Stainless Steel Thread Galling: Root Causes & Anti-seize Protection Solutions
Thread galling, also known as metal seizing, is the most frequent failure issue when assembling A2 and A4 stainless steel fasteners. During tightening or disassembly, microscopic metal fusion occurs on thread surfaces, locking nuts completely and leading to bolt fracture when forced to unscrew. This defect severely troubles global engineering projects with high operating temperature, coastal humid environment and continuous mechanical vibration. Many contractors skip thread protection procedures, resulting in expensive rework and replacement costs for seized fastener joints.
1. Four Core Causes of Stainless Steel Thread Galling
- Lack of isolation layer: Identical stainless steel grades create molecular adhesion when metal surfaces rub against each other without separation medium
- Fast-speed tightening: Rapid nut rotation generates extreme friction heat, accelerating micro-welding of thread crests
- Surface contamination: Dust, oxide scale and metal debris act as abrasives, scratching the passive oxide film on threads
- Cyclic temperature fluctuation: Repeated heating and cooling destroys the thin anti-rust film, raising galling risk sharply
2. Comparison of Mainstream Anti-seize Compounds for Industrial Fasteners
| Anti-seize Product Type | Operating Temperature Range | Main Application Scenarios | Service Life |
| Copper Based Anti-seize Paste | -40℃ ~ 1100℃ | High-temperature pipelines, thermal power equipment | Up to 5 years |
| Food-grade Silicone Grease | -60℃ ~ 200℃ | Food processing machinery, indoor light assembly | 1–2 years |
| Molybdenum Disulfide Grease | -30℃ ~ 600℃ | Heavy machinery, vibration-intensive assemblies | 3–4 years |
| Permanent Ceramic Thread Coating | -70℃ ~ 1300℃ | Offshore marine facilities, chemical plants | Lifetime built-in protection |
3. Standard Assembly Guidelines for Stainless Fasteners
Pre-coated ceramic anti-seize stainless bolts are the most cost-effective long-term solution, eliminating the need for on-site lubrication during installation. If using copper paste manually, apply a thin layer only to thread teeth, avoid smearing the contact surface of washers and nuts. Conventional mineral oil lubricants are forbidden for high-temperature working assemblies, as they burn off under heat and lose anti-galling performance. Our factory supplies pre-treated ceramic coated stainless fasteners customized for global coastal, high-temperature and heavy-duty engineering projects.