JPH0320428A - Alloy for high strength die - Google Patents

Abstract

PURPOSE:To obtain the alloy for a high strength die having excellent mechanical strength and easy to cast by specifying the compsn. constituted of Zn, Mn, Fe, Al, Ni, Co, Ti, Zr and Cu with inevitable impurities. CONSTITUTION:The alloy for a high strength die is formed from, by weight, <=2% Zn, 0.5 to 3% Nn, 0.5 to 5% Fe, 0.5 to 10% Al, 0.01 to 5% Ni and/or Co, <=0.5% Ti and/or Zr and the balance Cu with <=0.5% inevitable impurities, which secures mechanical strength and has improved castability. The alloy has high content of Cu having high heat conductivity in the components and is therefore suitable particularly to a structural material such as a die for plastic molding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-strength mold alloy suitable for use as a constituent material of plastic molds and the like. [Prior Art] In recent years, the housings, structural parts, etc. of various types of equipment, such as office equipment, have been made of plastic, and these equipments have undergone frequent model changes in order to improve their performance. Along with this, the molding cycle of plastic molded products has become shorter, and high-mix, low-volume production is being implemented. For this reason, materials that are easy to cast and process are required as structural materials for plastic molds. Conventional plastic molds, especially injection molds, are made of metals such as pig iron and cast steel. Although these metals have excellent mechanical strength, they
Difficult to process. That is, cast iron and II steel require large-scale equipment for rust forming due to their high casting temperatures. or,
Simple casting is done in a sand mold, but in this case the casting temperature is as high as approximately 1500°C, resulting in a rough surface of the cast product, which requires a large number of man-hours for surface polishing. In addition, in order to manufacture precise molds, a large amount of time is required for machining such as cutting and electrical discharge machining. Therefore, in recent years, zinc-based alloys and copper-based alloys have been used as structural materials for plastic molding molds, which have low casting temperatures and are easy to cast/process. Zinc-based alloys are JIS H5
Zinc alloy for gui casting specified by 301 (znc-i
), and in addition to Zn, it also contains Al, Cu, M
Contains g. In addition, copper-based alloys, for example,
As shown in Japanese Patent No. 6-11380, in addition to Cu, A
1, Fe%Mn, etc. [Problem M to be solved by the invention] However, the conventional zinc-based alloys and copper-based alloys described above have insufficient mechanical strength and hardness. That is, when these alloys are used as constituent materials for plastic molds,
There is a risk of cracks occurring on the mold surface. Furthermore, as the molding process is repeated using this alloy, the dimensional accuracy of the mold decreases and there is a risk of cracks occurring in the plastic product.For this reason, this mold can only be used for prototype molding. Can not. An object of the present invention is to provide a high-strength metal mold alloy that has excellent mechanical strength and is easy to cast/process. [Means for Solving the Problems] The high-strength mold alloy according to the present invention has a weight percentage of
Zn 2% or less, Mn 0.5~3%, Fe 0.5~
5% Al, 0.5-10% Al, 0.01-5% Ni or Co, or a mixture of both, 0.5% or less of Ti or Zr, or a mixture of both, and the balance is Cu and 0.5%.
% or less of unavoidable impurities. [Function] 'According to the alloy of the present invention, Cu. Since Aj2 is the main component, mechanical strength can be ensured and casting/processability can be improved. Furthermore, mechanical strength and hardness are improved by adding Mn, Zn, Fe, Ti, Zr, or a mixture of both, and oxidation resistance is improved by adding Ni or Co or a mixture of both. .

Impurities such as PB have low solubility in Cu,
It is necessary to keep the concentration as low as possible because it precipitates at grain boundaries and has a negative effect on corrosion resistance. The reason for limiting the composition of the alloy as described above will be explained below. ■82 content^2 has the effect of improving mechanical strength by alloying with Cu. The effect is that if the content exceeds 10%, brittleness increases, and if it is less than 0.5%, the desired strength-improving effect cannot be obtained, so the content was set at 0.5 to 10%. ■Zn content Zn has the effect of improving machinability, but if the content is excessive, it reduces mechanical strength. The amount required to produce an effect was set at 2% or less. ■Mn content Mn has the effect of improving mechanical strength, but if the content is less than 0.5%, the desired strength improvement effect cannot be achieved, while if the content exceeds 3%, it will become brittle. From doing that,
It was set at 0.5-3%. ■Fe content Fe has the effect of improving mechanical strength and hardness, but if the content is less than 0.5%, it has no effect, and if it is more than 5%, it becomes brittle, so it is set at 0.5 to 5%. Ta. ■Content of Ni or Co or a mixture of both NL or Co or a mixture of both has the effect of improving corrosion resistance and hardness, but no effect can be obtained if the content is less than 0.01%. In addition, if the content exceeds 5%,
0.0 to make it brittle. It was set at 5%. ■Content of Ti, Zr, or a mixture of both Ti, Zr, or a mixture of both has the effect of improving mechanical strength and hardness when added in small amounts, but excessive addition causes decomposition, so the content should be 0.5% or less. It was determined that That is, in the alloy of the present invention, by mixing the above-mentioned metal elements in the above-mentioned contents, mechanical strength and surface hardness can be increased, and casting/processability can be improved. [Example] Table 1 shows the tensile strength and hardness of the alloy of the present invention in comparison with a comparative alloy. Cu-Zn- An -Fe-Mn- with the composition shown in Table 1
After creating Ni(Go)-Ti(Zr)-based alloys A-E of the present invention and confirming that each component was uniformly dissolved, JI
A tensile test piece shown in Reference Diagram A of S H 5301 was prepared. Regarding these tensile test pieces, JIS Z 2241
A tensile test was conducted in accordance with the regulations, and their tensile strength at break was determined.

In addition, the Brinell hardness of each of the above alloys was measured according to JIS Z 2243. The results are shown in Table 1.

Furthermore, the tensile strength and hardness of Comparative Alloy F-I shown in Table 1 were also measured by the same method as above. Comparative alloy G is a die-cast zinc alloy (ZDC-1) specified by JIS Fl 5301, comparative alloy H is a zinc alloy for vJ mold making (ZAS) manufactured by Mitsui Mining & Co., Ltd., and comparative alloy is specified by JIS H 5101. Brass casting (YBsC)
1).

According to Table t, it is recognized that the alloy of the present invention has lower tensile strength and hardness than the comparative alloy. In addition, the alloy of the present invention has a relatively low melting point of approximately 1000°C compared to cast iron and cast steel, and has good casting/processability. Therefore, high-strength molds can be manufactured in a relatively short time, and injection molding is possible. It is recognized that it is very useful as an alloy for carving molds, etc. Furthermore, as is clear from its composition, the alloy of the present invention has a large content of Cu, which has a high thermal conductivity, and therefore has the advantage of requiring less time for heating and cooling.

This means that when used as a mold for plastic injection molding, the molding time is shortened, making it extremely useful as an alloy for injection molding. [Effects of the Invention] As described above, according to the present invention, it is possible to obtain a high-strength mold alloy that has excellent mechanical strength and is easy to cast/process.

Claims (1)

[Claims] (1) Zn 2% or less, Mn 0.5 to 3 in weight percent
%, Fe0.5-5%, Al0.5-10%, 0.01
~5% Ni or Co or a mixture of both, 0.5
% or less of Ti or Zr, or a mixture of both, and the balance is Cu and 0.5% or less of unavoidable impurities.