Abstract Method and Product: Compacts composed of fibrils of tough, recalcitrant metals such as stainless steel; the density of the compacts being about 30 to 85 percent of the density of the metal of which the ''''fibrils'''' are composed. The fibrils range in transverse dimension from about 0.0005 to 0.005 inch, have an area less than that of a 0.002 inch circle, are of uniform length, and are made by shearing off narrow width pieces from the end of a rolled strip of parent metal. Individual fibrils have the two flat rolled faces of the parent strip and two sheared faces the width of one of the sheared faces being wider than the other as a result of shearing, so that the cross section of the fibril ranges from roughly triangular to squashed four-sided configuration with the two rolled faces converging toward the narrower of the sheared faces. Compacts are made by separating the fibrils and air lifting them against a traveling screen through which loose extraneous burrs, chips and slivers are substantially removed, thereby leaving a mat of fibrils substantially free from degraded particles which might otherwise contaminate the mat and migrate through it. The mat has excellent green strength and is compressed through several stages preferably with intermediate annealing until the densities are obtained. Compacts of varying densities throughout the thickness of the compact may be prepared. The compacts composed of the compressed mat (or layers of mat) may be supported on exterior surfaces by woven or reticulated metal support members. Extremely recalcitrant metals such as hard-to-work Type 347 Stainless Steel Alloy and similar difficulty machinable metals may be utilized for making the original fibrils. The finished compacts are useful for sophisticated filtering and the like applications and for transpiration cooled surfaces.
The machine combination comprising means for generating an elongated felt strip of substantially uniform width of hair-like metal fibrils, furnace means for heating said felt strip in an inert atmosphere to a temperature of about 2000*F for annealing the metal fibrils constituting the felt strip, means for cutting said felt strip into pieces of predetermined width and length, means for superimposing layers of said annealed felt strip so as to build a multiple layer object, means for pressing said multiple layer annealed object to force the fibrils of the layers into random contact with each other and to consolidate said object, and furnace means for heating the thus pressed object to a temperature sufficient to weld the contacting fibrils together where they contact each other.
Claim 2
Dependent Claim
125 words
The machine combination comprising means for generating an elongated felt strip of substantially uniform width of hair-like metal fibrils, furnace means for heating said felt strip in an inert atmosphere to a temperature of about 2000*F for annealing the metal fibrils constituting the felt strip, means for cutting said felt strip into pieces of predetermined width and length, means for superimposing layers of said annealed felt strip so as to build a multiple layer object, means for pressing said multiple layer annealed object to force the fibrils of the layers into random contact with each other and to consolidate said object, and furnace means for heating the thus pressed object to a temperature sufficient to weld the contacting fibrils together where they contact each other.
Claim 3
Dependent Claim
30 words
The machine combination of claim 1 further characterized in that said means for superimposing layers comprises means for rolling an elongated piece of said felt strip into a cylindrical object.
Claim 4
Dependent Claim
33 words
The machine combination of claim 1 further characterized in that means is provided for rolling the felt strip to reduce its thickness and increase its density prior to annealing in an inert atmosphere.
Claim 5
Dependent Claim
35 words
The machine combination of claim 1 further characterized in that means is provided for rolling the felt strip to reduce its thickness and increase its density after passing said strip through said annealing furnace means.
Claim 6
Dependent Claim
31 words
The machine combination set forth in claim 1 including conveyor means for moving the felt strip continuously through the machines of the combination to said means for cutting the felt strip.
Claim 7
Dependent Claim
33 words
The combination of claim 1 further including means for securing the multiple layer object formed of fibrils to a metal reinforcement performed prior to the furnace means for heating to a welding temperature.