Spiral-orifice ceramic filter for metal casting

Abstract

A spiral-orifice ceramic filter for metal casting, including spiral channels and two drain openings, where the spiral channels are distributed in a ceramic substrate in a staggered manner. By adoption of the spiral channel structure, molten metal may rotate to generate a centrifugal force while flowing forwards so as to promote separation of inclusions. The spiral-orifice ceramic filter for metal casting includes the following components: 90-95 wt % of MgO, 4-8 wt % of SiO.sub.2 and 2-4 wt % of ZrO.sub.2. Therefore, the spiral-orifice ceramic filter for metal casting has high strength under normal temperature and optional thermal impact resistance under high temperature, and may tolerate the impact of molten metal at 1700° C. or higher without break. The ceramic substrate and the spiral channel are superficially coated with one layer of functional oxide prepared from CaO.2Al.sub.2O.sub.3, CaO.6Al.sub.2O.sub.3, Al.sub.2O.sub.3, TiO.sub.2, or Re.sub.2O.sub.3.

Claims

1. A spiral-orifice ceramic filter for metal casting, comprising: a ceramic filter substrate that includes spiral filter channels arranged in rows such that adjacent rows are distributed in a staggered manner, each spiral filter channel having a vertical section that is round, and wherein two drain openings are formed at a bottom of the ceramic filter substrate, wherein the ceramic filter substrate and the spiral filter channels are coated with an oxide layer with a composition of one of CaO.2Al.sub.2O.sub.3, CaO.6Al.sub.2O.sub.3, Al.sub.2O.sub.3, TiO.sub.2, or Re.sub.2O.sub.3, and wherein the spiral-orifice ceramic filter comprises 90-95 wt % of MgO, 4-8 wt % of SiO.sub.2, and 2-4 wt % of ZrO.sub.2.

2. The spiral-orifice ceramic filter of claim 1, wherein a diameter of each spiral filter channel is ¼ to ⅓ a thickness of the ceramic filter.

3. The spiral-orifice ceramic filter of claim 1, wherein in each row, a horizontal distance between adjacent spiral channels is 2 to 3 times a diameter of a spiral line that forms each respective spiral channel.

4. The spiral-orifice ceramic filter of claim 1, wherein a vertical distance between the adjacent rows of the spiral filter channels is 2.5 to 3.5 times a diameter of a spiral line that forms each respective spiral filter channel.

5. The spiral-orifice ceramic filter of claim 1, wherein spiral line that forms each respective spiral filter channel has no more than three spiral coils.

6. The spiral-orifice ceramic filter of claim 1, wherein a diameter of a spiral line that forms each respective spiral filter channel is 1.5 to 2.5 times that of the spiral filter channel.

7. The spiral-orifice ceramic filter of claim 1, wherein a thickness of each spiral filter channel is in a range of 60-120 mm according to external dimensions of the spiral filter channel.

8. The spiral-orifice ceramic filter of claim 1, wherein the ceramic filter substrate is shaped like a flat plate.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic structural diagram of a spiral-orifice ceramic filter for metal casting according to the present invention;

(2) FIG. 2 is a schematic diagram of a spiral channel;

(3) FIG. 3 is a side view of a spiral channel; and

(4) FIG. 4 is a front view of a spiral-orifice ceramic filter.

(5) In the figures, reference numeral 1 is a spiral channel, reference numeral 2 is a drain opening; reference symbol a is a diameter of a round channel, reference symbol b is a gap between two spiral lines, reference symbol c is a diameter of the spiral line, reference symbol d is a horizontal distance between two spiral channels, and reference symbol e is a vertical distance between upper and lower rows of spiral channels.

DETAILED DESCRIPTION

(6) The present invention will be further described with reference to the accompanying drawings and the examples.

(7) As shown in FIG. 1, a structure of the spiral-orifice ceramic filter for metal casting according to the present invention includes a spiral channel 1 and a drain opening 2. A schematic diagram of the spiral channel is shown in FIG. 2.

Example 1

(8) The spiral-orifice ceramic filter according to the example has chemical components including 92 wt % of MgO, 5 wt % of SiO.sub.2 and 3 wt % of ZrO.sub.2, and a thickness of 80 mm.

(9) A structure of the spiral channel is shown in FIG. 3, a diameter a of a round channel is 25 mm, there are two spiral coils, a gap b between two spiral lines is 40 mm, and a diameter c of the spiral line is 37.5 mm.

(10) Distribution of the spiral channels on the ceramic substrate is shown in FIG. 4, a horizontal distance d between two spiral channels is 75 mm, a vertical distance e between upper and lower rows of spiral channels is 95 mm, and the upper and lower rows of spiral channels are distributed in a staggered manner.

(11) The ceramic substrate and the spiral channel of the spiral-orifice ceramic filter for metal casting are superficially coated with one layer of CaO.2Al.sub.2O.sub.3.

(12) The spiral-orifice ceramic filter for metal casting is not damaged after being subjected to a filter test of 1000 kg of carbon steel liquid at high temperature of 1550° C. by a 500 mm casting pressure head. Through analysis of components and a microstructure of a steel ingot before and after casting, the content of the inclusions is reduced by about 65%.

Example 2

(13) The spiral-orifice ceramic filter according to the example has chemical components including 90 wt % of MgO, 6 wt % of SiO.sub.2 and 4 wt % of ZrO.sub.2, and a thickness of 100 mm.

(14) According to the spiral-orifice ceramic filter, a diameter a of a round channel is 30 mm, there are two spiral coils, a gap b between two spiral lines is 50 mm, and a diameter c of the spiral line is 45 mm.

(15) A horizontal distance d between two spiral channels is 90 mm, a vertical distance e between upper and lower rows of spiral channels is 115 mm, and the upper and lower rows of spiral channels are distributed in a staggered manner.

(16) The ceramic substrate and the spiral channel of the spiral-orifice ceramic filter for metal casting are superficially coated with one layer of TiO.sub.2.

(17) The spiral-orifice ceramic filter for metal casting is not damaged after being subjected to a filter test of 500 kg of molten aluminum at high temperature of 950° C. by a 500 mm casting pressure head. Through analysis of components and a microstructure of an aluminum ingot before and after casting, the content of the inclusions is reduced by about 70%.