Hot rolled silicon steel producing method

Patent metadata

Field	Value
Publication number	US-9496078-B2
Application number	US-201214372689-A
Country	US
Kind code	B2
Filing date	Mar 29, 2012
Priority date	Mar 13, 2012
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

A hot rolled silicon steel producing method comprises: silicon steel slab heating process, rough rolling process and finish rolling process. The heating process comprises a pre-heating stage, a heating stage and a soaking stage. The pre-heating stage satisfies the following formula (1). In the formula, VTp is a temperature increasing rate, in the pre-heating stage, whose unit is ° C./min; t is a total heating time of the slab in the heating furnace, and t=180-240 min; and Tc is an initial temperature when the slab is put into the furnace, whose unit is ° C. By using the foregoing formula, the heating process and the rough rolling process are changed, an occurrence rate of edge defects during the production of the hot rolled silicon steel can be reduced, and the hot rolled silicon steel with good surface quality can be produced.

V
Tp

>

220
⁢

⁢
min

t

×

100
⁢
°
⁢

⁢

C
.

T
C

+

200
⁢
°
⁢

⁢

C
.

×
25
⁢
°
⁢

⁢

C
.

/

⁢
min

(
1
)

First claim

The invention claimed is:

1. A manufacturing method of a hot-rolled silicon steel comprising a heating procedure, a rough rolling procedure, and a finishing rolling procedure on a silicon steel slab, where said heating procedure is conducted in a heating furnace comprising a preheating section, a heating section and a soaking section,
wherein,
the preheating section satisfies the following formula (1),

V
Tp

>

220
⁢

⁢
min

t

×

100
⁢
°
⁢

⁢

C
.

T
C

+

200
⁢
°
⁢

⁢

C
.

×
25
⁢
°
⁢

⁢

C
.

/

⁢
min

(
1
)

wherein,
V Tp : Increasing rate of temperature of the preheating section, ° C./min,
t: Total heating time of the slab in the heating furnace, and t=180˜240 min,
T C : Initial temperature of the slab when entering into the furnace, ° C.;
the soaking section satisfies the following formula (2-1) or (2-2),
−10° C.≦T S ≦30° C. (2-1), when the silicon content of the silicon steel is 1.5 wt % or above,
10° C.≦T S ≦80° C. (2-2), when the silicon content of the silicon steel is less than 1.5 wt %,
wherein,
T S : Temperature rise of the soaking section, i.e., the difference between the temperature of the slab when entirely taken out of the furnace and its temperature at the end of the heating section, ° C.; and
the temperature rise of the heating section satisfies the following formula (3):
temperature rise of the heating section=(temperature of the slab when entirely taken out of the furnace−temperature rise of the soaking section)−temperature at the end of the preheating section  (3),

wherein said preheating section refers to a section from an entering point at which the slab enters into the furnace to a point that is 1/6˜1/3 of the furnace length away from said entering point,
said soaking section refers to a section from an exit point at which the slab is taken out of the furnace to a point that is 1/6˜1/3 of the furnace length away from said exit point, and
said heating section refers to a section that is between the preheating section and the soaking section.

2. The manufacturing method of claim 1 , wherein 1 to 6 passes of side reduction by vertical rolling is applied in said rough rolling procedure.

3. The manufacturing method of claim 2 , wherein a reduction for each side reduction by vertical rolling is 10˜40 cm.

4. The manufacturing method of claim 2 , wherein 3 to 8 passes of horizontal reduction are applied in the rough rolling, with an accumulated reduction rate of 70˜90%.

5. The manufacturing method of claim 2 , wherein a time period from the point just after the slab is entirely taken out of the furnace to the point when the final pass of the rough rolling is completed and does not exceed 360 seconds.

6. The manufacturing method of claim 2 , wherein a slab sizing press is used in the rough rolling procedure with a side reduction ranging from 10 to 180 cm.

Assignees

• Zhang Huawei
• Wu Yaping
• Gong Yu
• Sun Yezhong
• Hei Hongxu
• Baoshan Iron & Steel

Inventors

• Zhang Huawei
• Wu Yaping
• Gong Yu
• Sun Yezhong
• Hei Hongxu

Classifications

• C21D8/1205 Primary

  involving particular fabrication steps or treatments of ingots or slabs · CPC title

• C21D2201/05

  Grain orientation · CPC title

• C21D8/1216

  characterised by the working steps · CPC title

• C21D1/26

  Methods of annealing · CPC title

• C21D8/021

  involving particular fabrication steps or treatments of ingots or slabs · CPC title