KR101237904B1 - Zinc-based alloy shots - Google Patents

Abstract

The present invention provides a zinc-based alloy shot which has no risk of dust explosion, high burr removal by shot blasting, abrasive cleaning capability and provision of compressive residual stress by shot peening, and low consumption of shot by shot. .
As an additive element, AEL: 0.5-6.5 mass%, Cu: 0.5-4.5 mass%, Mass composition ratio (Aｌ / Cu) of AEL and Cu, 1.0-13.0, and total amount (Aｌ + Cu): 1.5-10.5 mass %, Vickers hardness of 90-190HPa, three-component zinc-based alloy short and additive element, A: 0.5-6.5 mass%, Cu: 0.5-4.5 mass%, Mg: 0.01-0.2 mass%, The mass composition ratio (Cu) of Cu, 1.0-3.0, the total amount of addition (Ac + Cu): 1.5-8.0 mass%, and the four-component zinc-based alloy shot of Vickers hardness of 90-190HPa.

Description

Zinc-based alloy shot {ZINC-BASED ALLOY SHOTS}

The present invention removes burrs and fins of nonferrous metal parts such as, for example, aluminum die-cast products and aluminum casting products (hereinafter referred to as "deflashing"), And sand strips of castings, removal of burnt deposits of coatings or parting agents, or removal of oxides or scales or flow lines (hereinafter referred to as "polishing". Shot blasting for the purpose of "grinding and cleaning" or for shot machining used in shot peening for the purpose of improving the fatigue strength of welded parts of non-ferrous metal parts or non-ferrous metal parts. .

In this specification, Vickers hardness means the thing measured on condition of the test force 0.4093N and the holding time of test force: 10-15s in JIS Z 2244, but is displayed as "000HＶ0.05", , Abbreviated as "000HＶ".

In addition, "%" which shows an alloy composition means "mass%", unless it is particularly determined.

Conventionally, die-cast parts made of non-ferrous metals such as aluminum-based alloys, zinc-based alloys, or Mg-based alloys, which are used in automobile parts or the like, may be used to eliminate molded articles. As a surface treatment for the purpose of abrasive cleaning etc., shot blasting which projects a small ball called shot to a to-be-processed object at high speed is used a lot.

In recent years, as a surface treatment for the purpose of improving the fatigue strength of welded portions of non-ferrous metal parts and non-ferrous metal parts, shot peening for projecting shots to an object to be processed at high speed has been used, similarly to shot blasting.

As a material of the shot used for this shot blasting, the shot which consists of aluminum type alloy, stainless steel, and zinc type alloy has been used generally.

Due to the low specific gravity, aluminum-based alloy shots do not have sufficient abrasive cleaning ability, and the explosion sensitivity of the cloud of dust due to shot fracture occurring during shot blasting based on the material properties of aluminum It is high, and the lower explosion concentration is low. For this reason, extra work safety management is required.

The stainless steel shot includes Ni (Spirit No. 231) and Cr (Spirit No. 68), which are subject to the chemical emission movement notification system (PRTR, "Pollutant Release and Transfer Register" system). For this reason, it is in the direction of restriction | limiting of use from a viewpoint of work safety and environmental conservation.

Zinc-based alloy shots have a lower explosion sensitivity of dust clouds due to shot fracture and higher explosion lower concentrations than aluminum alloy shots and stainless steel shots. For this reason, in view of safety, it is most recently used as shot blasting and shot peening of non-ferrous metal die-cast products.

As prior art documents relating to zinc-based alloy shots, although there is no influence on the patentability of the present invention, Patent Documents 1 to 5 and the like exist.

Japanese Patent Laid-Open No. 11-320416 Japanese Patent Laid-Open No. 2001-162538 Japanese Patent Publication No. 2007-84869 Japanese Patent Laid-Open No. 9-70758 Japanese Patent Publication No. 2002-224962

In the surface treatment for the purpose of the blow blasting, the abrasive cleaning by the shot blasting, and the improvement of the fatigue life by the shot peening, etc., it is preferable to use the shot according to the surface hardness of the to-be-processed object in order to achieve these objectives.

For example, it is preferable to use the short vicinity of those hardness or more for aluminum die-casting products of Vickers hardness 90-110 HPa.

However, in zinc-based alloy shots having a hardness above these hardness, it is not very useful to have toughness. This is because the zinc-based alloy shot usually has a decrease in toughness in proportion to the increase in hardness.

On the other hand, in patent document 2, in order to improve shot durability as an addition element, the technique of adding Mn (addition amount: 0.3-5.0%) is proposed. However, Mn is also the object of the PRT system (Element No. 311), and there exists a problem like a stainless steel short.

And in the zinc-based alloy shot, the appearance of the technique which improves durability, without adding an element, such as Mn which becomes a target of the PRT system, was calculated | required from the standpoint of the recent environmental problem.

As a result of intensive studies to solve the problems of these zinc-based alloy shorts, the inventors of the present invention do not need to add a target element of the PRT system in the case where A and Cu are added to Zn and adjusted to a specific alloy composition. It was found that there was an alloy composition capable of producing a zinc-based alloy short having a Vickers hardness of 100 HPa or more and high toughness, and reached the present invention having the following constitution.

The present invention (first invention) is a zinc-based alloy short of three components containing AEL: 0.5 to 6.5% and Cu: 0.5 to 4.5% as an additional element, and the mass composition ratio of AEL and Cu is / Cu) = 1.0-13.0, the total amount added (Aｌ + Cu): 1.5-10.5%, Vickers hardness: 90-190HPa, It is characterized by the above-mentioned.

1, the composition range (gray part) of this invention in the state diagram of the three-component alloy composition of a zinc-based alloy shot is shown schematically.

In the zinc alloy shot of the present invention, Al is added as an alloying element (essential element) in order to improve the impact resistance, which is a mechanical property that greatly affects the consumption amount of the shot. AEL has the effect of increasing the impact resistance (toughness), mechanical strength and Vickers hardness of the zinc alloy. If the amount of Al is added (based on a total amount of 100%; the same as below), less than 0.5% thereof is difficult to obtain their action, and when it exceeds 6.5%, the impact resistance tends to be lowered. Although it depends also on the addition ratio of Cu which is another addition alloy, the addition amount of suitable A20 for increasing impact resistance is 3.0-6.0 mass%, Preferably it is about 3.0-5.0%.

In addition, Cu is used as an additional element to improve the Vickers hardness of the zinc-based alloy shot. Cu has the effect of increasing the mechanical strength and Vickers hardness of the zinc alloy, and it is difficult to obtain their effect when the amount of Cu added is less than 0.5%. However, when the addition amount of Cu exceeds 4.5%, or when the total amount of Al and Cu added exceeds 10.5%, the mechanical strength and the Vickers hardness are improved, but the impact resistance tends to decrease (toughness). In the case of the zinc-based alloy shot of the present invention having a Vickers hardness of 140 HPa, which is sufficiently higher than the Vickers hardness of 100 HPa of the aluminum die-cast product, the most suitable addition amount of Cu is about 1.0 to 3.0%.

In the zinc-based alloy shot, as described above, when the Vickers hardness of 90 HＶ is lower, the burr removing ability and the abrasive cleaning ability are not sufficient. However, when the zinc alloy shot exceeds 190 HV, the burr removal, abrasive cleaning or peening is performed. During the treatment, cracking and wear of the zinc-based alloy shot easily proceed, and the consumption amount of the shot increases, which is not practical. This is due to the low toughness of the zinc-based alloy short. Therefore, the Vickers hardness which has sufficient burr removal ability, the abrasive cleaning ability, and the pinning ability, and is easy to obtain the thing of the short consumption (high toughness): 90-190HPa, Preferably it is in the range of 130-154HV, The shot is appropriately selected according to the processing target (product) or the processing purpose.

In the present invention having the above-described structure, the content of elements (non-essential elements) other than the three components (non-essential elements) included in the zinc-based alloy shot is 0.5% or less, and Fe content: 0.3% It is preferable to set it as follows.

Examples of the non-essential element include PI, Fe, CD, Sn, Si, Ti, Mn, As, Si, Si, and S. When the sum total of these non-essential elements exceeds 0.5%, a zinc type alloy short will be soft and toughness will fall easily. In particular, Fe has an adverse effect on toughness, and when Fe content exceeds 0.3% in total in the zinc alloy shot, the short consumption increases and is not practical as a shot (see Comparative Example 1-6 and Comparative Example 2-3). .

In this invention of the said structure, it is preferable that each purity of A20 and Cu which are addition elements is 99.9% or more, and content of a non-essential element is 0.02% or less in total. In the production of zinc-based alloy shots, the reduction in toughness due to the entry of non-essential elements (impurities) and oxides of the non-essential elements contained in AA and Cu into grain boundaries can be made as small as possible (Example 1 -6, example 2-3).

Specifically, as a raw material (ingot) of the above-mentioned aluminum, one kind of aluminum foil specialty (99.90% or more) of ISH2102 or the refined aluminum metal specialty of IHS2111 (or ICS 77.120.10) (99.995% or more), 1 type (99.990% or more), 2 types (99.95% or more), and as the raw materials (Cu) of the Cu, an electric copper foil of ISH2121 (99.96% or more) may be mentioned, respectively. have.

On the other hand, as a raw material (now) of the base metal (vin), it does not specifically limit, The grade of the grade prescribed | regulated by JSH2107 (or ISO725: 1981) can be used. In view of the quality stability of the shot, it is possible to use high-purity ones such as ISH2107's ordinary zinc flakes (more than 99.97%), the lowest zinc flakes (more than 99.995%), and special zinc flakes (more than 99.99%). It is preferable.

Another invention (second invention) is a four-component zinc-based alloy short containing A-a: 0.5 to 6.5%, Cu: 0.5 to 4.5%, and Mg: 0.01 to 0.2% as an additional element, and the mass of A and Cu. It is a composition ratio (Ac / Cu): 1.0-13.0, the total amount of addition (Ac + Cu): 1.5-8.0%, Vickers hardness: 90-190 HPa, Preferably it is 140-150 HPa, It is characterized by the above-mentioned.

Similar to the first invention, in the second invention, the total amount of Al and Cu added (Ac + Cu) is 8.0% or less. In order to prevent the fall of the mechanical strength of a shot and a Vickers hardness, a trace amount of Mg is used as an addition element. Mg has a function of inhibiting recrystallization by depositing a Mg compound at the crystal interface of the zinc alloy, and also has an effect of improving mechanical strength and Vickers hardness. Mg: When it is less than 0.01%, it is hard to obtain recrystallization inhibitory effect, and when it exceeds 0.2%, there exists a possibility that it may inhibit the effect of the improvement of the resistance to impact by addition of AEL and Cu. And when the addition element composition from which the zinc-based alloy shot before and after Vickers hardness 140Hb is made into 3.0 by 5.0% and Cu: 1.0-3.0%, the addition amount of suitable Mg is 0.01-0.2%, Preferably it is 0.03-0.08 %to be. On the other hand, Vickers hardness of about 140 HPa is a shot hardness which is easy to acquire the effect of favorable shot blasting and shot peening with respect to a nonferrous metal product.

The reason for limitation of the numerical range of the addition amount of addition elements (Ag and Cu) other than Mg is the same as that of 1st invention.

In 2nd invention of the said structure, similarly to the case of 1st invention, content of non-essential elements other than the four components contained in a zinc-type alloy shot is made into 0.5% or less, and Fe content is made into 0.3% or less. It is preferable. The reason for the content limitation of these non-essential elements is the same as that of 1st invention.

In each invention which concerns on said 2nd invention, it is preferable that each purity of A20, Cu, and Mg which are the said additional elements is 99.9 mass% or more similarly to 1st invention. The reason for these purity limitations is the same as that of 1st invention.

On the other hand, specifically, the raw materials (now) of A, Cu, and Ben (N) are as described above, and as the raw material (now) of Mg, magnesium now of JSH150 (or Iso8287: 2000) is one species (99.90% or more). Can be mentioned.

Although the average particle diameter of the zinc-based alloy shot in the said 1st, 2nd invention differs also according to the intensity | strength of a to-be-processed object, and a processing objective, it is usually 0.1-3.0mm, Preferably it is 0.3-2mm can do.

When the average particle diameter is too small, it is difficult to obtain sufficient burr removing ability, abrasive cleaning ability or pinning effect (for example, imparting compressive residual stress). On the contrary, when the average particle diameter is too large, damages to the workpieces during burr removal, abrasive cleaning, or peening treatment, or surface roughness cannot be maintained.

When the average particle diameter of the shot is set to 0.1 to 3.0 mm, preferably 0.3 to 2 mm, a high abrasive cleaning effect can be exhibited and surface treatment such as burr removal of the workpiece can be performed within a short time. In addition, when the average particle diameter of shot is 0.3-0.6 mm, the beautiful surface with little surface roughness can be obtained.

The zinc-based alloy shot of the first and second inventions is a step of dripping a melted molten metal in a cooling medium such as water, and solidifying the melted metal molten in this cooling medium. ) Is produced by classifying a granular body which has undergone the step of forming and depositing c) and the step of drying the solidification and deposit.

Since the molten metal is dripped in a cooling medium by dropping the molten molten metal, the metal molten metal is rapidly cooled, resulting in a finer and more uniform structure than a general casting material. When used as shot blasting or shot peening, a zinc alloy shot is loaded with a very large external force. Therefore, by forming a fine and uniform structure, mechanical properties such as impact resistance and tensile strength are improved, and zinc alloy shot is shot. It can be used suitably as.

The zinc-based alloy shot of the present invention can provide a zinc-based alloy shot having high stability because the zinc-based alloy shot has a low explosion sensitivity and a high explosion lower limit concentration of dust clouds due to shot fracture.

Furthermore, since the zinc-based alloy shot of the present invention has a high hardness (Vickers hardness is 90 HPa or more), the blow-blasting or abrasive cleaning ability by shot blasting is high, and the shot blasting treatment can be performed in a short time, resulting in high productivity. In addition, because of the high toughness that conventional zinc-based alloy shots do not have, the consumption of zinc-based alloy shots is reduced, and the amount of dust generated due to shot fracture is also reduced.

Similarly, when used in shot peening, the zinc-based alloy shot of the present invention, which has high hardness and high toughness, can efficiently cause plastic deformation on the surface layer of an object to be treated to impart a compressive residual stress. In addition, as in the case of shot blasting, the amount of dust generated due to shot fracture is also reduced.

Moreover, the zinc-based alloy shot of the present invention has a relatively small decrease in the mechanical strength of the shot due to the recrystallization of the metal structure, and the Vickers hardness during use of the zinc-based alloy shot is stabilized. For this reason, as an effect, a variation is reduced in the finishing of the to-be-processed object after shot blasting and shot peening, and surface quality is also stabilized.

In addition, the zinc-based alloy shot of the present invention has a small amount of dust and does not contain Mn, which is the object of the PRT system, and is also preferable in view of environmental conservation and work safety.

1 is a three-component state diagram showing the alloy composition range of the present invention.
2 is a flowchart showing an example of a method for producing a zinc-based alloy shot of the present invention.

The case where the zinc-based alloy shot in the present invention is manufactured by using a method of manufacturing granules by dropping molten metal is described below (see FIG. 2).

First, the ingot 12 (base material) 12 of the base element and the addition elements (A, Cu and Mg) is weighed and placed in a crucible 14 so as to have a set alloy composition ratio.

Next, by heating the crucible 14 with a heating means (resistance heating) 15, the injected ingot (now) mixture is dissolved to obtain a molten metal (16). Although the melting heating temperature at this time changes with alloy composition and production scale, it sets normally suitably in the range of 550-700 degreeC (preferably 580-600 degreeC). In addition, melting | fusing point of each element is as follows.

Kn: 419.6 ° C, Cu: 1083.4 ° C, A: 660 ° C, Mg: 648 ° C

Next, the molten metal 16 is poured into the molten metal holding vessel 18. The molten metal holding container 18 is provided with the heating means (resistance heating) 20, and can hold | maintain so that the molten metal 16 may not be cooled more than necessary at the time of zinc type alloy shot manufacture. The molten metal holding temperature at this time varies depending on the alloy composition and the production scale, but is usually appropriately set within the range of 500 to 600 ° C (preferably 520 to 550 ° C).

The dripping nozzle 22 for dripping melt is provided in the bottom part of the molten metal holding container 18, The cooling medium 24, such as water, is put in the lower part of the said nozzle 22, and a cooling means (cooling tower ( cooling tower) 26 is provided with a cooling tank 28. The cooling medium 24 may be oil or the like.

The molten metal 16 in the molten metal holding vessel 18 is dropped from the dropping nozzle 22 to contact air at the time of passing through the air from the dropping nozzle 22 to the cooling medium 24, and moreover. As a result of cooling due to contact with the cooling medium 24, spherical shape is affected by the surface tension.

Here, when the molten metal 16 is dripped from the dripping nozzle 22, the shape of the droplet of the molten metal 16 is not a perfect sphere but is stretched in a fall direction, and becomes a distorted sphere or ellipse shape. For this reason, the granular body 30 obtained, ie, the short particle shape, becomes a somewhat distorted spherical shape, a rotating ellipse shape, or a rounded cylindrical shape. When the length in the longitudinal direction of the short obtained from the projected figure of such a shot is a and the maximum diameter in the direction orthogonal to the longitudinal direction is b, a / b of 60% or more short is 1.0 to 1.2. It is preferable to be in a range. Such shots are close to the true sphere and have a small variation in shape, so that a more uniform abrasive cleaning effect is obtained. On the other hand, the projection degree of a shot can be obtained by well-known means, such as microscope observation and image analysis by imaging.

On the other hand, in the cooling medium 24, the temperature of the dropping molten metal rises as it contacts, and it causes the quenching of the dripping molten metal. For this reason, the cooling means 26 maintains the cooling medium 24 at a set temperature. This set cooling temperature is made into 60 degrees C or less (preferably 30-40 degreeC) normally in water. When it exceeds 60 degreeC, the water which contacted dripping melt boils and an interface will become a vaporization state, and it will become difficult to exhibit a quenching action.

At the bottom of the cooling medium 24, a granular body 30 of zinc alloy is deposited. This is collected, dried in a dryer (rotary dryer) 32, and classified by a classifier (a shaking sieve) 34 to obtain a zinc-based alloy short. In addition, classification is performed so that it may become a predetermined particle diameter according to the purpose of use of a zinc type alloy shot.

In addition, the manufacturing method of a zinc type alloy shot is not limited to the said dropping assembling method. For example, the shape and the particle size of the zinc-based alloy shot for which a known method such as a gas atomization method, a centrifugal atomization method, and a water atomization method are respectively used. Can be appropriately selected according to.

Example

Hereinafter, the Example performed with the comparative example in order to confirm the effect of 1st, 2nd invention is demonstrated.

Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-6 are in the first invention, Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-3 are in the second invention, Respectively.

Each raw material of the alloying element used the following each ingot. The Fe content (permissible upper limit value) is added together with the purity (lower limit value) of each current JIS rule. On the other hand, Fe of "first class recycle material of copper wires" is an estimated value.

Total alloying element raw material: 200kg

Use Now (A) (Examples and Comparative Examples except Example 1-6 and 2-3)

Zn: 99.97% of ordinary zinc oxide (VISH2107), Fe: 0.01%,

AC: 99.00% aluminum (third class) (IESH2102), F: 0.80% 、

Cu: 99.87% copper waste (WIS2109), F: 0.01%,

Mg: Magnesium now 2 types (VISH2150) 99.8%, Fe: 0.05%,

Use now (B) (Examples 1-6 and 2-3)

Zn: 99.97% of ordinary zinc oxide (VISH2107), Fe: 0.01%,

AC: 99.90% of aluminum 1 type (JPSH2102), F: 0.07% 、

Cu: 99.96% of electric copper foils (IESH2121), Fe: 0.01%,

Mg: Magnesium, now 1 type (JISH2150) 99.90%, Fe: 0.01%,

Each alloy shot was manufactured as shown in Tables 1 and 2 in the method (drop assembly method) shown in FIG. 2 described above under the following conditions.

Melting temperature: about 600 ℃

Melt holding temperature: about 550 ℃

Cooling medium (water) holding temperature: 40 ℃

In addition, the sum of non-essential elements (impurity) and Fe content in each Example and a comparative example is calculated | required from each JIS display composition, and is shown in Table 1 (1st invention correspondence) -2 (2nd invention correspondence). Comparative Example 1-6 and Comparative Example 2-3 were Fe-added and adjusted to Fe content: 0.35%, respectively.

That is, the total amount of impurities is 0.014 to 0.092% of Examples 1-1 to 1-8 and Examples 2-1 to 2-3, and Comparative Examples 1-1 to 1-6 and Comparative Examples 2-1 to 2 -3 was 0.032-0.378.

Furthermore, as the conventional example 1, using 99.9% or more of each raw material now, the additive element composition "Ae: 0.01%, Mn: 1.9%", Vickers hardness: 88HPa, and the conventional example 2, the added element "Ae: 0.05%, Mn: 4.5%], Vickers hardness: 129 HV.

The Vickers hardness was measured about each shot produced in this way. These results are shown in later Tables 3 and 4.

About the zinc-based alloy shot of each Example and the comparative example prepared above, each evaluation test of (1) shot blasting and (2) shot peening was done.

(1) shot blasting evaluation test

50 kg of prepared zinc-based alloy shots (average particle diameter 1.0 mm, a / b of 1.2 or less shots of 70% or more) are projected by a "DV-type centrifugal projection apparatus (5HP)" (manufactured by Shinto Kogyo KK). The performance was evaluated by shot blasting to the die-casting parts (surface hardness: 100HPa) made from aluminum alloys at the speed of 45 m / s. In all, preliminary projection was performed for 8 hours, in which the recrystallization phenomenon of the metal structure of the injected zinc-based alloy shot was sufficiently stabilized, and the condition of the zinc-based alloy shot was so as to be in almost the same state as the actual shot blasting operation. Was used to adjust.

Evaluation items were performed as follows for the "short consumption" corresponding to toughness (impact resistance), the "burr removal ability" and the "polishing cleaning ability" corresponding to the blasting ability.

<Short consumption>

The amount which became fine powder and was damaged by shot blasting for 8 hours using a zinc-type alloy shot was evaluated by the following reference | standard as "shot consumption amount."

◎: 0.06 kg / (ｈHP) or less,

○: more than 0.06kg / (ｈHP) and less than 0.08kg / (ｈHP),

Δ: more than 0.08 kg / (ｈHP) and less than 0.10kg / (ｈHP),

×: more than 0.10kg / (ｈHP)

<Burr removal ability>

The following criteria evaluated.

(Double-circle): Burst can be removed in 30 second of shot blasting time, The result is extremely favorable,

(Circle): Burr can be removed in 60 second, and a result is favorable,

(Triangle | delta): Burr can be removed in 90 second, and the result is a little bad,

X: A burr cannot be removed even if it is shot blasted for 90 seconds, and it is bad.

<Abrasive cleaning ability>

The following criteria evaluated.

(Double-circle): The surface of the to-be-processed object after processing was shining in silver-white color,

○: similarly slightly turned dark (turned slightly dark),

(Triangle | delta): Similarly, it was turned dark.

Table 3 shows the results of these evaluations.

Next, the amount of Al content (0.5 to 6.5%) of the first invention will be described.

The zinc-based alloy shot of Comparative Example 1-1, which is less than 0.5%, has a small consumption of shots, but the Vickers hardness is low. Comprehensive evaluation became somewhat poor "△".

In the zinc-based alloy shots of Comparative Examples 1-2 and 1-3, which are excessive (more than 6.5%) of the Al content, the impact resistance (toughness) of the short is reduced due to the excessive addition of A1, and the consumption of the shot is somewhat higher. (Triangle | delta) ". Furthermore, in Comparative Examples 1-2 and 1-3, the specific gravity of the zinc-based alloy shot was reduced due to the excessive addition of A. As a result, the impact force of the zinc-based alloy shot on the workpiece was increased even though the Vickers hardness was improved. Lowers. For this reason, in the comparative example 1-2 and 1-3, the burr removal ability and the abrasive cleaning ability fell. The comprehensive evaluation of the zinc-based alloy short became somewhat poor "△".

Ag-added amount of 1st invention: The zinc-based alloy shot of Examples 1-1 to 1-3 which existed in the range of 0.5 to 6.5% had high impact resistance, and the short consumption amount became very small "◎". In particular, the zinc-based alloy shots of Examples 1-2 and 1-3 having a Vickers hardness of 130 HPa or more have high burr removal capability and abrasive cleaning ability, and the overall evaluation of the zinc-based alloy shots is extremely good. It became.

The amount of Cu addition (0.5 to 4.0%) of 1st invention is demonstrated.

Although the zinc-based alloy shot of Comparative Example 1-4 which becomes CUB addition amount is less than (less than 0.5%), the consumption amount of shot is very small "◎", but since Vickers hardness is low, abrasive cleaning ability is low and zinc-based alloy shot is short. Comprehensive evaluation became somewhat poor "△".

Excessive amount of Cu addition (greater than 4.5%) The zinc-based alloy shot of Comparative Example 1-5 was 190 HPa, which was extremely hard as a zinc alloy, and the burr removal ability and the abrasive cleaning ability were "◎" evaluation, but the Cu addition was excessively added. As a result, the toughness of the shot was lowered and the short consumption amount was increased to "Δ". This is attributable to the decrease in toughness of the zinc-based alloy short with increasing content of Cu.

Example 1-1 (Vickers hardness 92HV) and conventional example 1 (Vickers hardness HV88) regarding the zinc-based alloy shot of 1st invention, and Example 1-2 (Vickers hardness 130HV) and conventional example 2 (Vickers hardness HV129) Although the Vickers hardness is almost the same, respectively, the zinc-based alloy shot of the present invention has excellent burr removing ability and abrasive cleaning ability.

In general, zinc alloys tend to be recrystallized by aging, change in metal structure, and lower in hardness. In the evaluation test of the zinc-based alloy shot in the present shot blasting, the shot after the recrystallization is regarded as the actual shot blasting operation state, and preliminary projection for 8 hours is performed. Probably, the zinc-based alloy shots of the conventional examples 1 and 2 have a larger decrease rate in hardness than the zinc-based alloy shots of the present invention, which may result in poor burr removal capability and abrasive cleaning ability.

In addition, when the comparatively low purity material (Example 1-4) is used as the additive alloy, and the high purity material (Example 1-6), the case of Example 1-6 using the high purity material Although this Vickers hardness slightly decreased, the short consumption was small, and better results were obtained.

When the amount of Fe contained in the zinc-based alloy shot is small (Example 1-4) and in many cases (Comparative Example 1-6), Comparative Example 1-6 in which the Fe content is excessive is Vickers. While the hardness was lowered, both the short consumption, the burr removal ability, and the abrasive cleaning ability were reduced.

(2) Short peening evaluation examination

The prepared zinc alloy shot (average particle diameter 1.0 mm) was used by Shinto Kogyo Co., Ltd., DX centrifugal projection apparatus at a projection speed of 60 m / s until the coverage reached 300%. Shot peening at (workpiece of a continuous cast).

In any of the evaluation samples, the pre-projection of the zinc-based alloy shot was performed so that the recrystallization phenomenon of the metal structure of the injected zinc-based alloy shot was sufficiently stabilized for 8 hours to be in substantially the same state as the actual shot peening operation. After adjusting the condition, short peening was performed. Table 4 shows the Vickers hardness of the zinc-based alloy shot after preliminary projection.

In the shot peening test, the solution was subjected to solution heat treatment for 8 hours at 520 ° C for 8 hours, followed by water cooling and aging treatment at 160 ° C for 6 hours after standing for 12 hours. A plate-like shape test piece having a thickness of 5 mm, a width of 15 mm, and a length of 17 mm in parallel portions was used.

Shot peening evaluation was performed about each following item.

The evaluation items were performed as follows for the "improved rate of compressive residual stress" and "toughness (impact resistance)" corresponding to the pinning effect.

Compression residual stress rate of change

The residual stress of the depth of 0.15 mm was measured from the surface of the center part of the to-be-processed surface of the test piece, and it evaluated on the following reference | standard by the change rate with respect to the residual stress-100 Mpa of a shot peening untreated article.

◎: 250% or more,

○: 200% or more but less than 250%,

Δ: less than 200%.

<Short consumption>

The amount which became fine powder and was damaged by shot peening for 8 hours using a zinc-type alloy shot was evaluated by the following reference | standard as "short consumption amount."

◎: 0.06 kg / (ｈ ・ P) or less,

○: more than 0.06kg / (ｈ ・ P) 0.08kg / (ｈ ・ P) or less,

Δ: more than 0.08 kg / (ｈ P) and 0.10 kg / (ｈ P) or less,

X: More than 0.10 kg / (ｈ ・ P).

"Comprehensive determination" of the above-mentioned "rate of improvement of compressive residual stress" "consumption amount of a short" was evaluated, and the extremely good thing (circle), the good thing (circle), the somewhat poor thing (triangle | delta), and the poor thing were evaluated as x. The evaluation results are shown in Table 4.

In the zinc-based alloy shots of Examples 1-2 to 1-5 which are the zinc-based alloy shots of the first invention, the Vickers hardness decreased by about 27 to 45% by preliminary projection, and the Vickers hardness became 90 to 97 HPa. In the case where the total amount of Al and Cu was less than 7.5%, it was found that the metal structure recrystallized by repeated use of zinc-based alloy shots, thereby decreasing the mechanical strength and Vickers hardness of the zinc-based alloy shots. In other words, when the total of Al and Cu is less than 7.5%, the shot for shot peening is not necessarily optimal.

Therefore, the zinc-based alloy shots of Examples 1-2 to 1-5 have a lower hardness of the zinc-based alloy shot than the Vickers hardness of 104 HPa of the workpiece, and cannot sufficiently cause plastic deformation in the surface layer of the workpiece. The improvement rate of the compressive residual stress "was evaluated as" Δ "in which the pinning effect was less than 200%. The comprehensive evaluation of the zinc-based alloy shorts of Examples 1-2 to 1-5 became somewhat poor "Δ".

The zinc-based alloy shot of the first invention, wherein the zinc-based alloy shots of Examples 1-7 and 1-8, in which the total of A and Cu are more than 7.5%, decreases the Vickers hardness by about 29 to 32% by preliminary projection. Although the Vickers hardness before preprojection was 180-183 HPa, it was high hardness, and the Vickers hardness after preprojection was 122-130 HPa. As a result of securing the Vickers hardness higher than the Vickers hardness of 104 HPa of the workpiece, the zinc-based alloy shots of Examples 1-6 · 1-7 can sufficiently cause plastic deformation in the surface layer of the workpiece. It became evaluation of "(◎)" that extremely pinning effect that a "rate" is 250% or more. The consumption of a shot was a small evaluation of "(circle)", and the comprehensive evaluation of the zinc-based alloy shots of Examples 1-7 and 1-8 became a good one "(circle)".

The comparative example 2-1 which concerns on 2nd invention is 0.001% whose Mg addition amount is under (Mg: less than 0.01%). Although Mg was added, the effect which suppresses recrystallization reaction was not acquired, and the Vickers hardness after preprojection fell to 92 HPa (36% fall).

For this reason, in Comparative Example 2-1, the hardness of the zinc-based alloy shot was lower than that of Vickers hardness of 104 HPa of the workpiece. As a result of the evaluation of "Δ" with less pinning effect, the "improved compressive residual stress" was less than 200%. It became. The comprehensive evaluation of this zinc-based alloy shot became somewhat poor "△".

The zinc-based alloy shot of Comparative Example 2-2 is 0.3% having an excessive amount of Mg added (greater than 0.2%). As a result of precipitation of the Mg compound at the crystal interface of the zinc alloy by the addition of Mg, the decrease in Vickers hardness after preprojection was suppressed to 3%, and recrystallization was prevented. It became evaluation of "." The comprehensive evaluation of this zinc-based alloy shot became a poor thing "x".

In the zinc-based alloy shots of Examples 2-1 to 2-3, in which the total amount of AEL and Cu of the present invention is 7.5% or less and Mg is in the range of 0.01 to 0.2%, the recrystallization of the metal structure by repeated use It was suppressed and the decrease of Vickers hardness after preprojection was only about 6-12%. In addition, the absolute value of the Vickers hardness after preliminary projection is 123 to 141 HPa, and a hardness sufficiently higher than the Vickers hardness of 104 HPa of the workpiece is secured.

Accordingly, Examples 2-1 to 2-3 can sufficiently cause plastic deformation in the surface layer of the workpiece, and the evaluation results of "◎", which is extremely high in the pinning effect, in which the "improved compressive residual stress" is 250% or more. . In addition, since the fall of the impact resistance by Mg is in the addition range which can be suppressed, the "short consumption" is very small "(circle)" (Example 2-1, 2-3), and a small number of "(circle)" (Example 2-2). It was evaluated. The comprehensive evaluation of this zinc-based alloy shot became extremely good (Example 2-3), and good thing (Example 2-1 and 2-2).

As is clear from the description of the above embodiments, the zinc-based alloy shots of the examples according to the first invention and the second invention are made to achieve both high hardness (100 HPa or more) and high toughness that were difficult to obtain in the conventional zinc-based alloy shots. I could confirm that.

In the actual work production, the ability to suppress or grind by shot blasting and the ability to apply stress to shot peening are greatly improved, and the cost down by reducing the consumption of shot and the work environment by reducing dust generation amount The improvement effect is also compatible. Moreover, it does not include Mn etc. which become a target of the PRTR system.

In addition, when a relatively low purity material (Example 2-1) is used as the alloying element additive (Example 2-1) and a high purity material (Example 2-3), when using a high purity material, Vickers hardness, Vickers after preprojection The hardness and residual compressive stress were slightly higher, and the short consumption was smaller, and better results were obtained.

In addition, when the amount of Fe contained in the zinc-based alloy shot is small (Example 2-1) and in many cases (Comparative Example 2-3), Comparative Example 2-3 having a high Fe content is Vickers hardness. After the preliminary projection, both the Vickers hardness and the residual compressive stress were lowered, and the overall evaluation was "x".

In Comparative Example 2-3, in which the amount of Mg added exceeded (0.2%), the residual compressive stress was slightly larger than that of Example 2-2, but the short consumption was reduced. This is considered to be due to the reduced toughness of the zinc-based alloy shot due to the excessive addition of Mg.

12... Ingot (now raw material)
14 ... Crucible
16 ... Molten metal
18 ... Molten Oil Oil Container
22... Dropping nozzle
24 ... Cooling medium (water)
32 ... Dryer
34... Classifier

Claims (26)

As a three-component zinc-based alloy shot containing AEL: 0.75 to 6.5% by mass and Cu: 0.5 to 4.5% by mass as an additive element, the mass composition ratios of AEL and Cu are 1.0 / 13.0 and the total amount of addition ( A ++ Cu): Zinc-based alloy shot, characterized in that 1.5 to 10.5% by mass, and Vickers hardness is 90 to 190HV 0.05. The method of claim 1,
The total content of elements (non-essential elements) other than the three components included in the zinc-based alloy shot is: 0.5% by mass or less, and Fe content: 0.3% by mass or less. The method according to claim 1 or 2,
The purity of each of the addition elements AEL and Cu is 99.9% by mass or more, and the content of the non-essential elements is 0.02% by mass or less in total. The method of claim 1,
Zinc-based alloy shot, characterized in that used for the surface treatment of non-ferrous metal products consisting of aluminum alloy, zinc alloy or magnesium alloy. 5. The method of claim 4,
A zinc-based alloy shot, wherein the zinc-based alloy shot is a three-component zinc-based alloy shot containing AEL: 3.0 to 6.0 mass% and Cu: 1.0 to 3.0 mass%. The method of claim 1,
A zinc-based alloy shot, which is used for surface treatment of deburring of a nonferrous metal product made of an aluminum-based alloy, a zinc-based alloy, or a magnesium-based alloy, and has a Vickers hardness of 130 to 154 HＶ0.05. As an additive element, a four-component zinc-based alloy shot containing AEL: 0.75 to 6.5% by mass, Cu: 0.5 to 4.0% by mass, and Mg: 0.01 to 0.2% by mass, wherein the mass composition ratios of AEL and Cu are as follows. : 1.0-13.0, total amount of addition (Aｌ + Cu): 1.5-8.0 mass%, and the Vickers hardness is 90-190HPa 0.05 The zinc-based alloy shot characterized by the above-mentioned. The method of claim 7, wherein
The content of non-essential elements other than the said four components contained in the said zinc-based alloy shot is 0.5 mass% or less, and the content of Fe is 0.3 mass% or less, The zinc-based alloy shot characterized by the above-mentioned. 9. The method according to claim 7 or 8,
The purity of each of the above-described additive elements AEL, Cu and Mg is 99.9% by mass or more, and the content of the non-essential elements is 0.02% by mass or less in total. The method of claim 7, wherein
Zinc-based alloy shot, characterized in that used for the surface treatment of non-ferrous metal products consisting of aluminum alloy, zinc alloy or magnesium alloy. The method of claim 10,
A zinc-based alloy shot, characterized in that it is a four-component zinc-based alloy shot containing Al: 3.0 to 5.0 mass%, Cu: 1.0 to 3.0 mass%, Mg: 0.01 to 0.2 mass%. The method of claim 7, wherein
A zinc-based alloy shot, which is used for surface treatment of deburring of a nonferrous metal product made of an aluminum-based alloy, a zinc-based alloy, or a magnesium-based alloy, and has a Vickers hardness of 140 to 150HＶ 0.05. The method of claim 7, wherein
A zinc-based alloy shot, which is used for the surface treatment of pinning of a nonferrous metal product made of an aluminum-based alloy, a zinc-based alloy, or a magnesium-based alloy, and has a Vickers hardness of 140 to 150 HＶ 0.05. The method according to any one of claims 1, 2, 4 to 8, and 10 to 13,
Zinc-based alloy shot, characterized in that the average particle diameter of the particles is 0.1 ~ 3mm. The method for producing a zinc-based alloy shot according to any one of claims 1, 2, 4 to 8, and 10 to 13, wherein the molten metal melt is placed in a cooling medium such as water. Preparation of zinc-based alloy shot characterized by classifying and manufacturing the granular body which passed through the process of dripping, the process of solidifying and depositing, and the process of drying the solidification and deposit collected by the said process of solidifying and depositing. Way. A method for producing a zinc-based alloy shot according to claim 14, wherein the molten metal melt is dropped into a cooling medium such as water, the solidifying and depositing step in the cooling medium, and the solidification recovered in the step of solidifying and depositing. A method for producing a zinc-based alloy shot, characterized by classifying and producing a granular body which has undergone a step of drying the deposit. As a zinc-based alloy shot manufactured by the manufacturing method of Claim 15, when the length in the longitudinal direction of the particle | grains of a zinc-based alloy shot is a and the largest diameter in the direction orthogonal to the said longitudinal direction is 60, 60 A / b of% or more shots exists in the range of 1.0-1.2, The zinc-based alloy shot. The zinc-based alloy shot manufactured by the manufacturing method of Claim 15 whose average particle diameter of a particle | grain is 0.3-2.0 mm, The zinc-based alloy shot characterized by the above-mentioned. 18. The method of claim 17,
The average particle diameter of a particle | grain is 0.3-2.0 mm, The zinc type alloy shot characterized by the above-mentioned. 19. The method of claim 18,
The average particle diameter of a particle | grain is 0.3-0.6 mm, The zinc type alloy shot characterized by the above-mentioned. 20. The method of claim 19,
The average particle diameter of a particle | grain is 0.3-0.6 mm, The zinc type alloy shot characterized by the above-mentioned. delete delete delete delete delete

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