JPH06100984A - Spring material excellent in shape freezability and spring limit value and its production - Google Patents

Abstract

PURPOSE:To provide a spring material having superior spring limit value and high Young's modulus and electric conductivity by constituting the composition of a metal sheet of specific weight percentages of Cu, Al, Mn, Ti, Cr, and Mo and the balance Fe. CONSTITUTION:The metal sheet has a composition consisting of, by weight, 20-85% Cu, 0.3-11% Al, 0.05-3.0% Mn, 0.005-3.5% Ti, 0.1-10% Cr, 0.001-1.5% Mo, and the balance Fe with inevitable impurities. The ratio of Cr content to Fe content is regulated to 5.5-13.5%. As alloy components, 0.005-8%, in total, of one or more elements among Zr, Si, Ni, Zn, Sn, Nb, P, La, Ce, Y, V, Ca, Be, Mg, and Hf and 0.005-2%, in total, of C and/or B are further incorporated. By this method, the spring material excellent in manufacturing environment and reliability can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spring material, such as a thin plate (connector or connector), which has an excellent balance between a spring limit value and shape fixability (that is, has a high Young's modulus) and which is excellent in electrical conductivity and reliability. Used for contacts) or wire (used for pins).

[0002]

2. Description of the Related Art As a thin plate material for springs, for example, JI
Cu-1.81Be-0.05Fe of SC1720-P
Alloys, Cu-Ti (2.5 to 5.0% by weight) alloys described in JP-A-1-162736, and the like,
All have excellent spring limit values, but do not combine high Young's modulus and electrical conductivity at the same time.

Further, JIS-1720-P Cu-1.
The 81Be-0.05Fe alloy has a problem of a manufacturing environment and a problem of high cost because Be is added thereto, and a material capable of solving these problems is desired.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a material capable of realizing excellent properties and low cost as a thin plate or wire for springs, and a manufacturing method thereof.

[0005]

In order to achieve the above object, the present invention has the following constitution. That is, the feature of the present invention is, by weight%, Cu: 20 to 85%, A
1: 0.3 to 11%, Mn: 0.05 to 3.0%, T
i: 0.005-3.5%, Cr: 0.1-10%, M
o: An alloy containing 0.001 to 1.5% and the balance being unavoidable impurities and Fe is hot-rolled in a temperature range of 700 to 1000 ° C., and the hot-worked material has a reduction ratio of 50 to 95.
%, Followed by annealing in the temperature range of 450 to 1000 ° C., secondary cold working at a reduction rate of 5 to 85%, further solution treatment followed by rapid cooling, and then 150
By aging treatment in the temperature range of up to 650 ° C., a spring material having an excellent spring limit value and a high Young's modulus and at the same time an excellent electric conductivity can be obtained.

[0006]

[Function] Hereinafter, the reason for limiting the constituent requirements will be described. First,
The reasons for limiting the chemical composition of the alloy are as follows. In order to improve the spring limit value and Young's modulus, the higher the Cu content is, the more preferable it is. However, in order to meet the electric conductivity requirement of the contact spring thin plate, the Cu content should be controlled to achieve the desired electric conductivity. It is desirable to obtain a balance between the spring limit value and Young's modulus. If the Cu content is less than 20% by weight as shown in FIG. 1, the electrical conductivity required for a thin plate or wire for spring cannot be obtained and only the effect on the spring limit value and Young's modulus can be obtained, so this is the lower limit. Further, the upper limit is set to 85% by weight, when the total content of Fe and other than Cu is less than 15% by weight, a balance between the high Young's modulus characteristic of the present alloy and an excellent spring limit value is obtained. Because it will disappear. Therefore, Cu is 20
To 85% by weight.

Next, the content of Al in the range of 0.3 to 11.0% by weight is that if it is less than 0.3%, the effect on improving the hot workability is small, and if it exceeds 11.0% by weight, the hot workability is improved. This is because the effect of is saturated and the decrease in conductivity becomes large. Furthermore, Mn improves the hot workability by the combined effect of Al and
If it is less than 0.05% by weight, the effect is small, and if it exceeds 3% by weight, the effect is saturated. Therefore, it is specified in the range of 0.05 to 3% by weight. Further, the Ti content is specified to 0.005 to 3.5% by weight when less than 0.005%, the effect on conductivity is small,
This is because if it exceeds 3.5% by weight, the effect on conductivity is saturated and the productivity such as casting and cold working is impaired.

Cr in 0.1 to 10% by weight, and Mo
Is defined as 0.001 to 1.5% by weight, respectively, in order to improve the crevice corrosion resistance as a thin plate for spring or wire material by the combined effect of Cr and Mo without deteriorating the solder / Ag plating property, If the Mo content is less than 0.001% by weight, the effect on crevice corrosion is small, and if it exceeds 1.5% by weight, the effect on crevice corrosion is saturated and the cost increases. The Cr content is 5.5 to 1 by weight ratio with respect to the Fe content.
When it is defined to be 3.5%, the corrosion resistance of the material can be further improved by the combined effect with Mo. That is, if it is less than 5.5%, the effect is insufficient, and 13.5.
%, The effect on corrosion resistance is saturated and solder / Ag
It is in this range because it deteriorates the plating property.

Further, it is necessary to improve casting structure control, spring limit value / strength enhancement, workability, various plating properties, and solder weather resistance (peeling property at 150 ° C. for 1000 hours or more after soldering). In addition, Zr, Si,
Ni, Zn, Sn, Nb, P, La, Ce, Y, V, C
One or more of a, Be, Mg and Hf are added in a total amount of 0.005 to 8% by weight, and one or two of C and B are added in a total amount of 0.005 to 2% by weight.

Particularly, in the case of a component in which the weight ratio of the Cr content to the Fe content exceeds 6% and the Mo content thereof exceeds 0.01%, the above-mentioned respective components are added within the range of 0.005% by weight or more, It is possible to obtain a metallic structure in which the Fe phase containing Cr and Mo and the Cu phase of the present invention are uniformly finely dispersed,
This is important for obtaining a metal structure having crystal grains of 10 μm or less in the plate thickness direction after processing and heat treatment.

Next, a method for manufacturing the spring material of the present invention will be described. After ingoting the molten metal having the above-mentioned chemical components into an ingot or slab, it is hot worked into a material having a desired plate thickness or diameter in a temperature range of 700 to 1000 ° C., and subsequently, a rolling reduction of 50 to 95%. Primary cold working is performed. This is to obtain the plate thickness or diameter required for the thin plate for spring or wire rod, and to perform the rolling by 50% or more to impart the workability by the subsequent annealing treatment. The above-mentioned annealing method is intended only to release the processing strain accumulated in the primary cold working, with emphasis on the strength of the material, and the steps of gradual heating, holding at a relatively low temperature, and gradual cooling are performed in order. Such treatment conditions are heating rate of 0.05 to 5000 ° C./min, 450 to 10
A holding temperature of 00 ° C. and a cooling rate of 0.05 to 5000 ° C./min are suitable.

Further, recrystallization may be caused by the processing strain accumulated in the primary cold working to obtain a material having small anisotropy. In any case, after that, it is necessary to perform secondary cold working at 5 to 85%, perform solution treatment in the temperature range of 700 to 1000 ° C., perform rapid cooling, and then perform aging treatment. If the reduction ratio of the secondary cold working is less than 5%, the dislocation density required for aging precipitation is insufficient, and if it exceeds 85%, the workability deteriorates. Therefore, the reduction ratio of the secondary cold working is specified in the above range. The annealing condition is 450 to 10
After retaining in the temperature range of 00 ° C, when cooling at a cooling rate of 0.05 to less than 0.5 ° C / min, or after retaining in the temperature range of 450 to less than 700 ° C, 0.5 to 5000 ° C / min. When cooling, the solution treatment shown below is performed if necessary.
That is, after retention in the temperature range of 700 to 1000 ° C.
The solution treatment can be omitted when annealing is performed in which the material is rapidly cooled at a cooling rate of 5 to 5000 ° C./min. The solution treatment and the quenching are performed in order to dissolve the components of the cold rolled material into a supersaturated solid solution and more effectively perform the aging treatment.
Hold for 10 seconds to 2 hours in the temperature range of ˜1000 ° C. is preferable. The quenching uses a cooling medium of water or an inert gas, and a cooling rate of 0.5 to 5,000 ° C./min is suitable.

Aging treatment is indispensable in the manufacturing process in order to improve the spring limit value and electric conductivity, and an appropriate temperature should be selected depending on the chemical composition and the conditions of the previous process. As the condition, due to the relationship between the spring limit value and the conductivity, strain will occur around the precipitates if the temperature is too low and the conductivity and elongation will decrease, and equipment restrictions and manufacturing to obtain the desired conductivity will occur. Efficiency is affected and costs are increased. On the other hand, if the temperature is too high, the amount of precipitation will decrease and a high spring limit value cannot be obtained. Therefore, the optimum condition for aging treatment is 250 to 650 ° C.
That is, the aging treatment is performed for 10 to 500 minutes in the temperature range.

The thin metal plate is processed into a coil shape or a slit shape and then plated with Ni, Cu, Ag, Au or the like, or alloy plating thereof, solder, Sn plating and the like. Alternatively, the metal plate is processed as a spring component in advance, and then the plating process is performed. In either case, plating is performed under the following conditions. Plating is performed by electrolytic or immersion degreasing on such a base plate using an alkaline degreasing agent,
Further, after the surface is activated by pickling, electric or immersion plating is performed using a desired metal bath or alloy bath. The above metal wire is also subjected to the same plating treatment.

The thickness of the plating layer is usually 0.01 to 10 μm.
The range is about 0.2 to 5.0 μm in terms of adhesion, thickness uniformity, solder weather resistance and economy. When the thickness is 0.20 μm or less, the solder weather resistance (a phenomenon in which the solder is peeled off by heating at 150 ° C. for 1000 hours or 1500 hours at low temperature for a long time) and the presence of pinholes deteriorate reliability. On the other hand, if it exceeds 5.0 μm, the adhesion and the uniformity of thickness are deteriorated.

[0016]

【Example】

Example 1 Alloys in the composition range of the present invention shown in Tables 1 and 2 (Sample materials A to F)
And S-II) and alloys in the composition range of the comparative example (test materials G-R)
Each was vacuum-melted with a high-frequency induction heating device, and a slab was manufactured by continuous casting, followed by hot rolling at 950 ° C. to obtain a metal plate having a plate thickness of 1.8 mm.

[0017]

[Table 1]

[Table 2]

Next, the hot-rolled sheet was subjected to a primary cold rolling of 85%, subsequently heated to 950 ° C. at a heating rate of 1000 ° C./min, held at this temperature for 60 minutes, and then heated with nitrogen gas for 15 minutes.
Annealing was performed to cool at a cooling rate of 00 ° C / min. Then, 25% secondary cold rolling was performed, and then aging treatment was performed at 480 ° C. for 3 hours. Further, the alloys of the test materials B and C were subjected to the same primary cold rolling as described above, and the annealing condition was set to 1000
Heating rate up to 650 ° C at 60 ° C / min and 60 at this temperature
After holding for 2 seconds, cooling with nitrogen gas was performed at a cooling rate of 100 ° C./min. Then, after performing 25% secondary cold rolling,
Solution treatment of holding for 2 minutes at 0 ° C, then 1500
Nitrogen gas was cooled at a cooling rate of ℃ / min, and continued to 480
An aging treatment was performed at 3 ° C. for 3 hours. The material properties of the obtained metal thin plates are shown in sample numbers 1 to 35 in Tables 3 and 4. Further, as a comparative example, an alloy such as Be-Cu, Cu-Ti, phosphor bronze or CDA195 was used and its characteristics were added. The alloys I and K could not be evaluated because of hot rolling cracks.

The spring limit values in Tables 3 and 4 are measured by the moment method, the strength is measured by the JIS13B tensile test (pulling speed: 10 mm / min), the Young's modulus is measured by the resonance method, and the conductivity is measured by the four-terminal method. I asked. As corrosion resistance, crevice corrosion is 0.125 mm including cut surface, plate thickness is 10 mm
A sample with a width of 30 mm is sandwiched between polycarbonate resins and a salt spray test is performed for 96 hours according to JIS-Z2371, and the area of red rust on the entire surface of the sample is judged to be the same. I went with the material naked.

Regarding solder wettability in terms of plating property, a wetted area rate of 95% or more was passed. The heat resistance of Ag plating is about 0.3 μm after Cu strike plating.
Was plated for about 3 μm, and then heated in air at 430 ° C. for 3 minutes, and judged by occurrence of swelling on the plated surface. Manufacturability includes nozzle clogging during casting and cold workability (2.0 mm
From 0.1 to 0.125 mm without intermediate annealing, when cold working within 15 baths, cracks at the edge and center)
It was judged by. Furthermore, the cost evaluation was judged to be good when 1.3 times or less of the average raw material price when Mo was not added.

Here, Sample No. 7 is the case where the added amount of Cu is 20% by weight or less, and the conductivity is as low as phosphor bronze. Sample No. 8 has a low Young's modulus because the amount of addition of elements such as Fe that effectively acts on Young's modulus is small when the amount of Cu added is 85% by weight or more.
Since the amount of Mn added is large, the conductivity is low. Sample number 1
Nos. 2 and 14 have a large amount of Ti and Mo added, and thus the cost is high.
Sample No. 11 has a Ti content of 0.005% or less and thus has low conductivity, and Sample No. 12 has a Ti content of 3.5% or more and is inferior in productivity. Sample No. 13 has a low Mo content because of low Mo, and Sample No. 14 has a high cost. Further, since the sample number 15 has low Cr, the corrosion resistance is low, and the sample number 16 is inferior in solder wettability and heat resistance of Ag plating. Thus, it is clear that the characteristics of the present invention are superior to those of the comparative example.

[0022]

[Table 3]

[Table 4]

Example 2 Alloys and test materials B and S in the composition range of the present invention shown in Tables 1 and 2
Melting and continuous casting were carried out in the same manner as above and hot rolling was performed to obtain a metal plate having a plate thickness of 2.0 mm. This metal plate was subjected to surface grinding after considering the reduction ratio so that the plate thickness after the primary cold rolling would be 0.15 mm, and then the primary cold rolling was performed with a reduction ratio of 35,
Performed at three levels of 55 and 85%. Thereafter, these metal plates were annealed at 950 ° C. for 60 seconds, and after the treatment, they were rapidly cooled with nitrogen gas at 100 ° C./min. Subsequently, secondary cold rolling was carried out at 5 levels of 3, 8, 25, 65 and 90% to obtain metal thin plates having plate thicknesses of 0.146, 0.138, 0.120, 0.068 and 0.053 mm. Then add 5 to each sheet of metal.
Aging treatment was performed at 50 ° C. for 3 hours.

The material characteristics of the above metal plate are shown in Tables 5, 6, 7 and 8. The evaluation was carried out by measuring the spring limit value / strength and the electric conductivity in the same manner as in Example 1, and the workability was based on contact bending. From the results below, those with a low primary cold rolling rate and those with a secondary cold rolling rate of more than 90% have poor workability, and those with a secondary cold rolling rate of less than 5% have electrical conductivity. Turned out to be low.

[0025]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

[0026]

As described above, the present invention replaces Be-Cu alloys, Cu-Ti alloys and phosphor bronze currently used as spring materials with excellent spring limit values, high Young's modulus and excellent conductivity. In addition to providing the spring material having good reliability and manufacturing environment, its industrial effect is remarkable.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a Cu content (%) in an Fe phase, a spring limit value, a Young's modulus, and conductivity.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhide Ohno 1618 Ida, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Nippon Steel Corporation Advanced Technology Research Laboratories

Claims (10)

[Claims] 1. By weight%, Cu: 20-85%, Al:
0.3-11%, Mn: 0.05-3.0%, Ti:
0.005-3.5%, Cr: 0.1-10%, Mo:
A spring material having an excellent spring limit value and shape fixability, characterized by containing 0.001 to 1.5% and the balance being a thin metal plate composed of unavoidable impurities and Fe. 2. The spring material according to claim 1, wherein the ratio of the Cr content to the Fe content is 5.5 to 13.5%. 3. Zr, Si, N as an alloy component
i, Zn, Sn, Nb, P, La, Ce, Y, V, C
A total of 0.005 to 8% by weight of one or two or more of a, Be, Mg and Hf, and a total of 0.005 to 2% by weight of one or two of C and B. Material for spring. 4. Ni, Cu, A on the surface of the thin metal plate
The spring material according to claim 1, 2 or 3, wherein metal plating of g or Au or an alloy thereof, solder or Sn plating is applied in a single layer or a multilayer of 0.01 to 10 µm. 5. An effective amount of the alloy according to claim 1, 2 or 3 is melted and agglomerated, followed by hot working in a temperature range of 700 to 1000 ° C., and the hot working material is rolled to a rolling reduction of 50 to 95. % Primary cold work, then hold in the temperature range of 450 to 1000 ° C., and then perform rapid annealing at a cooling rate of 0.05 to 5000 ° C./min. Processed,
Subsequently, a method for producing a spring material having an excellent spring limit value and shape fixability, which is characterized by performing an aging treatment in a temperature range of 150 to 650 ° C. 6. Hot working, primary cold working and then 450
After holding in the temperature range of 1000 ° C to 1000 ° C, 0.05 to 0.
Annealing is performed at a cooling rate of 5 ° C / min, secondary cold working is performed, and solution treatment is performed in a temperature range of 700 to 1000 ° C, followed by cooling at a cooling rate of 0.5 to 500 ° C / min, and further aging. The manufacturing method according to claim 5, wherein treatment is performed. 7. Hot working, primary cold working followed by 450
After holding in the temperature range of ~ 700 ° C, over 0.5 ~ 500
Annealing is performed at a cooling rate of 0 ° C / min, secondary cold working is performed, and solution treatment is performed in a temperature range of 700 to 1000 ° C, followed by cooling at a cooling rate of 0.5 to 500 ° C, and further aging treatment. The manufacturing method according to claim 5, which is performed. 8. The production method according to claim 5, 6 or 7, wherein the weight ratio of the Cr content to the Fe content is 5.5 to 13.5%. 9. An alloy component further comprising Zr, Si, N
i, Zn, Sn, Nb, P, La, Ce, Y, V, C
6. A total of 0.005 to 8% by weight of one or more of a, Be, Mg and Hf, and 0.005 to 2% by weight of one or two of C and B. The manufacturing method according to 6 or 7. 10. After the aging treatment, the surface of the processed material is plated with metal such as Ni, Cu, Ag, or Au or their alloys, solder or Sn plating to a thickness of 0.01 to 10 μm.
The method according to claim 5, 6, 7, 8 or 9, wherein the production is performed in a single layer or a multi-layer of m.