JP2757695B2 - Manufacturing method of semi-process non-oriented electrical steel sheet with excellent magnetic properties - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a semi-process non-oriented electrical steel sheet having excellent magnetic properties.

[0002]

2. Description of the Related Art Methods for producing non-oriented electrical steel sheets are roughly classified into a full process method and a semi-process method. In the latter semi-process method, a steel sheet is punched or sheared into a predetermined shape on a customer side. Thereafter, a predetermined magnetic characteristic is obtained by performing strain relief annealing. Many methods for producing this semi-process material have been proposed in the prior art. For example, Japanese Patent Application Laid-Open Nos. 1-119174, 63-255323 and 64-73022 disclose cold rolling. After annealing, a high-pressure skin pass is performed to obtain predetermined magnetic properties. Also, JP-A-63-47332 and JP-A-63-4
In No. 7334, the final cold rolling is performed after cold rolling and annealing, and then the strain relief annealing is also performed on the manufacturer side to improve the magnetic properties.

[0003]

In a conventional method for producing a semi-processed material, hot rolling, hot-rolled sheet annealing, cold rolling, annealing, and temper rolling are performed, and the strain relief annealing after processing is performed on the customer side. The aim is to improve the magnetic properties after performing. By the way, when applying the insulating film after temper rolling in a continuous annealing furnace equipped with an insulating film device, if the steel sheet is passed through a normal high-temperature operating furnace, not only does the energy cost increase, but also the strain is removed. The magnetic properties after annealing also tend to deteriorate. On the other hand, if the furnace is operated at a low temperature in order to avoid this, there is a problem that the charging chance in the manufacturing process is restricted, and the productivity is reduced.

The present invention has been made in view of such a problem, and there is no deterioration in magnetic properties after strain relief annealing on the customer side, and a high productivity and a small loss from the viewpoint of energy cost. An object of the present invention is to provide a method for producing a process non-oriented electrical steel sheet.

[0005]

In order to achieve the above object, the method of the present invention comprises: C: 0.01 wt% or less;
0.1 to 1.6 wt%, Mn: 0.7 wt% or less, P:
0.12 wt% or less, S: 0.01 wt% or less, Al:
0.4 wt% or less, Si + Al: 2 wt% or less, with the balance being
A silicon steel slab substantially made of Fe is formed into a thin plate through hot rolling and cold rolling, which is continuously annealed and then temper-rolled.
This is a method for producing a semi-process non-oriented electrical steel sheet having excellent magnetic properties, wherein annealing is performed at 0 to 450 ° C. for 5 to 180 seconds, and then an insulating film is formed on the steel sheet surface.

[0006]

According to the present invention, in consideration of energy cost and magnetic properties after strain relief annealing at a customer, the steel sheet after temper rolling is passed through a continuous annealing line having an insulating film apparatus.
It has been completed by finding an operating furnace temperature range that can improve the final magnetic properties. That is, in the present invention, the temper-rolled steel sheet is treated in a continuous annealing facility having an insulating coating apparatus by 30%.
The annealing is performed continuously at 0 to 450 ° C., and thereafter, an insulating film is formed.

FIG. 1 shows the relationship between the annealing temperature after temper rolling of a steel sheet and the final magnetic properties after work-strain relief annealing. FIG. 1 shows that the annealing temperature was increased from 300 ° C. by 50 ° C.
The final magnetic characteristics _{B 3, B 50, W 10} /50, W is plotted measured at _15/50. According to the figure, it is understood that when the annealing temperature exceeds 450 ° C., the final magnetic properties deteriorate. On the other hand, when the annealing temperature is lower than 300 ° C., there is a problem that the charging chance is reduced due to the restriction in the manufacturing process as described above, and the productivity is reduced. For the above reasons, in the present invention, continuous annealing after temper rolling is performed at 300 to 450.
Performed at ° C. If the annealing time is less than 5 seconds, the effect of annealing cannot be sufficiently obtained.
Exceeding 0 seconds undesirably increases the furnace length and energy cost.

Next, the reasons for limiting the component composition of the steel sheet will be described. If C exceeds 0.01 wt%, the magnetic properties deteriorate, and magnetic aging also poses a problem.
% As the upper limit. Si is 0.1 wt% from the viewpoint of reducing iron loss.
% Is set as the lower limit, but if it exceeds 1.6 wt%, the magnetic flux density in a high magnetic field is reduced, and the cost is increased. Therefore, the upper limit is 1.6 wt%. Mn converts S in steel to MnS
Has an effect of improving the grain growth during strain relief annealing, but exceeding 0.7 wt% rather deteriorates the magnetic properties and increases the cost.
The upper limit is 7 wt%.

Although P is effective in improving the punching property, the upper limit is 0.12 wt% from the viewpoint of cost. S is an element harmful to magnetic properties, and regulates the total amount of MnS deposited.
The upper limit is 0.01 wt%. Al has a great effect of reducing iron loss like Si, but if it exceeds 0.4 wt%, the magnetic flux density will be significantly reduced, so the upper limit is 0.4 wt%. In addition, from the viewpoint of preventing a decrease in magnetic flux density, Si +
The upper limit of Al is 2 wt%.

[0010] In the method of the present invention, continuous annealing and temper rolling after cold rolling are performed in a conventional manner. That is, continuous annealing is 6
5 to 180 seconds at 50 to 800 ° C.
It is performed at a rolling reduction of 10%.

[0011]

Example: C: 0.0035 wt%, Si: 0.35 w
t%, Mn: 0.50 wt%, P: 0.10 wt%,
S: 0.005 wt%, Al: 0.003 wt%, the remaining steel and slab composed of unavoidable impurities are made into a thin plate through normal hot rolling and cold rolling, and continuously annealed at 710 ° C. for 45 seconds. After temper rolling at a reduction of 6.5%, continuous annealing was performed at 300 ° C. for 45 seconds to produce a semi-processed material. Table 1 shows the magnetic properties of this steel sheet after processing and strain relief annealing.

[0012]

[Table 1]

[0013]

According to the present invention described above, a semi-process non-oriented electrical steel sheet which does not cause deterioration of magnetic properties after processing-strain relief annealing is manufactured with high productivity while minimizing energy loss. be able to.

[Brief description of the drawings]

FIG. 1 is a graph showing the effect of annealing temperature after temper rolling on magnetic properties after strain relief annealing.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C21D 8/12 C21D 9/46 501

Claims (1)

(57) [Claims] 1. C: 0.01 wt% or less, Si: 0.1
1.6 wt%, Mn: 0.7 wt% or less, P: 0.1
2 wt% or less, S: 0.01 wt% or less, Al: 0.4
wt% or less, Si + Al: 2 wt% or less, balance substantially
A hot rolled and cold rolled silicon steel slab is formed into a thin plate, which is continuously annealed and then temper-rolled. In a continuous annealing facility equipped with an insulating film device, 300 to 45
A method for producing a semi-process non-oriented electrical steel sheet having excellent magnetic properties, comprising annealing at 0 ° C. for 5 to 180 seconds, and then forming an insulating film on the steel sheet surface.