Direct chill metal casting apparatus and technique

Claim 2

In the process of direct chill casting a metal in an open ended mold cavity having a support telescoped in the discharge end thereof and an opening at the other end thereof whose diameter is smaller than the peripheral wall of the cavity so that the inner peripheral edge of said other end opening forms an overhang relatively over the wall, the steps of: continuously filling said other end opening of the cavity with molten metal so that the mass of molten metal splays about the inner peripheral edge of the other end opening and forms a body of molten metal in the cavity whose cross-section has a divergent/convergent outline between the ends thereof, the intermediate continuum of which between the planes of maximum divergence and minimum convergence thereof, has a peripheral outline corresponding generally to the outline of the cavity at the peripheral wall thereof, circumposing graphite or graphite-like wall defining means about the molten metal body in the peripheral wall of the cavity at a level below the overhang adapted so that the intermediate continuum is surrounded by a solid but fluid permeable wall section of said means, simultaneously forcing a lubricating oil and an additional fluid medium selected from the group consisting of a highly heat vaporizable liquid medium and a gaseous medium, through the fluid permeable wall section so that the oil and additional fluid medium discharge into the cavity at points on the inner peripheral surface of the wall section opposite the intermediate continuum, and simultaneously chilling the molten metal body from points below the intermediate continuum and reciprocating the mold and support in relation to one another endwise of the cavity to elongate the body, the wall of the cavity co-terminating with the overhang at the aforesaid other end of the cavity so that the part of the molten metal body directly adjacent the overhang is surrounded by a closed corner of the cavity, and the fluid thus discharged about the intermediate continuum forming an annulus of fluid tending to flow relatively away from the closed corner of the cavity toward the discharge end thereof.

Claim 3

The process according to claim 1 wherein a stream of fluid is impinged on the molten metal body at a level below the plane of minimum convergence, to chill the body, and that part of the body disposed between the level of impingement and the aforesaid fluid permeable wall section, is surrounded by a section of the wall which is impermeable to said fluid.

Claim 4

The process according to claim 1 wherein the oil and additional fluid medium are forced into the fluid permeable wall section through the outer peripheral portion thereof.

Claim 5

The process according to claim 3 wherein the additional fluid medium is a gas, and the oil and gas are forced into the fluid permeable wall section at levels spaced apart from one another endwise of the cavity.

Claim 6

The process according to claim 4 wherein the oil and gas are forced into the fluid permeable wall section through a pair of spaced circumferential grooves extending about the wall section at the outer periphery surface.

Claim 7

The process according to claim 5 wherein the grooves have sets of holes extending peripherally inwardly therefrom, but terminating in the wall section short of the inner peripheral surface thereof.

Claim 8

The process according to claim 1 wherein the graphite or graphite-like wall defining means are circumposed about the molten metal body at a level adapted so that the part of the body directly adjacent the overhang is also surrounded by the fluid permeable wall section, and the oil and gas are forced into the wall section at levels adjacent the overhang and the plane of minimum convergence, respectively.

Claim 9

The process according to claim 1 wherein the fluid permeable wall section extends beyond the overhang in the endwise direction of the cavity, and has a step therein which is directed peripherally inwardly of the wall to define a portion of the overhang, and wherein the oil is forced into the wall section at a level adjacent the step.

Claim 10

The process according to claim 1 wherein the corner is curved opposite the meniscus to control the size of the discharge pocketed therebetween.

Claim 11

The method according to claim 1 wherein the mold cavity is disposed so that the end openings thereof are centered on a vertical line.

Claim 12

Apparatus for direct chill casting a metal comprising: means defining an open ended mold cavity having a discharge end adapted to have a support telescoped therein, and having an opening at the opposing end thereof whose diameter is smaller than the peripheral wall of the cavity so that the inner peripheral edge of said opposing end opening forms an overhang relatively over the peripheral wall, whereby when said opposing end opening of the cavity is continuously filled with molten metal, the mass of molten metal splays about the inner peripheral edge of the opposing end opening and forms a body of molten metal in the cavity whose cross-section has a divergent/convergent outline between the ends thereof, the intermediate continuum of which between the planes of maximum divergence and minimum convergence thereof, has a peripheral outline corresponding generally to the outline of the cavity at the peripheral wall thereof, means for chilling the molten metal body from points below the intermediate continuum, graphite or graphite-like wall defining means disposed in the peripheral wall of the cavity at a level below the overhang for surrounding the intermediate continuum of the molten metal body by a solid but fluid permeable wall section, and fluid delivery means for simultaneously forcing a lubricating oil and an additional fluid medium selected from the group consisting of a highly heat vaporizable liquid medium and a gaseous medium, through the fluid permeable wall section so that the oil and additional fluid medium discharge into the cavity at points on the inner peripheral surface of the wall section opposite the intermediate continuum, while the molten metal body is chilled and the mold and support are reciprocated in relation to one another endwise of the cavity to elongate the body, the wall of the cavity co-terminating with the overhang at the aforesaid opposing end of the cavity so that the part of the molten metal body directly adjacent the overhang is surrounded by a closed corner of the cavity, and the fluid thus discharged about the intermediate continuum forming an annulus of fluid tending to flow relatively away from the closed corner of the cavity toward the discharge end thereof.

Claim 13

Apparatus for direct chill casting a metal comprising: means defining an open ended mold cavity having a discharge end adapted to have a support telescoped therein, and having an opening at the opposing end thereof whose diameter is smaller than the peripheral wall of the cavity so that the inner peripheral edge of said opposing end opening forms an overhang relatively over the peripheral wall, whereby when said opposing end opening of the cavity is continuously filled with molten metal, the mass of molten metal splays about the inner peripheral edge of the opposing end opening and forms a body of molten metal in the cavity whose cross-section has a divergent/convergent outline between the ends thereof, the intermediate continuum of which between the planes of maximum divergence and minimum convergence thereof, has a peripheral outline corresponding generally to the outline of the cavity at the peripheral wall thereof, means for chilling the molten metal body from points below the intermediate continuum, graphite or graphite-like wall defining means disposed in the peripheral wall of the cavity at a level below the overhang for surrounding the intermediate continuum of the molten metal body by a solid but fluid permeable wall section, and fluid delivery means for simultaneously forcing a lubricating oil and an additional fluid medium selected from the group consisting of a highly heat vaporizable liquid medium and a gaseous medium, through the fluid permeable wall section so that the oil and additional fluid medium discharge into the cavity at points on the inner peripheral surface of the wall section opposite the intermediate continuum, while the molten metal body is chilled and the mold and support are reciprocated in relation to one another endwise of the cavity to elongate the body, the wall of the cavity co-terminating with the overhang at the aforesaid opposing end of the cavity so that the part of the molten metal body directly adjacent the overhang is surrounded by a closed corner of the cavity, and the fluid thus discharged about the intermediate continuum forming an annulus of fluid tending to flow relatively away from the closed corner of the cavity toward the discharge end thereof.

Claim 14

The apparatus according to claim 11 wherein the fluid delivery means are operable to force the oil and additional fluid medium into the fluid permeable wall section through the outer peripheral portion thereof.

Claim 15

The apparatus according to claim 12 wherein the fluid delivery means are operable to force oil and gas into the fluid permeable wall section at levels spaced apart from one another endwise of the cavity.

Claim 16

The apparatus according to claim 13 wherein there is a pair of spaced circumferential grooves extending about the wall section at the outer periphery thereof, and the fluid delivery means are operable to force the oil and gas into the wall section through the grooves.

Claim 17

The apparatus according to claim 14 wherein the grooves have sets of holes extending peripherally inwardly therefrom, but terminating in the wall section short of the inner peripheral surface thereof.

Claim 18

The apparatus according to claim 11 wherein the graphite or graphite-like wall defining means are disposed in the wall of the cavity at a level adapted so that the part of the body directly adjacent the overhang is also surrounded by the fluid permeable wall section, and the fluid delivery means are operable to force the oil and gas into the wall section at levels adjacent the overhang and the plane of minimum convergence, respectively.

Claim 19

The apparatus according to claim 11 wherein the fluid permeable wall section extends beyond the overhang in the endwise direction of the cavity, and has a step therein which is directed peripherally inwardly of the wall to define a portion of the overhang, and the fluid delivery means are operable to force the oil into the wall section at a level adjacent the step.

Claim 20

The apparatus according to claim 11 wherein the corner is curved opposite the meniscus to control the size of the discharge pocketed therebetween.

Claim 21

The apparatus according to claim 11 wherein the mold cavity is disposed so that the end openings thereof are centered on a vertical line.

Claim 22

The apparatus according to claim 11 wherein the overhang is defined by an insulative refractory member, and the member and wall section are disposed so that they abut one another at the overhang.

Claim 23

The apparatus according to claim 20 wherein the aforesaid opposing end opening of the cavity is defined by an insulative refractory scupper for a hot top, and the scupper is centrally located within the overhang defining member.

Claim 24

The apparatus according to claim 11 wherein the fluid permeable wall section is annular and has a cylindrical inner peripheral surface.

Claim 25

The apparatus according to claim 11 wherein the graphite or graphite-like wall defining means take the form of a circumferentially continuous ring of graphite.

Claim 26

The apparatus according to claim 11 wherein the means for chilling the molten metal body include means for impinging a stream of fluid on the body at a level below the plane of minimum convergence, and wherein that part of the body disposed between the level of impingement and the aforesaid fluid permeable wall section, is surrounded by a section of the wall which is impermeable to said fluid.

Claim 27

The apparatus according to claim 24 wherein the diameter of the inner peripheral surface of the fluid permeable wall section is smaller than the diameter of the inner peripheral surface of the fluid impermeable section of the wall.