Thread Lubricant For Fasteners: Full Classification, Selection Guide & Prohibited Application Scenarios
Thread lubricants serve two core functions during fastener assembly: reduce friction coefficient to achieve accurate rated tightening torque and prevent thread galling during later disassembly. Improper lubricant type or excessive coating is a major trigger for over-tightening bolt breakage, loose joints under temperature cycling and permanent sealing failure. Global engineering projects need to match lubricant formula according to operating temperature, working medium and fastener material (carbon steel / stainless steel).
1. Four Main Types Of Industrial Thread Lubricants
- Copper Anti-Seize Paste: Universal high-temperature compound, withstands continuous heat up to 1100℃, ideal for pipeline flange bolt joints
- Molybdenum Disulfide Grease: Forms solid wear-resistant film under continuous vibration, widely used for heavy machinery and automotive assembly
- Food-Grade Silicone Grease: Non-toxic formula compliant with food safety standards, allowed for food processing and pharmaceutical production equipment
- Graphite Dry Lubricant: Cost-effective choice for dry high-temperature mechanical joints without water contact
2. Temperature Range & Application Restriction Comparison Table
| Lubricant Type | Operating Temperature Range | Strictly Forbidden Working Scenarios |
| Copper Anti-Seize Paste | -40℃ ~ +1100℃ | Precision electronic devices (conductive metal particles cause short circuit) |
| Molybdenum Grease | -30℃ ~ +600℃ | Food and beverage production lines (contains toxic heavy metal additives) |
| Food-Grade Silicone Grease | -60℃ ~ +200℃ | High-temperature equipment operating over 200℃ continuous heat |
| Dry Graphite Lubricant | -20℃ ~ +800℃ | Humid coastal and underwater marine facilities |
3. Severe Assembly Mistakes With Thread Lubricants
The most dangerous error is smearing lubricant on washer and nut bearing surfaces instead of only thread teeth. It eliminates friction resistance on contact planes, leads to unstable clamping force and spontaneous nut loosening under vibration. The second frequent mistake: no torque reduction after applying lubricant — lubricant cuts friction force by 30%–50%, standard dry torque value will overstress and crack bolt shafts. Third mistake: applying conductive copper/molybdenum paste on food-grade medical processing equipment. Our engineering team provides customized lubricant matching schemes and adjusted torque reference charts for all bulk fastener export orders.