JPH0356298B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a Ni-Fe-Cu alloy, that is, a free-cutting magnetic alloy with improved machinability such as Cu permalloy machinability and punchability. Permalloy has been widely used as a material for electrolytic equipment and magnetic shielding. For shielding purposes, it is widely used as magnetic head shield cases and shield covers in the audio and VTR fields. For these applications, JIS-PC equivalent materials, which are high-Ni permilos with particularly high magnetic permeability among permilosites, are mainly used, but they are relatively expensive, so lowering the price is desired industrially. ing. Therefore, the amount of expensive Ni is lower than the conventional JIS
-Cu permalloy has been attracting attention in recent years because it can be produced at a cost of about 7 to 25% less than PC equivalent materials. The basic composition of this Cu permalloy is wt%
(hereinafter simply %) Ni57~74%, Cu12~34%, Fe
It is the remainder and contains a large amount of Cu. As a result, it becomes more flexible and sticky than conventional JIS-PC equivalent materials, resulting in poor machinability and shortened tool life. In particular, the magnetically shielded case of the VTR audio control head has several holes for fixing screws, and the holes are also tapped. Therefore, when Cu permalloy is used for the above applications, it is necessary to improve its free machinability. Generally, in order to improve the free machinability of Ni-Fe magnetic alloys, low-melting elements that do not form a solid solution with the Ni-Fe alloy are added to disperse them as fine metal grains in the alloy, thereby improving machinability. Further, a method of improving machinability by incorporating a large amount of impurities or nonmetallic inclusions into the alloy has been considered. However, in the former method, the hot workability is significantly deteriorated and the magnetic permeability is reduced, and in the latter method, the magnetic permeability is also reduced. The present invention enables Ni-
The purpose is to provide a magnetic alloy with improved machinability of Fe-Cu alloy. The present invention has Ni57~74%, Cu12~32%, Be0.001~
0.5%, 10% or less Ti, Zr, V, Nb, Ta, Cr,
At least one selected from Mo, W, Mn, Ge,
By producing a free-cutting magnetic alloy consisting of Fe and the balance Fe, the machinability of this type of alloy is improved without impairing hot workability or magnetic properties. Next, the reason for limiting the alloy composition will be explained. Ni has high permeability in the range of 57-74%,
If Ni is less than 57%, the magnetic permeability decreases and the corrosion resistance is significantly inferior, and if it exceeds 74%, the magnetic permeability decreases significantly due to the addition of 12% or more of Cu. In addition, Ni is 74
% or more is industrially disadvantageous if resource conservation and price reduction are taken into consideration. Cu has high magnetic permeability in the range of 12 to 32%, but Cu
If the Cu content is less than 12%, high magnetic permeability cannot be obtained unless the Ni content exceeds 74%, and if the Cu content exceeds 32%, the initial permeability decreases and hot workability deteriorates even if the Ni content is less than 57%. In order to obtain high magnetic permeability within the above composition range for both Ni and Cu, it is necessary to conversely increase the amount of Cu as the amount of Ni decreases. Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn,
Ge 10 to improve magnetic properties and mechanical properties
%. The preferred addition range of each additive element is Ta, W, and Mn, respectively.
10% or less, V, Nb, Cr, Mo, Ge each 6
% or less, Ti2% or less, Zr1% or less. If these elements are added in excess of the above range, hot workability will deteriorate, saturation magnetic flux density will decrease, and machinability will also deteriorate. Be is an element added to improve machinability, and it has the effect of improving chip breakage.If it is less than 0.001%, its effect is not obvious, and if it is added more than 0.5%, the machinability is significantly reduced. There is no improvement, and the deterioration of magnetic permeability becomes even more significant. Next, the present invention will be explained with reference to Examples. An alloy having the chemical composition shown in Table 1 was vacuum melted and then cast to obtain an ingot. These ingots are hot-forged at a suitable temperature range of 900-1250℃.
A plate-shaped sample with a thickness of 6 mm was obtained by hot rolling. At this time, hot workability was good in all cases. A 50 x 50 x 6 test piece was cut out from these samples and heated to 900°C.
It was annealed for 1 hour (in a hydrogen atmosphere) and subjected to a machinability test. Further, the plate-shaped sample was cold-rolled to a thickness of 0.5 mm, and a ring-shaped sample having an outer diameter of 10 mm and an inner diameter of 6 mm was punched out, and annealed at 1100° C. for 3 hours (in a hydrogen atmosphere) to measure magnetic properties.

[Table] Atsuta.
Drilling was performed for each alloy shown in Table 1, and the cutting resistance at this time was measured. Cutting resistance was measured separately into torque and thrust components using a tool dynamometer. Furthermore, the cutting torque during tapping was also measured. The cutting conditions at this time are summarized in Table 2, and the measurement results are shown in Table 4. In addition, the measurement items of magnetic properties are shown in Table 3, and the measurement results are shown in Table 4.

【table】

【table】

[Table] According to

[Table] Next, Figures 1 and 2 show the relationship between feed rate and cutting resistance during drilling for No. 1, No. 3, and No. 9. Figure 1 shows the results for the torque component, and Figure 2 shows the results for the thrust component. From these figures, it can be seen that the torque component and the thrust component of the alloy No. 9 of the present invention are smaller than those of Comparative Examples No. 1 and 3, that is, the cutting resistance is smaller. Furthermore, Fig. 3 shows the cutting torque during tapping for the same alloy. From this figure, the invention alloy No.
It can be seen that No. 9 has a smaller cutting resistance than Comparative Examples Nos. 1 and 3. As shown in the above examples, preferred composition ranges for the alloy of the present invention include Ni in a range of 60 to 69% and Cu in a range of 16 to 30% in terms of magnetic properties. As mentioned above, Ni57-74%, Cu12-32%,
Be0.001~0.5%, 10% or less Ti, Zr, V, Nb,
An alloy consisting of at least one selected from Ta, Cr, Mo, W, Mn, Ge and the balance Fe, that is, Cu
By incorporating an appropriate amount of Be into permalloy, it is possible to improve machinability without impairing hot workability or magnetic properties. Therefore, the alloy of the present invention
It is extremely useful as a magnetic head case for VTRs, and is also useful as a material for various electromagnetic devices that are subjected to other cutting processes.

[Brief explanation of drawings]

FIGS. 1 and 2 are diagrams showing the relationship between tool feed rate and cutting resistance during drilling, and FIG. 1 shows the torque component of the cutting resistance, and FIG. 2 shows the thrust component. FIG. 3 is a diagram showing the cutting torque for each material during tapping.

Claims (1)

[Claims] 1 Weight% Ni57-74%, Cu12-32%,
Be0.001~0.5%, 10% or less Ti, Zr, V, Nb,
A free-cutting magnetic alloy comprising at least one selected from Ta, Cr, Mo, W, Mn, and Ge, and the balance being Fe.