| 摘要 |
PROBLEM TO BE SOLVED: To obtain a scale which can be demagnetized at a high temperature by a method wherein heat is applied, at prescribed intervals, to a heat-resistant base material which can be ferromagnetically quenched and hardened, a magnetic characteristic is changed, residual magnetization which is larger than that of the base material is generated and one out of the base material and a heated and molten part is set to the Curie point of higher. SOLUTION: A sheetlike carbon steel S35C base material 1 is irradiated with an electron beam 3 at an output of 0.1 to 15 kW, at a sweep rate of 0.1 to 15.0m/min, at an irradiation energy of 20kJ/m to 300kJ/m per unit length and in the focal position of the beam in a range of 0 to±100mm from the surface of the base material. A part 2 which has been irradiated with the electron beam 3 is heated and melted suddenly, and, when the electron beam 3 is moved in succession, the irradiated part 2 is cooled and solidified suddenly. Thereby, a part which has been swept by the electron beam 3 is subjected to a sudden heating and cooling action in a line shape or a plane shape, residual magnetization is generated, and a region which has the Curie point of 100 deg.C or higher is formed.
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