JPS599609B2 - Brass for contacts and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to brass for contacts such as terminals, connectors and switches that have excellent strength and formability, and a method for producing brass for contacts for improving the spring limit value by low-temperature annealing treatment. It is.

Brass is generally excellent in economy, workability, corrosion resistance, conductivity, moldability, etc., and is therefore widely used as a material for electrical parts such as contacts.

However, in recent years, electricity, communication, and electronic equipment have made remarkable progress, and at the same time, they are becoming more diverse, and individual equipment is being pursued to have higher performance, smaller size, longer life, and lower cost.

Therefore, it is desired that the performance of the materials constituting devices be improved in accordance with the above requirements, and contacts are no exception to this rule.

Contactors are usually manufactured by molding a so-called 7/3 brass plate or strip using a press, but the mechanical properties of conventional 7/3 brass make it difficult to form contacts. Improvements have reached their limits, and in order to meet the user's request, we need a material that has high strength, exhibits better formability at the same user-specified strength, and can be easily bent. is desired to appear.

In addition to the strength and moldability of the contactor, the spring limit value is also an issue.

It is known that the spring limit value can be improved by low-temperature annealing as the degree of cold working increases, that is, the higher the strength of the material, but on the other hand, the formability decreases, so a material with a good balance between the two is required. At the same time, thinning is also required.

The present invention has been made based on the above-mentioned circumstances.
The invention of Zn25-38wt, P.O. 0 0
5 to 0.100 wt% and FeO. 005～
Brass for contacts is characterized by containing 0.1 to 00 wt % with the remainder substantially consisting of Cu, and in order to obtain a material with a well-balanced strength and moldability, it is necessary to P and Fe, respectively, were o. oio~0.0
3 Owt%, preferably 0.015 to 0.035 wt%.

Further, as a second invention, a brass ingot having the above-mentioned composition range is hot-rolled and then cold-rolled according to a conventional method.
This is a method for producing brass for contacts, characterized by annealing at 00 to 300°C for 5 to 180 minutes.

Next, the reason for limiting each component contained in the alloy of the present invention will be explained.

Zn has the effect of increasing strength, is cheaper than Cu, and has the effect of improving workability, so the higher the content, the more pronounced the effect, but if it exceeds 38 wt%, the α phase alloy The upper limit was set at 38 wt % because it becomes an (α+β) phase alloy and the workability decreases.

Further, if it is less than 25 wt%, the strength improving effect is insufficient and the Cu content increases, which is not economically desirable.

Even if P and Fe are added alone, their contribution to strength improvement is low.

Regarding P, if it is added below 0.005 wt%, the strength will not be stabilized even if it is co-added with Fe, and the product performance will not be uniform. If it exceeds 0.1.00 wt%, hot workability and other problems will occur. Since workability deteriorates, the upper limit was set at 0.100 wt %.

In order to make a material with balanced strength and workability when co-added with Fe, it is necessary to add 0.010 to 0.030 wt.
It is desirable to add in a range of %.

The reason why Fe is added in the range of 0.005 to 0.100 wt% is that it contributes to strengthening the alloy by being co-added with P, and when workability is also taken into account, it is 0.015 to 0.
．． It is desirable to add it in a range of 0.35 wt%.

If the amount added is less than 0.005 wt%, the strength improvement effect will be insufficient, and even if it is added in excess of 0.100 wt%, equilibrium will be reached, and the melting time will be long to melt Fe, which has a high melting point at the time of melting. It's not economical.

In order to impart the above-described spring properties to the alloy of the present invention, which is an essential requirement as a contact material, it is necessary to perform a low-temperature annealing treatment at 200 to 300°C for 5 to 180 minutes after final cold rolling. .

The reason why the annealing temperature was limited to 200-300℃ is 200℃.
Below 300, the effect of improving the spring limit value is insufficient.
If the temperature exceeds ℃, the spring limit value will decrease rapidly and at the same time the strength will begin to decrease, so care must be taken.

If the annealing time is less than 5 minutes, the effect of improving the spring limit value is insufficient, and if it exceeds 180 minutes, no increase in the effect can be expected.
This is also undesirable from the standpoint of energy conservation.

The present invention will be explained in detail below using examples.

After hot rolling ingots of the present invention alloy and comparative alloy (including known 7/3 brass) having the compositions shown in Table 1 according to a conventional method,
After applying appropriate intermediate annealing, cold rolling is performed to process the material to a predetermined intermediate material, finish annealing is performed at 360° C. for 1 hour, and finish cold rolling is performed at a processing rate of 40% or less. The plate material was adjusted to a thickness of 4 mm.

The results of measuring the mechanical properties of the inventive alloy and the comparative alloy at locations parallel to the rolling direction of the annealed material and the rolled material subjected to 30-cut finish cold rolling using No. 13-B test pieces described in JIS Z 2201 are shown below. Shown in Table 2.

At this time, the annealed material was subjected to finish annealing at 360° C. for 1 hour after cold rolling, and was used as a test material.

According to Table 2, the tensile strength of the alloy of the present invention is increased by more than 10 modulus in the annealed material compared to the known 7/3 brass and the comparative alloy, and the tensile strength is increased by more than 10 modulus in the cold rolled material with a 30 modulus finish. , yield strength is approximately 10% superior, and elongation values are approximately the same.

In other words, it can be said that the alloy of the present invention has an elongation value that greatly affects formability, which is equivalent to that of the conventional alloy, and is an alloy that has excellent strength.

Figures 1 and 2 show a 180° bending test of the alloy of the present invention with a plate thickness of 0.4y++m and a rolled material of known 7/3 brass, and the bending radius (
rrrm)/plate thickness (TML), with tensile strength plotted on the horizontal axis.

In Figure 1, the bending line is parallel to the rolling direction, which has poor workability.
Figure 2 shows the rolling direction perpendicular to the rolling direction, which has good workability, but if the design processing is done above the curve, the
°It shows that bending is possible.

Therefore, the alloy of the present invention is 7/3 of the known alloy from FIGS. 1 and 2.
It can be seen that the tensile strength is 60 kf/1 or more and the bending workability is much better than that of brass.

Next, the tensile strength of the alloy of the present invention and the known 7/3 brass is 60k.
Table 3 shows the results of measuring the spring limit values in the direction parallel to the rolling direction after low-temperature annealing of g/mA plate material (rolled material) at 150 to 300° C. for 1 hour.

According to Table 3, the spring limit value of the alloy of the present invention is 200 to 30
By performing low temperature annealing at 0°C for 1 hour, the known 7/
It is significantly improved compared to low-temperature annealed brass material.

Further, FIG. 3 shows the change in spring limit value with respect to the tensile strength of the alloy of the present invention and the known 7/3 brass after low temperature annealing.

At this time, the low temperature annealing conditions for the alloy of the present invention are 225 to 275
℃ for 1 hour, and the known low-temperature annealing conditions for 7/3 brass were 225° C. for 1 hour.

In FIG. 3, curves A and B are the properties of the alloy of the present invention perpendicular to the rolling direction and parallel to the rolling direction, respectively, and curves C and D are the properties of the known 7/3 brass perpendicular to the rolling direction and rolling direction, respectively. This is a characteristic of a portion parallel to the direction, and shows that the alloy of the present invention has a superior spring limit value in both directions compared to the known 7/3 brass.

As mentioned above, the alloy of the present invention has much better strength and workability than the known 7/3 brass, and as a result, it can be made thinner than conventional contact materials. It can be said that it is extremely suitable as a contact material in the communications and electronics sectors.

In addition, by hot rolling and cold rolling a brass ingot made of the alloy of the present invention according to a conventional method, and then subjecting it to low-temperature annealing treatment, the spring limit value is significantly improved compared to conventional materials, and it is extremely useful in practice. It is possible to provide high-quality brass for contacts.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between the tensile strength and bending workability of the alloy of the present invention and the known 7/3 yellow steel when the bending line is parallel to the rolling direction, and Figure 2 is a diagram showing the relationship between the tensile strength and bending workability when the bending line is perpendicular to the rolling direction. A diagram showing the relationship between the tensile strength and bending workability of the alloy of the present invention and the known 7/3 brass in the case of the alloy of the present invention and the known 7/3 brass.
3 is a diagram showing the tensile strength and spring limit value after low-temperature annealing of brass. In FIG. 3, curves A and B are the characteristics of the parts perpendicular and parallel to the rolling direction of the alloy of the present invention, respectively, and curves C and D
1 and 2 respectively show the characteristics of parts perpendicular to and parallel to the rolling direction of known 7/3 brass.

Claims (1)

[Claims] IZn25-38wt%, P0.005
~0.100wt% and FeO. 0 0 5
~0. Brass for a contact, characterized in that it contains 100 wt% of copper, with the remainder substantially consisting of Cu. 2. Brass for a contact according to claim 1, which contains 0.010 to 0.030 wt% of P. 3 Fe 0.0 1 5 to 0.0 3 5 wt%
Brass for a contact according to claim 1 or 2, characterized in that it contains: 4 Zn 25-38wt%, PO. 005~0
．． 100wt% and FeO. 0 0 5 ~
A brass ingot containing 0.100 wt% with the remainder substantially consisting of Cu is hot rolled and then cold rolled according to a conventional method, and then annealed at 200 to 300°C for 5 to 180 minutes. Method of manufacturing brass. The method for manufacturing a brass for a contact according to claim 4, characterized in that 5 P is 0.0 10"-0.0 30 wt%. 5 Fe is 0.0 1 5 to 0. .0 3 5 wt
%. The method for manufacturing a brass for a contact according to claim 4 or 5, wherein