摘要:
내마모성이 현저하게 향상한 롤 외층재 및 압연용 복합 롤을 제공한다. W 함유량이 지름 방향으로 외주측으로부터 내주측을 향하여 저하하는 경사 조성이고, 압연 사용시의 최대 지름에 상당하는 위치의 외층재 표면에서, 질량%로, W: 25∼70%, Co: 5∼45%를 포함하고, 추가로 C: 0.6∼3.5%, Si: 0.05∼3%, Mn: 0.05∼3%, Mo: 1∼15%를 함유하고, 잔부가 불가피적 불순물로 이루어지는 W-Co기 합금 조성을 갖는 롤 외층재로 한다. 롤 외층재는, 원심 주조제로 하는 것이 바람직하다.
摘要:
PROBLEM TO BE SOLVED: To provide an external layer material of a rolling roll which is excellent in wear resistance, resistance to rough surface and resistance to accident, and the rolling roll using the same. SOLUTION: The external layer material of the rolling roll has, by area, 0.5-5% graphite, 0.1-10% MC base carbide and 10-45% cementite in the metallic structure and the spheroidizing rate of the MC base carbide is ≥0.5. Chemical composition consists of, by mass, >0.3 to 4.0% C, ≤3.0% Si, 2.3-5.5% Ni, 1.0-2.0% Cr, 0.3-10.0% V, 0.005-0.5% one or two kinds of Mg or Ca and the balance Fe with impurity elements and the spheroidizing rate of the MC base carbide in the metallic structure is ≥0.5. COPYRIGHT: (C)2005,JPO&NCIPI
摘要:
PURPOSE:To prevent the generation of defects occuring in the crease and oxidation formed on the inside surface of molten metal by blowing a nonoxidative liquefied gas refrigerant to the molten metal surface formed on the inside surface of a rotary mold by centrifugal force. CONSTITUTION:After molten metal is teemed into a mold under rotation, a nonoxidative liquefied gas refrigerant (liquid nitrogen, liquiefied carbon dioxide) is immediately sprayed on the molten metal surface of a cylindrical shape formed by centrifugal force. The inside surface of the molten metal is cooled uniformly; at the same time, the inside of the mold is put in the nonoxidative atmosphere in the mold by the evaporating gas. In this way, the formation of the crease and oxide on the inside surface of the molten metal is prevented.