A high-stress spring manufacturing process

Abstract

The application relates to a spring manufacturing process. The manufacturing process of a high-stress spring comprises the following steps: blanking; tip grinding; spring winding heating; quenching and tempering; strong pressure treatment; stress strong pressure; inner ring polishing; shot blasting treatment; surface treatment and detection packaging. The application provides a manufacturing process of a high-stress spring with high spring precision, no deformation in subsequent use and low scrap rate; and solves the technical problems of high spring scrap rate, insufficient precision and easy deformation in subsequent use in the spring manufacturing process in the prior art.

Description

Technical Field

[0001] This invention relates to a spring manufacturing process, and more particularly to a high-stress spring manufacturing process. Background Technology

[0002] Springs are crucial components in various mechanical equipment and devices. In recent years, with the increasing demands on spring performance from mainframe machines, high-stress springs have emerged. Generally, high-stress springs refer to hot-rolled cylindrical helical finite-life high-stress springs, with a minimum working stress greater than 950 MPa, a maximum working stress greater than 1500 MPa, and a fatigue life of no less than 100,000 cycles. Their main applications and products include: excavator track tension springs, bulldozer track tension springs, and paver track tension springs, etc.

[0003] However, due to manufacturing processes, high-stress springs often exhibit deviations in perpendicularity and straightness after production, resulting in a high scrap rate and deformation, causing load attenuation and preventing equipment from functioning properly. Summary of the Invention

[0004] This invention provides a manufacturing process for a high-stress spring that achieves high precision, does not deform during subsequent use, and has a low scrap rate; it solves the technical problems of high scrap rate, insufficient precision, and easy deformation during subsequent use in the existing spring manufacturing process.

[0005] The above-mentioned technical problem of the present invention is solved by the following technical solution: a manufacturing process for a high-stress spring, characterized by comprising the following steps:

[0006] a. Feeding materials;

[0007] b. Grind into a sharp point;

[0008] c. Spring heating;

[0009] d. The heated coil spring is wound into shape;

[0010] e. Quench the formed coil spring;

[0011] f. After quenching, the spring undergoes multi-stage tempering;

[0012] g. After tempering, the spring is subjected to high compression treatment, and the spring is compressed to the test load;

[0013] h. After strong compression, apply strong stress again to compensate for the deformation of the spring end ring and compress the spring to the yield load;

[0014] i. Grind the inner ring of the spring;

[0015] j. Perform shot blasting on the spring;

[0016] k. Surface treatment, testing, and packaging.

[0017] After a spring undergoes stress compression, because the maximum working stress exceeds the test stress, permanent deformation cannot be completely eliminated. Springs are special components, especially high-stress springs, which require a larger pre-fabrication height during manufacturing. For example, a certain high-stress spring has a material yield strength of 1650MPa, a maximum working stress of 1523MPa, a test stress of 890MPa, and a minimum working stress of 670MPa. The required finished height is 676mm. Before stress compression, the pre-fabrication height of the spring is 816mm, so the stress compression deformation is only about 60mm. If the spring had not undergone stress compression, it would still experience 80mm of permanent deformation during use, which is unacceptable for the product.

[0018] Stress compression treatment involves pressing the spring to the stress corresponding to the material's yield strength. After stress compression, the spring continues to deform by 80mm. The material's yield strength is greater than the maximum working stress, and the maximum working deformation during use is less than the stress compression deformation. The free height and performance are stable.

[0019] At the same time, during the stress-pressure treatment process, it can also correct geometric tolerances, such as perpendicularity and straightness, reducing the scrap rate of springs.

[0020] Preferably, the high-pressure treatment compresses the spring three times to eliminate a portion of the permanent deformation of the spring.

[0021] Preferably, the stress compression treatment involves compressing the spring three times to eliminate all permanent deformation of the spring.

[0022] Preferably, the shot blasting process includes shot blasting strengthening and hot shot blasting. The spring after shot blasting strengthening is very rough, while the surface after hot shot blasting is smoother.

[0023] More preferably, the hot shot blasting process involves heating the spring to 200℃-250℃, and the diameter of the steel shot used in the hot shot blasting is generally 0.5mm~0.7mm.

[0024] Preferably, the multi-stage tempering involves four tempering zones: zone one at T + (80-100)℃, zone two at T + (20-40)℃, and zones three and four at T℃. The value of T℃ is adjusted according to the product's hardness requirements. After tempering, rapid water cooling is performed to prevent tempering brittleness.

[0025] Preferably, before the inner ring grinding process, the spring is subjected to end face turning and flaw detection.

[0026] Preferably, before the stress is applied, the spring after the stress is applied is subjected to form and position tolerance testing, including testing the perpendicularity and straightness of the spring. Correction and compensation are performed during the stress application, and then the stress is applied.

[0027] Therefore, the manufacturing process of a high-stress spring of the present invention has the following advantages: the spring after being subjected to high stress compression can correct the poor perpendicularity and straightness of the spring caused by excessive deformation during one-time high stress compression; improve the stability of the spring and reduce the scrap rate of spring production. Detailed Implementation

[0028] The technical solution of the invention will be further described in detail below through examples.

[0029] Example:

[0030] A manufacturing process for a high-stress spring includes the following steps:

[0031] (1) Cutting: Cut the material into pieces using a saw according to the required length of the spring.

[0032] (2) Sharpening: The two ends of the bar are softened by electric heating in an induction furnace at a temperature of 950℃ for 1-5 minutes. Then, the softened ends are sharpened by a cone rolling mill.

[0033] (3) Spring heating: The bar stock is heated and softened by natural gas heating at a temperature of 920℃ and held for about 1-3 minutes.

[0034] (4) Rolling and forming: The hot spring coiling machine rolls the heated and softened bar material into shape according to the set processing parameters.

[0035] (5) Residual heat quenching: The rolled spring is quenched in a water bath and the spring is rapidly cooled to the specified temperature.

[0036] (6) Multi-stage tempering: The springs after quenching are sent into a continuous tempering furnace. The temperature of zone 1 is T+(80-100)℃, the temperature of zone 2 is T+(20-40)℃, and the tempering temperature of zones 3 and 4 is T℃. After tempering, the springs are rapidly water-cooled.

[0037] (7) High-pressure treatment: Compress the spring to the test load (the spring load corresponding to the test stress of 890MPa in the spring design standard GB / T23934), compress the spring 3 times to eliminate certain permanent deformation of the spring.

[0038] (8) Inspect the form and position tolerances of the spring after the high pressure treatment.

[0039] (9) Stress Compression: Based on the test results, adjust the spring compression device to compensate for the deformation of the spring end ring, correct the form and position tolerances, and then compress the spring to the yield load (yield load: the load corresponding to the minimum yield strength in the material standard GB / T 1222, for example, the yield strength of 40SiMnVBE material is ≥1680MPa, i.e., the spring corresponding to the minimum yield strength of 1680MPa). Compress the spring 3 times to eliminate all permanent deformation of the spring and ensure that the product meets the requirements after the spring durability test. The maximum working stress of the high-stress spring is less than the yield strength.

[0040] (10) End face turning: The two ends of the spring are turned to ensure the spring support surface, perpendicularity and flatness requirements.

[0041] (11) Flaw detection: The spring is tested by fluorescent magnetic particle testing to detect whether there are defects such as cracks and scratches on the surface.

[0042] (12) Inner ring grinding: Grind the inner ring of the spring to ensure that the spring is smooth and free of decarburization.

[0043] (13) Shot blasting: Shot blasting is used to bring the spring surface and the shallow layer at a specified depth to the required residual stress in order to improve the spring durability. The diameter of the steel shot used for shot blasting is generally Φ1.2-Φ1.4mm.

[0044] (14) Hot shot blasting: The spring is heated to 200-250℃ and then subjected to shot blasting treatment. After hot shot blasting, the roughness of the spring surface is further reduced, the surface stress is uniform, and the surface fatigue strength is further improved. The diameter of the steel shot used for hot shot blasting is generally Φ0.5-Φ0.7mm.

[0045] (15) Surface treatment: The spring surface is coated with anti-rust and anti-corrosion paint.

[0046] (16) Inspection: Spring size and performance inspection.

[0047] (17) Packaging: Spring packing for easy shipping.

[0048] The specific embodiments described herein are merely illustrative of the concept of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A manufacturing process for a high-stress spring, characterized in that: Includes the following steps: a. Feeding materials; b. Grind into a sharp point; c. Spring heating; d. Wind the heated coil spring into shape; e. Quench the formed coil spring; f. After quenching, the spring undergoes multi-stage tempering; g. After tempering, the spring is subjected to high compression treatment, and the spring is compressed to the test load; h. After strong compression, stress compression is performed again. Before stress compression, the spring after strong compression is subjected to form and position tolerance inspection, including the inspection of the spring's perpendicularity and straightness. Correction and compensation are performed during stress compression. Then stress compression is performed again to compensate for the deformation of the spring end ring and compress the spring to the yield load. i. Grind the inner ring of the spring; j. Perform shot blasting on the spring; k. Surface treatment, testing, and packaging.

2. The manufacturing process of a high-stress spring according to claim 1, characterized in that: The aforementioned high-pressure treatment compresses the spring three times, eliminating a portion of the spring's permanent deformation.

3. The manufacturing process of a high-stress spring according to claim 1, characterized in that: The stress compression treatment involves compressing the spring three times to eliminate all permanent deformation of the spring.

4. The manufacturing process of a high-stress spring according to claim 1, 2, or 3, characterized in that: The shot blasting process includes shot blasting strengthening treatment and hot shot blasting treatment.

5. The manufacturing process of a high-stress spring according to claim 4, characterized in that: The hot shot blasting process involves heating the spring to 200℃-250℃, and the diameter of the steel shot used in the hot shot blasting is generally 0.5mm~0.7mm.

6. The manufacturing process of a high-stress spring according to claim 1, 2, or 3, characterized in that: The multi-stage tempering process involves tempering in four tempering zones: zone one at T + (80-100)℃, zone two at T + (20-40)℃, and zones three and four at T℃. The value of T℃ is adjusted according to the product's hardness requirements. After tempering, the product is rapidly water-cooled.

7. The manufacturing process of a high-stress spring according to claim 1, 2, or 3, characterized in that: Before the inner ring grinding process, the spring is face-turned and inspected for defects.