ETHODS of corrosion prevention ally attacked if assembled with zinc, used in the United States for galvanised or cadmium-plated steel, cad aluminium alloy windows and doors are mium-plated copper alloys or stainless steel. summarised in a report issued by the Office Corrosion is a very complex pheno of Technical Services, Washington. An menon, however, and it is difficult to lay notated references are given to information down any hard and fast standards on this on the corrosion behaviour of aluminium subject. The alloys mentioned are those windows and doors in marine, industrial whose stability was rated most highly, but and rural atmospheres, and to suitable under many conditions others have also methods of treatment. Data on alloy com been successfully used. positions and the utilisation of standard Anodising or other treatments are not sections are also included. in general use on aluminium for window frames because of the cost involved. It is Th e alloys most commonly used in the United States for general structural applica important that the sections forming a struc tions are 61S and 14S. The yield strength ture should be strong enough and thick of 61S-T6 is about the same as that of enough to withstand distortion when structural steel, a minimum of 35,000 p.s.i., handled and stacked. The joints should although the minimum ultimate tensile be welded and the flux carefully removed. Contact with copper, lead and other strength is only 42,000 p.s.i. The alloy has a resistance to corrosion about equal electro-positive metals in rivets, bolts, etc., to that of pure aluminium. It is easily should be avoided, since this will cause fabricated into the forms that are required severe local corrosion of the aluminium and hence has the advantage of lower cost and early failure in service. than some other alloys. An acrylate liquor is useful for protect The effects of marine, industrial and ing the aluminium from corrosion by lime water or mortar solutions until the frame rural atmospheres on several aluminium- is bricked in. Natural weathering pro sheet materials have been compared. duces a hard, corrosion-resistant protective Generally speaking, after 10-year tests, rural environments were found to be only surface on aluminium in windows for most slightly corrosive. In these tests, which service conditions. Anodising is used were sponsored by the American Society mainly on architectural panels, where a dull surface appearance is required. for Testing Materials, long-term exposure to industrial and marine atmospheres did If it is desired to modify the appearance not produce significant corrosion of the of aluminium by painting for specific aluminium alloys tested. design effects, phosphating or chromatis- A manual issued by the Reynolds Metals ing treatments have been found useful in improving the adherence of paint, accord Co. Inc., Louisville, Kentucky, states that ing to research carried out at the U.S. all commercial wrought aluminium alloys Bureau of Standards for the Housing and are suitable for rural atmospheres. Those Home Finance Agency. recommended for industrial and marine atmospheres respectively are separately For good corrosion resistance the copper listed. Particulars are also given of the content of the aluminium should be kept aluminium alloys most commonly used for low; preferably under 0.4%. extrusions, which contain varying com The U.S. Navy suggests that bright binations of such elements as silicon, mag aluminium surfaces should be either waxed nesium, copper, chromium, manganese or coated with phenolic varnish, formula and zinc. They are available in various 80. This includes aluminium bins, up tempers—solution heat-treated, and arti rights, battens and fittings in store or issue ficially aged. Aluminium extrusion alloys rooms, lockers, mess tables, shelves, dres containing magnesium, or magnesium and sers and drawers. The surfaces of material silicon rather than copper, and which are most readily accessible for inspection and solution treated rather than heat treated, maintenance should be given two coats of are the most resistant to corrosion attack zinc chromate primer; most other surfaces by salt water and marine atmospheres. require one coat of primer. Where corrosion has occurred in struc Where it is necessary to remove surface tures exposed to the atmosphere, the failure contamination or old paint from aluminium cannot be assumed to be solely the result surfaces, mixed spirits, solvent-type paint remover, wire brushing or sandblasting of weathering. Aluminium is quite sus are recommended. ceptible to galvanic corrosion. Thus aluminium will usually corrode in assemb The decision as to whether aluminium lies with steel, brass, copper, lead, tin or structures should be painted or left exposed nickel, when contaminated water pene depends largely on the corrosive effect of the trates into the joint. Galvanic attack is local atmosphere conditions. For this reason most effectively eliminated by using only it is usually advisable to consult an expert. aluminium parts. Where this is impossible, A copy of this report has been received the contacting surface should be insulated by the Technical Information and Docu with zinc chromate, or bituminous paints, ments Unit of the Department of Scientific or by gaskets of a corrosion-resistant, non- and Industrial Research, 15 Regent Street, galvanic material. Aluminium is not gener London, S.W.1 (ref.: TIDU 0897/58). CORROSION TECHNOLOGY, December 1954 389
Anti-Corrosion Methods and Materials – Emerald Publishing
Published: Oct 1, 1954
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera