THE CHEMICAL WORLD THIS WEEK C&EN REPORTS: National Association of Corrosion Engineers, South C e n t r a l Region
Plastics for Corrosion Resistance Continue to Be Emphasized Production of plastics chemical e q u i p m e n t w i l l increase
anilines, and alkylated pyridines. T h e studies were carried out on both steel coupons and iron p c w d e r in solutions of 1 Ν hydrochloric acid, with t h e results on both powder a n d coupons agreeing closely. Heat Treatment v s . Corrosion Resist ance. Straight chromium hardenable stainless steels have found - steadily in creasing use in the last 10 years because of resistance to certain types of corrosion plus ability to be heat-treated for a wide range of hardness or strength. T h e least costly of the stainless steel alloys, over one million pounds w e r e used b y the petroleum industry in 1951. Recent fail ures, according to F . K. Bloom, Armco Steel Corp., indicate that heat treatment of alloy steels may h a v e a decided effect on their corrosion resistance. Mr. Bloom stressed the importance of specifying intended application . a n d fabricating methods and heat treatments to b e e m ployed when ordering these materials. As an example h e mentioned that t h e m e chanical properties of t h e lower carbon alloys, such as types 4 0 3 , 410, 414, 416, and 4 3 1 , are necessarily dependent on composition a n d that when these grades are to b e heat-treated within a narrow range of mechanical properties, this should be borne in mind. In general, he said that corrosion rate on these alloys increases to a maximum between 800° F . and 1100° F., reheating temperature, a n d then falls off. Toughness increases slowly to a maxi m u m at about 1500° F., then falling off sharply, and hardness decreases sharply in t h e range 1000° t o 1500° F., followed by a sharp increase.
ance. Binders of carbon, acid-leached N E W ORLEANS.-Applications of plas tics in t h e chemical processing field today asbestos, blue African asbestos, and sili are still primarily as protective coatings, con oxides, however, will provide maxir linings, cements, joint materials, and cast mum corrosion resistance. structures. As additional technical infor Iron and Steel Corrosion. Bacterial mation becomes available, R. B. Seymour corrosion of steel structures used in* off told corrosion engineers, the use of reac shore drilling has b e e n studied on a labo tion vessels, towers, hoods, and pipe cast ratory scale by t h e H u m b l e Oil and· R e from filled plastics is expected to increase. fining Co. Maximum rates of corrosion Dr. Seymour, of Atlas Mineral Products of steel coupons u n d e r anaerobic condi Co., outlined some of the newer advances tions, b y sulfate-reducing bacteria in both in coatings and cements before the south natural muds and synthetic media, were of central meeting of the National Associa the order of 0.001 i n c h per year. T h e con tion of Corrosion Engineers in New Or clusion of J. A. Caldwell is that although leans, Oct. 1 to 3. bacterial corrosion of iron in environments Vinyl-vinylidene chloride type plastics in which offshore structures are located is have been recently selected as one of the a possibility, t h e corrosion rate is so low better gasoline and salt water-resistant that cathodic protection provides a suf coatings, Dr. Seymour said, and tests with ficient safeguard. a highly filled aluminum vinyl paste have Amine Inhibition. Evaluation studies on shown considerable promise in coating various aliphatic a n d aromatic amines as vegetable and mineral oil storage tanks. corrosion inhibitors, made b y C. C. Liquid neoprene, which he considers to Nathan, The Texas Co., indicate that in come closer to meeting requirements of general the efficiency of inhibition in an ideal coating than any other material, creases with molecular weight in a h o has been recently improved to make it mologous series. D r . Nathan confirmed hydrochloric acid resistant and applicable this with data for alkyl amines, substituted in thicknesses as great as 20 mils per coat. Recent developments in chemically re sistant cements which he reported are C & E N REPORTS: A m e r i c a n Coke and C o a l Chemicals Institute two which will actually adhere to both Portland cement and steel. O n e of these is a modified phenolic cement curing under alkaline conditions. The other, one of the few cements resistant to chlorine dioxide, cures under neutral conditions. Plastics Do's and Don'ts. Many factors must b e considered in order to obtain Benzene f r o m p e t r o l e u m c a n n o t c o m p e t e in price good performance of plastics in corrosion resistance. "Avoid thin films, except in with that f r o m coal t a r , but v o l u m e is increasing mildly corrosive environments or in com W H I T E S U L P H U R SPRINGS, W . V A . ing. In this, h e said, they were right from bination with inhibitors and cathodic pro Programs for increased production facili a scientific standpoint b u t not from an tection," warned F . L. Whitney, Jr., Mon ties in benzene a n d phthalic anhydride economic one. santo. When such a film is used, he said may still fall short of our requirements " W e could not produce benzene to further, it should never b e applied over owing to new d e m a n d s for these basic compete in a 17-cent market ( t h e market a base metal which in itself has no cor chemicals in civilian and military prod at that time for coke-oven b e n z e n e ) , or rosion resistance to the environment. ucts, it was declared before t h e recent even come close to it." But many oil re Other points to remember, as enumer meeting of the American Coke and Coal finers were prepared for t h e develop ated b y Mr. Whitney, are ( 1 ) modifica Chemicals Institute. The benzene supply ment through such unrelated circumstances tion of plasticization of a pure product from coal will be only 0 0 % of what will as rising demands for higher octane gaso completely polymerized generally lowers b e needed, and w h i l e phthalic anhydride line and their research which sought more corrosion resistance, although mechanical production has reached the heighth of 250 tailor-made branch aliphatic and aromatic improvement resulting may oflVt this; million pounds a year, the limit for its materials from petroleum streams. ( 2 ) polymerization effected by heat or uses does not a p p e a r to b e in sight, said Last year, Mr. Tracy continued, 28 catalysis may be expected to produce m a Osgood V. Tracy, chemical products man million gallons of b e n z e n e were produced terials having good corrosion resistance ager for Esso Standard Oil. from petroleum. In 1952 the volume may for t h e environment in which they a r e Benzene Demand. T h e speaker re reach 4 5 million gallons, and on the basis applicable, but generally brittle and hav viewed the growth of benzene demand in of projects approved, t h e output in 1955 ing other limiting physical properties; ( 3 ) recent years and t h e emergencies past and is estimated at about 145 million gallons. pigmentation and the use of binders, par present which b r o u g h t the petroleum in This will supplement the 235 million gal ticularly in molded or cast plastics, gen dustry into t h e picture as a producer of lons which must b e either produced by erally result in reduced corrosion resist- toluene and b e n z e n e through Ilydroformcoke ovens and tar distillers, or imported
Coal Chemical Needs Rising, Naphthalene Sources Sought
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