Dip casting method using transpirationally cooled mold cavity

Claim 2

A process for forming intricate, thin-sectioned castings from a metal melt comprising the steps of: a. providing a die comprising a porous metal body, an impervious, low thermally conductive layer on the body sealing off the surface of the body and a mold cavity in said body opening through said layer; b. heating said layer to a temperature where the melt-metal is readily shed from the outer surface of the layer after leaving the melt; c. passing a cooling gas through said porous metal body and out the walls of said cavity to cool the cavity walls below the solidification temperature of said melt-metal; d. immersing said die into said melt to fill said cavity with melt; e. removing the die from the melt and shedding any melt-metal from said outer surface of the layer thereby carrying away from the melt only the metal solidified in said cavity; and f. stripping the casting from the cavity.

Claim 3

A process for forming intricate, thin-sectioned, age-hardenable, lead-acid storage battery grids from a lead alloy melt comprising the steps of: a. providing a die comprising a porous metal body, an impervious, low thermally conductive layer on the body sealing off the surface of the body and a grid-forming mold cavity in said body opening through said layer; b. heating said layer to a temperature where the lead alloy is readily shed from the outer surface of the layer after leaving the melt; c. while maintaining said layer at such a temperature, passing a cooling gas through said porous metal body and out the porous walls of said cavity to cool the cavity walls below the solidus temperature of said lead alloy; d. immersing the thusly prepared die into a lead alloy melt containing less than about three percent antimony to a sufficient depth for said melt to fill said cavity; e. quenching said lead alloy in said cool cavity at a sufficiently rapid rate to obtain a supersaturated solid solution of the alloy ingredients in the lead; f. removing the die from the melt and shedding any melt-metal from said outer surface of the layer thereby carrying away from the melt only the metal solidified in said cavity; g. stripping the thusly formed grid from the cavity; and h. allowing the thusly formed grid to age and strengthen.

Claim 4

A process for forming intricate, thin-sectioned, age-hardenable, lead-acid storage battery grids from a lead alloy melt comprising the steps of: a. providing a die comprising a porous metal body, an impervious, low thermally conductive layer on the body sealing off the surface of the body and a grid-forming mold cavity in said body opening through said layer; b. heating said layer to a temperature where the lead alloy is readily shed from the outer surface of the layer after leaving the melt; c. while maintaining said layer at such a temperature, passing a cooling gas through said porous metal body and out the porous walls of said cavity to cool the cavity walls below the solidus temperature of said lead alloy; d. immersing the thusly prepared die into a lead alloy melt containing less than about three percent antimony to a sufficient depth for said melt to fill said cavity; e. quenching said lead alloy in said cool cavity at a sufficiently rapid rate to obtain a supersaturated solid solution of the alloy ingredients in the lead; f. removing the die from the melt and shedding any melt-metal from said outer surface of the layer thereby carrying away from the melt only the metal solidified in said cavity; g. stripping the thusly formed grid from the cavity; and h. allowing the thusly formed grid to age and strengthen.

Claim 5

The process according to claim 2 wherein said alloy contains less than 1 percent antimony.

Claim 6

A process for forming intricate, thin-sectioned, age-hardenable, lead-acid storage battery grids from a lead alloy melt comprising the steps of: a. providing a die comprising a porous metal body, an impervious, low thermally conductive layer on the body sealing off the surface of the body and a grid-forming mold cavity in said body opening through said layer; b. heating said layer to a temperature where the lead alloy is readily shed from the outer surface of the layer after leaving the melt; c. passing a cooling gas through said porous metal body and out the walls of said cavity to cool the cavity walls below the solidus temperature of said lead alloy; d. immersing said die into a lead alloy melt containing less than about 1 percent antimony while drawing a vacuum behind said Porous metal body to suck said melt into said cavity; e. quenching said lead alloy in said cool cavity at a sufficiently rapid rate to obtain a supersaturated solid solution of the alloy ingredients in the lead; f. removing the die from the melt and shedding any melt-metal from said outer surface of the layer thereby carrying away from the melt only the metal solidified in said cavity; g. blowing a cooling gas through said porous metal body and out the walls of said cavity to strip the thusly formed grid from the cavity and commence cooling of the cavity walls; and h. allowing the thusly formed grid to age and strengthen.

Claim 7

A process for forming intricate, thin-sectioned, age-hardenable, lead-acid storage battery grids from a lead alloy melt comprising the steps of: a. providing a die comprising a porous metal body, an impervious, low thermally conductive layer on the body sealing off the surface of the body and a grid-forming mold cavity in said body opening through said layer; b. heating said layer to a temperature where the lead alloy is readily shed from the outer surface of the layer after leaving the melt; c. passing a cooling gas through said porous metal body and out the walls of said cavity to cool the cavity walls below the solidus temperature of said lead alloy; d. immersing said die into a lead alloy melt containing less than about 1 percent antimony while drawing a vacuum behind said Porous metal body to suck said melt into said cavity; e. quenching said lead alloy in said cool cavity at a sufficiently rapid rate to obtain a supersaturated solid solution of the alloy ingredients in the lead; f. removing the die from the melt and shedding any melt-metal from said outer surface of the layer thereby carrying away from the melt only the metal solidified in said cavity; g. blowing a cooling gas through said porous metal body and out the walls of said cavity to strip the thusly formed grid from the cavity and commence cooling of the cavity walls; and h. allowing the thusly formed grid to age and strengthen.

Claim 8

A dip casting die comprising: a. a porous metal body adapted to the transpirationally cooled; b. an impervious, low thermally conductive layer on the body sealing off the surface of the body; c. a mold cavity having porous walls in said body opening through said layer; and d. means for introducing cooling gas into said porous metal body for exiting through and transpirationally cooling the porous walls of said cavity.

Claim 9

A dip casting die comprising: a. a porous metal body adapted to the transpirationally cooled; b. an impervious, low thermally conductive layer on the body sealing off the surface of the body; c. a mold cavity having porous walls in said body opening through said layer; and d. means for introducing cooling gas into said porous metal body for exiting through and transpirationally cooling the porous walls of said cavity.