Extreme Corrosion Resistance for Harsh Environments
Hot dip galvanized DIN933 hex bolts, ASTM490 nuts and washers provide the highest level of corrosion protection available for steel fasteners. The hot dip galvanizing process creates a thick, durable zinc-iron alloy coating that offers superior protection against rust, corrosion, and environmental degradation.
These fastener sets are manufactured to meet both DIN933 (German) and ASTM490 (American) standards, ensuring international compliance and quality. Available in high-strength grades 8.8, 10.9, and 12.9, they combine exceptional mechanical properties with unmatched corrosion resistance.
Extreme Corrosion Resistance
Hot dip galvanizing provides 3-4 times thicker coating than electroplating, offering superior protection in harsh environments.
High Strength Grades
Available in 8.8, 10.9, and 12.9 strength grades to withstand heavy loads and structural stresses.
Complete Weather Protection
Ideal for outdoor applications, marine environments, and areas with high humidity or chemical exposure.
International Standards
Compliant with DIN933, ASTM490, and ISO 1461 standards for global acceptance and quality assurance.
Strength Grade Specifications
Select the appropriate strength grade based on your application requirements, load conditions, and environmental factors.
Grade 8.8 – Medium Carbon Steel, Quenched & Tempered
Grade 8.8 is the most commonly used high-strength bolt grade, offering an excellent balance between strength, ductility, and cost-effectiveness. These bolts are suitable for general structural applications where high strength is required.
| Property | Specification | Application Benefit |
|---|---|---|
| Material | Medium Carbon Steel (Quenched & Tempered) | Good strength with reasonable ductility |
| Tensile Strength | 800 MPa (116,000 psi) min | High load-bearing capacity |
| Yield Strength | 640 MPa (93,000 psi) min | Good resistance to permanent deformation |
| Elongation | 12% min | Adequate ductility for most applications |
| Hardness | HRC 22-32 | Balanced hardness for strength and toughness |
| Primary Applications | General construction, machinery, automotive, structural steel connections, equipment assembly | |
Grade 10.9 – Alloy Steel, Quenched & Tempered
Grade 10.9 bolts are made from alloy steel and offer higher strength than Grade 8.8. They are used in applications where higher clamping forces or resistance to dynamic loads are required.
| Property | Specification | Application Benefit |
|---|---|---|
| Material | Alloy Steel (Quenched & Tempered) | Higher strength than carbon steel |
| Tensile Strength | 1000 MPa (145,000 psi) min | Very high load-bearing capacity |
| Yield Strength | 900 MPa (130,500 psi) min | Excellent resistance to permanent deformation |
| Elongation | 9% min | Sufficient ductility for high-strength applications |
| Hardness | HRC 32-39 | Higher hardness for increased strength |
| Primary Applications | Heavy machinery, high-pressure piping, structural connections, automotive suspensions, critical equipment assembly | |
Grade 12.9 – Alloy Steel, Quenched & Tempered
Grade 12.9 represents the highest strength grade commonly available for metric bolts. These bolts are used in the most demanding applications where maximum strength and minimum size/weight are critical.
| Property | Specification | Application Benefit |
|---|---|---|
| Material | Alloy Steel with Special Treatment | Maximum strength with controlled ductility |
| Tensile Strength | 1200 MPa (174,000 psi) min | Maximum load-bearing capacity |
| Yield Strength | 1080 MPa (156,600 psi) min | Exceptional resistance to permanent deformation |
| Elongation | 8% min | Controlled ductility for ultra-high strength |
| Hardness | HRC 39-44 | Maximum hardness for highest strength |
| Primary Applications | Aerospace, high-performance automotive, precision machinery, critical structural connections, high-stress applications | |
Standards Compliance
Our hot dip galvanized fasteners meet international standards for both mechanical properties and corrosion protection.
DIN933 – German Standard for Hex Bolts
Specifies dimensions, mechanical properties, and testing requirements for hexagon head bolts. Our bolts comply with thread lengths per ISO 4014/4017 and material requirements.
ASTM490 – American Standard for High-Strength Bolts
Specifies heat-treated alloy steel structural bolts with tensile strength of 150,000 psi min. Our Grade 10.9 and 12.9 bolts exceed these requirements.
ISO 1461 – Hot Dip Galvanized Coatings
Specifies requirements for hot dip galvanized coatings on iron and steel articles. Our coating thickness complies with ISO 1461 requirements for various bolt sizes.
ASTM A153 – Zinc Coating (Hot-Dip) on Iron & Steel
Specifies zinc coating requirements for hardware products. Our fasteners meet or exceed coating weight and thickness requirements.
Advantages of Hot Dip Galvanizing
Superior Corrosion Protection
Hot dip galvanizing provides 3-4 times thicker coating than electroplating, with typical coating thickness of 55-85μm offering 20-50 years of maintenance-free service.
Complete Coverage
The immersion process ensures complete coverage of all surfaces, including threads and recessed areas, providing 360° protection.
Excellent Abrasion Resistance
The zinc-iron alloy layers are harder than the base steel, providing excellent resistance to mechanical damage during handling and installation.
Long-Term Cost Savings
Although initial cost is higher than painting or electroplating, the extended service life and reduced maintenance provide superior lifetime cost efficiency.
Technical Specifications
Complete technical data for hot dip galvanized hex bolt nut washer sets.
Dimensions & Sizes
- Bolt Diameters: M8 to M36 (5/16″ to 1-1/2″)
- Thread Types: Metric coarse, UNC
- Length Range: 20mm to 300mm (3/4″ to 12″)
- Nut Standards: DIN934, ASTM A563
- Washer Standards: DIN125, ASTM F436
Coating Specifications
- Coating Type: Hot dip galvanized (HDG)
- Coating Thickness: 55-85 μm (ISO 1461)
- Coating Weight: 380-850 g/m²
- Salt Spray Resistance: 2000+ hours (ASTM B117)
- Appearance: Dull gray spangled finish
Material & Processing
- Base Material: Carbon/Alloy steel per grade
- Heat Treatment: Quenched & tempered
- Hydrogen Embrittlement: Baking after galvanizing
- Thread Tolerance: 6g for bolts, 6H for nuts
- Traceability: Full material certification
Grade Selection for Hot Dip Galvanized Fasteners
| Strength Grade | Tensile Strength | After Galvanizing Strength | Hydrogen Embrittlement Risk | Recommended Applications |
|---|---|---|---|---|
| Grade 8.8 | 800 MPa | Full strength retained | Low risk | General outdoor construction, fencing, utilities |
| Grade 10.9 | 1000 MPa | Full strength with proper baking | Moderate risk | Bridges, towers, heavy structural |
| Grade 12.9 | 1200 MPa | Requires special treatment | High risk | Critical infrastructure, specialized applications |
Industrial Applications
Hot dip galvanized hex bolt nut washer sets are essential for applications exposed to corrosive environments.
Infrastructure & Construction
Bridges, highway guardrails, transmission towers, and outdoor structures exposed to weather and de-icing salts.
Marine & Offshore
Docks, piers, offshore platforms, boat trailers, and coastal structures exposed to saltwater corrosion.
Utilities & Telecommunications
Power transmission structures, utility poles, cell towers, and outdoor electrical equipment.
Industrial Processing
Chemical plants, wastewater treatment facilities, agricultural equipment, and food processing plants with corrosive atmospheres.
Hot Dip Galvanized Fasteners
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