Improved method for the crystallizer cover of an electron beam cold hearth smelting furnace

Abstract

The application relates to an improved method for the crystallizer cover plate of an electron beam cold bed smelting furnace, which measures the length of the crystallizer (without an overflow port), the thickness of the cover plate, selects a titanium plate with the same length as the crystallizer, the same thickness as the cover plate and a suitable width, and replaces part of the steel cover plate. In order to solve the connection problem between the titanium plate and the steel cover plate, a plurality of small-sized titanium plates are first bolted to the cover plate, and then the plurality of small-sized titanium plates are welded to the titanium plate replacing part of the steel cover plate, so that a part-titanium cover plate is formed. The application is simple to operate, easy to realize, and can solve the problem that hot spots hit the cover plate during the edge scanning process, so that the molten steel flows into the crystallizer.

Description

Technical Field

[0001] The present invention relates to the technical field of EB furnace crystallizer cover plate, and provides an improvement method for EB furnace crystallizer cover plate Background Art

[0002] Electron beam cold hearth melting furnace (EB furnace) uses electron beam generated by hot cathode to bombard the material, generating heat to melt the material. When using EB furnace to melt titanium and titanium alloy, the temperature of the melting chamber is high. To ensure stable melting, the roughing zone, refining zone and crystallizer are equipped with corresponding water cooling system. To protect the water cooling system, the roughing zone, refining zone and crystallization zone are equipped with appropriate steel cover. The steel cover of the crystallizer can cover the surface of the crystallizer to prevent the electron beam from hitting the crystallizer surface due to deviation and causing damage to the crystallizer. Figure 1 Schematic diagram of the currently used crystallizer steel cover.

[0003] The EB furnace of the American RETECH company has four electron guns. The 4# electron gun mainly has 6 scanning patterns, which are responsible for scanning the crystallizer area. There are two dot-shaped patterns. One is on the far left of the crystallizer to ensure that the titanium liquid at the overflow port of the crystallizer flows steadily into the crystallizer, which is called the overflow point. The other is on the far right of the crystallizer to prevent the edge of the ingot from cooling too quickly, resulting in cracking, which is called a hot spot. The remaining 4 patterns ensure the fluidity of the titanium liquid in the crystallizer. In the process of melting and casting titanium and titanium alloys, volatile titanium liquid will solidify on the two edges of the length direction of the crystallizer to form a thick film. In order to ensure the smooth progress of the melting and casting process, hot spots will be used to sweep the edges during the actual operation, so that the thick film melts and falls into the crystallizer. In the process of sweeping the edges, in order to make the thick film fully melt and fall into the crystallizer, the hot spots will often hit the steel cover plate, causing the edge of the steel cover plate to melt and the steel liquid to flow into the crystallizer, causing the Fe content in the local area of ​​the ingot to exceed the standard (standard number: GB / T3620.1-2007), resulting in quality problems of the ingot and subsequent processed products. Figure 2 In order to solve the problem of surface cracks on the ingot caused by excessively high Fe content in the ingot, an improvement method for the crystallizer cover of an electron beam cooling hearth melting furnace is invented. Summary of the Invention

[0004] The purpose of the present invention is to solve the above problems and provide a method for improving the cover plate of the crystallizer of the electron beam cooling hearth melting furnace. The present invention solves the problem of molten steel flowing into the crystallizer by partially using titanium on the cover plate. The steps are as follows:

[0005] 1) Measure the length of the crystallizer, select a titanium plate of appropriate length according to the length of the crystallizer, measure the thickness of the cover plate, and select a titanium plate of the same thickness. The width of the titanium plate should not be less than 20 mm;

[0006] 2) Select the titanium plate specifications according to step 1, and cut off the cover plate of the same specifications from the longitudinal edge of the steel cover plate by flame cutting or other cutting methods;

[0007] 3) According to the specifications of the selected bolts, use an electric drill or other drilling methods to drill holes slightly larger than the outer diameter of the bolts at appropriate locations on the cover (the holes should be 50mm to 100mm away from the edge of the cover in the vertical direction, including the length of the cut when measuring). The number of holes is not limited, and 2 to 3 holes should be symmetrical or evenly distributed in a straight line.

[0008] 4) According to the position of the hole in step 3, select a titanium plate of appropriate length. The width of the titanium plate should be larger than the hole diameter in step 3 and the thickness should be greater than 3mm. Use an electric drill or other punching method to drill a hole with the same diameter as in step 3 on the top of the titanium plate. The hole cannot exceed the edge of the titanium plate.

[0009] 5) Bolt the titanium plate and steel cover plate in step 4 together;

[0010] 6) The titanium plate in step 1 is fitted with the steel cover plate, and then fully welded to the edge of the titanium plate in step 3. The welding material grade is consistent with the titanium plate material grade.

[0011] The beneficial effect of the present invention is that, by measuring the length of the crystallizer (excluding the overflow port) and the thickness of the cover plate, the present invention selects a titanium plate with the same length and thickness as the crystallizer and an appropriate width to replace part of the steel cover plate. To solve the connection problem between the titanium plate and the steel cover plate, several small-sized titanium plates are first connected to the cover plate by bolts, and then several small-sized titanium plates are connected to the titanium plate that replaces part of the steel cover plate by welding, thereby forming a partially titanium-made crystallizer. The present invention is simple to operate, easy to implement, and can solve the problem of hot spots hitting the cover plate during the edge sweeping process, causing molten steel to flow into the crystallizer.

[0012] The present invention will be further explained and illustrated below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Schematic diagram of the steel cover plate in the prior art.

[0014] Figure 2 The ingot cracks are caused by excessive Fe content.

[0015] Figure 3 Schematic diagram of a partially used titanium cover plate in an improved embodiment of the present invention. DETAILED DESCRIPTION

[0016] The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0017] See attached Figure 3 , a schematic diagram of a titanium cover plate for local improvement.

[0018] Example:

[0019] A method for improving the cover plate of an electron beam cooling hearth melting furnace crystallizer. The invention is characterized in that the problem of molten steel flowing into the crystallizer from the cover plate is solved by partially using titanium on the cover plate. The steps are as follows:

[0020] 1) Measure the crystallizer length of 1250mm, the crystallizer overflow port of 300mm, and the cover plate thickness of 5mm. Select two TA1 titanium plates with a thickness of 5mm, a length of 1250mm, and a width of 20mm;

[0021] 2) Starting from the leftmost 300mm of the cover, use flame cutting to remove a section with a length of 1250mm and a width of 20mm;

[0022] 3) Use M8 bolts and nuts, and drill three 9mm diameter holes every 400mm within a length of 1250mm, starting from 300mm from the leftmost point of the cover, 80mm away from the vertical edge of the cover;

[0023] 4) Select 6 pieces of TA1 plates with a length of 100 mm, a width of 12 mm, and a thickness of 3 mm, and drill a 9 mm diameter hole 12 mm from the top of the plate.

[0024] 5) Connect the six TA1 titanium plates from step 4 to the cover plate using M8 bolts;

[0025] 6) The two titanium plates in step 1 are interlocked with the steel cover plate, and argon arc welding is used to weld the edges of the titanium plates in step 3 with TA1 welding wire with a diameter of 1 mm.

[0026] The above are only some specific embodiments of the present invention (since the present invention includes a numerical range, the embodiments cannot be exhaustive, and the protection scope recorded in the present invention includes the numerical range and other technical key points of the present invention). The specific content or common sense known in the scheme is not described in detail here (including but not limited to abbreviations, abbreviations, and units commonly used in this field). It should be pointed out that the above embodiments do not limit the present invention in any way. For those skilled in the art, all technical solutions obtained by equivalent replacement or equivalent transformation fall within the protection scope of the present invention. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for improving the cover plate of the crystallizer of an electron beam cooling hearth melting furnace, characterized in that: The improved method comprises the following steps: 1) Measure the length of the crystallizer, select the appropriate length of titanium plate according to the length of the crystallizer, measure the thickness of the cover plate, and select the matching titanium plate; 2) Select the titanium plate specifications according to step 1, and cut off the same specifications of the steel cover plate by flame cutting or other cutting methods along the length direction of the steel cover plate; 3) According to the specifications of the selected bolts, use an electric drill or other drilling methods to drill holes with a diameter slightly larger than the outer diameter of the bolts at appropriate locations on the cover plate. The number of holes is not limited; 4) Select a titanium plate of appropriate length based on the position of the hole in step 3; drill a hole of the same diameter as in step 3 on the top of the plate using an electric drill or other drilling method; 5) Bolt the titanium plate and steel cover plate in step 4 together; 6) The titanium plate in step 1 is interlocked with the steel cover plate, and then the edges are fully welded with the titanium plate in step 3; completed.

2. The method according to claim 1, wherein The width of the titanium plate in step 1 is not less than 20 mm.

3. The method according to claim 1, wherein The number of holes in step 3 is 2 to 3, which are symmetrically arranged or evenly distributed in a straight line.

4. The method according to claim 1, wherein The width of the titanium plate in step 3 is greater than the aperture in step 3.

5. The method according to claim 1, wherein The thickness of the titanium plate in step 4 is greater than 3 mm.

6. The method according to claim 1, wherein The hole in step 4 cannot exceed the edge of the titanium plate.

7. The method according to claim 1, wherein The grade of the welding material in step 6 is consistent with the grade of the titanium plate material.

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