PRODUCTION METHOD FOR BASEBALL BATS BASED ON 6-SERIES RECYCLED ALUMINUM

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims to the benefit of priority from Chinese Application No. 202411923324.2 with a filing date of Dec. 24, 2024. The content of the aforementioned applications, including any intervening amendments thereto, are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a production method for sports equipment, particularly a production method for baseball bats based on 6-series recycled aluminum.

BACKGROUND

At present, baseball bats are made by heating, melting, and casting 6061 alloy composed of pure aluminum ingots and Mg—Al intermediate alloys in a melting furnace. 6061 alloy aluminum is made by extrusion, drawing, solution treatment, and heat aging treatment. Its raw materials are mainly new aluminum ingots and intermediate alloy metals, which are more expensive than recycled aluminum metal.

With the development of the times and the dual carbon economy, in order to reduce costs and carbon emissions during product production, some manufacturers are currently manufacturing new baseball bats by recycling waste aluminum alloy baseball bats. However, the recycled aluminum alloy baseball bats contain more impurities, and remelting mainly faces the influence of relatively coarse Fe containing phases such as AlFeSi, AlFeMn, AlFeCr, etc. During extrusion and drawing processes, it is easy to cause surface cracks, poor tensile performance, and other problems, resulting in the inability to directly use remelted raw materials. This requires the addition of other alloys in the production process to eliminate the influence of relatively coarse Fe containing phases. For adding the composition and content of other alloys, precise analysis of the remelted raw materials is required, which undoubtedly increases the difficulty of processing.

SUMMARY

In order to overcome the shortcomings of existing technology, the present disclosure provides a production method for baseball bats based on 6-series recycled aluminum that no longer requires the addition of other alloys during the regeneration process, reduces production costs, and achieves energy conservation and emission reduction goals.

The technical solution adopted by the present disclosure to solve its technical problem is:

A production method for baseball bats based on 6-series recycled aluminum, which includes the steps as follows:

(1) Pre-treatment: peforming pre-treatment on waste aluminum alloy baseball bats to obtain recycled aluminum raw materials. The pre-treatment process includes well-known techniques in the art such as sorting, crushing, water washing, iron removal, paint removal, etc.

(2) Melting: putting the recycled aluminum raw materials into a melting furnace for melting, with a melting temperature of 700-750° C.; after the recycled aluminum raw materials are completely melted, removing the surface floating slag, then passing through the deep bed filtration and degassing process to obtain recycled aluminum liquid.

(3) Casting: allowing the recycled aluminum liquid to enter the electromagnetic casting crystallizer through a flow channel, and the recycled aluminum liquid is cast into a cast rod with a required diameter, wherein current turns of the electromagnetic casting crystallizer are 3000-8000 ampere-turns, the frequency is 0-100 Hz, and the diameter of the crystallizer is 150-200 mm.

(4) Homogenization treatment: performing two stage homogenization treatment on the cast rod, with the primary homogenization at the temperature of 520-550° C. and the time of 4-7 hours; and the secondary homogenization at the temperature of 550-570° C. and the time of 5-10 hours.

(5) Extrusion: heating the cast rod to 430-460° C., heating an extrusion mold to 420-450° C., with an extruding speed of 0.3-1 mm/s, and extruding the cast rod into a tubing with a desired diameter.

(6) Drawing: cutting the tubing into appropriate lengths, then placing the cut tubing in a drawing mold for drawing and stretching; heating the drawing mold during the drawing and stretching process, and achieve an initial shape of a finished product through multiple drawing processes, wherein the temperature of the drawing mold in the drawing process is 200-300° C., and the drawing speed is 0.3-1 mm/s.

(7) Subsequent processing: the subsequent processing is the same as the manufacturing process of baseball bats with new materials, which belongs to the routine techniques in the art.

The advantageous effects of the present disclosure are as follows: in the casting step, the crystallizer of the present application adopts electromagnetic stirring treatment to disperse Fe containing phases with larger sizes. In the homogenization treatment step, it is divided into two stages, the purpose of the primary homogenization treatment is to dissolve the Mg₂Si phase with a lower melting point into the matrix, and the purpose of the secondary homogenization treatment is to transform the elongated β-AlFeSi into spherical α-Al(FeMn)Si, eliminating harmful Fe phases. In the drawing step, the drawing mold is heated, and warm forming helps to make the aluminum alloy drawing smoother and reduce cracking. There is no need to add other alloys in the production process of recycled aluminum melting, which not only ensures performance, but also reduces production costs, achieving the goal of energy conservation, emission reduction, and recycling and reusing.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be further illustrated in conjunction with the accompanying drawings and embodiments.

FIG. 1 shows a photo of a cast rod without electromagnetic stirring.

FIG. 2 is a photo of the cast rod after drawing and stretching without electromagnetic stirring.

FIG. 3 is a photo of a cast rod with electromagnetic stirring.

FIG. 4 is a photo of the cast rod after drawing and stretching with electromagnetic stirring.

DETAILED DESCRIPTION OF THE EMBODIMENT

The applicant analyzed two batches of waste aluminum alloy baseball bat aluminum materials after remelting. The raw material recovery time of the two batches of aluminum materials differed by two months, and the composition is as follows:

The above analysis results indicate that the Al content in the recycled aluminum alloy baseball bat aluminum material reaches over 98%, and other components do not change much. Therefore, there is no need to consider the differences in raw materials during production.

A production method for baseball bats based on 6-series recycled aluminum includes the steps as follows:

(1) Pre-treatment: performing pre-treatment on waste aluminum alloy baseball bats to obtain recycled aluminum raw materials. The pre-treatment process includes well-known techniques in the art such as sorting, crushing, water washing, iron removal, paint removal, etc.

(2) Melting: putting the recycled aluminum raw materials into a melting furnace for melting, with a melting temperature of 700-750° C. (Generally, recycled baseball bats can be completely melted at 700° C., and there are no strict temperature requirements, this range is acceptable); after the recycled aluminum raw materials are completely melted, removing the surface floating slag, then passing through the deep bed filtration and degassing process to obtain recycled aluminum liquid (Aluminum slag removal, aluminum deep bed filtration, and aluminum degassing are well-known techniques in this field).

(3) Casting: allowing the recycled aluminum liquid to enter the electromagnetic casting crystallizer through a flow channel, and the recycled aluminum liquid is cast into a cast rod with a required diameter, wherein current turns of the electromagnetic casting crystallizer are 3000-8000 ampere-turns, the frequency is 0-100 Hz, and the diameter of the crystallizer is 150-200 mm (No strict requirements, this range is acceptable). FIG. 1 shows a photo of the cast rod without electromagnetic stirring (taken under a metallographic microscope), and FIG. 3 shows a photo of the cast rod with electromagnetic stirring (taken under a metallographic microscope). It can be seen from the figures that the black Fe containing second phase in the cast rod with electromagnetic stirring becomes fine and uniform under the action of electromagnetic stirring.

Electromagnetic casting crystallizer is a commonly used equipment in this field, which can be equipped with a frequency converter with a current turn of 1000-13000 ampere-turns and a frequency of 0-2100 Hz. The purpose of using electromagnetic stirring in this step is to disperse larger Fe containing phases into uniform and fine particles, avoiding agglomeration. The electromagnetic parameters of the crystallizer are closely related to the distribution and size of the Fe containing phase in the melt, and can also affect the forming of the final tubing product. When the Fe content in the ingot is high, setting the current turns too large can help to evenly disperse the Fe containing phase and reduce its size. However, setting the current turns too large can cause uneven crystallization of the melt or easily introduce gas, leading to casting defects. If the current turns are too small, it is not conducive to the fragmentation and distribution of the Fe containing phase. The frequency is generally related to the size of the crystallizer. The larger the diameter of the crystallizer, the smaller the frequency, and the larger the stirring area. The smaller the diameter of the crystallizer, the higher the frequency, and the smaller the stirring area. The selection of 3000-8000 ampere-turns and 0-100 Hz in this step can be adjusted according to actual needs, and the adjustment method belongs to the routine techniques in this field.

(4) Homogenization treatment: performing two stage homogenization treatment on the cast rod, with the primary homogenization at the temperature of 520-550° C. and the time of 4-7 hours; and the secondary homogenization at the temperature of 550-570° C. and the time of 5-10 hours. (The time and temperature for this step are not strictly required, and can be within this range). The purpose of the primary homogenization treatment is to dissolve the Mg₂Si phase with a low melting point into the matrix, while the purpose of the secondary homogenization treatment is to transform the elongated β-AlFeSi into spherical a-Al (FeMn) Si, eliminating harmful Fe phases. In this step, a long-term high-temperature two-stage homogenization treatment is adopted. During the homogenization treatment, Mn element directly participates in the phase transformation process of the iron rich phase, and the iron rich phase changes from the brittle β-AlFeSi phase in the lath shape to the spherical (granular) a-Al (FeMn) Si phase, avoiding problems such as surface cracks and poor tensile properties in the subsequent extraction process.

(5) Extrusion: heating the cast rod to 430-460° C., heating an extrusion mold to 420-450° C., with an extruding speed of 0.3-1 mm/s, and extruding the cast rod into a tubing with a desired diameter.

(6) Drawing: cutting the tubing into appropriate lengths, then placing the cut tubing in a drawing mold for drawing and stretching; heating the drawing mold during the drawing and stretching process, and achieve an initial shape of a finished product through multiple drawing processes, wherein the temperature of the drawing mold in the drawing process is 200-300° C., and the drawing speed is 0.3-1 mm/s. In this step, the drawing mold is heated to prevent the residual brittle Fe phase from affecting the surface during the homogenization process, which helps to make the aluminum alloy drawing smoother and reduce cracking. FIG. 2 shows a photo of the cast rod without electromagnetic stirring after drawing and stretching (taken with a regular digital camera), and FIG. 4 shows a photo of the cast rod with electromagnetic stirring after drawing and stretching (taken with a regular digital camera). It can be seen that the surface of the cast rod without electromagnetic stirring shows obvious cracks after drawing and stretching, while the surface of the cast rod with electromagnetic stirring is smooth without obvious cracks.

(7) Subsequent processing: the subsequent processing is the same as the manufacturing process of baseball bats with new materials, which belongs to the routine techniques in the art.

Conduct tensile tests under room temperature on five batches of aluminum materials prepared using the method described in this application. The equipment and standards used for the tests are: universal testing machine, model: CMT5504, execution standards: GB/T 228-2002. The experimental data is as follows:

The experimental data shows that the aluminum produced by the method of the present disclosure has good tensile strength, yield strength, and elongation, and its performance is very close to that of the brand new 6061 alloy aluminum. The method of the present disclosure for production process of recycled aluminum does not require the addition of other alloys during the smelting process, omitting the steps of analyzing the remelted raw materials and adding other alloys. The recycled waste aluminum alloy baseball bat can be directly remelted, and the performance of the baseball bat made from recycled aluminum can basically reach the performance of the baseball bat produced from brand new 6061 alloy aluminum, which can reduce production costs, reduce carbon emissions during the production process, and achieve the goal of energy conservation and emission reduction.

The above embodiments cannot limit the scope of the present disclosure. Any equal modifications and changes made by skilled person in the art without departing from the overall concept of the present disclosure still fall within the scope of the present disclosure.