Status of research on the plastomechanical fundamentals of rolling and drawing processes

Among the processes for plastic deformation of steel, rolling of strip, plate, and sections, and drawing of wire, bars, and tubes are of great importance. A survey is given showing to what extent the plastomechanical fundamentals of these forming methods have been developed. Theory is mainly directed towards the calculation of the deformation force and the flow of material. The governing influences are of geometrical, kinematical, thermal, tribological, and material-scientific kind. Starting from the basic equations of continuum mechanics, the mathematical methods of similitude, visioplasticity, energy bounds, elementary plasticity, slip line fields, and finite elements are briefly characterized.     

Multiphase microstructure in steel bars produced by dieless drawing

In the dieless drawing technology the drawing dies are replaced by a heating device, generally by an induction coil. Bars of different cross-sections, round or even rectangular, with varying dimensions along the length can be produced. By using a cooling box in connection with the heating device this deformation process may also be employed for a thermomechanical treatment of steels. The special cooling strategy with low cooling rates at high temperatures (during ferrite formation) and higher cooling rates at lower temperatures favours the formation of multiphase microstructures (ferrite - bainite/martensite) with a low yield strength but a strong work hardening effect. The experiments were carried out on rods with a diameter of 16 mm of a plain low carbon steel (0.1%C, 0.7%Mn). The specimens were locally heated up to the maximum temperature ?_max that initiates the dieless drawing process, and subsequently cooled with different coolants. The change in yield strength and tensile strength and the corresponding change in the ratio of both could be achieved by variation of ?_max and the cooling conditions. The multiphase microstructure with desired mechanical properties was produced at a strain of about more than 0.45 within the region of ?_max ≈ 900–1000°C and a finale cooling rate of about 20 K/s.     

Theoretical and experimental investigations into dieless drawing

Some experimental and theoretical results are presented for the dieless drawing method. Because of the absence of a rigid die considerable flexibility is reached by this method. For example it is possible to achieve very high strains in one pass. Unlike in conventional drawing it is possible to produce parts with variable cross‐sections along the length by varying the drawing velocity appropriately. This is demonstrated theoretically and experimentally. To model this process a simple one‐dimensional disk model is suggested. The resultant temperature distribution is compared with previous calculations.     

Beckmann's Studio Computers Specified for Early Computer Art

When the pioneers of computer art started to produce their works by programming mainframes, using plotters for output, the Austrian sculptor Otto Beckmann took a different path. He used a special computer constructed by his son Oskar Beckmann. This article describes the technical context of early computer art, Beckmann's interdisciplinary team ars intermedia, and the development of nonconventional studio computers.     

Versuchsmethodik für Laboruntersuchungen zum Zusammenhang zwischen Herstellungsbedingungen,Gefüge und Werkstoffeigenschaften

Wegen ihrer großen Bedeutung unter den heutigen Herstellungsverfahren wurden thermomechanische Behandlungen durch Warmflachstauchversuche mit dem Warmumformsimulator (Wumsi) des Max-Planck-Instituts für Eisenforschung durchgeführt. Die gegenüber anderen Simulationsverfahren vergleichsweise großen Wumsi-Proben erlaubten erstmalig mit aus ihnen entnommenen 1/2 CT-Proben auch die Durchführung von Bruchmechanikversuchen an im Labor thermomechanisch behandeltem Stahl. Hierbei wurden die Meßwerte mit einem Laborrechnersystem für die spätere Auswertung gespeichert. Die beschriebene Versuchsmethodik wird exemplarisch mit Versuchsergebnissen an dem Vergütungsstahl 50 CrMo 4 illustriert. Neben einer thermomechanischen Behandlung mit vier simulierten Walzstichen wurde eine konventionelle Vergleichsvariante erzeugt; die Proben wurden bei verschiedenen Temperaturen angelassen. Sowohl bei den Ergebnissen der Zug- und Kerbschlagbiegeversuche, als auch bei den bruchmechanischen Kennwerten Rißzähigkeit K_Ic und J_R-Rißwiderstandskurven zeigte sich die Verbesserung der Werkstoffeigenschaften durch die thermomechanische Behandlung gegenüber denen nach der konventionellen Behandlung.     

Farbmessungen auf dem Gebiete der Lebensmitteluntersuchung

Ohne Zusammenfassungbedeutet mit Abbildungen.     

Ein Beitrag zum Förderprinzip periodisch arbeitender,ventilloser Pumpen

Ohne Zusammenfassung Schlu? des Aufsatzes in Forsch. Ing.-Wes.29 (1963) Nr. 2 S. 47/56.