| 摘要 |
PROBLEM TO BE SOLVED: To obtain a brass material with a fine crystal structure having high ductility to high speed external force and moreover excellent in strength, corrosion resistance and cuttability by subjecting a brass stock contg. a specified amt. of Zn to hot extrusion molding at a specified temp. and thereafter subjecting this brass extruded material to specified cooling. SOLUTION: A brass stock having 37 to 46 wt.% apparent Zn content is subjected to hot extrusion at 480 to 650 deg.C, desirably at about 480 to 600 deg.C, desirably at the reduction of cross-section of about >=90%. This brass extruded material is cooled to <=400 deg.C at a rate of >=0.4 K/sec after the hot extrusion. In this way, a brass member with a fine crystal structure having a crystal structure ofα+βat ordinary temp., in which the area ratio of theβphase is >=20%, desirably about 30 to 80%, and moreover, the average crystal grain size of theαphase andβphase is <=15μm is obtd. Thus, this member exhibits high ductility to high speed external force because of the dispersed generation of the strains of metallic crystals at the time of deformation in the case of being applied with external force and moreover obtains corrosion resistance, strength and cuttability based on theαphase andβphase. |
