Method for instantly enhancing strength of austenitic stainless steel wire

Abstract

The invention belongs to the technical field of austenitic stainless steel wires, and provides a method for instantaneously enhancing the strength of an austenitic stainless steel wire. The method comprises the following steps: connecting a pulse power supply to the stainless steel wire, carrying out electric pulse treatment, and naturally cooling to obtain the reinforced austenitic stainless steel wire. The austenitic stainless steel wire is treated through the electric pulse, the strength of the austenitic stainless steel wire can be remarkably improved within a short time, the organization structure, corrosion resistance and abrasion resistance of the austenitic stainless steel wire cannot be changed, consumed time is short, and efficiency is high.

Description

Technical Field

[0001] The invention relates to the technical field of austenitic stainless steel wires, and in particular to a method for instantaneously enhancing the strength of austenitic stainless steel wires. Background Art

[0002] Austenitic stainless steel wire is widely used in modern industries such as petrochemical, automobile manufacturing, construction, national defense, military, aerospace, and civil industries due to its excellent corrosion resistance, wear resistance, surface stability, strength, and ductility. With the development of industry production technology, modern industries such as national defense, military, and aerospace have higher and higher requirements for the strength of stainless steel wire braided tubes, which has prompted the production of stainless steel wire to expand in the direction of ultra-high strength, ductility, and corrosion resistance. Therefore, improving the strength of austenitic stainless steel wire is of great significance to promoting the further development of my country's stainless steel wire products industry.

[0003] The matrix structure of austenitic stainless steel wire is a single austenite. No phase change occurs during the cooling of the austenite to room temperature, so the austenitic stainless steel wire cannot be strengthened by phase change, that is, the strength of the austenitic stainless steel wire cannot be improved by ordinary heat treatment. At present, the strength of austenitic stainless steel wire is mostly improved by cold drawing processes with multiple large deformations. Under the action of tension, the original wire rod passes through the wire drawing die hole to obtain the required size and strength. Compared with other plastic deformation processing methods, the cold drawing process has the characteristics of low equipment cost, easy operation, high dimensional accuracy, wide production conditions, and flexible variety and specification changes. However, due to the limitations of the processing method and the austenitic stainless steel material itself, it is difficult to continue to improve the strength of austenitic stainless steel wire after severe plastic deformation, which limits the application of austenitic stainless steel wire to a certain extent.

[0004] Therefore, developing a method that can further improve the strength of austenitic stainless steel wire has broad application prospects. Summary of the invention

[0005] The purpose of the present invention is to provide a method for instantaneously enhancing the strength of austenitic stainless steel wire in view of the deficiencies in the prior art.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for instantaneously enhancing the strength of austenitic stainless steel wire, wherein a pulse power source is connected to the cold-drawn stainless steel wire, an electric pulse treatment is performed, and the enhanced austenitic stainless steel wire is obtained by natural cooling;

[0008] The electric pulse output form of the electric pulse processing is a unidirectional pulse square wave.

[0009] Preferably, the cold-drawn stainless steel wire comprises cold-drawn 304 stainless steel wire or cold-drawn 316L stainless steel wire.

[0010] Preferably, the diameter of the cold-drawn stainless steel wire is 0.1-0.5 mm.

[0011] Preferably, the current density of the electric pulse treatment is 850-1500 A / cm 2 .

[0012] Preferably, the frequency of the electric pulse treatment is 400-600 Hz.

[0013] Preferably, the duty cycle of the electric pulse treatment is 20-40%.

[0014] Preferably, the temperature of the electric pulse treatment is 25-400° C., and the time of the electric pulse treatment is 5-30 seconds.

[0015] The beneficial effects of the present invention include the following:

[0016] 1) The present invention uses electric pulse treatment on cold-drawn austenitic stainless steel wire, which can significantly improve the strength of the austenitic stainless steel wire in a short time without changing the organizational structure, corrosion resistance and wear resistance of the austenitic stainless steel wire, with short time and high efficiency.

[0017] 2) The thermal and non-thermal effects of electric pulse treatment promote the annihilation of dislocations within the grain of cold-drawn austenitic stainless steel wire, resulting in a reduction in movable dislocations within the grain, and the corresponding grain boundaries become dislocation sources; when plastic deformation occurs, movable dislocations that slip can only occur at grain boundaries, and the force required to activate the dislocation source on the grain boundary is much greater than that required to activate the dislocation source within the grain, that is, the yield strength of the cold-drawn austenitic stainless steel wire is increased under the action of electric pulses.

[0018] 3) With the increase of drawing passes, the grain size inside the cold-drawn austenitic stainless steel wire continues to decrease, and its own work hardening ability continues to weaken, thus restricting the improvement of tensile strength. However, under electric pulse treatment, the movable dislocations in the cold-drawn austenitic stainless steel wire are reduced, and its grain boundaries relax, which in turn improves the work hardening ability of the cold-drawn austenitic stainless steel wire, thereby improving the tensile strength of the cold-drawn austenitic stainless steel wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The stress-strain curves of cold-drawn 304 stainless steel wire after 30s electric pulse treatment and without electric pulse treatment;

[0020] Figure 2 This is the relationship curve between the treatment time and hardness of cold drawn 304 stainless steel wire in electric pulse treatment;

[0021] Figure 3 This is a diagram of the device for electric pulse processing of cold-drawn stainless steel wire according to the present invention. DETAILED DESCRIPTION

[0022] The present invention provides a method for instantaneously enhancing the strength of austenitic stainless steel wire, wherein a pulse power source is connected to the cold-drawn stainless steel wire, an electric pulse treatment is performed, and the enhanced austenitic stainless steel wire is obtained by natural cooling;

[0023] The electric pulse output form of the electric pulse processing is a unidirectional pulse square wave.

[0024] In the present invention, the cold-drawn stainless steel wire preferably includes cold-drawn 304 stainless steel wire or cold-drawn 316L stainless steel wire.

[0025] In the present invention, the diameter of the cold-drawn stainless steel wire is preferably 0.1 to 0.5 mm, more preferably 0.2 to 0.4 mm, and even more preferably 0.3 mm.

[0026] In the present invention, the current density of the electric pulse treatment is preferably 850 to 1500 A / cm 2 , more preferably 900 to 1400 A / cm 2 , more preferably 1000 to 1200 A / cm 2 .

[0027] In the present invention, the frequency of the electric pulse treatment is preferably 400 to 600 Hz, more preferably 450 to 550 Hz, and even more preferably 500 Hz.

[0028] In the present invention, the duty ratio of the electric pulse treatment is preferably 20 to 40%, more preferably 25 to 35%, and even more preferably 30%.

[0029] In the present invention, the temperature of the electric pulse treatment is preferably 25-400°C, more preferably 100-250°C, and more preferably 200°C; the time of the electric pulse treatment is preferably 5-30s, more preferably 10-25s, and more preferably 15-20s.

[0030] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0031] Example 1

[0032] Cut a 50cm long, 0.3mm diameter cold drawn 304 stainless steel wire and Figure 3 The pulse power supply is connected to the stainless steel wire, using a unidirectional pulse square wave at a frequency of 500 Hz and 1400 A / cm 2The electric pulse treatment was carried out for 30 seconds with a current density of 1000 nm and a duty cycle of 30%. The temperature of the electric pulse treatment was 200° C., and the sample was cooled naturally after the treatment.

[0033] According to the room temperature tensile test method for metal materials in GB / T 228-2002, tensile tests were performed on cold-drawn 304 stainless steel wires treated with 30s electric pulses and those without electric pulses, and the stress-strain curves of cold-drawn 304 stainless steel wires treated with 30s electric pulses and those without electric pulses were obtained. Figure 1 shown.

[0034] Depend on Figure 1 It can be seen that the tensile strength of the cold-drawn 304 stainless steel wire treated with 30s electric pulse is 350MPa (19%) higher than that of the wire without electric pulse treatment. From the tensile test results, it can be seen that the yield strength of the cold-drawn 304 stainless steel wire treated with 30s electric pulse (2029MPa) is 240MPa (13%) higher than that of the wire without electric pulse treatment (1789MPa).

[0035] According to the Vickers hardness test of metal materials in GB / T 43402009, the hardness of cold-drawn 304 stainless steel wire treated with electric pulse for 5s, 10s, 20s and 30s was tested, and the relationship curve between different electric pulse treatment time and the hardness of cold-drawn 304 stainless steel wire was obtained, as shown in Figure 2. Figure 2 shown.

[0036] Depend on Figure 2 It can be seen that the hardness of the cold-drawn 304 stainless steel wire increases with the increase of the electric pulse treatment time, reaching 640HV after 30s of electric pulse treatment, which is 20% higher than that without electric pulse treatment (535HV).

[0037] Example 2

[0038] Cut a 50cm long, 0.1mm diameter Nippon Steel cold drawn 304 stainless steel wire and Figure 3 The pulse power supply is connected to the stainless steel wire, using a unidirectional pulse square wave at a frequency of 500 Hz and 1400 A / cm 2 The electric pulse treatment was carried out for 30 seconds with a current density of 1000 nm and a duty cycle of 30%. The temperature of the electric pulse treatment was 200° C., and the sample was cooled naturally after the treatment.

[0039] According to GB / T 228-2002 room temperature tensile test method for metal materials, the tensile strength of Nippon Steel's cold-drawn 304 stainless steel wire was tested before and after electric pulse treatment. The tensile strength of Nippon Steel's cold-drawn 304 stainless steel wire after electric pulse treatment was 2100 MPa, which was 17% higher than that before electric pulse treatment (1800 MPa).

[0040] Example 3

[0041] Cut a 50cm long, 0.3mm diameter cold drawn 316L stainless steel wire and Figure 3 The pulse power supply is connected to the stainless steel wire, using a unidirectional pulse square wave at a frequency of 500 Hz and 1400 A / cm 2 The electric pulse treatment was carried out for 30 seconds with a current density of 1000 nm and a duty cycle of 30%. The temperature of the electric pulse treatment was 200° C., and the sample was cooled naturally after the treatment.

[0042] According to GB / T 228-2002 room temperature tensile test method for metal materials, the tensile strength of cold-drawn 316L stainless steel wire was tested before and after electric pulse treatment. The tensile strength of cold-drawn 316L stainless steel wire after electric pulse treatment was 2290 MPa, which was 14.5% higher than that before electric pulse treatment (2000 MPa).

[0043] Example 4

[0044] Cut a 50cm long, 0.5mm diameter cold drawn 304 stainless steel wire and Figure 3 The pulse power supply is connected to the stainless steel wire, using a unidirectional pulse square wave at a frequency of 550 Hz and 1400 A / cm 2 The electric pulse treatment was carried out for 25 seconds with a current density of 1000 ℃ and a duty cycle of 25%. The temperature of the electric pulse treatment was 200℃, and the electrode was cooled naturally after the treatment.

[0045] According to GB / T 228-2002 room temperature tensile test method for metal materials, the tensile strength of cold-drawn 304 stainless steel wire before and after electric pulse treatment was tested. The tensile strength of cold-drawn 304 stainless steel wire after electric pulse treatment was 2246 MPa, which was 17.8% higher than that before electric pulse treatment (1906 MPa).

[0046] Example 5

[0047] Cut a 50cm long, 0.4mm diameter cold drawn 304 stainless steel wire and Figure 3 The pulse power supply is connected to the stainless steel wire, using a unidirectional pulse square wave at a frequency of 450Hz and 1500A / cm 2 The electric pulse treatment was carried out for 15 seconds with a current density of 1000 and a duty cycle of 35%. The temperature of the electric pulse treatment was 250°C, and the electrode was naturally cooled after the treatment.

[0048] The tensile strength of the cold-drawn 304 stainless steel wire before and after the electric pulse treatment was tested according to the room temperature tensile test method for metal materials in GB / T 228-2002. The tensile strength of the cold-drawn 304 stainless steel wire after the electric pulse treatment was 2230 MPa, which was 18% higher than that before the electric pulse treatment (1890 MPa).

[0049] Comparative Example 1

[0050] The electric pulse treatment time in Example 1 was changed to 1 s, and other conditions were the same as in Example 1.

[0051] According to GB / T 228-2002 room temperature tensile test method for metal materials, the tensile strength of cold-drawn 304 stainless steel wire before and after electric pulse treatment was tested. The tensile strength of cold-drawn 304 stainless steel wire after electric pulse treatment was 1943 MPa, which was only 2.6% higher than that before electric pulse treatment (1893 MPa).

[0052] Comparative Example 2

[0053] The current density in Example 1 was changed to 800 A / cm 2 , other conditions are the same as in Example 1.

[0054] According to GB / T 228-2002 room temperature tensile test method for metal materials, the tensile strength of cold-drawn 304 stainless steel wire before and after electric pulse treatment was tested. The tensile strength of cold-drawn 316L stainless steel wire after electric pulse treatment was 1993 MPa, which was only 5.2% higher than that before electric pulse treatment (1893 MPa).

[0055] Comparative Example 3

[0056] The current density in Example 1 was changed to 1600 A / cm 2 , other conditions are the same as in Example 1.

[0057] According to GB / T 228-2002 room temperature tensile test method for metal materials, the tensile strength of cold-drawn 304 stainless steel wire before and after electric pulse treatment was tested. The tensile strength of cold-drawn 304 stainless steel wire after electric pulse treatment was 2053 MPa, which was only 8.4% higher than that before electric pulse treatment (1893 MPa).

[0058] Comparative Example 4

[0059] The duty cycle in Example 1 is changed to 10%, and other conditions are the same as in Example 1.

[0060] According to GB / T 228-2002 room temperature tensile test method for metal materials, the tensile strength of cold-drawn 304 stainless steel wire before and after electric pulse treatment was tested. The tensile strength of cold-drawn 304 stainless steel wire after electric pulse treatment was 1943 MPa, which was only 2.6% higher than that before electric pulse treatment (1893 MPa).

[0061] Comparative Example 5

[0062] The duty cycle in Example 1 is changed to 50%, and other conditions are the same as in Example 1.

[0063] According to GB / T 228-2002 room temperature tensile test method for metal materials, the tensile strength of cold-drawn 304 stainless steel wire before and after electric pulse treatment was tested. The tensile strength of cold-drawn 304 stainless steel wire after electric pulse treatment was 2043 MPa, which was only 7.9% higher than that before electric pulse treatment (1893 MPa).

[0064] It can be seen from the test results of Example 1 and Comparative Examples 1 to 5 that the present invention adopts electric pulse treatment, and by reasonably controlling the temperature, frequency, current density, duty cycle, time and other process parameters of the electric pulse, multiple process parameters can be coordinated with each other to achieve instantaneous enhancement of the strength of the austenitic stainless steel wire. The method of instantaneous enhancement of the strength of austenitic stainless steel wire of the present invention is particularly suitable for austenitic stainless steel wire enhanced by cold drawing process, so that the tensile strength of the cold drawn stainless steel wire is further increased by 19%, the yield strength is further increased by 12%, and the hardness is further increased by 20%.

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for instantaneously enhancing the strength of austenitic stainless steel wire, characterized in that: Connect a pulse power supply to the cold-drawn stainless steel wire, perform electric pulse treatment, and cool naturally to obtain the reinforced austenitic stainless steel wire; The electric pulse output form of the electric pulse processing is a unidirectional pulse square wave.

2. The method according to claim 1, characterized in that The cold-drawn stainless steel wire includes cold-drawn 304 stainless steel wire or cold-drawn 316L stainless steel wire.

3. The method according to claim 1 or 2, characterized in that: The diameter of the cold-drawn stainless steel wire is 0.1-0.5 mm.

4. The method according to claim 3, characterized in that The current density of the electric pulse treatment is 850-1500A / cm 2 .

5. The method according to claim 4, characterized in that The frequency of the electric pulse treatment is 400-600 Hz.

6. The method according to claim 4 or 5, characterized in that: The duty cycle of the electric pulse treatment is 20-40%.

7. The method according to claim 6, characterized in that The temperature of the electric pulse treatment is 25-400° C., and the time of the electric pulse treatment is 5-30 seconds.

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