TWI504752B - Non-directional electromagnetic steel sheet with tissue - optimized and its manufacturing method - Google Patents

Description

Non-directional electromagnetic steel sheet optimized by collective organization and manufacturing method thereof

The present invention relates to an electromagnetic steel sheet and a method of manufacturing the same, and more particularly to a non-directional electromagnetic steel sheet optimized for assembly and a method of manufacturing the same.

The iron loss of the electromagnetic steel sheet includes eddy current loss and magnetic hysteresis loss, the former is related to the resistivity and the alloy content, and the latter is related to the grain size and the aggregate structure.

It is known that in order to reduce the eddy current loss of the electromagnetic steel sheet, a high amount of alloy is generally added, mainly a niobium alloy, to increase the electrical resistivity. However, the addition of a high amount of niobium alloy system may cause the thermal conductivity of the steel to deteriorate, so that the steel strip is easily controlled by the cooling rate during the final annealing process, resulting in the formation of residual stress, which in turn causes the magnetic hysteresis loss to rise.

In addition, the <001> direction of the conventional electromagnetic steel sheet is the most easy to magnetize direction, because the steel magnetization requires the least amount of energy, so when the steel has significant Goss-{110}<001>, Cube-{100}<001> or When the assembly of the composition is approximated, it is often characterized by low iron loss and high magnetic flux density.

A method for forming a surface on a surface of an iron or an iron-based alloy sheet, forming a {100} texture, a method for producing a non-oriented electrical steel sheet, and a non-oriented electrical steel sheet, as disclosed in Japanese Laid-Open Patent Publication No. I342339 The γ→α phase metamorphism in the demanganization process is used to form a high content {100} texture, thereby reducing the iron loss of the non-oriented electrical steel sheet and increasing its magnetic flux density. However, the above method requires the addition of expensive manganese and nickel alloys at high prices, resulting in a substantial increase in production costs. In addition, the above method also needs to strictly control the annealing atmosphere, so the steel coil needs to be demanganized in a vacuum environment or needs to be coated with dioxide. The powder is so fine that the method is difficult to implement on a high-efficiency industrial line.

Therefore, it is necessary to provide an innovative and progressive assembly-optimized non-directional electromagnetic steel sheet and a method of manufacturing the same to solve the above problems.

The invention provides a method for manufacturing a non-directional electromagnetic steel sheet with optimized tissue organization, the manufacturing method comprising the steps of: (a) providing a steel embryo, the composition of the steel embryo comprising less than 0.01% by weight of carbon, 0.1 to 3.5 weight At least one of a group consisting of %, 0.1 to 1.5% by weight of manganese, 0.1 to 2.0% by weight of aluminum, 0.005 to 0.1% by weight of phosphorus, 0.005 to 0.1% by weight of bismuth and tin, less than 0.01 5% by weight of sulfur, less than 0.01% by weight of nitrogen and the rest are substantial iron and unavoidable impurities, and the cerium content S, the manganese content M, the aluminum content A and the phosphorus content P satisfy the following conditions: (3S+M+2A+ 2P) <13.0% by weight; (b) heating the steel embryo; (c) hot rolling the steel blank to form a steel sheet; (d) performing an annealing treatment step on the steel sheet; (e) cold rolling the steel sheet to a Intermediate thickness; (f) steps (d) and (e) are repeated in sequence until the steel sheet is cold rolled to a final thickness to form an electromagnetic steel sheet; and (g) a final annealing step is performed on the electromagnetic steel sheet.

The invention further provides a non-oriented electromagnetic steel sheet with optimized organization, the composition comprising: less than 0.01% by weight of carbon; 0.1 to 3.5% by weight of bismuth; 0.1 to 1.5% by weight of manganese; 0.1 to 2.0% by weight of aluminum 0.005 to 0.1% by weight of phosphorus; 0.005 to 0.1% by weight of at least one of the group consisting of bismuth and tin; less than 0.01% by weight of sulfur; less than 0.01% by weight of nitrogen; and the balance being substantially iron and Inevitable impurities; among them, strontium content S, manganese content M, aluminum content A and phosphorus content P satisfy the following conditions: (3S+M+2A+ 2P) <13.0% by weight.

The manufacturing method of the invention can significantly improve the Goss-{110}<001> aggregate structure strength of the non-directional electromagnetic steel sheet, and does not inhibit the grain growth, so the non-directional electromagnetic steel sheet produced has low iron loss. And the dual characteristics of high magnetic flux density. In addition, the non-directional electromagnetic steel sheet optimized by the assembly organization of the present invention can be applied to the manufacture of high efficiency motors, variable frequency motors, electric vehicle drive motors, servo motors, high speed spindle motors and high efficiency transformer cores.

The above description is only an overview of the technical solutions of the present invention, and the technical means of the present invention can be more clearly understood, and the objects, features, and advantages of the present invention can be more clearly understood. The preferred embodiment will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a flow chart showing the manufacturing method of the non-directional electromagnetic steel sheet optimized by the assembly of the present invention. Referring to step S11 of FIG. 1 , a steel embryo is provided, the composition of which includes less than 0.01% by weight of carbon, 0.1 to 3.5% by weight of bismuth, 0.1 to 1.5% by weight of manganese, 0.1 to 2.0% by weight of aluminum, 0.005 to 0.1% by weight of phosphorus, 0.005 to 0.1% by weight of at least one of the group consisting of bismuth and tin, less than 0.01% by weight of sulfur, less than 0.01% by weight of nitrogen, and the balance being substantially iron and inevitable Impurities. In the present embodiment, the niobium content S, the manganese content M, the aluminum content A, and the phosphorus content P must satisfy the following conditions.

(3S+M+2A+2P)<13.0% by weight (1)

Referring to step S12, the steel embryo is heated. The heating temperature for this step is 1200 to 1250 ° C, and preferably, the heating time is 2 to 4 hours.

Referring to step S13, the steel blank is hot rolled to form a steel sheet. In this step, the thickness of the steel sheet is 1.5 to 3.5 mm.

Referring to step S14, the steel sheet is subjected to an annealing treatment step. In the present embodiment, the annealing treatment step is performed at a temperature ranging from 700 to 1100 ° C, and the annealing time is from 2 minutes to 30 hours. Preferably, the steel sheet is subjected to a pickling process prior to the annealing step.

Referring to step S15, the steel sheet is cold rolled to an intermediate thickness. In this step, the cold rolling rate needs to be 30 to 80%.

Referring to step S16, steps S14 and S15 are sequentially repeated until the steel sheet is cold rolled to a final thickness to form an electromagnetic steel sheet. In the present embodiment, steps (d) and (e) must be repeated at least twice in sequence, and the process conditions are set to condition (2). Preferably, the number of repetitions of the steps should be 2 to 3 times to avoid too many times and time consuming and energy consuming. Further, the final thickness is 0.1 to 0.5 mm.

Referring to step S17, a final annealing step is performed on the electromagnetic steel sheet. In this embodiment, the final annealing step is performed at a temperature ranging from 900 to 1100 ° C, and the annealing time is from 30 seconds to 10 minutes so that the final grain size is greater than 80 μm.

The manufacturing method of the invention can significantly improve the Goss-{110}<001> aggregate structure strength of the non-directional electromagnetic steel sheet, and does not inhibit the grain growth, so the non-directional electromagnetic steel sheet produced has low iron loss. And the dual characteristics of high magnetic flux density.

The assembly-optimized non-directional electromagnetic steel sheet prepared according to the manufacturing method of the present invention comprises: less than 0.01% by weight of carbon; 0.1 to 3.5 weight 量% by weight; 0.1 to 1.5% by weight of manganese; 0.1 to 2.0% by weight of aluminum; 0.005 to 0.1% by weight of phosphorus; 0.005 to 0.1% by weight of at least one of the group consisting of bismuth and tin; 0.01% by weight of sulfur; less than 0.01% by weight of nitrogen; and the balance being substantial iron and unavoidable impurities; wherein the cerium content S, the manganese content M, the aluminum content A and the phosphorus content P satisfy the above condition (1). The non-directional electromagnetic steel sheet optimized by the assembly organization of the invention can be applied to the manufacture of high efficiency motors, variable frequency motors, electric vehicle drive motors, servo motors, high speed spindle motors and high efficiency transformer cores.

The invention is illustrated by the following examples, which are not intended to be limited to the scope of the invention.

Invention examples and comparative examples:

The steel composition of the invention examples and comparative examples are listed in Table 1, and the unit is % by weight. As listed in Table 1, the inventive examples and comparative examples were composed of five different steel materials, A, B, C, D, and E, wherein the strontium content S was 3.5, 3.0, 2.0, 0.8, and 2.5% by weight, respectively; The contents were 0.55, 1.20, 0.45, 0.75 and 0.42% by weight, respectively; the aluminum contents A were 1.50, 1.85, 0.85, 0.30 and 1.60% by weight, respectively; and the phosphorus contents P were 0.025, 0.060, 0.023, 0.055 and 0.015% by weight, respectively. The carbon, sulfur and nitrogen contents not shown in Table 1 were both about 0.004% by weight, and the cerium content was about 0.08% by weight, the balance being substantial iron and unavoidable impurities. In addition, according to the calculation result of condition (1), the A steel material and the B steel material system do not conform to the condition (1).

The steel embryo produced by the agglomeration or continuous casting is heated in an oven at 1220 ° C for 2 hours; then, hot rolled into a steel plate having a thickness of about 2 mm; the steel plate is subjected to pickling once, respectively, or Annealing and cold rolling more than one time until the final thickness is formed to form an electromagnetic steel sheet; after that, the electromagnetic steel sheet is placed in an annealing furnace at 1000 ° C for 90 seconds to make the final grain size of the steel sheet larger than 95 Micron. The detailed process conditions are listed in Table 2.

It is worth noting that the comparative examples A-1, B-1 and B-2 in which the steel composition does not conform to the condition (1) are fractured during the first cold rolling, so that it is impossible to carry out subsequent multiple annealing and cold rolling. .

The output of the electromagnetic steel sheet is measured by the iron loss value (W15/50) and the magnetic flux density (B50), where W15/50 indicates that the excitation frequency is 50 Hz and is excited to 1.5 Tesla. Iron loss value; B50 represents the magnetic flux density obtained when the excitation frequency is 50 Hz and the magnetic field strength is 5000 A/m. The measurement results of W15/50 and B50 are listed in Table 3.

Figure 2 is a graph showing the Goss-{110}<001> aggregate tissue intensity distribution of Comparative Example D-1 of the present invention. Figure 3 is a graph showing the Goss-{110}<001> aggregate tissue intensity distribution of Inventive Example D-3 of the present invention. Figure 4 shows a comparative example E-2 of the present invention. Goss-{110}<001> aggregate tissue intensity map. Figure 5 is a graph showing the Goss-{110}<001> aggregate tissue intensity distribution of Inventive Example E-5 of the present invention. Comparing Fig. 2 with Fig. 3 and Figs. 4 and 5, respectively, it can be seen that the Goss-{110}<001> aggregate structure strength of the inventive examples D-3 and E-5 can be increased by about 5 times. Further, from the measurement results of Table 3, it is also known that the iron loss of each of the inventive examples of the present invention is remarkably lowered, and the magnetic flux density of each of the invention examples is also remarkably improved.

The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the scope of the present invention. The scope of the invention should be as set forth in the appended claims.

1 is a flow chart showing a method for manufacturing a non-directional electromagnetic steel sheet optimized by the assembly of the present invention; FIG. 2 is a view showing a Goss-{110}<001> collective tissue intensity distribution map of Comparative Example D-1 of the present invention; The Goss-{110}<001> aggregate tissue intensity distribution map of the inventive example D-3; FIG. 4 shows the Goss-{110}<001> aggregate tissue intensity distribution map of Comparative Example E-2 of the present invention; and FIG. The Goss-{110}<001> aggregate tissue intensity distribution map of Inventive Example E-5 of the present invention.

Claims (12)

A method for manufacturing a non-directional electromagnetic steel sheet with optimized organization, comprising the steps of: (a) providing a steel embryo, the composition of the steel embryo comprising less than 0.01% by weight of carbon, 0.1 to 3.5% by weight of ruthenium, 0.1 to 1.5% by weight of manganese, 0.1 to 2.0% by weight of aluminum, 0.005 to 0.1% by weight of phosphorus, 0.005 to 0.1% by weight of at least one of the group consisting of cerium and tin, less than 0.01% by weight of sulfur, less than 0.01% by weight of nitrogen and the rest are substantial iron and unavoidable impurities, and the cerium content S, the manganese content M, the aluminum content A and the phosphorus content P satisfy the following conditions: (3S+M+2A+2P)<13.0% by weight (b) heating the steel embryo; (c) hot rolling the steel blank to form a steel sheet; (d) performing an annealing treatment step on the steel sheet; (e) cold rolling the steel sheet to an intermediate thickness; (f) Steps (d) and (e) are repeated in sequence until the steel sheet is cold rolled to a final thickness to form an electromagnetic steel sheet; and (g) a final annealing step is performed on the electromagnetic steel sheet. The manufacturing method according to claim 1, wherein the heating temperature of the step (b) is 1200 to 1250 °C. The manufacturing method according to claim 1, wherein the heating time of the step (b) is 2 to 4 hours. The manufacturing method according to claim 1, wherein the steel sheet of the step (c) has a thickness of 1.5 to 3.5 mm. The manufacturing method according to claim 1, wherein the annealing treatment step of the step (d) is carried out at a temperature ranging from 700 to 1100 °C. The manufacturing method according to claim 5, wherein the annealing time of the step (d) is from 2 minutes to 30 hours. The manufacturing method according to claim 1, wherein the cold rolling ratio of the step (e) is from 30 to 80%. The manufacturing method according to claim 1, wherein the step (f) repeats the steps (d) and (e) at least twice in sequence. The manufacturing method according to claim 1, wherein the final thickness of the step (f) is 0.1 to 0.5 mm. The manufacturing method according to claim 1, wherein the final annealing step of the step (g) is carried out at a temperature ranging from 900 to 1100 °C. The manufacturing method according to claim 10, wherein the annealing time of the step (g) is from 30 seconds to 10 minutes. An assembly-optimized non-directional electromagnetic steel sheet comprising: less than 0.01% by weight of carbon; 0.1 to 3.5% by weight of bismuth; 0.1 to 1.5% by weight of manganese; 0.1 to 2.0% by weight of aluminum; 0.005 to 0.1% % by weight of phosphorus; 0.005 to 0.1% by weight of at least one of the group consisting of bismuth and tin; less than 0.01% by weight of sulfur; less than 0.01% by weight of nitrogen; The rest are substantial iron and unavoidable impurities; wherein the cerium content S, the manganese content M, the aluminum content A, and the phosphorus content P satisfy the following condition: (3S+M+2A+2P) <13.0% by weight.