Abstract: A novel PRD (pressure relief device) design called fuse plug which is creep-resistant and leakage-free is developed to improve the thermal response of PRD to fire when it is used as a temperature safety device for valves, cylinders, pressurized pipes, or any pressure vessels, the new design being the combination of geometrical configuration of PRD structure and composite technology wherein the low-melting matrix alloy is dispersed with strong/stiff reinforcing agents such as cut-wire type aggregates/cylinders and such composite alloy is contained in a threaded/rugged cavity with the length/diameter ratio being greater than a minimum. The new design employs a disc-type seal T backed by the composite alloy, thus allowing the use of this new design for cylinders of poor thermal conductivity.

Abstract: A unique design for improved creep strength with a leakage-free structure is presented for manufacture of creep-resistant pressure relief device (PRD) of valves or cylinders or any pressure vessels as a fire protection safety device, the new design being the combination of geometrical configuration of PRD body shell and composite technology wherein the relatively weak matrix phase is dispersed with strong reinforcing agent and such composite mixture of matrix phase/reinforcing agent is contained in a nonslip structure of PRD cavity with a length/diameter ration being greater than about one such that the external load is transferred to the PRD structural body via stress transfer mechanism through reinforcing agents. The PRD's or fuse plugs fabricated by techniques of the present invention exhibit pronounced creep strength and show no gas leakage under high pressure/elevated temperature conditions realized during fires.

Abstract: A fabrication method of strengthening metallic alloys by composite technology has been developed by mixing steel shots or aggregates with conventional alloys, thus preventing cold flow or creep. Preventing creep is advantageous in thermal plugs which must withstand fluid pressure without leakage until subjected to dangerous temperatures such as caused by fire. The matrix alloy primarily consists of some or all of copper, magnesium, bismuth, tin, lead, cadmium, and indium and the particle material is preferably iron or steel. New alloys exhibit a higher strength against a hydrostatic gas pressure than that of conventional matrix phase containing no reinforcing particles, while maintaining the melting temperature of new alloys in the same range of conventional unreinforced matrix alloy. The mixing of steel particles with the matrix is achieved by employing a flux such as ammonium chloride.

Abstract: Chilled iron shots with the carbon content being about 3 weight % are mixed with zinc-based alloys containing copper at a temperature between the liquidus and solidus of the matrix phase alloy such that the matrix alloy becomes a mixture of liquid and solid phase particles. Such slurry state mixture is agitated to form a vortex and the iron shots are injected to the vortex zone. The composite zinc alloy fabricated by the preceding slurry vortex method is very economical without degrading the physical/mechanical behavior compared to conventional zinc alloys. The copper or zinc coating on iron shots tends to improve the wetting adhesion between shots and matrix alloy, thus eliminating defects at the interphase between shots and matrix phase.

Abstract: In summary of this disclosure, the present invention provides novel metal matrix fibrous composites which can be used as a fusible core in molding plastics. Modifications are possible within the scope of this invention.

Abstract: Tin-based alloys filled with steel shots or/and reinforced with short tin-coated steel fibers were prepared by melting the alloy phase and by mixing filler shots/fibers with the molten alloy in an air atmosphere with the addition of ammonium chloride. The content of steel shots ranges up to about 40 weight % and the fraction of tin-coated steel fibers ranges up to about 30 weight %. New reinforced composite alloys have a higher strength than unreinforced conventional alloys while keeping the melting temperature of new composites in the same range of unreinforced alloys.