HEAT TREATMENT FOR TI-6AL-4V ALLOY MATERIAL

摘要

PURPOSE:To make homogeneous the mechanical properties of a large-sized member, by working a Ti-6Al-4V alloy material in the alpha+beta area or beta area, thereafter subjecting the material to heat holding and controlled cooling under specific conditions and applying the same to an aging treatment. CONSTITUTION:The Al-6Al-4V alloyed material is worked by rolling, forging, hydrostatic pressing, etc., in the alpha+beta area of beta area and is thereafter held for 10min-8hr at 800-1,050 deg.C. Said material is continuously cooled little by little in succession to the range of 600-800 deg.C and is held for 10min-8hr at said temp. The material is then cooled to about =300 deg.C at the air-cooling ratio or cooling ratio over that, more specifically, at the cooling ratio of about =0.15 deg.C/sec. In succession to said cooling treatment, the aging treatment is applied to the material for 1-10hr at the temp. range of 450-650 deg.C. By this treatment, the alpha phase is deposited from the residual beta phase and the strength of the material is improved.