JPH07113149A - Corrosion resistant electromagnetic stainless steel - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an electromagnetic stainless steel material having at least the same level of corrosion resistance and more excellent magnetic properties. [Structure] Consists of 15 to 25% by weight of chromium, 0.5 to 5% by weight of silicon, 0.2 to 8% by weight of cobalt, balance iron and inevitable impurities.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a corrosion resistant electromagnetic stainless steel material having excellent magnetic properties.

[0002]

2. Description of the Related Art A chromium-silicon-iron alloy is known as a corrosion-resistant electromagnetic stainless steel material. The alloys of this system have corrosion resistance, coercive force of about 1.0 Oe, and magnetic flux density of about 10.2 kG as magnetic characteristics, so that they are used for iron cores of relay mechanisms such as electromagnetic valves and electromagnetic pumps. It is used.

[0003]

In recent years, however, the miniaturization of the above-mentioned parts for iron cores has led to the demand for high responsiveness, which is accompanied by excellent magnetic characteristics, that is, a lower coercive force and a higher coercive force. There is a strong demand for materials having magnetic flux density. However, the above alloy cannot sufficiently meet such a demand.

In view of the above-mentioned circumstances, an object of the present invention is to improve the alloy of this system and to provide a material having at least the same level of corrosion resistance as that of the alloy and more excellent magnetic properties.

[0005]

In order to achieve the above object, the present inventor has conducted intensive studies and found that the addition of cobalt is effective, and arrived at the present invention. That is, the present invention is
It is a corrosion-resistant electromagnetic stainless steel material comprising 15 to 25% by weight of chromium, 0.5 to 5% by weight of silicon, 0.2 to 8% by weight of cobalt, balance iron and inevitable impurities.

[0006]

The corrosion-resistant electromagnetic stainless steel material of the present invention may be either a sintered body or an ingot. Further, in the component composition of the present invention, chromium is an element contributing to the improvement of corrosion resistance, and if it is less than 15% by weight, this contribution is not sufficient, while if it exceeds 25% by weight, the magnetic properties are poor. Further, silicon is an element necessary for obtaining magnetic properties, and if the content is less than 0.5% by weight, the magnetic properties are insufficient, and if it exceeds 5% by weight,
The magnetic flux density and workability at the time of post-processing are reduced.

In the present invention, it is important to further add cobalt. With this addition, the coercive force and magnetic flux density are significantly improved as compared with the conventional material. If the addition rate of cobalt is less than 0.2% by weight, it has only the same magnetic properties as the conventional material, and if it exceeds 8% by weight, the corrosion resistance decreases.

The corrosion-resistant electromagnetic stainless steel material of the present invention can be manufactured by a known method such as a melt casting method, a powder metallurgy method (including a method utilizing a powder injection molding method).

[0009]

【Example】

Examples 1 to 7 and Comparative Examples 1 to 3 An iron-chromium-silicon alloy powder having an average particle diameter of 22 μm and a cobalt powder having an average particle diameter of 3 μm were mixed with a V blender, and 2
After kneading with the paraffin wax of weight%, the pressure is 2.0.
Press molding was carried out at 00 kgf / cm ² to obtain a ring-shaped molded body having an outer diameter of 20 mm, an inner diameter of 10 mm and a height of 10 mm. These molded bodies were debindered in vacuum at 700 ° C. for 30 minutes and then sintered at 1350 ° C. for 2 hours.

The obtained sample was subjected to chemical analysis and measurement of magnetic properties and corrosion resistance. The magnetic properties were measured for coercive force and magnetic flux density by using a Thiophie DC self-recording magnetometer. Further, the corrosion resistance was measured by measuring the pitting potential according to the “method for measuring the pitting potential of stainless steel” defined in JIS G0577, and the acid total immersion test was performed at room temperature using 5% by weight sulfuric acid aqueous solution and 5% by weight hydrochloric acid aqueous solution, respectively. It was evaluated by measuring the corrosion weight loss after time immersion. The results obtained are shown in Table 1.

[0011]

[Table 1]

According to Table 1, in all of Examples 1 to 7, the coercive force and magnetic flux density were significantly improved as compared with Comparative Example 1 which was a conventional material. Regarding the corrosion resistance, all of Examples 1 to 5 are comparable to Comparative Example 1 which is a conventional material, and Examples 6 and 7 are improved.

[0013]

EFFECTS OF THE INVENTION The stainless steel material according to the present invention has corrosion resistance equivalent to or better than conventional materials in a severe environment containing hydrogen ions, chlorine ions, etc., and has significantly improved magnetic properties. It brings a remarkably excellent effect.

Claims (1)

[Claims] 1. 15 to 25% by weight of chromium, 0.5 to 5
Corrosion resistant electromagnetic stainless steel material consisting of weight% silicon, 0.2 to 8 weight% cobalt, balance iron and inevitable impurities.