Abstract
An isostatically pressed product (10, 11, 12, 13, 14) for use in handling of molten metals comprising: a body (20) made from a first refractory composition (50); the body (20) comprises a surface (21); and at least one liner section (30.1) applied partially onto the surface (21) of the body (20); the at least one liner section (30.1) is made from a second refractory composition (51); the at least one liner section (30.1, 30.2) forming the liner (30) of the body (20); whereas in at least one cross-section of the product, the surface (21) of the body (20) in a region covered with the liner (30), comprises at least one convex (41) and at least two concave (42) sections and a method for manufacturing an isostatically pressed product (10, 11, 12, 13, 14) for use in handling of molten metals.
Claims
1. An isostatically pressed product (10, 11, 12, 13, 14) for use in handling of molten metals comprising: 1.1 a body (20) made from a first refractory composition (50); 1.2 the body (20) comprises a surface (21); 1.3 and at least one liner section (30.1) applied partially onto the surface (21) of the body (20); the at least one liner section (30.1) is made from a second refractory composition (51); 1.4 the at least one liner section (30.1, 30.2) forming a liner (30) of the body (20); 1.5 whereas in at least one cross-section of the product (10, 11, 12, 13, 14), the surface (21) of the body (20) in a region covered with the liner (30) comprises at least one convex (41) and at least two concave (42) sections; 1.6 whereas the product (10, 11, 12, 13, 14) is an isostatically pressed product.
2. Isostatically pressed product (10, 11, 12, 13, 14) according to claim 1, characterized in that the at least one liner section (30.1, 30.2) is of cylindrical symmetry.
3. Isostatically pressed product (10, 11, 12, 13, 14) according to claim 1, characterized in that the isostatically pressed product (10, 11, 12, 13, 14) for use in handling of molten metals is of cylindrical symmetry.
4. Isostatically pressed product (10, 11, 12, 13, 14) according to claim 1, characterized in that the at least one liner section (30.1, 30.2) has the form of a toroid.
5. Isostatically pressed product (10, 11, 12, 13, 14) according to claim 2, characterized in that in a half-section of the isostatically pressed product (10, 11, 12, 13, 14) through an axis of symmetry of the product, an intersection of the half-section and the surface (21) of the body (20) in a region covered with the liner (30), comprises at the least one convex (41) and at least two concave (42) sections.
6. Isostatically pressed product (10, 11, 12, 13, 14) according to claim 1, characterized in that the isostatically pressed product (10, 11, 12, 13, 14) for use in handling of molten metals is selected from the group of: a stopper rod (11), a refractory nozzle, a submerged entry shroud (13), or a ladle shroud (14).
7. Isostatically pressed product (10, 11, 12, 13, 14) according to claim 1, characterized in that in the at least one cross-section or in at least one half-section of the isostatically pressed product (10, 11, 12, 13, 14), the surface (21) of the body (20) in a region covered with the liner (30), comprises at least two convex or at least three concave sections.
8. Isostatically pressed product (10, 11, 12, 13, 14) according to claim 1, characterized in that refractory compositions (50, 51) of the body (20) and the at least one liner section (30.1, 30.2) forming the liner (30) of the body (20) form a jointless connection.
9. Method for manufacturing a product (10, 11, 12, 13, 14) for use in handling of molten metals, the product comprising a body (20) with a surface (21) and at least one liner (30) applied at least partially onto the surface (21) of the body (20), the method comprises the following steps: 9.1 placing a first division wall (110) into a mold (100), such that a lower end of the first division wall (110) is positioned at a first height (h1) above a bottom surface (102) of the mold (100); 9.2 filling a first refractory composition (50) on a first side of the first division wall (110) into the mold (100); 9.3 filling a second refractory composition (51) on a second side of the first division wall (110) into the mold (100); 9.4 removing the first division wall (110) from the mold (100); and 9.5 pressing the refractory compositions (50, 51).
10. Method according to claim 9, characterized in that the mold is an isostatic pressing mold and pressing is affected by an isostatic pressing apparatus.
11. Method according to claim 17, characterized in that a third division wall (112) is placed into the mold (100), such that a lower end of the third division (112) wall is positioned at a third height (h3) above the bottom surface (102) of the mold (100).
12. Method according to claim 17, characterized in that the first division wall (110) and the second division wall (111) are concentrically arranged cylindrical shells and the mold (100) comprises a cylindrical sidewall (101).
13. Method according to claim 17, characterized in that the first division wall (110) and the second division wall (111) are of cylindrical symmetry and share a symmetry axis.
14. Method according to claim 11, characterized in that the first division wall (110) is encircled by the second division wall (111), the second division wall (111) is encircled by the third division wall (112); and whereas the second height (h2) of the second division wall (111) lies between the first height (h1) of the first division wall (110) and the third height (h3) of the third division wall (112) above the bottom surface (102) of the mold (100).
15. Product for use in handling molten metals, the product obtained by performance of a process, the process comprising: placing a first division wall (110) into a mold (100), such that a lower end of the first division wall (110) is positioned at a first height (h1) above a bottom surface (102) of the mold (100); filling a first refractory composition (50) on a first side of the first division wall (110) into the mold (100); filling a second refractory composition (51) on a second side of the first division wall (110) into the mold (100); removing the first division wall (110) from the mold (100); and pressing the refractory compositions (50, 51).
16. The isostatically pressed product (10, 11, 12, 13, 14) of claim 1, wherein the body (20) and the at least one liner section (30.1) are isostatically pressed in a single step.
17. Method according to claim 9, further comprising: placing a second division wall (111) into the mold (100), such that a lower end of the second division wall (111) is positioned at a second height (h2) above the bottom surface (102) of the mold (100).
18. Method according to claim 17, further comprising: filling the second refractory composition (51) or a third refractory composition (52) on a second side of the second division wall (111) into the mold.
19. Product according to claim 15, the process further comprising: placing a second division wall (111) into the mold (100), such that a lower end of the second division wall (111) is positioned at a second height (h2) above the bottom surface (102) of the mold (100).
20. Product according to claim 19, the process further comprising: filling the second refractory composition (51) or a third refractory composition (52) on a second side of the second division wall (111) into the mold (100).
Description
[0074] Exemplary embodiments of the invention are explained in more detail by means of illustrations:
[0075] FIG. 1 shows a schematic setup during production of a first isostatically pressed product for handling molten metal, such as a stopper rod.
[0076] FIG. 2 shows a schematic cross-section of a first isostatically pressed product for handling molten metal, such as a stopper rod.
[0077] FIG. 3 shows a schematic setup during production of a second isostatically pressed product for handling molten metal, such as a stopper rod.
[0078] FIG. 4 shows a schematic cross-section of a second isostatically pressed product for handling molten metal, such as a stopper rod.
[0079] FIG. 5 shows a schematic setup during production of a third isostatically pressed product for handling molten metal, such as a submerged entry nozzle, or a submerged entry shroud, or a ladle shroud.
[0080] FIG. 6 shows a schematic cross-section of a third isostatically pressed product for handling molten metal, such as a submerged entry nozzle, or a submerged entry shroud, or a ladle shroud.
[0081] FIG. 7 shows a schematic setup during production of a third isostatically pressed product for handling molten metal, such as a submerged entry nozzle, or a submerged entry shroud, or a ladle shroud.
[0082] FIG. 8 shows a schematic cross-section of a third isostatically pressed product for handling molten metal, such as a submerged entry nozzle, or a submerged entry shroud, or a ladle shroud.
[0083] FIG. 9 shows a picture of a test bar produced according to the invention.
[0084] FIG. 1 shows a schematic setup during production of a first isostatically pressed product for handling molten metal, such as a stopper rod (11). A mold (100) comprising a cylindrical sidewall (101), and a bottom surface (102), and optionally an inside form (103) of the shape of a mandrel is provided. A first division wall (110) and a second division wall (111) are placed into the mold (100) in a position above the bottom surface (102) of the mold (100). The lower end of the first division wall (110) is positioned at a first height (h1) above the bottom surface (102) of the mold (100) and the lower end of the second division wall (111) is positioned at a second height (h2) above the bottom surface (102) of the mold (100). Here the first division wall (110) is encircled by the second division wall (111), h2<h1, as h1=98 cm and h2 is 97 cm. The first (110) and second (111) division walls are concentrically arranged shells with respective diameters of 7 cm and 9 cm. Their axis coincides with the axis of the cylindrical sidewall (101) of the mold (the axis is shown by the vertical dot shaped line in FIG. 1), the cylindrical sidewall (101) of the mold (100) has a diameter of 13 cm. A first refractory composition (50) with a first chemical composition is filled into the mold through the first division wall (110), that is through/near its axis. The refractory composition (50) flows into the mold (100) and is constrained within the sidewall (101) of the mold (100). Optionally, an inside form (103) can be present in the lower part of the mold (100). Inside the sidewall (101) the first refractory composition (50) builds a cone with a repose angle/angle of repose, which is the steepest angle at which a sloping surface formed of loose material is stable. This angle is shown in FIG. 1 for different filling heights (see doted sloped lines). When the cone reaches a certain height, the first refractory composition (50) is constrained within the second division wall (111). Now this constrained cone builds up inside the second division wall (111) until at a certain height where the first refractory composition (50) is constrained within the first division wall (110), where it can be filled up to the top. Then a second refractory composition (51) with a second chemical composition is filled on a second side of the first division wall (110), that is into the (free/unfilled) space formed between the first (110) and second (111) division wall. The same second refractory composition (51) with a second chemical composition is filled on a second side of the second division wall (111), that is into the (free/unfilled) space formed between the second division wall (111) and the sidewall (101) of the mold (100). Subsequently, the first (110) and second (111) division walls are removed by pulling the walls (110, 111) vertically out of the refractory compositions (50, 51). The refractory compositions (50, 51) fill the (thin) voids where the walls (110, 111) have been before. The mold is then closed on the top and the refractory compositions (50, 51) are isostatic pressed. FIG. 2 shows a cross-section of an isostatically pressed product (10, 11) obtained by this production of a first isostatically pressed product. It shows a stopper head of a stopper rod (11), with a cylindrical body (20) made from a first refractory composition (50) and a cylindrical liner (30) (in the form of a toroid) with a first (cylindrical) liner section (30.1) made from a second refractory composition (51). The liner section (30.1), forming the liner (30), is applied partially onto the surface (21) of the body (20). The region where the liner (30) covers the surface (21) of the body (20) defines an interface region. The cross-section through the cylindrical axis (vertical dot-dashed line) of FIG. 2 shows that the surface (21) of the body (20) in the region covered with the liner (30) has one convex (41) and two concave (42) sections as seen from the body (20). These sections for interlocking the body and the liner can be formed by curved intersections (as shown in the figure) or alternatively as sections with steps (40) (not shown in the figures). The part of FIG. 2 on the right side of the cylindrical axis (that is the vertical dot-dashed line) represents a half-section of the isostatically pressed product (10, 11) through its cylindrical axis, the intersection of the half-section and the surface (21) of the body (20) in a region covered with the liner (30), has one convex (41) and two concave (42) sections as seen from the body (20). The part of FIG. 2 on the left side of the cylindrical axis (that is the vertical dot-dashed line) represents a front view of the isostatically pressed product (10,11), with the (outer) surface of the body (21) and a liner (30). The outer surface of the liner (30) achieved a liner section that covers 50% of the total surface of the stopper nose geometry and has a maximum thickness of 10 mm.
[0085] FIG. 3 shows a schematic setup during isostatically pressed production of a second isostatically pressed product for handling molten metals, such as a stopper rod (11). The setup is similar as already discussed for FIG. 1 with the exception, that an additional third division wall (112) is placed into the mold (100) in a position above the bottom surface (102) of the mold (100). The lower end of the third division wall (112) is positioned at a third height (h3) above the bottom surface (102) of the mold (100). Here the first division wall (110) is encircled by the second division wall (111), which is encircled by the third division wall (112), h3<h2<h1, as h1=98 cm, h2=97 cm and h3=95 cm. The first (110), second (111) and third (112) division walls are concentrically arranged shells. Their axis coincides with the axis of the cylindrical sidewall (101) of the mold (the axis is shown by the vertical dot shaped line in FIG. 3). Filling of the first refractory composition (50) is similar as already described for the first isostatically pressed product (FIG. 2). Further, in one example, the first refractory composition (50) and the second refractory composition (51) have the same chemical composition but have a different porosity. The second refractory composition (51) is filled on a second side of the first division wall (110), that is into the space formed between the first (110) and second (111) division wall. The same second refractory composition (51) is filled on a second side of the second division wall (111), that is into the space formed between the second division wall (111) and the third division wall (112). The same second refractory composition (51) is filled on a second side of the third division wall (112), that is into the space formed between the third division wall (112) and the sidewall (101) of the mold (100). Removal of the division walls and further pressing is performed as described with the first isostatically pressed product. The cross-section through the cylindrical axis (vertical dot-dashed line) of the obtained isostatically pressed product in FIG. 4 shows that the surface (21) of the body (20) in the region covered with the liner (30) has two convex (41) and three concave (42) sections, as seen from the body. These sections for interlocking the body and the liner can be formed by curved intersections (as shown in the figure) or alternatively as sections with steps (40) (not shown in the figures). The part of FIG. 4 on one side of the cylindrical axis (that is the vertical dot-dashed line) represents a half-section of the isostatically pressed product (10, 11) through its cylindrical axis, the intersection of the half-section and the surface (21) of the body (20) in a region covered with the liner (30), has two convex (41) and three concave (42) sections, as seen from the body. The outer surface of the liner achieved a liner section that covers 75% of the total surface of the stopper nose geometry and has a maximum thickness of 1 cm.
[0086] In an alternative example of the one discussed in connection with FIG. 3 (not separately shown in the figures), instead of the second compositions (51), a third refractory composition (52) with a different chemical composition is filled on a second side of the second division wall (111). Therefore the resulting liner (30) consists of three liner sections (30.1, 30.2, 30.3), whereas the first (30.1) and third (30.3) liner sections are made from the second refractory composition (51), whereas the second liner section (30.2) is made from the third refractory composition (52).
[0087] FIG. 5 shows a schematic setup during production of a third isostatically pressed product for handling molten metals, such as a ladle shroud (14). A mold (100) with a cylindrical sidewall (101) and an inside form (103) of the shape of a mandrel is provided and a bottom surface (102). A first division wall (110) and a second division wall (111) are placed into the mold (100) in a position above the bottom surface (102) of the mold (100). The lower end of the first division wall (110) is positioned at a first height (h1) above the bottom surface (102) of the mold (100) and the lower end of the second division wall (111) is positioned at a second height (h2) above the bottom surface (102) of the mold (100). Here the second division wall (111) is encircled by the first division wall (110), h1>h2, as h1=99 cm and h2 is 98 cm. The first (110) and second (11) division walls are concentrically arranged shells with respective diameters of 9 cm and 7 cm. Their axis coincides with the axis of the cylindrical sidewall (101) of the mold (the axis is shown by the vertical dot shaped line in FIG. 5), the cylindrical sidewall (101) of the mold (100) has a diameter of 13 cm. A first refractory composition (50) with a first carbon content is filled into the mold (uniformly) along the inside of the cylindrical sidewall (101) (and outside of the first division wall (110)), that is through/near its periphery. The refractory composition (50) flows into the mold (100) and is constrained within the sidewall (101) and the inside form (103) of the mold (100). Inside the sidewall (101) the first refractory composition (50) builds a negative cone with a repose angle/angle of repose, which is the steepest angle at which a sloping surface formed of loose material is stable. This angle is shown in FIG. 5 for different filling heights (see doted sloped lines). When the negative cone reaches a certain height, the first refractory composition (50) is constrained within the second division wall (111). Now this constrained negative cone builds up outside the second division wall (111), until at a certain height, after which the first refractory composition (50) is constrained within the first division wall (110), where it can be filled up to the top outside the first division wall (110). Then a second refractory composition (51) with lower carbon content is filled on a second side of the first division wall (110), that is into the space formed between the first division wall (110) and the second division wall (111). The same second refractory composition (51) with a lower carbon content is filled on a second side of the second division wall (111), that is into the space formed between the second division wall (111) and the inside form (103). Subsequently, the first (110) and second (111) division walls are removed by pulling the walls (110, 111) vertically out of the refractory compositions (50, 51). The refractory compositions (50, 51) fill the (thin) voids where the walls (110, 111) have been before. The mold is then closed on the top and the refractory compositions (50, 51) were isostatic pressed. FIG. 6 shows a cross-section of a isostatically pressed product (10, 14) obtained by this production of a third isostatically pressed product. It shows a nozzle of a ladle shroud (14), with a cylindrical body (20) made from a first refractory composition (50) and a cylindrical liner (30) (in the form of a toroid) with a first (cylindrical) liner section (30.1) made from a second refractory composition (51). The liner section (30.1), forming the liner (30), is applied partially onto the inner surface (21) of the body (20). In the region where the liner (30) covers the surface (21) of the body (20) defines in interface region. The cross-section through the cylindrical axis (vertical dot-dashed line) of FIG. 6 shows that the surface (21) of the body (20) in the region covered with the liner (30) has one convex (41) and two concave (42) sections. These sections for interlocking the body and the liner can be formed by curved intersections (as shown in the figure) or alternatively as sections with steps (40) (not shown in the figures). The part of FIG. 6 on one side of the cylindrical axis (that is the vertical dot-dashed line) represents a half-section of the isostatically pressed product (10, 14) through its cylindrical axis, the intersection of the half-section and the surface (21) of the body (20) in a region covered with the liner (30), has one convex (41) and two concave (42) sections. The outer surface of the liner achieved a liner section that covers 50% of the total surface of the seat area of the nozzle and has a maximum thickness of 1 cm.
[0088] FIG. 7 shows a schematic setup during production of a fourth isostatically pressed product for handling molten metals, such as a ladle shroud (14). The setup is similar as already discussed for FIG. 5 with the exception, that an additional third division wall (112) is placed into the mold (100) in a position above the bottom surface (102) of the mold (100). The lower end of the third division wall (112) is positioned at a third height (h3) above the bottom surface (102) of the mold (100). Here the third division wall (112) is encircled by the second division wall (111), which is encircled by the first division wall (110), h1>h2>h3, as h1=98 cm, h2=97 cm and h3=95 cm. The first (110), second (111) and third (112) division walls are concentrically arranged shells. Their axis coincides with the axis of the cylindrical sidewall (101) of the mold (the axis is shown by the vertical dot shaped line in FIG. 7). Filling of the first refractory composition (50) is similar as already described for the third isostatically pressed product (FIG. 5). Further, in one example, a second refractory composition (51) with a different density is filled on a second side of the first division wall (110), that is into the space formed between the first division wall (110) and the second division wall (111). The same second refractory composition (51) with a different density is filled on a second side of the second division wall (111), that is into the space formed between the second division wall (111) and the third division wall (112). The same second refractory composition (51) with a different density is filled on a second side of the third division wall (112), that is into the space formed between the third division wall (112) and the inside form (103). Removal of the division walls and further pressing is performed as described with the third isostatically pressed product. The cross-section through the cylindrical axis (vertical dot-dashed line) of the obtained isostatically pressed product in FIG. 8 shows that the surface (21) of the body (20) in the region covered with the liner (30) has two convex (41) and three concave (42) sections. These sections for interlocking the body and the liner can be formed by curved intersections (as shown in the figure) or alternatively as sections with steps (40) (not shown in the figures). The part of FIG. 8 on one side of the cylindrical axis (that is the vertical dot-dashed line) represents a half-section of the isostatically pressed product (10, 14) through its cylindrical axis, the intersection of the half-section and the surface (21) of the body (20) in a region covered with the liner (30), has two convex (41) and three concave (42) sections.
[0089] In an alternative example of the one discussed in connection with FIG. 7 (not separately shown in the figures), instead of the second compositions (51), a third refractory composition (52) with different chemical composition is filled on a second side of the second division wall (111). Therefore the resulting liner (30) consists of three liner sections (30.1, 30.2, 30.3), whereas the first (30.1) and third (30.3) liner sections are made from the second refractory composition (51), whereas the second liner section (30.2) is made from the third refractory composition (52).
[0090] FIG. 9 shows an image of a test bar produced with the method according to the invention. Such test bars were produced to evaluate the bending strength, including the strength of the interface. The test bar shown in FIG. 9 was made from a first refractory material and a second refractory material. Similar test bars were manufactured from solely the first refractory material, and solely the second refractory material. The test bars made from only one material showed a bending strength of 5.83 MPa and 7.83 MPa respectively. The test bar from FIG. 9 achieved a bending strength of 6.75 Mpa, which is in the middle of the two pure materials. This shows that the interface indeed shows very good mechanical properties, and the two refractory materials show very good adhesion to each other.
LIST OF REFERENCE NUMERALS AND FACTORS (GERMAN TRANSLATION IN PARENTHESIS)
[0091] 10 Isostatically pressed product for use in handling of molten metals [0092] 11 Stopper rod [0093] 12 Submerged entry nozzle [0094] 13 Submerged entry shroud [0095] 14 Ladle shroud [0096] 20 Body [0097] 21 Surface of the body [0098] 30 Liner [0099] 30.1 First liner section [0100] 30.2 Second liner section [0101] 30.3 Third liner section [0102] 31 Outer surface of liner (30) [0103] 40 Step [0104] 41 Convex section [0105] 42 Concave section [0106] 50 First refractory composition [0107] 51 Second refractory composition [0108] 52 Third refractory composition [0109] 100 Mold [0110] 101 Sidewall of mold [0111] 102 Bottom surface of mold [0112] 103 Inside form of mold [0113] 110 First division wall [0114] 111 Second division wall [0115] 112 Third division wall [0116] h1 First height of first division wall (110) above the bottom surface (102) of the mold (100) [0117] h2 Second height of second division wall (111) above the bottom surface (102) of the mold (100) [0118] h3 Third height of third division wall (112) above the bottom surface (102) of the mold (100)
