Bright annealing process for copper alloy wire

Abstract

The invention discloses a bright annealing process for a copper alloy wire. The bright annealing process comprises the following steps: coating the surface of the copper alloy wire with a composite solid lubricant; the heating / cooling rate of a preheating zone (200-350 DEG C), the heating / cooling rate of a main annealing zone (450-650 DEG C) and the heating / cooling rate of a slow cooling zone (300-450 DEG C) are smaller than or equal to 15 DEG C / s; and an atomized anti-oxidation liquid film is applied to an outlet of the slow cooling area. According to the bright annealing process for the copper alloy wire, the lubricant with specific components is decomposed at a high temperature to form an in-situ protection layer, generation of oxide skin is inhibited in combination with gradient temperature control, and a bright surface with the surface roughness Ra smaller than or equal to 0.2 micron can be achieved without introducing hydrogen or nitrogen. The cost is reduced by more than 40%, and the method is suitable for easily-oxidized copper alloys such as tin-phosphor bronze and cupronickel.

Description

Technical Field

[0001] This invention relates to the field of copper alloy wire technology, specifically a bright annealing process for copper alloy wire. Background Technology

[0002] Copper alloys are alloys composed of pure copper as the base material and one or more other elements added. Pure copper is reddish-purple and is also known as red copper. Commonly used copper alloys are divided into three main categories: brass, bronze, and cupronickel.

[0003] The following problems exist with existing copper alloy wires during annealing:

[0004] I. Oxidation control is costly.

[0005] Traditional hydrogen / nitrogen protected annealing requires a continuous supply of high-purity gas, which increases costs.

[0006] II. Surface quality does not meet standards

[0007] When annealed without a protective atmosphere, copper alloys oxidize rapidly above 400°C (oxidation weight gain > 2 mg / cm³). 2 This results in the formation of Cu2O / CuO black spots on the surface, and the roughness Ra deteriorates to 0.8-1.5 μm;

[0008] III. Poor process adaptability

[0009] Existing solid coatings (such as borax glass powder) crack and peel off during the slow cooling stage, failing to cover the entire process. Furthermore, traditional lubricants decompose and fail in high-temperature zones (>600℃) (such as paraffin wax, which completely vaporizes at 450℃). Summary of the Invention

[0010] The purpose of this invention is to provide a bright annealing process for copper alloy wires in order to solve the problems mentioned above.

[0011] To achieve the above objectives, the present invention provides the following technical solution: a bright annealing process for copper alloy wire, comprising the following steps:

[0012] (a) A composite solid lubricant is uniformly coated on the surface of the copper alloy wire, with a coating thickness of 0.5-3 μm;

[0013] (b) The coated wire is fed into a continuous annealing apparatus and passes through the preheating zone, the main annealing zone and the slow cooling zone in sequence.

[0014] (c) The temperature of the preheating zone is 200-350℃, and the heating rate is ≤10℃ / s;

[0015] (d) Main annealing zone temperature 450-650℃, holding time 10-120s;

[0016] (e) Slow cooling zone temperature 300-450℃, cooling rate ≤15℃ / s;

[0017] (f) When the wire leaves the slow cooling zone, spray atomized antioxidant liquid on its surface.

[0018] Preferably, the composite solid lubricant comprises the following components by mass percentage:

[0019] Chlorinated paraffin 40-60%, zinc stearate 20-30%, nano alumina 5-15%, organosilicon resin 10-20%.

[0020] Preferably, the nano-alumina has a particle size of 20-50 nm and is surface-modified with a silane coupling agent in the lubricant.

[0021] Preferably, the temperature control of the main annealing zone is a multi-stage gradient heating method:

[0022] The first stage is 450-500℃ (10-30s), the second stage is 520-580℃ (20-60s), and the third stage is 600-650℃ (10-30s).

[0023] Preferably, the atomized antioxidant liquid is a water-soluble organic amine compound solution with a concentration of 5-15 wt% and an atomized particle size ≤10 μm.

[0024] Preferably, the copper alloy wire is tin-phosphor bronze, cupronickel, or copper-nickel-silicon alloy, with a wire diameter ranging from 0.05 to 2.0 mm.

[0025] Preferably, the oxygen increase on the surface of the annealed wire is ≤0.3 mg / cm². 2 Surface roughness Ra≤0.2μm.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The bright annealing process for this copper alloy wire utilizes a lubricant with specific components to decompose at high temperatures, forming an in-situ protective layer. Combined with gradient temperature control to suppress oxide scale formation, a bright surface with a surface roughness Ra≤0.2μm can be achieved without the introduction of hydrogen or nitrogen. This invention reduces costs by more than 40% and is applicable to easily oxidized copper alloys such as tin-phosphor bronze and cupronickel. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1:

[0030] A bright annealing process for copper alloy wire is described below, detailing its production and application:

[0031] (a) A composite solid lubricant is uniformly coated on the surface of the copper alloy wire, with a coating thickness of 0.5-3 μm;

[0032] (b) The coated wire is fed into a continuous annealing apparatus and passes through the preheating zone, the main annealing zone and the slow cooling zone in sequence.

[0033] (c) The temperature of the preheating zone is 200-350℃, and the heating rate is ≤10℃ / s;

[0034] (d) Main annealing zone temperature 450-650℃, holding time 10-120s;

[0035] (e) Slow cooling zone temperature 300-450℃, cooling rate ≤15℃ / s;

[0036] (f) When the wire leaves the slow cooling zone, spray atomized antioxidant liquid on its surface.

[0037] Furthermore, the composite solid lubricant comprises the following components in weight percentages:

[0038] Chlorinated paraffin 40-60%, zinc stearate 20-30%, nano alumina 5-15%, organosilicon resin 10-20%.

[0039] Furthermore, the nano-alumina has a particle size of 20-50 nm and is surface-modified in the lubricant using a silane coupling agent.

[0040] Furthermore, the temperature control of the main annealing zone is a multi-stage gradient heating:

[0041] The first stage is 450-500℃ (10-30s), the second stage is 520-580℃ (20-60s), and the third stage is 600-650℃ (10-30s).

[0042] Furthermore, the atomized antioxidant liquid is a water-soluble organic amine compound solution with a concentration of 5-15 wt% and an atomized particle size ≤10 μm.

[0043] Furthermore, the copper alloy wire is tin-phosphor bronze, cupronickel, or copper-nickel-silicon alloy, with a wire diameter ranging from 0.05 to 2.0 mm.

[0044] Furthermore, the oxygen increase on the surface of the annealed wire is ≤0.3 mg / cm³. 2 Surface roughness Ra≤0.2μm.

[0045] Example 2:

[0046] A bright annealing process for copper alloy wire is described below, detailing its production and application:

[0047] C5191 tin-phosphor bronze wire with a diameter of 0.3mm:

[0048] Lubricant formulation: 55% chlorinated paraffin + 25% zinc stearate + 8% nano alumina (30nm) + 12% silicone resin;

[0049] Annealing parameters:

[0050] Preheating zone: 280℃ / 15s (heating rate 8℃ / s);

[0051] Main annealing zone: 480℃ (20s) → 550℃ (40s) → 620℃ (15s);

[0052] Slow cooling zone: 380℃ / 20s (cooling rate 12℃ / s);

[0053] Antioxidant solution: 10wt% ethanolamine aqueous solution;

[0054] Results: The surface is mirror-like and glossy, Ra = 0.15 μm, tensile strength deviation ≤ 3%, and conductivity increased by 5%.

[0055] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0056] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A bright annealing process for copper alloy wire, characterized in that, Includes the following steps: (a) A composite solid lubricant is uniformly coated on the surface of the copper alloy wire, with a coating thickness of 0.5-3 μm; (b) The coated wire is fed into a continuous annealing apparatus and passes through the preheating zone, the main annealing zone and the slow cooling zone in sequence. (c) The temperature of the preheating zone is 200-350℃, and the heating rate is ≤10℃ / s; (d) Main annealing zone temperature 450-650℃, holding time 10-120s; (e) Slow cooling zone temperature 300-450℃, cooling rate ≤15℃ / s; (f) When the wire leaves the slow cooling zone, spray atomized antioxidant liquid on its surface.

2. The bright annealing process for copper alloy wire according to claim 1, characterized in that: The composite solid lubricant comprises the following components by mass percentage: Chlorinated paraffin 40-60%, zinc stearate 20-30%, nano alumina 5-15%, organosilicon resin 10-20%.

3. The bright annealing process for copper alloy wire according to claim 2, characterized in that: The nano-alumina has a particle size of 20-50 nm and is surface-modified with a silane coupling agent in the lubricant.

4. The bright annealing process for copper alloy wire according to claim 1, characterized in that: The temperature control in the main annealing zone is achieved through multi-stage gradient heating. The first stage is 450-500℃ (10-30s), the second stage is 520-580℃ (20-60s), and the third stage is 600-650℃ (10-30s).

5. The bright annealing process for copper alloy wire according to claim 1, characterized in that: The atomized antioxidant liquid is a water-soluble organic amine compound solution with a concentration of 5-15 wt% and an atomized particle size of ≤10 μm.

6. The bright annealing process for copper alloy wire according to claim 1, characterized in that: The copper alloy wire is made of tin-phosphor bronze, cupronickel, or copper-nickel-silicon alloy, with a wire diameter ranging from 0.05 to 2.0 mm.

7. The bright annealing process for copper alloy wire according to claim 1, characterized in that: The oxygen increase on the surface of the annealed wire is ≤0.3 mg / cm³. 2 Surface roughness Ra≤0.2μm.