SEDL / STP / STP1040-EB / STP24920S

Promoted Combustion of Nine Structural Metals in High-Pressure Gaseous Oxygen; A Comparison of Ranking Methods

Steinberg, TA
research engineer with Lockheed-ESCaerospace engineer with NASAsenior scientist with Lockheed-ESC, NASA White Sands Test Facility, Las Cruces, NM

Rucker, MA
research engineer with Lockheed-ESCaerospace engineer with NASAsenior scientist with Lockheed-ESC, NASA White Sands Test Facility, Las Cruces, NM

Beeson, HD
research engineer with Lockheed-ESCaerospace engineer with NASAsenior scientist with Lockheed-ESC, NASA White Sands Test Facility, Las Cruces, NM

Pages: 22    Published: Jan 1989

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Abstract

Nine structural metals were evaluated for relative nonflammability, in a high pressure oxygen environment. The metals studied were: 316, 321, 440C and 17-4 PH stainless steels (SS), Inconel 600, Inconel 718, Waspaloy, Monel 400, and Aluminum 2219. A comparison is made between four methods which have been used to provide a relative flammability ranking of metals. A new relative ranking method is presented. Limitations of the ranking methods are assessed by investigating the effects of changes in test pressure, sample diameter, type of promoter, and sample configuration. Ranking methods which apply velocity as the primary ranking criterion are found to be limited by diameter effects. Methods which apply extinguishing pressure as the ranking criterion are found to be non-selective for metals with similar flammabilities. An overall ranking in agreement with all methods considered, for the metals described in this report, over a range of pressures and diameters, in order of combustion resistance, is: 1) Monel 400; 2) Inconel 600; 3) 316 SS, Waspaloy, Inconel 718, 17-4 PH SS, 440C SS, 321 SS; and 4) Aluminum 2219. Distinction is possible for metals in the third position; however, the relative ranking depends on the method chosen.