Shape memory alloy check nut and manufacturing technique

Abstract

The invention relates to a shape memory alloy blocking nut and its preparing process. The raw materials for the nut comprise the following components(in % by weight): C 0.01-0.05, Mn 15.0-17.0, Si 4.8-5.2, Cr8.5-9.5, Ni 6.5-7.5, P 0.01-0.03, S 0.01-0.02, N 0.03-0.05, and Fe 60.65-65.05. The preparing process comprises: (1) preparing the raw materials and rolling to obtain the iron-base shape memory alloy rod stocks with outside hexagon strip and inner circular hole; (2) solution treatment for the rod stocks: keeping the temperature of 950K. to 1150K. for 30 min to 60 min; (3) shape memory training for the rod stocks; (4) cutting the rod stocks to nut blanks, and processing the inner circular hole according to the given size of 94% to 96%; (5) reaming the nut to given size for completing the stress induced martensitic transformation of the nut; (6) fine machining for the internal thread; (7) pre-tightening the nut according to the estimated force moment, keeping the temperature of 500K to 800K for 15min to 45min, and carrying out the annealing treatment.

Description

technical field [0001] The invention relates to a shape memory alloy anti-loosening nut and a production process thereof. technical background [0002] Screw connection is one of the commonly used connection methods for modern structures and mechanical equipment. Generally, threaded connections have self-locking properties, but when subjected to variable loads, vibrations, impacts, or large temperature changes, threaded connections are prone to loosening, resulting in a decrease in pre-tightening force. The use of threaded connections and anti-loosening performance experiments, fatigue The strength test proves that loosening failure is one of the main failure modes of threaded connections subjected to alternating loads. Loosening will cause the reduction or even loss of the pre-tightening force of the connection, thereby reducing the quality of the threaded connection and causing premature failure of the connected parts. Even cause equipment failure and personal accidents. ...

AI Technical Summary

Problems solved by technology

Generally, threaded connections have self-locking properties, but when subjected to variable loads, vibrations, impacts, or large temperature changes, threaded connections are prone to loosening, resulting in a decrease in pre-tightening force. The use of threaded connections and anti-loosening performance experiments, fatigue The strength test proves that loosening failure is one of the main failure modes of threaded connections subjected to alternating loads. Loosening will cause the reduction or even loss of the pre-tightening force of the connection, thereby reducing the quality of the threaded connection and causing premature failure of the connected parts. Even cause equipment failure and personal accidents. In recent years, scientific and technological workers at home and abroad have conducted a lot of research on the anti-loosening of threaded connections, and proposed some anti-loosening technologies and measures, and achieved certain results. However, the reliability of these measures Poor, complex structure, and sometimes even change the detachable nature of the connection, so the problem of loosening of the threaded connection has not been fundamentally solved