A processing method for reducing the rejection rate of steel wheel rims

Abstract

The application discloses a kind of processing methods for reducing the scrap rate of steel rim, including slitting, circle, welding, weld treatment, cooling and flaring steps;The welding step: jaw distance L1=11.6+3.8×h, h is the thickness of steel plate;Flash voltage V, when rim diameter D>500mm, V is 8-14.5V, when D≤500mm, V is 3-5V;Flash allowance L2 is 4.5-9mm;Top forging allowance L3 is 3-8mm, top forging speed S is 30-50mm / s;Charged top end time is 0.1-0.5s.This method effectively reduces the rim quality problem and rework frequency caused by improper process through accurate control and optimization of key process of rim processing, shortens production cycle, improves overall production efficiency, reduces production cost, significantly improves the processing quality of steel rim, significantly reduces the scrap rate of steel rim.After actual production verification, the processing scrap rate of steel rim is reduced to less than 5‰ from 1%-2% of traditional method.

Description

Technical Field

[0001] This invention relates to the field of steel rim processing technology, and in particular to a processing method for reducing the scrap rate of steel rims. Background Technology

[0002] In the production of steel rims, the complexity of the processing technology and the high requirements for product quality have always resulted in a high scrap rate, a key constraint affecting production efficiency and cost. Traditional steel rim processing methods have numerous problems. For example, in the slitting process, microscopic cracks on the sheared surface are inevitable due to defects in the shearing machine. If the quality of the sheared surface is not properly controlled, it will lead to unstable subsequent processing quality. During the circling process, improper placement of the bright band on the sheared surface can easily cause stress concentration, reducing rim strength and causing processing cracks. Inappropriate welding parameters make it difficult to guarantee weld quality, easily leading to defects such as incomplete welds and cracks. Insufficiently refined weld treatment processes result in residual weld slag and uneven welds that affect the overall quality of the rim. Furthermore, the lack of a cooling process before forming or the poor selection of cooling media and conditions fails to effectively eliminate welding stress. Inappropriate control of the flaring elongation rate during the flaring process leads to non-compliant rim end dimensions and shapes, and amplifies quality defects on the sheared surface. These problems combined result in a high scrap rate for steel rims during production.

[0003] Current research on wheel rim scrap rates focuses on material optimization and welding process improvement, while insufficient attention is paid to key processes in the overall wheel rim manufacturing process. This limits the further improvement of wheel rim processing yield, not only wasting a large amount of raw materials and energy and increasing production costs, but also reducing the market competitiveness of enterprises. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a processing method for reducing the scrap rate of steel rims, so as to improve the processing quality of steel rims.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention includes the steps of cutting, circling, welding, weld treatment, cooling and flaring. The welding steps are as follows: jaw distance L1 = 11.6 + 3.8 × h, where h is the steel plate thickness; flash voltage V, when the rim diameter D > 500 mm, V is 8 ~ 14.5 V, when D ≤ 500 mm, V is 3 ~ 5 V; flash allowance L2 is 4.5 ~ 9 mm; upsetting allowance L3 is 3 ~ 8 mm; upsetting speed S is 30 ~ 50 mm / s. The weld treatment steps are as follows: the slag removal height h1 is 0.3-0.5mm higher than the base material, and the flattening height h2 is 0.05-0.1mm higher than the base material; The cooling step involves cooling with an oil-water mixture, wherein the ratio of oil to water is 1:(35-45). The flaring step: the flaring elongation δ is controlled between 6.6% and 12%.

[0006] Furthermore, in the welding step, the energized tip time is 0.1 to 0.5 seconds.

[0007] Furthermore, the cooling step involves using an oil-water mixture at a temperature of 20–50°C.

[0008] Furthermore, the circular rolling step involves rolling the rectangular strip into a circle, with the bright band of the cut surface positioned on the outer circle.

[0009] Furthermore, the slitting step involves cutting the raw material steel plate into rectangular strips, with the thickness of the bright band on the cut surface not less than 1 / 3 of the steel plate thickness.

[0010] The beneficial effects of adopting the above technical solution are as follows: By precisely controlling and optimizing key processes in wheel rim processing, this invention effectively reduces wheel rim quality problems and rework caused by improper processes, shortens the production cycle, improves overall production efficiency, reduces production costs, significantly improves the processing quality of steel wheel rims, and significantly reduces the scrap rate of steel wheel rims. Actual production verification shows that after adopting the processing method of this invention, the scrap rate of steel wheel rims has been reduced from 1%–2% using traditional methods to below 5‰. Attached Figure Description

[0011] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0012] Figure 1 This is an image of the bright band on the sheared surface described in this invention; Figure 2 This is a schematic diagram showing the position of the bright band after the circle is formed, as described in this invention. Figure 3 This is a photograph of the finished wheel rim product described in this invention.

[0013] In the diagram: Bright band 1; Tear band 2. Detailed Implementation

[0014] This processing method for reducing the scrap rate of steel wheel rims includes the following steps: slitting, rounding, welding, weld treatment, cooling, flaring, rolling, and expansion; the process of each step is described below: S1. Slitting: The raw steel plate is cut into strips according to design requirements to obtain rectangular strips; the quality of the sheared surface is strictly controlled. Figure 1 , Figure 2As shown, two cross-sectional features will be formed during the shearing process: bright band 1 and tear band 2; ensure that the thickness of the bright band is not less than 1 / 3 of the steel plate thickness, that is, the thickness of the bright band d≥1 / 3×h, where h is the steel plate thickness in mm.

[0015] S2, Circling: Roll the rectangular strip into a circle, with the bright band 1 on the sheared surface positioned on the outer circle and the tear band 2 positioned on the inner circle, such as... Figure 2 As shown. In this way, by precisely controlling the thickness and position of the bright band 1, stress concentration can be effectively reduced, the overall strength of the rim can be improved, and defects such as cracking due to stress problems can be avoided during subsequent use.

[0016] S3. Welding: Use a flash welding machine to weld the ring-shaped interface. The welding parameters are as follows: the jaw distance L1 is determined by the steel plate thickness h: L1 = 11.6 + 3.8 × h; the flash voltage V is determined by the rim diameter D: when D > 500 mm, V is 8 ~ 14.5 V, and when D ≤ 500 mm, V is 3 ~ 5 V; the flash allowance L2 is 4.5 ~ 9 mm; the upsetting allowance L3 is 3 ~ 8 mm; the upsetting speed S is 30 ~ 50 mm / s; and the energized tip time is 0.1 ~ 0.5 s.

[0017] S4. Weld treatment: The weld is treated by slag removal, flattening, and end cutting; the height of the slag removal above the base material (i.e., the slag height h1) is 0.3-0.5 mm, and the height of the flattening above the base material (i.e., the flattening height h2) is 0.05-0.1 mm, to ensure a smooth weld surface and provide allowance for subsequent processing.

[0018] S5. Cooling: Immerse the workpiece in an oil-water mixture at 20-50°C for cooling; the oil-water mixture uses mineral oil, and the volume ratio of mineral oil to water is 1:(35-45), preferably 1:40. Such a cooling medium and temperature conditions can effectively eliminate welding stress, prevent weld cracks due to stress concentration, and avoid changes in material properties caused by improper cooling, thus ensuring the quality stability of the rim.

[0019] S6. Flaring: Flaring both ends of the cooled workpiece to the designed angle and diameter; Flaring elongation δ (%) = (D1×π-L) / L, where D1 is the diameter of the rim after flaring in mm, and L is the length of the rectangular strip after slitting in mm; control the flaring elongation δ between 6.6% and 12% to prevent edge cracking caused by unreasonable flaring process.

[0020] S7. Roll forming: The flared workpiece is rolled at least three times to form key structures, such as tire bead seats and wheel flanges.

[0021] S8. Expansion: The rolled workpiece is expanded and shaped to form a rim, such as... Figure 3 As shown.

[0022] Examples 1-6: Production was carried out according to the above methods and steps.

[0023] The following equipment is used: one shearing machine, one rounding machine (with flattening), one butt welding machine, one slag remover, one rolling press, one end cutting machine, one flaring machine, three rolling forming machines, and one hydraulic press (expansion).

[0024] The key process parameters and processing scrap rates for Examples 1-6 are shown in Table 1; Table 1: Process parameters and scrap rates for each embodiment

[0025] In Table 1, the scrap rate is the scrap rate statistically calculated after the process of each embodiment is implemented in large quantities.

Claims

1. A processing method for reducing the scrap rate of steel wheel rims, characterized in that: This includes the steps of cutting, circling, welding, weld treatment, cooling, and flaring. The welding steps are as follows: jaw distance L1 = 11.6 + 3.8 × h, where h is the steel plate thickness; flash voltage V, when the rim diameter D > 500 mm, V is 8 ~ 14.5 V, when D ≤ 500 mm, V is 3 ~ 5 V; flash allowance L2 is 4.5 ~ 9 mm; upsetting allowance L3 is 3 ~ 8 mm; upsetting speed S is 30 ~ 50 mm / s. The weld treatment steps are as follows: the slag removal height h1 is 0.3-0.5mm higher than the base material, and the flattening height h2 is 0.05-0.1mm higher than the base material; The cooling step involves cooling with an oil-water mixture, wherein the ratio of oil to water is 1:(35-45). The flaring step: the flaring elongation δ is controlled between 6.6% and 12%.

2. The processing method for reducing the scrap rate of steel wheel rims according to claim 1, characterized in that: The welding step involves energizing the tip for 0.1 to 0.5 seconds.

3. The processing method for reducing the scrap rate of steel wheel rims according to claim 1, characterized in that, The cooling step involves using an oil-water mixture at a temperature of 20–50°C.

4. The processing method for reducing the scrap rate of steel wheel rims according to claim 1, characterized in that, The circular rolling step involves rolling a rectangular strip into a circle, with the bright band of the cut surface positioned on the outer circle.

5. A processing method for reducing the scrap rate of steel wheel rims according to any one of claims 1-4, characterized in that, The cutting step involves cutting the raw steel plate into rectangular strips, with the thickness of the bright band on the cut surface not less than 1 / 3 of the steel plate thickness.

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