钛合金螺栓与自锁螺母咬死故障原因分析

某型号用TB3钛合金螺栓与TB3钛合金自锁螺母在拆卸过程中发现相互咬死,取故障批螺栓与故障批自锁螺母进行重复装配试验,均发生咬死故障。通过对故障影响因素排查与验证试验,对故障螺栓进行了形貌观察及金相分析,并对比研究了3种不同工艺生产的螺栓。结果表明:螺栓涂覆MoS2之前缺失喷砂处理,使螺栓基体表面MoS2涂层的厚度减小、附着力显著降低,从而严重降低了MoS2涂层的润滑作用,导致螺栓螺齿基体与螺母螺齿基体裸露并发生粘着磨损,致使螺齿发生塑性变形,出现咬死故障。

Analysis on Jamming Failure between Titanium Alloy Bolt and Self-locking Nut

A jamming fault arose during the assembly process between a titanium alloy bolt （TB3） and a self-locking nut （TB3）. Through repeated assemblies, the fault still existed. Factors of the failure were analyzed and verification experiments were carried out; morphological observation and metallographic structure examination were performed; three types of bolts produced through different technology were compared. The results show that if the bolts have not been blasted before coating, the thickness and adhesion capability of MoS2 coating decrease obviously and MoS2 coating loses its lubrication prematurely. It makes the thread tooth base of holt and nut naked and then adhesive wear occurs. As a result, thread teeth plastically deform, leading to a jamming fault.