JPS6411003A - Blooming method for high ni-fe alloy stock - Google Patents

Abstract

PURPOSE:To prevent generation of surface cracks and to reduce the rolling time by rolling a high Ni-Fe alloy stock containing a Ni component having a limited weight ratio by limiting a draft per pass and a finishing temp. after uniformly heating the stock at a limited temp. CONSTITUTION:A high Ni-Fe alloy stock containing a Ni component of 30-80% by wt. is uniformly heated at a temp. of <=1000 deg.C in a soaking-pit furnace and is rolled by a high draft of >=5% per pass; the rolling is completed at a finishing temp. of >=850 deg.C. The reason to uniformly heat at a bloom temp. of <=1000 deg.C is the high Ni-Fe alloy hardly generates intercrystalline cracks in that region. Blooming of the ingot soaked at a temp. of <=1000 deg.C is required to be completed at a temp. of >=850 deg.C not generating cracks caused by ductility reduction by increasing deformation resistance. Therefore, by blooming is performed by a strong draft of >=5% to reduce a temp. drop of the ingot during blooming. Hence, the rolling time is reduced and the productivity is improved without requiring reheating during rolling.