Das Zeitstandverhalten von Hartblei

The creep properties of hard lead The exact dimensioning of structural elements which are susceptible to creep deformation is acquiring increasing technical importance. A search through the literature (1, 2, 3, 4) for the mechanical properties of hard lead alloys reveals hardly any data on the creep behaviour of these materials. Genuine creep tests extending over prolonged periods are required in order to obtain definitive data on the strength properties of lead and its common engineering alloys. The following discussion reports on the results of creep tests lasting up to 80 000 hours on five types of hard lead.     

Das Zeitstandverhalten der Werkstoffe und die Grundlagen der Hochtemperatur-Plastizität

Creep and Creep-Rupture Behaviour of Materials- and the Fundamentals of High Temperature Plasticity . Principles of evaluation methods for creep data (strain vs. time) for technological purposes as well as in fundamental research. Derivation and discussion of equations representing rupture-life and constant strain curves in creep rupture diagrams. Consequences for extrapolation of short-time tests.     

Zum Einfluß wechselnder Temperaturen auf das Zeitstandverhalten von Nickellegierungen

On the Effect of Alternating Temperatures on the Creep Strength of Nickel Alloys. The design of parts for duty under creep stresses, such as turbine blades, had conventionally been rested on the assumption of linearly accumulating damage in the presence of alternating temperatures. Experimental work on nickel alloys has now shown that the damage will not generally accumulate linearly. Temperature alternations, when superimposed upon creep stresses, will cause multiplicative damage by impairing the creep strength and on occasion substantially promoting creep.     

Zeitstandverhalten von Schweißverbindungen aus HDPE bei der Einwirkung von Chemikalien

Long Term Creep Tests with HDPE Pipes under the Influence of Several Fluids The results of long term creep tests with unwelded and welded HDPE pipes under the influence of several fluids are presented. It is shown that the resistance factors determined by the investigations of tubes are also valid for welded constructions, when the long term weld factors in DVS 2205, Blatt 1 are taken in consideration.     

Das Zeitstandverhalten des Stahles X 10 NiCrAlTi 32 20 bei hohen Temperaturen und langen Zeiten

Creep Behaviour of Steel × 10 NiCrATi 32 20 at Elevated Temperatures and Over Long Periods. The demands made on the quality of materials for chemical plants are continually increasing. Not only has there been a changeover to large units and an increase in the pressures and temperatures employed, but for technical and financial reasons the properties of the materials must be optimally utilized. In components subjected to the highest stresses due to pressure and temperature, the service life has to be calculated with the aid of creep strength characteristics. On the basis of the austenitic material × 10NiCrAlTi 32 20 an attempt is made, with the aid of creep strength characteristics, which have been determined in our own long-time test, to make a statement regarding the structural states existing at defined times and to draw conclusions for the use of this material.     

Beitrag zum Zeitstandverhalten von Titan für die Anwendung im chemischen Apparatebau

Creep Rupture Data of Titanium In a joint investigation program of the Dechema Committee “Werkstoffe und Konstruktion im Chemie-Apparatebau” creep rupture data of titanium Ti1 (DIN materials no. 3.7025) and titanium Ti2 (DIN materials no. 3.7035) were measured in the temperature region of 20 to 300 °C and for periods of up to 50 000 hrs, allowing reliable extrapolation to 100 000 hrs values. The results of these investigations are presented together with earlier results on titanium Ti3 (DIN materials no. 3.7055). The data shown enable the assessment of the behaviour of titanium components even for long service times.     

Das Langzeitverhalten von Metallklebverbindungen

The Long Term Behaviour of Metal bonds Important results fort he prediction of the long term strength of metal bonds are available by measuring the glue-line deformation of mechanical loaded shear-specimens under artifical humid climate. The maximum load is 50% of the shear strength, the testing time needed is 1000 h. It is sufficient to measure the glue line deformation on one point of the overlap-length because differences in other deformation along the glue line are equalized by the plastic deformation capacity of the adhesives.     

Das Diffusionsschweißen von Titanlegierungen

Diffusion Bonding of Titanium Alloys. Diffusion bonding is a 4 stage process involving surface deformation atomic bonding interface diffusion and grain growth. These processes can proceed in the above order or more or less simultaneously. The effect of production parameters and material properties on the basic mechanisms is investigated. Several diffusion bonding techniques for industrial applications have been developed and are discussed in detail. Experience with the diffusion bonding of titanium alloys has shown that base material properties may be obtained in the weld zone. Actual parts fabricated by diffusion bonding sometimes show higher strength than made without welding. Some of the difficulties associated with diffusion bonding are presented. The economical and technical advantages of the diffusion bonding process are shown by reference to typical applications where this technique can be successfully applied.     

Das Verhalten von PVC hart gegen Chemikalieneinwirkung

Behaviour of Unplasticized PVC under Chemical Attack After a general view on the mechanism of chemical attacks to plastic materials, the most important effects to the chemical resistance of unplasticized PVC will be described. The test methods for the determination of chemical resistance are explained, basing on the historical development over 50 years time and the evidence of information. With the aid of some characteristic examples the various mechanism of attack and their influence on uplasticized PVC are described both for immersiontest as well as for long term internal pressure tests and it is shown, that both tests complete each other. A proposal is made for the determination of chemical resistance factors f_CR of unplasticized PVC basing on long term internal pressure tests with acceptable testing times. In consideration of the results of immersion tests it will be possible to give f_CR factors for rigid PVC too, without being forced to wait for the abrupt drop of the characteristic creep strength curve, which is not yet reached after 10⁵ hours, with water at 60 degr. C.     

Das Verhalten von Aluminium-Werkstoffen in der Hausinstallation

The corrosion behaviour of aluminium alloys . The corrosion behaviour of the aluminium alloys AlMgMn, AlMgSi 0,8 and AlZn 1 was investigated at two temperatures in two natural waters with different contents with and without oxygen. These measurements were performed as well separated as in contact with copper, brass, iron and zinc; the electrode potentials and the galvanic currents were measured and registrated. The results of the metallographic investigations concerning pitting corrosion of the aluminium samples and of the measurements under potentiostatic conditions were summarized in especial corrosion diagrams. Out of these the corrosion risks of the aluminium materials can be seen. The investigated aluminium alloys – except AlZn 1 – showed unpolarized a good corrosion resistance. The best of them was AlMgMn. In contact with iron and copper containing alloys aluminium were polarized in anodic direction depending of the different metals and of oxygen content of the water. The limit of the pitting corrosion has been exceeded at times. In the cold waters zinc polarized the aluminium alloys cathodic. References were given for applications of aluminium building parts in the home installation and it was informed about experiences which corresponds with these results.     

Zeitstandverhalten einiger fortschrittlicher Schaufelwerkstoffe für Industriegasturbinen

Creep rupture behaviour of some advanced materials for industrial gas turbines The creep rupture behaviour of three DS-alloys, an ODS-alloy and a PM-alloy for gas turbine blades is investigated up to 20 000 h test duration. Further, the elastoplastic behaviour is determined in tensile tests and the contraction behaviour in long-term annealing tests. On this basis, a characterisation of the strength and partly a modelling of the deformation behaviour of the alloys is given.     

Das Schadensbild bei Kavitations-Korrosion von Reinaluminium Al 99,5

Cavitation-Corrosion – Types of Damage on the Surface of Pure Aluminium . By scanning electron microscope studies the development and propagation of plastic deformation and other types of damage are investigated.     

Das Korrosions- und Spannungsrißkorrosionsverhalten von Aluminium-Konstruktionswerkstoffen

Corrosion and Stress Corrosion Problems of Aluminium Structural Alloys. The corrosion behavior of structural Aluminium alloys in different environments is discussed. Reference is made to the important influence of naturally formed surface oxide films on corrosion resistance of Aluminium. Selected examples are given for the different types of attack, e. g. pitting corrosion, intergranular corrosion and exfoliation corrosion. The possible effect of composition and of fabricating procedures on corrosion is discussed. The stress corrosion mechanism of AlZnMg-alloys is quite different from the common corrosion process. The difficulties to distinguish between different corrosion mechanisms having apparently similar features are described. Knowledge of the different origins of failure provides possibilities for avoiding corrosion and stress corrosion damages.     

Das Verhalten von Phenolformaldehyd-Harz in trockener und feuchter Luft

Zusammenfassung Der Austrocknung wie auch der Feuchtigkeitsaufnahme bei Phenolformaldehyd-Harz überlagert sich eine Abgabe von Phenol und Formaldehyd. Dieser Vorgang l?uft au?erordentlich langsam ab. Bei Scheiben von nur 2 mm Dicke tritt der Beharrungszustand erst nach weil über einem Jahr ein. Der Stoffaustausch folgt den Diffusionsgesetzen, so da? man die Diffusionskonstante bestimmen kann. Durch H?rten des Harzes wird einerseits die Diffusionskonstante erniedrigt, andererseits infolge des beim H?rten entstehenden Kondensationswassers der Feuchtegehalt wesentlich über den des Ausgangszustandes gehoben. Milteilung aus dem Staatlichen Materialprüfamt für den Maschinenbau der Technischen Hochschule München VDI