Corrosion prevention design

Jones, M. M. and Welker, E. E., "Electrical Component Corrosion Prevention, Designing for Automotive Corrosion Prevention, SAE P-78, Warrendale, PA, 1978. 

These fibers may find use in controUed release of dmgs, bactericides, and corrosion prevention chemicals (103). Fibers with different active groups have been made for sorption of chemicals. These fibers are designed to replace granular sorbents for air purification, for example, in air filtration masks (104). 

In the above discussion only the drillstem was discussed. However, when designing other systems in drilling operation, such as drilling fluid systems and casing design to name a few, the engineer must also consider corrosion prevention. 

Temporary corrosion preventives are products designed for the short-term protection of metal surfaces. They are easily removable, if necessary, by petroleum solvents or by other means such as wiping or alkaline stripping. Some products for use in internal machine parts are miscible and compatible with the eventual service lubricant, and do not, therefore, need to be removed. 

Corrosion and corrosion prevention are also the subject of one of the design guides published by the Design Council, Ross (1977). 

Probably the most important feature of the "wet" methanol hydrocarbon flash results in the enhanced carbon dioxide solubility in the liquid water phase. This would probably mean potentially more severe corrosion problems in the pipeline and associated equipment. The design and operation of the corrosion prevention system and program can be substantially improved. 

Corrosion. Anticorrosion measures have become standard in pipeline design, construction, and maintenance in the oil and gas industries the principal measures are application of corrosion-preventive coatings and cathodic protection for exterior protection and chemical additives for interior protection. Pipe for pipelines may be bought with a variety of coatings, such as tar, fiber glass, felt and heavy paper, epoxy, polyethylene, etc, either pre-applied or coated and wrapped on the job with special machines as the pipe is lowered into the trench. An electric detector is used to determine if a coating gap (holiday) exists bare spots are coated before the pipe is laid (see Corrosion and corrosion control). 

Even without heating it is likely that in the course of each pass there will be some release of volatile material—like water vapour, plasticizer, extender, or processing aids (anti-static agent or lubricant). There must be opportunity for such substances to be vented and carried away the die or tool must be capable of resisting attack by volatiles (suitably plated if they are corrosive), and designed to prevent an accumulation of released materials. Special hardened... 

Some dichromate conversion coatings and wash primers designed for corrosion prevention are suitable for adhesive bonding. 

Corrosion prevention and protection arrests the degradation of metals/materials and contributes in a significant way to the conservation of resources with minimum damage to the ecosystems. Since materials are prone to corrosion it is useful to know the factors both direct and indirect, which affect the choice of materials and their related corrosion resistance of paramount importance in the design of an engineering structure. 

Corrosion prevention involves inherent factors, which are within the control of the metallurgist or engineer. The three main categories considered are materials selection, design factors and life prediction analysis. 

Corrosion protection refers to a situation in which all the inherent factors to prevent corrosion have been optimized and external intervention is deemed necessary to minimize the corrosion that is beyond the scope of corrosion-preventative factors such as metallurgical, design and life prediction analysis. Corrosion protection can be achieved by (i) addition of inhibitors and (ii) use of protective coatings. 

The selection of an alloy for a specific application is based on the cost and the corrosion resistance of the alloy in the environment of interest. It is also possible to subject the chosen alloy to a process by which the corrosion resistance of the selected material can be improved within the acceptable limits. Some of the corrosion prevention and protection strategies with respect to the aluminum-based alloys are (i) design (ii) alloy selection and joint sealants (iii) aluminum thermal spraying anodic coatings (iv) inhibitors (v) conversion and organic coatings and (vi) cathodic protection. 

Solid films are not generally as effective in corrosion prevention as either lubricating oils or paints, so that careful attention should be paid to corrosion-resistant materials and treatments and design features. 

Another aspect of design that can influence corrosion prevention is the design of welds. Proper sizing of the welds and planning the sequence of the welds can reduce stress concentrations and distortions of the hull. Past experience has shown that lap joints have been prone to failure on older ships therefore, butt-welded joints should be used whenever possible. Designs should also avoid intermittent spot welding as this form of welding is more prone to corrosion. 

CP or other protection systems should be incorporated, if necessary, in the design phase of the ship. CP system is a secondary defense against corrosion when holidays or cracks form in the coating. CP systems use either sacrificial zinc anodes or impressed-current systems to mitigate corrosion. Other corrosion prevention equipment and materials are inert gases to drive out corrosive gases. Corrosion inhibitors are also used. 

The Battelle-NBS study (1) used an economic input/output analysis to estimate the cost of corrosion in the United States. In the model, the US economy was divided into 130 industrial sectors. For each sector, estimates were made on the costs of corrosion prevention, as well as the cost of repair and replacement because of corrosion. The following direct costs were included in the study replacement of equipment or buildings loss of product maintenance and repair excess capacity redundant equipment corrosion control such as inhibitors organic and metallic coatings engineering research and development testing design insurance parts and equipment inventory. 

W.R. Peterson, Designing for automotive corrosion prevention, in Proceedings of the Society of Automotive Engineers, Troy, MI, 1978, pp. 78-88. 

Figure 7.47 Prevention of erosion corrosion by design. (Partly reproduced from Pludek [7.3] with permission of Palgrave MacMillan.)...

The choice between these possibilities is usually based upon economic considerations, but in many cases aspects such as appearance, environment and safety must also be taken care of Two or more of the five principles are commonly used at the same time. It is important to decide upon corrosion prevention at the design stage. In addition to the sections in the present chapter, reference is made to recommended protection methods under the treatment of various corrosion forms in Chapter 7. 

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