JGD® Fasteners — A Global Provider of Industrial Connection Safety Solutions
Anti-loosening / Anti-fatigue / Corrosion resistant / Full traceability, providing a solid safety foundation for critical equipment.
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Anti-loosening and Vibration Resistance Solutions
Core Value: Designed for dynamic loads and vibration conditions, ensuring connections never loosen.
Technical Highlights:
• Nylon Anti-loosening: Reusable, suitable for low to medium vibration.
• All-metal Locking: Preferred for high-temperature conditions, highest vibration resistance rating.
• Pre-applied Threadlocker: Pre-assembled design, zero errors on-site.
Verification Standards: Meets DIN 65151 / ISO 16130 lateral vibration test standards.
| Locking Type | Technical Principle | Applicable Working Conditions | Reusability | Temperature Range | Vibration Resistance Rating | Recommended Strength Grade |
| Nylon Locking (Nylon Insert) | Friction generated by extrusion between nylon ring and threads | Medium-low vibration, normal temperature | ✅ Reusable 3-5 times | -50°C ~ +120°C | ★★★☆☆ | Grade 8.8 ~ 12.9 |
| All-Metal Locking (Non-Metal Insert Free) | Radial clamping force generated by local thread deformation | High-temperature conditions, high vibration | ✅ Reusable | -50°C ~ +300°C | ★★★★☆ | Grade 8.8 ~ 12.9 |
| Pre-Applied Threadlocker | Microcapsule coating, broken and cured during assembly | Mass assembly, anti-missing installation | ❌ Single-use only | -50°C ~ +150°C | ★★★★★ | Grade 8.8 ~ 10.9 |
| Flange Face Bolt | Flange face serrations embedded into the mating surface | Medium-high vibration, compatible with soft materials | ✅ Reusable | Unlimited | ★★★☆☆ | Grade 8.8 ~ 12.9 |
| Serrated Thread (Spiralock) | 30° wedge ramp changes load distribution | Extreme vibration, aerospace grade | ✅ Reusable | Unlimited | ★★★★★ | Grade 10.9 and above |
Test Standard Description:
• Vibration Test: Based on DIN 65151 or ISO 16130 transverse vibration test standard.
• Anti-loosening Performance Evaluation: Measured by the percentage of residual clamping force; ≥80% is considered excellent.
Corrosion Protection and Environmental Resistance Solutions
Core Value: Providing full lifecycle corrosion protection for harsh working conditions
Technical Highlights:
• Zinc-aluminum coating (Dacromet/Gumite): No hydrogen embrittlement risk, salt spray resistance up to 1000 hours or more
• Hot-dip galvanizing: Suitable for large structural components, excellent outdoor weather resistance
• Stainless steel options: A2/A4/A5 materials, suitable for highly corrosive environments such as marine and chemical plants
• Composite coating system: Base layer corrosion protection + top layer lubrication, balancing protection and assembly stability
Verification standards: Based on ISO 9227 neutral salt spray test, providing corrosion resistance certification
| Surface Treatment Type | Technical Principle | Neutral Salt Spray Resistance Hours | Coating Thickness | Operating Temperature Range | Hydrogen Embrittlement Risk | Typical Application Scenarios |
| Zinc-Aluminum Coating (Dacromet/Geomet) | Flake zinc-aluminum powder + chromate/chromium-free binder, multi-layer coating and baking | 480 ~ 1500+ hours | 5 ~ 15 μm | -50°C ~ +300°C | None | Automotive chassis, wind power bolts, high-strength fasteners |
| Hot-Dip Galvanizing | Bolts immersed in molten zinc to form zinc-iron alloy layer + pure zinc layer | 500 ~ 1000 hours | 40 ~ 100 μm | -50°C ~ +200°C | Low (hydrogen relief required) | Power towers, bridges, large steel structures |
| Mechanical Galvanizing | Zinc powder deposited on surface via mechanical impact, no electrochemical process | 100 ~ 300 hours | 10 ~ 50 μm | -50°C ~ +100°C | None | High-strength fasteners, construction hardware |
| Electro-Galvanizing (Yellow Zinc/Blue Zinc/White Zinc) | Electrochemical zinc deposition with passivation treatment | 72 ~ 240 hours (depending on passivation layer) | 5 ~ 15 μm | -50°C ~ +120°C | High (hydrogen relief required) | General industry, home appliances, medium/low-strength fasteners |
| Stainless Steel (A2/A4/A5) | Corrosion resistance from material itself, no coating required | 2000+ hours (no salt spray failure) | Not applicable | -200°C ~ +800°C | None | Marine engineering, chemical equipment, food machinery |
| Composite Coating (Zinc-Aluminum + Topcoat) | Base layer anti-corrosion + top layer lubrication/coloring | 720 ~ 1500+ hours | 10 ~ 25 μm | -50°C ~ +250°C | None | Automotive powertrain, high-requirement appearance parts |
Key Notes:
• Salt spray resistance hours are based on the ISO 9227 neutral salt spray test, with the time to white rust appearance as the criterion.
• Coating thickness is positively correlated with corrosion resistance, but thread clearance must be considered.
• For high-strength fasteners (grade 10.9 and above), it is recommended to choose a surface treatment without hydrogen embrittlement risk.
Hydrogen Embrittlement Resistance and High-Strength Application Solutions
Core Value: Providing Zero-Risk Protection for High-Strength Fasteners
Technical Highlights:
• Low Hydrogen Embrittlement Process: The electroplating process employs low-hydrogen embrittlement zinc plating technology, with strict control over current density and plating solution composition.
• Hydrogen Removal Treatment: Hydrogen removal is performed within 4 hours after electroplating (above 200°C, ≥8 hours) to ensure sufficient hydrogen atom escape.
• Process Monitoring: Hydrogen embrittlement testing (parallel notch tensile test or continuous load test) is conducted on each batch.
• Materials Selection: For grade 10.9 and above, non-electroplating surface treatments (such as zinc-aluminum coating, mechanical galvanizing) are recommended.
Validation Standards: ISO 15330 / ASTM F519 Hydrogen Embrittlement Sensitivity Testing
| High Strength Grade | Hydrogen Embrittlement Risk Level | Recommended Surface Treatments | High-Risk Surface Treatments (Strict Control Required) | Hydrogen Embrittlement Relief Process Requirements | Hydrogen Embrittlement Testing Method |
| Grade 8.8 | Low Risk | Electro-galvanizing, Zinc-aluminum Coating, Mechanical Galvanizing | No Special Restrictions | Hydrogen relief within 4 hours after electroplating (190-210°C, ≥4h) | Optional |
| Grade 10.9 | Medium-High Risk | Zinc-aluminum Coating, Mechanical Galvanizing, Phosphating, Dacromet | Electro-galvanizing (Requires strict hydrogen relief + process control) | Hydrogen relief within 2 hours after electroplating (200-220°C, ≥8h) | Recommended for each batch |
| Grade 12.9 | High Risk | Zinc-aluminum Coating, Mechanical Galvanizing, Geomet, Phosphating + Oil | Electro-galvanizing not recommended | If electroplating is mandatory, special process + hydrogen relief (220-240°C, ≥12h) + 100% inspection | Mandatory for each batch |
| Above Grade 12.9 / SCM435 | Extremely High Risk | Only non-electroplating treatments allowed: Zinc-aluminum Coating, Dacromet, Geomet, Blackening | Electro-galvanizing strictly prohibited | Electroplating process not applicable | 100% hydrogen embrittlement test + process monitoring |
Hydrogen embrittlement testing standards:
• Sustained load test: According to ISO 15330 or ASTM F519, maintain stress for more than 200 hours and observe for fracture.
• Parallel notch tensile test: According to ASTM F606, compare the tensile properties of hydrogen-containing and hydrogen-free specimens.
Key process control points:
• Pretreatment: Control pickling time, add corrosion inhibitors to avoid excessive hydrogen evolution.
• Electroplating process: Control current density, select a low-hydrogen-embrittlement plating solution system.
• Hydrogen removal treatment: Performed within 4 hours after electroplating, with strict temperature and time control and recording.
• Batch traceability: Record the hydrogen removal furnace temperature curve for each batch and archive for future reference.
Failure Analysis and Technical Support
Core Value: Learn from failures and continuously optimize connection design
Technical Highlights:
• Failure Database: Over a thousand fastener failure cases (fatigue, overload, hydrogen embrittlement, corrosion, loosening, etc.)
• Professional Testing Capabilities: Fracture surface scanning electron microscopy analysis, metallographic examination, chemical composition analysis, hardness gradient testing
• Root Cause Tracing: Combining production process records to pinpoint the root cause of failure (materials, processes, assembly, design, operating conditions)
• Improvement Output: Providing a written failure analysis report, including root causes and preventative improvement recommendations
| Analysis Item | Testing Method | Applicable Standards | Analysis Scope | Typical Detection Information |
| Fracture Morphology Analysis | Stereomicroscope / Scanning Electron Microscope (SEM) | ISO 18434, ASTM E2328 | Fatigue fracture, overload fracture, hydrogen embrittlement fracture, stress corrosion fracture | Fatigue striations, dimples, intergranular fracture, cleavage fracture |
| Chemical Composition Analysis | Optical Emission Spectrometer (OES) / Carbon-Sulfur Analyzer | ISO 14284, ASTM E415 | Low-alloy steel, stainless steel, carbon steel fasteners | Content of carbon, silicon, manganese, phosphorus, sulfur and alloy elements |
| Metallographic Structure Analysis | Optical Microscope / Image Analysis System | ISO 643, ASTM E3, GB/T 13298 | Grain size, decarburized layer, non-metallic inclusions, tempered structure | Grain size grade, decarburization depth, inclusion type (A/B/C/D) |
| Hardness Test | Rockwell / Vickers / Brinell Hardness Tester | ISO 6506/6507/6508, ASTM E18/E10 | Surface hardness, core hardness, hardness gradient | Hardness values HRC/HV/HB, to evaluate heat treatment quality |
| Hydrogen Embrittlement Susceptibility Test | Sustained Load Test / Notched Tensile Test | ISO 15330, ASTM F519 | Hydrogen embrittlement risk of high-strength bolts after electroplating | No fracture in 200 hours (qualified) / Early fracture (unqualified) |
| Torque-Clamp Force Test | Torque-Clamp Force Test Bench | ISO 16047, GB/T 16823.2 | Torque coefficient K, friction coefficient μ | K value range, μ_th, μ_b |
| Salt Spray Corrosion Test | Neutral Salt Spray Chamber | ISO 9227, ASTM B117 | Corrosion resistance of surface treatments | Time to appearance of white rust/red rust |
| Residual Stress Analysis | X-ray Diffraction Method / Hole Drilling Method | ASTM E837 | Surface residual compressive stress/tensile stress | Residual stress value (MPa), to evaluate shot peening effect |
JGD® Helps You Start Your Fastener Success Journey
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Frequently Asked Questions
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Do you support custom and non-standard fasteners?+ -Yes. We specialize in non-standard fasteners manufactured according to drawings, samples, or technical requirements, with tolerance control applied.
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Can you supply mixed fasteners based on a BOM or item list?+ -Yes. We are experienced in handling mixed fastener lists for engineering and project orders.Different items can be combined in one order and one shipment.
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Do you accept small or medium batch orders?+ -Yes. We support prototype, small and medium batch production, especially for custom and non-standard fasteners.
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How do you ensure quality for mixed and custom orders?+ -Each item is inspected during production and before packing.Our quality system ensures accuracy and consistency for mixed fastener orders.
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Do you provide material certificates or inspection records?+ -Yes. Material certificates and inspection records are available upon request. Our quality system is ISO 9001 certified.
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How soon can you respond after receiving our list or drawings?+ -We usually respond with technical feedback or quotation within 24 hours after receiving your information.
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