JPH08229657A - Member for casting and its production - Google Patents

Abstract

PURPOSE: To provide a member for casting having erosion resistance, deposition resistance, thermal crack resistance, further excellent mechanical property, wear resistance, also good heat retaining property, light weight and its production method. CONSTITUTION: All surface or part of a base material is coated with the plated film containing >=30wt.% in total one or more kind elements selected among the group consisting of Ni, Co, Cr, Fe and >=1wt.% B. The plated film preferably contains >=3wt.% carbide particle or oxide particle, further, the base material is preferably made of titanium or titanium alloy. The plating film is formed by wet plating, electroplating is preferably used for wet plating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, such as a plunger sleeve, a plunger tip, a casting pin or a die body used for aluminum die casting, comes into contact with a high temperature molten metal at the time of casting and undergoes a severe thermal cycle. TECHNICAL FIELD The present invention relates to a casting member for a casting mold used in a state in which the above-mentioned action and a manufacturing method thereof.

[0002]

2. Description of the Related Art Since a casting member comes into contact with a molten metal having a high temperature at the time of casting, it is subjected to a severe heat cycle and is apt to cause melting loss, welding or heat crack. For this reason, conventionally, a casting member used in an aluminum die casting mold or the like has excellent strength and toughness in a high temperature environment according to JIS.
-Hot work tool steel represented by SKD61 is widely used.

Usually, when hot work tool steel is used as a member for die casting, in order to secure the fatigue strength and the heat crack resistance, in order to improve the tensile strength, the yield strength, the toughness and the ductility, the tempering and tempering are performed. Quality is done.

However, when the hot work tool steel is subjected to the heat treatment as described above, the mechanical properties can be improved, but the reaction with the molten metal causes melting loss, welding or abrasion, etc. Properties, heat cycle resistance and high temperature wear resistance deteriorate.

Therefore, after the above heat treatment, a nitriding treatment by a salt bath method (tuftride method), a gas method or a plasma method, a carburizing treatment by a TD process, PVD (physical vapor deposition) or CVD for coating a hard film is performed.
(Chemical vapor deposition) or application of various thermal spraying treatments including thermal spraying of self-fluxing alloys is being studied.

[0006]

However, the nitriding treatment, carburizing treatment or heat treatment such as PVD or CVD is
Although it is possible to improve wear resistance, it is not sufficient to improve the melting loss resistance and heat cycle resistance that are most required for casting members such as die casting dies.

Further, since the nitriding treatment, carburizing, TD process, thermal spraying and the like are performed by high temperature treatment, the base material may be deformed or thermally deteriorated.

Further, when the temperature of the molten metal is lowered, the flowability of the molten metal is deteriorated and the quality of the die-cast product is deteriorated. Therefore, especially for a mold part such as a plunger sleeve or a sprue which comes into contact with the molten metal. Even if the molten metal comes into contact with the molten metal, it is necessary to suppress the temperature decrease as much as possible. In order to prevent the temperature drop of the molten metal, titanium alloys with lower thermal conductivity than SKD steel are used or are being considered for mold parts such as plunger sleeves and sprues, but similar to SKD steel. Will cause melting loss or welding.

The present invention has been made in view of the above problems, and has not only melting resistance, welding resistance and heat crack resistance, but also excellent mechanical properties and wear resistance, and good results. An object of the present invention is to provide a casting member having excellent heat retaining property and light weight, and a manufacturing method thereof.

[0010]

A casting member according to the present invention is formed on a substrate and the entire surface or a part of the surface of the substrate,
1 selected from the group consisting of Ni, Co, Cr and Fe
More than one element: 30% by weight or more in total, B: 1% by weight
And a plated film of an alloy containing the above. The plating film preferably contains carbide particles in an amount of 3% by weight or more, and the plating film preferably contains oxide particles in an amount of 3% by weight or more. Furthermore, it is preferable that the plating film has a higher content of B, carbide or oxide on the surface side. On the other hand, the base material is preferably made of an austenite alloy or titanium or a titanium alloy.

In the method for producing a casting member according to the present invention, one or more elements selected from the group consisting of Ni, Co, Cr and Fe on the surface of the base material: 30% by weight or more in total,
The method is characterized by including a step of forming an alloy film containing B: 1% by weight by wet plating. Further, the wet plating is preferably electroplating.

[0012]

The present inventors have developed a casting member which has not only melting resistance and heat crack resistance but also excellent mechanical properties and wear resistance, and also has good heat retention and light weight. Therefore, various experimental studies were conducted. As a result, they have found that an extremely excellent casting member can be obtained by forming a plating film having a predetermined composition on the surface of the base material. Hereinafter, the plating method, the component composition of the plating film, and the reasons for limiting the base material will be described.

Plating method: In the wet-plated casting member, the casting member is subjected to a surface treatment or the like in order to improve the corrosion resistance, welding resistance and heat crack resistance. This may be, for example, nitriding, carburizing, TD process or thermal spraying. However, since these treatments are performed in a high temperature environment, thermal deformation or thermal alteration of the substrate may occur. Further, since some casting members are large-sized or have complicated shapes, it is necessary that such casting members can be easily treated. Further, it is necessary that the inner surface of a sleeve, which is a casting mold component, be easily treated. Considering the above,
In the present invention, wet plating is used for treating the casting member. Since wet plating can be performed at a low temperature of less than 100 ° C., the above-described base material is not thermally deformed, and even if it is large or has a complicated shape, a coating film can be easily formed. Can be formed.

Further, the wet plating is roughly classified into electroless plating and electroplating. For those having complicated shapes, electroless plating is effective for forming a uniform plating film.

On the other hand, electroplating is superior to electroless plating in the following points. That is, in electroless plating, the maximum film thickness formed is about 50 to 100 μm,
Considering the erosion rate of the plating film, the film thickness in the above range may not be sufficient for some cast parts. However, in electroplating, a film having a film thickness of more than 100 μm can be formed, so that a required film thickness can be formed according to the use site of the casting member.

In electroplating, a wide range of metals or alloys can be used for forming the plating film, and plating films having various compositions can be formed according to the use site of the casting member.

Further, in electroplating, the film formation rate may be 3 to 5 times faster than in electroless plating depending on the composition of the alloy, and since the life of the plating solution is long, the productivity is excellent and the plating rate is high. The cost required for can be reduced.

As described above, in wet plating in the coating film forming process of casting members, electroplating has more advantages than electroless plating, but both are taken into consideration in consideration of the use site of casting members. It is preferable to properly use plating.

Next, the reasons for limiting the component composition of the plating film will be described.

Ni, Co, Cr and Fe: 1 or more and
30% by weight or more in total Ni, Co, Cr and Fe are all elements that improve the toughness, and when the toughness of the plating film is improved, the heat crack resistance of the casting member is improved accordingly. If the addition amount of these elements in the plated film is less than 30% by weight, the toughness of the plated film cannot be improved. Therefore, one or more kinds of Ni, Co, Cr and Fe are contained in the plating film, and the total amount thereof is 30% by weight or more.

B: 1% by weight or more B is an element that improves the resistance to molten metal. Since the casting member comes into contact with the molten metal, excellent molten metal resistance is particularly required for the plating film formed on the surface of the casting member. If the added amount of B in the plated film is less than 1% by weight, the molten metal resistance of the plated film cannot be improved. Therefore, the content of B is set to 1% by weight or more. In addition,
In order for the plated film to have a remarkable resistance to molten metal, the amount of B added is preferably 3% by weight or more, and in order to further improve the resistance to molten metal, the added amount of B should be 5% by weight. % Or more is preferable.

To add B to the plating film, N
It can be added by forming a boride powder of i, Co, Cr or Fe, or by making a solid solution of boron atoms in the matrix. In addition, N such as TiB ₂ or ZrB ₂
Borides other than i, Co, Cr or Fe can be added to the plating film.

Carbide particles: When the surface of the base material is coated with a plating film containing 3% by weight or more of carbide particles, the member has improved wear resistance and melt damage resistance.
This is because the carbide has the property of improving the hardness of the plating film, and Ni, Co, which are contained as components of the plating film,
This is because the coexistence state with Cr and Fe is stable, and the wettability to molten metal is extremely large. If the addition amount of the carbide particles is less than 3% by weight, the member cannot have wear resistance and melt damage resistance. Therefore, the content of the carbide particles is set to 3% by weight or more.

The types of carbides are WC and Cr.
₃ C ₂ , WTiC ₂ , ZrC, SiC or the like is preferable,
It is not particularly limited to these carbides. Also,
In order for the member to have remarkable wear resistance and the like, the addition amount of the carbide particles is preferably 6% by weight or more, and in order to further improve the wear resistance and the like, the addition amount of the carbide particles is 10% or more. It is preferable that the content is at least wt%.

Oxide particles: If 3% by weight or more of oxide particles are added to the plating film, the wear resistance and the melt damage resistance of the member can be improved, like the above-mentioned carbide particles. This is because the oxide has the property of improving the hardness of the plated film and has high wettability with respect to the molten metal.

When oxide particles are added to the plating film in addition to the above-mentioned carbide particles, the member has extremely excellent wear resistance and the like as compared with the case where only carbide particles are added. However, if the amount of oxide particles added is less than 3% by weight, the member cannot have such characteristics. Therefore, the content of oxide particles is 3% by weight or more.

The types of oxides are SiO ₂ and Mg.
O, CaO, ZrO ₂ , Al ₂ O ₃ , Y ₂ O _3, TiO _{2 and the} like are preferable, but not limited to these oxides. Further, in order for the member to have remarkable wear resistance and the like, the amount of oxide particles added is preferably 6% by weight or more.

When the base material is coated with a plating film having a higher content ratio of B, boride, carbide or oxide toward the surface layer side of the B, carbide and oxide concentration gradient plating film, the surface of the member The hardness is improved, and the corrosion resistance to molten metal is improved. Further, the concentration of B or the compound decreases at the interface of the plating film with the base material,
Since the metal component is increased, the adhesion between the base material and the plating film is improved. Therefore, by forming the plating film having such a concentration gradient, a casting member having extremely excellent characteristics can be obtained.

Substrate: Austenitic alloy, titanium or titanium
If the heat retention of the tan alloy casting member is low, the temperature of the molten metal is rapidly lowered, so that the flowability of the molten metal deteriorates and the quality of the cast product deteriorates. Therefore, when an austenitic alloy is used as the base material, its thermal conductivity is 1/2 that of SKD steel.
Since it is small as follows, it is possible to obtain a casting member having extremely good heat retention.

As the austenitic alloy, an aging precipitation type alloy, for example, A286 alloy (C: 0.05% by weight, Cr: 15% by weight, Ni: 26% by weight, Mo: 1.
2% by weight, Ti: 2% by weight, Al: 0.2% by weight, V:
It is preferred to use 0.3% by weight, Fe: balance. In such an alloy, since the strength of the member is improved by age hardening, the reliability in strength can be further improved.

Further, as with the A286 alloy, when C, P, Ti, Al, Nb, or V is added to the austenite alloy as an age hardening element, carbides due to aging,
Since a metal compound such as a nitride or a phosphide or a metal such as Ti or Al is deposited to improve the strength of the member, it is possible to obtain a casting member having excellent durability.

Incidentally, such age hardening is performed by the melting temperature of the aluminum alloy (melting point of aluminum: 660.2).
(° C.) Or a temperature slightly higher than 700 to 750 ° C., it progresses effectively and a precipitate is stably present. Therefore, when the age-hardened member is used as an aluminum casting mold or the like, the temperature of the molten metal is appropriately maintained, and the strength of the age-hardened austenitic alloy base material is improved. Thereby, the durability of the member is extremely improved.

Next, the case where titanium or a titanium alloy is used as the base material of the casting member will be described. Titanium or a titanium alloy has a small thermal conductivity like the above-mentioned austenite alloy. Therefore, when titanium or a titanium alloy is used as a base material, a casting member having extremely good heat retention can be obtained.

Further, since titanium or titanium alloy has extremely high strength characteristics not found in other materials, it is possible to manufacture a member that can be sufficiently used even if the member is thin. Therefore, when titanium or a titanium alloy is used as a casting member, the weight of the member can be reduced.

[0035]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples that depart from the claims of the present invention.

As the test materials in this example, SKD61 steel which is a hot work tool steel which is usually used, SUS304 steel which is an austenitic alloy steel, A286 alloy steel which is an austenitic alloy steel containing an age hardening element and titanium. Alloy was used.

The A286 alloy steel contains C: 0.05% by weight, Si: 0.50% by weight, Mn: 1.35% by weight,
Cr: 15% by weight, Ni: 26% by weight, Mo: 1.24
%, Ti: 2.1% by weight, Al: 0.26% by weight and V: 0.32% by weight with the balance being Fe. The titanium alloy is a Ti-based alloy containing 6% by weight of Al and 4% by weight of V. The material history of heat treatment and surface treatment of these test materials is as shown in Table 1 below.

[0038]

[Table 1]

Using the test materials of Examples No. 1 to 14 and Comparative Examples No. 1 to 4 shown in Table 1 above, tests were carried out for mechanical properties, wear resistance, melt damage resistance and heat crack resistance.

In the test of mechanical properties, a sample after the final treatment was cut out and subjected to hardness measurement and U-notch Charpy impact test.

In the wear resistance test, a pin-on-disc type sliding wear test was conducted. In this case, a wear test was conducted under the conditions shown in Table 2 below, using a disc that was subjected to the same treatment as the surface of each test material, and a pin of aluminum alloy (6021).

[0042]

[Table 2]

In the erosion resistance test, a temperature of 750 ° C.
After C8C aluminum was melted and the test material was immersed in it for 3 hours, the cross section was observed.

In the heat crack resistance test, a 1000-cycle heat cycle test was conducted by alternately moving the test material to the environment in water and in a furnace at a temperature of 650 ° C. under atmospheric pressure. The number of cracks generated per unit area on the cross section or the surface of the test material after the test was observed.

By the above-mentioned tests, the test results are compared by four-level relative evaluation for each test, and excellent, good, good, and bad evaluations are performed in the order of excellent evaluation. The results are evaluated as good or bad in the order of excellence according to the two-stage evaluation for the heat retention property and the lightness, based on “○”, “△” and “×”. Show. The thermal strain is shown by relative evaluation of the thermal strain generated during the surface treatment.

[0046]

[Table 3]

As shown in Tables 1 and 3 above, SKD steel and Ti alloys conventionally used as casting members are subjected to tempering heat treatment such as quenching, nitriding treatment, self-fluxing spraying and electroless plating treatment. All of Comparative Examples Nos. 1 to 4 performed are inferior to Examples Nos. 1 to 14 in total.

That is, Comparative Example No. 1 is excellent in mechanical properties because it has been subjected to quenching and tempering, but it is extremely inferior because other properties such as abrasion resistance are not improved.

Further, since the comparative example No. 2 is subjected to the same treatment as the comparative example No. 1 and then subjected to the surface treatment by nitriding, the abrasion resistance is slightly improved as compared with the comparative example No. 1, but it is still not sufficient. On the contrary, nitriding adversely deteriorated the mechanical properties as compared with Comparative Example No. 1. In addition, the melting resistance and heat crack resistance were not improved at all.

Further, in Comparative Example No. 3, the titanium alloy was subjected to self-fluxing spraying and then remelted at a temperature of 1100 ° C. Since this comparative example uses a titanium alloy, it is superior in heat retention and lightness to the SKD61 steel, but the thermal strain due to thermal spraying is extremely large, so the mechanical properties are higher than those of the comparative examples No. 1 and 2. Has deteriorated. Further, other characteristics such as abrasion resistance were not improved at all as compared with Comparative Example No2.

Furthermore, Comparative Example No. 4 is excellent in mechanical properties because SKD61 steel is subjected to electroless plating, but the content of B in the plating film is lower than the lower limit value of 1% by weight in the limited range of the present invention. Since the amount is small, the other properties such as abrasion resistance are not improved and are extremely inferior.

On the other hand, in Examples Nos. 1 to 14, the conditions in the plating treatment are different, but all show excellent results in total. Example No.
The test results 1 to 14 will be described.

The example No. 1 has the same S value as the comparative example No. 4.
Although KD61 steel was subjected to electroless plating, the content of B in the plated film was 1.4% by weight, which was within the range of the present invention, and therefore wear resistance, melt damage resistance and heat crack resistance were higher than in Comparative Example No. 4. Both sexes have improved.

The example No. 2 has the same S value as the example No. 1.
Although KD61 steel is subjected to electroless plating, the content of B in the plating film is 3.4% by weight, which is within the range of the present invention, which is a more preferable range. Therefore, the melting resistance was improved as compared with Example No1.

The example No. 3 has the same S value as the example No. 2.
KD61 steel is electroless plated and B in the plating film
The content of is within the range of the present invention, and is a value in an even more preferable range. Further, the content of WC, which is a carbide, is 4.
It is within the range of the present invention at 5% by weight, which is an even more preferable range. Therefore, the surface strength is improved and
Wear resistance and heat crack resistance were improved as compared with o2.

In Example No. 4, SKD61 steel was electroplated, and the contents of B and WC in the plated film were within the range of the present invention, and more preferably within the range. Further, the content of SiO ₂ as an oxide is 4.8% by weight, which is within the range of the present invention. As described above, since both the carbide and the oxide are contained, the wear resistance and the melt damage resistance are extremely excellent.

In Example No. 5, SKD61 steel was electroplated, and the contents of B and WC in the plated film were within the range of the present invention, which is a more preferable range.
Further, the plating film was formed such that the B and WC concentrations were higher toward the surface layer side of the plating film. For this reason, the strength of the plating film on the surface layer side was improved, and the heat crack resistance was significantly improved as compared with Example No. 4.

In Example No. 6, SUS304 steel, which is an austenitic alloy, is electroless plated, and the content of B in the plated film is within the range of the present invention, which is a more preferable range. As a result, the molten metal resistance was improved, and the mechanical properties and melt damage resistance were favorable. However, although it is not so good in terms of wear resistance and heat crack resistance, it has characteristics that it can be sufficiently used as a casting member. Further, since the austenitic alloy has a smaller thermal conductivity than that of the SKD61 steel, the heat retaining property was good.

In Example No. 7, SUS304 steel was electroplated, and the contents of B and WC in the plated film were within the range of the present invention, which is an even more preferable range. Therefore, the surface strength of the plating film is improved, and
Compared with o6, abrasion resistance and heat crack resistance were improved, and melting resistance was extremely excellent. Note that, unlike electroless plating, electroplating can form a thick film, so in this example, a plated film having a thickness of 250 μm was formed.

In Example No. 8, A286 alloy steel, which is an austenitic alloy containing an age hardening element, was electroplated, and the contents of B and carbide ZrC in the plated film were within the range of the present invention. Is the value of. In addition, before the plating treatment, the temperature of 720 ° C.
An aging treatment for holding the time was performed. Therefore, in this example, the mechanical properties and the melting resistance were extremely excellent, and the abrasion resistance and the heat crack resistance were also good results.

In Example No. 9, a titanium alloy was subjected to electroless plating, and the content of B in the plating film was within the range of the present invention, which is a more preferable range. Since the titanium alloy itself has extremely excellent mechanical properties, the mechanical properties of the test material according to this example were also extremely excellent. Further, although it cannot be said that the wear resistance is excellent, it has a property that it can be sufficiently used as a casting member, and both the melt loss resistance and the heat crack resistance were good results. Further, the titanium alloy has a smaller thermal conductivity than the SKD61 steel and has an extremely excellent strength, so that the heat retaining property and the lightweight property are good results.

In Example No. 10, the titanium alloy was subjected to electroless plating, and the contents of B and WC in the plated film were within the range of the present invention, which is a more preferable range. Since the plated film contains carbide,
Wear resistance and melt resistance were improved as compared with o9.

In Example No. 11, the titanium alloy was electroplated, and the contents of B and WC in the plated film were within the range of the present invention, and the values were even more preferable.
In addition, since the plating process was electroplating, the thickness of the plated film could be formed extremely thicker than that of Example No. 10. Therefore, the heat crack resistance was improved as compared with Example No. 10.

In Example No. 12, the titanium alloy was electroplated, and the contents of B and WC in the plated film were within the range of the present invention, and the values were even more preferable.
Further, it contains a predetermined amount of SiO ₂ which is an oxide. Therefore, the surface strength of the plating film is improved, and Example No. 11
The wear resistance was improved compared to.

In Example No. 13, a titanium alloy is electroplated, and the contents of B and WC in the plated film are within the range of the present invention, and are values in a more preferable range.
Further, the plating is performed so that the concentration of B and WC becomes higher toward the surface layer side of the plating film. When such plating is applied, the strength and erosion resistance on the surface side of the plated film are improved. Therefore, the heat crack resistance was improved as compared with Example No. 12, and the other properties were also extremely excellent.

In Example No. 14, a titanium alloy was electroplated, and the contents of B, WC and Cr ₃ C ₂ in the plated film were within the range of the present invention, and values in a more preferable range. Further, the plating is performed so that the concentration of B and WC becomes higher toward the surface layer side of the plating film. This example is similar to Example No. 13 in mechanical properties, wear resistance,
It is extremely excellent in all of melting resistance and heat crack resistance, and since the base material is a titanium alloy, it also has good results in heat retention and light weight.

[0067]

As described above, according to the present invention,
By forming a plating film having a predetermined component composition on the surface of the base material, it has melting loss resistance, welding resistance and heat crack resistance, as well as excellent mechanical properties and wear resistance, and is also good. It is possible to manufacture a casting member having excellent heat retention and light weight.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C22C 38/58 C22C 38/58

Claims (8)

[Claims] 1. A substrate, and one or more elements selected from the group consisting of Ni, Co, Cr and Fe formed on the entire surface or a part of the surface of the substrate: 30% by weight or more in total.
B: 1% by weight or more of an alloy plating film containing the casting member. 2. The casting member according to claim 1, wherein the plated film contains 3% by weight or more of carbide particles. 3. The casting member according to claim 1, wherein the plating film contains 3 wt% or more of oxide particles. 4. The casting member according to claim 1, wherein the plating film has a higher content of B, carbide or oxide on the surface side. 5. The casting member according to claim 1, wherein the base material is made of an austenitic alloy. 6. The casting member according to claim 1, wherein the base material is made of titanium or a titanium alloy. 7. Ni, Co, Cr and F are formed on the surface of the base material.
one or more elements selected from the group consisting of e: 3 in total
A method for producing a casting member, comprising a step of forming an alloy film containing 0% by weight or more and B: 1% by weight by wet plating. 8. The method for manufacturing a casting member according to claim 7, wherein the wet plating is electroplating.