Method of producing oriented silicon-iron sheet material with boron and nitrogen additions

Claim 1

The method of producing grain-oriented silicon-iron sheet which comprises the steps of providing a silicon-iron melt containing 2.2 to 4.5 per cent silicon, amounts of manganese and sulfur within a ratio of manganese to sulfur less than 1.8, between about three and 35 parts per million of boron, and between about 30 and 70 parts per million nitrogen in the ratio to boron of one to 15 parts per part of boron, casting the melt to form an ingot, hot rolling the ingot to produce an elongated sheet-like body, heat treating the said hot-rolled body to effect at least partial recrystallization, cold rolling the said hot-rolled body and reducing its thickness to final gauge thickness without reheating the cold-worked sheet, and thereater subjecting the cold-worked sheet to a final heat treatment to decarburize it and to develop (110) [001] secondary recrystallization texture in it.

Claim 2

The method of producing grain-oriented silicon-iron sheet which comprises the steps of providing a silicon-iron melt containing 2.2 to 4.5 per cent silicon, amounts of manganese and sulfur within a ratio of manganese to sulfur less than 1.8, between about three and 35 parts per million of boron, and between about 30 and 70 parts per million nitrogen in the ratio to boron of one to 15 parts per part of boron, casting the melt to form an ingot, hot rolling the ingot to produce an elongated sheet-like body, heat treating the said hot-rolled body to effect at least partial recrystallization, cold rolling the said hot-rolled body and reducing its thickness to final gauge thickness without reheating the cold-worked sheet, and thereater subjecting the cold-worked sheet to a final heat treatment to decarburize it and to develop (110) [001] secondary recrystallization texture in it.

Claim 7

The method of producing grain-oriented silicon-iron sheet which comprises the steps of providing a silicon-iron melt containing 22 to 4.5 per cent silicon, additionally containing sulfur in amount from 0.002 to 0.05 per cent or selenium in amount from 0.002 to 0.05 per cent or sulfur and selenium in aggregate amount within the range of 0.002 to 0.05 per cent, and additionally containing 0.002 to 0.09 per cent manganese in an amount in the ratio to sulfur or to selenium or selenium plus sulfur of less than 1.8, and containing between 30 and 70 parts per million nitrogen, and finally containing incidental impurities and the balance consisting of iron, adding from three to 35 parts per million of boron to the melt and thereby establishing a nitrogen to boron ratio in the melt of one to fifteen parts of nitrogen per part of boron, casting and hot rolling to form an elongated sheet-like body, heat treating the said body to effect at least partial recrystallization, cold rolling directly to final desired thickness without reheating the cold-worked sheet, and finally heat treating the resulting sheet product to decarburize and develop (110) [001] secondary recrystallization texture in it.

Claim 8

The method of producing grain-oriented silicon-iron sheet which comprises the steps of providing a silicon-iron melt containing 22 to 4.5 per cent silicon, additionally containing sulfur in amount from 0.002 to 0.05 per cent or selenium in amount from 0.002 to 0.05 per cent or sulfur and selenium in aggregate amount within the range of 0.002 to 0.05 per cent, and additionally containing 0.002 to 0.09 per cent manganese in an amount in the ratio to sulfur or to selenium or selenium plus sulfur of less than 1.8, and containing between 30 and 70 parts per million nitrogen, and finally containing incidental impurities and the balance consisting of iron, adding from three to 35 parts per million of boron to the melt and thereby establishing a nitrogen to boron ratio in the melt of one to fifteen parts of nitrogen per part of boron, casting and hot rolling to form an elongated sheet-like body, heat treating the said body to effect at least partial recrystallization, cold rolling directly to final desired thickness without reheating the cold-worked sheet, and finally heat treating the resulting sheet product to decarburize and develop (110) [001] secondary recrystallization texture in it.

Claim 10

The method of producing grain oriented silicon-iron sheet which comprises the steps of providing a hot-rolled band of intermediate thickness containing 2.2 to 4.5 per cent silicon, between three and 35 parts per million of boron, between 30 and 70 parts per million of nitrogen in the ratio of boron of one to 15 parts per part of boron, and amounts of manganese and sulfur within a ratio of manganese to sulfur less than 1.8, heat treating the hot-rolled band to effect at least partial recrystallization of the charcteristic elongated hot-rolled band grain structure, cold rolling the hot-rolled band and reducing it to final gauge thickness without reheating the metal, and thereafter subjecting the resulting cold-worked sheet to a final heat treatment to develop (110) [001] secondary recrystallization texture in it.

Claim 11

The method of producing grain oriented silicon-iron sheet which comprises the steps of providing a hot-rolled band of intermediate thickness containing 2.2 to 4.5 per cent silicon, between three and 35 parts per million of boron, between 30 and 70 parts per million of nitrogen in the ratio of boron of one to 15 parts per part of boron, and amounts of manganese and sulfur within a ratio of manganese to sulfur less than 1.8, heat treating the hot-rolled band to effect at least partial recrystallization of the charcteristic elongated hot-rolled band grain structure, cold rolling the hot-rolled band and reducing it to final gauge thickness without reheating the metal, and thereafter subjecting the resulting cold-worked sheet to a final heat treatment to develop (110) [001] secondary recrystallization texture in it.

Claim 12

The method of producing grain oriented silicon-iron sheet which comprises the steps of providing a hot-rolled band of intermediate thickness containing 2.2 to 4.5 per cent silicon, between three and 35 parts per million of boron, between 30 and 70 parts per million of nitrogen in the ratio to boron of one to fifteen parts per part of boron, and between 0.002 and 0.10 per cent manganese and less than about 0.06 per cent sulfur, heat treating the hot-rolled band to effect at least partial recrystallization of the characteristic elongated hot-rolled band grain structure, cold rolling the hot-rolled band and reducing it to final gauge thickness without reheating the metal, and thereafter subjecting the resulting cold-worked sheet to a final heat treatment to develop (110)[001] secondary recrystallization texture in it.

Claim 13

The method of producing grain oriented silicon-iron sheet which comprises the steps of providing a hot-rolled band of intermediate thickness containing 2.2 to 4.5 per cent silicon, between three and 35 parts per million of boron, between 30 and 70 parts per million of nitrogen in the ratio to boron of one to fifteen parts per part of boron, and between 0.002 and 0.10 per cent manganese and less than about 0.06 per cent sulfur, heat treating the hot-rolled band to effect at least partial recrystallization of the characteristic elongated hot-rolled band grain structure, cold rolling the hot-rolled band and reducing it to final gauge thickness without reheating the metal, and thereafter subjecting the resulting cold-worked sheet to a final heat treatment to develop (110)[001] secondary recrystallization texture in it.