JPH0741344B2 - Fe-Co alloy forging method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is directed to an alloy having a composition of Co: 30 to 60% by weight, the balance: Fe and inevitable impurities (hereinafter,
This alloy is referred to as an Fe-Co alloy) and a method for manufacturing a rod.

The Fe-Co alloy rod is cut into an appropriate length and crushed to obtain Fe-Co alloy powder. This Fe-Co alloy powder is
It is sintered together with Tb and Gd powders and used as a raw material powder for a sputtering target for forming a magneto-optical recording thin film.

[Conventional technology]

The Fe-Co alloy is first vacuum-melted into an ingot, heated for slab forging, and further heated for hot forging. Since the above Fe-Co alloy is extremely brittle, the above heating and hot forging were carefully repeated, and then hot finish forging was performed, the surface was processed, and the bar was finished.

[Problems to be solved by the invention]

In the above conventional Fe-Co alloy rod manufacturing process, heating →
It takes a long time because the hot forging process needs to be carefully repeated many times, and the Fe-Co alloy is extremely brittle.
Since the workable temperature range is as narrow as 1150 ° C to 1300 ° C, it is difficult to control the temperature. If hot working is performed outside the above temperature range, cracking occurs during hot forging, resulting in poor yield.

[Means for solving problems]

Therefore, the present inventors have solved the above problems and efficiently
As a result of conducting research to produce a Fe-Co alloy round bar, the Fe-Co alloy was vacuum-melted, and the molten metal obtained by vacuum-melting was poured into a container as close to the shape of the final raw material product as possible. By creating an ingot close to the shape of the final material product and hot forging the ingot together with the container, it is possible to omit the repeating step of heating → hot forging, and the surface of the Fe-Co alloy depends on the container. It was found that the coating prevents oxidation, prevents cracking during hot forging due to surface cooling, and facilitates processing.

This invention has been made based on such findings, Co: 20-60 wt%, the balance Fe and Fe-Co alloy consisting of inevitable impurities is vacuum-melted and cast into a metal container, the metal container The Fe-Co alloy forging method is characterized by producing a packed ingot and hot forging the ingot together with a metal container.

The reason for limiting the Fe-Co alloy of the present invention to Co: 20 to 60% by weight is that when Co is contained in an amount of less than 20% by weight or more than 60% by weight, hot working becomes easy, and conventional working methods are sufficient. This is because it is possible. The present invention is the most effective method for a Fe—Co alloy having a brittle property of Co: 20 to 60% by weight, and a more brittle Co: 40 to 60% by weight among Fe—Co alloys.

Furthermore, the requirements for the material of the metal container used in this invention are Fe
As long as it does not react with the --Co alloy and that the deformation resistance at high temperature is similar to that of the Fe--Co alloy, carbon steel and low alloy steel can be cited as materials satisfying these conditions.

〔Example〕

Next, the present invention will be specifically described based on Examples.

Fe-Co alloys with the composition shown in Table 1 are
Melted using 0kg high frequency induction heating vacuum melting furnace, inner diameter: 20
0mm × height: 560mm × wall thickness: 20mm vacuum cast into a carbon steel cylindrical container, cut the shrinkage cavity part that occurred on the top, weld it with a lid on it, packed in a cylindrical container It was created. The above ingot was heated to a temperature of 1250 ° C., hot forged together with the container, continued hot forged until the surface temperature reached 800 ° C., and formed into a round bar. The carbon steel skin of the round bar is removed by cutting to form a Fe-Co alloy round bar, and the Fe-
When the surface of the Co alloy round bar was inspected, no crack was found due to hot forging. Even if the surface temperature is 800 ℃,
The temperature of the Fe-Co alloy inside the carbon steel skin can be hot forged
It seems that the temperature was over 1150 ℃.

On the other hand, for comparison, Fe- having the composition shown in Table 1
Each Co alloy was melted using a 150 kg high frequency induction heating vacuum furnace to create an ingot with a diameter of 200 mm and a height of 560 mm, and the ingot was heated to a temperature of 1250 ° C. and hot forged, and the surface temperature was: Hot forging was continued by the conventional method until the temperature reached 1000 ° C to form a round bar. Some of the round bars hot forged by the above-mentioned conventional method are not capable of being machined due to forging cracks. Table 1 also shows the visual inspection results of forging cracks.

Although a cylindrical container was used as the container in this example, the shape of the container is not limited to this, and a container of any shape such as a prismatic container can be used, and the material of the container is low. It is also possible to use alloy steel.

According to Table 1 above, when hot forging is performed using the packed ingot, the surface temperature of the ingot during forging is 80%.
While there is no forging crack at 0 ° C, in the conventional method,
It can be seen that when the surface temperature of the ingot reaches 1000 ° C, manufacturing cracks occur, and the above-mentioned packing greatly expands the forgeable temperature range of the Fe-Co alloy.

〔The invention's effect〕

When hot forging is performed using the packed Fe-Co alloy ingot, the surface of the Fe-Co alloy material is not exposed, so that surface oxidation does not occur, and the surface temperature of the packed ingot falls below 1150 ° C. Also, since there is no forging cracking and the temperature range that can be forged is greatly expanded,
The temperature control of the material during hot forging becomes extremely easy, and by making the shape of the metal container as close as possible to the shape of the final material product, there is an excellent effect that the manufacturing process can be greatly shortened. .

Claims (1)

[Claims] 1. A Fe-Co alloy having a composition of Co: 20 to 60% by weight, the balance: Fe, and unavoidable impurities is vacuum-melted, and the vacuum-melted Fe-Co alloy is cast into a metal container to obtain the above-mentioned metal. A method for forging a Fe-Co alloy, which comprises forming an ingot packed in a container, and hot forging the ingot together with a metal container.