JP2000319737A - Brass sheet material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the machinability and grindability of the subject sheet material by increasing the area ratio of crystal phases other than an α phase after rolling. SOLUTION: In this brass material, by executing heating at 550 to 800 deg.C in the case of a compsn. in which the apparent content of Zn is 33.5 to 43 wt.% and executing heating in the temp. range of 550 to 800 deg.C or 400 to 500 deg.C in the case of a compsn. in which the apparent content of Zn is 38.5 to 43 wt.%, the area ratio of a βphase is increased, and, preferably, the area ratio can be controlled to >=5%. Then, for preventing the reduction of the once increased β phase in the process of cooling, rapid cooling is executed in such a manner that the cooling rate to 400 deg.C is controlled to >=5 deg.C/sec in the case the heating temp. range is 550 to 800 deg.C and the cooling rate to 400 deg.C is controlled to >=1 deg.C/sec in the case the heating temp. range is 400 to 500 deg.C. Moreover, cold working such as bending and press working is suitably executed before the heating treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a brass material and a method for producing the same, and more particularly to a brass sheet material and a method for producing the same.

[0002]

2. Description of the Related Art Heretofore, brass plate materials have generally been of an α-phase. This was a result of reducing the ratio of the β phase that inhibits cold ductility in preparation for cold rolling or cold bending / pressing.

[0003] However, since a single-phase brass plate material of α-phase does not utilize a β-phase having excellent machinability and abrasiveness, there is a problem that the machinability and abrasiveness are inferior.

[0004] In addition, the conventional brass sheet material has a problem that the corrosion resistance and strength are inferior because the crystal grain size is similarly increased to ensure cold ductility.

[0005] An object of the present invention is to improve the machinability and abrasiveness of a brass material produced through cold working, particularly a brass plate material.

[0006]

In the method for producing a brass material according to the present invention, after rolling, the area ratio of the crystal phase other than the α phase is increased, so that the machinability is improved.
A brass material excellent in abrasiveness can be provided.

In a preferred embodiment, the apparent Zn
In the case of a composition having a content of 33.5 to 43 wt%, 550
When the apparent Zn content is 38.5 to 43 wt% by heating to 550 to 800 ° C.
Or by heating to a temperature range of 400 to 500 ° C,
The area ratio of the β phase can be increased, and preferably, the area ratio of the β phase can be 5% or more.

Here, the term "apparent Zn content" means that A is a Cu content [wt%], B is a Zn content [wt%], and t is a third element (for example, Sn). Z
Assuming that n equivalents and Q are the content of the third element [wt%], “{(B + t · Q) / (A + B + t · Q)} × 10
0 ”is used.

In order to prevent the increased β phase from decreasing during cooling, when the heating temperature range is 550 to 800 ° C., the cooling rate up to 400 ° C. is 5 ° C./sec or more, and the heating temperature range is 400 ° C. In the case of up to 500 ° C., rapid cooling may be performed so that the cooling rate to 400 ° C. is 1 ° C./sec or more.

In another preferred embodiment, the apparent Zn content is 33.5 to 43 wt%, and the Sn content is 0.1 to 0.3 wt%.
When the content is 5 to 2.0 wt%, the area ratio of the γ phase can be increased by heating to a temperature range of 400 to 500 ° C., and preferably the area ratio of the γ phase can be 1% or more.

Here, if the temperature range of 400 to 500 ° C. is maintained for one hour or more, the γ phase becomes spherical, and the strength, machinability and polishing properties are further improved. In order that the increased γ phase does not decrease during cooling, the cooling rate up to 400 ° C.
It is preferable to quench rapidly so that the temperature is at least ° C / sec.

The apparent Zn content is 33.5-4.
In the case of a composition having a Sn content of 3 wt% and a Sn content of 0.5 to 1.3 wt%, cold working is easy because the Sn content is relatively small, and an apparent Zn content is 33.5 to 43 wt%. S
In the case of a composition having an n content of 1.3 to 2.0 wt%, the γ phase can be easily precipitated because the Sn content is relatively large.

As a preferred embodiment of the present invention described above, cold working such as bending or pressing can be performed before the heat treatment step.

In this case, it is preferable to provide a pregelatinizing heat treatment step for increasing the area ratio of the α phase before the cold working to ensure the cold ductility in advance. In this pregelatinization heat treatment step, for example, the apparent Zn content is 33.5 to 43 wt.
In the case of%, the temperature is maintained at 450 to 550 ° C. for 10 minutes or more. If the crystal grain size is increased during the pregelatinization heat treatment step, the ductility during cold working can be improved.

[0015] By such a pre-gelatinization heat treatment step, the area ratio of the α phase is at least 90%, preferably at least 95%, or the elongation at cold is at least 20%, preferably at least before cold working. It can be 35% or more.

After the cold working, an annealing step for tempering the internal stress is usually performed. This annealing step may be performed before or after the heat treatment step.

Further, in the method for producing a brass material according to the present invention, the average grain size is reduced to 50 μm or less, preferably 25 μm by performing the grain size reduction treatment during or before the heat treatment step. In the following manner, it is possible to reduce surface roughness during bending and press working while further improving the abrasiveness.

It is desirable that the grain size reduction treatment is performed after cold working. In other words, before cold working, the crystal grain size is large to ensure cold ductility, but if the crystal grain size remains large after cold working,
Abrasion, corrosion resistance and strength are inferior. Therefore, the crystal grain size is reduced through the crystal grain size reduction step after the cold working, so that the polishing property and the like are improved.

In a preferred embodiment, the grain size reduction treatment can be performed by recrystallizing the dislocations introduced by cold working by heating. In this case, it is desirable to increase the dislocation density as much as possible during cold working, and it is preferable that the cross-sectional reduction rate is 20% or more.

In order to prevent the crystal grain size from becoming coarse again,
It is desirable to set an upper limit on the heating time or to rapidly cool after heating. For example, in the case of the heat treatment step of heating to 550 to 800 ° C., by setting the upper limit of the heating maintenance time to 30 minutes or less, it is possible to prevent the crystal grain size from re-coarsening.

As a preferred embodiment of the cold working in the present invention described above, when cold working and annealing are repeatedly performed, the cross-sectional reduction rate of the last cold working is increased, and the final cold working is performed more than the intermediate annealing. It is desirable to lower the annealing temperature.
For example, when the intermediate annealing temperature is 500 to 600 ° C.,
The final annealing temperature is desirably 500 ° C. or less.

Further, as a use of the method for producing a brass material according to the present invention, it is desirable to apply the method to a method for producing a brass tube. This is because the plate material is often subjected to press working and bending work.

Subsequently, the brass material according to the present invention has (1) a cutting resistance index of 50 or more, preferably 80 or more, based on a free-cutting brass bar according to Japanese Industrial Standard JIS C-3604; In the case where Sn is contained as a raw material composition, when a dezincification corrosion test according to the Japan Copper and Brass Association Technical Standard JBMA T-303 is performed, the maximum dezincification depth is determined when the maximum dezincification penetration depth direction is parallel to the processing direction. 100μ
m or less, or when the maximum dezincing penetration depth direction is perpendicular to the processing direction, the maximum dezincing depth is 70 μm or less.

A preferred embodiment of such a brass material is a plate material. In addition to a plate material obtained by roll bending or rolling from a plate material to a shape represented by an “L-shape” or “U-shape”, a plate material may be used. The present invention is also applicable to a joined product formed by bending and pressing and then joining the ends thereof.

When this manufacturing method is used, in addition to the characteristics described here, excellent characteristics can be exhibited in terms of abrasiveness. That is, regarding the abrasiveness, 1. When the polishing is performed under the same conditions, the surface roughness after polishing is smaller than that of the conventional material. 2. When the polishing is performed under the same conditions, the polishing amount is larger than that of the conventional material. When polished under the same conditions, it is evaluated from the viewpoint that there is no defect in the appearance compared with the conventional material and that the plating paste is good,
This is because the results of evaluation from these viewpoints show that the brass plate according to the present invention is superior to the conventional brass tube.

If this polishing property is quantified, the plate material according to the present invention, after the heat treatment step, has a polishing apparatus with a burler ECOMMET IV and a polishing disk rotation speed of 200 rpm.
m, sample pressing pressure is 6.9 KPa, polishing paper is SiC #
When the surface of # 80 flaw is polished under the condition of 600, the polishing is completed in half the time as compared with a brass plate material according to Japanese Industrial Standard JIS C-2700.

In the tube according to the present invention, after the heat treatment step, the polishing apparatus has a burler ECOMMET IV, the rotation speed of the polishing machine is 150 rpm, and the sample pressing pressure is 6.9 KP.
a, When the surface of a flaw of # 600 is polished under the condition that the polishing powder is Al2O3, the polishing is completed in half the time as compared with a brass plate material according to Japanese Industrial Standard JIS C-2700.

In addition, the sheet material according to the present invention has Sn as a raw material composition and has been subjected to bending, and the bent portion is subjected to a heat treatment process, and is subjected to a heat treatment process. When a dezincification corrosion test according to −303 is performed, the maximum dezincification depth is 70 μm or less.

Subsequently, the brass material produced through the cold working according to the present invention has a first phase composed of an α phase, a second phase different from the first phase, and an area ratio of the first phase. Is 99% or less, so that the cutting property and the polishing property are improved as compared with the brass material manufactured through the conventional cold working of α single phase.

In a preferred embodiment, by setting the area ratio of the β phase to 5% or more, the β phase which is originally excellent in cutting properties and abrasiveness is effectively used to secure cutting properties and the like. Further, by setting the area ratio of the β phase to 40% or less, preferably 20% or less, corrosion resistance can be ensured.

More preferably, the Sn concentration in the β phase is set to 1.
When the content is 5 wt% or more, the β phase which is originally poor in corrosion resistance can be strengthened, and the corrosion resistance can be improved as a whole.

By setting the average crystal grain size to 50 μm or less, preferably 25 μm or less, it is possible to suppress not only the surface roughness of the bent portion and to improve the abrasiveness but also the corrosion resistance and strength.

In another preferred embodiment, by setting the area ratio of the γ phase to 1% or more, the cutting property and the abrasive property at the interface between the hard γ phase and the other phase are effectively utilized for cutting. The strength is to be improved by utilizing the strength of the γ phase while ensuring the properties and the like. Preferably, the area ratio of the γ phase is 30%.
% Or less, the brittleness of the γ phase is reduced.

More preferably, if the average crystal grain size (minor diameter) of the γ phase is 8 μm or less, preferably 5 μm or less,
The brittleness of the γ phase can be further reduced.
If the concentration is 8% by weight or more, the corrosion resistance is improved. In particular,
When the β phase is contained, the Sn concentration is 8 wt% or more.
By surrounding the β phase with the phase, the β phase originally having poor corrosion resistance can be protected, and the corrosion resistance can be improved as a whole.

The brass sheet according to the present invention (including a sheet not subjected to cold rolling) comprises: (1) an area ratio of a γ phase of 1% or more; (2) a first phase composed of an α phase; A second phase different from the first phase, and the area ratio of the first phase is 9
(3) a first phase consisting of an α phase, wherein the second phase has an average crystal grain size (minor axis) of 8 μm or less, and a second phase different from the first phase; The area ratio of the first phase is 95% or less, and the average crystal grain size is 50 μm.
m, preferably 25 μm or less. (4) Average crystal grain size is 25 μm or less, α phase is 25 μm or less, β
The phase has a characteristic of 20 μm or less, and the γ phase has a characteristic of 8 μm or less.

The brass sheet material according to the present invention also has (1) a cutting resistance index of 50 or more, preferably 80 or more based on a free-cutting brass bar according to Japanese Industrial Standard JIS C-3604, and (2) a polishing apparatus using a burler ECOMMET. IV,
Polishing machine rotation speed 200 rpm, sample pressing pressure 6.9
When KPa and abrasive paper are surface-polished with scratches of # 80 under the condition of SiC # 600, Japanese Industrial Standard JIS C-270
Polishing is completed in half the time as compared with the brass plate material according to No. 0. (3) The polishing apparatus is a burler ECOMMET I
V, when the surface of a scratch of # 600 was polished under the conditions of a polishing disk rotation speed of 150 rpm, a sample pressing pressure of 6.9 KPa, and an abrasive powder of Al2O3, Japanese Industrial Standard JIS C-2
Compared to a brass sheet material according to No. 700, polishing is completed in half the time.

Subsequently, the brass sheet according to the present invention has an apparent Zn content of 33.5 to 43.0 wt% and an Sn content of 0.5 to 1.3 wt%, or an apparent Zn content of 0.5 to 1.3 wt%. It is characterized in that the content is 33.5 to 43.0 wt% and the Sn content is 1.3 to 2 wt%. As another component, the Pb content is preferably 0.07% by weight or less because if it is too large, the cold ductility decreases.

That is, if the apparent Zn content is too large, it is difficult to increase the α phase ratio during cold working,
And during ge-annealing, the γ phase that inhibits cold ductility tends to precipitate, and if it is too small, it is difficult to increase the ratio of β and γ phases after cold working. In addition, it is possible to secure the machinability and the abrasion after cold working while maintaining the cold ductility during cold working.

In the former, the cold working is easy because the amount of Sn is relatively small, and in the latter, the β and γ phases can be easily precipitated because the amount of Sn is relatively large.

The brass sheet according to the present invention described above has a higher apparent Zn content than the conventional brass sheet, so that the ratio of the soft β phase is high and the hot rolling resistance is low during hot extrusion. Excellent rollability.

That is, if the rolling is performed in the same temperature range as that of the conventional brass sheet material, it is possible to perform the rolling at a reduction rate of the cross section higher than the conventional one, and by performing hot rolling to a thickness close to the final sheet thickness, The load of cold rolling can be reduced.

On the other hand, if hot rolling is performed at the same area reduction ratio as in the past, rolling at a lower temperature than in the prior art is possible.
The billet heating load can be reduced.

Here, it is desirable to cool as quickly as possible after hot rolling. That is, due to the addition of Sn, if the cooling rate after rolling is low, a large amount of γ phase precipitates, and a long time is required for the post-gelatinization heat treatment step. Suppress, α + β organization is α
The time for the chemical heat treatment step can be reduced.

[0044]

Embodiments of the present invention will be described in detail below. FIG. 1 shows a conventional manufacturing process of a brass sheet material [conventional example].
(A) and the manufacturing process [example] (b) and (c) of the brass plate material of the embodiment of the present invention are shown.

In the conventional example (a), first, after the brass raw material is melted (step 1), continuous casting is performed (step 2) to form a billet (step 3).

After heating to the recrystallization temperature range (step 4), hot rolling is performed to adjust the crystal arrangement and remove the brittleness of the cast structure (step 5) to form a blank (step 6). ).

Subsequently, cold rolling is performed to a predetermined thickness (Step 7), and after correcting the plate shape (Step 8), annealing is performed for removing internal stress or tempering (Step 9). , Cutting, etc. to make a plate product (Step 1
0). In an actual manufacturing process, steps 7 to 9 are often repeated.

After such a plate product is subjected to bending, pressing and the like (step 11), it is cut and polished (step 12) to become a final product.

In the above manufacturing process, the blank in step 6 is required to have cold ductility as a sheet material during the cold rolling in step 7, so that α has the best cold ductility in the crystal phase.
It was a single phase.

At the same time, in step 1, a brass material having a small apparent Zn equivalent is used in steps 6 and 7 so as to easily become an α single phase, and in step 12, cutting and polishing are performed with the α single phase unchanged. Therefore, there was a problem that the cutting and polishing properties were inferior. (Because the α phase has poor cutting and polishing properties among the crystal phases)

Next, the embodiment (b) will be described.
First, in Step 1, a raw material having an apparent Zn equivalent higher than that in the related art is dissolved to make it easier to generate a β phase. (The apparent Zn content is preferably 33.5 to 43.0 wt%.)

The following steps 2 to 6 follow the same steps as the conventional example, but since the Zn equivalent was increased in step 1,
The raw plate in step 6 is in the α + β mixed phase. Here, when proceeding to cold rolling in the same manner as in the conventional example, the cold-ductility is inferior to the conventional example, so the cross-sectional reduction rate during rolling cannot be increased, and the number of rolling steps increases. Occurs.

Therefore, in the embodiment (b), as step 7, a pre-gelatinizing annealing process for converting the α + β mixed phase into a substantially α-single phase is performed. Fig. 4 About pregelatinized annealing
More specifically, a process of heating to 550 ° C. for 15 minutes, maintaining the temperature at 550 ° C. for 20 minutes, and cooling to room temperature for 15 minutes is performed. The heating time of this pregelatinizing annealing treatment is appropriately changed depending on the composition and the heating temperature. FIG. 5 shows a modified example thereof.

Here, if the crystal grain size has been reduced by the hot extrusion in step 5, it is desirable to increase the crystal grain size during pregelatinizing annealing. Because, in order to increase the cold ductility in the cold working in Step 8,
This is because increasing the crystal grain size in addition to increasing the area ratio of the α phase contributes.

In the example of FIG. 4, the average crystal grain size is 15 μm.
As a result of performing the treatment shown in FIG. 2 on the α + β mixed-phase pipe having a diameter of not more than m, an α-single-phase pipe material having an average crystal grain size of more than 30 μm was obtained. The grain size has also been increased. It should be noted that the increase in the α-phase area ratio and the increase in the average crystal grain size are as shown in FIG.
It may be performed in separate steps instead of in one step.

Returning to FIG. 1B, after such a step 7, steps 8 to 12 similar to those of the conventional example are performed, but at the time of cold rolling at step 8 and at the time of bending / pressing at step 12. Is performed in α single phase as in the conventional case, so that the same cold workability as in the conventional example can be obtained. Step 7,
When Step 8 is repeated, the working ratio at the time of the last cold rolling is preferably as large as possible.

Thereafter, in the conventional example, cutting in step 12
Although the process proceeds to the polishing process, in the embodiment (b), a β annealing treatment for converting the α single phase into an α + β mixed phase is inserted before that (step 13). And this step 1
By proceeding to the cutting and polishing in step 14 after passing through 3, the cutting and polishing properties inherent in the β phase can be effectively used.

Here, the β-annealing treatment will be described in detail with reference to FIGS. 6 to 9. First, in FIG.
After heating to ℃, the temperature is maintained at 650 ° C for 30 seconds, and then a process of rapidly cooling to room temperature is performed.

The heating time of the β-annealing treatment is preferably within 30 minutes. This is because maintaining the high temperature state for a long time causes the crystal grain size to increase. The heating time of the beta annealing treatment is appropriately changed depending on the composition and the heating temperature. FIG. 7 shows a modified example thereof.

Next, in FIG. 8, after heating to 450 ° C. for 1 minute, 450 ° C. is maintained for 2 minutes, and cooling to room temperature is performed for 1 minute. Since the heating temperature in this example of β-annealing is lower than that in the examples of FIGS. 6 and 7, the crystal grain size does not become coarse even if it is maintained for a long time. The heating time of the β-annealing treatment for preventing such crystal grain coarsening is also appropriately changed depending on the composition and the heating temperature. FIG. 9 shows a modified example thereof.

Further, in any of FIGS. 6 to 9, it is desirable to rapidly cool in a cooling process after heating. This is because, if the cooling is performed slowly, the area ratio of the β phase having a desired area ratio may change in the process, or the crystal grain size may be increased. Specifically, in FIGS. 6 and 7, the cooling rate to 400 ° C. is set to 5 ° C./sec or more, and in FIGS. 8 and 9, the cooling rate to 400 ° C. is 1 ° C.
/ Sec or more.

Returning to FIG. 1, the embodiment (c) will be described following the embodiment (b).
The only difference is that the annealing treatment of step 10 and the β-annealing treatment of step 13 are also used, and the β-annealing treatment of step 10 is different. The rest is the same as the embodiment (b).

When the two kinds of annealing processes are used in this way, not only the number of steps can be reduced, but also the following advantages can be obtained. In other words, while a large and long plate material is targeted before step 11, step 11
In the following, the target is a small and short plate after cutting a large and long plate, and there is a problem that it is difficult to design equipment for annealing as compared with a large and long plate. Therefore, the embodiment (c)
Such a problem can be solved by performing the beta annealing treatment at the stage of a large and long plate material as described above.

In the embodiment (c), there is a concern that the workability may decrease due to the α + β mixed phase during the bending in step 12 which is the cold working. In comparison, since the bending may be performed at the same level of cold ductility, care should be taken so that the β-phase area ratio does not become too large.

In the embodiments (b) and (c) described above,
During the process, an average crystal grain size reduction process is also performed. This is because, in order to improve the abrasion, it is important to reduce the crystal grain size in addition to increasing the β phase area ratio. More specifically, the last cold drawing in step 7 is performed with a large working degree, and the recrystallization is performed during the annealing in step 10 in the embodiment (b) and during the β-annealing in step 10 in the embodiment (c). That is, the crystal grain size is refined.

In the above embodiments (b) and (c), the β-annealing treatment for increasing the β-phase area ratio was included, but as a modification, the γ-phase area ratio was changed to the β-annealing treatment. It is also useful to use a gamma annealing treatment to increase the amount. That is, since the γ phase is inferior in cold ductility but hard, it has the property of improving the cutting and polishing properties due to the difference in hardness between crystals at the interface with the α and β phases.

The embodiment relating to the gamma annealing treatment is as shown in FIG. 2. In the embodiments (b) and (c), the gamma annealing is replaced with the gamma annealing in the embodiment (d). (E).

The gamma annealing treatment will be described in detail with reference to FIG. 10. In FIG. 10, after heating to 420 ° C. over 30 minutes, maintaining the temperature at 420 ° C. for 60 minutes, and then cooling to room temperature. . In the example shown in FIG. 10, since the heating temperature is low, the crystal grain size does not increase even if the heating temperature is maintained for a long time or the cooling rate is slow.

Here, in the embodiment (e), the base plate of step 6 is subjected to the cold rolling of step 8 after the pre-gelatinizing annealing of step 7; If the area ratio of the α phase can be secured, it is not always necessary to perform the α annealing before the cold rolling.

This is shown in the embodiment (f) of FIG. In Example (f), since the alpha annealing before cold rolling is omitted, the number of steps can be reduced. Note that α
Needless to say, the reduction of the annealing can be applied not only to the case of performing the gamma annealing as in the embodiment (f) but also to the case of performing the β annealing.

Subsequently, the embodiments (b) to (d) described so far.
(F) is to form into a plate shape at the time of the hot rolling in step 5, but the scope to which the present invention is applied is not limited to this.

An embodiment different from the embodiments (b) to (f) is shown in an embodiment (g) in FIG. 3, which shows a method for manufacturing a so-called shaped member. Even in the case of the embodiment (g), the same characteristics as those of the embodiments (b) to (f) can be provided by including gamma annealing (may be β annealing) in the step 12.

Further, the above-described embodiments (b) to (d)
The main aim was to ensure both the cold ductility during cold working and the cutting and polishing during polishing, and to ensure the abrasiveness. Therefore, corrosion resistance can be ensured after the miniaturization treatment.

When the corrosion resistance is taken as a new point of view, the following embodiment can be adopted. That is, in Examples (b) to (d), there is a concern that corrosion resistance is inferior because the β and γ phases are precipitated, but it has been found that this can be solved by including an appropriate amount of Sn in the β and γ phases. are doing.

Accordingly, in Examples (b) to (d), Sn was contained at the time of dissolving the raw material in Step 1 and β was added.
Or, by performing appropriate temperature control during the gamma annealing treatment so as to contain an appropriate amount of Sn in the β and γ phases, it is possible to ensure cold ductility at the time of cold working and cutting and polishing at the time of cutting and polishing. It is possible to satisfy all of securing and corrosion resistance.

Here, taking Example (c) as an example, the raw material composition in Step 1, the crystal structure before cold drawing in Step 7, the crystal structure before cutting and polishing in Step 13,
FIG. 11 shows the physical property values. At the time of the β-annealing in Step 10, it is assumed that the crystal grain size reduction processing is also performed at the same time.

First, when looking at the raw material composition, the apparent Zn content of Comparative Example 1 is 35 wt%, while the apparent Zn content of Examples 1 to 4 is all higher. . Here, if the apparent Zn content is too large, it is difficult to increase the α phase ratio during cold working, and a γ phase that inhibits cold ductility during pregelatinizing annealing tends to precipitate. On the other hand, if the apparent Zn content is too small, it is difficult to increase the β phase ratio after cold working.
The content is preferably in the range of 33.5 to 43.5 wt%.

Next, if the Pb content is too large, the cold ductility is reduced.
% Or less, which is the same in Comparative Example 1.

Subsequently, with respect to the Sn content, Comparative Example 1
Is not contained, whereas Examples 1-4 are 0.5-
2.0 wt% is contained. This is, as mentioned earlier, β
This is for improving the corrosion resistance by securing the Sn concentration in the phase.
If the Sn content is too large, the γ phase is likely to appear during the cold working, which impairs the cold ductility.

Next, looking at the crystal structure before cold drawing, Examples 1 to 4 have a smaller α phase area ratio and a smaller crystal grain size than Comparative Example 1. However, if the area ratio of the α phase is 90% or more, elongation (indicating cold ductility) of 20% or more can be ensured, and there is substantially no hindrance to cold drawing. No problem. Incidentally, when the area ratio of the α phase becomes 95% or more,
An elongation of 35% or more is ensured, which is equivalent to Comparative Example 1.

Finally, looking at the crystal structure and physical property values before the cutting and polishing steps, Examples 1 to 4 are different from Comparative Example 1 by β
The phase area ratio is high, the average crystal grain size is small, the Sn concentration in the α and β phases is high, and good characteristics are exhibited in terms of abrasiveness, machinability and corrosion resistance. For these causal relationships,
As described above, the size of the β phase area ratio and the small average crystal grain size contribute to the abrasiveness, the size of the β phase area ratio contributes to the machinability, and the average crystal grain size to the corrosion resistance. Smallness,
The magnitude of the Sn concentration in the α and β phases contributes. In addition, the small average crystal grain size improves strength,
It also contributes to the suppression of roughening after pressing.

Here, regarding the abrasiveness, 1. 1. When the polishing is performed under the same conditions, the surface roughness after polishing is smaller than that of the conventional material. 2. When the polishing is performed under the same conditions, the polishing amount is larger than that of the conventional material. When polished under the same conditions, the overall evaluation was made from the viewpoint that there was no defect in the appearance and the plating was good compared with the conventional material, and the evaluation of the comparative material or lower was inferior (×), Those with higher evaluations than the comparative materials were evaluated as good (（).

Regarding the machinability, as a result of conducting a cutting test as described later, a free-cutting brass bar (JIS C-3604) was used.
(X), a cutting resistance index of less than 50 based on
The above was regarded as good (○). In the cutting test, as shown in FIG. 12, the peripheral surface of the sample 1 in the shape of a round plate was turned on a lathe by 100 [m / mi].
n] and 400 [m / min], and the main component force Fv was measured while cutting at two different speeds. The cutting resistance index of each embodiment is a percentage of the main component of the free-cutting brass rod, which is said to have the best machinability with respect to the main component of each embodiment. (The cutting resistance index for each cutting speed was averaged.)

As for the corrosion resistance, a dezincification corrosion test was performed according to the Japan Copper and Brass Association technical standard (JBMA T-303), and the evaluation was made according to the criteria shown in JBMA T-303. That is, when the dezincing penetration depth direction is parallel to the processing direction, the maximum dezincing penetration depth is 100 μm.
m is good (○), and when the zinc removal depth direction is perpendicular to the processing direction, the maximum zinc removal depth is 70 μm or less is good (○). ×)
And

The area ratio of the β phase is required to be at least about 5% in order to secure the machinability and abrasiveness, and to ensure the corrosion resistance, it is 30% or less, preferably 20% or less. It is sufficient that the Sn concentration therein satisfies 1.5 wt% or more. Further, the average crystal grain size may satisfy 50 μm, preferably 25 μm or less.

In a modification in which the ratio of the γ phase is increased instead of increasing the ratio of the β phase, the abrasive ratio equivalent to that of Examples 1 to 4 in FIG. , And a cutting property can be obtained. Since the γ phase has a brittle property, it is desirable that the area ratio is 30% or less and the average crystal grain size (short diameter) is 8 μm or less, preferably 5 μm or less.

Further, by setting the Sn concentration in the γ phase to 8 wt% or more and surrounding the β phase, the same corrosion resistance as in Examples 1 to 4 in FIG. 11 can be obtained.

FIG. 11 shows the embodiment (c) as an example. FIG. 13 shows another embodiment according to the embodiments (c) and (e). .

In FIG. 13, Examples 5 to 7, 9, 10, and 12
Is obtained by performing the β-annealing according to Example (c).
In Examples 8 and 11, gamma annealing according to Example (e) was performed.

Various physical properties were evaluated as follows.

* 1: Abrasiveness: The surface roughness after polishing, the amount of polishing, and the appearance after plating were evaluated.

* 2: Machinability: Free-cutting brass bar (JIS C3
The cutting resistance index based on 604) is less than 50,
0 or more was evaluated as ○.

* 3: Corrosion resistance: Japan Copper and Brass Association technical standard (J
In the dezincification corrosion test according to BMA T-303), when the maximum dezincification depth was perpendicular to the processing direction, を was given when the depth was 70 μm or less, and × was given when it exceeded 70 μm.

* 4: Flexibility: R = 1.5t (1.
Evaluation was made based on the presence or absence of surface cracks after the bending process (bending radius of 5 times) and the rough surface state.

* 5: SCC resistance: 3 vol% NH3va
In p, evaluation was made from the rupture time when a load having a proof stress ratio of 50% was applied.

* 6: Strength: 引 張 0.2 in the tensile test was 140 N / mm 2 or more, and ○ was less than 140 N / mm 2.

* 7: Elongation: Elongation is 30 in a tensile test.
% Or more was evaluated as 、, and less than 30% was evaluated as ×.

* 8: Hardness: Vickers hardness of Hv 85 or more was evaluated as ○, and hardness less than Hv 85 was evaluated as ×.

* 9: Erosion corrosion: A water penetration test was performed using a corrosive solution, and the cross-sectional structure after the test was evaluated.

As can be seen from FIG. 13, although the other physical properties slightly fluctuate, all of Examples 5 to 12 exceeded the comparative example 1 in terms of abrasion, machinability and bendability.

Next, taking Example 8 as an example, a result of quantitatively evaluating the polishing property will be described.

FIG. 14 shows the results obtained by evaluating the surface finish speed when the sample was polished under the same conditions using an automatic polishing apparatus for a sample (Buhler ECOMMET IV).

<# 600 polishing> The rotation speed of the polishing machine is 150r.
pm, sample pressing pressure 6.9 KPa, abrasive paper # 600,
Sample initial surface # 80 finish

<Buffing> Polishing machine rotation speed 200 rpm
m, sample pressing pressure 6.9 KPa, polishing powder Al2O3;
0.3μm, sample initial surface # 600 finish

As can be seen from FIG. 14, the polishing was completed in Example 8 in half the time of Comparative Example 1 in all cases.

Subsequently, taking Examples 7 and 8 as examples, FIG. 15 shows the corrosion resistance evaluation results of the straight portion and the bent portion after the bending process.

As can be seen from FIG. 15, the straight portion,
In each of the bent portions, Examples 7 and 8 are superior to Comparative Examples 1 and 2.

As another embodiment different from the above, it is possible to secure the cold ductility at the time of cold working and to perform the cutting at the time of cutting and polishing without using the β annealing treatment or the γ annealing treatment described above. There is a method that achieves compatibility with ensuring the polishing property. It is a method of precipitating a spherical γ phase having an average crystal grain size of 8 μm or less, preferably 5 μm or less at an area ratio of 3% to 30% or more. Cold cutting is not hindered, and during cutting and polishing, the cutting and polishing properties are ensured by the difference in hardness at the grain boundaries between the γ phase and other crystal phases.

[Brief description of the drawings]

FIG. 1 is a flowchart of a conventional brass plate manufacturing process and a flow of a brass plate manufacturing process according to an embodiment of the present invention.

FIG. 2 is a modified example of a brass sheet material manufacturing process flow in the embodiment.

FIG. 3 is a further modified example of the brass sheet material manufacturing process flow in the embodiment.

FIG. 4 is a temperature control diagram showing a pregelatinized annealing process in the embodiment.

FIG. 5 is a temperature control diagram showing another example of the alpha annealing treatment in the embodiment.

FIG. 6 is a temperature control diagram showing a β-annealing process (an example of a high-temperature region) in the embodiment.

FIG. 7 is a temperature control diagram showing another example of the β-annealing process (an example of a high-temperature region) in the embodiment.

FIG. 8 is a temperature control diagram showing a β-annealing process (an example of a low-temperature region) in the embodiment.

FIG. 9 is a temperature control diagram showing another example of the β-annealing process (example of a low-temperature region) in the embodiment.

FIG. 10 is a temperature control diagram showing gamma annealing treatment in the embodiment.

FIG. 11 is a list of raw material composition, crystal structure, and physical property values in the same embodiment.

FIG. 12 is an explanatory diagram of a cutting test in the embodiment.

FIG. 13 is another example of a list of raw material composition, crystal structure, and physical property values in the same embodiment.

FIG. 14 is a graph showing the evaluation results of polishing properties in the same embodiment.

FIG. 15 shows the results of evaluating corrosion resistance after bending in the same embodiment.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C22F 1/00 630 C22F 1/00 630J 640 640A 691 691B 692 692A

Claims (52)

[Claims] 1. A method for producing a brass material, comprising a heat treatment step of increasing the area ratio of a crystal phase other than the α phase after rolling. 2. The method for producing a brass material according to claim 1, wherein the heat treatment step increases the area ratio of the β phase. 3. The method for producing a brass material according to claim 1, wherein an apparent Zn content of the raw material composition is 33.5 to 43 wt%. 4. The heat treatment step is performed when the apparent Zn content is 33.5 to 43 wt%.
4. The method for producing a brass sheet according to claim 3, wherein when the apparent Zn content is 38.5 to 43 wt% in a temperature range of 550 to 800 ° C. or 400 to 500 ° C. 5. 5. The brass according to claim 2, wherein in the heat treatment step, after increasing the area ratio of the β phase by heating, the area ratio of the β phase is obtained by rapid cooling. Material production method. 6. A cooling rate up to 400 ° C. when the heating temperature range is 550 to 800 ° C., and a cooling rate up to 400 ° C. when the heating temperature range is 400 to 500 ° C. The method for producing a brass sheet material according to claim 5, wherein the material is quenched so as to be 1 ° C / sec or more. 7. The method for producing a brass sheet according to claim 2, wherein after the heat treatment step, the area ratio of the β phase is 5% or more. 8. The method for producing a brass material according to claim 1, wherein the heat treatment step increases an area ratio of a γ phase. 9. The raw material composition has an apparent Zn content of 33.5 to 43 wt% and a Sn content of 0.5 to 1.3.
The method for producing a brass material according to claim 1 or 8, which is wt%. 10. The raw material composition has an apparent Zn content of 33.5 to 43 wt% and a Sn content of 1.3 to 2.2.
The method for producing a brass material according to claim 1, wherein the content is 0 wt%. 11. The heat treatment step has an apparent Zn content of 33.5 to 43 wt% and a Sn content of 0.5 to 43 wt%.
The method for producing a brass material according to any one of claims 8 to 11, wherein when the content is 2.0 wt%, the material is heated to a temperature range of 400 to 500 ° C. 12. The method for producing a brass sheet according to claim 8, wherein after the heat treatment step, the area ratio of the γ phase is 1% or more. 13. The method for producing a brass sheet material according to claim 1, wherein cold working is performed before the heat treatment step. 14. The method according to claim 1, wherein a grain size reduction treatment is performed during the heat treatment step or during a step before the heat treatment step.
14. The method for producing a brass plate according to any one of items 13 to 13. 15. The method of manufacturing a brass material according to claim 14, wherein the crystal grain refinement treatment is performed by recrystallizing dislocations introduced by cold working by heating. 16. The method for producing a brass material according to claim 15, wherein the cold working is performed at a cross-sectional reduction rate of 20% or more. 17. The method for producing a brass sheet according to claim 14, wherein the average grain size is reduced to 50 μm or less after the crystal grain size refinement treatment. 18. The method according to claim 1, further comprising the step of:
The method for producing a brass sheet according to any one of claims 1 to 17, wherein a cutting resistance index based on a free-cutting brass bar according to IS C-3604 is 50 or more. 19. By having Sn as a raw material composition, after the heat treatment step, the Japan Copper and Brass Association technical standard JBM
When performing a dezincification corrosion test according to AT-303,
When the maximum dezincing depth direction is parallel to the processing direction, the maximum dezincing depth is 100 μm or less, or when the maximum dezincing depth direction is perpendicular to the processing direction, the maximum dezincing depth is 70 μm. The method for producing a brass plate according to any one of claims 1 to 18, which satisfies the following. 20. The method for producing a brass material according to any one of claims 1 to 19, wherein the plate material is produced. 21. The method according to claim 20, wherein the plate material is formed by casting and rolling after casting. 22. After the heat treatment step, the polishing apparatus is a burler ECOMMETIV, and the rotation speed of the polishing machine is 200 rpm.
m, sample pressing pressure is 6.9 KPa, polishing paper is SiC #
When the surface of a flaw of # 80 is polished under the condition of 600, the polishing is finished in half the time as compared with a brass tube according to Japanese Industrial Standard JISC-2700. Production method. 23. After the heat treatment step, the polishing apparatus is a burler ECOMMETIV, and the rotation speed of the polishing machine is 150 rpm.
m, sample pressing pressure is 6.9 KPa, polishing powder is Al2O
When the surface of the flaw of # 600 was polished under the condition of 3, compared with brass tubing according to Japanese Industrial Standard JISC-2700,
The method for producing a brass material according to any one of claims 20 to 22, wherein polishing is completed in half the time. 24. A method for producing a brass material having a crystal grain size refinement step after cold working. 25. A method for producing a brass sheet material having a crystal grain size refinement step. 26. A brass material produced through cold working, comprising a first phase composed of an α phase, a second phase different from the first phase, and an area ratio of the first phase. 99%
The following brass materials. 27. The brass material according to claim 26, wherein the area ratio of the β phase is 5% or more. 28. The brass material according to claim 27, wherein the area ratio of the β phase is 40% or less. 29. The Sn concentration in the β phase is 1.5 wt%.
31. The brass material according to claim 30, wherein: 30. The brass material according to claim 26, wherein the average crystal grain size is 50 μm or less. 31. The brass material according to claim 26, wherein the area ratio of the γ phase is 1% or more. 32. The brass material according to claim 31, wherein the area ratio of the γ phase is 30% or less. 33. The γ-phase having an average crystal grain size (short axis) of 8
33. The brass material according to claim 31 or 32, which has a size of not more than μm. 34. The brass material according to claim 31, wherein the Sn concentration in the γ phase is 8 wt% or more. 35. The brass material according to claim 34, wherein the brass material contains a β phase, and the γ phase surrounds the β phase. 36. The brass material according to claim 26, which is a plate material. 37. A brass plate material having an area ratio of a γ phase of 1% or more. 38. An average crystal grain of the second phase having a first phase composed of an α phase and a second phase different from the first phase, wherein the area ratio of the first phase is 99% or less. A brass tube having a diameter (short axis) of 8 μm or less. 39. A first phase comprising an α phase and a second phase different from the first phase, wherein the area ratio of the first phase is 95% or less, and the average crystal grain size is 50 μm or less. A brass plate material. 40. A brass plate having an average crystal grain size of 25 μm or less. 41. A brass sheet material satisfying a cutting resistance index of 50 or more based on a free-cutting brass bar according to Japanese Industrial Standard JIS C-3604. 42. A polishing apparatus comprising a burler ECOMET.
IV, polishing machine rotation speed 200 rpm, sample pressing pressure 6.9 KPa, polishing paper # 80 under the conditions of SiC # 600
When the scratches are polished on the surface, the Japanese Industrial Standard JIS C-
A brass plate that is polished in half the time compared to a brass plate according to 2700. 43. A polishing apparatus comprising a burler ECOMET.
IV, when the surface of a scratch of # 600 was polished under the conditions of a polishing machine rotation speed of 150 rpm, a sample pressing pressure of 6.9 KPa, and an abrasive powder of Al2O3, Japanese Industrial Standard JIS C-2
24. The method for producing a brass material according to any one of claims 20 to 23, wherein the polishing is completed in half the time as compared with the brass plate material according to 700. 44. An apparent Zn content of 33.5 to 4
A brass plate material having 3.0 wt% and a Sn content of 0.5 to 1.3 wt%. 45. An apparent Zn content of 33.5-4.
A brass plate material having 3.0 wt% and a Sn content of 1.3 to 2 wt%. 46. After hot rolling, raise the material temperature to 500-60.
A method for producing a brass sheet material, wherein the brass sheet material is maintained at 0 ° C. in the α single phase region and then rapidly cooled so that the cooling rate to 400 ° C. is 1 ° C./sec or more. 47. The method for producing a brass material according to claim 1, wherein the heat treatment step increases an area ratio of a β phase. 48. The method for producing a brass material according to claim 1, wherein an apparent Zn content of the raw material composition is 33.5 to 43 wt%. 49. The heat treatment step is performed when the apparent Zn content is 33.5 to 43 wt%.
4. The method for producing a brass sheet according to claim 3, wherein when the apparent Zn content is 38.5 to 43 wt% in a temperature range of 550 to 800 ° C. or 400 to 500 ° C. 5. 50. The brass according to claim 2, wherein, in the heat treatment step, after increasing the area ratio of the β phase by heating, a desired area ratio of the β phase is obtained by rapid cooling. The method of manufacturing the material. 51. When the heating temperature range is 550 to 800 ° C., the cooling rate to 400 ° C. is 5 ° C./sec or more,
400 ° C when the temperature range to be heated is 400 to 500 ° C
The method for producing a brass sheet material according to claim 5, wherein the material is rapidly cooled so that a cooling rate up to 1 ° C / sec or more. 52. A method for producing a brass material in which the brass sheet material obtained by the various heat treatments is hardened by cold rolling to improve dimensional accuracy and surface roughness.