A method for refining β grains of tc18 titanium alloy by step strain rate forging process

Abstract

The invention provides a method for refining β grains of TC18 titanium alloy by adopting step strain rate forging process. The method comprises the following steps: (1) heating the TC18 titanium alloy forging billet whose initial structure is a two-state structure to the forging temperature in the α+β dual-phase region, and keeping it warm until the temperature of the forging billet is uniform, and then performing two-stage step strain rate forging, The forging temperature is 700-820°C, the strain rate includes two stages, and the strain rate in the first stage is 0.1-0.5s ‑1 , the strain rate in the second stage is 1~5s ‑1 , the amount of deformation in the first stage is 20-40% of the height of the blank, the amount of deformation in the second stage is 30-50% of the height of the blank, the total deformation of the two stages is 50%-70%, and the strain after the deformation in the first stage is The rate changes immediately, without interval holding time; (2) After forging, immediately quench the forging. The invention can achieve the purpose of refining the beta grains of the TC18 titanium alloy with a relatively small amount of deformation.

Description

technical field [0001] The invention belongs to the technical field of forging, and relates to a method for refining beta grains of TC18 titanium alloy by adopting a step-strain rate forging process. Background technique [0002] TC18 titanium alloy is a near-beta titanium alloy, which combines the performance characteristics of α+β titanium alloy and β titanium alloy. It not only has excellent toughness, strength, damage tolerance, corrosion resistance and fatigue resistance, but also has good performance. The hardenability and other advantages. At present, near-beta titanium alloys are widely used in the production of aircraft landing gear, chassis, wings and other aviation parts. [0003] The properties of TC18 titanium alloy are closely related to its internal microstructure. Titanium alloys with dual-mode structure have better comprehensive properties and are generally obtained by forging in the α+β phase region. An important goal of forging in the α+β phase region is...

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Problems solved by technology

[0004] The purpose of the present invention is just to provide a kind of method that adopts the forging process of stepped strain rate to refine TC18 titanium alloy β grain, this method can effectively refine TC18 titanium alloy β grain with relatively small amount of deformation, solves the problem Existing methods for refining β grains of TC18 titanium alloy require multiple passes or repeated large deformations

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