Forming method of U-shaped steel wire for snap spring

Abstract

The invention discloses a forming method of a U-shaped steel wire for a clamp spring, and belongs to the technical field of metal processing. The processing method is realized through the following steps: A, rolling the flat steel wire; b, first induction heating; c, first-time high-pressure washing; d, drying for the first time; e, semi-finished product pass rolling; f, secondary induction heating; g, secondary high-pressure washing; h, secondary drying; and I, finished product pass rolling. The adverse effects caused by work hardening and non-uniform deformation of the U-shaped steel wire in the machining process can be effectively eliminated through two times of induction heating; a blank steel wire with a clean and dry surface is provided for subsequent rolling through two times of high-pressure washing and two times of drying; the large-deformation-amount deformation of the U-shaped steel wire for the clamp spring is smoothly completed through two times of slotted hole forming, and the obtained U-shaped steel wire is not prone to cracking, so that rapid and stable forming of the U-shaped steel wire is achieved, and the forming quality and the production efficiency of the U-shaped steel wire are greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of metal processing, and specifically relates to a forming method of a U-shaped steel wire for a retaining spring, and is particularly suitable for processing the U-shaped steel wire represented by 72B. Background Art

[0002] 72B steel is a carbon spring steel with a manganese content between 0.6% and 0.9%. The higher manganese content enhances its mechanical properties, strength, toughness and elasticity. It has high strength and hardness, high elastic limit and fatigue limit, especially notch fatigue limit, but poor welding performance and cold plastic deformation ability. It has better cutting performance after annealing. At present, 72B steel is widely used in the manufacture of various springs, and can also be used to manufacture other elastic components and wear-resistant parts.

[0003] At present, the forming methods of U-shaped steel wire are generally cold rolling or die drawing. The defects of the cold rolling method are: due to the high carbon content and severe work hardening of 72B steel, the U-shaped steel wire can only be formed with a small deformation during cold rolling, and the forming roller is easy to collapse; at the same time, due to the uneven deformation of the U-shaped steel wire, it is very easy to cause the side cracking of the U-shaped steel wire, and the production efficiency is very low. The shortcomings of the die drawing method are: there are many die passes (generally more than 10 passes are required), the steel wire is severely deformed, especially the deformation of the U-shaped groove position is particularly prominent, and the mold is easily damaged, which leads to extremely high production costs and low efficiency. In summary, due to the special shape of the U-shaped steel wire, severe and uneven deformation, the production efficiency is very low whether it is formed by cold rolling or die drawing, and it is impossible to achieve efficient and stable production. Summary of the invention

[0004] The purpose of the present invention is to provide a forming method for a U-shaped steel wire for a circlip in view of the shortcomings of the above-mentioned prior art. The forming method of the present invention can effectively eliminate the adverse effects caused by the work hardening and uneven deformation of the U-shaped steel wire during the processing, smoothly complete the large deformation of the U-shaped steel wire for the circlip, and the obtained U-shaped steel wire is not easy to crack, thereby realizing the rapid and stable forming of the U-shaped steel wire, greatly improving the forming quality and production efficiency of the U-shaped steel wire.

[0005] The purpose of the present invention can be achieved by the following technical measures: The forming method of a U-shaped steel wire for a clip spring of the present invention is achieved by the following steps: A. Flat steel wire rolling: After the round steel wire is unrolled by the pay-off device, it is first rolled by a two-roll rolling mill to obtain a flat steel wire; the cross-sectional width of the flat steel wire is equal to the cross-sectional width of the finished steel wire; B. First induction heating: the flat steel wire obtained in step A continues to move forward and passes through the inner cavity of the induction heating device I for first induction heating. The first induction heating temperature is 500-600°C to soften the steel wire and increase its plastic toughness. C. First high-pressure flushing: After the first induction heating, the flat steel wire will form oxide scale on the surface. The flat steel wire continues to move forward and passes through the inner cavity of the high-pressure water tank I to perform the first high-pressure flushing on the surface of the flat steel wire. After removing the surface oxide scale, a clean flat steel wire is obtained; D. First drying: The flat steel wire with a clean surface obtained after the first high-pressure washing continues to move forward and passes through the inner cavity of the drying device I to be dried for the first time, evaporating the water remaining on the surface of the flat steel wire to obtain a flat steel wire with a dry surface; E. Semi-finished product pass rolling: The flat steel wire with dry surface continues to move forward and passes through the semi-finished product pass rolling mill to obtain the semi-finished steel wire; the U-shaped groove depth of the semi-finished steel wire is 60% of the U-shaped groove depth of the finished steel wire; F. Secondary induction heating: The semi-finished steel wire obtained in step E continues to move forward and passes through the inner cavity of the induction heating device II for secondary induction heating. The secondary induction heating temperature is 500-600°C to soften the steel wire and increase the plastic toughness of the steel wire. G. Secondary high-pressure washing: After the secondary induction heating, the semi-finished steel wire will form oxide scale on the surface. The semi-finished steel wire continues to move forward and passes through the inner cavity of the high-pressure water tank II to perform secondary high-pressure washing on the surface of the semi-finished steel wire. After removing the surface oxide scale, the semi-finished steel wire with a clean surface is obtained. H. Secondary drying: The semi-finished steel wire with a clean surface obtained after the secondary high-pressure washing continues to move forward and passes through the inner cavity of the drying device II to perform secondary drying on the semi-finished steel wire, evaporating the water remaining on the surface of the semi-finished steel wire to obtain a semi-finished steel wire with a dry surface; I. Finished product pass rolling: The semi-finished steel wire with dry surface continues to move forward and passes through the finished product pass rolling mill for finished product pass rolling to obtain the finished steel wire and complete the U-shaped steel wire forming; J. Reeling and warehousing: As the take-up machine rotates, the finished steel wire is wound onto the I-shaped wheel of the take-up machine for reeling, and then packaged and stored.

[0006] The design principle of the present invention is as follows: The forming method of the present invention is to firstly roll the round steel wire through a two-roll rolling mill to obtain a flat steel wire with a width dimension equal to that of the finished steel wire. Such a flat steel wire can ensure that in the subsequent forming process, it only needs to be deformed in the thickness direction of the steel wire, which simplifies the hole design and reduces the processing difficulty; then, the flat steel wire is subjected to the first induction heating to eliminate the work hardening of the steel wire, improve the plastic toughness of the flat steel wire, provide a guarantee for uniform deformation in the subsequent rolling process, and lay a foundation for the stable rolling and stable forming of the semi-finished hole; then, the flat steel wire is subjected to the first high-pressure washing and the first Drying, the first high-pressure washing can effectively remove the oxide scale formed on the surface of the flat steel wire after the first induction heating, and the first drying can evaporate the moisture remaining on the surface of the flat steel wire, so that a flat steel wire with a clean and dry surface can be obtained. The flat steel wire with a clean and dry surface enters the semi-finished hole-shaped rolling mill for rolling to obtain a semi-finished steel wire with a U-shaped groove depth of 60% of the U-shaped groove depth of the finished steel wire; followed by secondary induction heating, secondary high-pressure washing, and secondary drying of the semi-finished steel wire, and then enters the finished hole-shaped rolling mill for rolling to obtain a finished U-shaped steel wire. In this way, the present invention can effectively eliminate the adverse effects of work hardening and uneven deformation of the U-shaped steel wire during the processing process through two induction heatings before and after; through two high-pressure washings and two dryings before and after, a clean and dry embryo steel wire is provided for subsequent rolling; through two slot hole formings before and after, the large deformation of the U-shaped steel wire for the retaining spring is successfully completed, and the obtained U-shaped steel wire is not easy to crack, thereby realizing the rapid and stable forming of the U-shaped steel wire, greatly improving the forming quality and production efficiency of the U-shaped steel wire.

[0007] The beneficial technical effects of the present invention are as follows: The forming method of the present invention can effectively eliminate the adverse effects of work hardening and uneven deformation of the U-shaped steel wire during the processing, successfully complete the large deformation of the U-shaped steel wire for the retaining spring, and the obtained U-shaped steel wire is not easy to crack, thereby realizing rapid and stable forming of the U-shaped steel wire, greatly improving the forming quality and production efficiency of the U-shaped steel wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic diagram of the process arrangement and process flow of the present invention.

[0009] Figure 2 It is a cross-sectional schematic diagram of a U-shaped steel wire.

[0010] Explanation of the part numbers in the figure: 1. Pay-off device, 2. Round steel wire, 3. Two-roller rolling mill, 4. Flat steel wire, 5. Induction heating device I, 6. High-pressure water tank I, 7. Drying device I, 8. Semi-finished steel wire hole-type rolling mill, 9. Semi-finished steel wire, 10. Induction heating device II, 11. High-pressure water tank II, 12. Drying device II, 13. Finished steel wire hole-type rolling mill, 14. Finished steel wire, 15. Wire take-up machine, W, finished steel wire cross-sectional width, H, finished steel wire cross-sectional height, b, finished steel wire U-shaped groove width, h, finished steel wire U-shaped groove depth. DETAILED DESCRIPTION

[0011] The present invention is further described below in conjunction with the accompanying drawings and embodiments (refer to Figure 1 , Figure 2 ): Embodiment 1

[0012] like Figure 1 , Figure 2 As shown, a forming method of a U-shaped steel wire for a clip spring in the first embodiment is achieved by the following steps: A. Flat steel wire rolling: a round steel wire 2 with a material of 72B and a diameter of Φ4.25 is unfolded by a pay-off device 1 and then subjected to an initial two-roll rolling by a two-roll rolling mill 3 to obtain a flat steel wire 4 with a cross-sectional size of 6.2mm*1.76mm; the cross-sectional width of the flat steel wire 4 is equal to the cross-sectional width W of the finished steel wire, i.e., both are 6.2mm; B. First induction heating: The flat steel wire 4 with a cross-sectional size of 6.2 mm*1.76 mm obtained in step A continues to move forward and passes through the inner cavity of the induction heating device I5 for first induction heating. The first induction heating temperature is 500°C to achieve the purpose of softening the steel wire and increasing the plastic toughness of the steel wire; C. First high-pressure flushing: After the first induction heating, the flat steel wire 4 will form oxide scale on the surface. The flat steel wire 4 continues to move forward and passes through the inner cavity of the high-pressure water tank Ⅰ6 to perform the first high-pressure flushing on the surface of the flat steel wire, and the surface oxide scale is removed to obtain a clean flat steel wire 4; D. First drying: The flat steel wire 4 with a clean surface obtained after the first high-pressure washing continues to move forward and passes through the inner cavity of the drying device Ⅰ 7 to perform the first drying on the flat steel wire 4, evaporating the water remaining on the surface of the flat steel wire to obtain the flat steel wire 4 with a dry surface; E. Semi-finished product pass rolling: The flat steel wire 4 with a dry surface and a cross-sectional size of 6.2 mm*1.76 mm continues to move forward and passes through a semi-finished product pass rolling mill 8 for semi-finished product pass rolling to obtain a semi-finished product steel wire 9 with a cross-sectional size of 6.2 mm*1.58 mm and a U-shaped groove section of 5 mm*0.54 mm; the U-shaped groove depth of the semi-finished product steel wire 9 is 60% of the U-shaped groove depth h of the finished steel wire (i.e., the U-shaped groove depth h of the finished steel wire is 0.9 mm); F. Secondary induction heating: The semi-finished steel wire 9 obtained in step E with a cross-sectional size of 6.2 mm*1.58 mm and a U-shaped groove cross-sectional size of 5 mm*0.54 mm continues to move forward and passes through the inner cavity of the induction heating device II 10 for secondary induction heating. The secondary induction heating temperature is 500° C., so as to soften the steel wire and increase the plastic toughness of the steel wire. G. Secondary high-pressure washing: After the secondary induction heating, the semi-finished steel wire 9 will form oxide scale on the surface. The semi-finished steel wire 9 continues to move forward and passes through the inner cavity of the high-pressure water tank II 11 to perform secondary high-pressure washing on the surface of the semi-finished steel wire, and the surface oxide scale is removed to obtain a clean semi-finished steel wire 9; H. Secondary drying: The semi-finished steel wire 9 with a clean surface obtained after the secondary high-pressure washing continues to move forward, passes through the inner cavity of the drying device II 12 to perform secondary drying on the semi-finished steel wire 9, evaporates the water remaining on the surface of the semi-finished steel wire, and obtains the semi-finished steel wire 9 with a dry surface; I. Finished product pass rolling: The semi-finished steel wire 9 with a dry surface and a cross-sectional size of 6.2 mm*1.58 mm and a U-shaped groove cross-sectional size of 5 mm*0.54 mm continues to move forward and passes through the finished product pass rolling mill 13 for finished product pass rolling to obtain a finished steel wire 14 with a cross-sectional size of 6.2 mm*1.5 mm and a U-shaped groove cross-sectional size of 5 mm*0.9 mm, thereby completing the forming of the U-shaped steel wire; J. Reeling and warehousing: As the wire take-up machine 15 rotates, the finished steel wire 14 with a cross-sectional size of 6.2 mm*1.5 mm and a U-shaped groove cross-sectional size of 5 mm*0.9 mm is wound onto the I-shaped wheel of the wire take-up machine 15 for reeling, and then packaged and warehousing can be performed. Embodiment 2

[0013] like Figure 1 , Figure 2 As shown, a forming method of a U-shaped steel wire for a clip spring in the second embodiment is achieved by the following steps: A. Flat steel wire rolling: a round steel wire 2 with a material of 72B and a diameter of Φ5.05 is unfolded by a pay-off device 1 and then subjected to an initial two-roll rolling by a two-roll rolling mill 3 to obtain a flat steel wire 4 with a cross-sectional size of 7.6mm*2.1mm; the cross-sectional width of the flat steel wire 4 is equal to the cross-sectional width W of the finished steel wire, i.e., both are 7.6mm; B. First induction heating: The flat steel wire 4 with a cross-sectional size of 7.6 mm*2.1 mm obtained in step A continues to move forward and passes through the inner cavity of the induction heating device I5 for first induction heating. The first induction heating temperature is 550° C., so as to soften the steel wire and increase its plastic toughness. C. First high-pressure flushing: After the first induction heating, the flat steel wire 4 will form oxide scale on the surface. The flat steel wire 4 continues to move forward and passes through the inner cavity of the high-pressure water tank Ⅰ6 to perform the first high-pressure flushing on the surface of the flat steel wire, and the surface oxide scale is removed to obtain a clean flat steel wire 4; D. First drying: The flat steel wire 4 with a clean surface obtained after the first high-pressure washing continues to move forward and passes through the inner cavity of the drying device Ⅰ 7 to perform the first drying on the flat steel wire 4, evaporating the water remaining on the surface of the flat steel wire to obtain the flat steel wire 4 with a dry surface; E. Semi-finished product pass rolling: The flat steel wire 4 with a dry surface and a cross-sectional size of 7.6 mm*2.1 mm continues to move forward and passes through the semi-finished product pass rolling mill 8 for semi-finished product pass rolling to obtain a semi-finished product steel wire 9 with a cross-sectional size of 7.6 mm*1.9 mm and a U-shaped groove section of 6 mm*0.6 mm; the U-shaped groove depth of the semi-finished product steel wire 9 is 60% of the U-shaped groove depth h of the finished steel wire (i.e., the U-shaped groove depth h of the finished steel wire is 1 mm); F. Secondary induction heating: The semi-finished steel wire 9 obtained in step E with a cross-sectional size of 7.6 mm*1.9 mm and a U-shaped groove cross-sectional size of 6 mm*0.6 mm continues to move forward and passes through the inner cavity of the induction heating device II 10 for secondary induction heating. The secondary induction heating temperature is 550°C, so as to soften the steel wire and increase the plastic toughness of the steel wire; G. Secondary high-pressure washing: After the secondary induction heating, the semi-finished steel wire 9 will form oxide scale on the surface. The semi-finished steel wire 9 continues to move forward and passes through the inner cavity of the high-pressure water tank II 11 to perform secondary high-pressure washing on the surface of the semi-finished steel wire, and the surface oxide scale is removed to obtain a clean semi-finished steel wire 9; H. Secondary drying: The semi-finished steel wire 9 with a clean surface obtained after the secondary high-pressure washing continues to move forward, passes through the inner cavity of the drying device II 12 to perform secondary drying on the semi-finished steel wire 9, evaporates the water remaining on the surface of the semi-finished steel wire, and obtains the semi-finished steel wire 9 with a dry surface; I. Finished product pass rolling: The semi-finished steel wire 9 with a dry surface and a cross-sectional size of 7.6 mm*1.9 mm and a U-shaped groove cross-sectional size of 6 mm*0.6 mm continues to move forward and passes through the finished product pass rolling mill 13 for finished product pass rolling to obtain a finished steel wire 14 with a cross-sectional size of 7.6 mm*1.8 mm and a U-shaped groove cross-sectional size of 6 mm*1 mm, thereby completing the forming of the U-shaped steel wire; J. Reeling and warehousing: As the wire take-up machine 15 rotates, the finished steel wire 14 with a cross-sectional size of 7.6 mm*1.8 mm and a U-shaped groove cross-sectional size of 6 mm*1 mm is wound onto the I-shaped wheel of the wire take-up machine 15 for reeling, and then packaged and warehousing can be performed. Embodiment 3

[0014] like Figure 1 , Figure 2As shown, a method for forming a U-shaped steel wire for a clip spring in the third embodiment is achieved by the following steps: A. Flat steel wire rolling: a round steel wire 2 with a material of 72B and a diameter of Φ5.9 is unfolded by a pay-off device 1 and then subjected to an initial two-roll rolling by a two-roll rolling mill 3 to obtain a flat steel wire 4 with a cross-sectional size of 8.0 mm*2.35 mm; the cross-sectional width of the flat steel wire 4 is equal to the cross-sectional width W of the finished steel wire, i.e., both are 8.0 mm; B. First induction heating: The flat steel wire 4 with a cross-sectional size of 8.0 mm*2.35 mm obtained in step A continues to move forward and passes through the inner cavity of the induction heating device I5 for first induction heating. The first induction heating temperature is 600° C., so as to soften the steel wire and increase its plastic toughness. C. First high-pressure flushing: After the first induction heating, the flat steel wire 4 will form oxide scale on the surface. The flat steel wire 4 continues to move forward and passes through the inner cavity of the high-pressure water tank Ⅰ6 to perform the first high-pressure flushing on the surface of the flat steel wire, and the surface oxide scale is removed to obtain a clean flat steel wire 4; D. First drying: The flat steel wire 4 with a clean surface obtained after the first high-pressure washing continues to move forward and passes through the inner cavity of the drying device Ⅰ 7 to perform the first drying on the flat steel wire 4, evaporating the water remaining on the surface of the flat steel wire to obtain the flat steel wire 4 with a dry surface; E. Semi-finished product pass rolling: The flat steel wire 4 with a dry surface and a cross-sectional size of 8.0 mm*2.35 mm continues to move forward and passes through the semi-finished product pass rolling mill 8 for semi-finished product pass rolling to obtain a semi-finished product steel wire 9 with a cross-sectional size of 8.0 mm*2.12 mm and a U-shaped groove section of 6.0 mm*0.6 mm; the U-shaped groove depth of the semi-finished product steel wire 9 is 60% of the U-shaped groove depth h of the finished steel wire (i.e., the U-shaped groove depth h of the finished steel wire is 0.9 mm); F. Secondary induction heating: The semi-finished steel wire 9 obtained in step E with a cross-sectional size of 8.0 mm*2.12 mm and a U-shaped groove cross-sectional size of 6.0 mm*0.6 mm continues to move forward and passes through the inner cavity of the induction heating device II 10 for secondary induction heating. The secondary induction heating temperature is 600° C., so as to soften the steel wire and increase the plastic toughness of the steel wire. G. Secondary high-pressure washing: After the secondary induction heating, the semi-finished steel wire 9 will form oxide scale on the surface. The semi-finished steel wire 9 continues to move forward and passes through the inner cavity of the high-pressure water tank II 11 to perform secondary high-pressure washing on the surface of the semi-finished steel wire, and the surface oxide scale is removed to obtain a clean semi-finished steel wire 9; H. Secondary drying: The semi-finished steel wire 9 with a clean surface obtained after the secondary high-pressure washing continues to move forward, passes through the inner cavity of the drying device II 12 to perform secondary drying on the semi-finished steel wire 9, evaporates the water remaining on the surface of the semi-finished steel wire, and obtains the semi-finished steel wire 9 with a dry surface; I. Finished product pass rolling: The semi-finished steel wire 9 with a dry surface and a cross-sectional size of 8.0 mm*2.12 mm and a U-shaped groove cross-sectional size of 6.0 mm*0.6 mm continues to move forward and passes through a finished product pass rolling mill 13 for finished product pass rolling to obtain a finished steel wire 14 with a cross-sectional size of 8.0 mm*2.0 mm and a U-shaped groove cross-sectional size of 6.0 mm*1.0 mm, thereby completing the forming of the U-shaped steel wire; J. Reeling and warehousing: As the wire take-up machine 15 rotates, the finished steel wire 14 with a cross-sectional size of 8.0 mm*2.0 mm and a U-shaped groove cross-sectional size of 6.0 mm*1.0 mm is wound onto the I-shaped wheel of the wire take-up machine 15 for reeling, and then packaged and warehousing is possible.

Claims

1. A method for forming a U-shaped steel wire for a circlip, characterized in that: The processing method is achieved by the following steps: A. Flat steel wire rolling: After the round steel wire (2) is unrolled by the pay-off device (1), it is first rolled by two rollers in a two-roll rolling mill (3) to obtain a flat steel wire (4); the cross-sectional width of the flat steel wire (4) is equal to the cross-sectional width (W) of the finished steel wire; B. First induction heating: the flat steel wire obtained in step A continues to move forward and passes through the inner cavity of the induction heating device I (5) for first induction heating. The first induction heating temperature is 500-600°C to soften the steel wire and increase its plastic toughness. C. First high-pressure flushing: After the first induction heating, the flat steel wire (4) will form an oxide scale on its surface. The flat steel wire (4) continues to move forward and passes through the inner cavity of the high-pressure water tank I (6) to perform the first high-pressure flushing on the surface of the flat steel wire, thereby removing the surface oxide scale to obtain a flat steel wire (4) with a clean surface. D. First drying: The flat steel wire (4) with a clean surface obtained after the first high-pressure washing continues to move forward and passes through the inner cavity of the drying device I (7) to perform the first drying on the flat steel wire (4), thereby evaporating the water remaining on the surface of the flat steel wire and obtaining a flat steel wire (4) with a dry surface; E. semi-finished product pass rolling: the flat steel wire (4) with a dry surface continues to move forward and passes through a semi-finished product pass rolling mill (8) to obtain a semi-finished product steel wire (9); the U-shaped groove depth of the semi-finished product steel wire (9) is 60% of the U-shaped groove depth (h) of the finished product steel wire; F. Secondary induction heating: the semi-finished steel wire (9) obtained in step E continues to move forward and passes through the inner cavity of the induction heating device II (10) for secondary induction heating. The secondary induction heating temperature is 500-600° C., so as to soften the steel wire and increase its plastic toughness. G. Secondary high-pressure washing: After the secondary induction heating, the semi-finished steel wire (9) will form an oxide scale on the surface. The semi-finished steel wire (9) continues to move forward and passes through the inner cavity of the high-pressure water tank II (11) to perform secondary high-pressure washing on the surface of the semi-finished steel wire, and the surface oxide scale is removed to obtain a semi-finished steel wire (9) with a clean surface. H. Secondary drying: The semi-finished steel wire (9) with a clean surface obtained after the secondary high-pressure washing continues to move forward and passes through the inner cavity of the drying device II (12) to perform secondary drying on the semi-finished steel wire (9), thereby evaporating the water remaining on the surface of the semi-finished steel wire to obtain a semi-finished steel wire (9) with a dry surface; I. Finished product pass rolling: the semi-finished steel wire (9) with a dry surface continues to move forward and passes through a finished product pass rolling mill (13) to be finished product pass rolling to obtain a finished steel wire (14), thereby completing the forming of the U-shaped steel wire; J. Rewinding and warehousing: As the wire take-up machine (15) rotates, the finished steel wire (14) is wound onto the I-shaped wheel of the wire take-up machine (15) for winding, and then packaged and warehousing.

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