Stress-Aging: A New Treatment for Alloys. Part III. Effect on Standard Tensile Properties of Four Ultra-High-Strength Steels

摘要

Stress-Aging (a new treatment) effects considerable improvement in standard strength properties for four Ultra-High-Strength Steels, (4340 Air-Melted, 4340 VacuumMelted, 4335 Si-Modified and 300M), without effective concurrent losses of elongation, reduction of area, or relative toughness. Respectively, stress-aging results in the following increases in strenth properties: (a) Proportional limit: 42,300; 37,300; 72,500; and 75,000 psi; (b) Elastic capacity: 48%, 36%, 100% and 90%; (c) 0.1% offset yield strength: 40,000; 35,000; 56,500; and 62,000 psi. These properties are in parallel with the direction of the externally applied elastic stress. It is conjectured that these increases in strength properties may be due to straininduced (sub-micron) precipitation of nickel-silicides and increased carbides, reacting with dislocations. (Author)