A.Core application scenarios of the anti-tension firmware
1. Bridges and transportation
Bridge: frequent vibration (anti-loosening and anti-stripping to ensure the stability of the bridge)
Engine system: cylinder head bolts, crankshaft bolts (withstand high frequency vibration)
Chassis components: suspension bolts (anti-loosening and anti-tripping to ensure driving safety)
Wheel hub fixing: truck tire nut (double nut locking structure)
Transportation track: high-speed rail fasteners (fatigue life >10^8 cycles)
2. Construction machinery and heavy equipment
Track connection: excavator track bolt (impact load >5000N·m)
Hydraulic cylinder system: Prevent decylinder accidents caused by piston movement (wear protection)
Steel structure connection: heavy-duty high-strength bolts (grade 12.9 and above, material 4140)
3. Energy and Industrial equipment
Wind power tower: large diameter bolts above M36 (preload control ±5%)
Oil pipeline: API 6A standard anti-vibration flange bolts
Nuclear power facilities: anti-loose + anti-corrosion integrated design
Bridge: Embedded large nuts that sink to the sea floor and lock the bridge columns
Industry standard: EN 14399 (Steel structure)
4. Four categories of anti-tension firmware
4.1 Friction locking
Nylon Lock Nut (NYLOC)
Suitable for high pressure cylinder and gearbox locking buffer field, high temperature environment (up to 300℃)
4.2 Mechanical locking type
Two-nut system (Junker Test passed.
Cotter pin + slotted nut used in aviation (ANSI B18.2.2)
4.3 Butterfly self-locking Washer (Belleville Washer/Conical Spring Washer)
Cone disc design (standard cone Angle 15°-30°)
Serrated bite design
Material thickness to diameter ratio: 1:10 ~ 1:20
Common materials:
Carbon steel (SAE 1074, hardness HRC 42-50) + Dacromet
Stainless steel (AISI 301/316, Corrosion resistance Class C4)
4.4 Special structural type
Hydraulic tension bolt (SKF Triboloc)
Accuracy of preloading force ±1%
Shape memory alloy washer (temperature trigger locking)
5. The core role of anti-tension firmware
4.1 Stability under vibration
Reduce the probability of loosening from 17% of traditional fasteners to less than 0.5% (VDI 2230 standard)
4.2 Preload maintenance
Comparison of preload retention rate after 2 million vibrations:
Common nut: ≤40%
Lock nut: ≥85%
6. Manufacturing method of nuts and bolts
Advantages:
The grain flow direction is consistent with the force direction, the strength is increased by 20%, and the batch cost is low.
Surface finish Ra 1.6-3.2μm
1.2 Hot Forging
Application scenario:
Large size bolts (above M27)
Can be applied to high strength special alloys
Process parameters:
Heating temperature: 1050-1250℃ (carbon steel)
Forging pressure: 200-800 tons
Hot Forging
Application scenario:
Large size bolts (above M27)
Can be applied to high strength special alloys
Process parameters:
Heating temperature: 1050-1250℃ (carbon steel)
Forging pressure: 200-800 tons
Machining
Scope of application:
Non-standard shaped parts
Small batch precision parts (Aviation fasteners)
Finished parts after hot forging
Powder Metallurgy (PM)
Special Application:
Oil self lubricating nut
Surface treatment of nuts and bolts
Electroplating process
Ultrasonic cleaning is required before plating (to remove processing grease)
Hydrogen embrittlement after plating (200℃×4h, ISO 9587)
Hot Dip Galvanizing (HDG)
Process features:
Coating thickness 50-100μm
Salt spray resistance > 1000 hoursApplicable products:
Wind power tower bolt
Stadium/airport structural connector
Dacromet
Coating composition:
Zinc powder + aluminum sheet + chromate
Outstanding advantages:
Corrosion resistance 1000+ hours, no risk of hydrogen embrittlement
High temperature resistance (300℃ short-term)
Typical applications:
Car chassis bolt
Bridge high speed rail fastening system
Oxidation treatment
Blackening treatment:
Film thickness 0.5-1.5μm
Easy to scratch, salt spray time is short
Phosphating treatment:
Improve coating adhesion, salt spray time in 48-72 hours
Zinc/manganese phosphating is commonly used
New surface technologies
PVD coating:
Titanium nitride (TiN) coating, hardness HV2000+
Suitable for drive threads that require wear resistance
Laser cladding:
The wear resistant alloy is coated locally in the screw
Used for strengthening special parts of oil drilling tools
Technical Advice:
For the Butterfly Washer Selection Manual or a custom non-standard (locking) nut solution, please contact our application engineers.
