Abstract:
PROBLEM TO BE SOLVED: To provide an oriented electromagnetic steel plate with a groove for refining magnetic domain, which oriented electromagnetic steel plate can attain reduced iron loss when assembled into a real transformer and has excellent iron loss characteristics at the real machine.SOLUTION: The thickness a(μm) of an insulation coating film in the bottom surface of a linear groove, the thickness a(μm) of the insulation coating film on the steel plate surface outside the linear groove, and the depth a(μm) of the linear groove are regulated so that they satisfy the following formulae (1) : 0.3 μm≤a≤3.5 μm and (2): a+a-a≤15 μm.
Abstract:
PROBLEM TO BE SOLVED: To provide a non-oriented electromagnetic steel sheet that exhibits a minimized variation in magnetic properties in a coil and has excellent magnetic properties at every part of the coil, even if a primary recrystallization annealing step is performed through a rapid heating treatment.SOLUTION: In a method for manufacturing the non-oriented electromagnetic steel sheet, the primary recrystallization annealing step includes the steps of: carrying out a heating procedure to a temperature range of 700°C or higher at a temperature rising rate of 150 °C/s or more by a direct heating mode; subsequently carrying out a cooling procedure to a temperature range of 700°C or less; and subsequently carrying out a re-heating procedure to a soak temperature at an average temperature rising rate of 40 °C/s or less by an indirect heating mode.
Abstract:
A golf shaft includes: a hollow tubular structure; and a gradient structure in which an amount of retained austenite is increased from an approximate center in a thickness direction of the hollow tubular structure to a surface of the hollow tubular structure.
Abstract:
PROBLEM TO BE SOLVED: To provide a method for manufacturing a grain-oriented electromagnetic steel sheet from an inhibitor-free base material, which can stably obtain an effect of reducing iron loss by rapid heating treatment, when subjecting a cold-rolled sheet to primary recrystallization annealing including the rapid heating treatment. SOLUTION: In a process of manufacturing the grain-oriented electromagnetic steel sheet by preparing a steel slab reduced to the contents of 100 ppm or less Al and 50 ppm or less N, S and Se respectively, which are all inhibitor components, hot-rolling the steel slab, cold-rolling the hot-rolled steel slab once, or twice or more sandwiching intermediate annealing to the final sheet thickness, subjecting the cold-rolled sheet to primary recrystallization annealing, and then subjecting the resultant cold-rolled sheet to secondary recrystallization annealing, the primary recrystallization annealing includes the steps of: heating the cold-rolled sheet to a temperature region of 700°C or higher at a heating speed of 150°C/s or more, then cooling the heated steel sheet to a temperature region of 700°C or lower once, and heating the cooled steel sheet to a soaking temperature in the next heating zone on a condition that the average heating speed is 40°C/s or less. COPYRIGHT: (C)2011,JPO&INPIT