Preparation method of titanium alloy containing rare precious metal elements

Abstract

The preparation method of the titanium alloy containing the rare precious metal elements comprises the following steps that raw materials are prepared, specifically, micro-particle sponge titanium with the particle size being 0.5-2 mm is included; rare precious metal powder; industrial alcohol; the particle size of the national standard grade sponge titanium is 3-12.7 mm; mixing the materials for the first time; s201, the surface of the micro-particle sponge titanium is wetted with alcohol and stirred; the micro-particle sponge titanium and rare precious metal powder are evenly mixed according to the mass ratio of (14-15): 1, the rare precious metal powder adheres to the micro-particle sponge titanium, and mixed powder is formed to serve as intermediate alloy; material mixing is conducted again, specifically, the intermediate alloy and the national standard grade sponge titanium are evenly mixed according to the preset mass ratio, and a pre-smelting alloy is obtained; the pre-smelted alloy is fed into a die cavity of a hydraulic machine to be pressed into an electrode block, and the pressure is 50-60 MN; a plurality of electrode blocks are welded into a consumable electrode in a vacuum plasma welding mode, and the pressure of a furnace chamber is 10000-25000Pa; and the consumable electrode is subjected to secondary smelting through a vacuum consumable smelting method, and the titanium alloy is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of titanium alloy processing, and in particular to a method for preparing a titanium alloy containing rare noble metal elements. Background Art

[0002] Titanium alloys are widely used in aerospace, automobile, medical equipment and other fields due to their excellent mechanical properties, corrosion resistance and biocompatibility. Adding trace precious alloying elements such as Pd and Ru to titanium alloys can significantly improve the performance of titanium alloys. For example, TA8 (Ti-0.05Pd) and TA9 (Ti-0.2Pd) add 0.05-0.2% Pd to titanium, and their corrosion resistance can be increased several times. The traditional titanium alloy production method usually mixes pure metal or metal oxide powder with titanium powder, and then makes titanium alloy by hot isostatic pressing or hot extrusion. Although this method is simple, it is difficult to ensure the uniform distribution of alloying elements due to the very low content of trace elements such as Pd and Ru, resulting in component segregation of titanium alloys and affecting the performance of titanium alloys.

[0003] In order to ensure that trace elements such as Pd and Ru are evenly mixed, electrode blocks are generally made in a layered manner, and then smelted multiple times. The specific process is to lay the trace elements on sponge titanium particles, then lay sponge titanium particles, and then lay the trace elements, layer by layer. In order to ensure uniform laying, the process is very slow. In order to improve the laying efficiency, trace elements are also wrapped in titanium foil to form trace element packages, and then the trace element packages are laid on sponge titanium. This process still requires manual laying, and the efficiency is relatively low. Summary of the invention

[0004] In view of this, it is necessary to provide a method for preparing a titanium alloy containing rare precious metal elements so as to improve production efficiency while ensuring the uniformity of the rare precious metal elements.

[0005] A method for preparing a titanium alloy containing rare noble metal elements comprises the following steps:

[0006] Step S1: Raw material preparation, including

[0007] Tiny particles of titanium sponge, with a particle size of 0.5 to 2 mm;

[0008] Rare and precious metal powders;

[0009] Industrial alcohol;

[0010] National standard grade titanium sponge, particle size is 3-12.7mm;

[0011] Step S2: first mixing;

[0012] Step S201, wetting the surface of the tiny particle titanium sponge with alcohol and stirring;

[0013] Step S202, uniformly mixing the tiny particle titanium sponge and the rare precious metal powder in a mass ratio of (14-15):1, so that the rare precious metal powder adheres to the tiny particle titanium sponge to form a mixed powder as an intermediate alloy;

[0014] Step S3: mixing the materials again, mixing the master alloy and the national standard grade titanium sponge uniformly according to a predetermined mass ratio to obtain a pre-melted alloy;

[0015] Step S4: feeding the pre-melted alloy into the mold cavity of a hydraulic press and pressing it into an electrode block at a pressure of 50 to 60 MN;

[0016] Step S5: welding the plurality of electrode blocks into consumable electrodes by vacuum plasma welding, with the furnace chamber pressure being 10000-25000 Pa;

[0017] Step S6: performing secondary smelting of the consumable electrode by vacuum consumable smelting method to obtain titanium alloy.

[0018] Beneficial effects: Compared with the prior art, the present invention first soaks the micro-particle titanium sponge with alcohol, and then mixes the rare metal powder with the micro-particle titanium sponge. The adhesion of the micro-particle titanium sponge after soaking and its own looseness are used to enable the rare metal powder to be fully and relatively firmly adsorbed on the surface of the micro-particle titanium sponge. At the same time, the mixing ratio of micro-particle titanium sponge and rare metal powder is low, and the two can be mixed evenly. When mixed with the national standard grade titanium sponge later, the evenly mixed intermediate alloy is mixed with the national standard grade titanium sponge again. Such layered mixing allows the rare metal powder to be fully mixed. The entire mixing process does not have a time-consuming and labor-intensive layering link, so it is more efficient. At the same time, there is no generation of floating dust in the entire mixing process, which reduces the loss of rare metal powder and reduces production costs. DETAILED DESCRIPTION

[0019] In order to facilitate the understanding of the present application, the present application will be described in more detail below. And the preferred embodiments of the present application are given. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thoroughly understood.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0021] A method for preparing a titanium alloy containing rare noble metal elements comprises the following steps:

[0022] Step S1: Raw material preparation, including

[0023] Tiny particles of titanium sponge, with a particle size of 0.5 to 2 mm;

[0024] Rare and precious metal powders;

[0025] Industrial alcohol;

[0026] National standard grade titanium sponge, particle size is 3-12.7mm;

[0027] Step S2: first mixing;

[0028] Step S201, wetting the surface of the tiny particle titanium sponge with alcohol and stirring;

[0029] The surface of titanium sponge has many gaps, which can absorb rare and precious metal powders. However, the adsorption capacity of dry titanium sponge is poor. After mixing with precious metal powders, it is easy to cause uneven mixing, and the prepared titanium alloy is prone to component segregation. After experiments, it was found that the adsorption capacity of titanium sponge can be significantly improved after the surface of titanium sponge is moistened with alcohol.

[0030] The tiny particles of titanium sponge of the present invention come from the materials to be recycled after the titanium ingots are crushed. Generally, the titanium material used to produce titanium alloys is national standard grade titanium sponge. After the titanium ingots are crushed, the qualified materials are national standard grade titanium sponge, and the smaller titanium sponge particles are recycled to prepare titanium ingots again. The present invention wets part of the tiny particles of titanium sponge to be recycled as raw materials, which has a low cost.

[0031] The advantage of alcohol is that it is volatile and has a certain degree of anti-oxidation. During the mixing process, the titanium surface is not easily oxidized, resulting in a high oxygen content in the final alloy. In the subsequent smelting process, the residual alcohol will evaporate and will not affect the content of the titanium alloy.

[0032] During the wetting process, alcohol aggregation should not be formed, so as to avoid excessive alcohol, which will wash the rare and precious metal powder into the alcohol, resulting in uneven distribution of tiny particles of titanium sponge and precious metal powder. At the same time, if there is too little alcohol, it will evaporate too quickly, making the tiny particles of titanium sponge too dry, and the rare and precious metal powder will fall to the bottom of the material along the gap.

[0033] At the same time, the particle size of the micro-particle titanium sponge cannot be too large. If the particle size of the micro-particle titanium sponge is too large, the gaps between the micro-particle titanium sponge will be too large, and some rare precious metal powders that have no time to adhere will fall to the bottom of the material along the gaps. At the same time, the rare precious metal powders will also adhere unevenly on the surface of the micro-particle titanium sponge, affecting the uniformity of the rare precious metals in the subsequent titanium alloy.

[0034] At the same time, the particle size of the micro-particle titanium sponge cannot be too small. If the particle size of the micro-particle titanium sponge is too small, some rare and precious metal powders will not be able to adhere to the micro-particle titanium sponge, or the adhesion will not be reliable, resulting in the subsequent mixing with the national standard grade titanium sponge. The rare and precious metal powder will slide off the micro-particle titanium sponge and slide down along the gaps of the material, causing uneven materials.

[0035] In a preferred embodiment, the rare and precious metal powder is palladium or ruthenium to improve the corrosion resistance of the titanium alloy. The particle size of palladium or ruthenium is 0.5 to 5 microns.

[0036] Step S202, uniformly mixing tiny particle titanium sponge and rare precious metal powder in a mass ratio of (14-15):1, so that the rare precious metal powder adheres to the tiny particle titanium sponge to form a mixed powder as an intermediate alloy;

[0037] If the mixing ratio of tiny particle titanium sponge and rare precious metal powder is too large, then during the mixing process, the amount of rare precious metal powder adhering to different tiny particle titanium sponge will vary greatly, resulting in uneven final mixing.

[0038] If the mixing ratio of tiny particle titanium sponge and rare precious metal powder is too small, some of the rare precious metal powder will not adhere to the tiny particle titanium sponge, or the adhesion will not be strong, resulting in uneven subsequent mixing. At the same time, when the mixing ratio of tiny particle titanium sponge and rare precious metal powder is too small, the ratio of the formed intermediate alloy to the national standard grade titanium sponge will become larger, that is, in order to make the content of rare precious metal powder in the final titanium alloy meet the requirements, more national standard grade titanium sponge needs to be added, and the mixing effect becomes worse.

[0039] Step S3: mixing the materials again, mixing the master alloy and the national standard grade titanium sponge uniformly according to a predetermined mass ratio to obtain a pre-melted alloy;

[0040] In a preferred embodiment, the mass ratio of the master alloy to the national standard grade titanium sponge is 3:(120-140). The specific mass ratio is determined according to the content of rare and precious metals in the final titanium alloy.

[0041] Step S4: feeding the pre-melted alloy into the mold cavity of a hydraulic press and pressing it into an electrode block at a pressure of 50 to 60 MN;

[0042] Step S5: welding the plurality of electrode blocks into consumable electrodes by vacuum plasma welding, with the furnace chamber pressure being 10000-25000 Pa;

[0043] Step S6: performing secondary smelting of the consumable electrode by vacuum consumable smelting method to obtain titanium alloy.

[0044] The following is a preferred embodiment of the present invention.

[0045] Raw material preparation: micro-particle titanium sponge, particle size of 0.5-2mm; rare and precious metal powder; industrial alcohol; national standard grade titanium sponge, particle size of 3-12.7mm. The mass ratio of micro-particle titanium sponge to rare and precious metal powder is (14-15): 1; national standard grade titanium sponge is prepared according to the mass ratio;

[0046] First mixing: First, weigh the tiny particles of titanium sponge into the container, then wet the surface with industrial alcohol (unless alcohol aggregation is formed) and stir evenly, and finally pour the rare precious metal powder into the container and stir evenly, so that the rare metal element powder adheres to the titanium tiny particles to form a mixed powder as an intermediate alloy;

[0047] Second mixing: Use a mixing system to mix the 3-12.7 mm particle titanium sponge and the master alloy in the national standard GB / T 2524-2002 evenly through the mixing system, and the mixing time is 45 seconds;

[0048] Pressing consumable electrodes: feeding the above-obtained materials into the mold cavity of a hydraulic press and pressing them into electrode blocks with a pressing force of about 50 to 60 MN;

[0049] Welding consumable electrodes: The above-obtained multiple electrode blocks are welded into consumable electrodes by vacuum plasma welding. The vacuum plasma welding box is welded under argon protection. The furnace chamber pressure is 10000-25000Pa. The welding current and voltage are related to the specifications of the consumable electrode. This is conventional welding and will not be described in detail.

[0050] Primary vacuum smelting: The primary alloy ingot is smelted by vacuum consumable smelting method. Before smelting, the inner wall of the water-cooled copper crucible must be cleaned, and the welded electrodes are loaded into the furnace. The auxiliary electrodes are welded in the furnace. The vacuum degree of the furnace body before smelting is ≤0.6Pa, and the leakage rate is ≤0.5Pa / min. The smelting current, voltage and smelting rate in the stable smelting stage are related to the specifications of the smelted ingot. This is conventional smelting and will not be described in detail.

[0051] Ingot appearance treatment: Use a lathe to machine and flatten the crown of the first-melting ingot;

[0052] Secondary vacuum smelting: The secondary alloy ingot is smelted by vacuum consumable smelting method. Before smelting, the inner wall of the water-cooled copper crucible must be cleaned first, and the primary alloy ingot is placed upside down in the furnace. The auxiliary electrode is welded in the furnace. The vacuum degree of the furnace body before smelting is ≤0.6Pa, and the leakage rate is ≤0.5Pa / min; the smelting current, voltage and smelting rate in the stable smelting stage are related to the specifications of the smelted ingot. This is conventional smelting and will not be explained in detail.

[0053] Ingot peeling: Use lathe to peel the secondary smelting ingot, and make sure there are no large-area pores or defects on the surface;

[0054] Ingot inspection: The content of each alloy and interstitial gas element is tested on the test sample; non-destructive ultrasonic flaw detector is used to detect internal defects of the ingot and determine the position of the riser.

[0055] Through the above steps, the titanium alloy containing trace amounts of rare and precious metal powders of the present invention is obtained.

[0056] The above preparation process is an industrialized production process with cost advantages. The prepared titanium alloy has good corrosion resistance and biocompatibility.

[0057] In actual production, 60 electrodes are generally used to melt an ingot. In order to verify that the method for preparing a titanium alloy containing rare precious metal elements of the present invention can mix rare precious metal elements more evenly than the prior art, the inventors took the same batch of tiny particle titanium sponge, palladium metal powder and national standard titanium sponge for testing. The amount of raw materials added each time is the amount used to prepare one electrode block.

[0058] Test 1: Mixing is carried out according to the mixing method of the present invention, and the specific operation is as follows:

[0059] 3000 grams of tiny particle titanium sponge is weighed into a container, and then the surface is moistened with industrial alcohol (unless alcohol aggregation is formed) and stirred evenly. 210 grams of palladium metal powder is poured into the container and stirred thoroughly to form an intermediate alloy. The intermediate alloy is then stirred thoroughly with 135 kilograms of national standard grade titanium sponge to form a smelting alloy.

[0060] In the second experiment, 3000 grams of tiny particle titanium sponge, 210 grams of palladium metal powder, and 135 kilograms of national standard grade titanium sponge were poured into a container and stirred thoroughly to form a pre-melted alloy.

[0061] In test three, the surface of 138 kg of national standard grade sponge titanium was moistened with industrial alcohol (unless alcohol aggregation was formed) and then stirred evenly. 210 g of palladium metal powder was poured into the container and stirred thoroughly to form a pre-melted alloy.

[0062] In the above three tests, 9 test points were taken from the pre-melted alloy of each test, at the top, middle and bottom positions of the pre-melted alloy, and 3 test points were taken from each position, where test points 1, 2 and 3 were located at the top of the pre-melted alloy, test points 4, 5 and 6 were located at the middle of the pre-melted alloy, and test points 7, 8 and 9 were located at the bottom of the pre-melted alloy. 10 grams of sample was weighed for each test point, and the palladium metal content test results of each test point are shown in Table 1.

[0063] Table 1: Palladium metal content of each sample

[0064] Test 1 Palladium content (%) Test dipalladium content (%) Test three palladium content (%) Check point 1 0.152 0.128 0.139 Check point 2 0.146 0.126 0.141 Check point three 0.149 0.123 0.136 Check point four 0.151 0.149 0.146 Check point five 0.154 0.151 0.147 Check point six 0.150 0.145 0.158 Check point seven 0.152 0.179 0.166 Check point eight 0.153 0.178 0.168 Check Point Nine 0.155 0.180 0.165 variance 0.00001 0.00054 0.00016

[0065] It can be seen from the test results in Table 1 that the variance of each test point in Test 1 is significantly smaller than that in Test 2 and Test 3, indicating that the palladium component distribution of the pre-melted alloy in Test 1 is more uniform. Especially compared with Test 2, the micro-particle titanium sponge is mixed with the palladium metal powder after being wetted with alcohol, and then mixed with the national standard grade titanium sponge. This mixing method is more uniform than directly mixing the three without wetting with alcohol, especially from top to bottom, the palladium metal powder is not easy to roll down from the gap to the bottom of the pre-melted alloy, thereby making the palladium distribution more uniform. At the same time, compared with the transition without mixing micro-particle titanium sponge, directly wetting with alcohol, the uniformity of mixing in Test 1, i.e., the method of the present invention, is better.

[0066] What is disclosed above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for preparing a titanium alloy containing rare precious metal elements, characterized in that: The following steps are involved: Step S1: Raw material preparation, including Tiny particles of titanium sponge, with a particle size of 0.5~2mm; Rare and precious metal powders; Industrial alcohol; National standard grade titanium sponge, particle size is 3~12.7mm; Step S2: first mixing; Step S201, wetting the surface of the tiny particle titanium sponge with alcohol and stirring; Step S202, uniformly mixing tiny particle titanium sponge and rare precious metal powder in a mass ratio of (14-15):1, so that the rare precious metal powder adheres to the tiny particle titanium sponge to form a mixed powder as an intermediate alloy; Step S3: mixing the materials again, mixing the master alloy and the national standard grade titanium sponge uniformly according to a predetermined mass ratio to obtain a pre-melted alloy; Step S4: feeding the pre-melted alloy into the mold cavity of a hydraulic press and pressing it into an electrode block at a pressure of 50-60 MN; Step S5: welding the plurality of electrode blocks into consumable electrodes by vacuum plasma welding, with the furnace chamber pressure being 10000-25000 Pa; Step S6: performing secondary smelting of the consumable electrode by vacuum consumable smelting method to obtain titanium alloy.

2. The method for preparing a titanium alloy containing rare noble metal elements according to claim 1, characterized in that: The rare and precious metal powder is palladium or ruthenium, and the particle size of palladium or ruthenium is 0.5-5 microns.

3. The method for preparing a titanium alloy containing rare noble metal elements according to claim 1, characterized in that: The mass ratio of the intermediate alloy to the national standard grade titanium sponge is 3: (120~140).