Methods for Preventing Seizure of Stainless Steel Fasteners

Release date:

2021-10-26

Author:

Fasteners are commonly referred to as standard parts in the market; they constitute a broad category of mechanical components used to securely join two or more parts (or structural elements) into a single, integrated assembly. They are characterized by an extensive variety of types and specifications, diverse performance and applications, and a high degree of standardization, serialization, and interchangeability. As widely used basic mechanical components, fasteners enjoy substantial demand.
Steps/Methods
1. Select the product correctly: Before use, verify that the product’s mechanical properties meet your application requirements, such as the screw’s tensile strength and the nut’s proof load. Choose an appropriate screw length, ensuring that after tightening, 1–2 thread pitches remain exposed beyond the nut.
2. Before use, inspect the threads for roughness and check between the threads for metal filings or debris, as these can often cause the fastener to seize.
3. Before use, the fasteners can be lubricated: it is recommended to use grease, molybdenum disulfide, mica, graphite, or talcum powder as lubricants. Currently, wax impregnation is widely employed for lubrication and to prevent seizing.
4. Pay attention to the method of use:
a. The speed and force applied during screwing-in should be moderate—avoid excessive speed or torque. Whenever possible, use a torque wrench or socket wrench; refrain from using an adjustable wrench or an electric wrench. Excessive speed can cause a rapid temperature rise, leading to seizing. Imported pump valves.
b. The direction of the applied force: the nut is screwed on perpendicular to the screw’s axis.
5. Using washers can effectively prevent the issue of over-tightening during locking.
6. Seizing or galling frequently occurs with fasteners made of stainless steel, aluminum alloys, and titanium alloys. These metallic alloys possess inherent corrosion‑resistant properties; when their surfaces are damaged, a thin oxide layer forms to prevent further corrosion. However, when a stainless‑steel fastener is tightened, the pressure and heat generated between the threads can disrupt this oxide layer, leading to blockage or shearing of the metal threads and subsequent adhesive wear. If this process continues, the stainless‑steel fastener may become completely seized, rendering it impossible to remove or re‑tighten. Typically, this sequence of blocking, shearing, adhesion, and seizing unfolds within just a few seconds. Therefore, proper understanding and correct handling of such fasteners are essential to prevent this phenomenon.