A method for preparing WCu alloy by eddy current thermoelectric coupling

Abstract

The present application relates to a kind of vortex thermoelectric coupling preparation WCu alloy method, belong to metallurgical technical field, the present application includes the following steps: preparation Cu block, WO3 Powder, metal reducing agent, slagging agent, after Cu block is melted, vortex is formed in copper melt using the synergistic effect of additional stirring and electromagnetic induction, WO3 Powder, metal reducing agent and the mixture of slagging agent are added in copper melt by vortex method smelting, obtain W melt and intermediate product, using the synergistic effect of additional stirring and electromagnetic induction, W melt and Cu melt are uniformly mixed to obtain homogeneous WCu alloy melt and reduced slag, the homogeneous WCu alloy melt is casted and cooled to prepare WCu alloy.The present application uses WO3 Raw material, utilizes the heat released by itself reaction, does not need additional heat supply, does not need to prepare self-consumption electrode, greatly reduces production cost;Calcium aluminate slag system generated by the present application can be prepared calcium aluminate cement clinker and used as refractory material, no waste is discharged in whole process, realize clean preparation WCu alloy.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metallurgy, and particularly relates to a method for preparing WCu alloy through vortex heat and thermoelectric coupling. BACKGROUND

[0002] Tungsten-copper composite material is a two-phase structure "pseudo-alloy" with the properties of both tungsten and copper, and has high density, high tensile strength, good thermal and electrical conductivity and other excellent properties, thus having important research value and broad application prospect in the fields of aerospace, military industry, electronics and electrical engineering. Since the melting points of tungsten and copper are quite different, and the solubility of tungsten and copper is extremely low, the relative density of tungsten-copper composite material prepared by using traditional powder metallurgy preparation process does not meet the requirements, and the microstructure of the material is also uneven, so the potential of the material has not been fully tapped. At present, the research on tungsten-copper composite material mainly focuses on developing new preparation processes and adding new alloy elements or non-metallic compounds to improve the performance of the material. In particular, the development of new tungsten-copper composite material preparation processes is accompanied by new applications of tungsten-copper composite material, especially the tungsten-copper composite material used for electrical contacts, which puts forward higher and higher performance requirements and service life requirements, which puts forward new research requirements for the process means of the material. Therefore, the exploration of the preparation process of tungsten-copper composite material has positive practical significance and good application prospect for further developing and producing tungsten-copper composite material with higher performance.

[0003] At present, the preparation process of WCu alloy is infiltration method, which is also called melting immersion method. Tungsten powder or tungsten powder mixed with part of induced copper powder is pressed into a suitable size blank by a static press, and then pre-sintered to prepare a porous tungsten composition matrix skeleton with good structure and excellent performance at a temperature higher than the melting point of copper. Subsequently, the metal copper with a lower melting point is melted and infiltrated into the porous tungsten composition matrix skeleton under vacuum or reducing / protection atmosphere, so as to obtain tungsten-copper composite material with higher densification. This process is mainly suitable for manufacturing tungsten-copper composite material with high purity and mass fraction ≤15%, and has the problems of long production cycle, complex production process and high production cost. At present, it is the research direction of WCu alloy to prepare WCu alloy with performance equivalent to or even better than commercial alloy to obtain good economic benefits. SUMMARY

[0004] To solve the above technical problems, the application provides a method for preparing WCu alloy by vortex thermoelectric coupling, which comprises the following steps: preparing raw materials according to the required WCu alloy, preparing Cu block, WO3 powder, metal reducing agent and slagging agent, melting the Cu block, forming vortex in the copper melt by using external stirring and electromagnetic induction, adding the mixture of WO3 powder, metal reducing agent and slagging agent into the copper melt by vortex method for smelting, obtaining W melt and intermediate product, uniformly mixing the W melt and Cu melt by using external stirring and electromagnetic induction to obtain homogeneous WCu alloy melt and reduced slag, and obtaining WCu alloy by casting and cooling the homogeneous WCu alloy melt.

[0005] Further, the metal reducing agent is any one of Al, Ca and Mg powder; if the metal reducing agent is Al powder, the slagging agent is CaO, and if the metal reducing agent is Ca or Mg powder, the slagging agent is Al2O3.

[0006] Further, the vortex is formed in the copper melt by vortex mechanical stirring, and the external stirring uses straight-blade open turbine paddle with stirring speed of 300-400 rpm.

[0007] Further, the raw material ratio is that the addition amount of WO3 is 1.2-1.5 times of the stoichiometric amount, and the addition amount of W is controlled in the range of 50%-80%.

[0008] 2Al+(1.2-1.5)WO3+xCaO→W+2Al2O3·xCaO (1)

[0009] 3Ca+(1.2-1.5)WO3+xAl2O3→W+xAl2O3·3CaO (2)

[0010] 3Mg+(1.2-1.5)WO3+3Al2O3→W+3MgAl2O4 (3).

[0011] Further, the electromagnetic frequency of the electromagnetic induction is 2000-5000 Hz, the smelting temperature is 1700-1800 ℃, and the time is 10-15 min.

[0012] Further, the added slagging agent and the intermediate product generated in situ by reaction form reduced slag, the intermediate product is Al2O3, CaO or MgO melt, the melting point of the reduced slag is about 1600 ℃-1800 ℃, and a slag protection layer is formed on the surface of the melt.

[0013] Further, the reduced slag is Al2O3-CaO slag or MgAl2O4 slag, and the Al2O3-CaO slag or MgAl2O4 slag is directly prepared into calcium aluminate cement clinker or refractory material by water quenching at 1600-1800 ℃ using the overflow slagging method.

[0014] Further, the WCu alloy is cast into a water-cooled crystallizer and rapidly solidified at a solidification speed of 10-15 ℃ / s to obtain homogeneous and dense WCu.

[0015] The present application has the following beneficial effects:

[0016] (1) Compared with the vacuum consumable process, the present application uses WO3 raw material, utilizes the heat released by the reaction, does not need additional heat supply, does not need to prepare a consumable electrode, shortens the process flow, and greatly reduces the production cost.

[0017] (2) The process uses the synergistic effect of electromagnetic stirring and eddy current stirring to uniformly disperse W single element in the Cu matrix, and the rapid cooling of the water-cooled crystallizer effectively suppresses segregation.

[0018] (3) The calcium aluminate slag generated by the present application can be used to prepare calcium aluminate cement clinker, and the generated MgAl2O4 slag can be used as refractory material, and the whole process does not discharge waste, realizing clean preparation of WCu alloy. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0020] Embodiment 1

[0021] According to the composition of the WCu20 ingot to be prepared, Cu blocks, WO3, Al powder and CaO are prepared, and the required WO3 and CaO for the reaction are placed in an oven at 150 ℃ for 24 h.

[0022] Put 2kg Cu block into induction furnace, heat up to 1300℃ to make Cu block completely melt, present melt state, add mechanical stirring system. Set stirring speed to 150rpm. When mixing ingredients, put 10087g WO3 powder and 2348g Al powder and 2435g CaO into mixing tank, mix for 40min on ball mill. After mixing, add into melt in batches by vortex of melt, generate W element inside melt by aluminothermic reduction reaction, and disperse in melt inside by mechanical stirring and electromagnetic stirring, finally get high temperature melt composed of alloy melt and Al2O3-CaO reduction slag, carry out alloy slag smelting of high temperature melt under action of electromagnetic field, electromagnetic induction parameters are: 5000Hz, smelting temperature is 1800℃, smelting time is 15min, upper layer forms reduction slag, lower layer forms alloy melt; after refining and deslagging, carry out rapid solidification of WCu20 alloy ingot under action of water cooling, Cu content in alloy is 19-21%.

[0023] Example 2

[0024] Prepare Cu block, WO3, Al powder and CaO according to ingredients of WCu30 gold ingot to be prepared, place WO3 and CaO required for reaction in oven at 150℃ for 24h.

[0025] Put 2kg Cu block into induction furnace, heat up to 1300℃ to make Cu block completely melt, present melt state, add mechanical stirring system. Set stirring speed to 130rpm. When mixing ingredients, put 5043.77g WO3 powder and 1173.91g Al powder and 1217.39g CaO into mixing tank, mix for 40min on ball mill. After mixing, add into melt in batches by vortex of melt, generate W element inside melt by aluminothermic reduction reaction, and disperse in melt inside by mechanical stirring and electromagnetic stirring, finally get high temperature melt composed of alloy melt and Al2O3-CaO reduction slag, carry out alloy slag smelting of high temperature melt under action of electromagnetic field, electromagnetic induction parameters are: 3500Hz, smelting temperature is 1750℃, smelting time is 13min, upper layer forms reduction slag, lower layer forms alloy melt; after refining and deslagging, carry out rapid solidification of WCu30 alloy ingot under action of water cooling, Cu content in alloy is 29-32%.

[0026] Example 3

[0027] Prepare Cu block, WO3, Al powder and CaO according to ingredients of WCu40 gold ingot to be prepared, place WO3 and CaO required for reaction in oven at 150℃ for 24h.

[0028] Put 2kg Cu block into induction furnace, heat up to 1300℃ to make Cu block completely melt, present melt state, add mechanical stirring system. Set stirring speed to 125rpm. When mixing ingredients, put 3782g WO3 powder and 880.43g Al powder and 913g CaO into mixing tank, mix for 40min on ball mill. After mixing, add into melt in batches through vortex of melt, generate W element inside melt through aluminothermic reduction reaction, and disperse inside melt through mechanical stirring and electromagnetic stirring, finally get high temperature melt composed of alloy melt and Al2O3-CaO reduction slag, carry out alloy slag smelting of high temperature melt under action of electromagnetic field, electromagnetic induction parameters are: 3000Hz, smelting temperature 1750℃, smelting time is 12min, upper layer forms reduction slag, lower layer forms alloy melt; after refining and deslagging, carry out rapid solidification of WCu40 alloy ingot under action of water cooling, Cu content in alloy is 38-42%.

[0029] Example 4

[0030] Prepare Cu block, WO3, Al powder and CaO according to composition of WCu50 gold ingot to be prepared, place WO3 and Al2O3 required for reaction in oven at 150℃ for 24h.

[0031] Put 2kg Cu block into induction furnace, heat up to 1300℃ to make Cu block completely melt, present melt state, add mechanical stirring system. Set stirring speed to 125rpm. When mixing ingredients, put 3782g WO3 powder and 880.43g Al powder and 913g CaO into mixing tank, mix for 40min on ball mill. After mixing, add into melt in batches through vortex of melt, generate W element inside melt through aluminothermic reduction reaction, and disperse inside melt through mechanical stirring and electromagnetic stirring, finally get high temperature melt composed of alloy melt and Al2O3-CaO reduction slag, carry out alloy slag smelting of high temperature melt under action of electromagnetic field, electromagnetic induction parameters are: 3000Hz, smelting temperature 1750℃, smelting time is 12min, upper layer forms reduction slag, lower layer forms alloy melt; after refining and deslagging, carry out rapid solidification of WCu40 alloy ingot under action of water cooling, Cu content in alloy is 38-42%.

[0032] Example 5

[0033] Prepare Cu block, WO3, Ca powder and Al2O3 according to composition of WCu50 gold ingot to be prepared, place WO3 and Al2O3 required for reaction in oven at 150℃ for 24h.

[0034] 2 kg of Cu blocks were placed in an induction furnace and heated to 1300℃ until the Cu blocks were completely melted and in a molten state. The mixture was then added to a mechanical stirring system. The stirring speed was set to 120 rpm. For mixing, 2521.74 g of WO3 powder, 880.43 g of Ca powder, and 2660.87 g of Al2O3 were placed in a mixing tank and mixed in a ball mill for 40 minutes. After mixing, the mixture is added to the melt in batches through a vortex. Aluminothermic reduction reaction generates elemental W within the melt, which is then dispersed within the melt by mechanical and electromagnetic stirring. The final product is a high-temperature melt composed of the alloy melt and Al2O3-CaO reducing slag. This high-temperature melt is then subjected to alloy slag smelting under an electromagnetic field with the following parameters: 2500 Hz, 1700℃, and 13 min. A reducing slag forms on the upper layer, and the alloy melt forms on the lower layer. After refining and slag removal, the WCu50 alloy ingot is rapidly solidified under water cooling. The Cu content in the alloy is 49-51%.

[0035] Example 6

[0036] Prepare Cu blocks, WO3, Al powder and CaO according to the composition of the WCu50 gold ingot to be prepared. Place the WO3 and CaO required for the reaction in an oven and dry at 150°C for 24 hours.

[0037] 2 kg of Cu blocks were placed in an induction furnace and heated to 1300℃ until the Cu blocks were completely melted and in a molten state. A mechanical stirring system was then added, with the stirring speed set to 100 rpm. For mixing, 2521.74 g of WO3 powder, 880 g of Mg powder, and 3326 g of Al2O3 were placed in a mixing tank and mixed in a ball mill for 40 minutes. After mixing, the mixture is added to the melt in batches through a vortex. Elemental W is generated inside the melt through an aluminothermic reduction reaction and dispersed inside the melt by mechanical and electromagnetic stirring. Finally, a high-temperature melt composed of alloy melt and MgAl2O4 reducing slag is obtained. The high-temperature melt is then smelted into alloy slag under the action of an electromagnetic field. The electromagnetic induction parameters are: 3000Hz, smelting temperature 1750℃, and smelting time 15min. A reducing slag is formed on the upper layer, and an alloy melt is formed in the lower layer. After refining and slag removal, WCu50 alloy ingots are rapidly solidified under water cooling. The Cu content in the alloy is 48-50%.

Claims

1. A method for preparing WCu alloys via eddy current thermoelectric coupling, characterized in that, According to the required WCu alloy, the raw material ratio is prepared, including Cu blocks, WO3 powder, metal reducing agent, and slag-forming agent. After the Cu blocks are melted, an eddy current is formed in the copper melt under the combined action of external stirring and electromagnetic induction. The mixture of WO3 powder, metal reducing agent, and slag-forming agent is added to the copper melt through the eddy current and smelted to obtain W melt and intermediate products. The W melt and Cu melt are uniformly mixed under the combined action of external stirring and electromagnetic induction to obtain a homogeneous WCu alloy melt and reducing slag. The homogeneous WCu alloy melt is cast and cooled to obtain the WCu alloy. The metal reducing agent is any one of Al, Ca, and Mg powder; if the metal reducing agent is Al powder, the slag-forming agent is CaO; if the metal reducing agent is Ca or Mg powder, the slag-forming agent is Al2O3. The raw material ratio is as follows: the amount of WO3 added is 1.2 to 1.5 times the chemical reaction stoichiometry, and the amount of W added is controlled within the range of 50% to 80%. （1） （2） （3）。 2. The method for preparing WCu alloy by eddy current thermoelectric coupling according to claim 1, characterized in that, The eddy current is formed in the copper molten body by eddy current mechanical stirring. The external stirring uses a straight-blade open turbine propeller with a stirring speed of 300~400 rpm.

3. The method for preparing WCu alloy by eddy current thermoelectric coupling according to claim 1, characterized in that, The electromagnetic frequency of the electromagnetic induction is 2000-5000Hz, the melting temperature is 1700-1800℃, and the time is 10-15 min.

4. The method for preparing WCu alloy by eddy current thermoelectric coupling according to claim 1, characterized in that, The added slag-forming agent and the intermediate product generated in situ from the reaction form a reducing slag. The intermediate product is an Al2O3, CaO, or MgO melt. The melting point of the reducing slag is 1600℃~1800℃, and a slag protective layer is formed on the surface of the melt.

5. The method for preparing WCu alloy by eddy current thermoelectric coupling according to claim 1, characterized in that, The reducing slag is Al2O3-CaO slag or MgAl2O4 slag. The Al2O3-CaO slag or MgAl2O4 slag is directly quenched in water at 1600℃~1800℃ using the overflow slag discharge method to prepare calcium aluminate cement clinker or refractory materials.

6. The method for preparing WCu alloy by eddy current thermoelectric coupling according to claim 1, characterized in that, The WCu alloy was cast into a water-cooled crystallizer and rapidly solidified at a solidification rate of 10~15℃ / s to obtain homogeneous and dense WCu.

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