Manufacturing method of non-oriented electrical steel sheet
View Patent ↗A steel having a predetermined composition is hot-rolled so as to form a steel strip, the steel strip is subjected to first cold-rolling, the steel strip is subjected to intermediate annealing, the steel strip is subjected to second cold-rolling, and the steel strip is subjected to finish annealing. A finish temperature in the hot-rolling is 900° C. or less, annealing is not performed between the hot-rolling and the first cold-rolling, and a rolling reduction in the second cold-rolling is not less than 40% nor more than 85%.
1. A manufacturing method of a non-oriented electrical steel sheet, comprising:
performing hot-rolling of a steel material so as to form a steel strip, the steel material containing, in mass %:
Si: not less than 0.1% nor more than 4.0%;
Al: not less than 0.1% nor more than 3.0%; and
Mn: not less than 0.1% nor more than 2.0%;
a C content being 0.003% or less, and
a balance being composed of Fe and inevitable impurity elements;
next, performing first cold-rolling of the steel strip, wherein a rolling reduction in the first cold-rolling is not less than 31.4% nor more than approximately 40%;
next, performing intermediate annealing of the steel strip;
next, performing second cold-rolling of the steel strip; and
next, performing finish annealing of the steel strip at a temperature of not less than 950° C. nor more than 970° C. so as to cause recrystallization in which crystal grains in { 110 }<001> orientation grow, wherein
a finish temperature in the hot-rolling is 900° C. or less,
the first cold-rolling is started without performing annealing after the hot-rolling; and
a rolling reduction in the second cold-rolling is not less than 40% nor more than 85%.
2. The manufacturing method of a non-oriented electrical steel sheet according to claim 1 , wherein the steel material contains, in mass %, one or two selected from a group consisting of Sn: not less than 0.02% nor more than 0.40% and Cu: not less than 0.1% nor more than 1.0%.
3. The manufacturing method of a non-oriented electrical steel sheet according to claim 1 , wherein the steel material contains, in mass %, P: 0.15% or less.
4. The manufacturing method of a non-oriented electrical steel sheet according to claim 2 , wherein the steel material contains, in mass %, P: 0.15% or less.
5. The manufacturing method of a non-oriented electrical steel sheet according to claim 1 , wherein the steel material contains, in mass %, Cr: not less than 0.2% nor more than 10.0%.
6. The manufacturing method of a non-oriented electrical steel sheet according to claim 2 , wherein the steel material contains, in mass %, Cr: not less than 0.2% nor more than 10.0%.
7. The manufacturing method of a non-oriented electrical steel sheet according to claim 3 , wherein the steel material contains, in mass %, Cr: not less than 0.2% nor more than 10.0%.
8. The manufacturing method of a non-oriented electrical steel sheet according to claim 4 , wherein the steel material contains, in mass %, Cr: not less than 0.2% nor more than 10.0%.
9. The manufacturing method of a non-oriented electrical steel sheet according to claim 1 , wherein a rolling reduction in the first cold-rolling is not less than 31.4% nor more than 38.9%.