Method for manufacturing non-oriented electromagnetic steel sheet

Patent metadata

Field	Value
Publication number	US-9748027-B2
Application number	US-201314413589-A
Country	US
Kind code	B2
Filing date	Aug 8, 2013
Priority date	Aug 17, 2012
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

Provided is a method for stably obtaining a non-oriented electrical steel sheet with high magnetic flux density and excellent productivity, at a low cost by casting in a continuous casting machine a slab having a chemical composition including by mass %, C≦0.0050%, 3.0%<Si≦5.0%, Mn≦0.10%, Al≦0.0010%, 0.040%<P≦0.2%, N≦0.0040%, 0.0003%≦S≦0.0050%, Ca≦0.0015%, and total of at least one element selected from Sn and Sb: 0.01% or more and 0.1% or less, balance including Fe and incidental impurities, subjecting the slab to heating, then subjecting the slab to hot rolling to obtain a hot rolled steel sheet, then subjecting the steel sheet to hot band annealing, pickling, subsequent single cold rolling to obtain a final sheet thickness, then subjecting the steel sheet to final annealing, wherein in the hot band annealing, soaking temperature is 900° C. or higher and 1050° C. or lower, and cooling rate after soaking is 5° C/s or more.

First claim

The invention claimed is:

1. A method for manufacturing a non-oriented electrical steel sheet, the method comprising:
casting in a continuous casting machine a slab having a chemical composition comprising, by mass %:
C: 0.0050% or less;
Si: more than 3.0% to 5.0% or less;
Mn: 0.10% or less;
Al: 0.0010% or less;
P: more than 0.040% and to 0.2% or less;
N: 0.0040% or less;
S: 0.0003% or more to 0.0050% or less;
Ca: 0.0015% or more;
a total of at least one element selected from the group consisting of Sn and Sb: 0.01% or more to 0.1% or less; and
the balance including Fe and incidental, impurities;

subjecting the slab to heating;
then subjecting the slab to hot rolling to obtain a hot rolled steel sheet;
then subjecting the steel sheet to hot band annealing, pickling, and subsequent single cold rolling to obtain a final sheet thickness;
then subjecting the steel sheet to final annealing,
wherein in the hot band annealing, a soaking temperature is 900° C. or higher to 1050° C. or lower, and a cooling rate after soaking is 5° C./s or more.

2. The method for manufacturing a non-oriented electrical steel sheet according to claim 1 , wherein if the continuous casting machine is a curved continuous casting machine, a surface temperature at a center part of a slab width in a straightening zone right after the slab passes through a curved zone is set to be 700° C. or higher.

3. The method for manufacturing a non-oriented electrical steel sheet according to claim 1 , wherein the hot band annealing is performed as continuous annealing, and a difference between a maximum temperature and a minimum temperature of soaking temperature in a hot rolled sheet coil is 10° C. or more.

4. The method for manufacturing a non-oriented electrical steel sheet according to claim 2 , wherein the hot band annealing is performed as continuous annealing, and a difference between a maximum temperature and a minimum temperature of soaking temperature in a hot rolled sheet coil is 10° C. or more.

5. The method for manufacturing a non-oriented electrical steel sheet according to claim 1 , wherein the cooling rate after soaking is 25° C./s or more.

Assignees

• Jfe Steel Corp

Inventors

• Nakanishi Tadashi
• Zaizen Yoshiaki
• Oda Yoshihiko
• Toda Hiroaki

Classifications

• C21D8/1222

  Hot rolling · CPC title

• C22C38/60 Primary

  containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur · CPC title

• C21D8/1205

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

• C22C38/004

  Very low carbon steels, i.e. having a carbon content of less than 0,01% · CPC title

• B22D11/00

  Continuous casting of metals, i.e. casting in indefinite lengths (metal drawing, metal extruding B21C) · CPC title