Processing technology of T-shaped copper conductor for energy-saving high-voltage cable

Abstract

The invention discloses a processing technology of a T-shaped copper conductor for an energy-saving high-voltage cable. The processing technology comprises the steps of high-purity copper rod pretreatment, multi-pass low-temperature drawing, gradient magnetic field annealing, T-shaped section precision forming and surface nanocrystallization treatment. By controlling the drawing accumulated deformation amount to be 60%-70% and combining two-stage annealing of an axial static magnetic field (0.3-0.8 T) and a rotating alternating magnetic field (1.0-1.5 T), grain ultra-fining (ASTM 12 level) is achieved under nitrogen protection. The final conductor conductivity is greater than or equal to 101% IACS, the processing energy consumption is reduced by more than 30%, the edge arc radius R is greater than or equal to 0.3 mm, and the method is suitable for 550kV high-voltage cables.

Description

Technical Field

[0001] The invention relates to the technical field of T-shaped copper conductors, in particular to a processing technology for T-shaped copper conductors for energy-saving high-voltage cables. Background Art

[0002] Copper conductor is a term in electromechanical engineering, used for fire-resistant layer, insulation, sheath, filling. It is widely used in various fields, including high-voltage cables. However, when processing T-shaped copper conductors for high-voltage cables, the following problems exist:

[0003] T-shaped copper conductors are conventionally formed by twisting multiple strands or welding them together, which can lead to problems such as uneven resistance and easy oxidation of joints, resulting in increased energy consumption.

[0004] The cold drawing + annealing process has high energy consumption, and grain coarsening during annealing affects electrical conductivity (conventional IACS ≤ 99%).

[0005] Surface roughness (Ra>0.8μm) leads to reduced adhesion of cable insulation and increased risk of partial discharge. Summary of the Invention

[0006] The object of the present invention is to provide a process for processing an energy-saving T-shaped copper conductor for a high-voltage cable, so as to solve the above-mentioned problems of the process for processing an energy-saving T-shaped copper conductor for a high-voltage cable on the market today.

[0007] To achieve the above object, the present invention provides the following technical solution: a process for processing a T-shaped copper conductor for an energy-saving high-voltage cable, comprising the following steps:

[0008] S1. Pretreatment of high-purity copper rod: Use electrolytic copper rod with oxygen content ≤ 5ppm and perform ultrasonic-alkaline cleaning;

[0009] S2. Multi-pass low-temperature drawing: 4 to 6 passes, with a single-pass compression rate of 15% to 18%, and cooling temperature control ≤ 40°C;

[0010] S3. Gradient magnetic field annealing: Under nitrogen protection, first anneal in an axial static magnetic field at 250°C, then in a rotating alternating magnetic field at 400°C;

[0011] S4. T-section precision forming: cold rolled to the designed size by a four-roll servo rolling mill;

[0012] S5. Surface nano-treatment: Micro-arc oxidation to form a Cu2O / CuO composite layer.

[0013] Preferably, in the gradient magnetic field annealing in step S3, the axial static magnetic field strength is 0.3-0.8 T, the rotating alternating magnetic field strength is 1.0-1.5 T, and the frequency is 40-60 Hz.

[0014] Preferably, the cumulative deformation during drawing in step S2 is 60% to 70%, and the final drawing speed is ≤5 m / min.

[0015] Preferably, after the surface nano-processing in step S5, the roughness Ra is less than or equal to 0.3 μm, and the thickness of the oxide layer is 2 to 8 μm.

[0016] Preferably, after forming in step S4, the arc radius R of the edge of the T-shaped conductor is ≥0.3 mm.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) Energy saving: Gradient magnetic field annealing shortens process time by 40%, and the comprehensive energy consumption is ≤85kWh / t.

[0019] (2) High conductivity: dislocation density reduced to 10 9 / cm 2 , conductivity 101.5% IACS.

[0020] (3) Reliability: The grain size difference at the T-shaped corner is ≤0.5μm, and the fatigue life is increased by 3 times.

[0021] (4) Compatibility: Applicable to 120~550kV high voltage cable conductors (cross section 800~2500mm 2 ). DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0023] Example 1:

[0024] A processing technology for T-shaped copper conductors for energy-saving high-voltage cables. The following is a detailed introduction to the above production and its application:

[0025] S1. Pretreatment of high-purity copper rod: Use electrolytic copper rod with oxygen content ≤ 5ppm and perform ultrasonic-alkaline cleaning;

[0026] S2. Multi-pass low-temperature drawing: 4-pass drawing, single-pass compression rate 15%, cooling temperature control ≤ 40°C;

[0027] S3. Gradient magnetic field annealing: Under nitrogen protection, first anneal in an axial static magnetic field at 250°C, then in a rotating alternating magnetic field at 400°C;

[0028] S4. T-section precision forming: cold rolled to the designed size by a four-roll servo rolling mill;

[0029] S5. Surface nano-treatment: Micro-arc oxidation to form a Cu2O / CuO composite layer.

[0030] Preferably, in the gradient magnetic field annealing in step S3, the axial static magnetic field intensity is 0.3 T, the rotating alternating magnetic field intensity is 1.0 T, and the frequency is 40 Hz.

[0031] Preferably, the cumulative deformation of the drawing in step S2 is 60%, and the final drawing speed is ≤5m / min.

[0032] Preferably, after the surface nano-processing in step S5, the roughness Ra is less than or equal to 0.3 μm, and the thickness of the oxide layer is 2 μm.

[0033] Preferably, after forming in step S4, the arc radius R of the edge of the T-shaped conductor is ≥0.3 mm.

[0034] Example 2:

[0035] A processing technology for T-shaped copper conductors for energy-saving high-voltage cables. The following is a detailed introduction to the above production and its application:

[0036] S1. Pretreatment of high-purity copper rod: Use electrolytic copper rod with oxygen content ≤ 5ppm and perform ultrasonic-alkaline cleaning;

[0037] S2. Multi-pass low-temperature drawing: 6-pass drawing, single-pass compression ratio 118%, cooling temperature ≤ 40°C;

[0038] S3. Gradient magnetic field annealing: Under nitrogen protection, first anneal in an axial static magnetic field at 250°C, then in a rotating alternating magnetic field at 400°C;

[0039] S4. T-section precision forming: cold rolled to the designed size by a four-roll servo rolling mill;

[0040] S5. Surface nano-treatment: Micro-arc oxidation to form a Cu2O / CuO composite layer.

[0041] Preferably, in the gradient magnetic field annealing in step S3, the axial static magnetic field strength is 0.8 T, the rotating alternating magnetic field strength is 1.5 T, and the frequency is 60 Hz.

[0042] Preferably, the cumulative deformation of the drawing in step S2 is 70%, and the final drawing speed is ≤5m / min.

[0043] Preferably, after the surface nano-processing in step S5, the roughness Ra is less than or equal to 0.3 μm, and the thickness of the oxide layer is 8 μm.

[0044] Preferably, after forming in step S4, the arc radius R of the edge of the T-shaped conductor is ≥0.3 mm.

[0045] 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.

[0046] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A process for processing T-shaped copper conductors for energy-saving high-voltage cables, characterized in that: The following steps are involved: S1. Pretreatment of high-purity copper rod: Use electrolytic copper rod with oxygen content ≤ 5ppm and perform ultrasonic-alkaline cleaning; S2. Multi-pass low-temperature drawing: 4 to 6 passes, with a single-pass compression rate of 15% to 18%, and cooling temperature control ≤ 40°C; S3. Gradient magnetic field annealing: Under nitrogen protection, first anneal in an axial static magnetic field at 250°C, then in a rotating alternating magnetic field at 400°C; S4. T-section precision forming: cold rolled to the designed size by a four-roll servo rolling mill; S5. Surface nano-treatment: Micro-arc oxidation to form a Cu2O / CuO composite layer.

2. The process for processing a T-shaped copper conductor for an energy-saving high-voltage cable according to claim 1, characterized in that: In the gradient magnetic field annealing step S3, the axial static magnetic field strength is 0.3-0.8 T, the rotating alternating magnetic field strength is 1.0-1.5 T, and the frequency is 40-60 Hz.

3. The process for processing a T-shaped copper conductor for an energy-saving high-voltage cable according to claim 1, characterized in that: The cumulative deformation during drawing in step S2 is 60% to 70%, and the final drawing speed is ≤5 m / min.

4. The process for processing a T-shaped copper conductor for an energy-saving high-voltage cable according to claim 1, characterized in that: After the surface nano-processing in step S5, the roughness Ra is less than or equal to 0.3 μm, and the thickness of the oxide layer is 2 to 8 μm.

5. The process for processing a T-shaped copper conductor for an energy-saving high-voltage cable according to claim 1, characterized in that: After forming in step S4, the arc radius R of the edge of the T-shaped conductor is greater than or equal to 0.3 mm.