RESTRICTED NATIONAL ADVISORY COWTTEE FC'R ARRONKUTICS

Tests were conducted on 5 uncoated steels and on 20 steels with various'coatings to determine the effect of temperature on the tensile properties and surface characteristics of the metals. The metals were subjected to furnace-heating tests over a range of tem-peratures from 1000 ° F to 2000 ' F for 2$, 5, 15, and 60 minutes and to flame-imningement and airplane-fire tests. The surface oxides formed at different temperatures were noted and the-tensile strength and ductility of the metals determined'for the various temperatures. and periods of heating. The tests she-tied the following results: 1. In general, all materials investigated were capable of with-standing exposure to temperatures not exceeding 1700 ' F for periods up to 1s minutes without a serious deterioration in tensile prop-erties. 2. Stainless steel proved to be the best of the uncoated mate-rials tested; low carbon steels containing 1 percent silicon were better than steels tithout silicon.. ' 3. Stainless-clad plain carbon steel exhibited very little change in properties over the most severe heating conditions. 4. Chromium-nickel-alloy coatings and aluminum coatings on plain carbon steel sheets proved to be more resistant to high tern-peratures for periods of exposure up to 6C minutes than did coatings of zinc or of zinc over nickel. INTRODUCTIOM As a result of the shortage of critical materials, such as steel alloys containing nickel, an investigation was conducted by the National Bureau of Standards with cooperation from the Civil Aeronautics Administration to find satisfactory materials to replac