Heavy-duty coatings

Coating Systems for Corrosion Protection of Large Steel Constructions (Heavy-Duty Coatings) [ii i],[ii.2]... 

Heavy-duty coating systems generally comprise two primer coats and two topcoats, modern system sometimes consist of one primer coat and two topcoats. The total dry film thickness (DFT) of such anticorrosive paint systems is 150 - 200 pm, each layer has a minimum DFT of 40-50 pm. Due to their excellent adhesion, the first and second primers prevent corrosion of the metal surface. The pigments and extenders allow the primers to react with ions (CD and SO4") that diffuse into the film from the atmosphere. The pigmented organic film also forms a barrier against humidity that may otherwise initiate a corrosive process. 

Heavy-duty coatings are often still applied manually with brushes or rollers that completely wet the metal surface holes and pores are filled with paint. This is especially important when old, partially rusted constructions are repainted after sanding. Brushing and rolling, however, only allow a slow working speed. Larger surface areas must be painted with airless spraying equipment. 

Chem. Descrip. Urethane-modified epoxy resin in xyiene/MiBK soivs. Uses Adhesion promoter, chem. resist, aid, soiv. resist, aid in primers and heavy-duty coatings... 

The multilayer system to be used with a steel structure is determined by the required service life and the environmental conditions under which the steel structure must exist. General coating systems are applied to structures in mild environments while heavy-duty coating systems are applied to these structures in severe environments. Typical general coating systems and heavy duty coating systems are shown in Tables 12.5 and 12.6, respectively. 

Table 12.6 Heavy-Duty Coating Multilayer Paint Systems...

The scope of this book is heavy-duty protective coatings used to protect structural steel, infrastructure components made of steel, and heavy steel process equipment. The areas covered by this book have been chosen to reflect the daily concerns and choices faced by maintenance engineers who use heavy-duty coating, including ... 

The target group for this book consists of those who specify, formulate, test, or do research in heavy-duty coatings for such applications as ... 

Heavy-Duty Maintenance and Marine Coatings. Heavy-duty maintenance coatings ate appHed to bridges, off-shore drilling tigs. 

Figure 12-7. Piston rods. Precision-manufactured rolled threads and induction hardening provide high fatigue strength and long life in heavy duty service. Standard rod material is AISI 4142 carbon steel other materials are available as required. Tungsten carbide coatings are also available for maximum surface hardness. Pistons are locked securely onto the rods. For higher pressure, smaller bore cylinders, the piston may be integral with the rod. (Used by permission Bui. 85084, 1992. Dresser-Rand Company.)...

Tapes are produced in both temperate and tropical grades and heavy duty versions can be supplied for application under hot mastic asphalts at field joints of concrete weight-coated pipelines. Wrapping of complex shapes may be achieved by first profiling with a bituminous filler compound. 

Molybdenum alloys and coatings make steel particularly hardwearing for use in heavy-duty parts. 

The bluish white, hard, yet ductile, metal is inert to all acids and highly non-abrasive. Used for heavy-duty parts in electrical contacts and spinning jets. Reflectors are prepared from the mirror-smooth surfaces (e.g. head mirrors in medicine). Thin coatings provide a corrosion-resistant protective layer, for example, for jewelry, watches, and spectacle frames. The metal is a constituent of three-way catalysts. Rhodium complexes are used with great success in carbonylations (reactions with CO) and oxidations (nitric acid) in industry. Platinum-rhodium alloys are suitable thermocouples. 

The wire beads used are produced from a combination of multi-strand copper, zinc or brass coated high-tensile steel wires. The required number of wires are formed into the required shape and then passed through a cross-head extruder to be coated with rubber compound. The coated wire layers are then formed into a coiled ring and the free wire ends secured together. For certain heavy duty applications use is made of either a light weight rubberised fabric or a small fibre filled rubber sheet to cover the joint area. In some cases the bead construction is also partially vulcanised. 

A Teflon-coated, heavy duty, oval-shaped spin bar was used by the submitters for efficient stirring. 

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