METHOD OF MANUFACTURING OF FORGED ALUMINUM WHEEL

Abstract

The present disclosure relates to a manufacturing method of an aluminum forging wheel, the manufacturing method being able to homogenize a material, optimize flow ability, prevent picking inside a wheel, and densify the internal structure of an aluminum forging wheel. The manufacturing method of an aluminum forging wheel includes: a billet preparation step S1 of preparing an aluminum billet to manufacture an aluminum forging wheel; a first forming step S2 of manufacturing a primary forming product by performing hot forging on the billet prepared in the billet preparation step S1; a second forming step S3 of manufacturing an aluminum forging wheel that is a secondary forming product by performing hot forging on the primary forming product manufactured in the first forming step S2; and a second machining step S5 of preheating the aluminum forging wheel manufactured in the first forming step S3 and performing F/F.

Claims

1. A manufacturing method of an aluminum forging wheel, comprising the steps of: S1: preparing an aluminum billet to manufacture said aluminum forging wheel; S2: performing hot forging on said aluminum billet of said step S1 to obtain a primary forming product; S3: performing hot forging on the primary forming product of said step S2 to obtain a secondary forming product; and S5: preheating the secondary product of said step S3 and performing flow forming; wherein said step S2 comprises the steps of: S2-1: preheating said aluminum billet of said step S1 in a preheating furnace; S2-2: preheating a first mold for manufacturing said aluminum forging wheel; and S2-3: manufacturing said primary forming product by performing hot forging one time at a pressure over 4,000 tons and under 6,000 tons through a forging machine.

2. The manufacturing method of claim 1, further comprising the step of: S4: trimming and diameter-enlarging said secondary forming product of said step S3 and performing pre-NC machining after said step S3; wherein said step S5 is performed after said step S4.

3. The manufacturing method of claim 1, wherein said step S1 comprises the steps of: S1-1: providing an aluminum billet; S1-2: cutting said aluminum billet to correspond to a volume of said aluminum forging wheel; and S1-3: feeding said aluminum billet of said step S1-2 into a preheating furnace.

4. The manufacturing method of claim 1, wherein said step S3 comprises the steps of: S3-1: preheating the primary forming product of said step S2 in a preheating furnace; S3-2: preheating a second mold for manufacturing the aluminum forging wheel; and S3-3: manufacturing said secondary forming product by performing hot forging one time at a pressure over 6,000 tons and under 10,000 tons through a forging machine.

5. The manufacturing method of claim 1, wherein said preheating of said step S2-1 is within 400-510° C.; and said preheating of said step S2-2 is within 300-430° C.

6. The manufacturing method of claim 4, wherein said preheating of said step S3-1 is within 400-510° C.; and said preheating of said step S3-2 is within 300-430° C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a picture when a billet was cut smaller than the volume of an aluminum wheel and then forged;

[0020] FIG. 2 is a picture when preheating was performed out of a preheating temperature range of a billet and then forged;

[0021] FIG. 3 is a picture when preheating was performed out of a preheating temperature range of a mold and then forged;

[0022] FIG. 4 is a picture when forging was performed at a forging pressure below reference in first forming;

[0023] FIG. 5 is a picture when forging was performed at a forging pressure below reference in second forming;

[0024] FIG. 6 is a picture of an aluminum wheel before pre-NC machining;

[0025] FIG. 7 is a picture of an aluminum wheel after pre-NC machining;

[0026] FIG. 8 is a picture when preheating was performed out of a preheating temperature of step S5 and then flow forming was performed;

[0027] FIG. 9 is a picture when preheating was performed within a preheating temperature of step S5 and then flow forming was performed;

[0028] FIG. 10 is a picture of an embodiment of flow forming; and

[0029] FIG. 11 is a flowchart of a manufacturing method of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

[0030] The present disclosure relates to a manufacturing method of an aluminum wheel that includes: a billet preparation step S1 of preparing an aluminum billet to manufacture an aluminum forging wheel; a first forming step S2 of manufacturing a primary forming product by performing hot forging on the billet prepared in the billet preparation step S1; a second forming step S3 of manufacturing an aluminum forging wheel that is a secondary forming product by performing hot forging on the primary forming product manufactured in the first forming step S2; a first machining step S4 of trimming and diameter-enlarging the aluminum forging wheel manufactured in the second forming step S3 and of performing pre-NC machining S4; and a second machining step S5 of preheating the aluminum forging wheel manufactured in the second forming step S3 and of performing flow forming. The steps are described hereafter in detail with the drawings.

[Billet Preparation Step S1]

[0031] The billet preparation step S1 of the present disclosure, as indicated by S1-1 to S1-3 in FIG. 11, is a step of providing S1-1 a billet, cutting S1-2 the provided billet into the size of an aluminum wheel to be manufactured, and feeding S1-3 the billet into a preheating furnace to preheat the billet.

[0032] In the cutting S1-2 of the billet, the volume of an aluminum wheel to be manufactured is calculated and then the billet is cut to correspond to the volume.

[0033] When the billet is cut smaller than the volume of an aluminum wheel to be manufactured, incomplete forming occurs due to shortage of material, so, as shown in FIG. 1, the end of the rim is not fully filled, whereby an aluminum wheel is not formed in a complete shape.

[0034] Next, the billet cut as described above is fed S1-3 into a preheating furnace for forging.

[First Forming Step S2]

[0035] The first forming step S2 of the present disclosure, which is indicated by S2-1 to S2-3 in FIG. 11, is to forge the billet prepared in the billet preparation step S1.

[0036] First, the billet fed into the preheating furnace in the billet preparation step S1 is preheated up to a temperature of 400-510° C. (S2-1).

[0037] Preheating the billet in this way is for homogenizing the material and optimizing flow stress. When a temperature comes out of the preheating temperature range (400-510° C.) of the billet, as shown in FIG. 2, a product is not completely formed due to shortage of fluidity of a material in forming.

[0038] Next, a mold is preheated up to 300-430° C. before forging (S2-2).

[0039] The reason of preheating the mold into the temperature range is because when a temperature exceeds or does not reach the temperature range, as shown in FIG. 3, the billet in the temperature range of 400-510° C. is burned on the mold and is not taken out or forming is not completely performed due to non-uniform flow of the material.

[0040] Next, first forming is performed after the billet is preheated and the mold is preheated (S2-3).

[0041] The first forming is performed by performing hot forging one time through a forging machine over 4,000 tons and under 6,000 tons. The purpose of the first forming is to uniformly distribute the billet before the second forming. In this case, when the pressure is under 4,000 tons, metal flow is stopped due to shortage of pressure, so non-forming is generated, and as shown in FIG. 4, the structure in the aluminum alloy is not densified.

[Second Forming Step S3]

[0042] The second forming step S3 of the present disclosure, which is indicated by S3-1 to S3-3 in FIG. 11, is performed under the same conditions as the first forming step S2.

[0043] That is, the product first formed through the first forming step S2 is preheated up to 400-510° C. in the preheating furnace (S3-1) and a mold for second forming is preheated up to 300-430° C. (S3-2). Then, forging is performed one time through a forging machine over 6,000 tons and under 10,000 tons (S3-3).

[0044] The purpose of the second forming is to forge the billet into a final aluminum wheel shape. In this case, when the pressure is under 6,000 tons, the structure in the aluminum alloy is not densified due to shortage of pressure, so, as shown in FIG. 5, a narrow and dense shape is not completely formed, whereby a spoke may not be formed.

[First Machining Step S4]

[0045] The first machining step S4 of the present disclosure, which is indicated by S4-1 to S4-2 in FIG. 11, is a step of machining the aluminum wheel manufactured in the second forming step.

[0046] The first machining step S4 in the present disclosure is not necessary, and it is possible to achieve the objectives of the present disclosure even by performing only the second machining step.

[0047] The first machining step S4 performs trimming of removing an unnecessary material from the aluminum wheel manufactured in the second forming step S3, and enlarges the diameter of the rim for smooth flow forming (F/F) in the next step (S4-1).

[0048] Next, pre-NC is performed on the aluminum wheel trimmed and diameter-enlarged to stably secure the product in flow forming (F/F) and achieve a uniform rim thickness (S4-2).

[0049] The reason of performing pre-NC is for improving stability of seating and making the thickness of the rim uniform because only hot forging is performed in the first forming step S2 and the second forming step S3, so an aluminum wheel completed through only hot forging has a rough surface so as not to be stably seated and has an ununiform rim thickness.

[0050] FIG. 6 is a picture of an aluminum wheel before pre-NC machining and FIG. 7 is a picture of an aluminum wheel after pre-NC machining.

[Second Machining Step S5]

[0051] The second machining step S5 of the present disclosure, which is indicated by S5-1 to S5-2 in FIG. 11, may be performed after the first machining step S4 or may be performed after the second forming step S3 without performing the first machining step S4.

[0052] The second machining step S5 is started with preheating the aluminum wheel (S5-1) formed in the second forming step S3. In this case, a preheating condition is to preheat the aluminum wheel up to 360-380° C. slightly lower than the preheating temperature in the first forming step S2 and the second forming step S3 (S5-1).

[0053] When the second machining step S5 is performed after the first machining step S4, the aluminum wheel machined through the first machining step S4 is preheated (S5-1).

[0054] This is because when preheating is performed within the temperature range described above, fluidity of the material can be optimally maintained in flow forming (F/F).

[0055] As shown in FIG. 8, when a temperature comes out of the temperature range below the lower limit of the temperature range, non-forming may be generated, and when the temperature exceeds the temperature range, a wheel is twisted.

[0056] FIG. 9 is a picture showing an aluminum wheel that has undergone flow forming (F/F) after preheating within the temperature range.

[0057] After the preheating step S5-1, flow forming (F/F) S5-2 is performed. flow forming (F/F), as shown in FIG. 5, is to make the particles of a structure fine and dense by applying forced rolling on a rim, whereby higher rigidity, strength, and shock resistance are achieved.

[Post-Processing Step]

[0058] According to the present disclosure, an aluminum forging wheel is manufactured through the billet preparation step S1 to the second machining step S5, as described above.

[0059] After the second machining S5, examining, heat treatment, machining, and painting may be performed as post-processing steps.

[0060] The examining step, which is for checking cracks, defects, etc. that may exist on the surface of the forged aluminum wheel, may be performed through common fluorescent penetrant inspection (fluorescent penetration, penetration test).

[0061] The heat treatment step is to perform heat treatment on the aluminum wheel manufactured through the steps described above. In this case, it is preferable that the heat treatment is performed in a T6 type that performs artificial aging after solution treatment.

[0062] The machining step machines the rim to form a portion on which a tire is seated and a portion that is mounted on the hub of a vehicle.

[0063] Finally, the painting step may be selected from various common painting methods.

[0064] As described above, the present disclosure was described through embodiments with reference to the accompanying drawings, but the embodiments are preferred embodiment, so the present disclosure is not limited to the embodiments, and the protection range of the present disclosure should be understood as the following claims and an equivalent concept.

[0065] The present disclosure can manufacture an aluminum wheel by homogenizing an aluminum wheel and optimizing flow ability by preheating a material up to a predetermined temperature when manufacturing an aluminum wheel.

[0066] Further, the present disclosure can increase formability by solving problems such as material burning on a mold by maintaining a mold at a predetermined temperature in forging.

[0067] Further, the present disclosure can densify the alloy structure in an aluminum wheel by performing hot forging two times.

[0068] Further, the present disclosure can manufacture an aluminum forging wheel that provides high rigidity, strength, and shock resistance by making structure particles fine and dense by applying forced rolling on a rim in the step of flow forming.

[0069] While the present invention has been described with respect to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.