JPS5813605B2 - Manufacturing method of magnetic silicon steel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cube-on-edge
orientation and at least 1 8 in 10 oersteds
The present invention relates to a method for producing magnetic silicon steel having a magnetic permeability of 50 G/Oe.

Oriented silicon steel containing 2.60 to 4.0% silicon is generally produced by a process consisting of hot rolling, double cold rolling, annealing before each cold rolling, and high temperature microstructural annealing. Ru.

In recent years, a number of patents have announced silicon steels with magnetic permeability of greater than 1850 G/Oe at 10 Oe.

Among these, from the viewpoint of processing method, US Patent No. 3, 28
7,1 8 3, 3,6 2 3,4 5 6 and 3,6 3 6,5 7 9 are of most interest.

U.S. Patent No. 3,287,183, 1966
It was published on November 22, 2017, and this indicates that the steel is
950°C to 1200°C to precipitate AIN
It has been announced that steel consisting of specific amounts of carbon, silicon, aluminum, sulfur and iron can be processed into high magnetic permeability silicon steel by annealing at a temperature of .

Subsequently, U.S. Pat.
, 6 3 6, 5 7 9, a substantially similar treatment method for similar alloy steels was published.

These patents all relate to cooling followed by annealing in which AIN is precipitated.

In the former case, the temperature ranges from 750°C to 12°C depending on the silicon content.
The hot rolled steel strip is annealed at 00° C., the annealed steel strip is rapidly cooled, and then it is subjected to at least two cold rollings.

In the latter case, at a temperature of 950°C to 1200°C, 2
．． Steel containing 5 to 4.0% silicon is annealed and rapidly cooled from said temperature to at least 400 DEG C., after which it is cold rolled.

Another interesting one is U.S. Patent No. 3,1 5 9,5 1
No. 1, which discloses a method for producing silicon steel in a single cold rolling, which
There is no way to make silicon steel with a magnetic permeability as high as 50 G/Oe.

More specifically, this describes a processing method in which silicon steel is hot rolled and immediately thereafter cold rolled.

What is described here is that a steel with a special composition has an edge-cubic orientation and at least 1
An improved method for manufacturing silicon steel having a magnetic permeability of 850 Q/Oe.

The method includes annealing a hot rolled steel strip at a temperature of 790 to 926° C. for a period of 15 seconds to 2 hours, cooling the hot rolled steel strip to room temperature in still air, and A single cold rolling consists of the steps of cold rolling said cooled steel with a reduction rate of at least 80%.

This method differs from and is incompatible with the methods of the above-mentioned US patents in the following points.

That is, in U.S. Patent No. 3,159,511,
At 10 Oersted, 1 8 5 0 Q/Oe
There is also a method for making silicon steel with moderately high magnetic permeability.
At a temperature of 790°C to 926°C for a period of seconds to 2 hours,
There is also no indication of annealing the hot rolled steel strip; US Pat. No. 3,287,183 indicates a minimum annealing temperature of 950°C, but a maximum annealing temperature of 926°C. Does not indicate temperature, U.S. Patent No. 3,63
2,4 5 6 contains virtually at least 2.5% Si.
Annealing of hot rolled strip steel at an excess temperature of 950° for steel containing No. 3,636,579 states that at least 2.5%
A minimum annealing temperature of 950°C for Si-containing steel and rapid cooling from said annealing temperature have been shown.

Furthermore, the chemical composition of the steel processed according to the present invention is also different from that in each of the above-cited US patents.

It is therefore an object of the present invention to provide a method for making a magnetic silicon steel having an edge cubic orientation and a magnetic permeability of at least 1850 G/Oe at 10 Oe.

The treatment method according to the invention comprises up to 0.07% carbon, 2.60 to 4.0% silicon, and 0.03 to 0.0% by weight.
24% manganese, 0.01-0.07% sulfur, 0.015-0.04% aluminum, 0.0
Preparing a melt of silicon steel containing up to 2% nitrogen and 0.1 to 0.5% steel, casting said steel, and hot rolling said steel to make a steel strip. , annealing the hot rolled steel strip, cold rolling the annealed steel strip, subjecting the steel to a decarburization treatment, and subjecting the steel to a final textural annealing.

Furthermore, the following special processing is included as an important step.

That is, from 790°C to 926°C for 15 seconds to 2 hours.
annealing the hot rolled steel strip at a temperature of , cooling the annealed hot rolled steel strip to room temperature in still air;
Cold rolling the cooled steel with a reduction rate of at least 80% in a single cold rolling.

Furthermore, it is advantageous to include the conditions that the hot rolled steel strip is annealed at a temperature of 790° C. to 890° C. and cold rolled with a reduction rate of at least 85%.

For purposes of limitation, cooling at room temperature in still air does not include cooling in which steel is cooled under static atmospheric pressure, and unless there is an intention to intentionally create movement for the purpose of cooling. It is understood to include cooling where there is relative movement between the atmosphere and the steel, such as in continuous processing lines.

Additionally, and again by way of limitation, any gaseous atmosphere is assumed to have the same cooling effect as air.

Therefore, unless a quenching liquid or forced gaseous atmosphere is used, any open cooling is equivalent to room temperature cooling in still air.

A forced gaseous atmosphere refers to one in which movement is intentionally imparted for the purpose of cooling.

The above-mentioned melting, casting, hot rolling, annealing, cold rolling, decarburization and final structure annealing do not involve any new measures as far as technology is concerned.

Regarding these, any steel manufacturing technique may be applied to the present invention.

However, annealing the hot rolled steel strip at temperatures between 790°C and 926°C is important as this provides the steel with conditions suitable for cold rolling and provides a period of action during which the inhibitor is formed. 926° C. is particularly advantageous, further contrasted with the presence of austenite and ferrite phases and different solubilities for inhibiting elements within each phase, etc. at slightly higher temperatures.
It is of paramount importance that the evenness in which the inhibitor is distributed is promoted so that within the following steel there is primarily only a ferrite phase.

As inhibitors, the present invention mainly specifies aluminum nitride, manganese sulfide, and/or manganese sulfide steel, which will be described in further detail later.

There are no special standards regarding the atmosphere for annealing.

Therefore, examples of such ambient air include nitrogen, reducing gases such as hydrogen, inert gases such as argon, air, and mixtures thereof.

With regard to cold rolling, several passes through the rolling bed constitute one cold rolling, and multiple cold rolling operations were performed only when the cold rolling operations were separated by annealing. I have to point out that this is happening.

The molten steel must contain silicon, aluminum, manganese, sulfur and copper.

Silicon is necessary to increase the resistivity of the steel, reduce its magnetic strain, reduce the magnetic anisotropy of the crystal, and thus reduce iron losses.

Aluminum, manganese and sulfur are necessary to form inhibitors which are important in controlling the orientation and properties based thereon of the steel.

More specifically, aluminum combines with nitrogen in the steel or in the atmosphere to form aluminum nitride, and manganese combines with sulfur to form manganese sulfide and/or manganese copper sulfide.

These compounds act to suppress the formation of particles during final annealing of the structure, and at the same time, form secondary recrystallized particles with the desired cube-on-edge orientation. Helps development.

In addition to the possibility of forming copper manganese sulfide, it is believed that copper can lower the annealing temperature, increase the rollability, simplify melting, and ease the annealing atmosphere requirements. It is useful in being able to hypothesize hypothetically.

In particular, the steel to which the method of the present invention can be applied mainly contains 0.02 to 0.07% carbon, 2.60 to 3.5% silicon, and % Mn + (0.1 +0.
25) Manganese equivalent to 0.05% to 0.24 and 0.01 to 0.05 expressed by the equivalent formula ×%Cu.
% sulfur, 0.015 to 0.4% aluminum, 0.0030 to 0.0090% nitrogen, 0.
．． It consists of 1 to 0.3% copper, the balance iron and residue, and in the above, the ratio of manganese equivalent to sulfur is within the range of 2.0 to 4.75.

The chemical composition of this steel is balanced to create a particularly advantageous structure when processed according to the invention.

The following examples demonstrate several features of the invention.

Three specimens of silicon steel (specimens 1 to 3) were cast from one batch of BOF silicon steel with an edge-cubic orientation.
Processed into silicon steel.

This steel mainly contains, by weight, 0.049% carbon, 2.91% silicon, 0.094% manganese, 0.032% sulfur, and 0.036% aluminum. 0.0046% nitrogen, 0.22% copper, and the balance iron and residue.

The treatments for the above three specimens include immersion in water at high temperature for several hours, making steel ingots, hot rolling to a standard size of about 2.3 mm, and annealing in nitrogen at a temperature of 802°C for 1 hour. cooling by one of the following two methods,
cold rolling to a final dimension of approximately 0.33 mm, 80
It consists of a decarburization treatment for 2 minutes in a mixture of nitrogen and moist hydrogen at 2°C, and finally annealing in hydrogen at up to 1121°C for 8 hours.

The above two cooling methods are in-furnace cooling and air cooling.

Sample 1 is cooled in the furnace, sample 2 is air cooled, and sample 3 is cooled in the furnace.
was subjected to salt water quenching.

Specimens 1-2 were tested for magnetic permeability and iron loss.

The results are shown in Table I below. From Table 3 above, it is clear that Sample 2 has extremely high magnetic permeability.

That is, it is 1850 G/Oe or more at 10 Oe.

Specimen 2 was processed according to the present invention.

Specimen 2 was annealed in hydrogen at 802°C for 1 hour, then air cooled, and cold rolled in a single cold roll with a reduction of 86%.

Specimen 1 was also subjected to the same treatment as in the previous case, except that it was subjected to furnace cooling from the annealing temperature.

Unlike sample 2, sample 1 has a relatively low magnetic permeability.

It also has a significantly higher iron loss than sample 2.

It will be apparent to those skilled in the art that the novel principles of the invention, described above with specific embodiments, suggest various other variations and applications thereof.

Therefore, when interpreting the claims, the scope of the claims should not be limited to specific embodiments.

Claims (1)

[Claims] 1. Up to 0.07% carbon by weight; 2.6 to 4.
0% silicon and 0.03 to 0.24% manganese,
0.01-0.07% sulfur and 0.015-0.07% sulfur.
04% aluminum, up to 0.02% nitrogen, 0
．． preparing a molten silicon steel containing 1 to 0.5% copper; casting the steel; making a hot-rolled steel strip from the steel; annealing the hot-rolled steel strip; A cube-on-edge method comprising the steps of cold rolling the annealed hot rolled steel strip, decarburizing the steel, and subjecting it to a final structural annealing.
) orientation and at least 18 in 10 elsde
790° C. to 926° C. for a period of 15 seconds to 2 hours in a method for producing magnetic silicon steel having a magnetic permeability of 50 G/Oe.
annealing the hot rolled steel strip at a temperature of at least 80% in a single cold rolling; An improved method for producing magnetic silicon steel comprising the steps of cold rolling said cooled steel strip at a reduced rate.