JPS63203221A - Metallic die - Google Patents

Abstract

PURPOSE:To improve the durability and profitability of a die by integrally coating the alloy layer of corrosion resistance, wear resistance and heat resistance dispersing a carbide on the material working face of the die using a metal material. CONSTITUTION:As correction, wear and heat resistant alloy, the alloy dispersing the carbide of the element of group IVA, VA and VIA of a periodic table or one kind or more than two kinds of carbide selected from among the compound carbide with these carbides as the basic components on the ground of Ni base or Co base alloy is taken. The alloy layer is formed by subjecting the mixture of one kind or more than two kinds of compound carbides to build up welding by powder building-up or integrally sintered by HIP sintering. At this time, the grain size of the carbide is taken in the range of 5-300mum and the mixing amt. of the carbide in the range of 10-80% at volume ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a mold having excellent corrosion resistance, wear resistance, and heat resistance.

[Conventional technology]

In recent years, with the advancement of technology, dimensional control of molded products using molds has become increasingly strict.

Along with this, high-grade materials with excellent wear resistance and corrosion resistance have become desirable as mold materials.

Conventionally, tool steel, especially 5KD-11,
Although a material such as 5KD-61 is generally used, the current situation is that this material cannot meet the above requirements.

As a result, WC-Co-based cemented carbide alloys have come to be used in some fields, but this alloy has problems with corrosion resistance and is extremely expensive, limiting the fields of use. . Therefore, there is a need for a mold material that has excellent corrosion resistance and wear resistance, is inexpensive, and is versatile.

[Problem that the invention seeks to solve]

The present invention has been made in view of the above circumstances, and its purpose is to provide a mold with a new structure that is inexpensive, versatile, and has excellent corrosion resistance, wear resistance, and heat resistance.

[Means for solving problems]

The inventor of the present invention obtained the following knowledge as a result of intensive research regarding the above problem. The present invention was made based on this knowledge.

(1) Corrosion-resistant, abrasion-resistant,
The above-mentioned problems can be solved by using a mold with a so-called composite structure, in which a layer of heat-resistant alloy is integrally coated.

(2) Corrosion-resistant, wear-resistant, and heat-resistant alloys with dispersed carbides include carbides of elements in groups rVA, VA, and VIA of the periodic table, or carbides of these carbides as basic components, on a base of Ni-based or Go-based alloys. It is preferable to use an alloy in which one or more types of carbides selected from composite carbides and medium are dispersed.

(3) To form the above-mentioned coating layer, Ni-based or Co-based alloy powder and carbides of Group IVA, VA, and VIA elements of the periodic table, or one type of composite carbide containing these carbides as basic components, are used. Alternatively, a method of welding a mixture of two or more types of powder by powder overlay or a method of integrally sintering by HIP sintering is effective.

(4) The grain size of the carbide is preferably in the range of 5 to 300 μm.

(5) The amount of the carbide mixed is preferably in the range of 10 to 80% by volume.

[For production]

The machined surface of the mold material may have an extremely complex curved surface, and in order to form a thin and uniformly thick alloy layer on such a machined surface, overlay welding or HIP sintering is the most preferable method. It is.

In order to perform overlay welding or HIP sintering, the alloy forming the base material must not only be corrosion resistant, wear resistant, and heat resistant, but also be able to be fused or sintered to the base material at a temperature below the melting point of the mold base material, and also be carbide-resistant. It is necessary to have a good sense of familiarity.

It is with this consideration in mind that Nii and CojJ alloys were selected as the base components of the present invention.

There are various combinations of ingredients other than Co.
For example, the following combinations are effective.

Cr: 5.0-20. Owt, % It dissolves in solid solution in the base and is effective in improving the hardness of the base, and also combines with C to form carbide to improve wear resistance. However, if it is less than 5.0%, wear resistance and corrosion resistance are insufficient.
If it exceeds 20.0%, it becomes brittle, which is not preferable.

The most preferred range is 10.0-18.0%.

B:1. Q~5.0 0% High hardness boride is precipitated in the composition, which is effective in increasing the hardness of the alloy and improving wear resistance, and furthermore, has the effect of lowering the melting point.

However, if it is less than 1%, sufficient hardness cannot be achieved, the melting point becomes high, and it becomes easy to crack during cooling after overlaying or sintering. Moreover, if it exceeds 5.0%, the alloy becomes brittle and easily cracks, which is not preferable.

The most preferred range is 2.4-4.0%.

Fe: 10% or less is effective in improving the toughness of the base, but if it exceeds 10.0%, it is not preferable because it reduces the hardness of the base and also reduces the corrosion resistance.

The most preferred range is 3-6%.

Si: 0.5-5.0% Effective for increasing the hardness of the base, and also necessary as a deoxidizing element. However, if it is less than 0.5%, the necessary hardness cannot be obtained, and if it exceeds 5.0%, the toughness deteriorates, which is not preferable.

The most preferred range is 2.0-4.0%.

C: 2.0% or less It forms a solid solution in Ni or Co to increase strength, and also combines with alloying elements to form carbides to improve wear resistance. However, if it exceeds 2.0%, it is not preferable because it reduces toughness.

The most preferred range is 0.4-1.0%.

In the present invention, carbides of Group IVA, VA, VIA elements of the periodic table, or
1 selected from composite carbides containing these as basic components
Seeds or two or more types of carbides are dispersed.

These carbides are highly hard carbides and provide sufficient wear resistance to the alloy after overlaying or sintering, but carbides having a specific gravity of 6.5 to 8.5 are most preferred.

When the specific gravity is within this range, the carbide contains Ni groups, Co
It can be evenly dispersed in the base alloy matrix (specific gravity approximately 7.5).

Moreover, if 30 volumes or more of the total amount of carbide is made up of this carbide, even if the remaining carbide has a specific gravity outside the above range, the dispersibility of the entire carbide will hardly be hindered.

The particle size of the carbide used is preferably in the range of 5 to 300 microns. If the thickness is less than 5 μm, excessive solid solution may occur in the base material during build-up or sintering. Also, 300μ
If it exceeds m, cracks tend to occur in the built-up layer or sintered layer, which is not preferable.

The amount of carbide mixed is preferably in the range of 10 to 80% by volume, but when forming an alloy layer by overlay welding, it is preferable to suppress the upper limit to 50%.

This is because overlay welding becomes excessively sensitive to cracking if it exceeds 50%.

In the case of HIP sintering, it is relatively safe against cracking even if it is added up to 80%.

The corrosion-resistant and wear-resistant alloy layer obtained in the above manner is
It is formed by overlay welding or HIP sintering, so
It is firmly bonded to the mold base material through the diffusion layer and has high peeling resistance.

Next, the base material of the mold of the present invention will be described.

The overlay layer or sintered layer of the present invention is not only made of a material that is brittle and easily cracked, but also has carbide particles dispersed therein, making it difficult for cracks to occur due to tensile stress during cooling. .

On the other hand, carbon steel for mechanical structures, alloy steel, and various other steel materials can be used as the mold base material depending on the application, but austenitic stainless steel is the best choice from the viewpoint of preventing cracks. It's advantageous. That is, since the base material has a large coefficient of thermal expansion (contraction), it can sufficiently follow the contraction of the built-up layer or the sintered layer. Furthermore, since no transformation occurs during cooling and the austenitic state remains, the plastic deformability is large and is advantageous in preventing cracking.

As described above, the overlay welding method and the HIP sintering method are preferred methods for forming the alloy layer of the present invention.Next, these methods will be described.

(1) Overlay welding method Using gas or plasma as a heat source, the above-mentioned powder material is blown onto the welding area, and the base metal (Ni-based, C, etc.) is used using the same heat source or another heat source.

This is a method in which the base alloy (base alloy) is melted and blended with the base metal and carbide to integrate them.

(2) HIP sintering method A canning material made of an iron plate is placed on the processed surface of the mold base material at a distance without contacting it, and after sealing one end of the bottom and side surfaces with a sealing material, the other end is The mixture of raw material powders described above is filled from one side of the container, and after degassing, the other end of the mixture is also sealed.

Next, this is subjected to hot isostatic pressure sintering (HIP sintering), and the raw material powder is pressed against the mold base material by the pressure applied to the canning material, and sintered.

After sintering, the canning material is removed and the mold is finished to a predetermined size.

〔Example〕

The structure of the present invention will be explained with reference to the drawings.

FIGS. 1(a) and 1(b) are diagrams illustrating the structure of a mold according to an embodiment of the present invention.

1 is a mold base material, and 2 is a layer of a corrosion-resistant, wear-resistant, and heat-resistant alloy coated on the base material 1.

The alloy layer 2 is made of an alloy in which carbides of Group 1'/A, VA, and VIA elements of the periodic table or composite carbides containing these carbides as basic components are dispersed in a base of Ni-based and Co-based alloys, It is metallurgically joined to the base material 1.

In coating the mold base material 1 with the alloy layer 2, the base material 1
In some cases, the base metal is rough-machined into a mold curved surface in advance and the alloy layer is coated on this surface, and in other cases, the base material is left unprocessed (flat).
There are cases in which an alloy layer is coated on this to a required thickness and the curved surface of the mold is post-processed on this coating layer, and there are cases in which both are combined. FIG. 1(a) shows the case where the base material has been processed in advance, and is effective for molds with severe undulations on the curved surface. Figure 1 (bl) shows the case where the base material is coated unprocessed and processed later, which is advantageous for molds with relatively flat curved surfaces.

Next, a specific example will be described in which a mold having the structure shown in FIG. 1(a) is manufactured by HIP sintering and overlaying.

Example 1: When using HIP sintering A specific procedure for carrying out the present invention using HIP sintering will be explained with reference to FIG.

1 is the mold base material, 2 is the canning material, 3 is the side sealing material that seals the gap between the side surfaces of the canning material and the base material, and 4 is the sintered raw material powder filled in the gap between the canning material and the base material. be.

Mold base material> The mold base material is 1100X100X50 and the material is 30M44
A 0 block was used that had been rough-machined in advance into a cross-sectional shape (maximum groove depth 10 mm) as shown at 1 in FIG.

<Canning Material> As the canning material 2, a mild steel plate having a thickness of 2 mm was previously formed into a cross-sectional shape as shown in FIG. 2 along the curved shape of a mold.

<Sintered alloy> Table 1 shows the composition of the raw material powder for the sintered alloy.

<Filling with raw material powder> In the arrangement shown in Figure 2, mold base material 1 and canning material 2 are placed with a gap of 15 m, leaving a gap on the left side of the figure, and filling the other side with a gap of 15 m. The gap was sealed with a side sealing material 3, and the remaining left gap was filled with raw material powder 4. After filling, it was degassed, and the remaining gap was sealed. This is shown in column 1 of Table 1 above.
The test was conducted for each of the 6 compositions.

<HIP sintering> Pressure 1100 kg/co? , HIP sintering was performed at a temperature of 980°C.

After sintering, each canning material was mechanically removed and the mold was finished to the predetermined dimensions. For each of the molds of 11 kL 1 to 6, the state of bonding between the sintered alloy and the mold base material and the state of dispersion of carbides were investigated.

The joining condition was that each mold was completely sintered as one piece.

The dispersibility of carbide was generally good for each mold, especially for NcL3.
, fish 5.11k16 was excellent.

Moreover, no cracks were observed in any of the sintered layers.

Example 2; Mold base material when using overlay welding> A 100x100x50 block of 5US304 austenitic stainless steel was used as the mold material, and the cross-sectional shape shown at 1 in Fig. 3 (maximum groove depth 10 m) was used as the mold material. ) was rough-processed in advance and used as the base material.

Overlay alloy〉 Table 2 shows the composition of the raw material powder for the overlay alloy.

Overlay Welding> For each of the compositions Nos. 1 to 6, overlaying was performed to a thickness of 1Q mm by plasma welding to obtain a predetermined dimension, and a mold having a structure as shown in FIG. 3 was manufactured. 7 in the same figure is the mold base material,
2 is a build-up layer.

After the build-up, each of l1kL1 to 6 was examined for the fusion state at the build-up boundary and the dispersion state of carbide.

A diffusion layer was formed at the boundary, and the overlay alloy was completely fused to the base metal.

The dispersibility of carbides is generally good for all alloys, especially for N.
13, magnetic 5, and floor 6 were excellent.

Moreover, no cracks were observed in any of the overlay layers.

[Effects of the Invention] As described in detail above, the present invention is to integrally coat the machined surface of a mold base material with an alloy layer having excellent corrosion resistance, wear resistance, and heat resistance with a thin and uniform thickness. This makes it possible to greatly contribute to improving the durability and economic efficiency of molds.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the present invention in detail. FIG. 2 is a diagram illustrating a specific procedure for carrying out the present invention using HIP sintering. FIG. 3 is a diagram illustrating the structure of a mold when the present invention is implemented using overlay welding. In Fig. 1, 1... Mold base material, 2... Alloy layer In Fig. 2, l... Mold base material, 2... Canning material, 3...
Side sealing material, 4... Raw material powder In Fig. 3, 1... Mold base material, 2... Overlay layer.

Claims (4)

[Claims] (1) A mold having a structure in which a material processing surface of a mold using a metal material as a mold material is integrally coated with a layer of a corrosion-resistant, wear-resistant, and heat-resistant alloy, and the alloy layer is One or more carbides selected from carbides of Group IVA, VA, and VIA elements of the periodic table or composite carbides containing these carbides as basic components are dispersed in a base of Ni-based or Co-based alloy. A mold characterized by being made of a metal alloy. (2) The alloy layer is made of powder of Ni-based or Co-based alloy, carbide of Group IVA, VA, or VIA elements of the periodic table, or powder of one or more composite carbides containing these as basic components. The mold according to claim 1, which is formed by overlay welding or HIP sintering. (3) The mold according to claim 1 or 2, wherein the carbide has a particle size of 5 to 300 μm. (4) The mold according to any one of claims 1 to 3, wherein the amount of the carbide mixed is 10 to 80% by volume.