This specification covers the basic requirements for a corrosion resistant coating consisting of an electrodeposited Nickel Cobalt alloy on fasteners. It is principally electrodeposited to steel products. It can also be electrodeposited on iron, stainless steel, aluminum, titanium and any other metal substrate. The coating thickness ranges from 15 to 25 (microns), No oversizing of nuts or under sizing of studs is required to compensate for coating thickness. The coating consists of a Nickel Cobalt alloy and is for service where operating temperature does not exceed the following range -200C to 700C (-328F to 1292F). The Nickel Cobalt alloy coating has a wider temperature range than Zinc, Organic polymer resins and Cadmium coated fasteners, that have a limited maximum temperature of 210C (410F) for Zinc, 230C (446F) for Organic polymer resins and 160C (320F) for Cadmium. Warning: Cadmium is toxic; the cadmium coating should not be used at high temperatures, because cadmium will form toxic fumes. Lubrication is not required as the Nickel Cobalt alloy coating has a low coefficient of friction that reduces the tightening torque required and allows repetitive dismantling of fasteners. The low coefficient of frictions also prevents galling on threads. The Nickel Cobalt alloy coating offers a corrosion resistance superior to Cadmium, Zinc and Organic polymer resins, averaging 50 times less corrosion rate in ASTM G59 Electrochemical Testing. The corrosion resistance of the Nickel Cobalt alloy coating measured in hours of exposure to the Salt Spray (Fog) ASTM B 117 and the CASS Test ASTM B 368, show a range of 5 to 10 times more hours compared to Cadmium, Zinc and Organic polymer resins. The wood industry applies ACQ (alkaline copper Quaternary) treatment to prevent degradation in wood products. This treatment generates an aggressive corrosive environment that corrodes rapidly Zinc, Cadmium and Organic polymer resins coated fasteners. The Nickel Cobalt Alloy provides an excellent corrosion resistance to this treatment.
As a reference standard specification to establish the requirements to be satisfied. It would be used by design engineers for ease of specification in new projects. It would be used by applicators to satisfy requirements and provide consistent, quality standards. It would be used by institutions for recommendations on new coatings. It would be used by original equipment manufacturers to satisfy requirements. It would be used by purchasing agents to set the standard to quote the same products and performance. It would be used by end users to order the coating and verify the final product to a known standard when receiving the product. It would also set the Standard Test Method to receive the coatings and verify that the Standard Specification is satisfied.
Keywordscorrosion protection, oil and gas fasteners, offshore, sub sea, topside, subsea, wood acid oxidation electrodeposited, plating, plated, galvanic corrosion, saline solution, sea water, marine environment, chemical , sulfur, sufidric acid, H2S, hydrogen embrittlement, nickel electroless, low temperature, Auto catalytic nickel, autocatalytic nickel, interior coating, abrasion, torque, heat diffuser, anode , catodic protection, pipeline, valves, clamps, flanges, christmas tree, heat exchangers, gas lines, water tanks, liquid containers,
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
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