VAR smelting method for preparing high-quality titanium ingot by adopting vertical pressed electrode

Abstract

The invention provides a VAR smelting method for preparing a high-quality titanium ingot by adopting a vertical pressed electrode, and relates to the technical field of metallurgy, and the VAR smelting method comprises the following steps: step 1, taking sponge titanium or titanium alloy as an electrode material, and pressing on a vertical press to obtain a pressed electrode; secondly, the pressed electrode is installed and welded, the center rod is placed in a center hole of the pressed electrode, and a consumable electrode is obtained; and thirdly, electric arc is generated between the consumable electrode and the substrate to smelt the consumable electrode, and the high-quality titanium ingot is obtained. According to the method, the probability of inclusion in the central part in the pure titanium smelting and ingot casting process can be effectively reduced, so that the surface peeling and central stripe defects of a titanium plate coil are reduced, and help is provided for solving and treating subsequent quality problems.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a VAR smelting method for preparing high-quality titanium ingots by using vertical pressing electrodes. Background Art

[0002] VAR furnace stands for vacuum consumable arc furnace, which is one of the main equipment for melting titanium and titanium alloys in China. Compared with traditional melting process, it has the advantages of high uniformity of ingot composition, low environmental pollution and good working environment, so it has been widely used in the production of titanium and titanium alloys.

[0003] Before melting pure titanium in a VAR furnace, the raw material titanium sponge needs to be pressed into electrode blocks, and then multiple electrode blocks are welded into electrode rods. The electrode rods made by pressing electrodes with a vertical press have holes in the center. The holes will form inclusion channels, which will cause the sponge titanium with high impurity elements such as Cl and Mg to react with the relatively pure sponge titanium in the center to form inclusions in the center of the ingot.

[0004] There is no patent for the VAR smelting method of preparing high-quality titanium ingots by plugging the center hole using vertical pressing electrodes. The purpose of the present invention is to reduce the inclusions in the core of the ingot and improve the quality of the subsequent titanium coil surface. Summary of the invention

[0005] According to the above technical problem that the central hole of the electrode rod in the existing vertical pressing electrode for preparing high-quality titanium ingots forms an inclusion channel that affects the quality of the titanium coil surface, a VAR smelting method for preparing high-quality titanium ingots using vertical pressing electrodes is provided. The present invention mainly blocks the central hole, thereby effectively reducing the probability of central inclusions during pure titanium smelting and ingot casting.

[0006] The technical means adopted by the present invention are as follows:

[0007] A VAR smelting method for preparing high-quality titanium ingots by vertical pressing electrodes comprises the following steps:

[0008] Step 1: Use titanium sponge or titanium alloy as the electrode material and press it on a vertical press to obtain a pressed electrode;

[0009] Step 2: After the pressed electrode is welded, the center rod is placed into the center hole of the pressed electrode to obtain a consumable electrode;

[0010] Step 3: An arc is generated between the consumable electrode and the substrate to melt the consumable electrode and obtain a high-quality titanium ingot.

[0011] Furthermore, the diameter φ of the pressed electrode is 470-820 mm, and the inner diameter φ of the core is 80-85 mm.

[0012] Furthermore, the specification of the center rod is φ77-83 (±0.5) mm×L, where L is the actual length of the electrode; the composition of the center rod is consistent with that of the electrode, its surface is smooth and free of oxide scale, and the end is flattened.

[0013] Furthermore, the step 2 includes starting a vacuum pump to extract air from the furnace body and controlling the vacuum degree in the furnace to be ≤5Pa before welding.

[0014] Furthermore, the group welding current is 3-12 kA, the voltage is 28-36 V, and a primary welding electrode is obtained after group welding, which is taken out of the furnace for inspection after cooling for more than 45 minutes.

[0015] Furthermore, the step three specifically includes: controlling the melting speed of the consumable electrode by adjusting the current to keep the arc stable.

[0016] Furthermore, the consumable electrode is melted twice, the first melting current is 15-26 kA, the second melting current is 20-36 kA, and the arc is stabilized at a current of 9-20 A.

[0017] Furthermore, during the smelting process, the molten titanium metal drips into a crystallizer to gradually form an ingot.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The present invention can effectively reduce the probability of core inclusions during pure titanium smelting and ingot casting, thereby reducing surface peeling and core stripe defects on titanium coils, and providing assistance for solving and handling subsequent quality problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1 The figure is a flow chart of the method of the present invention.

[0022] Figure 2 The invention relates to an electrode rod for vertically pressing an electrode.

[0023] Figure 3 The center rod is chamfered according to the present invention. DETAILED DESCRIPTION

[0024] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0027] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0028] like Figure 1-3 As shown, the present invention provides a VAR smelting method for preparing high-quality titanium ingots by vertical pressing electrodes, comprising the following steps:

[0029] Step 1: Use titanium sponge or titanium alloy as the electrode material and press it on a press to obtain a pressed electrode;

[0030] Step 2: Based on step 1, after the pressed electrode is welded, the center rod is placed into the center hole of the pressed electrode to obtain a consumable electrode;

[0031] The pressed electrode diameter φ is 470-820mm, and the core inner diameter φ is 80-85mm;

[0032] The specification of the center rod is φ77-83 (±0.5) mm×L, where L is the actual length of the electrode; the composition of the center rod is consistent with that of the electrode, its surface is smooth and free of oxide scale, and the end is flattened.

[0033] Before welding, the following steps are performed: start the vacuum pump to extract the air from the furnace and control the vacuum degree in the furnace to ≤5Pa;

[0034] The welding current is 3-12kA, the voltage is 28-36V, and a primary welding electrode is obtained after welding. After cooling for more than 45 minutes, it is taken out of the furnace for inspection.

[0035] Step 3: An arc is generated between the consumable electrode and the substrate to melt the consumable electrode and obtain a high-quality titanium ingot.

[0036] The melting speed of the consumable electrode is controlled by adjusting the current to keep the arc stable.

[0037] The consumable electrode is melted twice, the first melting current is 15-26kA, the second melting current is 20-36kA, and the arc is stable at a current of 9-20A.

[0038] Ensure that the temperature of the molten pool is uniform and avoid overheating or cooling too quickly. As the electrode melts, it automatically drops to ensure that the arc length remains constant. During the smelting process, the molten titanium metal drips into the crystallizer and gradually forms an ingot.

[0039] Example 1: For pure titanium TA1 smelting. In actual production, 9 tons of TA1 were smelted with the same raw materials, smelting process and no abnormalities during the smelting process. Compared with the titanium ingots without electrode center rod smelting, the surface peeling defects of titanium plate coils were reduced by 71.43%, and the core stripe defects were reduced by 67.28%.

[0040] Example 2: For pure titanium TA1 smelting. In actual production, 3 tons of TA1 were smelted with the same raw materials, smelting process and no abnormalities during the smelting process. Compared with the titanium ingots without electrode center rod smelting, the surface peeling defects of titanium plate coils were reduced by 22.14%, and the core stripe defects were reduced by 33.51%.

[0041] Example 3: For pure titanium TA2 smelting. In actual production, 9 tons of TA2 were smelted with the same raw materials, the same smelting process and no abnormalities during the smelting process. Compared with the titanium ingots without electrode center rod smelting, the titanium plate coil surface peeling defects were reduced by 40.43%, and the center stripe defects were reduced by 26.12%.

[0042] Example 4: For pure titanium TA2 smelting. In actual production, 3 tons of TA2 were smelted with the same raw materials, smelting process and no abnormalities during the smelting process. Compared with the titanium ingots without electrode center rod smelting, the surface peeling defects of titanium plate coils were reduced by 38.26%, and the core stripe defects were reduced by 18.35%.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A VAR smelting method for preparing high-quality titanium ingots by vertical pressing electrodes, characterized in that: The following steps are involved: Step 1: Use titanium sponge or titanium alloy as the electrode material and press it on a vertical press to obtain a pressed electrode; Step 2: After the pressed electrode is welded, the center rod is placed into the center hole of the pressed electrode to obtain a consumable electrode; Step 3: An arc is generated between the consumable electrode and the substrate to melt the consumable electrode and obtain a high-quality titanium ingot.

2. The VAR smelting method for preparing high-quality titanium ingots by vertical pressing electrodes according to claim 1, characterized in that: The pressing electrode has a diameter φ of 470-820 mm and a core inner diameter φ of 80-85 mm.

3. The VAR smelting method for preparing high-quality titanium ingots by vertical pressing electrodes according to claim 2, characterized in that: The specification of the center rod is φ77-83 (±0.5) mm×L, where L is the actual length of the electrode; the composition of the center rod is consistent with that of the electrode, its surface is smooth and free of oxide scale, and the end is flattened.

4. The VAR smelting method for preparing high-quality titanium ingots by vertical pressing electrodes according to claim 1, characterized in that: The step 2 before welding includes: Start the vacuum pump to extract the air in the furnace and control the vacuum degree in the furnace to ≤5Pa before welding.

5. The VAR smelting method for preparing high-quality titanium ingots by vertical pressing electrodes according to claim 1, characterized in that: The welding current is 3-12 kA, the voltage is 28-36 V, and a primary welding electrode is obtained after welding. After cooling for more than 45 minutes, the electrode is taken out of the furnace for inspection.

6. The VAR smelting method for preparing high-quality titanium ingots by vertical pressing electrodes according to claim 1, characterized in that: The step three specifically includes: controlling the melting speed of the consumable electrode by adjusting the current to keep the arc stable.

7. The VAR smelting method for preparing high-quality titanium ingots by vertical pressing electrodes according to claim 6, characterized in that: The consumable electrode is melted twice, the first melting current is 15-26kA, the second melting current is 20-36kA, and the arc is stable at a current of 9-20A.

8. The VAR smelting method for preparing high-quality titanium ingots by vertical pressing electrodes according to claim 6, characterized in that: During the smelting process, the molten titanium metal drips into a crystallizer and gradually forms an ingot.

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