Copper-tin alloy heating wire and preparation method thereof

Abstract

The present invention relates to the technical field of heating wire preparation, and specifically to a copper-tin alloy heating wire and a preparation method thereof, wherein the copper-tin alloy heating wire comprises raw materials including: 1.5wt%-2.0wt% tin, 0.1wt%-0.3wt% silver, 0.03wt%-0.05wt% zinc, 0.05wt%-0.1wt% lanthanum, and the remainder is copper and unavoidable impurities. The present invention can obtain a copper-tin alloy heating wire with high tensile strength and excellent bending resistance even when the upper continuous casting method is adopted through the mutual coordination of various elements. The copper-tin alloy heating wire prepared by the present invention has the advantages of high purity, fine grain structure, good high temperature resistance, stable conductivity, etc., and the tensile strength is ≥800MPa, the oxygen content is ≤3ppm, and the number of repeated bendings without breaking is ≥10 times.

Description

Technical Field

[0001] The invention relates to the technical field of heating wire preparation, and in particular to a copper-tin alloy heating wire and a preparation method thereof. Background Art

[0002] The heating wire is a common heating element, which generates heat after being powered on, converting electrical energy into thermal energy. The application range of heating wires is very wide, and they are widely used in various industries such as medical, chemical, electronic, electrical, metallurgical machinery, ceramic glass processing, etc. At the same time, due to the different fields of use, the existing heating wires are also required to achieve a higher wiring density by reducing the resistivity. This places higher and higher requirements on the strength of the heating wires and their anti-bending performance. Not only must the strength of the heating wires be guaranteed, but they must also have good anti-bending performance. However, the current heating wires have uneven resistance and poor anti-bending performance, and are prone to leakage, short circuit, poor contact and other problems.

[0003] Traditional high-resistance electric heating alloy heating wires include iron-chromium-aluminum alloy heating wires, nickel-chromium alloy heating wires or copper-tin alloy heating wires, etc. Different types of heating wires have different functional characteristics as electric heating elements. Among them, the iron-chromium-aluminum alloy heating wire has a high operating temperature, a long service life, a high resistivity, a high surface composite, and good oxidation resistance, but it is easy to deform at high temperatures and difficult to repair after deformation. The nickel-chromium alloy heating wire has high strength in a high temperature environment, is not easy to deform during long-term high-temperature operation, and has good room-temperature plasticity, and is relatively simple to repair after deformation. In addition, the nickel-chromium alloy heating wire has high emissivity, is non-magnetic, has good corrosion resistance, and has a long service life, but it cannot reach the level of the iron-chromium-aluminum alloy heating wire in terms of operating temperature, and the price of nickel metal is relatively expensive. Therefore, the manufacturing cost of the nickel-chromium alloy heating wire is high, which is not conducive to cost control. The solidus and liquidus temperature difference of the copper-tin alloy is large, which makes casting difficult; specifically, most of the existing copper-tin alloy casting rods are prepared by upward continuous casting or vacuum melting + continuous casting. When copper-tin alloy casting rods are made by vacuum melting + continuous casting, although the quality of the casting rods can be guaranteed, they can only be produced in small batches, and the inspection workload is large and the cost is high, which is not suitable for mass production. The existing upward continuous casting method can be used to prepare copper-tin alloy casting rods. Although it can be produced in large quantities, it is often due to the low cooling intensity that can be achieved, which causes the alloy to easily undergo reverse segregation during the solidification process, resulting in uneven alloy composition, gray-white tin-rich secretions on the surface, and poor surface quality, which in turn leads to the strength and anti-bending properties of the final copper-tin alloy heating wire not meeting the requirements; and the oxygen content is high, which affects subsequent processing. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that the strength and bending resistance of the copper-tin alloy heating wire finally obtained cannot meet the requirements when the conventional copper-tin alloy heating wire is prepared by the upper casting rod preparation process, thereby providing a copper-tin alloy heating wire and a preparation method thereof that solve the above problems.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A copper-tin alloy heating wire comprises raw materials including: 1.5wt%-2.0wt% tin, 0.1wt%-0.3wt% silver, 0.03wt%-0.05wt% zinc, 0.05wt%-0.1wt% lanthanum, and the balance is copper and unavoidable impurities.

[0007] Preferably, the tin is a tin ingot with a content of ≥99.99wt%;

[0008] And / or, the silver is a silver bar with a content of ≥99.99wt%;

[0009] And / or, the zinc is a zinc ingot with a content of ≥99.9wt%;

[0010] And / or, the copper is electrolytic copper with a content of ≥99.99wt%.

[0011] The present invention also provides a method for preparing the above-mentioned copper-tin alloy heating wire, comprising: subjecting the raw materials of the above-mentioned copper-tin alloy heating wire to upward continuous casting and melting in a non-vacuum state to obtain an upper casting rod, and then subjecting the raw materials to three-roll continuous hot rolling and drawing to obtain the copper-tin alloy heating wire.

[0012] Preferably, the upward continuous casting method comprises: adding raw materials into an upward continuous casting furnace for smelting; the upward continuous casting furnace is provided with a smelting furnace and a holding furnace;

[0013] Preferably, the smelting temperature of the smelting furnace is 1160-1200°C;

[0014] And / or, the holding temperature of the holding furnace is 1140-1160° C.;

[0015] And / or, the smelting furnace and the holding furnace both use graphite flakes as covering agents;

[0016] and / or, the thickness of the covering agent in the smelting furnace is 60-120 mm;

[0017] And / or, the thickness of the covering agent in the insulation furnace is 50-100 mm;

[0018] And / or, the smelting furnace and the holding furnace are both equipped with an inert gas protection device, the gas source outlet pressure is 0.1-0.5 MPa, and the gas flow rate is 0.5-1.5 L / min;

[0019] And / or, the smelting furnace and the holding furnace both use high-purity graphite crucibles.

[0020] Preferably, the raw material input process is: firstly, copper is put into the smelting furnace, and then zinc, tin, silver and lanthanum are wrapped with a thin purple copper belt, and the covering agent on the surface of the copper liquid is removed and directly inserted into the copper liquid;

[0021] The copper is first dried before being put into the smelting furnace;

[0022] The lanthanum is prepared into a copper-lanthanum master alloy.

[0023] Preferably, the diameter of the upper lead casting rod is 16-20 mm;

[0024] And / or, the upward continuous casting speed is 650-1000 mm / min;

[0025] And / or, the pitch of the upward continuous casting is 3-5 mm;

[0026] And / or, the upward crystallizer in the upward continuous casting furnace is lined with high-purity graphite.

[0027] Preferably, the cooling circulating water in the upward continuous casting furnace is used in combination with a primary circulating cooling water system and a secondary circulating cooling water system;

[0028] Preferably, the main circulating cooling water system is a closed circulation system, which provides cooling for the upper crystallizer and the induction coil; and / or, the conductivity of the cooling water in the main circulating cooling water system is 5-30 μS / cm@25°C, and the sodium content is 0.5-3.0 mg / L; and / or, the inlet water temperature of the main circulating cooling water system is 29-31°C; and / or, the temperature difference between the inlet and outlet water of the main circulating cooling water system is 4-7°C;

[0029] Preferably, the secondary circulating cooling water system provides cooling for the heat exchanger pump in the primary circulating cooling water system; and / or the water flow rate of the secondary circulating cooling water system is 24-50m 3 / h.

[0030] Preferably, the three-roll continuous hot rolling process is: heating the upper lead casting rod to 750° C.-850° C. by online induction heating in a nitrogen atmosphere, and then performing three-roll continuous rolling to form a billet with a diameter of 2.6-3.0 mm;

[0031] And / or, the rolling speed in the three-roll continuous hot rolling is 40-50 m / min.

[0032] Preferably, the drawing process is: using a 17-die continuous drawing method to draw the blank obtained by three-roll continuous hot rolling into a heating wire with a diameter of 0.6-1.0 mm;

[0033] And / or, the drawing speed is 400-600 m / min.

[0034] The blanks obtained by three-roller continuous hot rolling in the method have no oxidation blackening, no double edges or ears, and no cracks or burrs after twisting; the surface of the blanks obtained after drawing is bright, without oxidation or peeling.

[0035] The technical solution of the present invention has the following advantages:

[0036] 1. A copper-tin alloy heating wire, the raw materials include: 1.5wt%-2.0wt% tin, 0.1wt%-0.3wt% silver, 0.03wt%-0.05wt% zinc, 0.05wt%-0.1wt% lanthanum, and the balance is copper and inevitable impurities. The invention adds silver element to the copper-tin alloy to achieve the effect of solid solution strengthening and improving the softening resistance temperature, and still has a high softening resistance temperature after processing; the addition of zinc element can narrow the crystallization temperature range, improve the fluidity of the alloy, reduce the shrinkage tendency, prevent the oxidation of copper and tin elements, purify the alloy, and reduce the tendency to generate pores; the addition of rare earth element lanthanum can purify the matrix, reduce the dendrites in the alloy structure, refine the grains, narrow the crystallization temperature range, deoxidize, degas, and reduce segregation; the invention can obtain a copper-tin alloy heating wire with high tensile strength and excellent bending resistance even when the upward continuous casting method is used through the mutual cooperation of various elements. The copper-tin alloy heating wire prepared by the invention has the advantages of high purity, fine grain structure, good high temperature resistance, stable conductivity, etc., and has a tensile strength of ≥800MPa, an oxygen content of ≤3ppm, and can be bent repeatedly without breaking for ≥10 times.

[0037] 2. A method for preparing a copper-tin alloy heating wire of the present invention uses an upper continuous casting method to prepare an upper casting rod under a non-vacuum state. The prepared upper casting rod has excellent performance and the oxygen content is stably controlled below 3ppm. The upper casting rod is then subjected to induction heating, continuous rolling with a deformation of more than 90%, and drawing to prepare a copper-tin alloy heating wire. The overall preparation process is simple and the production cost is low. The method of the present invention can produce copper-tin alloy heating wires efficiently, continuously and stably.

[0038] 3. In the preparation method of the present invention, the upward continuous casting furnace adopts a high-purity graphite crucible to replace the traditional furnace material, thereby preventing impurities in the traditional furnace material from entering the copper liquid, and increasing the inert gas protection, effectively reducing the oxygen content of the copper rod and improving the purity of the alloy.

[0039] 4. In the preparation method of the present invention, the cooling water adopts the main circulating cooling water system and the secondary circulating cooling water system. The main circulating cooling water is a closed system, and the water quality is not polluted by the external environment, which can reduce the scale in the upper crystallizer and the coil. The secondary circulating cooling water system can reduce the temperature of the main circulating cooling water system by 8-10°C, and the main circulating cooling water can withstand an inlet pressure of up to 0.95MPa, which is much higher than the inlet pressure of the circulating water in the existing upper continuous casting furnace, thereby increasing the cooling effect. At the same time, the upper crystallizer adopts graphite as the inner lining, which can reduce the gap between the copper rod and the upper crystallizer, improve the cooling effect, and effectively reduce the reverse segregation of the upper casting rod during the solidification process. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 This is a production process flow chart of the copper-tin alloy heating wire of the present invention;

[0042] Figure 2 It is a schematic structural diagram of the upward continuous casting furnace used in Examples 1-5 of the present invention;

[0043] 1-furnace body, 2-coil, 3-molten copper, 4-underflow trough, 5-partition, 6-smelting furnace, 7-holding furnace, 8-upper crystallizer, 9-water inlet, 10-water outlet, 11-heat exchanger pump, 12-secondary circulating cooling water system, 13-main circulating water tank, 14-main circulating cooling water. DETAILED DESCRIPTION

[0044] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0045] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0046] Example 1

[0047] A method for preparing a copper-tin alloy heating wire comprises the following steps:

[0048] use Figure 2 The upper continuous casting furnace shown in the figure obtains the upper casting rod, and the specific preparation process is: the raw materials are put into the smelting furnace 6 in the furnace body 1 and the coil 2 is used for heating to smelt and obtain the copper liquid 3, the material of the smelting furnace 6 is high-purity graphite, and then enters the insulation furnace 7 through the submerged flow trough 4, the smelting furnace 6 and the insulation furnace 7 are separated by the partition 5, and the upper casting rod is obtained through the upper crystallizer 8; the main circulation system provides cooling for the upper crystallizer 8, and the specific process is: the main circulation cooling water 14 in the main circulation water tank 13 flows through the upper crystallizer 8 through the water inlet 9, and then through the water outlet 10, thereby providing cooling for the upper crystallizer, and at the same time, the secondary circulation cooling water system 12 is used to provide cooling for the main circulation cooling water system through the heat exchanger pump 11.

[0049] 1) Upward continuous casting: Weigh 1.5wt% tin, 0.1wt% silver, 0.03wt% zinc, 0.05wt% rare earth lanthanum, and the balance is copper, and put the raw materials into an upward continuous casting furnace for smelting to obtain an upward casting rod. The smelting furnace temperature in the upward continuous casting furnace is 1160°C, the thickness of the covering agent in the smelting furnace is 60mm, the temperature of the insulation furnace in the upward continuous casting furnace is 1140°C, the thickness of the covering agent in the insulation furnace is 50mm, the gas source outlet pressure of the inert gas protection device on the smelting furnace and the insulation furnace is 0.1MPa, the gas flow rate is 0.5L / min, the diameter of the upper casting rod is 20mm, the speed is 750mm / min, the pitch of the upward continuous casting is 3mm, the pressure of the cooling circulation water of the upper crystallizer is 0.95MPa, the inlet temperature of the main circulating water cooling water system is 29°C, the temperature difference between the inlet and outlet water of the main circulating cooling water system is 5°C, and the secondary circulating water flow rate is 50m 3 / h;

[0050] 2) three-roll continuous hot rolling: the upper lead casting rod is heated to 850° C. by online induction heating, and nitrogen is filled for protection at the same time, and then the upper lead casting rod prepared in step 1) is rolled into a billet with a diameter of 3.0 mm by a continuous rolling unit, and the rolling speed is 40 m / min;

[0051] 3) Drawing: The blank obtained in step 2) is drawn into a copper-tin alloy heating wire with a diameter of 1.0 mm by a 17-die continuous drawing method at a drawing speed of 500 m / min.

[0052] The tensile strength of the prepared copper-tin alloy heating wire was tested by an electronic tensile testing machine; referring to the determination method of softening temperature in the national standard GB / T 33370-2016, different temperature gradients were set, and the copper-tin alloy heating wires were kept warm for 1 hour at different temperatures and then taken out of the furnace, cooled naturally to room temperature, and the hardness was tested by a Vickers hardness tester. The holding temperature at which the value dropped to 80% of the original hardness was the softening temperature; referring to the repeated bending test method in GB / T 238-2013, a bending tester was used to test the bending resistance; and a DC digital resistance tester was used to test the conductivity. After testing, the tensile strength of the copper-tin alloy heating wire prepared in this embodiment was 805MPa, the softening temperature was 370℃, the number of repeated bendings without breaking was 13 times, the conductivity was 47%IACS, and the oxygen content was 2.6ppm.

[0053] Example 2

[0054] A method for preparing a copper-tin alloy heating wire comprises the following steps:

[0055] 1) Upward continuous casting: Weigh 1.8wt% tin, 0.3wt% silver, 0.05wt% zinc, 0.1wt% rare earth lanthanum, and the balance copper, and put the raw materials into an upward continuous casting furnace for smelting to obtain an upward casting rod. The smelting furnace temperature in the upward continuous casting furnace is 1180°C, the thickness of the covering agent in the smelting furnace is 90mm, the temperature of the insulation furnace in the upward continuous casting furnace is 1150°C, the thickness of the covering agent in the insulation furnace is 75mm, the gas source outlet pressure of the inert gas protection device on the smelting furnace and the insulation furnace is 0.3MPa, the gas flow rate is 1.0L / min, the diameter of the upper casting rod is 16mm, the speed is 1000mm / min, the pitch of the upward continuous casting is 3mm, the pressure of the cooling circulating water of the upper crystallizer is 0.90MPa, the inlet temperature of the main circulating water cooling water system is 29°C, the temperature difference between the inlet and outlet water of the main circulating cooling water system is 5°C, and the secondary circulating water flow rate is 24m 3 / h;

[0056] 2) three-roll continuous hot rolling: using online induction heating to heat the upper lead casting rod to 800° C., while filling with nitrogen for protection, and then using a continuous rolling unit to roll the upper lead casting rod obtained in step 1) into a billet with a diameter of 2.6 mm, at a rolling speed of 50 m / min;

[0057] 3) Drawing: The blank obtained in step 2) is drawn into a copper-tin alloy heating wire with a diameter of 0.8 mm by a 17-die continuous drawing method at a drawing speed of 550 m / min.

[0058] The performance of the copper-tin alloy heating wire prepared in this embodiment was tested by the same method as in Example 1. After testing, the copper-tin alloy heating wire prepared in this embodiment had a tensile strength of 815 MPa, a softening temperature of 390°C, 13 repeated bends without breaking, a conductivity of 45% IACS, and an oxygen content of 2.5 ppm.

[0059] Example 3

[0060] A method for preparing a copper-tin alloy heating wire comprises the following steps:

[0061] 1) Upward continuous casting: Weigh 2.0wt% tin, 0.3wt% silver, 0.05wt% zinc, 0.1wt% rare earth lanthanum, and the balance is copper, and put the raw materials into an upward continuous casting furnace for smelting to obtain an upward casting rod. The smelting furnace temperature in the upward continuous casting furnace is 1190°C, the thickness of the covering agent in the smelting furnace is 100mm, the temperature of the insulation furnace in the upward continuous casting furnace is 1160°C, the thickness of the covering agent in the insulation furnace is 100mm, the gas source outlet pressure of the inert gas protection device on the smelting furnace and the insulation furnace is 0.4MPa, the gas flow rate is 1.5L / min, the diameter of the upper casting rod is 16mm, the speed is 900mm / min, the pitch of the upward continuous casting is 3mm, the pressure of the cooling circulation water of the upper crystallizer is 0.90MPa, the inlet water temperature of the main circulating water cooling water system is 29°C, the temperature difference between the inlet and outlet water of the main circulating cooling water system is 5°C, and the secondary circulating water flow rate is 37m 3 / h;

[0062] 2) three-roll continuous hot rolling: using online induction heating to heat the upper lead casting rod to 820° C., while filling with nitrogen for protection, and then using a continuous rolling unit to roll the upper lead casting rod obtained in step 1) into a billet with a diameter of 2.6 mm, at a rolling speed of 50 m / min;

[0063] 3) Drawing: The blank obtained in step 2) is drawn into a copper-tin alloy heating wire with a diameter of 0.8 mm by a 17-die continuous drawing method at a drawing speed of 550 m / min.

[0064] The performance of the copper-tin alloy heating wire prepared in this embodiment was tested by the same method as in Example 1. After testing, the copper-tin alloy heating wire prepared in this embodiment had a tensile strength of 820 MPa, a softening temperature of 385°C, 15 repeated bends without breaking, a conductivity of 43% IACS, and an oxygen content of 2.7 ppm.

[0065] Example 4

[0066] A method for preparing a copper-tin alloy heating wire comprises the following steps:

[0067] 1) Upward continuous casting: Weigh 1.5wt% tin, 0.1wt% silver, 0.03wt% zinc, 0.05wt% rare earth lanthanum, and the balance is copper, and put the raw materials into an upward continuous casting furnace for smelting to obtain an upward casting rod. The temperature of the smelting furnace in the upward continuous casting furnace is 1160°C, the thickness of the covering agent in the smelting furnace is 60mm, the temperature of the insulation furnace in the upward continuous casting furnace is 1140°C, the thickness of the covering agent in the insulation furnace is 50mm, the gas source outlet pressure of the inert gas protection device on the smelting furnace and the insulation furnace is 0.1MPa, the gas flow rate is 0.5L / min, the diameter of the upper casting rod is 16mm, the speed is 1000mm / min, the pitch of the upward continuous casting is 5mm, the pressure of the cooling circulating water of the upper crystallizer is 0.95MPa, the inlet temperature of the main circulating water cooling water system is 29°C, the temperature difference between the inlet and outlet water of the main circulating cooling water system is 4°C, and the secondary circulating water flow rate is 24m 3 / h;

[0068] 2) three-roll continuous hot rolling: the upper lead casting rod is heated to 750° C. by online induction heating, and nitrogen is filled for protection at the same time, and then the upper lead casting rod prepared in step 1) is rolled into a billet with a diameter of 2.6 mm by a continuous rolling unit, and the rolling speed is 40 m / min;

[0069] 3) Drawing: The blank obtained in step 2) is drawn into a copper-tin alloy heating wire with a diameter of 0.6 mm by a 17-die continuous drawing method at a drawing speed of 400 m / min.

[0070] The performance of the copper-tin alloy heating wire prepared in this embodiment was tested by the same method as in Example 1. After testing, the copper-tin alloy heating wire prepared in this embodiment had a tensile strength of 807 MPa, a softening temperature of 370°C, 14 repeated bends without breaking, a conductivity of 47% IACS, and an oxygen content of 2.7 ppm.

[0071] Example 5

[0072] A method for preparing a copper-tin alloy heating wire comprises the following steps:

[0073] 1) Upward continuous casting: Weigh 2.0wt% tin, 0.3wt% silver, 0.05wt% zinc, 0.1wt% rare earth lanthanum, and the balance copper, and put the raw materials into an upward continuous casting furnace for smelting to obtain an upward casting rod. The smelting furnace temperature in the upward continuous casting furnace is 1200°C, the thickness of the covering agent in the smelting furnace is 120mm, the temperature of the insulation furnace in the upward continuous casting furnace is 1160°C, the thickness of the covering agent in the insulation furnace is 100mm, the gas source outlet pressure of the inert gas protection device on the smelting furnace and the insulation furnace is 0.5MPa, the gas flow rate is 1.5L / min, the diameter of the upper casting rod is 20mm, the speed is 650mm / min, the pitch of the upward continuous casting is 3mm, the pressure of the cooling circulation water of the upper crystallizer is 0.95MPa, the inlet water temperature of the main circulating water cooling water system is 31°C, the temperature difference between the inlet and outlet water of the main circulating cooling water system is 7°C, and the secondary circulating water flow rate is 50m 3 / h;

[0074] 2) three-roll continuous hot rolling: the upper lead casting rod is heated to 850° C. by online induction heating, and nitrogen is filled for protection at the same time, and then the upper lead casting rod prepared in step 1) is rolled into a billet with a diameter of 3.0 mm by a continuous rolling unit, and the rolling speed is 50 m / min;

[0075] 3) Drawing: The blank obtained in step 2) is drawn into a copper-tin alloy heating wire with a diameter of 1.0 mm by a 17-die continuous drawing method, and the drawing speed is 600 m / min.

[0076] The performance of the copper-tin alloy heating wire prepared in this embodiment was tested by the same method as in Example 1. After testing, the copper-tin alloy heating wire prepared in this embodiment had a tensile strength of 817 MPa, a softening temperature of 385°C, 15 repeated bends without breaking, a conductivity of 44% IACS, and an oxygen content of 2.5 ppm.

[0077] Comparative Example 1

[0078] The difference between this comparative example and Example 1 is that silver, zinc and rare earth lanthanum are not added, and the other parts are the same as Example 1.

[0079] The performance of the copper-tin alloy heating wire prepared in this comparative example was tested by the same method as in Example 1. After testing, the copper-tin alloy heating wire prepared in this comparative example had a tensile strength of 790 MPa, a softening temperature of 340°C, 8 repeated bends without breaking, a conductivity of 48% IACS, and an oxygen content of 2.6 ppm.

[0080] According to the test results of Examples 1-5 and Comparative Example 1, the copper-tin alloy heating wire prepared in Comparative Example 1 can be bent repeatedly without breaking for less than 10 times, and its bending resistance is poor. The copper-tin alloy heating wires prepared in Examples 1-5 of the present invention have a tensile strength of ≥800 MPa, an oxygen content of ≤3 ppm, can be bent repeatedly without breaking for ≥10 times, have stable electrical conductivity and good high temperature resistance.

[0081] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for preparing a copper-tin alloy heating wire, characterized in that: The raw materials of the copper-tin alloy heating wire are composed of: 1.5 wt%-2.0 wt% of tin, 0.1 wt%-0.3 wt% of silver, 0.03 wt%-0.05 wt% of zinc, 0.05 wt%-0.1 wt% of lanthanum, and the balance is copper and unavoidable impurities; The raw materials are subjected to upward continuous casting and smelting in a non-vacuum state to obtain an upper casting rod, and then subjected to three-roller continuous hot rolling and drawing to obtain a copper-tin alloy heating wire; The cooling circulating water in the upward continuous casting furnace adopts a main circulating cooling water system and a secondary circulating cooling water system in combination; the secondary circulating cooling water system provides cooling for the heat exchanger pump in the main circulating cooling water system.

2. The method for preparing a copper-tin alloy heating wire according to claim 1, characterized in that: The tin is a tin ingot with a content of ≥99.99 wt%; and / or, the silver is a silver bar having a content of ≥ 99.99 wt%; And / or, the zinc is a zinc ingot having a content of ≥99.9 wt%; And / or, the copper is electrolytic copper with a content of ≥99.99 wt%.

3. The preparation method according to claim 1, characterized in that: The upward continuous casting method comprises: adding raw materials into an upward continuous casting furnace for smelting; the upward continuous casting furnace is provided with a smelting furnace and a heat preservation furnace.

4. The preparation method according to claim 3, characterized in that: The smelting temperature of the smelting furnace is 1160-1200°C; And / or, the holding temperature of the holding furnace is 1140-1160° C.; And / or, the smelting furnace and the holding furnace both use graphite flakes as covering agents; and / or, the thickness of the covering agent in the smelting furnace is 60-120 mm; And / or, the thickness of the covering agent in the holding furnace is 50-100 mm; And / or, the smelting furnace and the holding furnace are both equipped with an inert gas protection device, the gas source outlet pressure is 0.1-0.5 MPa, and the gas flow rate is 0.5-1.5 L / min; And / or, the smelting furnace and the holding furnace both use high-purity graphite crucibles.

5. The preparation method according to claim 3 or 4, characterized in that: The raw material input process is as follows: firstly, copper is put into the smelting furnace, then zinc, tin, silver and lanthanum are wrapped with a thin purple copper belt, and the covering agent on the surface of the copper liquid is removed and directly inserted into the copper liquid; The copper is first dried before being put into the smelting furnace; The lanthanum is prepared into a copper-lanthanum master alloy.

6. The preparation method according to claim 1, characterized in that: The diameter of the upper lead casting rod is 16-20 mm; And / or, the upward continuous casting speed is 650-1000 mm / min; And / or, the pitch of the upward continuous casting is 3-5 mm.

7. The preparation method according to claim 3, characterized in that: The upward crystallizer in the upward continuous casting furnace is lined with high-purity graphite.

8. The preparation method according to claim 1, characterized in that: The main circulating cooling water system is a closed circulation system, which provides cooling for the upper crystallizer and the induction coil; and / or, the conductivity of the cooling water in the main circulating cooling water system at 25°C is 5-30 µS / cm, and the sodium content is 0.5-3.0 mg / L; and / or, the inlet water temperature of the main circulating cooling water system is 29-31°C; and / or, the temperature difference between the inlet and outlet water of the main circulating cooling water system is 4-7°C.

9. The preparation method according to claim 1, characterized in that: The water flow rate of the secondary circulating cooling water system is 24-50 m 3 / h.

10. The preparation method according to claim 1, characterized in that: The three-roll continuous hot rolling process is as follows: the upper lead casting rod is heated to 750° C.-850° C. by online induction heating in a nitrogen atmosphere, and then three-roll continuous rolling is performed to form a billet with a diameter of 2.6-3.0 mm; And / or, the rolling speed in the three-roll continuous hot rolling is 40-50 m / min.

11. The preparation method according to claim 1, characterized in that: The drawing process is as follows: the blank obtained by three-roll continuous hot rolling is drawn into a heating wire with a diameter of 0.6-1.0 mm by a 17-die continuous drawing method; And / or, the drawing speed is 400-600 m / min.

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