JPWO2018235902A1 - Zinc-based alloy shot and method for producing the same - Google Patents

Abstract

The zinc-based alloy shot, wherein the zinc-based alloy shot is composed of Al and the balance Zn and unavoidable impurities, and the content of Al relative to the zinc-based alloy shot is 1.0 to 6.0% by mass. The zinc-based alloy shot has a Vickers hardness of 50 to 100 HV. Further, Cu may be further added as a trace additive element to the zinc-based alloy shot, and the addition amount of the trace additive element may be 0.0001 to 0.25 mass% with respect to the zinc-based alloy shot. Good.

Description

  The present invention relates to a zinc-based alloy shot used for blasting and a method for manufacturing the same.

  Blasting has been known for a long time in which particles called shots are collided with an object to be processed and surface treatment (burrs removal, rounding (Ring), surface roughness adjustment, satin processing, etc.) of a work is performed. The material of the shot is selected according to the material of the work and the processing purpose. For example, in the case of blasting a die-cast product made of an aluminum alloy, a magnesium alloy, or a zinc alloy, zinc shot is selected in consideration of scouring ability and dust explosion resistance.

  Patent Document 1 discloses a shot made of zinc. Since this shot has a Vickers hardness of 40 to 50 HV (specified in JIS Z2244), the scouring and cleaning ability is low.

  Therefore, shots made of zinc alloy have been developed. For example, Patent Document 2 discloses a shot of a zinc-based alloy made of Zn-Mn. However, Mn is a target of the PRTR system and is not preferable from the viewpoint of safety and environmental protection.

JP-A-63-312067 JP 2001-162538 A

  In view of the above, it is an object of the present invention to provide a new zinc-based alloy shot having a high scouring ability and a long life, and a method for producing the same.

According to the present invention, the following zinc-based alloy shot and its manufacturing method are provided.
[1] Zinc-based alloy shot,
The zinc-based alloy shot comprises Al and the balance Zn and inevitable impurities,
The content of Al with respect to the zinc-based alloy shot is 1.0 to 6.0 mass%,
A zinc-based alloy shot, wherein the zinc-based alloy shot has a Vickers hardness of 50 to 100 HV.
[2] The zinc-based alloy shot according to item 1, wherein the zinc-based alloy shot has a Vickers hardness of 50 to 90 HV.
[3] Previously, the zinc-based alloy shot further contains Cu as a trace additive element,
The zinc-based alloy shot according to item 1 or 2, wherein the addition amount of the trace additive element is 0.0001 to 0.25 mass% with respect to the zinc-based alloy shot.
[4] The zinc-based alloy shot is a granular material having a diameter of 0.2 to 2.0 mm, or (1: 0.8) ≦ (diameter: length) ≦ (1: 1.3) The zinc-based alloy shot according to any one of 1 to 3, which is a cylinder having a ratio of.
[5] The zinc-based alloy shot is a granular material, and when the length in the longitudinal direction of the shot obtained from the projected view is a and the maximum diameter in the direction orthogonal to the longitudinal direction is b, the shot is 60% or more. The zinc-based alloy shot according to any one of items 1 to 4, wherein a / b of the shot is in the range of 1.0 to 1.3.
[6] The method for producing a zinc-based alloy shot according to any one of 1 to 5 above,
A step of weighing Zn, Al that is a raw material metal, and Cu if necessary,
A step of heating the raw material metal to form a molten metal;
A step of transferring the molten metal to a molten metal holding container having a nozzle arranged at the bottom,
A step of dropping the molten metal into a liquid cooling medium through the nozzle;
A step of solidifying the molten metal in the cooling medium to obtain a granular body,
A step of classifying the granular material into a predetermined size,
Including,
In the classification step, the diameter of the solidified molten metal is classified to 0.2 to 2.0 mm, and the zinc-based alloy shot manufacturing method.
[7] A method for producing a zinc-based alloy shot according to any one of the above items 1 to 4,
A step of obtaining a lump having an alloy composition of Zn, Al that is a raw material metal, and optionally Cu,
Obtaining a wire having a predetermined diameter from the lump,
Cutting the wire into a predetermined length,
Including,
In the step of obtaining the wire, the method for producing the zinc-based alloy shot, which includes a step of rolling a lump and applying stress.
[8] In the step of cutting the wire, the wire is cut so that (1: 0.8) ≦ (wire diameter: wire length) ≦ (1: 1.3), A method for producing the zinc-based alloy shot as described.
[9] The method for producing a zinc-based alloy shot according to the above 7 or 8, wherein in the step of obtaining the wire, the lump is processed so that the diameter of the wire is 0.4 to 2.0 mm.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a zinc-based alloy shot having a high scouring ability and a long life. By including a predetermined amount of Cu, it is possible to provide a zinc-based alloy shot that not only suppresses the darkening of the work but also improves the scouring and cleaning ability, the life, and the tensile strength.

It is a flow chart for explaining one embodiment of the manufacturing method of the zinc basis alloy shot of the present invention. 3 is a flowchart for explaining another embodiment of the method for manufacturing a zinc-based alloy shot of the present invention.

  One aspect of the present invention is a zinc-based alloy shot. The zinc-based alloy shot contains Al and the balance Zn and unavoidable impurities. The Al content with respect to the zinc-based alloy shot is 1.0 to 6.0 mass%. The Vickers hardness of the zinc-based alloy shot is 50 to 90 HV.

  Since Al is added to the zinc-based alloy shot of one aspect of the present invention, it has a higher hardness and a higher scouring ability than zinc. Further, since the impact resistance (toughness) is improved, the life is long. Since Al is relatively inexpensive, it is possible to inexpensively produce a zinc-based alloy shot having a high scouring ability and a long life.

  In one embodiment of the present invention, Cu may be further added to the zinc-based alloy shot as a trace additive element. Then, the addition amount of the trace addition element may be 0.0002 to 0.25 mass% with respect to the shot of the zinc-based alloy. By adding a trace amount of Cu, it is possible to suppress the occurrence of darkening during blasting.

Another embodiment of the invention is a zinc based alloy shot,
The zinc-based alloy shot is composed of Al, Cu as a trace additive element, Zn as the balance and unavoidable impurities,
The content of Al with respect to the zinc-based alloy shot is 1.0 to 6.0 mass%,
The content of Cu with respect to the zinc-based alloy shot is 0 to 0.25% by mass,
The zinc-based alloy shot is a granular body having a diameter of 0.2 to 2.0 mm, or a ratio of (1: 0.8) ≦ (diameter: length) ≦ (1: 1.3) is satisfied. Is a cylinder having
It is the said zinc base alloy shot whose Vickers hardness of the said zinc base alloy shot is 50-90 HV.

One embodiment of the present invention is a method of making a zinc-based alloy shot. This manufacturing method may include the following steps (1) to (6).
(1) A step of weighing Zn, Al that is a raw material metal, and Cu if necessary.
(2) A step of heating the raw material metal to form a molten metal.
(3) A step of transferring the molten metal to a molten metal holding container having a nozzle arranged at the bottom.
(4) A step of dropping the molten metal into a liquid cooling medium via a nozzle.
(5) A step of solidifying the molten metal in a cooling medium to obtain a granular body.
(6) A step of classifying the granular material into a predetermined size.
Then, in the step (6), the particles may be classified to have a diameter of 0.2 to 2.0 mm. In addition, in this specification, a "diameter" means a diameter.

  The fluidity of the molten metal is improved by containing Al. Therefore, the nozzle can be satisfactorily dropped without being clogged with the molten metal. Further, if the diameter of the granules is 0.2 to 2.0 mm, granules having a relatively uniform shape can be obtained.

One embodiment of the present invention is a method of making a zinc-based alloy shot. This manufacturing method may include the following steps (11) to (13).
(11) A step of obtaining a lump having an alloy composition of Zn, Al that is a raw material metal, and optionally Cu.
(12) A step of obtaining a wire having a predetermined diameter from the lump.
(13) A step of cutting the wire into a predetermined length.
Then, the step of obtaining the wire may include the step of rolling the lump and applying stress.

  The inclusion of Al improves the toughness of the alloy. As a result, when the lump is rolled and processed into a wire, it is not broken during the processing. Furthermore, by applying stress to the wire when rolling the lump, the mechanical properties are improved.

  According to an embodiment of the present invention, in the step of obtaining the wire, the lump is processed so that the diameter of the wire is 0.4 to 2.0 mm, and in the step of cutting the wire, (1: 0.8) ≦ (Wire diameter: wire length) ≤ (1: 1.3) or (1: 0.8) ≤ (wire diameter: wire length) ≤ (1: 1.2) ), The wire may be cut. When the diameter of the wire is 0.4 mm or more, it is possible to obtain the wire having the mechanical strength required for the blasting. Further, if the diameter is 2.0 mm or less, for example, even when a relatively soft work such as an aluminum die cast product is blasted, the work is not damaged more than necessary. Then, by cutting the wire so that the ratio of the diameter and the length of the cut wire is within this range, it is possible to perform blasting with little variation in finished quality.

  An embodiment of the zinc-based alloy shot and the method for producing the same of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiment, and can be appropriately changed within an equivalent range. Further, in the following description, “%” indicating the alloy composition indicates “mass%” unless otherwise specified.

  The zinc-based alloy shot of one embodiment contains Al. Al has a synergistic effect with Zn to improve the Vickers hardness and impact resistance (toughness) of the zinc-based alloy. If the Al content is too low, the effect of addition cannot be obtained. If it is too large, the influence of the physical properties of Al becomes too strong, and the impact resistance of the zinc-based alloy tends to decrease. In one embodiment, the content of Al (100% basis of the total amount: the same applies hereinafter) is 1.0 to 6.0%, and may be 1.3 to 5.8%, or 2.9 to 5. It may be 6%.

  Cu is an element added as necessary to improve the corrosion resistance of shots of the zinc-based alloy. As a result of the improved corrosion resistance, it is possible to suppress the occurrence of darkening on the surface of the work when the blasting is performed using this zinc-based alloy shot. However, if Cu is excessively added, the impact resistance of the shot of the zinc-based alloy is lowered, so that the addition amount is preferably small. In one embodiment, the added amount of Cu (100% basis of the total amount: the same applies hereinafter) is 0 to 0.25%, and may be 0.0001 to 0.25% or 0.0002 to 0.25. Or may be 0.0002 to 0.05%.

  Cu also has an effect of improving the Vickers hardness and impact resistance of the zinc-based alloy shot. The addition of a small amount of Cu has not only the effect of suppressing the occurrence of darkening on the work described above, but also the effect of further improving the scouring / cleaning ability of zinc-based alloy shots and the life.

  Zinc-based alloy shots are also used for workpieces with relatively low hardness, such as die cast products composed of aluminum alloys, magnesium alloys, and zinc alloys. If the hardness of the shot of the zinc-based alloy is too low, the workability of the work is insufficient, and if it is too hard, the design of the surface of the work is affected. In consideration of the physical properties of the work and the purpose of blasting, the Vickers hardness of the shot of the zinc-based alloy may be 50 to 100 HV, 50 to 90 HV, or 70 to 90 HV, and the Vickers hardness may be set to Al so that the hardness becomes Al. The content of Cu or the amount of Cu added may be adjusted.

  The zinc-based alloy shot of one embodiment is composed of Zn and Al, or Zn and Al and a trace amount of Cu, but may contain other unavoidable impurities. However, when the content of unavoidable impurities is high, the impact resistance is low and the life is shortened. Therefore, it is desirable that the total content of unavoidable impurities is as small as possible.

The content of Al with respect to the shot of the zinc-based alloy is 1.0 to 6.0%,
The content of Cu with respect to the shot of the zinc-based alloy is 0.0001 to 0.25 mass%,
A zinc-based alloy shot having a Vickers hardness of the zinc-based alloy shot of 50 to 100 HV is particularly preferable.

The content of Al with respect to the shot of the zinc-based alloy is 1.3 to 5.8%,
The content of Cu with respect to the zinc-based alloy shot is 0.0002 to 0.05 mass%,
The zinc-based alloy shot having a Vickers hardness of 70 to 90 HV is even more preferable.

  Next, a method of manufacturing a zinc-based alloy shot according to one embodiment will be described below with reference to FIG.

S01: Step of weighing raw materials Weigh metal serving as raw materials. For example, as a raw material (ingot) of Al, aluminum ingot special type 1 of JIS H2102 (99.90% or more) or refined aluminum ingot special of JIS H2111 (or ICS77.120.10) (99.995% or more)・ 1 kind (99.990% or more) ・ 2 kinds (99.95% or more), as a Cu raw material (metal), JIS H2121 electrolytic copper metal (99.96% or more), respectively. You can

  The raw material (metal) of Zn, which is the base element, is not particularly limited, and each grade specified in JIS H2107 (or ISO 725: 1981) can be used. Considering shot quality stability, JIS H2107 standard zinc ingot (99.97% or more), pure zinc ingot (99.995% or more), special zinc ingot (99.99% or more), etc. High purity zinc bullion may be used.

S02: Melting Step After the weighed metal is put into the crucible, the crucible is heated (for example, about 600 ° C.). The metal is melted by heating and becomes a molten metal having a composition of Zn-Al or Zn-Al-Cu.

S03: Molten Metal Transfer Step The molten metal is put into the molten metal holding container. The molten metal holding container is provided with a heating means, and can hold the molten metal during the production of shots of the zinc-based alloy so as not to be cooled more than necessary. The molten metal holding temperature at this time varies depending on the alloy composition and the production scale, but may be appropriately set in the range of 500 to 600 ° C.

  A nozzle for dropping molten metal is provided at the bottom of the molten metal holding container, and a cooling tank in which a cooling medium is charged is arranged below the nozzle. The cooling medium is a liquid, and may be water or oil.

S04: Granulation Step The molten metal in the molten metal holding container is dropped from the nozzle. By the time it reaches the cooling medium from the nozzle, it becomes spherical due to the influence of surface tension. The molten metal that reaches the cooling medium and comes into contact with it is rapidly cooled and solidified in a spherical shape.

  The temperature of the cooling medium rises due to the contact with the dropped molten metal, which causes the rapid cooling of the molten metal to be hindered. Therefore, the cooling medium holds the cooling medium at the set temperature. In the case of water, for example, the set cooling temperature may be usually 60 ° C. or lower, or 30 to 40 ° C.

S05: Classification step Zinc alloy particles are deposited on the bottom of the cooling medium. This is collected, dried with a drier, and then classified with a classifier to obtain a zinc-based alloy shot. It should be noted that the classification is performed so as to have a predetermined particle size in accordance with the intended use of the zinc-based alloy shot.

  Here, when the molten metal is dripped from the nozzle, the shape of the molten metal droplet is not a perfect sphere but is a distorted sphere or ellipse that is stretched in the falling direction. Therefore, the shape of the obtained granular material, that is, the particles of the shot, is a slightly distorted spherical shape, a spheroidal shape, or a cylindrical shape with rounded corners. When the length in the longitudinal direction of the shot obtained from such a projected view of the shot is a and the maximum diameter in the direction orthogonal to the longitudinal direction is b, a / b of 60% or more of the shots is 1.0 to It is preferably in the range of 1.3, and is also preferably in the range of 1.0 to 1.2. Since such a shot is close to a true sphere and has a small variation in shape, a more uniform polishing effect can be obtained. If the diameter of the granular material is 0.2 to 2.0 mm, the proportion of shots having a / b value of 1.0 to 1.3 or 1.0 to 1.2 is large, so the particle diameter is within this range. You may classify so that.

The content of Al with respect to the shot of the zinc-based alloy is 1.0 to 6.0%,
The content of Cu with respect to the shot of the zinc-based alloy is 0.0001 to 0.25 mass%,
The zinc-based alloy shot is a granular body having a diameter of 0.2 to 2.0 mm,
When the length in the longitudinal direction of the shot obtained from the projected view is a and the maximum diameter in the direction orthogonal to the longitudinal direction is b, a / b of 60% or more of the shots is in the range of 1.0 to 1.3. Within,
A zinc-based alloy shot having a Vickers hardness of the zinc-based alloy shot of 50 to 100 HV is particularly preferable.

The content of Al with respect to the shot of the zinc-based alloy is 1.3 to 5.8 mass%,
The content of Cu with respect to the zinc-based alloy shot is 0.0002 to 0.05%,
The zinc-based alloy shot is a granular body having a diameter of 0.2 to 2.0 mm,
When the length in the longitudinal direction of the shot obtained from the projection view is a and the maximum diameter in the direction orthogonal to the longitudinal direction is b, a / b of 60% or more of the shots is in the range of 1.0 to 1.2. Within,
The zinc-based alloy shot having a Vickers hardness of 70 to 90 HV is more particularly preferable.

  The method for producing the zinc-based alloy shot is not limited to the above method. An example of another manufacturing method will be described below with reference to FIG.

S11: Agglomerate manufacturing process An agglomerate having a composition of Zn-Al or Zn-Al-Cu is produced from a metal as a raw material. For example, a cylindrical mass called a billet may be produced by smelting a metal as a raw material.

S12: Wire manufacturing process In this embodiment, a wire is manufactured from a billet. By inserting the billet into a plurality of dies and pulling out the billet, the diameter of the billet is reduced by plastic deformation to manufacture a wire to a desired diameter. Since the billet of this embodiment contains Al, it has good slipperiness with a die. Therefore, when the wire is manufactured, it is possible to prevent the wire from being cut or microcracks being generated in the middle thereof.

  Further, the addition of Cu as a trace additive element improves the tensile strength of the zinc-based alloy. As a result, it is possible to further prevent the wire from being cut or microcracks being generated during the wire production.

  Since the billet made of a zinc-based alloy can pass through the die well by adding Al and Cu, the zinc-based alloy can give stress due to plastic deformation and friction with the die. As a result, the mechanical properties required for the shot (for example, toughness) can be improved. For example, the mechanical properties can be adjusted by changing the drawing speed of the billet and the diameter and number of dies.

  By reducing the diameter of the wire, the zinc-based alloy is given stress to improve its mechanical properties, but if it is made thinner than necessary, it will be damaged by this processing. Further, if the diameter is too large, sufficient stress is not applied, or when the blast processing is performed on a work having a relatively low hardness, the surface of the work is damaged. Based on the above, the diameter of the wire may be 0.4 mm to 2.0 mm.

S13: Cutting step The obtained wire is serially cut into a predetermined length to obtain a granular material. If the length of the granular material has a large difference from the diameter, the finished quality of the work after blasting varies. In consideration of this, the wire may be cut so that (1: 0.8) ≦ (wire diameter: wire length) ≦ (1: 1.3), and (1: 0.8) The wire may be cut so that ≦ (wire diameter: wire length) ≦ (1: 1.2).

S14: Rounding process Since the obtained granular material has a columnar shape, it has corners. If the work is damaged by the corners during blasting, the corners may be rounded by projecting the granular material toward a wall or the like in advance. Note that this step may be omitted depending on the physical properties of the work and the purpose of blasting.

The content of Al with respect to the shot of the zinc-based alloy is 1.0 to 6.0%,
The content of Cu with respect to the zinc-based alloy shot is 0.0001 to 0.25%,
The zinc-based alloy shot is a cylinder having a ratio of (1: 0.83) ≦ (diameter: length) ≦ (1: 1.25),
When the length in the longitudinal direction of the shot obtained from the projected view is a and the maximum diameter in the direction orthogonal to the longitudinal direction is b, a / b of 60% or more of the shots is in the range of 1.0 to 1.3. Within,
A zinc-based alloy shot having a Vickers hardness of the zinc-based alloy shot of 50 to 100 HV is particularly preferable.

The content of Al with respect to the shot of the zinc-based alloy is 1.3 to 5.8%,
The content of Cu in the zinc-based alloy shot is 0.0002 to 0.25%,
The zinc-based alloy shot is a cylinder having a ratio of (1: 0.83) ≦ (diameter: length) ≦ (1: 1.25),
When the length in the longitudinal direction of the shot obtained from the projection view is a and the maximum diameter in the direction orthogonal to the longitudinal direction is b, a / b of 60% or more of the shots is in the range of 1.0 to 1.2. Within,
A zinc-based alloy shot having a Vickers hardness of 70-90 HV is particularly preferable.

  Next, the result of evaluating the zinc-based alloy shot of one embodiment will be described.

Zinc-based alloy shots were taken from Al and Cu and Zn ingot weighed so as to have the ratios shown in Table 1 below by the above-described steps S01 to S05 (A type) or steps S11 to S14 (B type). Manufactured.
A type: A zinc-based alloy produced by steps S01 to S05 in the above production method and classified so that the average particle diameter is 0.8 mm and the a / b is 1.0 to 1.3.
B type: Zinc-based alloy shot manufactured by steps S11 to S14 and having a wire diameter of 0.8 mm.

  The following evaluation tests were performed on these zinc-based alloy shots.

  100 kg of zinc-based alloy shot was put into a shot blasting machine (DZB type: manufactured by Shinto Kogyo Co., Ltd.), and aluminum alloy die-cast parts (surface hardness: 100 HV) were blasted as a work to evaluate the performance. I did. The shot speed of shots of the zinc-based alloy was 53 m / s.

  The evaluation items were "consumable amount", "deburring ability" and "finished quality" as follows.

<Amount of consumption>
It is an evaluation corresponding to life or toughness (impact resistance). The amount of fine powder worn by shot blasting for 8 hours using a zinc-based alloy shot was evaluated as the "shot consumption amount" according to the following criteria.
◎: 0.06 kg / (h · HP) or less ○: 0.06 kg / (h · HP) to 0.08 kg / (h · HP)
Δ: 0.08 kg / (h · HP) to 0.10 kg / (h · HP)
×: 0.10 kg / (h · HP) or more

<Deburring ability>
It is an evaluation corresponding to the cleaning ability or blast ability. The blasting time required to completely remove burrs was measured and evaluated according to the following criteria. The burr was removed by visual evaluation.
A: Burrs are removed in a blasting time of 30 seconds.
◯: Burrs are removed in the blasting time of 60 seconds.
B: Burrs are removed in a blasting time of 90 seconds.
X: Burrs are not removed even after a blasting time of 90 seconds.

<Finishing quality>
The work surface after the blasting was observed and evaluated according to the following criteria (visual evaluation).
⊚: Shines silver white.
○: A little darkened.
Δ: Blackened.

The evaluation results are shown in Table 1. The "diameter-length ratio" in the table indicates "wire diameter: wire length" of the cut wire in a B type zinc-based alloy shot.

<Evaluation of consumption>
In any type of zinc-based alloy shots, Examples 1 to 10 in which the amount of Al added was in the range of 1.0 to 6.0% were evaluated as Δ or higher under any condition. Furthermore, even when Cu was added in a trace amount in the range of 0.0001 to 0.25%, the evaluation was Δ or higher under any of the conditions. Here, the Δ evaluation is a result that is inferior to the ○ evaluation but has no problem in practical use, and it is suggested that the evaluation can be more than the O evaluation by optimizing the projection conditions (projection speed, particle size, etc.). Therefore, in Examples 1 to 10, it can be seen that the evaluation of the amount of consumption is good.

  In the B type zinc-based alloy shots, when the composition was close to that of the type A zinc-based alloy shots, the evaluation of the consumption amount was the same or even better. It is considered that this is because the mechanical property of the zinc-based alloy shot was improved and the impact resistance was improved as a result, because the step of applying stress in the manufacturing process of the B-type zinc-based alloy shot was included. .

  Comparative Example 3 in which the added amount of Al was excessive and Comparative Example 4 in which the added amount of Cu was excessive were evaluated as x. In any case, it is considered that the impact resistance was deteriorated by excessively adding Al and Cu.

<Deburring ability>
In any of the types of zinc-based alloy shots, Examples 1 to 10 in which the amount of Al added is in the range of 1.0 to 6.0% show a tendency that the evaluation decreases as the amount of Al added increases. However, the evaluation was Δ or higher under any of the conditions. Furthermore, even when Cu was added in a trace amount in the range of 0.0001 to 0.25%, the evaluation was Δ or higher under any of the conditions. Here, the Δ evaluation is a result that is inferior to the ○ evaluation but has no problem in practical use, and it is suggested that the evaluation can be more than the O evaluation by optimizing the projection conditions (projection speed, particle size, etc.). Therefore, in Examples 1 to 10, it can be seen that the evaluation of the amount of consumption is good.

  In the B type zinc-based alloy shots, when the composition was close to that of the type A zinc-based alloy shots, the deburring ability was evaluated as equal or better. It is considered that this is because the mechanical properties of the zinc-based alloy shot are improved because the step of applying stress in the manufacturing process of the B-type zinc-based alloy shot is included.

  Comparative Example 1 in which Al was not added and Comparative Example 2 in which the addition amount was too small were evaluated as x. It is considered that this is because the Vickers hardness is low with respect to the work.

  Comparative Examples 5 and 6 in which the diameter-length ratio was too small or too large were evaluated as x. It is considered that since the shots of the zinc-based alloy shots collide with the work, the deburring ability is reduced.

<Finishing quality>
In any type of zinc-based alloy shots, Examples 3, 4, 7, 8, 9, and 10 in which Cu was added in a trace amount in the range of 0.0001 to 0.25% were evaluated as ⊚ under all conditions. Therefore, it was shown that the finish quality is improved by adding a trace amount of Cu.

  In addition, in Examples 1, 2, 5, and 6 in which Cu was not added, the evaluation was Δ or ◯, and when the results of Comparative Example 1 were taken into consideration, improvement of the finished quality was observed even by adding Al. It is considered that this is because the time required for the blasting to be completed was shortened due to the improved deburring ability, and the opportunity for the workpiece to be exposed to the shot flow of the zinc-based alloy shot was reduced.

  The zinc-based alloy shot of one embodiment is for removing burrs and burrs of non-ferrous metal parts such as aluminum die cast products and aluminum cast products, sand removal of cast products, seizure of molds and release agents, oxide film. It can be suitably used for shot blasting for the purpose of removing hot water and wrinkles, sealing treatment, and the like.

Claims (9)

Zinc-based alloy shot,
The zinc-based alloy shot comprises Al and the balance Zn and inevitable impurities,
The content of Al with respect to the zinc-based alloy shot is 1.0 to 6.0 mass%,
A zinc-based alloy shot, wherein the zinc-based alloy shot has a Vickers hardness of 50 to 100 HV.   The zinc-based alloy shot according to claim 1, wherein the zinc-based alloy shot has a Vickers hardness of 50 to 90 HV. Cu is further added as a trace additive element to the zinc-based alloy shot,
The zinc-based alloy shot according to claim 1, wherein the addition amount of the trace additive element is 0.0001 to 0.25 mass% with respect to the zinc-based alloy shot.   The zinc-based alloy shot is a granular material having a diameter of 0.2 to 2.0 mm, or has a ratio of (1: 0.8) ≦ (diameter: length) ≦ (1: 1.3). The zinc-based alloy shot according to any one of claims 1 to 3, which is a column having.   When the zinc-based alloy shot is a granular body, and the length in the longitudinal direction of the shot obtained from the projected view is a and the maximum diameter in the direction orthogonal to the longitudinal direction is b, a of 60% or more of the shots is a. The zinc-based alloy shot according to any one of claims 1 to 4, wherein / b is in the range of 1.0 to 1.3. A method for manufacturing the zinc-based alloy shot according to any one of claims 1 to 5,
A step of weighing Zn, Al that is a raw material metal, and Cu if necessary,
A step of heating the raw material metal to form a molten metal;
A step of transferring the molten metal to a molten metal holding container having a nozzle arranged at the bottom,
A step of dropping the molten metal into a liquid cooling medium through the nozzle;
A step of solidifying the molten metal in the cooling medium to obtain a granular body,
A step of classifying the granular material into a predetermined size,
Including,
In the classification step, the diameter of the solidified molten metal is classified to 0.2 to 2.0 mm, and the zinc-based alloy shot manufacturing method. A method for manufacturing the zinc-based alloy shot according to any one of claims 1 to 4,
A step of obtaining a lump having an alloy composition of Zn, Al that is a raw material metal, and optionally Cu,
Obtaining a wire having a predetermined diameter from the lump,
Cutting the wire into a predetermined length,
Including,
In the step of obtaining the wire, the method for producing the zinc-based alloy shot, which includes a step of rolling a lump and applying stress.   The zinc according to claim 7, wherein in the step of cutting the wire, the wire is cut such that (1: 0.8) ≦ (wire diameter: wire length) ≦ (1: 1.3). Method of manufacturing base alloy shot.   The method for producing a zinc-based alloy shot according to claim 7 or 8, wherein in the step of obtaining the wire, the lump is processed so that the diameter of the wire is 0.4 to 2.0 mm.

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