Silicon steel product with low iron loss for low-noise transformer, and manufacturing method thereof

Patent metadata

Field	Value
Publication number	US-11633808-B2
Application number	US-201716336095-A
Country	US
Kind code	B2
Filing date	Jun 13, 2017
Priority date	Sep 29, 2016
Publication date	Apr 25, 2023
Grant date	Apr 25, 2023

Abstract

An oriented silicon steel product with a low iron loss for a low-noise transformer, and manufacturing method thereof are provided. The oriented silicon steel product comprises: a silicon steel substrate, a magnesium silicate bottom layer formed on a surface of the silicon steel substrate, and an insulation coating applied on the magnesium silicate bottom layer. The magnesium silicate bottom layer has a visible light normal reflectivity (R) of 40-60% for. By strictly controlling the visible light normal reflectivity of the magnesium silicate bottom layer of the silicon steel substrate and the evenness of the gloss of magnesium silicate bottom layer, lower iron loss, and reduced magnetostriction can be achieved, and thus a silicon steel product with low noise and particularly suitable for transformers can be obtained.

First claim

The invention claimed is:

1. An oriented silicon steel product with low iron loss for a low-noise transformer, comprising a silicon steel substrate, a magnesium silicate bottom layer formed on a surface of the silicon steel substrate having a thickness of 0.5-3 μm, and an insulation coating applied on the magnesium silicate bottom layer, wherein the magnesium silicate bottom layer has a visible light normal reflectivity R of 40-60%;
wherein R has a statistical distribution σ in 100 mm 2 of the magnesium silicate bottom layer of 7.5 or less; and
wherein the silicon steel substrate consists of the following chemical elements by mass percentages:
C: 0.035-0.120%, Si: 2.5-4.5%, Mn: 0.05-0.20%, S: 0.005-0.012%, acid-soluble Al: 0.015-0.035%, N: 0.004-0.009%, Cu: 0.01-0.29%, Sn: 0.08-0.20%, Nb: 0.05-0.10%, the balance being Fe and other unavoidable impurities.

2. The oriented silicon steel product with low iron loss for a low-noise transformer according to claim 1 , wherein the magnesium silicate bottom layer has a visible light normal reflectivity R of 45-55.3%.

3. The oriented silicon steel product with low iron loss for a low-noise transformer according to claim 1 , wherein the statistical distribution σ of R in 100 mm 2 of the magnesium silicate bottom layer is 4 or less.

4. The oriented silicon steel product with low iron loss for a low-noise transformer according to claim 1 , wherein the magnesium silicate bottom layer has a surface roughness R a of 0.13-0.48 μm.

5. The oriented silicon steel product with low iron loss for a low-noise transformer according to claim 1 , wherein the steel product has a thickness of 0.30 mm or less and an iron loss of 1.02 W/Kg or less.

6. A manufacturing method for the oriented silicon steel product with low iron loss for a low-noise transformer of claim 1 , comprising the following steps in turn:
(1) smelting and casting;
(2) hot rolling;
(3) normalizing;
(4) cold rolling;
(5) decarburization annealing to reduce the carbon content in the silicon steel substrate to 30 ppm or less and the oxygen content to 2.0 g/m 2 or less; a nitriding treatment is performed before, after or simultaneously with the decarburization annealing to control the nitrogen content in the silicon steel substrate to 150-350 ppm; wherein in the heating stage, there is a rapid heating stage in which the initial temperature is 600° C. or less, the final temperature is 700° C. or more, and the heating rate is 80° C./s or more; in addition, the difference between oxidation potentials in the heating stage and oxidation potentials in the holding stage of decarburization annealing protective atmosphere satisfies the following formula:

(

P

H
2

⁢
O

P

H
2

)

Holding

-

(

P

H
2

⁢
O

P

H
2

)

Heating

=

A
·

log
10

⁡

(

V
h

)

100
×

[
Sn
]

in the formula, A is the technological coefficient of oxidation potential; P H 2 O and P H 2 are partial pressures of H 2 O and H 2 in decarburization annealing protective atmosphere, respectively, in units of Pa; V h is the heating rate of rapid heating stage, in units of ° C./s; [Sn] is the content of Sn in the substrate, in units of %;
(6) high-temperature annealing: before the high-temperature annealing, the surface of the silicon steel substrate is coated with an annealing separator, wherein the annealing separator contains MgO;
(7) applying an insulation coating;
(8) laser scribing: scribing lines perpendicular to the rolling direction is formed on the surface of the product by laser scribing, wherein parameters of the laser scribing satisfy the following formula:

0.4
≤

p
·
a
·

exp
⁡

(

-

R

λ
0

)

d

≤
2

in the formula, p is the energy density of the incident laser, in units of mJ/mm 2 ; a is the length of the focused spot of laser in rolling direction, in units of mm; R is the visible light normal reflectivity of magnesium silicate bottom layer, in units of %; d is the spacing of scribing lines in rolling direction, in units of mm; λ 0 is the wavelength of incident laser, in units of nm.

7. The manufacturing method according to claim 6 , wherein the technological coefficient A of oxidation potential ranges from 0.08 to 1.6.

8. The manufacturing method according to claim 6 , wherein the energy density p of the incident laser is 50-200 mJ/mm 2 .

9. The manufacturing method according to claim 6 , wherein the length a of the focused spot of laser in rolling direction is 0.08 mm or less.

10. The manufacturing method according to claim 6 , wherein in step (8), the residence time of laser on the surface of the product is no more than 0 . 005 ms.

11. The manufacturing method according to claim 6 , wherein in step (6), the holding temperature of annealing is 1150-1250° C., and the holding time is 15 hr or more.

12. The manufacturing method according to claim 6 ,

Assignees

• Baoshan Iron & Steel

Inventors

• Zhao Zipeng
• Hou Changjun
• Xiang Banglin
• Shen Kanyi
• Li Guobao
• Ling Chen
• Xie Weiyong
• Song Yanli

Classifications

• C22C38/04

  containing manganese · CPC title

• C22C38/008

  containing tin · CPC title

• B23K26/361 Primary

  for deburring or mechanical trimming (B23K26/351 takes precedence) · CPC title

• C21D8/1244

  characterised by the heat treatment · CPC title

• C22C38/00

  Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00) · CPC title