【特許請求の範囲】
【請求項１】 電磁鋼素材を熱間圧延して得られた熱延板に、１回または中間焼鈍を挟む２回以上の冷間圧延を施して最終板厚とした後、脱炭を兼ねた１次再結晶焼鈍を施し、次いで、コイル状に鋼板を巻き取った後に、該鋼板コイルをその巻取り軸が垂直になるように載置して仕上焼鈍を施す一連の工程を有する方向性電磁鋼板の製造方法において、
仕上焼鈍中に、前記鋼板コイルをその垂直方向での両端面位置が逆になるように反転させて載置し直すことを特徴とする方向性電磁鋼板の製造方法。
【請求項２】 仕上焼鈍は２次再結晶焼鈍と純化焼鈍に分けられ、２次再結晶焼鈍後に前記鋼板コイルを前記したように反転させて載置し、その後、純化焼鈍を行う請求項１に記載の方向性電磁鋼板の製造方法。
【請求項３】 仕上焼鈍にて、２次再結晶焼鈍はバッチ式焼鈍炉で行い、純化焼鈍は連続式焼鈍炉で行う請求項２に記載の方向性電磁鋼板の製造方法。
【請求項４】 前記鋼板コイルの２次再結晶条件が異なる場合、２次再結晶焼鈍は、同一の２次再結晶条件を有する鋼板コイル群ごとに別個のバッチ式焼鈍炉で行い、
純化焼鈍は、前記２次再結晶焼鈍を行った全鋼板コイルを同一の連続式焼鈍炉で行う請求項２または３に記載の方向性電磁鋼板の製造方法。
【請求項５】 ２次再結晶焼鈍は、不活性ガス雰囲気中で、９００℃以下かつ３０時間以上保持することにより行い、
純化焼鈍は、還元ガス雰囲気中で１１００℃以上かつ１０時間以下保持を行うことにより行う請求項２，３または４に記載の方向性電磁鋼板の製造方法。
【請求項６】 バッチ式焼鈍炉から連続式焼鈍炉への炉換えを大気中で行う場合には、前記鋼板コイルをバッチ式焼鈍炉内で４００℃以下に冷却してから連続式焼鈍炉に炉換えし、このとき、鋼板コイルを前記したように反転させてから連続式焼鈍炉に載置する請求項３、４または５に記載の方向性電磁鋼板の製造方法。
[Claims]
1. A hot-rolled sheet obtained by hot-rolling an electromagnetic steel material is subjected to one or two or more cold-rolling steps including intermediate annealing to obtain a final sheet thickness, and also serves as decarburization. After performing a primary recrystallization annealing, winding the steel sheet in a coil shape, placing the steel sheet coil so that its winding axis is vertical, and performing a finish annealing step. In the method for manufacturing an electrical steel sheet,
A method for producing a grain-oriented electrical steel sheet, wherein during the finish annealing, the steel sheet coil is inverted and mounted again so that the positions of both end faces in the vertical direction are reversed.
2. The finish annealing is divided into a secondary recrystallization annealing and a purification annealing, and after the secondary recrystallization annealing, the steel sheet coil is inverted and mounted as described above, and thereafter, the purification annealing is performed. 3. The method for producing a grain-oriented electrical steel sheet according to item 1.
3. The method for producing a grain-oriented electrical steel sheet according to claim 2, wherein, in the finish annealing, the secondary recrystallization annealing is performed in a batch annealing furnace, and the purification annealing is performed in a continuous annealing furnace.
4. When the secondary recrystallization conditions of the steel sheet coil are different, the secondary recrystallization annealing is performed in a separate batch annealing furnace for each steel sheet coil group having the same secondary recrystallization condition,
The method for producing a grain-oriented electrical steel sheet according to claim 2 or 3, wherein the purification annealing is performed in the same continuous annealing furnace for all the steel sheets subjected to the secondary recrystallization annealing.
5. The secondary recrystallization annealing is performed by maintaining the temperature in an inert gas atmosphere at 900 ° C. or lower and for 30 hours or longer.
The method for producing a grain-oriented electrical steel sheet according to claim 2, 3 or 4, wherein the purification annealing is performed by holding in a reducing gas atmosphere at 1100 ° C or more and 10 hours or less.
6. When the furnace is changed from a batch type annealing furnace to a continuous type annealing furnace in the atmosphere, the steel sheet coil is cooled to 400 ° C. or less in a batch type annealing furnace, and then the continuous type annealing furnace is converted to a continuous type annealing furnace. The method for producing a grain-oriented electrical steel sheet according to claim 3, 4 or 5, wherein the furnace is replaced, and at this time, the steel sheet coil is turned over as described above and then placed in a continuous annealing furnace.
すなわち、この発明の要旨は下記のとおりである。
（１）電磁鋼素材を熱間圧延して得られた熱延板に、１回または中間焼鈍を挟む２回以上の冷間圧延を施して最終板厚とした後、脱炭を兼ねた１次再結晶焼鈍を施し、次いで、コイル状に鋼板を巻き取った後に、該鋼板コイルをその巻取り軸が垂直になるように載置して仕上焼鈍を施す一連の工程を有する方向性電磁鋼板の製造方法において、仕上焼鈍中に、前記鋼板コイルをその垂直方向での両端面位置が逆になるように反転させて載置し直すことを特徴とする方向性電磁鋼板の製造方法。
That is, the gist of the present invention is as follows.
(1) A hot-rolled sheet obtained by hot-rolling an electromagnetic steel material is subjected to one or two or more cold-rolling steps with intermediate annealing to obtain a final sheet thickness, which is also used for decarburization. A grain-oriented electrical steel sheet having a series of steps of performing a subsequent recrystallization annealing, then winding the steel sheet in a coil shape, and then placing the steel sheet coil so that its winding axis is vertical and performing finish annealing. The method for producing a grain-oriented electrical steel sheet according to the above method, wherein the steel sheet coil is reversed and mounted again during finish annealing so that the positions of both end faces in the vertical direction are reversed.