| 摘要 |
PURPOSE:To enable detection of a defect positively and handily, by a method wherein oil is attached to the surface of a cast product, the oil is removed from the surface thereof and the surface thereof is dried after rinsing with hot water to visually inspect a seepage of oil into the dried surface portion. CONSTITUTION:A cast product 1 is immersed into oil in the antirust treating process to attach the oil to the entire surface thereof. Then, after the oil attached to the surface of the product is removed, the product undergoes a phosphoric acid treatment and the surface of the product 1 is dried after rinsing by being immersed into a hot water. After it is dried, when a defect 2 such as crack and flaw exists, a seepage 3 generates about the defect 2, making it clearly distinguishable from other parts 4 of the dried parts by visual observation. This enables positive and handy detection of a defect of a cast product.
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