HIGH ENERGY RATE DENSIFICATION AND FORMING OF METAL POWDERS.
Abstract
The object of the original program (Part I) was to (1) develop a production method for slip casting thin-walled shapes from tungsten power and (2) improve the properties of powder forms by High Energy Rate Densification (pneumatic-mechanical and chemical explosive) processes. A slip casting method for tungsten was developed, but attempts to HER densify powder forms were unsuccessful. The program was then revised (Part II) to develop a manufacturing method for forming parts from powdered metals or alloys directly by using HER techniques. The basic HER method developed involves (1) RT compaction of the powder to form a 'briquette' and (2) extruding or forging this briquette after preheating to the final shape desired. Optimized techniques were developed for briquetting, free extruding, and closed cavity extruding 4600 steel-graphite, 18-9 steel, and nickel-thoria powder. Photomicrographic analysis and tensile test data was obtained on all specimens. Data indicates that 4600 steel-0.20% graphite HER extrusions or closed cavity specimens had ultimate tensile strengths 15% greater than commercial 4620 steel. Nickel-thoria HER powder specimens had room temperature strengths much higher than comparable commercial material--38% higher for extrusions and 17% for closed cavity tensile specimens. HER formed nickel-thoria specimens had much lower hot strength (1600 - 1900 F) than the commercial product which is cold drawn. Two production-type parts were made using 4600 steel-graphite and nickel-thoria powder--one by extrusion and one by forging techniques. Although the parts as made had minor flaws, the feasibility of making small production parts by the HER technique was demonstrated. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1966
- Accession Number
- AD0803172
Entities
People
- Wallace S. Hay
Organizations
- General Dynamics