Austenitic Nickel Research Articles

Structure and properties of austenitic nickel cast irons

Structure and properties of austenitic nickel cast irons

Relationship between the high-temperature radiation embrittlement of austenitic stainless steels and nickel alloys and focusing processes

Relationship between the high-temperature radiation embrittlement of austenitic stainless steels and nickel alloys and focusing processes

Corrosion Testing of Weldments

Abstract Weldments sometimes corrode preferentially in the weld metal itself or in the heat affected areas of the parent metal. The localized nature of the attack limits the usefulness of standard weight loss corrosion tests. Techniques for overcoming this limitation are discussed. The influence of specimen geometry and surface finish are dealt with as well as a variety of destructive and nondestructive methods for evaluating a corroded weldment. The advantages and limitations of the various ASTM intergranular tests for austenitic stainless, ferritic stainless, and nickel base alloys are reviewed. Guidelines for evaluating weldment corrosion are given, although it is recognized that there is no single best procedure for all situations. The use of sensitization treatments to simulate welding is discussed.

Fire and Quench Tests of Refinery Valves

Valve bodies made of seven materials from five suppliers were thermal-shock tested by heating to 1300 F, 1500 F, 1600 F, or 1800 F and then quenching with a fire-hose stream. None cracked when quenched from 1300 F. Nodular, malleable, and gray cast iron cracked when quenched from 1600 F and 1800 F, because of the combination of differential-cooling stresses and the stresses produced by the transformation of high-carbon austenite to martensite. Austenitic cast nickel iron, with either flake or spheroidal graphite, cast carbon steel, cast 5% chromium-0.5% molybdenum steel, and cast 9% chromium-1% molybdenum steel did not crack in any of the tests. Spheroidal graphite structures produced by treatment with magnesium or with yttrium behaved the same. Based on a consideration of both these results and the melting temperature of the materials, ferritic cast-steel valves are classed as safe for refinery hydrocarbon service, austenitic cast-nickel-iron valves as intermediate, and cast-iron valves of any type as not safe for this service.