DIN 933 Sechskantschrauben mit Zink-Nickel-Beschichtung
DIN 933 Zinc-Nickel Plated Hex Bolts
DIN 933 hex bolts with zinc-nickel (Zn-Ni 12–15%) plating provide enhanced corrosion resistance for automotive, industrial, and harsh environment applications requiring standardized full-thread fastening solutions.
Why DIN 933 with Zinc-Nickel (Zink-Nickel Beschichtung)?
DIN 933 specifies full-threaded hexagon head bolts (Sechskantschrauben mit Vollgewinde). When combined with zinc-nickel electroplating (Zink-Nickel-Beschichtung), these bolts feature a coating typically containing 12–15% nickel in the zinc-nickel alloy layer. This composition provides superior corrosion protection (Korrosionsschutz) compared to standard zinc plating.
Zinc-nickel plating is commonly selected for DIN 933 bolts when enhanced corrosion resistance is required, particularly for outdoor applications, solar installations, and automotive use where VDA 233-102 compliance is referenced.
The zinc-nickel coating is applied via electroplating process, forming a uniform layer over the bolt surface. The coating thickness and composition affect corrosion performance, which depends on coating system and test conditions.
DIN 933 zinc-nickel plated bolts are technically equivalent to ISO 4017 bolts with the same coating specification, ensuring international compatibility in technical documentation and procurement.
Salt Spray Performance (Salzsprühnebel)
Zinc-nickel plated DIN 933 bolts typically achieve 720–1000+ hours salt spray resistance (Salzsprühnebel 720h / 1000h) per ISO 9227 or ASTM B117 standards. Performance depends on coating system and test conditions. This significantly exceeds standard zinc plating (typically 72–240h) and is suitable for harsh outdoor environments.
Application Suitability
- •Solar / Outdoor Applications – Suitable for PV installations, ground mount systems, and outdoor structures requiring long-term corrosion protection.
- •Automotive Applications – Commonly referenced in VDA 233-102 automotive testing standards. Performance depends on coating thickness, composition, and test conditions.
ISO 19598 Compliance
Zinc-nickel plated DIN 933 bolts comply with ISO 19598 standard, which specifies requirements for zinc-nickel electroplated coatings on fasteners. The standard covers coating composition (10-15% Ni), thickness (8-15 μm), and corrosion performance requirements. Cr(VI)-free passivation (Cr(III)) ensures RoHS compliance.
Typical Reasons to Choose Zinc-Nickel Plating
- •Enhanced Corrosion Resistance – Zinc-nickel coatings typically provide higher salt spray performance compared to standard zinc plating, making them suitable for automotive and harsh environment applications.
- •Automotive Compatibility – Commonly referenced in VDA 233-102 automotive testing standards. Performance depends on coating thickness and test conditions.
- •Uniform Coating Thickness – Electroplating process ensures consistent coverage across bolt surfaces, including threads and head areas.
- •RoHS Compliance – Zinc-nickel plating is RoHS compliant, suitable for applications requiring environmental compliance.
Finish Options
DIN 933 zinc-nickel plated bolts are available in different finish options to meet application requirements:
- •Clear (Silver) Finish – Standard zinc-nickel appearance without additional treatment. Provides typical corrosion protection.
- •Black Passivated Finish – Additional passivation treatment creates a black appearance. May affect corrosion performance depending on passivation chemistry.
Coating Options vs Typical Use
| Coating Option | Typical Use | Notes |
|---|---|---|
| Zinc-Nickel (Clear) | Automotive assemblies, industrial equipment | Standard finish, commonly referenced in VDA 233-102 |
| Zinc-Nickel (Black) | Aesthetic applications, visible assemblies | Passivation treatment may affect corrosion performance |
| Zinc Flake (Alternative) | High corrosion resistance, no hydrogen embrittlement | Alternative coating system without hydrogen embrittlement concerns |
General Considerations
Hydrogen Embrittlement
Electroplated zinc-nickel coatings may introduce hydrogen into the bolt material during the plating process. For high-strength bolts (grade 10.9 and above), post-plating baking is commonly used to reduce hydrogen embrittlement risk. Baking parameters typically range from 200°C for 4–8 hours, depending on bolt grade and application requirements.
Zinc Flake Alternative
Zinc flake coatings offer an alternative surface treatment for DIN 933 bolts without hydrogen embrittlement concerns. These coatings are applied via mechanical application and curing, providing high salt spray performance suitable for automotive and industrial applications.
Testing Standards
Corrosion performance is commonly evaluated using ISO 9227 (salt spray test) and VDA 233-102 (automotive standard). Performance depends on coating system and test conditions. Specific salt spray hours vary based on coating thickness, composition, and test parameters.
Engineering Support
Engineering drawings, material certificates, and coating specifications are available for technical evaluation upon request.
Frequently Asked Questions
What is zinc-nickel plating on DIN 933 bolts?
Zinc-nickel (Zn-Ni) plating is an electroplated coating typically containing 12–15% nickel, applied to DIN 933 hex bolts. It provides enhanced corrosion resistance compared to standard zinc plating, making it suitable for automotive and harsh environment applications.
Is zinc-nickel plating compatible with VDA 233-102?
Zinc-nickel coatings are commonly referenced in VDA 233-102 automotive testing standards. Performance depends on coating thickness, composition, and test conditions. Specific compliance should be verified with material certificates.
What finish options are available for zinc-nickel plated DIN 933 bolts?
Zinc-nickel plated DIN 933 bolts are typically available in clear (silver) or black passivated finishes. Clear finish provides standard appearance, while black passivation offers additional aesthetic options for specific applications.
Does zinc-nickel plating cause hydrogen embrittlement?
Electroplated zinc-nickel coatings may introduce hydrogen during the plating process. Post-plating baking (typically 200°C for 4–8 hours) is commonly used to reduce hydrogen embrittlement risk. Zinc flake coatings offer an alternative without hydrogen embrittlement concerns.
When should I choose zinc-nickel over standard zinc plating for DIN 933 bolts?
Zinc-nickel plating is recommended when higher corrosion resistance is required, such as automotive applications, coastal environments, or industrial equipment exposed to harsh conditions. Performance depends on coating system and test conditions.
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