JPS61190050A - Marageing steel combining high strength, high value of electric resistance, and soft magnetic property - Google Patents

Abstract

PURPOSE:To provide high strength, high electrical specific value, and soft magnetic properties by particularly specifying the content of Ni, Co, Mo, Cr, Ti, and Al in a composition of marageing steel. CONSTITUTION:The marageing steel consists of, by weight, <=0.03% C, <=0.1% Si, <=0.1% Mn, <=0.01% P, <=0.01% S, 10-22% Ni, 0.1-5% Co, 0.2-5% Mo, 0.5-5% Cr, 0.6-2% Ti, <=0.2% Al, and the balance Fe with inevitable impurities. Owing to this composition, the value of coercive force can be improved into reduced one without changing residual magnetic flux density and the value of electric resistance can be raised. This marageing steel is applicable to yoke material of high speed rotors, various relay materials and the like in the various fields of nuclear power, space navigation, industrial equipment and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a soft magnetic material having high strength and high electrical resistance.

Conventional maraging steel is an ultra-low carbon, high Ni martensitic steel that undergoes appropriate aging treatment.
Although it is known as an ultra-high-strength steel that can obtain strength above -, it is also attracting attention as a magnetic material because it has semi-hard magnetism. Recently, it has been used as a yoke material or relay material for high-speed rotating bodies in fields such as nuclear power, aerospace, and industrial equipment.It has high strength and excellent toughness, and also has high electrical resistance and soft magnetic properties. There is a growing demand for inexpensive materials.

Traditionally, permalloy alloys have been used as soft magnetic materials, but
It does not have sufficient strength when used as a high-speed rotating body. In addition, Fe-Mn material, which is a semi-hard magnet, has a coercive force of 40 to 1
If the coercive force is within this range, the shaft eccentricity will increase due to biased magnetization when magnetized as a rotating yoke, so the coercive force must be 15 Aersted or less. Further, the electrical resistance value had to be 50 μΩ or more in order to prevent the occurrence of eddy current and heat generation.

In this respect, 18Ni mardising steel has excellent toughness and strength of 140 to 4/- or more, and is suitable as a structural material for high-speed rotating bodies, but its coercive force is about 20 to 5] Therefore, it cannot be said to be sufficiently soft, and the electrical resistance value is 30 to 50 μm, so improvement was necessary.

C. Problems to be Solved by the Invention The purpose of the present invention is to provide a maraging steel that is an improved version of the conventionally developed 18Ni maraging steel and has high strength, high electrical resistance, and soft magnetic properties. be.

2. Means for Solving the Problems In order to solve the problems, the maraging steel according to the present invention, which has both high strength, high electrical resistance, and soft magnetic properties, has a C0.03% or less Si0 by weight%. .1%
Below, Mn 0.1% or less, P 0.01% or less, 5 (10
1% or less, Ni1C1-22% + Co0.1-5%,
Mo 0.2-5%, crIIL 5-5%, 'ri0.
It is characterized by containing ~2% of S and 0.2% or less of At, with the remainder consisting of Fe excluding impurities.

E. Function Next, we will discuss the reasons for limiting the above components.C is mixed as an impurity, but C exceeding α-output forms carbides with Ti etc., making it ductile.

Since C impairs toughness, it is limited to α05% or less.

Pigeon and Si are mixed as impurities, and 0.
If it exceeds 1%, an increase in the amount of non-metallic inclusions will lead to a decrease in ductility and toughness, so each is limited to less than Oj.

Ni is a constituent element of martensite, and Ni of 10es or more strengthens the steel through appropriate aging treatment in the martensitic state, and is also necessary from the viewpoint of ductility and toughness, so the lower limit is limited to 10%. Excessive addition of Ni leaves an austenite phase, lowering the strength and increasing coercive force, so the upper limit is limited to 2296.

Co is an element that precipitates Mo and Ti as a precipitation hardening accelerating element, but sufficient strength cannot be obtained with Co having a CL of less than 1%, so the lower limit is limited to 0.1%.

Although Co has little effect on increasing coercive force and is preferable in terms of magnetic properties, no improvement in strength can be expected even if excessive Co is added, so the upper limit is limited to 5% in consideration of economic efficiency.

N1d1 is also a precipitation strengthening element, and Mo less than 0.2% lowers the strength, so the lower limit is limited to 0.2%. M4
It has the effect of increasing the coercive force and increasing the electrical resistance value, but if it exceeds 5%, undissolved precipitates remain, which requires bathing treatment at a higher temperature and significantly reduces toughness, so the upper limit is set to 5%. Limited to 俤.

Cr is the most effective element for increasing electrical resistance, but less than 0.5% Cr has no effect on increasing electrical resistance, so the lower limit is limited to α5%. Excessive addition of Cr increases electrical resistance and coercive force, and also reduces ductility and toughness, so the upper limit is limited to 5.

Ti is an essential element as an age hardening element, and has a strength of at least 0. In summary, it is inevitable that excessive addition of Ti increases coercive force and decreases ductility and toughness.
is limited to 0.6-2%.

, is added as a deoxidizing agent, but if added in excess, toughness decreases due to an increase in the amount of nonmetallic inclusions.
Limited to A4 or α2% or less.

Examples of the Invention Examples of the present invention are shown below. Table 1 shows the chemical compositions of the invention steel and comparative steel. 711i9.4 shown as comparative steel
These are samples known as 175~/- and 245/- grade maraging steels, respectively.

Table 1 The produced samples were hot-rolled under normal conditions and processed into NO plates for 10 days, and after solution treatment at 820°C, they were machined into tensile test pieces, 0 Mi test pieces, and electrical resistance measurement test pieces. Then, aging treatment was performed at 480°C.

Table 2 shows the results of the tensile test, magnetism measurement, and electrical resistance measurement.

As is clear from the wc2 table, the tensile properties of the steel of the present invention are 1
Tensile strength of 50Kf/- or more. Tensile elongation of 13% or more,
It has a tensile area of 60 mm or more and has the same tensile ductility and higher strength compared to the comparative steel MU9 and 410, while it has lower strength but good ductility compared to the comparative steels MU9 and 410. has.

The magnetic properties of the steel of the present invention have a coercive force of ITO to 12.5 oersted, which is an improved coercive force lower than that of comparative steels M9 and 410 without changing the residual magnetic flux density. Furthermore, the electrical resistance of the steel of the present invention was 50 mL, which was an increase of more than 10 points compared to the comparative steels JK9 and 1610.

As stated above, the steel of the present invention is an inexpensive maraging steel with a strength of over 15oKv/-me, which combines soft magnetic properties and high electrical resistance, which were difficult to obtain with conventional maraging steels. I can say it.

G. As described in detail, the steel of the present invention has high strength, high electrical resistance, and soft magnetic properties as a yoke material for high-speed rotating bodies or various relay materials in fields such as nuclear power, aerospace, and industrial equipment. It is possible to provide maraging steel that also has the following properties, and has great industrial value.

Claims (1)

[Claims] C0.03% or less, Si0.1% or less, Mn0 in weight%
．． 1% or less, P 0.01% or less, S 0.01% or less, N
i10~22%, Co11~5%, Mo0.2~5%,
Cr0.5-5%, Ti0.6-2% and Al0.2
Maraging steel with high strength, high electrical resistance, and soft magnetic properties.