head titanium tapered femoral stem with circumferential proximal plasma-sprayed coating in well-fixed and well-functioning total hip arthroplasty. Additionally, the majority of femora demonstrated increased cortical thickness in all zones

  2. Titanium plasma produced by a nitrogen laser

    International Nuclear Information System (INIS)

    Titanium plasmas produced in vacuum and in air by radiation from a nitrogen laser focused onto a solid titanium target are studied spectroscopically. The energy deposition is more effective than in other cases since the wavelength of the laser is in the vicinity of Ti resonance lines. (orig.)

  3. Casting of Titanium and its Alloys

    OpenAIRE

    R. L. Saha; K. T. Jacob

    1986-01-01

    Titaniuni and its alloys have many applications in aerospace, marine and other engineering industries. Titanium requires special melting techniques because of its high reactivity at elevated temperatures and needs special mould materials and methods for castings. This paper reviews the development of titanium casting technology.

  4. Casting of Titanium and its Alloys

    Directory of Open Access Journals (Sweden)

    R. L. Saha

    1986-04-01

    Full Text Available Titaniuni and its alloys have many applications in aerospace, marine and other engineering industries. Titanium requires special melting techniques because of its high reactivity at elevated temperatures and needs special mould materials and methods for castings. This paper reviews the development of titanium casting technology.

  5. Amorphouslike diffraction pattern in solid metallic titanium

    DEFF Research Database (Denmark)

    Wang, Y.; Fang, Y.Z.; Kikegawa, T.; Lathe, C.; Saksl, K.; Franz, H.; Schneider, J.R.; Gerward, Leif; Wu, F.M.; Liu, J.F.; Jiang, J.Z.

    2005-01-01

    Amorphouslike diffraction patterns of solid elemental titanium have been detected under high pressure and high temperature using in situ energy-dispersive x-ray diffraction and a multianvil press. The onset pressure and the temperature of formation of amorphous titanium is found to be close to the...

  6. Appcelerator Titanium business application development cookbook

    CERN Document Server

    Bahrenberg, Benjamin

    2013-01-01

    Presented in easy to follow, step by step recipes, this guide is designed to lead you through the most important aspects of application design.Titanium developers who already have a basic knowledge of working with Appcelerator Titanium but want to further develop their knowledge for use with business applications

  7. Theoretical study of titanium phases

    International Nuclear Information System (INIS)

    The aim of this work is to obtain a good understanding of the phase diagram of titanium within density functional theory. This diagram is composed of the alpha phase, the high pressure omega phase and the high temperature beta phase. This requires the differences in total energy to be predicted with a great precision, because these differences are around 50 meV. I find the omega phase to be the most stable one by ab initio calculation at zero temperature and pressure, in contradiction to the experimental results. I find this inversion of the stability also appears in titanium dioxide and zirconium. I have analyzed all the approximations brought into play in the ab initio approach. I have estimated the zero point energy and studied the impact of including the semi-core states as well as the effect of the exchange-correlation functionals. The conclusion is that the usual approximations for the exchange-correlation generate the biggest part of the error. A possible correction is to take into account the electronic self-interaction. I have apply this correction to the semi-core states and find a systematic improvement of the cell parameters, but no improvement on the phase stability. So I can conclude that a better description of the exchange interaction on the localized 3d states is needed. Although the standard functionals of exchange-correlation are not accurate enough to predict the phase diagrams of titanium, they perform well in describing physical properties less demanding in terms of precision, like elastic constants. However, I find important that the predicted equilibrium volume must be precise, as these properties are found strongly dependent on the volume. (author)

  8. Electrolytic hydrogen in beta titanium

    International Nuclear Information System (INIS)

    Permeation of electrolytic hydrogen through beta titanium foils with palladium coated surfaces was studied using Ti--11.5 Mo--6 Zr--4.5 Sn. Ion bombardment etching followed by thin film vapor deposition of palladium were used to produce oxide-free titanium specimens for electrochemical hydrogen permeation and embrittlement studies. A thin metallic foil is cathodically charged with hydrogen on one side while the other side is maintained at a sufficiently anodic potential so that all the diffusing hydrogen is oxidized and turned into an equivalent current. The current is analyzed to determine diffusivity and solubility of hydrogen. X-ray diffraction was also used to determine the effects of hydrogen on the lattice parameter. Permeation experiments conducted with basic cyanide solutions exhibited simple diffusion behavior. The diffusivity at 210C for hydrogen through the beta alloy was 5.60 (+-1.92) x 10-7 cm2/s. Anomalous permeation occurred with hydrogen chemical potentials in acidic and basic solutions without cyanide during the later stages of the approach to steady state in the charging. This behavior is consistent with the trapping model of hydrogen in metals of McNabb and Foster. Plastic deformation and spontaneous cracking at the wetted portion of the specimen were observed under extreme conditions during this anomalous behavior. Part of the deformation is found to be reversible. In the mandrel bend experiments on the embrittlement phenomenon, the transgranular cleavage mode of fracture occurred. Interstitially dissolved hydrogen expanded the bcc lattice of the beta titanium with accompanying diffraction line broadening. The lattice contracted upon removal of the hydrogen. The satisfactory performance of the beta alloy Ti--11.5 Mo--6 Zr--4.5 Sn, in moderate electrochemical environments results principally from the protective oxide film

  9. Welding and Joining of Titanium Aluminides

    Directory of Open Access Journals (Sweden)

    Jian Cao

    2014-06-01

    Full Text Available Welding and joining of titanium aluminides is the key to making them more attractive in industrial fields. The purpose of this review is to provide a comprehensive overview of recent progress in welding and joining of titanium aluminides, as well as to introduce current research and application. The possible methods available for titanium aluminides involve brazing, diffusion bonding, fusion welding, friction welding and reactive joining. Of the numerous methods, solid-state diffusion bonding and vacuum brazing have been most heavily investigated for producing reliable joints. The current state of understanding and development of every welding and joining method for titanium aluminides is addressed respectively. The focus is on the fundamental understanding of microstructure characteristics and processing–microstructure–property relationships in the welding and joining of titanium aluminides to themselves and to other materials.

  10. The present status of dental titanium casting

    Science.gov (United States)

    Okabe, Toru; Ohkubo, Chikahiro; Watanabe, Ikuya; Okuno, Osamu; Takada, Yukyo

    1998-09-01

    Experimentation in all aspects of titanium casting at universities and industries throughout the world for the last 20 years has made titanium and titanium-alloy casting nearly feasible for fabricating sound cast dental prostheses, including crowns, inlays, and partial and complete dentures. Titanium casting in dentistry has now almost reached the stage where it can seriously be considered as a new method to compete with dental casting using conventional noble and base-metal alloys. More than anything else, the strength of titanium’s appeal lies in its excellent biocompatibility, coupled with its comparatively low price and abundant supply. Research efforts to overcome some problems associated with this method, including studies on the development of new titanium alloys suitable for dental use, will continue at many research sites internationally.

  11. Texture evolution in upset-forged P/M and wrought tantalum: Experimentation and modeling

    International Nuclear Information System (INIS)

    Preferred orientations in polycrystalline materials can significantly affect their physical and mechanical response through the retention of anisotropic properties inherent to the single crystal. In this study the texture evolution in upset-forged PIM and wrought tantalum was measured as a function of initial texture, compressive strain, and relative position in the pressing. A / duplex fiber texture parallel to the compression axis was generally observed, with varying degrees of a radial component evident in the wrought material. The development of deformation textures derives from restricted crystallographic slip conditions that generate lattice rotations, and these grain reorientations can be modeled as a function of the prescribed deformation gradient. Texture development was simulated for equivalent deformations using both a modified Taylor approach and a viscoplastic self-consistent (VPSC) model. A comparison between the predicted evolution and experimental results shows a good correlation with the texture components, but an overly sharp prediction at large strains from both the Taylor and VPSC models

  12. Effects of Forged Stock and Pure Aluminum Coating on Cryogenic Performance of Heat Treated Aluminum Mirrors

    Science.gov (United States)

    Toland, Ronald W.; Ohl, Raymond G.; Barthelmy, Michael P.; Zewari, S. Wahid; Greenhouse, Matthew A.; MacKenty, John W.

    2003-01-01

    We present the results of an on-going test program designed to empirically determine the effects of different stress relief procedures for aluminum mirrors. Earlier test results identified a preferred heat treatment for flat and spherical mirrors diamond turned from blanks cut out of Al 6061-T651 plate stock. Further tests have been performed on mirrors from forged stock and one set from plate stock coated with Alumiplate(trademark) aluminum coating to measure the effect of these variables on cryogenic performance. The mirrors are tested for figure error and radius of curvature at room temperature and at 80 K for three thermal cycles. We correlate the results of our optical testing with heat treatment and metallographic data.

  13. Development of Replacements for Phoscoating Used in Forging, Extrusion and Metal Forming Processes

    Energy Technology Data Exchange (ETDEWEB)

    Kerry Barnett

    2003-03-01

    Many forging, extrusion, heading and other metal forming processes use graphite-based lubricants, phosphate coatings, and other potentially hazardous or harmful substances to improve the tribology of the metal forming process. The application of phosphate-based coatings has long been studied to determine if other synthetic ''clean'' lubricants could provide the same degree of protection afforded by phoscoatings and its formulations. So far, none meets the cost and performance objectives provided by phoscoatings as a general aid to the metal forming industry. In as much as phoscoatings and graphite have replaced lead-based lubricants, the metal forming industry has had previous experience with a legislated requirement to change processes. However, without a proactive approach to phoscoating replacement, many metal forming processes could find themselves without a cost effective tribology material necessary for the metal forming process

  14. Grain size and texture changes of magnesium alloy AZ31 during multi-directional forging

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Grain size and texture changes of magnesium alloy AZ31 were studied in multidirectional forging(MDF) under decreasing temperature conditions. MDF was carried out up to large cumulative strains of 4.8 with changing the loading direction during decrease in temperature from pass to pass. MDF can accelerate the uniform development of fine-grained structures and increase the plastic workability at low temperatures. As a result, the MDFed alloy shows excellent higher strength as well as moderate ductility at room temperature even at the grain size below 1 μm. Superplastic flow takes place at 423 K and depends on the anisotropy of MDFed samples. The mechanisms of strain-induced free-grained structure development and of the plastic deformation were discussed in detail.

  15. Fatigue life analysis of die forged railway axle manufactured from C30 steel

    Directory of Open Access Journals (Sweden)

    Libor Trško

    2014-06-01

    Full Text Available With respect to the manufacturing process, different parts of one structural component can have different fatigue properties. In this study, the fatigue life of a railway axle manufactured from C30 steel by die forging is evaluated in the part of the axle bolster and axle body. According to the fatigue test results obtained at high frequency tension - compression fatigue tests (f ≈ 20 kHz, R = -1, T = 20 ± 5 °C, due to the higher level of work hardening of the axle bolster, the fatigue strength of material in this part is significantly higher than in the axle body. Different fatigue strength of these parts were observed despite the fact, that results of static tensile tests did not proved any important differences in the ultimate tensile strength, yield point and elongation. 

  16. Micromechanisms of fatigue crack growth in a forged Inconel 718 nickel-based superalloy

    International Nuclear Information System (INIS)

    The micromechanisms of fatigue crack propagation in a forged, polycrystalline IN 718 nickel-based superalloy are evaluated. Fracture modes under cyclic loading were established by scanning electron microscopy analysis. The results of the fractographic analysis are presented on a fracture mechanism map that shows the dependence of fracture modes on the maximum stress intensity factor, Kmax, and the stress intensity factor range, ΔK. Plastic deformation associated with fatigue crack growth was studied using transmission electron microscopy. The effects of ΔK and Kmax on the mechanisms of fatigue crack growth in this alloy are discussed within the context of a two-parameter crack growth law. Possible extensions to the Paris law are also proposed for crack growth in the near-threshold and high ΔK regimes. (orig.)

  17. High temperature strain hardening behavior in double forged and potassium doped tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Hua, E-mail: shenghualjh@gmail.com [Structural Material Group, Institute of Nuclear Materials Science, SCK-CEN, Mol (Belgium); Department of Applied Physics, Ghent University, St. Pietersnieuwstraat 41, 9000 Ghent (Belgium); Van Oost, Guido [Department of Applied Physics, Ghent University, St. Pietersnieuwstraat 41, 9000 Ghent (Belgium); Zhurkin, Evgeny [Structural Material Group, Institute of Nuclear Materials Science, SCK-CEN, Mol (Belgium); Experimental Nuclear Physics Department, K-89, Faculty of Physics and Mechanics, Saint-Petersburg State Polytechnical University, 29 Polytekhnicheskaya Str., 195251 St. Petersburg (Russian Federation); Terentyev, Dmitry [Structural Material Group, Institute of Nuclear Materials Science, SCK-CEN, Mol (Belgium); Dubinko, Vladimir I. [NSC Kharkov Institute of Physics and Technology, Kharkov 61108 (Ukraine); Uytdenhouwen, Inge [Structural Material Group, Institute of Nuclear Materials Science, SCK-CEN, Mol (Belgium); Vleugels, Jozef [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, 3001 Leuven (Belgium)

    2014-01-15

    The strain-hardening behavior of two recently developed double forged and K-doped tungsten grades in the 300–2000 °C range was analyzed applying a phenomenological model describing the evolution of the flow stress as a function of the dislocation density. The applied model allowed establishing a correlation between the strain hardening curvature and the size of microstructural features controlling the dislocation multiplication. The obtained results demonstrated that plastic deformation was controlled by the resistance of the low angle grain boundaries below 1000 °C and the high angle grain boundaries at 1500 °C and above. The experimental results obtained at different loading rates showed that thermal activation was essential for the passage of dislocations through grain boundary interfaces at 1000 °C and above. The limitations of the applied model and need for further development of the physical model accounting for stress- and temperature-induced grain growth are discussed.

  18. The computer-aided hot-forging simulation of P/M connecting rods

    Science.gov (United States)

    Jinka, Ashoka G. K.

    1995-08-01

    Computer-aided engineering simulation techniques using a computational method are increasingly being applied to the simulation of powder metallurgy (P/M) component processing. This emerging area of applied research in the P/M industry offers the promise of a cheaper and more reliable route to part design, analysis, and development. In order to meet this goal, simulation tools that take into account the physics and mechanics of the deformation process have to be developed. This article reports one such simulation procedure as applied to the hot forging of a P/M connecting rod on a three-dimensional model. This review focuses briefly on the development of a new model, which in the study is basedon the finite-element method. Thestudy brings out a perspective for understanding the mechanical behavior of the porous material within the scope of a P/M industrial component such as a connecting rod.

  19. Inner-product of strain rate vector through direction cosine in coordinates for disk forging

    Institute of Scientific and Technical Information of China (English)

    ZHAO De-wen; JIN Wen-zhong; WANG Lei; LIU Xiang-hua

    2006-01-01

    A new linear integration for plastic power was proposed. The effective strain rate for disk forging with bulge was expressed in terms of two-dimensional strain rate vector, and then its direction cosines were determined by the ratio of coordinate increments. Furthermore, inner-product of the vector for plastic power was term integrated by term and summed. Thereafter, through a formula for determination of bulge an analytical solution of stress effective factor was obtained. Finally, through compression tests, the calculated results of above formula were compared with those of Avitzur's approximate solution and total indicator readings of the testing machine. It is indicated that the calculated compression forces are basically in agreement with the measured ones if the pass reduction is less than 13.35%.However, when the reduction gets up to 25.34% and 33.12%, the corresponding errors between the calculated and measured results also get up to 6% and 13.5%, respectively.

  20. Some Aspects of Hot Forging Characteristics Of Sintered Ultra – High Strength Ring Preforms

    Directory of Open Access Journals (Sweden)

    Sunil Pandey

    2016-07-01

    Full Text Available Present investigation pertains to assess the hot upset mode of forging characteristics of sintered P/M ring preforms of iron and AISI 4340 P/M steels containing 0.80, 1.20 and 1.60 percent chromium. P/M rings of iron and AISI 4340 grade of blended powders were prepared using suitable die set assembly on a 1.0 MN capacity hydraulic press. The ring geometries were aintained to outer Diameter: Inner Diameter: Height:: 8:4:2 and density in the range of 86 ±1 per cent of theoretical by employing controlled pressure in the range of 480 ±10 MPa and taking pre-weighed powders. These ring preforms were coated with indigenously developed ceramic coating to protect them against oxidation during sintering. These preforms were sintered in an electric muffle furnace at 11500 ±100C for a period of 100 minutes and subsequently hot upset forged to different height strain levels and quenched in linseed oil. Residual ceramic coating was gently machined off followed by dimensional and density measurements. Analysis of the experimental data has revealed that the rate of densification followed the second order polynomial of the form: Y = a0 + a1X + a2X 2; Where, Y = fractional theoretical density achieved, i.e., (ρf/ρth, X = the fractional height deformation. The values of „a0‟, „a1‟ and „a2‟ were dependent upon the composition. Further, the effect of chromium content in AISI 4340 steel was negligibly small on the relationship between per cent decrease in I.D. and the per cent height reduction.

  1. FEM simulation for cold press forging forming of the round-fin heat sink

    Science.gov (United States)

    Wang, Kesheng; Han, Yu; Zhang, Haiyan; Zhang, Lihan

    2013-05-01

    In this paper, the finite element method is used to investigate the forming process of cold press forging for the round-fin heat sink in the automotive lighting. A series of simulations on the round-fin heat sink forming using the program DEFORM were carried out. The blank thickness and friction coefficient on the formation of round-fin were studied, and the tooling structure with counterpressure on the heat sink formation was also investigated. The results show that the blank thickness is very good for the round-fin formation, and the thicker the blank is, the better the round-fin can be formed; and also When both the punch-blank interface and the die-blank interface have the same value of friction factor, the larger value of friction factor is in favor of round-fin forming, the further investigation reveals that the friction at the punch-blank interface has more significant effect on preventing the initiation of flow-through compared with the friction at the die-blank interface, which implies that the punch-blank interface has more significant effect on the material flow in the formation of round-fin. Meanwhile, The tooling structure with counterpressure is helpful to the formation of round-fin heat sink, which not only ensures the height of each round-fin on the heat sink is uniform but also retards the initiation of flow-through on the reverse side of round-fin. In addition, the experiments of press forging process were conducted to validate the finite element analysis, and the simulation results are in good agreement with the experimental data.

  2. Adsorption of hydrogen in titanium

    International Nuclear Information System (INIS)

    In this work the absorption of hydrogen in titanium plates using a constant volume system has been realized. The changes of temperature and pressure were used to monitor the progress of the absorption. A stainless steel vacuum chamber with volume of 4,333 cm3 was used. A titanium sample of 45 x 5.4 x 0.3 cm was located in the center of the chamber. The sample was heated by an electrical source connected to the system. The sample was preconditioned with a vacuum-thermal treatment at 10-6 mbar and 800 Centigrade degrees for several days. Absorption was observed at room temperature and also at higher temperatures. The room temperature absorption was in the pressure range of 1.0 x 103 to 2.5 x 103 mbar, and other absorptions were from 180 to 630 Centigrade degrees at 3.5 x 10-1 to 1.3 x 103 mbar. It was found that the gas absorbed was function of the vacuum-thermal pre-conditioned treatment, pressure and temperature. When the first absorption was developed, additional absorptions were realized in short time. We measured the electrical resistivity of the sample in the experiments but we could not see important changes due to the absorption. (Author)

  3. Impaction grafting in the femur in cementless modular revision total hip arthroplasty: a descriptive outcome analysis of 243 cases with the MRP-TITAN revision implant

    Directory of Open Access Journals (Sweden)

    Wimmer Matthias D

    2013-01-01

    .1% after 8.7 years]. Radiologic evaluation showed no significant change in axial implant migration (4.3% vs. 9.3%; p = 0.19 but a significant reduction in proximal stress shielding (5.7% vs. 17.9%; p  Conclusion We present the largest analysis of the impaction grafting technique in combination with cementless distal diaphyseal stem fixation published so far. Our data provides initial evidence of improved bone regeneration after graft augmentation of metaphyseal bone defects. The data suggests that proximal metaphyseal graft augmentation is beneficial for large metaphyseal bone defects (Paprosky types IIC and III and stem diameters of 17 mm and above. Due to the limitations of a retrospective and descriptive study the level of evidence remains low and prospective trials should be conducted.

  4. 自由锻造液压机的技术现状及设计分析%Technique status and design analysis of free forging hydraulic press

    Institute of Scientific and Technical Information of China (English)

    谢广玉; 李秀珠; 胡海燕

    2013-01-01

    阐述了自由锻造液压机的发展过程和我国锻造压机的技术现状,对自由锻造液压机的几种结构型式和传动方式进行了比较,说明了锻造油压机的技术特点.%The developing process of free forging hydraulic press and technique status in China has been described in the text. Several structural modes and transmission modes of free forging hydraulic press have been compared, and the technical characteristics of forging hydraulic press have been introduced.

  5. Electron beam melting of sponge titanium

    International Nuclear Information System (INIS)

    Fundamental investigations were done on electron beam (EB) melting of sponge titanium by using 80 kW EB melting furnace. Results obtained are as follows: (1) To increase the melting yield of titanium in EB melting of sponge titanium, it is important to recover splashed metal by installation of water-cooled copper wall around the hearth and to decrease evaporation loss of titanium by keeping the surface temperature of molten metal just above the melting temperature of titanium without local heating. (2) Specific power consumption of drip melting of pressed sponge titanium bar and hearth melting of sponge titanium are approximately 0.9 kWh/kg-Ti and 0.5-0.7 kWh/kg-Ti, respectively. (3) Ratios of the heat conducted to water-cooled mould in the drip melting and to water-cooled hearth in the hearth melting to the electron beam input power are 50-65% and 60-65%, respectively. (4) Surface defects of EB-melted ingots include rap which occurs when the EB output is excessively great, and transverse cracks when the EB output is excessively small. To prevent surface defects, the up-down withdrawal method is effective. (author)

  6. Mechanical properties and fracture of titanium hydrides

    International Nuclear Information System (INIS)

    Titanium hydrides tend to suffer fracture when their thicknesses reach a critical thickness. Morphology and mechanical property of the hydrides are, however, not well known. The study aims to reveal the hydride morphology and fracture types of the hydrides. Chevron shaped plate hydrides were found to be produced on the surface of pure titanium (Grade 1) and Grade 7 titanium absorbing hydrogen. There were tree types of fracture of the hydrides, i.e., crack in hydride layer, exfoliation of the layer and shear-type fracture of the hydride plates, during the growth of the hydrides and deformation. We next estimated the true stress-strain curves of the hydrides on Grade 1 and 7 titanium using the dual Vickers indentation method, and the critical strain causing the Mode-I fine crack by indentation. Fracture strength and strain of the hydrides in Grade 1 titanium were estimated as 566 MPa and 4.5%, respectively. Those of the hydride in Grade 7 titanium were 498 MPa and 16%. Though the fracture strains estimated from the plastic instability of true stress-strain curves were approximately the half of those estimated by finite element method, the titanium hydrides were estimated to possess some extent of toughness or plastic deformation capability. (author)

  7. Titanium Coating of the Boston Keratoprosthesis

    Science.gov (United States)

    Salvador-Culla, Borja; Jeong, Kyung Jae; Kolovou, Paraskevi Evi; Chiang, Homer H.; Chodosh, James; Dohlman, Claes H.; Kohane, Daniel S.

    2016-01-01

    Purpose We tested the feasibility of using titanium to enhance adhesion of the Boston Keratoprosthesis (B-KPro), ultimately to decrease the risk of implant-associated complications. Methods Cylindrical rods were made of poly(methyl methacrylate) (PMMA), PMMA coated with titanium dioxide (TiO2) over a layer of polydopamine (PMMATiO2), smooth (Ti) and sandblasted (TiSB) titanium, and titanium treated with oxygen plasma (Tiox and TiSBox). Topography and surface chemistry were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Adhesion force between rods and porcine corneas was measured ex vivo. Titanium sleeves, smooth and sandblasted, were inserted around the stem of the B-KPro and implanted in rabbits. Tissue adhesion to the stem was assessed and compared to an unmodified B-Kpro after 1 month. Results X-ray photoelectron spectroscopy demonstrated successful deposition of TiO2 on polydopamine-coated PMMA. Oxygen plasma treatment did not change the XPS spectra of titanium rods (Ti and TiSB), although it increased their hydrophilicity. The materials did not show cell toxicity. After 14 days of incubation, PMMATiO2, smooth titanium treated with oxygen plasma (Tiox), and sandblasted titanium rods (TiSB, TiSBox) showed significantly higher adhesion forces than PMMA ex vivo. In vivo, the use of a TiSB sleeve around the stem of the B-KPro induced a significant increase in tissue adhesion compared to a Ti sleeve or bare PMMA. Conclusions Sandblasted titanium sleeves greatly enhanced adherence of the B-KPro to the rabbit cornea. This approach may improve adhesion with the donor cornea in humans as well. Translational Relevance This approach may improve adhesion with donor corneas in humans. PMID:27152247

  8. Corrosion behaviour and galvanic coupling of titanium and welded titanium in LiBr solutions

    International Nuclear Information System (INIS)

    Corrosion resistance and galvanic coupling of Grade 2 commercially pure titanium in its welded and non-welded condition were systematically analyzed in LiBr solutions. Galvanic corrosion was evaluated through two different methods: anodic polarization (according to the Mixed Potential Theory) and electrochemical noise (using a zero-resistance ammeter). Samples have been etched to study the microstructure. The action of lithium chromate as corrosion inhibitor has been evaluated. Titanium and welded titanium showed extremely low corrosion current densities and elevated pitting potential values (higher than 1 V). The results of both methods, anodic polarization and electrochemical noise, showed that the welded titanium was always the anodic element of the pair titanium-welded titanium, so that its corrosion resistance decreases due to the galvanic effect

  9. DEVELOPMENT OF OXIDATION RESISTANT TITANIUM ALLOYS BY NIOBIUM ADDITION

    OpenAIRE

    Ackland, Graeme; Siemers, Carsten; Tegner, Bengt E.; Saksl, K.; Brunke, F.; Kohnke, M,

    2014-01-01

    The application of titanium alloys is limited to 550°C due to their poor oxidation resistance. It is known that the addition of niobium improves the oxidation resistance of titanium whereas elements like vanadium do not support titanium’s oxidation behaviour. Hence, the underlying mechanisms are not understood. In the present study, different binary titanium-niobium and titanium-vanadium alloys as well as commercially pure titanium were investigated. Oxidation experiments were carried out at ...

  10. Titanium Oxide: A Bioactive Factor in Osteoblast Differentiation

    OpenAIRE

    Santiago-Medina, P.; Sundaram, P.A.; Diffoot-Carlo, N.

    2015-01-01

    Titanium and titanium alloys are currently accepted as the gold standard in dental applications. Their excellent biocompatibility has been attributed to the inert titanium surface through the formation of a thin native oxide which has been correlated to the excellent corrosion resistance of this material in body fluids. Whether this titanium oxide layer is essential to the outstanding biocompatibility of titanium surfaces in orthopedic biomaterial applications is still a moot point. To study ...

  11. Structure and properties of Titanium for dental implants

    OpenAIRE

    GREGER, Miroslav; Černý, Martin; Kander, Ladislav; Kliber, Jiří

    2009-01-01

    This paper describes manufacture of nano-structural titanium, its structure and properties. Nano-titanium has higher specific strength properties than ordinary (coarse-grained) titanium. Nano-titanium was produced by the equal-channel angular pressing (ETAP) process. The research it self was focused on physical base of strengthening and softening processes and developments occurring at the grain boundaries during the ECAP process at half-hot temperature. Strength of nano-titanium ...

  12. Titanium

    DEFF Research Database (Denmark)

    Fage, Simon W; Muris, Joris; Jakobsen, Stig S;

    2016-01-01

    for detection of type IV hypersensitivity is currently inadequate for Ti. Although several other methods for contact allergy detection have been suggested, including lymphocyte stimulation tests, none has yet been generally accepted, and the diagnosis of Ti allergy is therefore still based primarily on clinical...... evaluation. Reports on clinical allergy and adverse events have rarely been published. Whether this is because of unawareness of possible adverse reactions to this specific metal, difficulties in detection methods, or the metal actually being relatively safe to use, is still unresolved....

  13. Titanium exposure and yellow nail syndrome

    Directory of Open Access Journals (Sweden)

    Ali Ataya

    2015-01-01

    Full Text Available Yellow nail syndrome is a rare disease of unclear etiology. We describe a patient who develops yellow nail syndrome, with primary nail and sinus manifestations, shortly after amalgam dental implants. A study of the patient's nail shedding showed elevated nail titanium levels. The patient had her dental implants removed and had complete resolution of her sinus symptoms with no change in her nail findings. Since the patient's nail findings did not resolve we do not believe titanium exposure is a cause of her yellow nail syndrome but perhaps a possible relationship exists between titanium exposure and yellow nail syndrome that requires further studies.

  14. Current assisted superplastic forming of titanium alloy

    Directory of Open Access Journals (Sweden)

    Wang Guofeng

    2015-01-01

    Full Text Available Current assisted superplastic forming combines electric heating technology and superplastic forming technology, and can overcome some shortcomings of traditional superplastic forming effectively, such as slow heating rate, large energy loss, low production efficiency, etc. Since formability of titanium alloy at room temperature is poor, current assisted superplastic forming is suitable for titanium alloy. This paper mainly introduces the application of current assisted superplastic forming in the field of titanium alloy, including forming technology of double-hemisphere structure and bellows.

  15. Synthesis of Titanium Dioxide Nanocrystals with Controlled Crystal- and Micro-structures from Titanium Complexes

    OpenAIRE

    Makoto Kobayashi; Hideki Kato; Masato Kakihana

    2013-01-01

    Selective synthesis of titanium dioxide (TiO2) polymorphs including anatase, rutile, brookite and TiO2(B) by solvothermal treatment of water-soluble titanium complexes is described with a special focus on their morphological control. The utilization of water-soluble titanium complexes as a raw material allowed us to employ various additives in the synthesis of TiO2. As a result, the selective synthesis of the polymorphs, as well as diverse morphological control, was achieved.

  16. Neutron scattering and models: Titanium

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.B.

    1997-07-01

    Differential neutron elastic-scattering cross sections of elemental titanium were measured from 4.5 {r_arrow} 10.0 MeV in incident energy increments of {approx} 0.5 MeV. At each energy the measurements were made at forty or more scattering angles distributed between {approx} 17 and 160{degree}. Concurrently, differential neutron inelastic-scattering cross sections were measured for observed excitations of 0.975 {+-} 0.034, 1.497 {+-} 0.033, 2.322 {+-} 0.058, 3.252 {+-} 0.043, 3.700 {+-} 0.093, 4.317 {+-} 0.075 and 4.795 {+-} 0.100 MeV. All of the observed inelastically-scattered neutron groups were composites of contributions from several isotopes and/or levels. The experimental results were used to develop energy-average optical, statistical and coupled-channels models.

  17. Corrosion of Titanium Matrix Composites

    Energy Technology Data Exchange (ETDEWEB)

    Covino, B.S., Jr.; Alman, D.E.

    2002-09-22

    The corrosion behavior of unalloyed Ti and titanium matrix composites containing up to 20 vol% of TiC or TiB{sub 2} was determined in deaerated 2 wt% HCl at 50, 70, and 90 degrees C. Corrosion rates were calculated from corrosion currents determined by extrapolation of the tafel slopes. All curves exhibited active-passive behavior but no transpassive region. Corrosion rates for Ti + TiC composites were similar to those for unalloyed Ti except at 90 degrees C where the composites were slightly higher. Corrosion rates for Ti + TiB{sub 2} composites were generally higher than those for unalloyed Ti and increased with higher concentrations of TiB{sub 2}. XRD and SEM-EDS analyses showed that the TiC reinforcement did not react with the Ti matrix during fabrication while the TiB{sub 2} reacted to form a TiB phase.

  18. TC17 Titanium Alloy Disk Forging%TC17钛合金一级轮盘锻造工艺研究应用

    Institute of Scientific and Technical Information of China (English)

    袁士翀; 陈金科; 曾菁; 赵选杰

    2011-01-01

    @@ TC17钛合金是一种富β稳定元素的α+β两相钛合金,其名义成分为Ti-5Al-2Sn-2Zr-4Mo-4Cr,具有高强度、高断裂韧性及高淬透性.美国已成功地将其用于军用和民用航空发动机的压气机盘、风扇盘等零件上.该合金一般在β相区锻造,锻后采用两重退火,从而获得网篮编织α组织,有很高的断裂韧性和蠕变抗力.

  19. Design of New Type of Float Forging Dies for Tractor Gear%新型拖拉机齿轮浮动式锻模设计

    Institute of Scientific and Technical Information of China (English)

    于金伟

    2011-01-01

    The problems in the former forging die of tractor driven cylindrical gears are discussed, a new typed structure of the forging die is proposed, with a float mould core and a float concave die, forging is formed within a closed ring cavity,the forged parts have no burrs, and the spare material is reduced by 80%, the material consumption and the production cost is greatly decreased.%论述了拖拉机圆柱从动齿轮坯原锻模存在的问题,提出了新型锻模结构,锻模采用浮动模芯和浮动凹模结构,锻件在一个封闭环形模腔中成形,锻件无飞边,敷料减少80%,显著降低了材料消耗和生产成本.

  20. Fracture Growth Testing of Titanium 6AL-4V in AF-M315E

    Science.gov (United States)

    Sampson, Jeffrey W.; Martinez, Jonathan; McLean, Christopher

    2015-01-01

    The Green Propellant Infusion Mission (GPIM) will demonstrate the performance of AF-M315E monopropellant in orbit. Flight certification requires a safe-life analysis of the titanium alloy fuel tank to ensure inherent flaws will not cause failure during the design life. Material property inputs for this analysis require testing to determine the stress intensity factor for environmentally-assisted cracking (K (sub EAC)) of Ti 6Al-4V in combination with the AF-M315E monopropellant. Testing of single-edge notched specimens SE(B) representing the bulk tank membrane and weld material were performed in accordance with ASTM E1681. Specimens with fatigue pre-cracks were loaded into test fixtures so that the crack tips were exposed to the monopropellant at 50 degrees Centigrade for a duration of 1,000 hours. Specimens that did not fail during exposure were opened to inspect the crack surfaces for evidence of crack growth. The threshold stress intensity value, KEAC, is the highest applied stress intensity that produced neither a failure of the specimen during the exposure nor showed evidence of crack growth. The threshold stress intensity factor of the Ti 6Al-4V forged tank material when exposed to AF-M315E monopropellant was found to be at least 22.0 kilopounds per square inch. The stress intensity factor of the weld material was at least 31.3 kilopounds per square inch.

  1. Fracture Mechanics Testing of Titanium 6AL-4V in AF-M315E

    Science.gov (United States)

    Sampson, J. W.; Martinez, J.; McLean, C.

    2016-01-01

    The Green Propellant Infusion Mission (GPIM) will demonstrate the performance of AF-M315E monopropellant on orbit. Flight certification requires a safe-life analysis of the titanium alloy fuel tank to ensure inherent processing flaws will not cause failure during the design life of the tank. Material property inputs for this analysis require testing to determine the stress intensity factor for environment-assisted cracking (KEAC) of Ti 6Al-4V in combination with the AF-M315E monopropellant. Testing of single-edge notched, or SE(B), specimens representing the bulk tank membrane and weld material were performed in accordance with ASTM E1681. Specimens with fatigue pre-cracks were loaded into test fixtures so that the crack tips were exposed to AF-M315E at 50 C for a duration of 1,000 hours. Specimens that did not fail during exposure were opened to inspect the crack surfaces for evidence of crack growth. The threshold stress intensity value, KEAC, is the highest applied stress intensity that produced neither a failure of the specimen during the exposure nor showed evidence of crack growth. The threshold stress intensity factor for environment-assisted cracking of the Ti 6Al-4V forged tank material was found to be at least 22 ksivin and at least 31 ksivin for the weld material when exposed to AF-M315E monopropellant.

  2. Evaluation of Stress Corrosion Cracking Susceptibility Using Fracture Mechanics Techniques, Part 1. [environmental tests of aluminum alloys, stainless steels, and titanium alloys

    Science.gov (United States)

    Sprowls, D. O.; Shumaker, M. B.; Walsh, J. D.; Coursen, J. W.

    1973-01-01

    Stress corrosion cracking (SSC) tests were performed on 13 aluminum alloys, 13 precipitation hardening stainless steels, and two titanium 6Al-4V alloy forgings to compare fracture mechanics techniques with the conventional smooth specimen procedures. Commercially fabricated plate and rolled or forged bars 2 to 2.5-in. thick were tested. Exposures were conducted outdoors in a seacoast atmosphere and in an inland industrial atmosphere to relate the accelerated tests with service type environments. With the fracture mechanics technique tests were made chiefly on bolt loaded fatigue precracked compact tension specimens of the type used for plane-strain fracture toughness tests. Additional tests of the aluminum alloy were performed on ring loaded compact tension specimens and on bolt loaded double cantilever beams. For the smooth specimen procedure 0.125-in. dia. tensile specimens were loaded axially in constant deformation type frames. For both aluminum and steel alloys comparative SCC growth rates obtained from tests of precracked specimens provide an additional useful characterization of the SCC behavior of an alloy.

  3. Titanium Heat Pipe Thermal Plane Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Thermacore Inc. proposes an innovative titanium heat pipe thermal plane for passive thermal control of individual cells within a fuel cell stack. The proposed...

  4. Advanced Surface Engineering of Titanium Alloys

    Institute of Scientific and Technical Information of China (English)

    H. Dong

    2000-01-01

    Despite their outstanding combination of properties, titanium and its alloys are very susceptible to severe adhesive wear in rubbing with most engineering surfaces and can exhibit poorcorrosion resistance in some aggressive environments. Surface engineering research centred at the University of Birmingham has been focused on creating designer surfaces for titanium components via surface engineering.Great progress has been made recently through the development of such advanced surface engineering techniques as thermal oxidation, palladium-treated thermal oxidation, oxygen boost diffusion and duplex systems.Such advances thus provide scope for designing titanium components for a diversified range of engineering application, usually as direct replacements for steel components. By way of example, some of the successful steps towards titanium designer surfaces are demonstrated. To data, the potential of these advanced technologies has been realised first in auto-sport and off-shore industrials.

  5. Titanium Heat Pipe Thermal Plane Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the Phase II program is to complete the development of the titanium heat pipe thermal plane and establish all necessary steps for production of...

  6. Titanium nitride nanoparticles for therapeutic applications

    DEFF Research Database (Denmark)

    Guler, Urcan; Kildishev, Alexander V.; Boltasseva, Alexandra;

    2014-01-01

    Titanium nitride nanoparticles exhibit plasmonic resonances in the biological transparency window where high absorption efficiencies can be obtained with small dimensions. Both lithographic and colloidal samples are examined from the perspective of nanoparticle thermal therapy. © 2014 OSA....

  7. Corrosion resistance of titanium alloys for dentistry

    International Nuclear Information System (INIS)

    Titanium and its alloys belong to biomaterials which the application scope in medicine increases. Some properties of the alloys, such as high mechanical strength, low density, low Young's modulus, high corrosion resistance and good biotolerance decide about it. The main areas of the application of titanium and its alloys are: orthopedics and traumatology, cardiosurgery, faciomaxillary surgery and dentistry. The results of investigations concerning the corrosion resistance of the technical titanium and Ti6Al14V alloy and comparatively a cobalt alloy of the Vitallium type in the artificial saliva is presented in the work. Significantly better corrosion resistance of titanium and the Ti6Al14V than the Co-Cr-Mo alloy was found. (author)

  8. Effect of Prior and Post-Weld Heat Treatment on Electron Beam Weldments of (α + β) Titanium alloy Ti-5Al-3Mo-1.5V

    Science.gov (United States)

    Anil Kumar, V.; Gupta, R. K.; Manwatkar, Sushant K.; Ramkumar, P.; Venkitakrishnan, P. V.

    2016-06-01

    Titanium alloy Ti5Al3Mo1.5V is used in the fabrication of critical engine components for space applications. Double vacuum arc re-melted and (α + β) forged blocks were sliced into 10-mm-thick plates and subjected to electron beam welding (EBW) with five different variants of prior and post-weld heat treatment conditions. Effects of various heat treatment conditions on the mechanical properties of the weldments have been studied. The welded coupons were characterized for microstructure, mechanical properties, and fracture analysis. An optimized heat treatment and welding sequence has been suggested. Weld efficiency of 90% could be achieved. Weldment has shown optimum properties in solution treated and aged condition. Heat-affected zone adjacent to weld fusion line is found to have lowest hardness in all conditions.

  9. 大锻件锻压工艺及质量控制系统雏形的研究%Research on Forging Process and Original Quality Control System of Heavy Forgings

    Institute of Scientific and Technical Information of China (English)

    齐作玉; 张岗

    2015-01-01

    分析了我国大锻件产品质量长期难以稳定的原因。研究设计了大锻件锻压工艺及质量控制系统的雏形,介绍了系统设计原理和系统主要结构及组成。该系统解决了传统上工艺设计数据、生产操作数据和质量检验数据难以查询、关联、积累和分析的问题。%The reason that the quality of heavy forgings in China is difficult to maintain stable in a long time has been analyzed.The forging process and the original quality control system of heavy forgings have been researched. Meanwhile, the design principle and the main structure and composition for system have been introduced.The tradi-tional problems for process design data, production operation data and quality inspection data, which are difficult to inquire, relate, accumulate and analyze, have been solved.

  10. Titanium dioxide nanoparticles: Occupational exposure limits

    OpenAIRE

    Anna Maria Świdwińska-Gajewska; Sławomir Czerczak

    2014-01-01

    Titanium dioxide (TiO2) is produced in Poland as a high production volume chemical (HPVC). It is used mainly as a pigment for paints and coatings, plastics, paper, and also as additives to food and pharmaceuticals. Titanium dioxide nanoparticles are increasingly applied in cosmetics, textiles and plastics as the ultraviolet light blocker. This contributes to a growing occupational exposure to TiO2 nanoparticles. Nanoparticles are potentially responsible for the most adverse effects of titaniu...

  11. Functional studies of calcium enriched titanium surfaces.

    OpenAIRE

    Mihoc, R. I.

    2007-01-01

    There exists a clinical requirement for dental implants which will enhance the speed of achievement of osseointegration, its maintenance, and biological and physical properties. Whilst commercially pure titanium remains the material of choice for implant fabrication, a promising approach to enhancing its performance is the surface incorporation of metallic ions, or alkali modification of titanium. Osteoblast behaviour adjacent to the implant is a key factor in osseointegration and it is known...

  12. Microstructure and Slip Character in Titanium Alloys

    OpenAIRE

    Banerjee, D.; Williams, J. C.

    1986-01-01

    Influence of microstructures in titanium alloys on the basic parameters of deformation behaviour such as slip character, slip length and slip intensity have been explored. Commercial titanium alloys contain the hexagonal close packed (alpha) and body centred cubic (bita) phases. Slip in these individual phases is shown to be dependent on the nature of alloying elements through their effect on phase stability as related to decomposition into ordered or w structures. When alpha and bita coexist...

  13. TEFLON VS TITANIUM PROSTHESES IN STAPES SURGERY

    OpenAIRE

    Rajesh Vishwakarma; Simple Patadia; Pratibha Goswami; Kalpesh Patel; Dipesh Darji

    2014-01-01

    BACKGROUND: Otosclerosis is one of the most leading causes of conductive hearing loss with intact tympanic membrane in adults. Stapes prostheses have seen many changes in its shape, design and material. Both Teflon and Titanium prostheses used in this study having different method of application are reviewed in detail. OBJECTIVE: To compare the outcomes of use of Teflon and Titanium prostheses in stapedotomy surgery in patients with conductive hearing loss. STUDY DESIGN: Prospective ...

  14. Backscatter radiation at tissue-titanium interfaces

    International Nuclear Information System (INIS)

    The induced secondary electrons from a metal surface by diagnostic X-rays are thought to contribute to cell damage near the tissue-metal boundaries of metal implants. Titanium implants are becoming increasingly more popular for tissue reconstructions and it is rather often desirable to take radiographs of the operated area. In this study we compared the biological effects of radiation on cultured mammalian test cells grown on titanium plates with the radiation effects on cells that were grown on plastic control plates. In order to study the acute radiation effects on cell growth it was necessary to work with rather high radiation doses (0.7-5 Gy). Photon energies, suitable for diagnostic radiography in odontology, 65 kV, were applied. We found that the cells grown on titanium plates were, in terms of the applied dose in the surrounding culture medium, more sensitive to the irradiations than the cells growing on plastic plates. The survival curve for the cells on titanium had a steeper slope, showed no shoulder in the low-dose region and looked like curves normally obtained for high LET radiation. It was not possible to resolve to what degree the titanium-dependent changes were due to an increased dose near the titanium surface or to a change in the radiobiological effectiveness. Although there was a significant decrease in cellular survival near the metal, postoperative intraoral radiography after titanium implantations need not be excluded. The maximal doses given in odontological X-ray examinations are less than 1 mGy and, if the results in this study are applied, the biological effects near the titanium implant will correspond to biological effects in soft tissue of doses less than 20 mGy which is lower than the doses that give acute effects. The risk of acute healing disturbances are significant only at much higher radiation doses. (orig.)

  15. Comparison of mechanical properties in conventional and small punch tests of fractured anisotropic A350 alloy forging flange

    International Nuclear Information System (INIS)

    Conventional tensile test (CTT) and small punch test (SPT) was carried out on a failed ASTM A350 forging flange to study specimen size effect on mechanical behavior. Specimens were machined from the failed flange along Circumferential and longitudinal directions to study the effect of anisotropy on mechanical properties. Our results show that an optimum sampling has to be used for correlation between SPT and conventional tensile test (CTT). Fractography studies carried out on the failed samples indicate that the fracture modes of SPT samples and the CTT samples were different with the former showing better toughness than the latter. This is attributed to smaller size of the specimen and constraints imposed by the experimental setup. Due to the anisotropy of the forged material, the sampling plane in the SPT should be perpendicular to the load direction for reliable correlation between the results of both methods of testing.

  16. High Pressure in the Inner Wall of Phosphorus Machine Forging Companies%高压内壁除磷机在锻造企业的使用

    Institute of Scientific and Technical Information of China (English)

    孟立社

    2015-01-01

    Forging machine forging diameter pipe diameter forging machine equipment is the trend of development. Trail forging machine forging steel pipe can meet specific process requirements, but also to meet the accuracy requirements. Forged pipe can be effective, depends largely on the handling of phosphorus oxide in the tube sheet. High pressure inside wall function completely phosphorus and phosphorus in automatic condition, and faster, and phosphorus in temperature can be maintained in the range of process requirements.%应用径锻机锻管是径锻机设备发展的趋势。径锻机锻管既可满足特殊的用钢工艺需求,还可满足精度要求。锻管能否奏效,很大程度上取决于管坯内氧化皮磷片的处理情况。高压内壁除磷机能在全自动状况下彻底除磷,且速度较快、除磷中温度可保持在工艺要求的范围之内。

  17. Initial cytotoxicity of novel titanium alloys.

    Science.gov (United States)

    Koike, M; Lockwood, P E; Wataha, J C; Okabe, T

    2007-11-01

    We assessed the biological response to several novel titanium alloys that have promising physical properties for biomedical applications. Four commercial titanium alloys [Super-TIX(R) 800, Super-TIX(R) 51AF, TIMETAL(R) 21SRx, and Ti-6Al-4V (ASTM grade 5)] and three experimental titanium alloys [Ti-13Cr-3Cu, Ti-1.5Si and Ti-1.5Si-5Cu] were tested. Specimens (n = 6; 5.0 x 5.0 x 3.0 mm(3)) were cast in a centrifugal casting machine using a MgO-based investment and polished to 600 grit, removing 250 mum from each surface. Commercially pure titanium (CP Ti: ASTM grade 2) and Teflon (polytetrafluoroethylene) were used as positive controls. The specimens were cleaned and disinfected, and then each cleaned specimen was placed in direct contact with Balb/c 3T3 fibroblasts for 72 h. The cytotoxicity [succinic dehydrogenase (SDH) activity] of the extracts was assessed using the MTT method. Cytotoxicity of the metals tested was not statistically different compared to the CP Ti and Teflon controls (p > 0.05). These novel titanium alloys pose cytotoxic risks no greater than many other commonly used alloys, including commercially pure titanium. The promising short-term biocompatibility of these Ti alloys is probably due to their excellent corrosion resistance under static conditions, even in biological environments. PMID:17385227

  18. TEFLON VS TITANIUM PROSTHESES IN STAPES SURGERY

    Directory of Open Access Journals (Sweden)

    Rajesh Vishwakarma

    2014-04-01

    Full Text Available BACKGROUND: Otosclerosis is one of the most leading causes of conductive hearing loss with intact tympanic membrane in adults. Stapes prostheses have seen many changes in its shape, design and material. Both Teflon and Titanium prostheses used in this study having different method of application are reviewed in detail. OBJECTIVE: To compare the outcomes of use of Teflon and Titanium prostheses in stapedotomy surgery in patients with conductive hearing loss. STUDY DESIGN: Prospective study SETTING: Tertiary referral centre METHODS: A prospective study of 50 patients of otosclerosis, who underwent stapedotomy at B.J.Medical College, Civil Hospital, Ahmedabad, with Teflon/Titanium prostheses, from June 2009-February 2012 was done. Follow up was done for a minimum period of 6 months. Revision cases were excluded. A comparison of prostheses was concluded by differences in AB (Air Bone Gap. RESULT: Postoperative ABG of 20db or less was seen in 96% in both groups. The mean postoperative ABGap was 8.2 dB and 11.5 dB for Teflon and Titanium group respectively. There was no statistically significance difference noted in ABGap between Teflon and Titanium pistons at 95% confidence limit at P<0.05. There was significant improvement of AC thresholds at each frequency except for above 4 kHz, in postoperative period. CONCLUSION: Both prostheses provide equal benefit to patients and there is no statistically significant difference between the uses of Teflon/Titanium prostheses. Long term results are still to be analyzed.

  19. Effect of molybdenum addition on the mechanical properties of sinter-forged Fe–Cu–C alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rathore, Sanjay S., E-mail: rathore.sanjaysingh@gmail.com; Salve, Milind M., E-mail: milindrowling@gmail.com; Dabhade, Vikram V., E-mail: vvdabfmt@iitr.ac.in

    2015-11-15

    Molybdenum provides solid solution strengthening, enhances hardenability and has thus been used to improve mechanical properties of ferrous alloys significantly. The present study reports the effect of molybdenum addition on the properties of sinter-forged Fe–Cu–C alloys prepared using elemental powders under various heat treatment conditions. The elemental powder mixtures were compacted at a pressure of 500 MPa followed by sintering at 1120 °C in N{sub 2}–20%H{sub 2} atmosphere. Further, the sintered compacts were immediately forged at the sintering temperature in a closed die. The sinter-forged compacts were further homogenized and then heat treated under different cooling rates. Enhancement of the mechanical properties (hardness and tensile strength) were observed with Mo addition and increase in severity of quench. Hardness of air cooled samples was slightly lower than that of the water quenched samples but comparable with oil quenched samples. However, no significant increase in hardness was observed beyond 1.5 wt% Mo addition for all cooling conditions. At higher molybdenum content ductility was retained due to stabilization of ferrite phase by molybdenum. The microstructural study showed mostly ferrite–pearlite structure in furnace cooled condition whereas a complex microstructure was observed in the faster cooling conditions. Grain refinement was also observed with molybdenum addition. - Highlights: • Mo (0.25–4.0 wt%) addition in sinter-forged Fe–2Cu–0.65C alloys was investigated. • Effect of heat treatment on mechanical properties and microstructure was discussed. • Hardness and strength increased with Mo addition at the expense of ductility. • Hardness in air cooled condition was comparable with oil/water cooled conditions.

  20. Effect of molybdenum addition on the mechanical properties of sinter-forged Fe–Cu–C alloys

    International Nuclear Information System (INIS)

    Molybdenum provides solid solution strengthening, enhances hardenability and has thus been used to improve mechanical properties of ferrous alloys significantly. The present study reports the effect of molybdenum addition on the properties of sinter-forged Fe–Cu–C alloys prepared using elemental powders under various heat treatment conditions. The elemental powder mixtures were compacted at a pressure of 500 MPa followed by sintering at 1120 °C in N2–20%H2 atmosphere. Further, the sintered compacts were immediately forged at the sintering temperature in a closed die. The sinter-forged compacts were further homogenized and then heat treated under different cooling rates. Enhancement of the mechanical properties (hardness and tensile strength) were observed with Mo addition and increase in severity of quench. Hardness of air cooled samples was slightly lower than that of the water quenched samples but comparable with oil quenched samples. However, no significant increase in hardness was observed beyond 1.5 wt% Mo addition for all cooling conditions. At higher molybdenum content ductility was retained due to stabilization of ferrite phase by molybdenum. The microstructural study showed mostly ferrite–pearlite structure in furnace cooled condition whereas a complex microstructure was observed in the faster cooling conditions. Grain refinement was also observed with molybdenum addition. - Highlights: • Mo (0.25–4.0 wt%) addition in sinter-forged Fe–2Cu–0.65C alloys was investigated. • Effect of heat treatment on mechanical properties and microstructure was discussed. • Hardness and strength increased with Mo addition at the expense of ductility. • Hardness in air cooled condition was comparable with oil/water cooled conditions

  1. Simulations and Experiments of Hot Forging Design and Evaluation of the Aircraft Landing Gear Barrel Al Alloy Structure

    Science.gov (United States)

    Ram Prabhu, T.

    2016-04-01

    In the present study, the hot forging design of a typical landing gear barrel was evolved using finite element simulations and validated with experiments. A DEFORM3D software was used to evolve the forging steps to obtain the sound quality part free of defects with minimum press force requirements. The hot forging trial of a barrel structure was carried out in a 30 MN hydraulic press based on the simulation outputs. The tensile properties of the part were evaluated by taking samples from all three orientations (longitudinal, long transverse, short transverse). The hardness and microstructure of the part were also investigated. To study the soundness of the product, fluorescent penetrant inspection and ultrasonic testing were performed in order to identify any potential surface or internal defects in the part. From experiments, it was found that the part was formed successfully without any forging defects such as under filling, laps, or folds that validated the effectiveness of the process simulation. The tensile properties of the part were well above the specification limit (>10%) and the properties variation with respect to the orientation was less than 2.5%. The part has qualified the surface defects level of Mil Std 1907 Grade C and the internal defects level of AMS 2630 Class A (2 mm FBh). The microstructure shows mean grain length and width of 167 and 66 µm in the longitudinal direction. However, microstructure results revealed that the coarse grain structure was observed on the flat surface near the lug region due to the dead zone formation. An innovative and simple method of milling the surface layer after each pressing operation was applied to solve the problem of the surface coarse grain structure.

  2. Requirements for forged and cast valves and pump casings for nuclear power plants - two ways to basic safety

    International Nuclear Information System (INIS)

    The concept of basic safety poses great requirements for the design, construction, selection of material and manufacture of components. The conversion of this concept into practice requires measures specific to these components. Similar components which are made by different processes of manufacture (forging, casting) require different methods. The suppliers of the valve industry must decide which method should be used to achieve the common aim of 'basic safety'. (orig.)

  3. Effect of the precursor powders on the final properties of hot-forged Bi2223 textured discs

    International Nuclear Information System (INIS)

    The effect of precursor powder assemblage on the phase formation, crystallite orientation and transport critical current density of Bi2223 textured discs has been studied. We observe that starting powder composed of Bi2212 and secondary phases results in a stronger grain alignment than if composed of nearly pure Bi2223. SEM observations and XRD analyses show that the liquid phase produced during the sinter-forging step is essential to achieve sharp orientation distributions and high critical current densities

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

    OpenAIRE

    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...

  5. 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.

  6. For liberty, bread, and love: Annie Buller, Beckie Buhay, and the forging of communist militant femininity in Canada, 1918 - 1939

    OpenAIRE

    Toews, Anne Frances

    2009-01-01

    During the interwar years, friends Annie Buller and Beckie Buhay established careers with the Communist Party of Canada and forged a uniquely Communist militant femininity that led to their eventual canonization by the Party as ideal comrades. Using a biographical approach to women’s working-class history, this thesis examines these women’s significant contributions to the CPC’s political project as gendered work. It also demonstrates that although their representation of themselves as comrad...

  7. Study on the mechanical behaviour of the cold forged niobium as function of the cross section reduction

    International Nuclear Information System (INIS)

    This work aims to study he mechanical behaviour of commercially pure niobium (99.8 % purity) obtained by means of aluminothermic reduction followed by electron beam melting and refining. Eleven groups of specimens were analyzed under tensile tests, with different degrees of reduction (cold working), using rotary forging. Significant alterations were observed in the mechanical properties in all processing steps. Using electron scanning microscopy, the main characteristics of the fracture surface were studied. (author)

  8. Memories of Empire: Amateur Film and Displacement in Péter Forgács's Looming Fire

    OpenAIRE

    Beatriz Rodovalho

    2015-01-01

    Through the analysis of the installation Looming Fire – Stories From the Netherlands East Indies (Péter Forgács, 2013), this article investigates the new meanings mobilized by the reappropriation of amateur films produced in the heyday of the colonial exploitation of the Dutch East Indies, territory which today constitutes Indonesia. As these private records assume new territories of history and memory, we propose to study their various displacements. Along with films which reappropriate offi...

  9. Ultrasonic Defect Characterization in Heavy Rotor Forgings by Means of the Synthetic Aperture Focusing Technique and Optimization Methods.

    Science.gov (United States)

    Fendt, Karl T; Mooshofer, Hubert; Rupitsch, Stefan J; Ermert, Helmut

    2016-06-01

    Ultrasonic nondestructive testing of steel forgings aims at the detection and classification of material inhomogeneities to ensure the components fitness for use. Due to the high price and safety critical nature of large forgings for turbomachinery, there is great interest in the application of imaging algorithms to inspection data. However, small flaw indications that cannot be sufficiently resolved have to be characterized using amplitude-based quantification. One such method is the distance gain size method, which converts the maximum echo amplitudes into the diameters of penny-shaped equivalent size reflectors. The approach presented in this contribution combines the synthetic aperture focusing technique (SAFT) with an iterative inversion scheme to locate and quantify small flaws in a more reliable way. Ultrasonic inspection data obtained in a pulse-echo configuration are reconstructed by means of an Synthetic Focusing Technique (SAFT). From the reconstructed data, the amount and approximate location of small flaws are extracted. These predetermined positions, along with the constrained defect model of a penny-shaped crack, provide the initial parametrization for an elastodynamic simulation based on the Kirchhoff approximation. The identification of the optimal parameter set is achieved through an iteratively regularized Gauss-Newton method. By testing the characterization method on a series of flat-bottom holes under laboratory conditions, we demonstrate that the procedure is applicable over a wide range of defect sizes. To show suitability for large forging inspection, we additionally evaluate the inspection data of a large generator shaft forging of 0.6-m diameter. PMID:27116736

  10. New process with central regenerators for simultaneous energy-saving and reduction of the release of NOx in forging furnaces

    International Nuclear Information System (INIS)

    The work of this research is being carried out as a joint project by Edelstahlwerke Buderus AG and the Operating Research Institute, the VDEL Institute for Applied Research. The preconditions for sensible and ecologically required use of the flow of waste heat on forging furnaces is to be examined by the use of central regenerators. One assumes that with the aid of central regenerators one can achieve double the heat recovery from the waste gas, compared to recuperative processes. (orig.)

  11. Contribution to the history of technology and weaponry: experimental forging of arrowheads using ancient iron bars

    Directory of Open Access Journals (Sweden)

    Renoux, Guillaume

    2009-12-01

    Full Text Available This study is devoted to experiments for defining the forging conditions of roman iron ingots (bars; its purpose is to obtain various arrow heads similar to those issued from the famous site of Uxellodunum (Le Puy d’Issolud, Lot, the last fight of Caesar in Gaul. The main part of work is realized with currency bars found in loads of roman shipwrecks, in Mediterranean Sea, near Les Saintes-Maries-de-la-Mer; two smaller bars are issued from the Pyrenean site of Le Couperé, near Saint-Bertrand-de-Comminges. Effects of the various parameters of forging conditions on metal are analyzed by optical microscopy; they let to reach the different typologies and microstructural features observed with antique arrow heads.

    Cette étude porte sur la recherche des conditions de forgeage optimales ayant conduit à la réalisation de pointes de flèche diverses, identiques à celles dont on dispose pour l’époque antique, parfois en grande abondance, comme cela est le cas pour le site du siège d’Uxellodunum, au Puy d’Issolud (Lot. L’expérimentation a été conduite avec le concours d’un taillandier spécialiste de la restitution d’armes anciennes. L’originalité du travail porte sur le choix du forgeage de barres archéologiques issues des épaves gisant au large des Saintes-Maries-de-la-Mer, en Méditerranée, et des fouilles du Couperé à Saint Bertrand de Comminges, dans les Pyrénées. La caractérisation métallographique préalable de ces barres nous a permis de suivre l’incidence des conditions de forgeage sur la microstructure des pointes de flèche réalisées. Les principaux faciès typologiques et microstructuraux des flèches antiques ont été reproduits, permettant ainsi d’affiner la connaissance technique du protocole de forgeage du fer, au début de notre ère.

  12. Effect of Nano-Scale and Micro-Scale Yttria Reinforcement on Powder Forged AA-7075 Composites

    Science.gov (United States)

    Joshi, Tilak C.; Prakash, U.; Dabhade, Vikram V.

    2016-05-01

    The present investigation deals with the development of AA-7075 metal matrix composites reinforced with nano yttria particles (0.1 to 3 vol.%) and micron yttria particles (1 to 15 vol.%) by powder forging. Matrix powders (AA-7075) and reinforcement powders (yttria) were blended, cold compacted, sintered under pure nitrogen, and finally hot forged in a closed floating die. The hot forged samples were artificially age hardened at 121 °C for various time durations to determine the peak aging time. The mechanical properties in the peak-aged condition as well as density and microstructure were determined and correlated with the reinforcement size and content. The nano composites exhibited a well-densified structure as well as better hardness and tensile/compressive strength as compared to micro-scale composites. The mechanical properties in nano-scale composites peaked at 0.5 vol.% yttria addition while for micro-scale composites these properties peaked at 5 vol.% yttria addition.

  13. Effect of solution treatment on the fatigue behavior of an as-forged Mg-Zn-Y-Zr alloy

    Science.gov (United States)

    Wang, S. D.; Xu, D. K.; Wang, B. J.; Han, E. H.; Dong, C.

    2016-04-01

    Through investigating and comparing the fatigue behavior of an as-forged Mg-6.7Zn-1.3Y-0.6Zr (wt.%) alloy before and after solid solution treatment (T4) in laboratory air, the effect of T4 treatment on fatigue crack initiation was disclosed. S-N curves illustrated that the fatigue strength of as-forged samples was 110 MPa, whereas the fatigue strength of T4 samples was only 80 MPa. Observations to fracture surfaces demonstrated that for as-forged samples, fatigue crack initiation sites were covered with a layer of oxide film. However, due to the coarse grain structure and the dissolution of MgZn2 precipitates, the activation and accumulation of {10–12} twins in T4 samples were much easier, resulting in the preferential fatigue crack initiation at cracked twin boundaries (TBs). Surface characterization demonstrated that TB cracking was mainly ascribed to the incompatible plastic deformation in the twinned area and nearby α-Mg matrix.

  14. 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.

  15. Mechanical properties and microstructural evolution of Al 6061 alloy processed by multidirectional forging at liquid nitrogen temperature

    International Nuclear Information System (INIS)

    Highlights: • Al 6061 alloy is multidirectionally forged (MDF) at liquid nitrogen temperature. • Mechanical properties of the MDF samples are investigated. • Microstructural evolution with deformation strains are evaluated. • MDF sample at cryo temperature showed substantial improvement in UTS: 388 MPa. - Abstract: Al–Mg–Si alloy was subjected to multidirectional forging (MDF) at liquid nitrogen temperature (LNT), to cumulative strains of 1.8, 3.6 and 5.4. The deformed microstructures were examined by optical microscopy under polarized light and transmission electron microscopy (TEM). The deformed samples showed the formation of dislocation cells structure with high dislocation density at lower strains. Composite structure consisting of lamellar morphology at deformation bands and equiaxed grain morphology was observed. Significant differences in microstructure of the deformed samples were observed with increasing strain at LNT. At cumulative strain of 5.4, the microstructure shows nearly equiaxed subgrain structure with an average size of 250 nm with high angle grain boundaries. The mechanical properties were studied through Vickers hardness testing machine and tensile tester. The hardness value of MDFed alloy at LNT has increased from 50 Hv to 115 Hv for cumulative strain of 5.4. Tensile strength has increased from 180 MPa to 388 MPa with 4.5% percentage of elongation to failure. The improvement in hardness and tensile strength of forged alloy is attributed to the formation of equiaxed sub-grain structures and the presence of high dislocation density

  16. Dynamic material property of the sinter-forged Cu-Cr alloys with the variation of chrome content

    International Nuclear Information System (INIS)

    Vacuum interrupters are used in various switch-gear components such as circuit breakers, distribution switches, contactors. The electrodes of a vacuum interrupter are manufactured of sinter-forged Cu-Cr material for good electrical and mechanical characteristics. Since the closing velocity is 1∼2m/s and impact deformation of the electrode depends on the strain-rate at the given velocity, the dynamic material property of the sinter-forged Cu-Cr alloy is important to design the vacuum interrupter reliably and to identify the impact characteristics of a vacuum interrupter accurately. This paper is concerned with the dynamic material properties of sinter-forged Cu-Cr alloy for various strain rates. The amount of chrome is varied from 10 wt% to 30 wt% in order to investigate the influence of the chrome content on the dynamic material property. The high speed tensile test machine is utilized in order to identify the dynamic property of the Cu-Cr alloy at the intermediate strain-rate and the split Hopkinson pressure bar is used at the high strain-rate. Experimental results from both the quasi-static and the high strain-rate up to the 5000 /sec are interpolated with respect to the amount of chrome in order to construct the Johnson-Cook and the modified Johnson-Cook model as the constitutive relation that should be applied to numerical simulation of the impact behavior of electrodes

  17. Oxidation resistant coating for titanium alloys and titanium alloy matrix composites

    Science.gov (United States)

    Brindley, William J. (Inventor); Smialek, James L. (Inventor); Rouge, Carl J. (Inventor)

    1992-01-01

    An oxidation resistant coating for titanium alloys and titanium alloy matrix composites comprises an MCrAlX material. M is a metal selected from nickel, cobalt, and iron. X is an active element selected from Y, Yb, Zr, and Hf.

  18. Dissolution of surface oxide layers on titanium and titanium subhydride between 250 and 7000C

    International Nuclear Information System (INIS)

    The surface-sensitive, spectroscopic techniques of Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) have been applied to the study of oxide dissolution on titanium and titanium subhydride. In an earlier study it was shown, using AES, that the rate of oxygen dissolution into titanium increased sharply at about 3500C. These data correlated well with physical property measurements that indicated that at these temperatures an exothermic reaction, corresponding to the reaction of free titanium with atmospheric oxygen, was occurring. In the present study the work has been expanded to include studies of TiH/sub x/ (x = 1.15, 1.62). It has been found that dissolution of the native oxide on titanium subhydride occurs at a substantially higher temperature (about 5000C) than for titanium. It appears that the outward diffusion of hydrogen is inhibiting the inward diffusion of oxygen on the subhydride samples at temperatures below 5000C. Further studies of the dissolution of oxides on titanium at fixed temperatures in the range of 300 to 3500C have shown that there is a semi-logarithmic relationship between the surface oxygen level and the time at temperature. This is in agreement with earlier gravimetric studies on titanium oxidation in this temperature range

  19. Analytical and experimental evaluation of a proposed self-forging fragment munition

    Energy Technology Data Exchange (ETDEWEB)

    Tuft, D.B.; Folsom, E.N.

    1982-12-27

    Analytical and experimental tools have been used to study the formation of a proposed self-forging fragment projectile. The primary objective of this study is the determination of the interior and exterior shape of the fully formed fragment, and to determine if the fragment tumbles in flight. In addition, it is of interest to compare computer predictions to experimental results. An experiment was performed using high speed photography and high-energy flash x-ray radiography to study liner and case motion and projectile formation. Fabrication and assembly tolerances were closely controlled in an effort to eliminate tolerances as a possible source of fragment instability. X-ray film-density contours were analyzed to determine the fully formed fragment interior and exterior shape. Down-range yaw screens showed fragment tumbling in flight. The computed fragment shape was compared to experimental results and it was found that a retaining ring in the computational model near the liner periphery had a significant effect on the final computed fragment shape. With the retaining ring in the computational model and full two-way sliding between all material interfaces, the final computed fragment showed very good agreement with the experiment on both exterior and interior shapes.

  20. Microstructural evolution of a forged TiAl based alloy during heat treatment at subtransus temperature

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Microstmctural evolution of a forged TiA1 based alloy during heat treatment from 1180 ℃ to 1300 ℃ was investigated. The grain sizes of the alpha phases as wel1 as the sizes and the volume fractions of the gamma phases were eval-uated as a function of heat treatment temperature and time. When the alloys are isothermally heat treated at subtransustemperatures, the sizes of gamma phases(Dγ) increase slightly with heat treatment temperature and time and those of al-pha phases(Da) and the volume fractions of gamma phases(γ) vary significantly with holding time in the early stages ofheat treatments, but after heat treatments for 2 h, γ reveal little variations with holding times and Da approach limits,which can be described by Da0 = 0. 65Dγ/γ. Besides, it has been found that the alpha phases in the specimens heattreated at 1 260 ℃ and 1 300 ℃ contain lamellar structures, at low temperatures, however, appear featureless

  1. Analytical and experimental evaluation of a proposed self-forging fragment munition

    International Nuclear Information System (INIS)

    Analytical and experimental tools have been used to study the formation of a proposed self-forging fragment projectile. The primary objective of this study is the determination of the interior and exterior shape of the fully formed fragment, and to determine if the fragment tumbles in flight. In addition, it is of interest to compare computer predictions to experimental results. An experiment was performed using high speed photography and high-energy flash x-ray radiography to study liner and case motion and projectile formation. Fabrication and assembly tolerances were closely controlled in an effort to eliminate tolerances as a possible source of fragment instability. X-ray film-density contours were analyzed to determine the fully formed fragment interior and exterior shape. Down-range yaw screens showed fragment tumbling in flight. The computed fragment shape was compared to experimental results and it was found that a retaining ring in the computational model near the liner periphery had a significant effect on the final computed fragment shape. With the retaining ring in the computational model and full two-way sliding between all material interfaces, the final computed fragment showed very good agreement with the experiment on both exterior and interior shapes

  2. Microstructural, mechanical, corrosion and cytotoxicity characterization of the hot forged FeMn30(wt.%) alloy.

    Science.gov (United States)

    Čapek, Jaroslav; Kubásek, Jiří; Vojtěch, Dalibor; Jablonská, Eva; Lipov, Jan; Ruml, Tomáš

    2016-01-01

    An interest in biodegradable metallic materials has been increasing in the last two decades. Besides magnesium based materials, iron-manganese alloys have been considered as possible candidates for fabrication of biodegradable stents and orthopedic implants. In this study, we prepared a hot forged FeMn30 (wt.%) alloy and investigated its microstructural, mechanical and corrosion characteristics as well as cytotoxicity towards mouse L 929 fibroblasts. The obtained results were compared with those of iron. The FeMn30 alloy was composed of antiferromagnetic γ-austenite and ε-martensite phases and possessed better mechanical properties than iron and even that of 316 L steel. The potentiodynamic measurements in simulated body fluids showed that alloying with manganese lowered the free corrosion potential and enhanced the corrosion rate, compared to iron. On the other hand, the corrosion rate of FeMn30 obtained by a semi-static immersion test was significantly lower than that of iron, most likely due to a higher degree of alkalization in sample surrounding. The presence of manganese in the alloy slightly enhanced toxicity towards the L 929 cells; however, the toxicity did not exceed the allowed limit and FeMn30 alloy fulfilled the requirements of the ISO 10993-5 standard. PMID:26478385

  3. Recent development in ultra heavy section steel forgings for light water reactor components

    International Nuclear Information System (INIS)

    According to the tendency of reactor pressure vessels accompanying the increase of unit power output of light water reactors, the structural steel materials of very large size and thickness are demanded. In this paper, the performance, quality and manufacture of forgings with largest thickness are outlined. The features of reactor pressure vessels are the very large size of the vessels and their components, the very thick walls of shell flanges, and the manufacture of a shell flange and a nozzle belt in one body. Besides, the reduction of weld line and the adoption of assembling by circumferential welding, the reduction of the possibility of cracking in welds, and the improvements in low temperature toughness, high temperature strength and internal properties are required. As an example, the chemical composition, 400 ton ingot, heat treatment, mechanical properties, high temperature strength, and the quality of thick-walled portion of the shell flange for a 1300 MWe KWU type PWRPV are explained, and the NDT temperature is compared with that of the test plate for the HSST project in USA. The technology in this field in Japan is not behind that in foreign countries. (Kako, I.)

  4. Premature failure analysis of forged cold back-up roll in a continuous tandem mill

    International Nuclear Information System (INIS)

    Highlights: → Metal wrapping and strip welding in work/back-up rolls contact zone caused spalling. → MnS inclusion and pore initiated crack which propagated in milling led to spalling. → Retained austenite conversion to α'-martensite accelerated spalling failure. → Needle shaped carbide (Fe,Mo,Cr)7C3, may cause poor service life of back-up roll. -- Abstract: In this paper, premature failure of a forged back-up roll from a continuous tandem mill was investigated. Microstructural evolutions of the spalled specimen and surface of the roll were characterized by optical microscopy, X-ray diffraction, scanning electron microscopy and ferritscopy, while hardness value of the specimen was measured by Vickers hardness testing. The results revealed that the presence of pore and MnS inclusion with spherical and oval morphologies were the main contributing factors responsible for the poor life of the back-up roll. In addition, metal pick up and subsequently strip welding on the surface of the work roll were found as the major causes of failure in work roll which led to spalling occurrence in the back-up roll. Furthermore, relatively high percentage of retained austenite, say 9%, in outer surface of the back-up roll contributed spalling due to conversion of this meta-stable phase to martensite and creation of volume expansion on the outer surface through work hardening during mill campaign.

  5. Investigations of the microstructural response to a cold forging process of the 6082-T6 alloy

    International Nuclear Information System (INIS)

    Highlights: • SEM-EBSD analysis confirms FEM calculations for friction tests. • Towards damage criteria according to Kernel Average Misorientation (KAM) and Grain Orientation Spread (GOS) values. • Cold forging process influences the 6082-T6 alloy microstructure even at low plastic strain. • Effectiveness of MoS2 Lubricant. - Abstract: The microstructure of 6082 aluminium alloy in artificial aged condition was investigated before and after cold forming. The cold forming process was performed at room temperature with and without lubricant. An in depth microstructure investigation has been carried out through electron backscatter diffraction (EBSD) analysis. Different approaches were considered to quantify the plastic strain: the Line Segment Method (LSM) and the study of misorientations trough the Kernel Average Misorientation (KAM), the Grain Orientation Spread (GOS) and the Grain Average Misorientation (GAM). The evidence of intermetallic particles removal from their location during plastic deformation was observed. Values of plastic strain lower than 0.1 did not affect the grain size itself. Nonetheless it induced the development of sub-structures which may lead to the hardening of the alloy

  6. Initiation of fatigue crack growth from artificial defects in forged 316 LNG stainless steel

    International Nuclear Information System (INIS)

    The presence of solidification defects in cast CF8M steels used as elbows in the PWR primary circuit is now widely acknowledged. It is also widely acknowledged that many of these defects remain in components now in service and, in an attempt to identify these, very sophisticated inspection methods are currently being developed. It is also well known that CF8M steels are susceptible to open-quotes in-serviceclose quotes degradation due to thermal embrittlement and because of this other candidate replacement materials are being investigated. One such material is forged 316 LNG stainless. In the present paper, the crack initiation response of solution treated and 316 LNG has been examined as a function of applied R-ratio, temperature and environment. To date, effects of R-ratio and temperature have been established in air whilst the few tests conducted so far in a simulated PWR environment suggest a further deleterious effect. The manufacture of two CF8M steels is now underway in order to study the effects of ageing on initiation behaviour

  7. Processing and properties of superclean ASTM A508 Cl. 4 forgings

    Energy Technology Data Exchange (ETDEWEB)

    Hinkel, A.V.; Handerhan, K.J. [Ellwood City Forge, PA (United States); Manzo, G.J. [Ellwood Group Inc., PA (United States). Steel Division; Simkins, G.P. [Westinghouse Electric Corp., Pittsburgh, PA (United States)

    1988-12-31

    Steels with improved resistance to temper embrittlement are now being produced using ``superclean`` steelmaking technology. This technology involves the use of scrap control, proper electric arc furnace and ladle refining furnace practices to produce steel with very low Mn, Si, P, S and other residual impurities such as Sn, As and Sb. This technology has been applied on a production basis to modified ASTM A508 Cl- 4 material intended for high temperature pressure vessel forgings. Processing and properties of this superclean material are reviewed. In addition, the cleanliness and mechanical properties are compared to conventionally melted A508 Cl. 4 material. The ``superclean`` A508 Cl. 4 mod. was found to meet all specification requirements. In addition, the superclean material was found to possess superior upper shelf CVN properties, a lower FATT{sub 50} and NDTT, along with superior microcleanliness compared to conventional material. Finally, the superclean material was found to be immune to temper embrittlement based on the short-term embrittlement treatments examined.

  8. Forging Hispanic communities in new destinations: A case study of Durham, NC.

    Science.gov (United States)

    Flippen, Chenoa A; Parrado, Emilio A

    2012-03-01

    The Chicago School of urban sociology and its extension in the spatial assimilation model have provided the dominant framework for understanding the interplay between immigrant social and spatial mobility. However, the main tenets of the theory were derived from the experience of pre-war, centralized cities; scholars falling under the umbrella of the Los Angeles school have recently challenged the extent to which they are applicable to the contemporary urban form, which is characterized by sprawling, decentralized, and multi-nucleated development. Indeed, new immigrant destinations, such as those scattered throughout the American Southeast, are both decentralized and lack prior experience with large scale immigration. Informed by this debate this paper traces the formation and early evolution of Hispanic neighborhoods in Durham, NC, a new immigrant destination. Using qualitative data we construct a social history of immigrant neighborhoods and apply survey and census information to examine the spatial pattern of neighborhood succession. We also model the sorting of immigrants across neighborhoods according to personal characteristics. Despite the many differences in urban form and experience with immigration, the main processes forging the early development of Hispanic neighborhoods in Durham are remarkably consistent with the spatial expectations from the Chicago School, though the sorting of immigrants across neighborhoods is more closely connected to family dynamics and political economy considerations than purely human capital attributes. PMID:24482612

  9. Forging School-Scientist Partnerships: A Case of Easier Said than Done?

    Science.gov (United States)

    Falloon, Garry

    2013-12-01

    Since the early 1980s, a number of initiatives have been undertaken worldwide which have involved scientists and teachers working together in projects designed to support the science learning of students. Many of these have attempted to establish school-scientist partnerships. In these, scientists, teachers, and students formed teams engaged in mutually beneficial science-based activities founded on principles such as equal recognition and input, and shared vision, responsibility and risk. This article uses two partnership programmes run by a New Zealand Science Research Institute, to illustrate the challenges faced by scientists and teachers as they attempted to forge meaningful and effective partnerships. It argues that achieving the theorised position of a shared partnership space at the intersection of the worlds of scientists and teachers is problematic, and that scientists must instead be prepared to penetrate deeply into the world of the classroom when undertaking any such interactions. Findings indicate epistemological differences, curriculum and school systems and issues, and teacher efficacy and science knowledge significantly affect the process of partnership formation. Furthermore, it is argued that a re-thinking of partnerships is needed to reflect present economic and education environments, which are very different to those in which they were originally conceived nearly 30 years ago. It suggests that technology has an important role to play in future partnership interactions.

  10. Importance and role of grain size in free surface cracking prediction of heavy forgings

    International Nuclear Information System (INIS)

    The importance and role of grain size in predicting surface cracking of heavy forgings were investigated. 18Mn18Cr0.5N steel specimens with four different grain sizes were tensioned between 900 and 1100 °C at a strain rate of 0.1 s−1. The nucleation sites and crack morphology were analyzed through electron backscatter diffraction analysis, and the fracture morphology was examined using scanning electron microscopy. The nucleation sites were independent of the grain size, and cracks primarily formed at grain boundaries and triple junctions between grains with high Taylor factors. Grains with lower Taylor factors inhibited crack propagation. Strain was found to mainly concentrate near the grain boundaries; thus, a material with a larger grain size cracks more easily because there are fewer grain boundaries. Fine grains can be easily rotated to a lower Taylor factor to further inhibit cracking. The fracture morphology transformed from a brittle to ductile type with a lowering of grain size. At lower temperature, small dimples on the fracture surfaces of specimens with smaller grain sizes were left by single parent grains and the dimple edge was the grain edge. At higher temperature, dimples formed through void coalescence and the dimple edge was the tearing edge. Finally, the relationship between the reduction in area, grain size, and deformation temperature was obtained

  11. Development and Evaluation of Titanium Spacesuit Bearings

    Science.gov (United States)

    Rhodes, Richard; Battisti, Brian; Ytuarte, Raymond, Jr.; Schultz, Bradley

    2016-01-01

    The Z-2 Prototype Planetary Extravehicular Space Suit Assembly is a continuation of NASA's Z-series of spacesuits, designed with the intent of meeting a wide variety of exploration mission objectives, including human exploration of the Martian surface. Incorporating titanium bearings into the Z-series space suit architecture allows us to reduce mass by an estimated 23 lbs per suit system compared to the previously used stainless steel bearing race designs, without compromising suit functionality. There are two obstacles to overcome when using titanium for a bearing race- 1) titanium is flammable when exposed to the oxygen wetted environment inside the space suit and 2) titanium's poor wear properties are often challenging to overcome in tribology applications. In order to evaluate the ignitability of a titanium space suit bearing, a series of tests were conducted at White Sands Test Facility (WSTF) that introduced the bearings to an extreme test profile, with multiple failures imbedded into the test bearings. The testing showed no signs of ignition in the most extreme test cases; however, substantial wear of the bearing races was observed. In order to design a bearing that can last an entire exploration mission (approx. 3 years), design parameters for maximum contact stress need to be identified. To identify these design parameters, bearing test rigs were developed that allow for the quick evaluation of various bearing ball loads, ball diameters, lubricants, and surface treatments. This test data will allow designers to minimize the titanium bearing mass for a specific material and lubricant combination and design around a cycle life requirement for an exploration mission. This paper reviews the current research and testing that has been performed on titanium bearing races to evaluate the use of such materials in an enriched oxygen environment and to optimize the bearing assembly mass and tribological properties to accommodate for the high bearing cycle life for an

  12. Titanium template for scaphoid reconstruction.

    Science.gov (United States)

    Haefeli, M; Schaefer, D J; Schumacher, R; Müller-Gerbl, M; Honigmann, P

    2015-06-01

    Reconstruction of a non-united scaphoid with a humpback deformity involves resection of the non-union followed by bone grafting and fixation of the fragments. Intraoperative control of the reconstruction is difficult owing to the complex three-dimensional shape of the scaphoid and the other carpal bones overlying the scaphoid on lateral radiographs. We developed a titanium template that fits exactly to the surfaces of the proximal and distal scaphoid poles to define their position relative to each other after resection of the non-union. The templates were designed on three-dimensional computed tomography reconstructions and manufactured using selective laser melting technology. Ten conserved human wrists were used to simulate the reconstruction. The achieved precision measured as the deviation of the surface of the reconstructed scaphoid from its virtual counterpart was good in five cases (maximal difference 1.5 mm), moderate in one case (maximal difference 3 mm) and inadequate in four cases (difference more than 3 mm). The main problems were attributed to the template design and can be avoided by improved pre-operative planning, as shown in a clinical case. PMID:25167978

  13. An evaluation of the properties of rotor forgings made from 26NiCrMoV115 steel: Ocena lastnosti izkovkov za rotorje iz jekla 26NiCrMoV115:

    OpenAIRE

    Balcar, Martin; Bažan, Jiří; Fila, Pavel; Kešner, Dušan; Martínek, Ludvík; Němeček, Stanislav; Sochor, Libor; Turecký, Václav

    2008-01-01

    The development and verification of production technology for the rotor forgings of compressors and generators demonstrate the significant effect of the forming of the input ingot on the final properties of the forgings. The measured yield strength and the strength limit show a trend of dependence on the sample's position in the rotor. Significant differences in the longitudinal as well as in the transversal directions over the cross-section of a forging have been found, especially for the tr...

  14. Quantitative Risk Assessment in Titanium Sponge Plant

    Directory of Open Access Journals (Sweden)

    Prasun K. Roy

    2004-10-01

    Full Text Available This pap& presents the quantitative risk assessment for the storage of titanium tetrachloride (TiCl,.It is the major reactant used for the production of titanium in the titanium spongeplant. Titanium tetrachloride readily reacts with moisture, leading to the release of toxic hydrogen chloride (HCI.F ire explosive and toxicity index analysis, and hazard and operability(HAZOP studies for the entire titanium sponge plant were carried out. Based on these studies, the TiCl, storage section was found to be one of the most hazardous sections in the titaniumsponge plant. Fault tree analysis technique has been used to identify the basic events responsible for the top event occurrence, ie, release of HCl due to the hydrolysis of TiCl, upon contactwith moisture in the environment during spillagelleakage of TiCl, from the storage tanks and to calculate its probability. Consequence analysis of the probable scenarios has been carriedout. The risk has been estimated in terms of fatality.and injuries. Based on these results, basic input in the form of recommendations for possible changes in the design and operation of thetitanium sponge plant have been made for the risk management.

  15. Oriented single crystalline titanium dioxide nanowires

    International Nuclear Information System (INIS)

    We report the synthesis of oriented single crystalline titanium dioxide (TiO2) nanowire arrays on titanium foil. The synthesis method relies on the ability to grow single crystal sodium titanate (Na2Ti2O5·H2O) nanowires on titanium foil through a novel alkali hydrothermal growth process. Following growth, the Na2Ti2O5·H2O nanowires are converted to protonated bititanate (H2Ti2O5·H2O) nanowires through an ion-exchange reaction without changing their morphology or crystal structure. Finally, the protonated bititanate nanowires are converted to single crystalline anatase TiO2 nanowires through a topotactic transformation by calcination. These three sequential steps yield a carpet of 2-50 μm long single crystalline nanowires oriented in the [100] direction and primarily normal to the titanium foil. Even longer nanowires can be grown. The single crystal TiO2 nanowire arrays on flexible titanium substrate may be used in photocatalytic and photovoltaic devices such as dye-sensitized solar cells and may enhance their performance by providing fast electron transport. The nanowires can also be used as templates for producing hierarchical nanostructures such as nanowires decorated with nanoparticles on their periphery or nanotubes with walls made of nanoparticles.

  16. Corrosion Inhibition of Titanium in Artificial Saliva Containing Fluoride

    OpenAIRE

    Latifa KINANI; Abdelilah CHTAINI

    2007-01-01

    The objective of this study was to demonstrate the effect of eugenol on the titanium corrosion in artificial saliva enriched with eugenol at different concentration. The corrosion behaviour and titanium surface characterization were investigated by electrochemical measurements and SEM.

  17. Corrosion Inhibition of Titanium in Artificial Saliva Containing Fluoride

    OpenAIRE

    Latifa KINANI; Rachida NAJIH; Abdelilah CHTAINI

    2008-01-01

    The objective of this study was to demonstrate the effect of eugenol on the titanium corrosion in artificial saliva enriched with eugenol at different concentration. The corrosion behaviour and titanium surface characterization were investigated by electrochemical measurements and SEM.

  18. Advances of Titanium Alloys and Its Biological Surface Modification

    Institute of Scientific and Technical Information of China (English)

    XU Ke-wei; HUANG Ping

    2004-01-01

    This paper reviews the past, present and future of surface modification of titanium alloy from the point of view of preparation of hard tissue replacement implants. The development of titanium alloy is also described.

  19. Speciation of titanium in solvent refined coal using SESC - INAA

    International Nuclear Information System (INIS)

    The preasphaltenes (Pa) separated from solvent refined coal (SRC-I) were fractionated by sequential elution solvent chromatography (SESC) on silica column into 10 fractions. Titanium was determined by instrumental neutron activation analysis (INAA), and was found to be concentrated in fractions 7-10. The preasphaltenes form stable complexes with bis (cyclopentadienyl) titanium(IV) dichloride (BTD), cyclopentadienyl titanium(IV) trichloride (CTT) and titanium(IV) oxide bis (acetylacetone) (TOBA). Preasphaltene titanium complexes (Pa-BTD, Pa-CTT, and Pa-TOBA) were fractionated using the SESC scheme, and the concentration of titanium in each fraction was determined. The mechanism for the reaction between titanium complexes (BTD, CTT or TOBA) and Pa was studied, and the existence of titanium phenoxide type complexes in SRC-I was proposed

  20. Silicon nitride coating on titanium to enable titanium-ceramic bonding.

    Science.gov (United States)

    Wang, R R; Welsch, G E; Monteiro, O

    1999-08-01

    Failures that occur in titanium-ceramic restorations are of concern to clinicians. The formation of poorly adhering oxide on titanium at dental porcelain sintering temperatures causes adherence problems between titanium and porcelain, which is the main limiting factor in the fabrication of titanium-ceramic restorations. To overcome this problem a 1-microm thick Si3N4 coating was applied to a titanium surface using a plasma-immersion implantation and deposition method. Such a coating serves as an oxygen diffusion barrier on titanium during the porcelain firings. The protective coating was characterized in the as-deposited condition and after thermal cycling. Cross sections of Ti/Si3N4-porcelain interface regions were examined by various electron microscopy methods and by energy dispersive analysis of X-rays to study the Si3N4 film's effectiveness in preventing titanium oxidation and in forming a bond with porcelain. The experiments have shown that this Si3N4 coating enables significant improvement in Ti-ceramic bonding. PMID:10380005