Process for processing small diameter zirconium wire

Abstract

The present application relates to the field of small-diameter zirconium wire manufacturing, and particularly relates to a processing technology of small-diameter zirconium wire, which processes 6mm-diameter pure zirconium rod into 2mm-diameter zirconium wire, accurately controls the reduction and deformation rate of each pass based on setting four rolling processes, the single-pass deformation is less than 12%, and the total deformation rate of each rolling process is less than 45%; and a reasonable vacuum heat treatment process is supplemented after each rolling process, the vacuum heat treatment is performed at a heat treatment temperature of 780±20 DEG C, the heat preservation is performed for 1h, and then cooling is performed, the vacuum degree is 10-3MPa; and then the small-diameter zirconium wire meeting the market requirements is produced, the yield strength of the finished zirconium wire is greater than 460MPa, the tensile strength is greater than 500MPa, and the elongation is greater than 5%. The present application not only does not need to use a coating to protect the zirconium wire, but also can avoid using an acid pickling process.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of small-diameter zirconium wire manufacturing, in particular to a processing technology of small-diameter zirconium wire. BACKGROUND

[0002] Metal wire materials are increasingly widely used in people's daily life and work, and with the continuous acceleration of China's social economy, the application demand for rare metal wire materials is also increasing. At present, the market demand for rare metal wire materials such as titanium wire and zirconium wire is increasing.

[0003] With the rapid development of emerging materials and the increasing demand for nuclear energy applications, the zirconium industry is entering a golden period of investment. As an important rare metal, zirconium has amazing corrosion resistance, extremely high melting point, outstanding nuclear performance, and excellent electrical conductivity, and can be widely used in electronic component manufacturing and electronic industry, and can be used as a grid support, cathode support and grid material, and as an electrode head for air plasma cutting machine.

[0004] However, zirconium has super-high hardness and strength, and poor toughness, and it is difficult to process pure zirconium wire rod into 2mm small-diameter zirconium wire through traditional cold rolling.

[0005] The production difficulty of small-diameter zirconium wire lies in: 1. High precision requirement: since the diameter of zirconium wire is very small, the surface quality and dimensional accuracy are very high, and special process and equipment are needed to ensure high-precision processing; 2. Insufficient strength: small-diameter zirconium wire is prone to breakage due to insufficient strength of the material itself, so special process is needed to ensure its strength and toughness during processing; 3. Difficult material processing: as mentioned above, zirconium is a high-strength and high-hardness metal, which is difficult to process.

[0006] At present, there are few documents on the production process of small-diameter zirconium wire. The Chinese patent with application number CN201310561940 discloses a low-loss zirconium wire processing technology, which adopts the process of ingot melting, cogging, forging, rolling wire rod, grinding, coating protection, annealing, drawing, pickling or polishing, and vacuum annealing. The deformation amount of each drawing in the initial period of the processing amount is more than 10%, and the deformation amount of each time is kept at 0.1mm when the diameter is less than 1mm. However, no more detailed rolling process is disclosed, and the above-mentioned zirconium wire raw material needs to be wrapped with latex paint before rolling to prevent oxidation, and finally uses an acid washing process, which increases the cost and easily causes environmental pollution. SUMMARY

[0007] In order to solve the above technical problems in the prior art, the present application aims to provide a processing technology of small-diameter zirconium wire, which shortens the production cycle, avoids pickling process and environmental pollution by formulating the rolling and heat treatment process of the zirconium wire and producing the zirconium wire meeting the market requirements.

[0008] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0009] A processing technology of small-diameter zirconium wire, which comprises the following steps:

[0010] 1) Material preparation: prepare pure zirconium wire rod as raw material;

[0011] 2) Vacuum heat treatment of the raw material, heat treatment temperature 780±20℃, heat preservation for 1h and then cooling, vacuum degree 10 -3 MPa;

[0012] 3) Raw material rolling - first rolling range: the rolling range is divided into five passes, and the total deformation is 44.75%; the deformation of the first pass is 10.76%-11.51%; the deformation of the second pass is 11.55%-11.67%; the deformation of the third pass is 11.51%-11.69%; the deformation of the fourth pass is 10.76%-11.66%; and the deformation of the fifth pass is 9.57%-10.64%;

[0013] 4) First vacuum heat treatment of the semi-finished product: heat treatment temperature 780±20℃, heat preservation for 1h and then cooling, vacuum degree 10 - 3 MPa;

[0014] 5) Semi-finished product rolling - second rolling range: the rolling range is divided into five passes, and the total deformation is 44.59%; the deformation of the first pass is 10.81%-11.74%; the deformation of the second pass is 11.17%-11.70%; the deformation of the third pass is:

[0015] 11.26%-11.39%; the deformation of the fourth pass is 11.16%-11.42%; and the deformation of the fifth pass is

[0016] 9.82%-10.64%;

[0017] 6) Second vacuum heat treatment of the semi-finished product: heat treatment temperature 780±20℃, heat preservation for 1h and then cooling, vacuum degree 10 - 3 MPa;

[0018] 7) Semi-finished product rolling – Third rolling pass: This rolling pass consists of five passes, with a total deformation of 44.65%; the deformation of the first pass is 10.26%-11.46%; the deformation of the second pass is 11.24%-11.87%; the deformation of the third pass is:

[0019] The deformation amount for the fourth pass was 10.76%-11.24%; the deformation amount for the fifth pass was 11.16%-11.64%.

[0020] 10.30%-11.86%;

[0021] 8) Third vacuum heat treatment of semi-finished products: heat treatment temperature 780±20℃, hold for 1 hour and then cool, vacuum degree 10. - 3 MPa;

[0022] 9) Finished Product Rolling – Fourth Pass: This pass consists of four passes, with a total deformation of 34.44%; the deformation of the first pass is 9.87%-11.01%; the deformation of the second pass is 10.70%-11.01%; the deformation of the third pass is:

[0023] 9.33%-9.53%; the deformation amount of the fourth pass is: 8.69%-10.15%;

[0024] 11) Finished product.

[0025] As a preferred technical solution, the rolling speed for the above four rolling passes is 8-10 m / min.

[0026] As a preferred technical solution, the diameter of the pure zirconium wire rod is 6mm; thus, a zirconium wire product with a diameter of 2mm is obtained.

[0027] As a preferred technical solution, the diameter changes from Φ6.00 to Φ4.460 in the first rolling stroke; from Φ4.460 to Φ3.320 in the second rolling stroke; from Φ3.320 to Φ2.470 in the third rolling stroke; and from Φ2.470 to Φ2.000 in the fourth rolling stroke.

[0028] As a preferred technical solution, the finished zirconium wire has a yield strength >460MPa, tensile strength >500MPa, and elongation >5%.

[0029] The advantages and positive effects of this invention are:

[0030] This invention discloses a processing technology for small-diameter zirconium wire, which processes 6mm diameter pure zirconium wire rod into 2mm zirconium wire. By precisely controlling the reduction and deformation rate of each rolling pass based on multiple rolling passes, and supplementing each rolling pass with a reasonable vacuum heat treatment process, small-diameter zirconium wire that meets market requirements can be produced. This invention not only eliminates the need for coating protection of zirconium wire, but also avoids the use of pickling process. In addition, since this invention can complete the rolling process with only 4 rolling passes, the production cycle is greatly shortened. Attached Figure Description

[0031] Figure 1 This is a graph showing the change of mechanical properties in the annealed state with the total processing rate in this invention. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below; obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. 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.

[0033] A processing technology for small-diameter zirconium wire, wherein the raw material for preparing the zirconium wire is pure zirconium wire rod, the chemical composition of which is zirconium element Zr, and the purity can reach over 99.95%; to obtain the finished small-diameter zirconium wire, the following processing technology is required:

[0034] 1) Incoming materials

[0035] Pure zirconium wire rods with a diameter of 6 mm were prepared as raw materials; the raw material diameter was 6 mm; its physical properties were: yield strength 171 MPa; tensile strength 415 MPa; elongation 24.5%;

[0036] 2) Raw material heat treatment

[0037] The raw materials were subjected to vacuum heat treatment: 780±20℃, held for 1 hour, with a vacuum degree of 10. -3 MPa; (Based on the properties and chemical composition of pure zirconium wire rod, analyze the purpose of this heat treatment and the changes in material properties after heat treatment)

[0038] 3) Raw material rolling (first rolling pass)

[0039] The diameter of this rolling process varies from Φ6.00 to Φ4.460, with a total deformation of 44.75%. This rolling process is divided into five passes, and the reduction and deformation of each pass are shown in Table 1-3. The rolling speed is 10 m / min.

[0040] 4) Heat treatment of semi-finished products

[0041] The semi-finished product is subjected to vacuum heat treatment: 780±20℃, held for 1 hour, vacuum degree 10. -3 MPa;

[0042] 5) Semi-finished product rolling (second rolling pass)

[0043] The diameter of this rolling process varies from Φ4.460 to Φ3.320, with a total deformation of 44.59%. This rolling process is divided into five passes, and the reduction and deformation of each pass are shown in Table 1-3. The rolling speed is 9.2 m / min.

[0044] 6) Heat treatment of semi-finished products

[0045] The semi-finished product is subjected to vacuum heat treatment: 780±20℃, held for 1 hour, vacuum degree 10. -3 MPa;

[0046] 7) Semi-finished product rolling (third rolling pass)

[0047] The diameter of this rolling process varies from Φ3.320 to Φ2.470, with a total deformation of 44.65%. This rolling process is divided into five passes, and the reduction and deformation of each pass are shown in Table 1-3. The rolling speed is 8.7 m / min.

[0048] 8) Heat treatment of semi-finished products

[0049] The semi-finished product is subjected to vacuum heat treatment: 780±20℃, held for 1 hour, vacuum degree 10. -3 MPa;

[0050] 9) Finished product rolling (fourth rolling pass)

[0051] The diameter of this rolling pass varies from Φ2.470 to Φ2.000, with a total deformation of 34.44%. This rolling pass is divided into four passes, each...

[0052] The reduction and deformation per pass are shown in Table 1-3; the rolling speed is 8 m / min;

[0053] 10) Finished product

[0054] The surface is free of visible defects; yield strength > 460 MPa; tensile strength > 500 MPa; elongation > 5%.

[0055] The reasons for using vacuum heat treatment in the above heat treatment process are as follows: The main reasons for using vacuum during zirconium wire heat treatment are: 1. To avoid oxidation; zirconium wire is easily oxidized at high temperatures, and oxides will form on the surface of the zirconium wire after oxidation, which seriously affects the surface properties of the zirconium wire. Normally, acid pickling and peeling are required. However, vacuum heat treatment can effectively avoid problems such as oxidation, crystallization, and residues in the zirconium wire, while also improving the purity and quality of the zirconium wire; 2. To reduce grain size; zirconium wire is prone to crystallization at high temperatures, resulting in larger grains. Vacuum treatment can reduce the grain size, improving the toughness, strength, and thermal stability of the zirconium wire; 3. To remove residues; vacuum treatment can completely remove gases and impurities from the zirconium wire, improving its purity and quality; 4. To lower the processing temperature; vacuum treatment can lower the processing temperature, reducing the deformation and stress of the zirconium wire, and avoiding problems such as deformation or breakage during the processing.

[0056] After each vacuum heat treatment, the tensile strength σ of the zirconium wire... b When the total processing rate is low (approximately ≤26%), the elongation gradually increases with the increase of the total processing rate, then gradually decreases, and remains basically stable after 46%; however, it begins to decrease sharply at 80%-84%, reaching its lowest point at approximately 82%; the change trend of yield strength is similar to that of tensile strength; the elongation decreases when the total processing rate is low (approximately ≤26%), then turns to increase, and exhibits a sawtooth-shaped fluctuation after ≥4%, reaching its highest point at 82%, showing a change trend opposite to that of tensile strength and yield strength.

[0057] Zirconium wire is produced using a multi-pass, multi-stage rolling process, with a single-pass deformation of <12% and a total deformation of <45% per pass. Combined with vacuum heat treatment, zirconium wire with a yield strength of 480-670 MPa, a tensile strength of 520-730 MPa, an elongation of 7.5-14.5%, and a diameter of 2 mm can be obtained. This process avoids multiple pickling steps, improves production efficiency, and prevents environmental pollution.

[0058] Example 1

[0059] The specific process parameters for this embodiment are shown in Table 1:

[0060] Table 1:

[0061]

[0062]

[0063] Finished product properties: Yield strength 504 MPa; Tensile strength 627 MPa; Elongation 14.5%.

[0064] Example 2

[0065] The specific process parameters for this embodiment are shown in Table 2:

[0066] Table 2:

[0067]

[0068] Finished product properties: Yield strength 668MPa; Tensile strength 721MPa; Elongation 10.5%.

[0069] Example 3:

[0070] The specific process parameters for this embodiment are shown in Table 3:

[0071] Table 3:

[0072]

[0073] Finished product properties: Yield strength 482MPa; Tensile strength 522MPa; Elongation 7.5%.

[0074] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made in accordance with the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A processing technology for small-diameter zirconium wire, characterized in that: The process includes the following steps: 1) Material preparation: Prepare pure zirconium wire rods as raw materials; 2) The raw materials are subjected to vacuum heat treatment at a temperature of 780±20℃, held for 1 hour, and then cooled. The vacuum degree is 10. -3 MPa; 3) Raw material rolling – First pass: This pass consists of five passes, with a total deformation of 44.75%; the deformation of the first pass is 10.76%-11.51%; the deformation of the second pass is 11.55%-11.67%; the deformation of the third pass is 11.51%-11.69%; the deformation of the fourth pass is 10.76%-11.66%; and the deformation of the fifth pass is 9.57%-10.64%. 4) First vacuum heat treatment of semi-finished products: heat treatment temperature 780±20℃, hold for 1 hour and then cool, vacuum degree 10. -3 MPa; 5) Semi-finished product rolling – Second rolling pass: This rolling pass consists of five passes, with a total deformation of 44.59%; the deformation of the first pass is 10.81%-11.74%; the deformation of the second pass is 11.17%-11.70%; the deformation of the third pass is: The deformation in the fourth pass was 11.26%-11.39%; the deformation in the fifth pass was 11.16%-11.42%; and the deformation in the fifth pass was 9.82%-10.64%. 6) Second vacuum heat treatment of semi-finished products: heat treatment temperature 780±20℃, hold for 1 hour and then cool, vacuum degree 10. -3 MPa; 7) Semi-finished product rolling – Third rolling pass: This rolling pass consists of five passes, with a total deformation of 44.65%; the deformation of the first pass is 10.26%-11.46%; the deformation of the second pass is 11.24%-11.87%; the deformation of the third pass is: The deformation in the fourth pass was 10.76%-11.24%; the deformation in the fifth pass was 11.16%-11.64%; and the deformation in the fifth pass was 10.30%-11.86%. 8) Third vacuum heat treatment of semi-finished products: heat treatment temperature 780±20℃, hold for 1 hour and then cool, vacuum degree 10. -3 MPa; 9) Finished Product Rolling – Fourth Pass: This pass consists of four passes, with a total deformation of 34.44%; the deformation of the first pass is 9.87%-11.01%; the deformation of the second pass is 10.70%-11.01%; the deformation of the third pass is: 9.33%-9.53%; the deformation amount of the fourth pass is: 8.69%-10.15%; 10) Finished product.

2. The processing technology for small-diameter zirconium wire as described in claim 1, characterized in that: The rolling speed for the above four rolling passes is 8-10 m / min.

3. The processing technology for small-diameter zirconium wire as described in claim 1, characterized in that: The pure zirconium wire rod has a diameter of 6 mm, resulting in a finished zirconium wire with a diameter of 2 mm.

4. The processing technology for small-diameter zirconium wire as described in claim 3, characterized in that: The diameter changes from Φ6.00 to Φ4.460 in the first rolling pass; from Φ4.460 to Φ3.320 in the second rolling pass; from Φ3.320 to Φ2.470 in the third rolling pass; and from Φ2.470 to Φ2.000 in the fourth rolling pass.

5. The processing technology for small-diameter zirconium wire as described in claim 1, characterized in that: The finished zirconium wire has a yield strength >460MPa, tensile strength >500MPa, and elongation >5%.

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