Riser sleeve, method for producing a riser body for the riser sleeve as well as an expander element and core box for producing a riser body

Abstract

A riser sleeve (1) for using when pouring metals into a casting mould includes a riser body (2). The riser body (2) includes a riser cavity (3) for holding liquid metal and a riser opening (4) for joining the riser cavity (3) to a mould cavity of the casting mould during the casting process. The riser cavity (3) has a greater diameter than the diameter of the riser opening (4) in at least one portion, the riser body (2) is made of an insulating and/or exothermic riser material. The riser body (2) is formed as a single piece, the riser opening (4) defines an axis (5), and the riser cavity (3) is asymmetric to the axis (5).

Claims

1. Method for producing a single-piece riser body (2) of a riser sleeve (1), comprising the following steps: forming at least one first partial cavity in a first box and a second partial cavity in a second box, bringing together at least the first box and the second box so that the at least one first partial cavity and the second partial cavity form a cavity with an inner wall (18), wherein the inner wall (18) at least partially forms an outer contour of the riser body (2) to be produced, setting an expander element (7) into the cavity, wherein the expander element (7) is configured for producing the riser body (2) in a core box, wherein the expander element (7) comprises a fixed mandrel (9) and a flexible membrane (10) that is attached to the mandrel (9), wherein an outer contour of the expander element (7) is reversibly expandable between an unexpanded state and an expanded state and wherein the outer contour of the expander element (7) extends along a central longitudinal axis (8) in the unexpanded state, wherein the flexible membrane is expanded by introducing a fluid into an intermediate space (11) between the membrane (10) and the mandrel (9), and further wherein the expander element (7) is characterized in that the expander element (7), in the expanded state of the expander element (7), has an asymmetrical outer shape with reference to the longitudinal axis (8); expanding the expander element (7) so that the expanded expander element (7) has the asymmetrical outer shape, introducing an exothermic and/or insulating riser material between the expanded expander element (7) and the inner wall (18) of the cavity for formation of the riser body (2), wherein the expanded expander element (7) specifies a shape of a riser cavity (3), constricting of the expander element (7), removing the expander element (7) out of the riser body (2) by means of a relative movement between the expander element (7) and the riser body (2), wherein the constricted expander element (7) is moved out through a riser opening (4) formed during the introducing step.

2. Method according to claim 1, wherein the expanding of the expander element (7) takes place in one direction and no expanding takes place in an opposing direction.

3. Expander element (7) that is configured for production of a riser body (2) in a core box, wherein the expander element (7) comprises a fixed mandrel (9) and a flexible membrane (10) that is attached to the mandrel (9), wherein an outer contour of the expander element (7) is reversibly expandable between an unexpanded state and an expanded state and wherein the outer contour of the expander element (7) extends along a central longitudinal axis (8) in the unexpanded state, wherein the flexible membrane is expanded by introducing a fluid into an intermediate space (11) between the membrane (10) and the mandrel (9), and further wherein the expander element (7) is characterized in that the expander element (7), in the expanded state of the expander element (7), has an asymmetrical outer shape with reference to the longitudinal axis (8).

4. Expander element (7) according to claim 3, wherein the asymmetrical expanded expander element (7) has a minimal point (17) on an expanded surface, which comprises a smaller distance to the longitudinal axis (8) than points that are axially adjacent in both directions on the expanded surface.

5. Expander element (7) according to claim 3, wherein the expander element (7) has a rectangular-shaped cross-section with parallel side walls (13) in the unexpanded state.

6. Expander element (7) according to claim 3, wherein the membrane (10) is attached with its peripheral edges (12) to the mandrel (9) both in the axial direction as well as in a circumferential direction.

7. Expander element (7) according to claim 3, wherein the membrane (10) on its inner side in an expanded region is connected to the mandrel (9) in such a way that expansion of the membrane (10) is limited locally.

8. Expander element (7) according to claim 3, wherein the membrane (10) is arranged only on a side wall (13) of the expander element (7).

Description

(1) The invention as well as the technical field are explained based on the figures as an example. Schematically, the figures show

(2) FIG. 1 a lateral view of an expander element in an initial state,

(3) FIG. 2 the expander element in an expanded state,

(4) FIG. 3 an expanded expander element with a riser body and

(5) FIG. 4 the riser body as an inherent component of a riser sleeve.

(6) FIG. 1 shows an expander element in an unexpanded state. The expander element 7 comprises a mandrel 9 and a membrane 10. The expander element 7 extends along a longitudinal axis 8 from a base 14 to a free end 15.

(7) The cross-sectional shape of the unexpanded expander element 7 is rectangular, wherein the membrane 10 only extends across a side wall 13 of the mandrel 9. The membrane 10 is completely attached to the mandrel with its peripheral edge 12. Due to lines in the inside of the mandrel 9 (not shown), it is possible to convey a fluid into an intermediate space 11 between the mandrel 9 and the membrane 10 so that the membrane 10 and, thereby, the outer contour of the expander element 7 are expanded.

(8) The accordingly expanded expander element is shown in FIG. 2. It is clear that the membrane 10 has only expanded into the direction shown left in FIG. 2 and not into the opposite right direction. In accordance with this, the expander element 7 has an asymmetrical shape with reference to the longitudinal axis 8. By connecting the membrane 10 to a surface of the mandrel 9, it is also possible that, on the external contour of the expanded region, a minimal place 17 forms so that the expanded area has a camel-hump-like structure.

(9) Such an expander element 7 is used in a core shooter for producing a riser body 2. FIG. 3 shows the use of a similar expander element 7 with core boxes (not shown) of a core shooter. The core boxes each have a partial cavity, which, in a merged state, form a cavity with an inner wall 18, wherein this inner wall 18 specifies the outer contour of the riser body 2 to be produced. In order to produce the riser body 2, an exothermic and/or insulating riser material is shot between the inner wall 18 of the cavity formed by the core boxes and the outer contour of the expanded expander element 7. In FIG. 3, a correspondingly expanded expander element 7 with a shot-in riser body 2 is shown, wherein the core boxes, which specify the outer contour of the riser body 2 are not shown.

(10) In FIG. 4, a riser sleeve 1 is shown, which comprises the riser body 2 and an ME sheet 16. The riser body 2 comprises a riser cavity 3 and a riser opening 4, by which the riser cavity 3 is connected to a mould cavity (not shown) of a casting mould during the casting process. The riser opening 4 defines an axis 5, wherein it is clearly visible that the diameter of the riser cavity 3 is greater than the diameter of the riser opening 4. Such riser sleeve 1 is used in the case of vertically divided casting moulds in particular where the riser sleeve 1 is horizontally aligned with its axis during the casting process. During the casting process, the riser sleeve 1 lies in a resting position.

(11) Since the volume of the riser cavity 3 is greater above the axis 5 than below the axis 5, during the casting process, a sufficiently high hydrostatic pressure is available due to the liquid metal in order to ensure feeding. The Williams element 6 formed on the peripheral surface of the riser cavity 3 serves as a hotspot for the liquid metal.

(12) With the present invention, an asymmetrical riser body comprising a riser cavity can be produced as a single piece in just one production process so that the effort for producing such a riser body is considerably simplified.

REFERENCE LIST

(13) 1 riser sleeve 2 riser body 3 riser cavity 4 riser opening 5 axis 6 Williams element 7 expander element 8 longitudinal axis 9 mandrel 10 membrane 11 intermediate space 12 peripheral edge 13 side wall 14 base 15 free end 16 sheet 17 minimal place 18 inner wall