KR810000409B1 - Resistant corrosion white copper alloy - Google Patents

Abstract

The high strength white Cu-Mn-Zn alloy having the high resistant corrosion contains Mn 10-25%, Zn 10-25%, Ni 0.2-10%, Al 0.5-3%, Fe 0.2-2%, Pb 0.5-3.5% and balance Cu, and its melting point is 830-900≰C.

Description

Corrosion Resistance Strong Copper Alloy

The present invention relates to the improvement of corrosion resistance, strength improvement and color improvement of Cu-Mn-Zn (copper-manganese-zinc) based alloys.

Conventionally, copper, white, cupronickel, and bronze are commonly used for copper alloys that exhibit white color. However, as shown in Table 1, architectural ornaments from high melting point, difficult casting work, and high price There are many examples of using chrome plating mainly on brass.

However, the chrome plated on the brass is released from the surface after a certain period of time, so that the brass surface is often stained and its value as an ornament is often damaged.

In recent years, due to the pollution on the human body of the chrome tends to avoid the chromium plating, and the development of a new white copper alloy that can be used without chromium plating instead of brass has been called for.

TABLE 1

The present invention provides a copper alloy that satisfies such a request. Since the light is white and the corrosion resistance is high, there is no need for chromium plating, and the melting point is low and the castability and workability are good. Its characteristics are far superior to brass and bronze, and it is characterized by its safety.

When manganese or manganese + zinc (Mn + Zn) is added to copper, melting | fusing point of the alloy will fall remarkably, and it shows white in some composition ranges.

It is expected that many metallurgists may have given up to discoloration due to de-zinc and de-manganese in use, even though many metallurgists have not yet thought or discovered such alloys.

For example, alloys formed from Mn 15-35%, Zn 10-25% and the rest of Cu have a considerably lower melting point in the range of 830-900 ° C and are white, but this is tap water, sea water It discolors easily by sea water or weak alkaline aqueous solution, and has a big drawback in a building decorative member.

The present inventors have conducted various studies for many years to recover the above defects, Mn 15-35%, Zn 10-25%, Ni 0.2-10%, Al 0.2-3%, the alloy of the remaining Cu is white It succeeded in inventing a white copper alloy which exhibits good corrosion resistance and good mechanical properties.

It was recognized that the melting point of the alloy of the present invention was in the range of 830-900 ° C., which was remarkably low compared to conventional white copper alloys such as nickel silver and cupronickel, and was extremely good in castability.

The color tone of the alloy of the present invention is white and hardly discolored with respect to tap water and weak alkaline aqueous solution.

Moreover, the mechanical property and workability are also favorable, and many uses are expected as a extending | stretching material or a structural material.

Therefore, the alloy of the present invention is believed to be particularly effective in plating as an internal structural solvent for building decorative members, vehicles, ships, and the like, and to have a large industrial effect.

Next, the reason for limitation of member elements in the alloy of the present invention will be described.

-Mn 의 석출에 의한 합금의 체적수축이 현저하여 주조시에 균열을 수반하는 경향이 있으므로 Mn농도의 상한(上限)은 Mn 35%가 적절하다.Mn: At 15% or less of Mn, the melting point is increased, and the color tone is not completely white. It is difficult to dissolve at 35% or more of Mn.

Since the volumetric shrinkage of the alloy due to precipitation of -Mn is prominent and tends to be accompanied by cracking during casting, the upper limit of Mn concentration is preferably 35%.

Zn: Zn should be 10% or more in order to prevent the generation of pores during melting casting, to lower the melting point and to maintain the color tone. However, if the Zn concentration is 25% or more, the surface becomes rough during casting and the mechanical strength is lowered, so the upper limit of the Zn concentration is 25%.

Al: Al should be at least 0.2% because Al improves the fluidity of molten metal and raises the alloy strength. However, when the Al concentration is 3% or more, the stretching of the present alloy is greatly reduced and cracking occurs during casting, so the upper limit of Al concentration is suitably Al 3%.

Ni: Ni is a member element which plays the most important role in keeping the color tone of the alloy of the present invention white, and is also an element necessary for remarkably improving the corrosion resistance. However, when the Ni concentration is 0.2% or less, it is difficult to expect such an effect, and as the Ni concentration is increased, the corrosion resistance of the alloy of the present invention is remarkably improved, but when the concentration is 10% or more, the melting temperature exceeds 920 ° C, that is, bronze It becomes equal to the melting point of and thus the effect of low melting point is reduced.

In addition, since Ni is expensive, if too much loses the practicality of the alloy of the present invention, the upper limit of Ni concentration is preferably 10% Ni.

The alloy of the present invention can add up to 5% lead (pb) when free machinability is required. In addition, it is possible to add up to 2% Fe in order to increase the fatigue limit and improve the high temperature properties.

When the grain size of the alloy of the present invention is required to be fine, 2.5% of Ti may be added.

Next, Table 2 shows examples of the inventive alloy and its effects.

TABLE 2

Salt spray test condition 35 ℃, 5% NaCl, 24 hours (No. 10 12 is 72 hours)

Claims (1)

A white copper alloy, characterized by Mn 10-25%, Zn 10-25%, Ni 0.2-10%, Al 0.5-3%, Fe 0.2-2%, Pb 0.5-3.5%.