MANUFACTURING AUTHORISATION HOLDER RESPONSIBLE FOR BATCH RELEASES

摘要

The present invention provides an improved process for fabricating shaped articles from high strength, low ductility nickel base alloys, especially modified IN100. According to the process, the alloy in prealloyed powdered form is hot isostatically pressed to provide a homogeneous, solid billet. The pressed, low ductility billet is then isothermally forged to shape in hot dies in a single forging pass which includes an initial slow strain rate stage to effect a minor reduction in thickness sufficient to refine the alloy grain structure and place the billet in a temporary condition of low strength and high ductility followed by a high strain rate stage for effecting a major reduction in thickness to the final desired shape while the billet is in said temporary condition. In the initial slow strain rate stage, the strain rate is selected in relation to the isothermal forging temperature such that the rate is sufficiently slow to prevent cracking of the alloy billet during the initial minor reduction. In the high strain rate stage, the strain rate employed is generally significantly higher than that used in the initial stage to assure attainment of desirable mechanical properties in the heat treated article.