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Exposure to Marine Atmosphere

This is the case of ships and equipment at the seaside. The metal is exposed to marine winds that are more or less loaded with salt, to high marine humidity, and possibly to mould that may develop on the metal. The corrosion resistance under these conditions has been discussed in Part C. [Pg.341]


Conditions of exposure to marine atmosphere, even if not in direct contact with seawater, are aggressive. [Pg.167]

Marine Coatings n Paints and varnishes specifically formulated to withstand water immersion and exposure to marine atmosphere. See also Spar Varnish. [Pg.445]

On a launch vehicle, high strength 17-4 PH steel bolts were used on an aluminum body oxidizer valve. This martensite steel was heat treated (H-900 condition) to a minimum strength of 190000psi. On exposure to marine atmosphere at Cape Kennedy, the bolts were found to be cracking. [Pg.220]

For special purposes, more complex equipment is occasionally used (not covered by 4665) which additionally attempts to simulate corrosive or polluted atmospheres. There is an ISO standard for plastics for a salt spray exposure test93 which could in principle be applied to rubber should such an exposure be needed. Cyclic exposure to corrosive atmosphere could be more representative of service94,95. One particular circumstance is exposure to a marine environment and there is an ISO standard covering this for plastics96. [Pg.342]

Atmospheric exposure of materials such as Type 410 steel to marine atmosphere resulted in an average penetration rate of 0.20 pm/yr and 0.125 mm deep pits at the end of... [Pg.224]

In order to fully appreciate the reasons for carrying out the conservation method selected, it is important to understand in the first instance how the metal or alloy was manufactured. From modern theories of corrosion of metals in marine environments, it is possible to predict the mode of corrosive attack that the artefact may have experienced while being buried or laying on the bottom of the ocean floor. Any adverse effect on the rate of corrosion on exposure to the atmosphere can possibly be predicted. From this knowledge, the most efficient methods of field treatments, storage conditions and conservation can be recommended. [Pg.123]

Atmospheric exposure. Excellent resistance to rural, urban, and industrial atmospheres lesser resistance to marine atmospheres. [Pg.391]

Exfoliation is commonly experienced on exposure of susceptible aluminum alloys to marine atmospheres. Simulation in the laboratory is accomplished by controlled intermittent spray with 5% NaCl containing added acetic acid to pH 3 at 35-50°C (95-120°F) [28]. In practice, severe exfoliation corrosion has been experienced in water irrigation piping constructed of type 6061 alloy [29]. The cause in this instance was ascribed to pipe fabrication methods and presence of excess amounts of impurity elements (e.g., Fe, Cu, and Mn). [Pg.394]

By alloying nickel with both molybdenum and chromium, an alloy is obtained resistant to oxidizing media imparted by alloyed chromium, as well as to reducing media imparted by molybdenum. One such alloy, which also contains a few percent iron and tungsten (AUoy C), is immune to pitting and crevice corrosion in seawater (10-year exposure) and does not tarnish appreciably when exposed to marine atmospheres. Alloys of this kind, however, despite improved resistance to Cl, corrode more rapidly in hydrochloric acid than do the nickel-molybdenum alloys that do not contain chromium. [Pg.412]

Seawater Titanium resists corrosion by seawater up to temperatures as high as 260°C. Titanium tubing, exposed for 16 years to polluted seawater in a surface condenser, was slightly discolored but showed no evidence of corrosion. T itanium has provided over 30 years of trouble-free seawater service for the chemical, oil-refining, and desalination industries. Exposure of titanium for many years to depths of over a mile below the ocean surface has not produced any measurable corrosion. Pitting and crevice corrosion are totally absent, even if marine deposits form. The presence of sulfides in seawater does not affect the resistance of titanium to corrosion. Exposure of titanium to marine atmospheres or splash or tide zone does not cause corrosion. [Pg.317]

The deterioration of concrete depends on the exposure conditions. Concrete not immersed but exposed to marine atmosphere will be subj ected to corrosion of reinforcement and frost action. Concrete in the tidal zone, however, will be exposed to the additional problems of chemical decomposition of hydrated products, mechanical erosion, and wetting and drying. Parts of the structure permanently immersed are less vulnerable to frost action and corrosion of the reinforcing steel. [Pg.66]

The pitting depth on aluminium-silicon alloys does not exceed 200 p,m after 10 years of exposure to marine or industrial atmospheres [11,12]. The stress corrosion resistance of 42000 (A-S7G) alloys is excellent [13]. [Pg.220]

The relative susceptibHity of several commercial aHoys is presented in Table 8. The index used is a relative rating based on integrating performance in various environments. These environments include the harsh condition of exposure to moist ammonia, Hght-to-moderate industrial atmospheres, marine atmosphere, and an accelerated test in Mattsson s solution. The latter testing is described in ASTM G30 and G37 (35,36) and is intended to simulate industrial atmospheres. The index is linear. A rating of 1000 relates to the most susceptible and zero designates immunity to stress corrosion. [Pg.226]

The reproducibility of test results between labs using the neutral salt spray tests has not been consistent, but the repeatability, within one lab, is better, and the test has value in comparing variations in coating systems. Correlation of hours of exposure in the salt spray test to actual performance of the plated part in service, even in marine atmospheres, is not consistent and usually avoided. A classic example is that cadmium deposits outlast zinc deposits on steel in salt spray tests and clean marine atmospheres, yet zinc outlasts cadmium when exposed to real, industrial atmospheres, because of the presence of sulfur-bearing corrodents in industrial environments. An important variable in salt spray testing is the position of the surface to be tested. Whereas the surface of test panels is specified to be 15—30° from the vertical (40), when salt spray testing chromated zinc-plated specimens, this range has appeared excessive (41). [Pg.151]

In the tests described by Tracy, a high-tensile brass suffered severe dezinc-ification (Table 4.11). The loss in tensile strength for this material was 100% and for a non-arsenical 70/30 brass 54% no other material lost more than 23% during 20 years exposure. In Mattsson and Holm s tests the highest corrosion rates were shown by some of the brasses. Dezincification caused losses of tensile strength of up to 32% for a P brass and up to 12% for some of the a-P brasses no other materials lost more than 5% in 7 years. Dezinc-ification, but to a lesser degree, occurred also in the a brasses tested, even in a material with as high a copper content as 92%. Incorporation of arsenic in the a brasses consistently prevented dezincification only in marine atmospheres. [Pg.690]

Tests by Clark for the Corrosion Sub-committee of the American Welding Society were carried out at severe marine and industrial sites. After four years, the greatest protection to steel was given by sprayed aluminium coatings combined with aluminium vinyl paint in the following environments id) sea air, ib) sea-water immersion, (c) alternate sea-water immersion and exposure to air (tidal conditions) and id) industrial atmospheres contaminated with sulphur compounds. [Pg.472]

In conclusion, relative cost and relative behaviour towards different conditions of exposure lead to the use of zinc on parts on which thick films can be tolerated and for general industrial use, and of cadmium for fine-tolerance special applications, such as aircraft and instrument parts, required to withstand conditions include humid and marine atmospheres. [Pg.483]

Conditions within a few hundred metres of the surf line on beaches are intermediate between total immersion in sea-water and normal exposure to a marine atmosphere. High corrosion rates can occur on some tropical surf beaches where the metal remains wet and where inhibiting magnesium salts are not present in the sea-water. [Pg.493]

The hardness of such coatings may reach a maximum of about 400 Hy as compared with approximately 50 Hy for a soft gold deposit. A series of corrosion studies in industrial and marine atmospheres by Baker" has indicated that the protective value of hard gold coatings is comparable with that of the pure metal, and that a thickness of only 0-002 5 mm gives good protection to copper base alloys during exposure for six months. [Pg.560]

S mm and which, as indicated earlier, places strict limitations on the usefulness of the coating for protection against severely corrosive liquid environments. The value of rhodium in resisting atmospheric corrosion in environments ranging from domestic to marine and tropical exposure has, however, been amply demonstrated by experience, and it appears probable that further developments in technology may lead to still wider application. [Pg.561]

Paint for structural steelwork is required mainly to prevent corrosion in the presence of moisture. In an industrial atmosphere this moisture may carry acids and in a marine atmosphere this moisture may carry chlorides. Paint is therefore required to prevent contact between steel and corrosive electrolytes, and to stifle corrosion, should it arise as a result of mechanical damage or breakdown of the coating through age and exposure. [Pg.637]

There are clear connections between food habits and the levels of different POPs, including PCCD/PCDFs and coplanar PCBs, found in humans. The current substances, especially PCBs, have been shown to be capable of transport over long distances. Indigenous people who rely heavily on marine mammals will therefore face a comparably high exposure to different POPs, and atmospheric transport is likely to play an important role in the presence of these animals in remote areas. [Pg.407]

Atmospheric corrosion of lead involves exposure to industrial, rural and marine environments. The mode of corrosion in the three environments is different. The rural environment consists of humidity, airflow and rainfall, which may be considered to be innocuous. The marine environment consists of chloride entrained in air and could... [Pg.267]


See other pages where Exposure to Marine Atmosphere is mentioned: [Pg.689]    [Pg.333]    [Pg.341]    [Pg.689]    [Pg.333]    [Pg.341]    [Pg.195]    [Pg.902]    [Pg.450]    [Pg.561]    [Pg.969]    [Pg.260]    [Pg.479]    [Pg.590]    [Pg.998]    [Pg.556]    [Pg.137]    [Pg.138]    [Pg.138]    [Pg.728]    [Pg.438]    [Pg.478]    [Pg.483]    [Pg.502]    [Pg.828]    [Pg.36]    [Pg.435]    [Pg.1075]    [Pg.595]   


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