Non-oriented electrical steel sheet and manufacturing method thereof
View Patent ↗A non-oriented electrical steel sheet containing: in mass %, C: 0.005% or less; Si: 0.1% to 2.0%; Mn: 0.05% to 0.6%; P: 0.100% or less; and Al: 0.5% or less, in which 10 pieces/μm 3 or less in number density of non-magnetic precipitate AlN having an average diameter of 10 nm to 200 nm are contained, and an average magnetic flux density B50 in a rolling direction and in a direction perpendicular to rolling is 1.75 T or more. This non-oriented electrical steel sheet can be manufactured by two methods of a method of performing hot rolling annealing at a temperature of 750° C. to an Ac1 transformation point and a method of setting a coil winding temperature to 780° C. or higher and performing self annealing.
1. A manufacturing method of a non-oriented electrical steel sheet, comprising:
on a slab having a steel composition containing,
in mass %,
C: 0.005% or less,
Si: 0.2% to 0.7%,
Mn: 0.05% to 0.6%,
P: 0.100% or less,
Al: 0.5% or less, and
a balance being composed of Fe and inevitable impurities,
performing hot rolling to obtain a hot-rolled steel sheet;
performing cold rolling on the hot-rolled steel sheet to obtain a cold-rolled steel sheet; and
performing finish annealing on the cold-rolled steel sheet, wherein;
in the hot rolling, a heating temperature of the slab is set to 1050° C. to 1250° C., a finish rolling finishing temperature is set to 850° C. to an Ar1 transformation point+20° C., and as part of the hot rolling, a coil winding temperature is set to 820° C. or higher, and
an annealing temperature in the finish annealing is set to 800° C. to an Ac1 transformation point.
2. The manufacturing method of the non-oriented electrical steel sheet according to claim 1 , wherein
the slab further contains, in mass %, 0.05% to 0.2% of at least one of Sn and Sb.
3. The manufacturing method of the non-oriented electrical steel sheet according to claim 1 , wherein
the slab further contains, in mass %, 0.0005% to 0.0030% of B.
4. The manufacturing method of the non-oriented electrical steel sheet according to claim 2 , wherein
the slab further contains, in mass %, 0.0005% to 0.0030% of B.