JPS63290235A - Ni based cast alloy for dentistry - Google Patents

Abstract

PURPOSE:To provide excellent wear resistance, corrosion resistance and toughness to the titled alloy and to improve the castability thereof by incorporating specific amounts of Si, Mn, Cr, Mo and Hf into the Ni based alloy. CONSTITUTION:The compsn. of the Ni based cast alloy for dentistry consists of, by weight, 0.1-6% Si, 0.1-3% Mn, 20-37% Cr, 1-20% Mo, 0.005-6% Hf and the balance Ni with inevitable impurities. 0.1-10% W and one or more kinds among 0.1-12% Ti, Nb and Ta are furthermore incorporated into the alloy at need. Said alloy is prepd. by using a conventional high-frequency melting furnace and is cast by using a sand mold, etc. Since said cast alloy has high strength, high hardness and high toughness equal to or above the conventional Ni-Cr based alloy and has excellent castability, the cast having a complicated shape can soundly be produced with a fine cast case.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides dental N, which has the properties required for dental parts such as dental beds and crowns, and which has excellent castability.
This relates to i-base casting alloys.

[Conventional technology]

In general, the above-mentioned dental components have strength that does not deform due to pressure during occlusion when actually installed in the oral cavity, corrosion resistance that does not corrode due to secretions in the oral cavity, etc., and is ground after being cast. Since properties such as toughness while maintaining a certain degree of hardness are required, Ni-Cr based casting alloys having these properties are used in the manufacture of these members.

[Problem that the invention seeks to solve]

However, this conventional dental Ni-Cr-based casting alloy has an extremely high melting point and poor flowability.
When casting, due to the complex shape of the casting, it is necessary to raise the temperature of the molten metal when casting, which tends to cause seizure between the molten metal and the mold, making it difficult to produce a casting with a clean casting surface. The finishing grinding required considerable effort and time.

[Means for solving problems]

Therefore, from the above-mentioned viewpoint, the present inventors focused on the above-mentioned Ni-Cr-based casting alloy, which has the properties required for dental components, and found that it has excellent castability, that is, a relatively low melting rate. We conducted research to develop an alloy that exhibits excellent flowability even when cast at high temperatures, and can produce complex-shaped castings with clean casting surfaces and in a sound manner. indicates weight %).

Si: 0.1-6%, Mn: 0.1-3
%.

Cr: 20-37%, MO=1-20%.

Hf: 0.005-6ch.

and, if necessary, W: 0.1 to 10%, one or more of Ti, Nb, and Ta, and 0.1 to 12%, or both. The Ni-based casting alloy has the strength, corrosion resistance, toughness, and hardness required for dental parts, has good flowability, and has excellent castability. Because it is excellent,
They discovered that dental components with complex shapes can be manufactured with clean casting surfaces.

This invention was made based on the above knowledge, and the reason why the component composition was limited as described above will be explained below.

(a) In addition to having a deoxidizing effect, the 5i Si component also has the effect of lowering the melting point of the alloy, improving flowability, and thereby improving castability, but if its content is less than 0.1%, The desired effect cannot be obtained in the above action, and on the other hand, if the content exceeds 6%, %C
Since the toughness of the alloy decreases in relation to the r content, the content was determined to be 0.1 to 6.

(b) Mn The Mn component has many deoxidizing effects like the Si component, and
It forms a solid solution in the base material and has the effect of stabilizing the austenite in the base material, but if the content is less than 0.1%, the desired effect cannot be obtained; on the other hand, if the content exceeds 3%, This is not to say that the effect of further improvement cannot be obtained due to the above action, but rather that the corrosion resistance tends to deteriorate, so the content is set at 0.1 to 3.

(c) Cr A part of the Cr component dissolves in the base material, strengthens it, improves its strength, and has the effect of significantly improving corrosion resistance. However, if its content is less than 20%, the above-mentioned The desired effect could not be obtained, and on the other hand, if the content exceeds 37%, the toughness tends to decrease, so the content was set at 20 to 37%.

(d) M.

Like the Cri component, the Mo component also has the effect of forming a solid solution in the base material, strengthening it, and improving the strength.

If the content is less than 1%, the desired strength and hardness cannot be secured, while if the content exceeds 20%, the toughness of the alloy will decrease. %.

(e) Hf The Hf component is a solid solution in the austenite matrix formed mainly by Ni and Cr components, improving toughness and strength, lowering the melting point of the alloy and improving flowability, thereby improving castability. However, if the content is 0. If the content is less than OO51, the desired effect cannot be obtained in the above action, and on the other hand, if the content exceeds 6%, no further improvement effect will be obtained. It was determined that

(f) Like the Cr and MO acid components, the W component has the effect of forming a solid solution in the base material, strengthening it, and improving its strength, so it is especially necessary when these properties are required. However, if the content is less than 0.1 inch, the desired effect of improving the above action cannot be obtained.

On the other hand, if the content exceeds 10%, the toughness decreases, so the content was set at 0.1 to 10%.

(g) Ti, Nb, and Ta These components have the effect of significantly suppressing the growth of crystal grains in the base material and, in fact, making the crystal grains finer. Although it is contained in
If the content is less than 0.1%, the desired effect of improving the above action cannot be obtained, while if the content exceeds 12%, the toughness of the alloy will decrease.
It was set at 12%.

Note that Zr may be contained as an unavoidable impurity, but if its content exceeds 0.3%, it will have an adverse effect on toughness and castability.

The Zr content must not exceed 0.3%. Also, depending on the melting raw material used, it may contain Fe and Co, but there is no problem as long as each content is up to 3%.

〔Example〕

Next, the Ni-based casting alloy of the present invention will be specifically explained using examples.

Using an ordinary high-frequency melting furnace, in the atmosphere, Ni-based casting alloys 1 to 23 of Table 2 of the present invention and conventional Ni-based casting alloys having the compositions shown in Table 1, respectively. A molten metal was prepared and then cast into a sand mold to produce a test piece for measuring hardness, a test piece for measuring tensile strength, and a material for measuring melt flow.

Next, using these test pieces, we measured Vickers hardness at room temperature in order to evaluate wear resistance, and tensile strength, 0.2% proof stress, and elongation in order to evaluate strength and toughness. However, in order to further evaluate the castability, the above-mentioned material was heated and melted at a relatively low temperature of 1450°C, where almost no reaction with the mold occurs, and immediately after reaching this temperature, a mold made of phosphate material was melted. Diameter formed inside: 0.5+u
Casting was performed in a cavity having dimensions of +φ×length=70 mm in an argon atmosphere using a small-sized high-tube wave centrifugal casting machine, and the melt flow length was measured for each. The results of these measurements are shown in Table 2. In addition, what is the evaluation of castability?

If the flow length of the hot water is less than 30u, mark it with an X, 30~501
A score of 0 was given when the score was less than 113, and a score of O was given when the score was 50IIIJ1 or more.

〔Effect of the invention〕

From the results shown in Table 2, the Ni-based cast alloys 1 to 1 of the present invention
All of No. 23 have high hardness, high strength, and high toughness that are equal to or higher than conventional Ni-based casting alloys, and have even better castability than the conventional Ni-based casting alloys. it is obvious.

As described above, the Ni-based casting alloy of the present invention not only has the excellent wear resistance, corrosion resistance, and toughness required for dental parts, but also has even better castability, which is essential for the production thereof. .

Claims (4)

[Claims] (1) Si: 0.1-6%, Mn: 0.1-3%, Cr
: 20 to 37%, Mo: 1 to 20%, Hf: 0.005 to 6%, and the remainder is Ni and unavoidable impurities (weight %). Base casting alloy. (2) Si: 0.1-6%, Mn: 0.1-3%, Cr
:20 to 37%, Mo: 1 to 20%, Hf: 0.005 to 6%, and further contains W: 0.1 to 10%, with the remainder consisting of Ni and inevitable impurities. (or more by weight). (3) Si: 0.1-6%, Mn: 0.1-3%, Cr
: 20-37%, Mo: 1-20%, Hf: 0.005-6%, and further contains one or more of Ti, Nb, and Ta:
1. A dental Ni-based casting alloy characterized by having a composition (weight %) of 0.1 to 12%, with the remainder consisting of Ni and unavoidable impurities. (4) Si: 0.1-6%, Mn: 0.1-3%, Cr
:20 to 37%, Mo: 1 to 20%, Hf: 0.005 to 6%, furthermore, W: 0.1 to 10%, and one or more of Ti, Nb, and Ta. 2 or more types:
1. A dental Ni-based casting alloy characterized by having a composition (weight %) of 0.1 to 12%, with the remainder consisting of Ni and unavoidable impurities.