Ultrasonic Evaluation of Tailored Forming Components

Author(s):  
Florian Pape ◽  
Timm Coors ◽  
Tim Matthias ◽  
Bernd-Arno Behrens ◽  
Gerhard Poll
1978 ◽  
Vol 17 (01) ◽  
pp. 16-23 ◽  
Author(s):  
Ch. L. Zollikofer ◽  
J. Wewerka ◽  
Th. Frank

35 patients with scintigraphically silent thyroid regions without palpable cold nodules were further evaluated by ultrasonography. In 33 cases the sonographic diagnosis was confirmed by other examinations or the clinical course. 2 cases were misinterpreted right at the beginning of our series.The use of ultrasonography in evaluating silent thyroid regions in the totally decompensated autonomous adenoma, in unilateral thyroid aplasia, thyroiditis and hyperthyroidism is shown to be a reliable and valuable supplement to the clinical and radioisotopic evaluation procedures. When differentiating the totally decompensated autonomous adenoma from unilateral thyroid aplasia a stimulation test need not be performed in most cases. Suspected thyroiditis can be confirmed in a simple way. Being a non-invasive evaluation procedure, ultrasonography should be used before performing a needle biopsy.


Author(s):  
Yoshikazu Ohara ◽  
Setsu Yamamoto ◽  
Tsuyoshi Mihara ◽  
Kazushi Yamanaka

2021 ◽  
Vol 15 (2) ◽  
pp. 137-150
Author(s):  
Susanne Elisabeth Thürer ◽  
Anna Chugreeva ◽  
Norman Heimes ◽  
Johanna Uhe ◽  
Bernd-Arno Behrens ◽  
...  

AbstractThe current study presents a novel Tailored Forming process chain developed for the production of hybrid bearing bushings. In a first step, semi-finished products in the form of locally reinforced hollow profiles were produced using a new co-extrusion process. For this purpose, a modular tool concept was developed in which a steel tube made of a case-hardening steel, either C15 (AISI 1015) or 20MnCr5 (AISI 5120), is fed laterally into the tool. Inside the welding chamber, the steel tube is joined with the extruded aluminum alloy EN AW-6082. In the second step, sections from the compound profiles were formed into hybrid bearing bushings by die forging. In order to set the required forming temperatures for each material—aluminum and steel—simultaneously, a tailored heating strategy was developed, which enabled successful die forging of the hybrid workpiece to the desired bearing bushing geometry. Using either of the case-hardening steels in combination with aluminum, this novel process chain made it possible to produce intact hybrid bearing bushings, which showed both macroscopically and microscopically intimate material contact inside the compound zone.


2021 ◽  
Vol 15 (2) ◽  
pp. 177-186
Author(s):  
Caner-Veli Ince ◽  
Anna Chugreeva ◽  
Christoph Böhm ◽  
Fadi Aldakheel ◽  
Johanna Uhe ◽  
...  

AbstractThe demand for lightweight construction is constantly increasing. One approach to meet this challenge is the development of hybrid components made of dissimilar materials. The use of the hybrid construction method for bulk components has a high potential for weight reduction and increased functionality. However, forming workpieces consisting of dissimilar materials requires specific temperature profiles for achieving sufficient formability. This paper deals with the development of a specific heating and cooling strategy to generate an inhomogeneous temperature distribution in hybrid workpieces. Firstly, the heating process boundaries with regard to temperature parameters required for a successful forming are experimentally defined. Secondly, a design based on the obtained cooling strategy is developed. Next a modelling embedded within an electro-thermal framework provides the basis for a numerical determination of admissible cooling rates to fulfil the temperature constraint. Here, the authors illustrate an algorithmic approach for the optimisation of cooling parameters towards an effective minimum, required for applicable forming processes of tailored forming.


1979 ◽  
Vol 134 (4) ◽  
pp. 422-430 ◽  
Author(s):  
Dean T. Yamaguchi ◽  
Frederick Y.L. Lee

2005 ◽  
Vol 490-491 ◽  
pp. 184-189 ◽  
Author(s):  
Farid Belahcene ◽  
Xiaolai Zhou ◽  
Jian Lu

Shot peening is an effective method of improving fatigue performance of machine parts in the industry by producing a thin surface layer of compressive residual stresses that prevents crack initiation and retards crack growth during service. Nondestructive evaluation of the prevailing compressive residual stresses in the shallow subsurface layer is realized by the critically refracted longitudinal (Lcr) waves. This paper presents experimental data obtained on SMAT (surface mechanical attrition treatment) steel alloy S355 sample. Comparative travel-time shows that there are statistically significant differences in treated and untreated specimen. With knowledge of the acoustoelastic constants which are obtained by a test calibration, the experimental data indicates that compressive residual stresses are distributed near subsurface (hundreds of micron). These stress results show that the Lcr technique is efficient for evaluation of residual stresses after the surface treatment.


1977 ◽  
Vol 5 (5) ◽  
pp. 304-306 ◽  
Author(s):  
Barry B. Goldberg ◽  
Jagdish Patel

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