UK national Centre for Advanced Tribology launched

Abstract

The national Centre for Advanced Tribology at Southampton (nCATS) is a new £10m initiative, partly funded by the UK Engineering and Physical Sciences Research Council (EPSRC), that will prepare the next generation of engineers to underpin future technological advances in microsystems, biomedical engineering and engineering.     

16th IFHTSE Congress

Abstract

The 16th Congress of the International Federation for Heat Treatment and Surface Engineering (IFHTSE) will take place on 30 October to 2 November 2007 in Brisbane, Australia. Its mission is to provide a global showcase for developments in technology and research in the key activities of thermal processing and surface engineering, as applied to elaborately transformed manufactured products.     

University of Malta to offer European master's degree in heat treatment and surface engineering

Abstract

Following research into needs, a E560 000 project – MinSE, largely funded by the EU under the Socrates programme – has been launched to design and test a course leading to a European master's qualification in heat treatment and surface engineering. The part online, part face-to-face course will be offered initially by the University of Malta starting 2009.     

Stress Corrosion Test Methods

Abstract

In the hope that some of the pitfalls may in future be avoided, the paper discusses problems associated with the various methods of stress corrosion testing, without providing a catalogue of test methods. Thus, the use of time to failure as a parameter that measures susceptibility may lead to erroneous conclusions, whilst designers may be misled if they are not aware that K_ISCC values, as sometimes determined from pre-cracked specimen tests, are not as reproducible as those design parameters, such as yield stress or ultimate tensile stress, with which they are more familiar. The effects of specimen surface area, and its relation to solution volume, as well as surface finish, are among other quantities that may cause discrepancies between results from different laboratories. Similarly, in relation to environmental aspects of testing, the dangers in the use of ‘standard’ solutions are indicated and the necessity, in simulating service failures, of precisely reproducing the composition of the environment and the relevant electrode potential are shown, as well as the importance of other factors.     

Publications

Abstract

Personal views are expressed on the information aids most required to convey information on corrosion to engineers. What is now done is less than adequate and there is an urgent need for progress. The objective of the paper is to stimulate debate on the subject, as a first step, since at present there is no agreement on what is required.     

Corrosion of Mild Steel by Iron Sulphides

Abstract

The corrosiveness of several chemically prepared iron sulphides to mild steel has been studied with regard to the amount of sulphide and the period of exposure of the steel to the sulphide. All sulphides examined were found to be corrosive and there appears to be a link between corrosiveness and the sulphur content of the sulphides. The corrosion mechanism is discussed in the light of the literature.     

Amines as Corrosion Inhibitors for Aluminium-Manganese Alloy in Phosphoric Acid

Abstract

The corrosion of 3S aluminium (Al-Mn alloy) and its inhibition in solutions of phosphoric acid has been studied. The extent of corrosion increases with increase in acid concentration and with the length of the period of immersion. At 0·5% inhibitor concentration the efficiency of the inhibitors increases in the order: triethylamine < dicyclohexylamine < diethylamine < di-n-propylamine < cyclohexylamine < n-butylamine < ethylamine < trimethylamine < ethylenediamine < hexamine < isopropylamine < dimethylamine < methylamine < n-propylamine. At constant acid concentration the inhibitor efficiency increases with increase in the concentration of the inhibitor, whereas at constant inhibitor concentration the efficiency decreases with increase in the concentration of the acid. Very little correlation appears to exist between the pK_b values or the molecular weight of the inhibitor and the extent of inhibition. Maximum inhibition is achieved in those cases where the pH of the inhibited solution lies in the range 4·5 to 8·5, but where the solution is required for use at low pH values, then hexamine appears to be the most suitable inhibitor.     

About the Authors

Abstract

Anisotropy in stress corrosion cracking of lean grade UNS S32101 and standard grade UNS S32205 hot rolled duplex stainless steels was evaluated in this study. Microstructures were characterised with stereology methods in three orthogonal orientations to quantify anisotropy in phase distribution. Constant extension rate tests were conducted in an autoclave at 2×10^?6 s^?1 in chloride containing alkaline sulphide solution at 170°C. The maximum crack lengths and average crack densities were measured for the rolling longitudinal and transverse longitudinal orientations after stress corrosion cracking tests. Results indicate that stress corrosion crack initiation and growth are a strong function of the microstructure in each orientation. Maximum crack length and average crack density were maximum for the rolling longitudinal orientation. Crack initiation and growth were favoured along the transverse direction. Chlorides enhanced anisotropy in crack growth behaviour by facilitating crack initiation and crack coalescence along phase boundaries, which lead to more severe stress corrosion cracking in the alkaline sulphide environments that were studied.     

Corrosion Protection of Steel Highway Bridges: I Full scale trials of paint systems

Abstract

Full scale trials of ten paint systems, applied on the plate girders of the Loudwater Viaduct, are described. The best performance during four years of exposure was given by a solvent less epoxy system, but its application requirements were stringent and may be difficult to meet in practice. For high corrosivity sites, a chlorinated rubber paint system should give a good performance with easy application, although transportation damage between fabrication shop and site may be a problem. A general conclusion is that aluminium pigment should be excluded from conventional micaceous iron oxide paints. In several instances aluminium has been leached out as aluminium salts leading to deterioration. of the paint system and rusting of the substrate.

The importance of the micro-climate to which sheltered bridge steelwork is exposed is discussed. Steel girders are not washed by rain and the combination of corrosive contaminants and long periods of wetness can be a particularly severe condition for paint coatings under a bridge deck. Further research on the characterisation of bridge sites and evaluation of priming paints has been initiated.     

Nature of the Oxide Film Present on Iron after Inhibition in 0·05 M Chromate Solutions

Abstract

Chemical and microprobe analyses have been used to study the composition of the oxide films formed on iron by 0·05 M potassium chromate, pH 4–8.

Chemical analyses have shown that the air-formed oxide film was thinned and evenly reinforced with a normal iron chromium spinel having a composition in the range Fe²⁺ (Fe³⁺_0·5 Cr³⁺_1·5)O₄ — Fe³⁺ Cr³⁺ O₃

Microprobe analyses indicated enrichment of chromium at scratch lines, but the effect was small compared with the overall thickening of the films.