JPS6223932A - Production of non-oriented silicon steel sheet having low iron loss - Google Patents

Abstract

PURPOSE:To stably produce a non-oriented silicon steel sheet having an extremely low iron loss by subjecting a silicon steel slab contg. a specific compsn. ratio each of C, Si and Al to hot rolling and cold rolling then depositing the nitride of Ti, etc. on the surface of the steel sheet. CONSTITUTION:The silicon steel slab contg. <=0.010wt% C, <=4.0% Si and <=1.0% Al is subjected to hot rolling and cold rolling to the final sheet thickness is in succession subjected to final annealing. After the oxide on the surface of the resulted steel sheet is removed, an extra-thin tensile film is securely deposited on the steel sheet surface via the mixed phase with Fe in the steel sheet by a CVD, ion plating or ion implantation. >=1 Kinds among the nitride and/or carbide of Ti, Zr, Hf, V, Nb, Ta, Mn, Cr, Mo, W, Co, Ni, Al, B and Si, the oxide of Al, Si, Ti, Sn, Fe, Zr, Ta and Ce, the boride of Si, Ti, Nb, Ta, Al, Zr, Hf, V and W, the silicide of Mo, W, Ti, Zr and V, the phosphide of B and Bi and the sulfide of Fe and Zn are used for the above-mentioned film.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The technical content described in this specification regarding the manufacturing method of non-oriented silicon steel sheet with low core loss is that
It is related to the results of research and development on improving the properties of non-oriented silicon steel sheets by forming an ultra-thin tensile film that firmly adheres to the surface of the steel sheet through a mixed phase with Fe in the sheet.

Non-oriented silicon steel sheets are mainly used for motor stators and rotors, hydroelectric generator stators, and fluorescent lamp ballasts, but from the perspective of energy conservation, it is necessary to further reduce power loss in these devices. In order to reduce this, there has been a strong demand in recent years to further reduce the iron loss of non-oriented silicon steel sheets.

(Prior art) Conventional methods for improving the core loss of non-oriented silicon steel sheets include increasing the amount of Si or Il added to the silicon steel to increase the specific resistance, or changing the cold rolling reduction rate and final annealing temperature. It is known that a method of appropriately controlling heat cycles to optimize the orientation and size of crystal grains is effective.

Furthermore, it has been found that reducing O, N, and S in steel and inclusions such as oxides, nitrides, and sulfides in steel are effective in reducing iron loss (for example, Showa 55-9742
(Refer to Publication No. 6), but recently due to advances in steelmaking technology, 0.
Coupled with the fact that it has become possible to obtain high-purity materials in which both N and S are reduced to 30 ppm or less, it has become possible to obtain materials with significantly lower iron loss.

(Problems to be solved by the invention) Regarding the above points, in order to further reduce iron loss, we believe that the metallurgical method described above is close to its limit, and we need to overcome this limit. By introducing a physical method to form an ultra-thin tensile film made of nitride, oxide, carbide, ferride, silicide, phosphide, or sulfide on the surface of the steel plate as a separate means to This was a successful production of non-oriented silicon steel sheet with extremely low iron loss.

(Another Means to Solve the Problems) The present invention provides c: 0.010% by weight or less, Si: 4.0% by weight or less, and +1:1. A t-cJ raw steel slab containing Q% by weight or less is hot-rolled, then cold-rolled according to a conventional method to obtain a cold-rolled plate of the final thickness, followed by final annealing, and then the steel plate surface is oxidized. After removing the substances, Ti, Zr, Hf, which are firmly adhered to the steel plate surface through a mixed phase with Fe in the steel plate, are removed by CVD, ion blasting, or ion implantation.
V, Nb, Ta, Mn+ Cr, Mo,
H+ Co.

Ni, If, B, and Si nitrides and/or carbides, 8II, Sr, Ti, Sn, Fe, Zr
, Ta, and Ce oxides, Si, Ti, Nb, Ta, 8(!, Zr, I
ff, V, H boride, MO+W+TI
+ Zr+ and V silicide, B and Bi phosphide,
and a method for producing a silicon steel sheet, characterized in that it is coated with an ultra-thin tensile coating made of at least one selected from sulfides of Fe and Zn.

It was discovered that this configuration could achieve a dramatic reduction in iron loss compared to the conventional method, and the present invention was completed.

This invention will be specifically explained below based on the experimental results that led to this invention.

C: 0.00606% by weight Si: 3.20% by weight, AA
: Contains 0.7 weight ix or Mn: 0.2 weight 1.
, P: 0.015 weight! ,,S:0.0011 weight x weight N:O,0O15 weight! , 0:0.0O09 by hot rolling a silicon steel slab having a composition containing 2 by weight.
, a hot-rolled sheet with a thickness of 0 mm.

After that, it was homogenized annealed at 950°C for 3 minutes, and then cold rolled into a cold rolled plate with a thickness of 0.35 mm.

Thereafter, the surface of the steel plate was degreased, and then annealed at 980°C for 5 minutes.

After that, after removing the oxide of "2" on the steel plate surface, the above @plate surface was coated with 0.8
An ultra-thin tension film of T i tJ with a thickness of μmm was formed.

The magnetic properties of the resulting product are shown in Table 1 in comparison with those in which no ultra-thin tension film was formed (comparative material).

Table 1 As is clear from Table 1, the W of the product with an ultra-thin TiN film formed by CVD or ion blating
15150 is 1.79-1.881'l/kl? , Bs
o is 1.73 to 1.72T and does not form a tension film (comparison (in case [11'+7150: 2.19 U
kg, Bso: 1.6ST It is noted that it is extremely good compared to 1.

(Function) The reason for the remarkable magnetic properties shown in Table 1 is that the ultra-thin tension coating applies elastic tension near the surface of the steel sheet, making it easier to move the domain walls. The contribution of the fundamental component of the moon is as follows.

C causes aging deterioration, so it is preferable to have less carbon, but since decarburization is also possible in the middle of the process, 0.01 with good decarburization efficiency
0.010% by weight is acceptable.

Si is effective in increasing specific resistance, reducing eddy current loss, and improving iron strength, but if added in excess, cold rollability deteriorates, so it is limited to a range of 4.0% by weight or less. .

Δβ effectively contributes to deoxidizing steel and reducing the amount of ΔAN-based precipitates, and like Si, it is also a useful component in increasing specific resistance and reducing iron loss. If added in excess, cold rollability deteriorates, so the amount was limited to 1.0% by weight or less.

In addition, it is of course necessary to reduce harmful inclusions in the steel as much as possible in order to reduce iron loss, and for this purpose, it is sufficient to reduce the amount of N and S in the steel, as well as the ○ stars. By the way, these are N: 0.0025% by weight or less, S:
Preferably, the content is 0.0015% by weight or less, and O: 0.0020% by weight or less.

Next, in this invention, the molten steel is made into a slab by a continuous casting method or an ingot/blubber rolling method, and then hot rolled in a conventional process.

After that, the hot-rolled plate is heated to 800°C to 1000°C as necessary.
Uniform annealing is performed at a temperature range of .

In the subsequent cold rolling process, the thickness of the product plate may be determined by one cold rolling process, or the thickness of the product plate may be achieved by cold rolling twice with intermediate annealing in between.

After degreasing the surface of the final cold-rolled sheet, recrystallization annealing is performed in a temperature range of 700 to 1000°C. This includes many easy magnetization axes (
For agglomerations with strong 110) and (200) plane strength: ■It is important to develop weave.

For this purpose, conventionally known final annealing is performed at 700 to 850°C.
A two-step method may be used: one at a low temperature of about 900 to 1000 degrees Celsius and a high temperature of about 900 to 1000 degrees Celsius.

The steel sheet after recrystallization annealing is subjected to CVD after removing surface oxides.
, Ti+Zr+Hj+V+Nb+TalMn+Cr+Mo on the steel plate surface by ion brating or ion implantation.
+1LCo+Ni+ A It +B+ and Si nitride and/or carbide, A R+ Si + T+ + Sn+ Pe+ Zr
, Ta, and Ce oxides, Si, Ti+Nb, Ta
+8l, Zr, Rf, V, and W boride, Mo, kl, T1. Zr and V oxide,
A necessary condition is to form an ultra-thin tensile coating consisting of at least one selected from B and Bi phosphides and Re and Zn sulfides. The appropriate thickness of the tension coating at this time is about 0.1 to 2 μmm.

(Example) Ill IC! 0.0055% by weight, Si: 3.35% by weight
, 8 ρ: 0.68 times 1x, S: 0.0006
Weight X, N: 0.0017 Weight Nχ, 0: 0.0
After heating a steel slab having a composition containing 0.009% by weight, it was hot-rolled to a thickness of 2.0 mm, and then this hot-rolled plate was
After normalizing at 0° C. for 3 minutes, pickling was performed, and then cold rolling was performed to obtain a cold rolled sheet with a thickness of 0.35+ nm. This cold-rolled sheet was recrystallized at 980°C for 3 minutes, then pickled to remove oxides on the surface of the steel sheet, and then 3χIIF
After chemical polishing in a mixed solution of 11□0□, CVII
(No mark in Table 2) Ion blating (indicated by O in Table 2) or ion implantation (indicated by Δ in Table 2) is used to remove nitrides, carbides, oxides, hydrides, silicides, and phosphorus. Extremely thin coating of oxides and sulfides (0.5~0°8
μml′! 3r) was formed. The magnetic properties of the product at that time are shown in Table 2.

Thorn 1 ■Plexus C: o, ooa weight%, Si: 3.35 weight Nχ,
81: Includes 0.592 weight x, S: 0.005 weight x, N: 0, 0022 weight x! , 0: 0.00
A steel slab containing 1.2% by weight was heated and hot rolled to a thickness of 2.0mm, then pickled and cold rolled to an intermediate thickness of 0.7mm, and then heated to 950°C.
After an intermediate annealing for 3 minutes, a second cold rolling was performed to a final thickness of 0.35 mm.

After degreasing the surface of this cold-rolled sheet, recrystallization annealing was performed at 970°C for 3 minutes. After that, oxides on the surface of the steel sheet were removed by pickling, and then TiN (0,
An ultra-thin tensile coating (5 μmm thick) was formed. The magnetic properties of the product at that time were as follows.

B50:1.72T,,W+575o:1.85H
7kg (Effect of the invention) According to this invention, a low iron loss non-oriented silicon steel plate can be stably manufactured.

Claims (1)

[Claims] 1. A silicon steel slab containing C: 0.010% by weight or less, Si: 4.0% by weight or less, and Al: 1.0% by weight or less is hot rolled, and then cooled according to a conventional method. A cold-rolled sheet with the final thickness is obtained by inter-rolling, followed by final annealing, and after removing oxides on the surface of the steel sheet,
Ti, Zr, Hf, V, Nb, Ta, Mn, Cr, Mo firmly adhered to the steel plate surface through a mixed phase with Fe in the steel plate by CVD, ion plating or ion implantation.
, W, Co, Ni, Al, B, and Si nitrides and/or
or carbide, Al, Si, Ti, Sn, Fe, Zr, Ta, and Ce
oxides of Si, Ti, Nb, Ta, Al, Zr, Hf, V, W borides, silicides of Mo, W, Ti, Zr, and V, phosphides of B and Bi, and Fe and Zn. 1. A method for producing a silicon steel sheet, which comprises coating the silicon steel sheet with an ultra-thin tensile coating made of at least one sulfide selected from the group consisting of sulfides.