Coatings for carbon steel

The best generic coatings for carbon steel that may be surrounded by wet insulation in the 140° to 250° F (60° to 120° C) range are the epoxy phenolic and the amine-cured coal tar epoxy formulations. 

NACE Publication 6H189, A State-of-the-Art Report of Protective Coatings for Carbon Steel and Autenitic Stainless Steel Surfaces under Thermal and Cementitious Fire Proofing — A Technical Report by the National Association of Corrosion Engineers Task Groups 7-H-31, 1989. 

Air Product and Chemicals, Inc. (USA) have found out that (in the absence of any topcoat) while the doped electrically conductive form of PAni performed well as a corrosion-resistant coating for carbon steel, the undoped, nonconductive form of PAni performed better. This was determined by electrochemical impedance spectroscopy (EIS), immersion testing (3wt % NaCl) and salt fog testing. Perfect performance of undoped PAni could be understood as follows. From the high pore-resistance value observed (2-10 U) it can be concluded that PAni forms a dense, adherent, low porosity film on carbon steel. Such a film would restrict the access of components required for corrosion to occur ... 

There are other examples of applications of vegetable oil-based nanocomposites in different fields. These include soybean oil-based PU/silica nanocomposites as surface coating materials, anti-corrosive polyurethane/ OMMT coatings for carbon steel and palm oil, soybean oil and castor oil-based polyurethane nanocomposite as foams. - - - ... 

NACE Publication 6H189. A state-of-the-art report of protective coatings for carbon steel and autenitic stainless steel surfaces under thermal and cementitious fire proofing. A technical report by the national association of corrosion engineers task groups 7-H-31, 1989. 

Pickling done before coating may use a mildly acidic bath such spent liquor is not considered hazardous. Waste pickle liquor flows typically range between 10 and 20 gal/t of pickled product. Rinsewater flows may range from less than 70 gal/t for bar products to more than 1000 gal/t for certain flat-rolled products. The principal pollutants in rinsewater include TSS, dissolved iron, and metals. For carbon steel operations, the principal metals are lead and zinc for specialty and stainless steels the metals include chromium and nickel.15... 

Support spacing must be much closer than for carbon steel. As temperature increases, the allowable stress for many plastic pipes decreases very rapidly, and heat from sunlight or adjacent hot uninsiuated equipment has a marked effect. Many plastics deteriorate with exposure to ultraviolet light if not provided with a UV-resistant coating or other surface barrier. Successful economical underground use of plastic pipe does not necessarily indicate similar economies outdoors aboveground. 

Chloride stress cracking corrosion was also a problem when austenitic stainless steels were covered with thermal insulation. The NACE Paper also discusses the protective coatings for stainless steels and provides sandblasting and coating application guides for stainless and carbon steels. 

Figure 4.4.48. Bode plots for phosphated and coated 1010 carbon steel in 0.5 N NaCl solution. (From F. Mansfield, M. W. Kendig, and S. Tsai, Evaluation of Organic Coating Metal Systems by AC Impedance Techniques. Reprinted with permission from Corrosion, 38, 482 [1982], NACE, Houston, TX.)...

NASA, Standard for Protective Coating of Carbon Steel, Stainless Steel, and Aluminum on Launch Structures, Facilities, and Ground Support Equipment, NASA-STD-5008A, available at http //corrosion. ksc.nasa.gov/publications.htm. 

Figure 15.4 Mapping electrochemical material loss against mechanical erosion rates for a nonpassivating surface carbon steel (AISI1020) along with two potentially passivating surfaces of nickel aluminum bronze (NAB) one that has been thermally sprayed by high-velocity oxy-fuel deposition as a coating on carbon steel ( j and another which has been cast (A.). These results were obtained from jet impingement erosion-corrosion tests. Reprinted from Ref. [7]. Copyright (2007) with permission from Elsevier.

Coatings for carbon and Cr-Mo steels are often overlaid, and of composition corresponding to the austenitic alloys listed in Table 5-1, although several steel products are diffusion aluminized, particularly for resistance to sulBdation attack (Sivakumar and Rao, 1982 Bayer, 1995). The weld overlay process, in which an arc-welding method is used to deposit a 2-3 mm coating (i.e., clad-... 

Testers may be tempted to force quicker corrosion testing by increasing the amount of chemical stress. Steel that corrodes in a 0.05% sodium chloride (NaCl) solution will corrode even more quickly in 5% NaCl solution the same is true for zinc-coated steel. The problem is that the amount of acceleration is different for the two metals. An increase in NaCl content has a much more marked effect for zinc-coated substrates than for carbon steel substrates. Strom and Strom [1] have demonstrated this effect in a test of weakly accelerated outdoor exposure of painted zinc-coated and carbon steel samples. In this weakly accelerated test, commonly known as the Volvo Scab test, samples are exposed outdoors and sprayed twice a week with a salt solution. Table 7.1 gives the results after 1 year of this test, using different levels of NaCl for the twice-weekly spray. 

Shipment and Storage, Specifications. A/-Vinyl-2-pyrrohdinone is available in tank cars and tank trailers and in dmms of various sizes. Shipping containers are normally steel or stainless steel. Tank cars are provided with heating coils to facihtate unloading in cold weather. Rubber, epoxy, and epoxy—phenohc coatings are attacked and must be avoided. Carbon steel has been successfully used for storage tanks, but stainless steel preserves product quahty better. Aluminum and certain phenohc coatings are also satisfactory. 

Storage. Carbon steel and stainless steel should be used for all equipment in ethylene oxide service. Ethylene oxide attacks most organic materials (including plastics, coatings, and elastomers) however, certain fluoroplastics ate resistant and can be used in gaskets and O-rings. See Reference 9 for a hst of materials that are compatible with ethylene oxide. 

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