High-temperature nitriding ultrafine deformation control method of thin-walled dual-shell titanium alloy bushing

Abstract

The invention belongs to the technical field of metal heat treatment, and relates to a high-temperature nitriding ultrafine deformation control method of a thin-walled dual-shell titanium alloy bushing. According to the high-temperature nitriding ultrafine deformation control method of the thin-walled dual-shell titanium alloy bushing, a titanium alloy ion nitriding furnace with an auxiliary heatsource is used, isoelectric potential local negative glow area space is built with the aid of an auxiliary cathode cylinder-shaped tool, and a hollow cathode effect between double shells is eradicatedcompletely by adopting mechanical shielding; and by a way of overlapping geometric centers of parts, the tool and an effective working area in the ion nitriding furnace, step-type temperature rise, heat preservation and temperature reduction with 300 DEG C-450 DEG C and 500 DEG C-650 DEG C are adopted when ion nitriding is carried out, temperature preservation time is 2-4 hours after the temperature is reached, the rate of heating up and cooling is controlled at 0.5-4 DEG C/min, high temperature annealing with 850 DEG C-950 DEG C is carried out before the nitriding is carried out, a glow heating system is started when the temperature is raised to 300 DEG C-400 DEG C, and nitriding is carried out for 6-20 hours at 750 DEG C-880 DEG C. By comprehensive application of the means, the high-temperature ion nitriding deformation ultrafine control over titanium alloy bushing parts with thin-walled dual-shell complex structures is achieved, and the deformation amount is less than or equal to 0.020mm.

Description

technical field [0001] The invention belongs to the technical field of metal heat treatment, and relates to a high-temperature nitriding ultra-precision deformation control method of a thin-walled double-shell titanium alloy bushing. Background technique [0002] Due to the strong chemical affinity between titanium and oxygen and nitrogen, high-temperature ion nitriding can only be used for titanium alloy nitriding. The in-situ binding with the matrix titanium atoms improves the nitriding rate. The thermal conductivity of titanium alloy is low. During the heating process, the internal and external temperature rise of the part is inconsistent, which leads to serious deformation when it is nitrided at a high temperature above 750 ° C, especially the double-shell titanium alloy bushing with thin effective wall thickness and extremely complex structure. , after the ion nitriding is completed, the ellipse deformation needs to be controlled within 0.020mm. According to relevant l...

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Problems solved by technology

The thermal conductivity of titanium alloy is low. During the heating process, the internal and external temperature rise of the part is inconsistent, which leads to serious deformation when it is nitrided at a high temperature above 750 ° C, especially the double-shell titanium alloy bushing with thin effective wall thickness and extremely complex structure. , after the ion nitriding is completed, the ellipse deformation needs to be controlled within 0.020mm. According to relevant literature and data retrieval, the current existing technology cannot meet this technical requirement.

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