Investigations into the Influence of Notches on Creep Strength at High Temperatures

2009 ◽  
pp. 93-93-38
Author(s):  
W. Siegfried
Keyword(s):  
High Temperatures ◽  
Creep Strength

Creep Behaviour of a Thermoresistant Steel Working under Thermal Loads

2014 ◽  
Vol 601 ◽  
pp. 100-103
Author(s):  
Mihai Hluscu ◽  
Pavel Tripa
Keyword(s):  
High Temperatures ◽  
Creep Strength ◽  
Creep Behaviour ◽  
Thermal Loads ◽  
Creep Tests ◽  
Actual Problem ◽  
Methane Gas ◽  
Strength Variation

The estimation of the lifetime for equipments and installations working at high temperatures represent an actual problem. In the last years, there have been proposed a lot of methods in order to evaluate the lifetime for the equipments working under creep conditions. In the frameworks of the paper, some results regarding the behavior of pipes belonging to a methane gas cracking reactor are presented. Pipes worked on about 160.000 hours under a pressure of 14 at and a temperature of 800°C. The behavior of the pipes under above mentioned pressure has been calculated and plotted. Creep tests were performed at 650 and 800°C, and on these bases was evaluated the creep strength of the material. With Larson-Miller method the results were prolonged for spans shorter than 10.000 hours. The creep strength variation curves, drawn for 1000 and 100000 hours can be used for predictions about the lifetime at different.

SANDVIK 8R30, 8R30H

Alloy Digest ◽  
1995 ◽  
Vol 44 (11) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Mechanical Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Temperatures ◽  
Creep Strength ◽  
Heat Treating ◽  
Nickel Steel ◽  
Stainless Chromium

Abstract Sandvik 8R30 is an austenitic, titanium-stabilized stainless chromium-nickel steel. It is suitable for wet-corrosive service, but also has good mechanical strength at high temperatures. For applications requiring enhanced creep strength, it is recommended that the variant Sandvik 8R30H be used. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-622. Producer or source: Sandvik.

The Properties and Mode of Rupture of a Molybdenum and a Molybdenum-Vanadium Steel, Judged from Prolonged Creep Tests to Fracture

1941 ◽  
Vol 146 (1) ◽  
pp. 208-222 ◽  
Author(s):  
H. J. Tapsell ◽  
C. A. Bristow ◽  
C. H. M. Jenkins
Keyword(s):  
High Temperatures ◽  
Creep Strength ◽  
Carbon Steels ◽  
Creep Tests ◽  
Alloy Steels

The accompanying report deals with the nature of the failure at high temperatures of certain alloy steels, which are being used to replace carbon steels, and indicates the conditions of use under which the development of intercrystalline cracking can be avoided. Investigations are being continued with a view to finding steels of high creep strength, in which the onset of intercrystalline cracking can be displaced to higher temperatures.

In situ REM imaging of surface processes on ceramic bulk crystals from 300 to 1670 K in a conventional TEM

1991 ◽  
Vol 49 ◽  
pp. 660-661
Author(s):  
Z. L. Wang ◽  
J. Bentley
Keyword(s):  
High Temperatures ◽  
Image Resolution ◽  
Atomic Processes ◽  
Crystal Surfaces ◽  
Beam Radiation ◽  
Surface Areas ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Gas Reactions

Studying the behavior of surfaces at high temperatures is of great importance for understanding the properties of ceramics and associated surface-gas reactions. Atomic processes occurring on bulk crystal surfaces at high temperatures can be recorded by reflection electron microscopy (REM) in a conventional transmission electron microscope (TEM) with relatively high resolution, because REM is especially sensitive to atomic-height steps.Improved REM image resolution with a FEG: Cleaved surfaces of a-alumina (012) exhibit atomic flatness with steps of height about 5 Å, determined by reference to a screw (or near screw) dislocation with a presumed Burgers vector of b = (1/3)<012> (see Fig. 1). Steps of heights less than about 0.8 Å can be clearly resolved only with a field emission gun (FEG) (Fig. 2). The small steps are formed by the surface oscillating between the closely packed O and Al stacking layers. The bands of dark contrast (Fig. 2b) are the result of beam radiation damage to surface areas initially terminated with O ions.

High Temperature n- and p-type Doped Microcrystalline Silicon Layers Grown by VHF PECVD Layer-by-Layer Deposition

2003 ◽  
Vol 762 ◽  
Author(s):  
A. Gordijn ◽  
J.K. Rath ◽  
R.E.I. Schropp
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
High Temperatures ◽  
Continuous Wave ◽  
Hydrogen Plasma ◽  
Silicon Layer ◽  
Dark Conductivity ◽  
High Deposition Rate ◽  
Layer By Layer ◽  
Microcrystalline Silicon

AbstractDue to the high temperatures used for high deposition rate microcrystalline (μc-Si:H) and polycrystalline silicon, there is a need for compact and temperature-stable doped layers. In this study we report on films grown by the layer-by-layer method (LbL) using VHF PECVD. Growth of an amorphous silicon layer is alternated by a hydrogen plasma treatment. In LbL, the surface reactions are separated time-wise from the nucleation in the bulk. We observed that it is possible to incorporate dopant atoms in the layer, without disturbing the nucleation. Even at high substrate temperatures (up to 400°C) doped layers can be made microcrystalline. At these temperatures, in the continuous wave case, crystallinity is hindered, which is generally attributed to the out-diffusion of hydrogen from the surface and the presence of impurities (dopants).We observe that the parameter window for the treatment time for p-layers is smaller compared to n-layers. Moreover we observe that for high temperatures, the nucleation of p-layers is more adversely affected than for n-layers. Thin, doped layers have been structurally, optically and electrically characterized. The best n-layer made at 400°C, with a thickness of only 31 nm, had an activation energy of 0.056 eV and a dark conductivity of 2.7 S/cm, while the best p-layer made at 350°C, with a thickness of 29 nm, had an activation energy of 0.11 V and a dark conductivity of 0.1 S/cm. The suitability of these high temperature n-layers has been demonstrated in an n-i-p microcrystalline silicon solar cell with an unoptimized μc-Si:H i-layer deposited at 250°C and without buffer. The Voc of the cell is 0.48 V and the fill factor is 70 %.

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