| 摘要 |
<p>PURPOSE:To provide a simple and cheap multi-layered composit member having high fatigue strength, anti-corrosion and all-weather characteristics by providing an outer layer of a specified multi-layered composit member with some residual compressive stress. CONSTITUTION:An inner layer 2 is made of material for facilitating an induction heating by a high frequency and an outer layer 1 is made of such a material as an induction heating is impossible or extremely difficult but having a superior solidity. Both layers are molten fitted fast to an integral form, the inner layer is rapidly heated by a high frequency wave while the outer layer is being cooled so as to keep its normal temperature. Thermal stress is generated due to an expansion and elongation of the inner layer and a restriction by the outer layer, and thereby after cooling of them a residual stress is generated. When the assembled multi-layered composit member is used as a structural member, its fatigue strength, in particular bending fatigue strength is extremely improved and the residual compressive stress is effective to improve its anti-corrosive and all-weather characteristics.</p> |
