Paint coatings steel panels

D2201—99(2011) Standard Practice for Preparation of Zinc-Coated and Zinc-Alloy-Coated Steel Panels for Testing Paint and Related Coating Products... 

A Mossbauer spectroscopic study on mst formed under coated steel panels exposed to a marine environment for 18 months showed the presence of y-Fe203, aFeOOH, and yFeOOH next to the paint surface. The rust at the steel interface consisted primarily of yFeOOH. The coatings used for the different tests were the following ... 

B.S.l. Phosphate Coatings (Drafting) Panel, Phosphate Coatings as a Basis for Painting Steel , J. Iron St. Inst., 170, 10 (1952)... 

Table 11(A). Outdoor and laboratory tests of paint coatings applied over ASa 3 steel panels.

Steel objects, when exposed to humid atmospheres or when immersed in electrolytes, corrode at a rapid rate. For example, abrasively polished, cold-rolled steel panels will show signs of rust within 15 minutes when immersed in dilute chloride solutions with pH in the range of 7-10. One of the methods used to control this rapid corrosion is to coat the metal with a polymeric formulation such as a paint. The role of the paint is to serve primarily as a barrier to environmental constituents such as water, oxygen, sulfur dioxide, and ions and secondarily as a reservoir for corrosion inhibitors. Some formulations contain very high concentrations of metallic zinc or metallic aluminum such that the coating provides galvanic protection as well as barrier protection, but such formulations are not discussed in this paper. 

Test Site. The second phase of this investigation was conducted in the hangar deck structure. The walls and floor of the compartment are of brick, the roof is of steel. The front is designed with ten equidistantly spaced 3-foot-square portholes, arbitrarily numbered from 1 to 10, from left to right, when facing the structure. Tests were conducted on painted 1/8 inch thick steel panels which were fitted over the ports flush with the inner wall, painted surface toward the outside. The initial series of tests was conducted on panels with a dry film thickness of 3 to 5 mils (representative of two top coats) the second series of tests was determined on panels with a dry film thickness of over 5 mils (representative of four top coats). 

A 1974 study by Campbell al. (12) involved both laboratory and field exposure of five coating systems on stainless steel panels oil-based house paint latex house paint industrial main-... 

A major problem in automotive vehicles is corrosion control, particularly in the northern areas of the country where salts are used to melt road ice. Protection of exposed steel from corrosion is accomplished by electroplating with copper-nickel-chromium films, particularly on trim and finish moldings. Electrophoretic painting of body panels is used industry-wide, and electrogalvanizing to protect steel under paint is soon to become a standard practice for all vehicles. Electrochemical accelerated tests for the integrity of coatings and for the determination of the concentration of coolants are used extensively. 

The most important change in materials over the years has been the transition from uncoated mild steel to zinc pre-coated steel and other corrosion-resistant metals. Hot-dip galvanized steels were used in the early stages in the motor vehicle industry. Hot-dipped galvanized steels were corrosion resistant but had a spangled surface that resulted in poor appearance after painting. Hot-dipped galvanized steel is still used on most body parts and interior surface of body outer panels. 

Once you ve repaired a ding, scratch, or dent, it s time to paint over the repair. The layers of auto body paint go from steel panel, to primer, to color, to clear coat. If you re looking to repaint a scratch, first check the depth of the scratch. What color is it If you see the car s color, follow the sanding instructions on page 371 and then just apply a layer of clear coat. If you see primer that is different from the car s color, apply color and clear coat. If you see bare steel (or very discolored plastic), you ll have to apply all three. Unless you have an unusual car, your auto shop should have the matching paint. 

One of the applications of CCTP polymers and macromonomers has been in the automotive industry. Typically, automobile steel panels require several paint layers to achieve hardwearing coatings. The first layer is commonly an inorganic mst proofing zinc or iron phosphate layer. Primer comprises... 

Knife test (KNF) The test is done by making two intersecting scratches through the paint film to the substrate with a sharp steel knife. Adhesive or cohesive failures are evaluated by peeling the coating from the intersection point and outwards. Common for the three adhesion evaluation methods are that the test is performed on immersed and non- immersed panel-half (referred to as respectively "wet" and "dry" adhesion). The type of rupture is reported, and the severity is judged on a scale from 5 (perfect) to 0 (poor). 

Annex II lists all those materials and components that are exempt from 4(2) (a). Eor example lead as an element (i.e. steel upto 0.35% lead by weight, aluminium, copper), lead compounds in components (i.e. batteries, petrol tank coatings, vibration dampers, stabilisers in protective paint), hexavalent chromium (used as coating on various key vehicle components) and mercury (as can be found in bulbs and instrument panel displays). As ruled in 4(2) (b), the Commission shall regularly amend Annex II, i.e. review all substances that are currently exempt from 4(2) (a). If the use of any of the materials or compounds listed in Annex II can be avoided, those substances will be deleted from this Annex. 

Mineral wool/cement board—Perforated and solid sheet metal and ladder-type cable trays can be completely enclosed with 1 in (25 mm) minimum thickness mineral wool/cement board panels, or equivalent. The panels should be secured with stainless steel screw and stainless steel bands in (19 mm) wide by 0.02 in (0.5 mm) thick, located no more than 18 in (450 mm) apart. In freezing climates the fireproofing panels should be given a weatherproof coat of paint. The structural strength of the metal cable tray should be adequate to support the weight of the fireproofing. 

Figure 7. Paint adhesion loss in salt spray exposure (ASTM B117) as a function of ester content for chain-extended epoxy-amine and epoxy-ester resin based coatings. All coatings applied at 20-25 urn film thickness to SAE 1010 steel test panels, baked, scribed and exposed for 24 hours to salt spray conditions.

Protective Coatings. A variety of protective coatings is available for steel in sea-water service. For such applications as ships hulls, normal practice is to apply compatible antifouling paint over the corrosion-resistant primer coating system. Figure 4 shows panels which have resisted fouling for a year or more as compared with adjacent panels where the experimental coating is not protective. 

In the winter of 1984-1985, test samples on Plexiglass plates were exposed in each of the test cities. These included samples of bare weighed auto-body steel, weighed galvanized steel, and painted auto-body steel with stainless steel trim. Where painted panels were involved, cut edges were coated in the stainless steel trimmed panels, the ends of the stainless steel bolts used for electrical continuity were coated as well. Nylon bolts were used to attach the other test specimens to the Plexiglass plate which was mounted on the front bumper of an automobile. 

The built-in costs of corrosion of automobiles were identified as corrosion protection for steel body panels such as metallic zinc coatings, paint, adhesives and sealants, nonferrous metals, corrosion-resistant materials, rust-proofing heat exchanger components, mufflers, and tail pipe corrosion. The greatest impact on the cost of corrosion for automobiles was the adverse effect of corrosion on the cost of replacement of the automobile. Both the lO model and focused sector study showed that in both models the cost of replacement of the automobiles dominated the total cost and avoidable cost estimation. 

The effect of changes in materials in automobiles that contained body panels made from carbon steel, steel pre-painted with zinc-rich primer, or steel coated with zinc/zinc alloy. The data in Table 4.38 were obtained from 5- to 6-year-old vehicles in 1985 and 1993. 

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