| 摘要 |
PURPOSE:To prevent fusion at finishing end part and to uniformly execute heat treatment on the whole surface to be heat-treated by arranging a shielding plate at finishing end part of heat treatment of the material to be processed and directly irradiating high energy beam except the finishing end part. CONSTITUTION:The shielding plate 11 is arranged at the finishing end part 5 of the material 1 to be processed. Quenching treatment is executed in order from the right side by an electron beam 3 having high energy density, but at the starting end part, the material 1 to be processed is not fused because the temp. thereof is not raised. When the quenching treatment progresses and approaches to the finishing end part 5, temp. of the material 1 to be processed is raised by heating before reaching to there. However, as the finishing end part 5 is shielded by the shielding plate 11, direct heating by the electron beam 3 is not executed. In this result, the finishing end part 5 is not fused and raised to the prescribed temp. The temp. of the finishing end part 1 is sufficiently raised to A1 transformation point by only heat conduction. After that, by self- cooling, the uniform hardened layer 2 is formed.
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