STEELS FOR SOLID-PROPELLANT ROCKET-MOTOR CASES
Abstract
Strength requirements for solid propellant motor cases (or chambers) are reviewed and the potential gains in performance achieved by reducing weight of inert components are discussed. It is shown that substantial improvements in strength/density ratio of booster stage material are required to effect appreciable gains in performance (velocity, payload). Weight savings are much more significant when achieved in the upper stages of a rocket system than in the booster (launch) stage. Considering the case as a pressure vessel a comparison is made between titanium alloys, aluminum alloys, a composite material (fibre glass filament winding), and alloy steels on the basis of a case optimized for resistance to internal pressure (hoop stresses) and external buckling loads. Three classes of alloy steel are comprehensively discussed in order of increasing balance between yield strength and fracture toughness. The members of Group I, the low alloy medium carbon (.35-.45C) martensitic steels, are compared with each other on the basis of the yield strength-fracture toughness relations. The second class of steels (Group II) consists of the low carbon (.25%C) alloy martensites. The metallurgical design of these alloys (9 Nickel4 cobalt) is reviewed, and their improved balance fracture toughness and yield strength is discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1965
- Accession Number
- AD0612646
Entities
People
- Isaac Perlmutter
- Vincent Depierre
Organizations
- Air Force Research Laboratory