MANUFACTURE OF BORON-CONTAINING AUSTENITIC STAINLESS STEEL HAVING EXCELLENT HOT WORKABILITY AS WELL AS COLD DUCTILITY AND TOUGHNESS

摘要

PURPOSE:To obtain the B-contg. SUS steel for a spent nuclear fuel caster having excellent hot workability as well as cold ductility and toughness by forming the atomizing powder of a steel having prescribed componental compsn. into a billet by high temp.-high pressure hot isostatic pressing and thereafter executing hot rolling. CONSTITUTION:Atomizing powder contg., by weight, 0.3 to 3.0% B, =0.08% C, 0.01 to 2.0% Si, =2.0% Mn, 16.0 to 20.0% Cr, 8.0 to 15.0% Ni, =3.0% Mo and the balance substantial Fe and having the grain size finner than 20 mesh is prepd. The above powder can be obtd. by flowing a molten steel from fine pores, blowing high pressure water, gas, oil or the like over the molten steel flow and rapidly solidifying the molten steel into the shape of powder. Next, the above atomizing powder having the grain size finner than 20 mesh is subjected to hot isostatic pressing under the conditions of 1000 to 1250 deg.CX=800 kg/cm2 pressure to form into a billet. Then, the formed body is subjected to hot rolling, by which the objective boron-contg. austenitic stainless steel having excellent hot workability as well as cold ductility and toughness can be obtd.