| 摘要 |
PURPOSE:To produce the title crankshaft having improved fatigue strength and excellent durability by coating amorphous forming alloy powder on the surface of the fillet part of a crankshaft compact, and irradiating the powder by laser beams to melt the powder. CONSTITUTION:The material such as high-carbon steel is forged, shaped, tempered, and machined to obtain the crankshaft compact. The powder of an amorphous forming alloy is coated on the surface of the fillet part of the compact. Fe-B, Co-B, Ni-P alloys, etc., are used as the alloy in accordance with the desired strength. The thickness of the coating is appropriately controlled to about 50-100mum. The part coated with the powder is irradiated by laser beams such as CO2 laser beams to melt the powder, and then the melt is quenched by natural cooling. As a result, a homogeneous amorphous layer 7 and a high- strength martensite layer 8 under the layer 7 are formed on the fillet parts 3 and 5 of a crankshaft pin 2 and a journal 4, hence the generation of fatigue cracks is prevented, and a crankshaft 1 having excellent durability is obtained. |
