| 摘要 |
PROBLEM TO BE SOLVED: To even segregation without soaking, decompose a degradation phase of a compound between metals to solidify it in a base, and eliminate bubbles and clearances by performing a hot isostatic compression at a temperature, preferably above a solid phase line but below a liquid phase line, before blooming forge or blooming roll is applied. SOLUTION: Hot isostatic compression is performed before an ingot is bloom- forged or bloom-rolled, where the ingot is picked up from an ingot case or a water cooling mold and the cast pieces obtained by cutting the ingot, flaws generated on the surface and the like are mended. The component composition of the ingot is optimum for a high alloy wherein segregation and degradation phases of the compound between metals become large. In a hot isostatic compression method, a material is pressurized and compressed with the isostatic pressure in a hot condition. A processing pressure is normally set to be 1,000-2,000 kgf/mm2 (90-180 MPa), and the time is 0.5-5 hours. It is preferable that an inert gas such as N2 and Ar, is used for pressurization.
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