JPS5826424B2 - Fe↓-Cr↓-Co magnetic alloy with excellent machinability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spinodal decomposition type permanent magnet alloy that has excellent machinability without impairing the good magnetic properties of the Fe-Cr-Co magnet alloy.

Here, the Fe-Cr-Co magnet alloy targeted by the present invention has Fe, Cr, and Co as basic elements, and Cr
is 15-40wt%, Co is 3-30wt% and the balance is F.
In the basic composition of e, S isMos'ri, VsWz
It refers to an alloy to which one or more of Tas Zr is added.

Fe-Cr-Co-based magnet alloys with such a composition have the same magnetic force generation mechanism as alnico magnets, which are cast-type magnet alloys, and are seen as a type.
There are major differences between the two.

There is a big difference in machinability between the two.

However, alnico alloys are almost impossible to machine, such as cutting or drilling.
The difference between Fe-Cr-Co alloys is that they can be easily machined in this way, and this difference is what makes them so attractive, and this point also gives them new functionality as permanent magnets. can.

However, this machinability is not good for all alloys of this type, and varies greatly depending on its composition, heat treatment, etc.

That is, for example, if the composition is on the high Cr side or if the heat treatment is completed at the final aging treatment 1, cutting, drilling, etc. will become difficult.

For this reason, in the past, machining was performed after casting or solution treatment, and machining was not performed after final heat treatment, especially unless the vehicle was heavy.

However, depending on such a processing process, it is not possible to meet the customer's desire to use a permanent magnet that is finally finished with high dimensional accuracy.

A major feature of this alloy is that it can produce permanent magnets with complex shapes that cannot be obtained with conventional permanent magnets by machining, but in order to make even more use of this feature, It is highly desirable that the machinability of the present alloys be improved over the entire range of their composition and independent of heat treatment.

From this point of view, the present invention uses Fe-
The purpose is to obtain a Cr-Co magnetic alloy.

In order to achieve this objective, the present invention provides Fe-Cr-C
It is characterized by the composite addition of 0.05 to 0.30 wt % S and 0.05 to 0.80 wt % Mn to an o-based magnet alloy.

Hereinafter, the present invention will be explained in detail based on examples and the like.

First, as mentioned above, the present invention is characterized by a Fe-Cr-Co based magnet alloy containing a combination of S and Mn, and the machinability of the alloy is improved by the combination of these additions. The improvement in magnetic properties does not result in a decrease in magnetic properties.

In the present invention, in consideration of this, the range of addition of S and Mn is limited as described above.

That is, 0.05 wt% or less of S and 0.05 wt% of Mn
Composite additions of less than 0.30 wt% of S and 0.80 wt% of Mn have no effect on improving machinability.
The ranges for each of the above-mentioned composite additions were determined as described above because the deterioration of magnetic properties is significant.

Here, in the present invention, S is added, but it is already well known that steel to which S is added has improved machinability as a free-cutting steel.

However, in the case of Fe-Cr-Co magnet alloy,
When added S forms a sulfide such as FeS, magnetism is significantly impaired.

On the other hand, within the composition range according to the present invention, S and M
When combined with n, it becomes a sulfide like MnS,
This precipitates at grain boundaries and within the grains and improves machinability without impairing magnetism.

Next, this will be explained based on an example of the present invention.

Example 1 Test materials having chemical components (wt %) as shown in Table 1 were used as raw materials for industrial pure iron, electrolytic cobalt, low carbon ferrochrome, ferrovanadium, low carbon ferrotitanium, and low carbon ferro Manganese and sulfur lumps were melted in a high-frequency melting furnace to make ingots.

The ingot is hot-rolled and made into a rod shape, which has a diameter of 13 mm.
It was cut to a length of 60 um.

Subsequent heat treatments included isothermal magnetic field treatment and multi-stage aging in accordance with normal procedures.

Among these samples, sample 1 has a basic composition of Fe-Cr-
Samples of Co-based magnetic alloys: sample ① is a sample according to the present invention in which Mn and S are added in combination; The sample to which ri, v, and w were added is a sample according to the present invention in which Mn and S were further added in combination.

A machinability test was conducted on this □□□ sample, but this test was conducted after multi-stage aging.

The test was conducted using 5KH-5 as a cutting tool.
Feed 0.4/rev, depth of cut 1.0 and cutting speed 1
Cutting was performed at a speed of 6 m/min.

Table 2 shows the machining time at which the cutting tool reaches a certain level of wear and the magnetic properties after the cutting test.

As shown in Table 2, it can be seen that with the magnetic alloy according to the present invention, it is possible to dramatically extend the continuous cutting time without deteriorating the magnetic properties.

Example 2 A conventional magnet alloy having the chemical components shown in Table 3 and a magnet alloy according to the present invention containing a composite addition of Mn and S were used.
Each was melted in the atmosphere in a high-frequency induction furnace and
kg of ingots were cast.

Here, the alloys marked with ■ and ■ in the table have a Co and Cr content close to the lower limit of the "claims," and the alloys marked with ■ and ■ have a Cr content "within the claims." In addition, alloys (1) and (2) have a Co content close to the upper limit of "Claims."

From the cast ingot, by hot forging and hot rolling, (A) diameter 50rrLm1 length 300mm, (B)
Two types of rod-shaped samples with a diameter of 13 mm and a length of 6011 LrIL were made.

These samples were heated at 1300°C for 30 minutes and then subjected to water-cooling solution treatment, and the sample (B) was subjected to isothermal magnetic field treatment for 2 hours at 620°C to 650°C and 60°C in order to obtain magnetic properties.
Multi-stage aging treatment was performed at 0°C to 500'C4.

These samples were tested for machinability using a lathe.

Table 4 shows the results of the machining time due to tool wear for each sample.

From these results, it can be seen that the combined addition of Mn and S to the Fe-Cr-Co magnet alloy according to the present invention can significantly extend the continuous machining time with a cutting tool.

As described above, according to the present invention, Fe-Cr-C has excellent machinability without impairing magnetic properties.

Since we can provide a system magnet alloy, it is possible to manufacture permanent magnets with complex shapes with high dimensional accuracy by cutting, and the field of application of permanent magnet alloys can be further expanded. .

Claims (1)

[Claims] 1 Fe-Cr-Co based magnet alloy consisting of 15 to 40 wt% Cr, 3 to 30 wt% Co, and the remainder Fe, 0.05
~0.80 wt%Mn and 0.05~0.3゜w
An Fe-Cr-Co magnetic alloy with excellent machinability characterized by containing tφS in combination. 2 15-40 wt% Cr, 3-30 wt% C. F consisting of 0.1 to 10 wt% of one or more of si, Mos'ri, VsWm Ta, and Zr, and the remainder Fe.
0.05 to 0.80Mn to e-Cr-Co magnet alloy
and 0.05 to 0.30 ωtφS.