New original method and device for testing aluminum alloys susceptibility for extrusion welding

2018 ◽  
Vol 18 (4) ◽  
pp. 1491-1505 ◽  
Author(s):  
Leśniak Dariusz
Keyword(s):  
Aluminum Alloys ◽  
Original Method ◽  
Extrusion Welding

Weldability Investigations of AlCuMg Alloys for Extrusion Welding

2012 ◽  
Vol 57 (1) ◽  
pp. 7-17 ◽  
Author(s):  
D. Leśniak
Keyword(s):  
Aluminum Alloys ◽  
High Strength ◽  
Original Method ◽  
Die Design ◽  
Special Device ◽  
Welding Stress ◽  
Extrusion Welding ◽  
2024 Alloy ◽  
Wide Range ◽  
High Strength Aluminum Alloys

Weldability Investigations of AlCuMg Alloys for Extrusion Welding The extrusion of hollow shapes from high strength aluminum alloys with the use of porthole dies encounters, in practice, great difficulties, mainly due to the poor weldability of these materials and the high forces needed to conduct the process. In the work, an original method and a special device are presented, which enable to determine the welding conditions of hard deformable aluminum alloys. The main advantage of the proposed method is that it simulates the conditions occurring in the welding chamber of the porthole dies. The weldability tests were performed for the 2024 alloy with extreme contents of Cu and Mg, in a wide range of welding temperatures and pressures. The microstructure and the seam welds' strength were also examined. The welding conditions for 2024 alloy, which allowed for obtaining high-quality seam welds were determined. The parameter describing the ability to weld was defined as the stress necessary for the welding to the yield stress ratio (σw/k) and was determined for the analyzed alloys. The obtained welding stress values will be the basis for the porthole die design.

scholarly journals Estimation of Extrusion Welding Conditions for 6xxx Aluminum Alloys

2020 ◽  
Vol 47 ◽  
pp. 253-260
Author(s):  
Lesniak Dariusz ◽  
Gromek Pawel
Keyword(s):  
Aluminum Alloys ◽  
Extrusion Welding

Analysis of Extrusion Welding Conditions for AlMg Alloys with High Mg Content

2016 ◽  
Vol 682 ◽  
pp. 401-407 ◽  
Author(s):  
Alicja Wojtyna ◽  
Dariusz Leśniak ◽  
Artur Rękas ◽  
Tomasz Latos ◽  
Krzysztof Zaborowski ◽  
...  
Keyword(s):  
Aluminium Alloys ◽  
Original Method ◽  
Die Design ◽  
High Quality ◽  
Weldability Tests ◽  
Welding Stress ◽  
Porthole Die ◽  
Extrusion Welding ◽  
Wide Range ◽  
Mg Content

In the work, an original method and a special modified device is presented enabling to determine welding conditions of hard deformable aluminium alloys. The main advantage of the proposed method is that it simulates conditions occurring in the welding chamber of the porthole dies. The weldability tests were performed for 5754 (3,5% Mg) and 5019 (5,5% Mg) alloys, in a wide range of temperatures and pressures. The microstructure and joints strength were examined. The welding conditions of AlMg alloys that allowed obtaining high-quality joints were determined. The obtained welding stress values will be the basis for extrusion porthole die design.

Analytical Electron Microscopy Study of Second-Phase Particles in 7075 and 7475 Aluminum Alloys

1985 ◽  
Vol 43 ◽  
pp. 348-349
Author(s):  
M. Raghavan ◽  
J. Y. Koo ◽  
J. W. Steeds ◽  
B. K. Park
Keyword(s):  
Aluminum Alloys ◽  
Silicon Oxide ◽  
Analytical Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Partial Substitution ◽  
Second Phase ◽  
X Ray ◽  
Second Phase Particles ◽  
Almost All

X-ray microanalysis and Convergent Beam Electron Diffraction (CBD) studies were conducted to characterize the second phase particles in two commercial aluminum alloys -- 7075 and 7475. The second phase particles studied were large (approximately 2-5μm) constituent phases and relatively fine ( ∼ 0.05-1μn) dispersoid particles, Figures 1A and B. Based on the crystal structure and chemical composition analyses, the constituent phases found in these alloys were identified to be Al7Cu2Fe, (Al,Cu)6(Fe,Cu), α-Al12Fe3Si, Mg2Si, amorphous silicon oxide and the modified 6Fe compounds, in decreasing order of abundance. The results of quantitative X-ray microanalysis of all the constituent phases are listed in Table I. The data show that, in almost all the phases, partial substitution of alloying elements occurred resulting in small deviations from the published stoichiometric compositions of the binary and ternary compounds.

Minimally Invasive Repair of Pectus Excavatum (MIRPE) - The Basel Experience

Swiss Surgery ◽  
2003 ◽  
Vol 9 (6) ◽  
pp. 289-295 ◽  
Author(s):  
Haecker ◽  
Bielek ◽  
von Schweinitz
Keyword(s):  
Minimally Invasive ◽  
Pectus Excavatum ◽  
Pulmonary Function Tests ◽  
Preoperative Evaluation ◽  
Skin Incision ◽  
Original Method ◽  
Restrictive Lung Disease ◽  
Cardiac Compression ◽  
Cardiac Evaluation ◽  
Indications For Operation

Purpose: Minimally invasive repair of pectus excavatum (MIRPE) was first reported in 1998 by D. Nuss. This technique has gained wide acceptance during the last 4-5 years. In the meantime, some modifications of the technique have been introduced by different authors. Our retrospective study reports our own experience over the last 36 months and modifications introduced due to a number of complications. Methods: From 3/2000 to 3/2003, 22 patients underwent MIRPE. Patients median age was 15.5 years (10.7 to 20.3 years). Standardised preoperative evaluation included 3D computerised tomography (CT) scan, pulmonary function tests, cardiac evaluation with electrocardiogram and echocardiography, and photo documentation. Indications for operation included at least two of the following: Haller CT index > 3.2, restrictive lung disease, cardiac compression, progression of the deformity and severe psychological alterations. Results: In 22 patients (2 girls, 20 boys) undergoing MIRPE procedure, a single bar was used in 21 patients and two bars in one boy. Lateral stabilisers were fixed with non resorbable sutures on both sides. Overall, postoperative complications occurred in six patients (27.3%). In two patients (9.1%) a redo-procedure was necessary due to bar displacement. An additional median skin incision was performed in two patients to elevate the sternum. Pneumothorax or hematothorax in two patients resulted in routine use of a chest tube on both sides. Long-term favourable results were noted in all patients. Conclusions: The MIRPE procedure is an effective method with elegant cosmetic results. Modifications of the original method help to decrease the complication rate and to accelerate acquirement of expertise.

Critical Evaluation of Impedance Phlebography for the Diagnosis of Deep Vein Thrombosis

1974 ◽  
Vol 31 (02) ◽  
pp. 273-278
Author(s):  
Kenneth K Wu ◽  
John C Hoak ◽  
Robert W Barnes ◽  
Stuart L Frankel
Keyword(s):  
Deep Vein Thrombosis ◽  
False Positive ◽  
False Negative ◽  
Critical Evaluation ◽  
Original Method ◽  
Vein Thrombosis ◽  
Negative Results ◽  
False Negative Results ◽  
Deep Vein ◽  
Positive Results

SummaryIn order to evaluate its daily variability and reliability, impedance phlebography was performed daily or on alternate days on 61 patients with deep vein thrombosis, of whom 47 also had 125I-fibrinogen uptake tests and 22 had radiographic venography. The results showed that impedance phlebography was highly variable and poorly reliable. False positive results were noted in 8 limbs (18%) and false negative results in 3 limbs (7%). Despite its being simple, rapid and noninvasive, its clinical usefulness is doubtful when performed according to the original method.

Proposal for Objective Evaluation of the Performance of Various Functional APC-resistance Tests in Genotyped Patients

1997 ◽  
Vol 78 (05) ◽  
pp. 1360-1365 ◽  
Author(s):  
G Freyburger ◽  
S Javorschi ◽  
S Labrouche ◽  
P Bernard
Keyword(s):  
Protein S ◽  
Objective Evaluation ◽  
Original Method ◽  
Screening Methods ◽  
Factor Xii ◽  
Factor V ◽  
Likelihood Ratios ◽  
Modified Method ◽  
Apc Resistance ◽  
Two Parameters

SummaryThe aim of the present study was to evaluate the relative performance of five screening methods for APC resistance caused by the factor V:Q506 mutation: the original method Coatest® APC™ Resistance Chromogenix, a modified method using the same reagents but a predilution 1+4 of the plasma in a factor V deficient plasma from Stago (Stago deficient V) or from Chromogenix (V-DEF Plasma), the Coatest® APC™ Resistance V (Chromogenix), and Accelerimat™ from bioMérieux. Normalization was done against a pool of normal plasmas for the methods from Chromogenix. The study included 350 subjects, 219 were genotyped (174 FV:R506R, 42 FV:Q506R, 3 FV:Q506Q) and most of them were assessed by more than one method. Uncertainty in predicting the FV genotype was evaluated by statistical analysis, which provided a way to quantitate the performance of the different diagnostic approaches. Performance of each test was evaluated by its sensitivity, specificity, R.O.C. curves, positive and negative likelihood ratios (LR), and the overall performance was determined by two parameters derived from the LR curves : the maximum LR value obtained at the crossover of the two curves, and the distance between the two curves for LR = 10. Coatest® APC™ Resistance V and Accelerimat™ were proven to be the methods most able to discriminate for factor V:Q506, while normalization was not shown to improve the screening performance. The original method from Chromogenix was confirmed to undergo many influences (factor XII, PAI-1, thrombin- antithrombin complexes, antithrombin III, hematocrit). Although a very good improvement was provided by the newest methods, they were shown to be influenced by protein S and/or factor V levels in the sample plasma.

Electrochemical Impedance Characteristics of Sintered 7075 Aluminum Alloy Under Ssrt Condition

2013 ◽  
Vol 58 (2) ◽  
pp. 505-508 ◽  
Author(s):  
S. Sunada ◽  
N. Nunomura
Keyword(s):  
Aluminum Alloys ◽  
Complex Shape ◽  
Electrochemical Impedance ◽  
Ingot Metallurgy ◽  
View Point ◽  
Corrosion Properties ◽  
Electrochemical Tests ◽  
Impedance Characteristics ◽  
Polarization Test ◽  
Conventional Ingot

Powder metallurgy (P/M) process has the advantage of better formability to fabricate complex shape products without machining and welding. And recently this P/M process has been applied to the production of aluminum alloys. The P/M aluminum alloys thus produced also have received considerable interest because of their fine and homogeneous structure. Many papers have been published on the mechanical properties of the aluminum alloys produced by P/M process while there have been few on their corrosion properties from the view point of electrochemistry. In this experiment, therefore, two kinds of 7075 aluminum alloys prepared by the conventional ingot metallurgy (I/M) process and P/M process were used, I/M material is commercially available. and their corrosion behavior were investigated through the electrochemical tests such as potentiodynamic polarization test, slow rate strain tensile (SSRT) test and electrochemical impedance spectroscopy (EIS) measurement under SSRT test in the corrosion solution and the deionized water.

Sign in / Sign up

Export Citation Format

Share Document