Steam Oxidation of Creep-Strength Enhanced 9Cr Ferritic Steel: Void Formation in Oxide Scale and Its Relation to Scale Exfoliation

2004 ◽  
Author(s):  
Yutaka Watanabe ◽  
Hiroaki Kikkawa
Keyword(s):  
Ferritic Steel ◽  
Superheated Steam ◽  
Void Formation ◽  
Tensile Tests ◽  
Steam Oxidation ◽  
Oxide Scales ◽  
Void Distribution ◽  
Boiler Tubes ◽  
Fossil Power Plant

The purposes of this research are (1) evaluating the importance of voids existing in oxide scales to exfoliation of oxide scales formed in superheated steam, (2) discussing possible role of Cr-rich layer in void formation in the oxide scales. First, superheater tubes, which are made of 9Cr-1MoVNb ferritic steel and were experienced with scale exfoliation, were removed from a fossil power plant and oxidation interfaces of the boiler tubes were examined in terms of structure, void distribution, elemental profile of the oxide scales and exfoliation characteristics. Then, exfoliation behaviors of oxide scales were evaluated on actual superheater tubes and on the steam oxidation specimens experimentally oxidized in autoclaves by tensile tests in terms of exfoliation strength and of position of exfoliation and its relation with void distribution in the scales. The results indicated an important role of void formation and growth in exfoliation of scale exfoliation. Void formation mechanism was also discussed based on the observed characteristics of the oxide scales.

The Role of Alloy Composition on the Steam Oxidation Resistance of 9-12%Cr Steels

2006 ◽  
Vol 522-523 ◽  
pp. 129-138 ◽  
Author(s):  
Stephen Osgerby ◽  
A. Tony Fry
Keyword(s):  
Oxide Layer ◽  
Defect Structure ◽  
Alloy Composition ◽  
Steam Oxidation ◽  
Oxide Scales ◽  
Martensitic Steels ◽  
Minor Elements ◽  
Composition Modification ◽  
Gas Penetration

Three commercial martensitic steels have been oxidised in steam at 600 and 650 °C for times up to 10000 h. The partition of minor elements within the oxide scales has been determined. Silicon forms an additional oxide layer beneath the spinel. Chromium, molybdenum and tungsten concentrate in the spinel and manganese is present in both the spinel and magnetite. Several proposed mechanisms for steam oxidation have been examined to explain the observed effects of alloy composition. Modification of the oxide defect structure and oxidant gas penetration through microcracks were identified as the mechanisms most able to explain the influence of alloy composition.

Heat Treatments Effect on the Mechanical Properties of Industrial Drawn Copper Wires

2013 ◽  
Vol 811 ◽  
pp. 9-13 ◽  
Author(s):  
Zakaria Boumerzoug ◽  
Zakaria Boumerzoug ◽  
Vincent Ji
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Treatment Time ◽  
Void Formation ◽  
Tensile Tests ◽  
Heat Treatments ◽  
Ambient Atmosphere ◽  
Creep Tests ◽  
Prior Heat Treatment ◽  
Industrial Material

In this present investigation, the mechanical properties of industrial drawn copper wires have been studied by creep tests, tensile tests and hardness Vickers. The effect of prior heat treatments at 500°C for different time on the drawn wires behavior was the main goal of this investigation. We have found that these heat treatments influenced the creep behavior of drawn wires and recorded shape curves. The creep tests were applied under ambient atmosphere at 240 °C. The creep duration before rupture decreased with the prior heat treatment time. The creep tests results were confirmed by tensile tests. A relationship between the hardness and the ultimate tensile strength of this industrial material has been established. Optical and scanning electron microscopy observations have been also used. Cross section observations of the wire after tensile or creep-rupture tests have shown that the mechanism of rupture was mainly controlled by the void formation.

scholarly journals Suppressing Void Formation in All-Solid-State Batteries: The Role of Interfacial Adhesion on Alkali Metal Vacancy Transport

2021 ◽  
Author(s):  
Ieuan Seymour ◽  
Ainara Aguadero
Keyword(s):  
Solid State ◽  
Interfacial Adhesion ◽  
Void Formation ◽  
Rechargeable Batteries ◽  
Metal Anode ◽  
Solid State Batteries ◽  
Promising Solution ◽  
Metal Vacancy ◽  
All Solid State Batteries

All-solid-state batteries containing a solid electrolyte and a lithium (Li) or sodium (Na) metal anode are a promising solution to simultaneously increase the energy density and safety of rechargeable batteries....

Role of grain boundary engineered microstructure on high temperature steam oxidation behaviour of Ni based superalloy alloy 617

2019 ◽  
Vol 778 ◽  
pp. 224-233 ◽  
Author(s):  
C.N. Athreya ◽  
K. Deepak ◽  
Dong-Ik Kim ◽  
B. de Boer ◽  
Sumantra Mandal ◽  
...  
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Oxidation Behaviour ◽  
Steam Oxidation ◽  
Alloy 617 ◽  
High Temperature Steam

Study on Oil-Ash Corrosion and Coal-Ash Corrosion Occurred in the Flue-Gas Side of Fossil Power Plant

2011 ◽  
Vol 418-420 ◽  
pp. 918-921
Author(s):  
Yong Yan Zhou ◽  
Yu Zhou ◽  
Guo Hua Lu ◽  
Tian Sheng Chen
Keyword(s):  
Flue Gas ◽  
High Speed ◽  
Fossil Fuels ◽  
Influence Factors ◽  
Heating Surface ◽  
Coal Ash ◽  
Chemical Corrosion ◽  
Boiler Tubes ◽  
Prevention Methods ◽  
Fossil Power Plant

A large number of high-speed soot particles would be produced after fossil fuels' (oil or coal) combustion in the boiler. These high-speed particles not only directly attack the heating surface of boiler tubes (damaging the tubes mechanically), but also condensate on the wall, causing even more serious chemical corrosion. The discussion has deeply studied the occurrence sites, reaction mechanism, influence factors as well as identification and prevention methods of oil-ash corrosion, coal-ash corrosion, so it would have a positive guiding significance for reducing (or preventing) the flue-gas side corrosion.

The Role of Sulfur in the Growth and Adhesion of Oxide Scales

1989 ◽  
pp. 271-285 ◽  
Author(s):  
J. G. Smeggil ◽  
A. J. Shuskus ◽  
N. S. Bornstein ◽  
M. A. DeCrescente
Keyword(s):  
Oxide Scales
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