PRODUCTION OF TITANIUM ALLOY PART, TITANIUM ALLOY PART PRODUCED BY THIS PROCESS AND SEMI-FINISHED TITANIUM ALLOY PRODUCT

摘要

PURPOSE: To impart excellent strength and toughness to an alloy by quenching the alloy which is made into a metastable β structure by addition of a specific amt. of oxygen and nitrogen from a soln. heat treatment temp., then subjecting the alloy to an aging treatment, thereby forming a mixed structure of stable β and α'. ;CONSTITUTION: The metastable β titanium is first formed by adding 0.4 to 0.7% oxygen and 0.1 to 0.2% nitrogen to molten titanium in a range where the total of the oxygen and the nitrogen does not exceed 0.8% by weight ratio. After this molten metal is cast to form an ingot, the ingot is made into semi-finished products, such as rods or round rods, plates or sheet billet shapes, through rolling/forging. The semi-finished products are subjected to the soln. heat treatment at 800 to 900°C and are quenched at a cooling rate of ≥200°C/h, more preferably ≥400°C/h from this temp. The semi- finished products are thereafter subjected to forging, stamping or machining to the final shapes. In succession, the aging treatment for 550 to 650°C is executed for 10 minutes to 20 hours to transform the metastable β to form the stable β structure contg. 40 to 60% α'.;COPYRIGHT: (C)1995,JPO