High Strength Bolts Grade 10.9

High Strength Bolts Grade 10.9 — Quenched & Tempered Alloy Steel Hex Bolts | M12–M36

Grade 10.9 high strength bolts are quenched and tempered alloy steel fasteners delivering a minimum tensile strength of 1040 MPa and yield strength of 940 MPa. Manufactured from medium carbon alloy steel (such as 42CrMo / SCM440), these bolts are engineered for heavy-duty structural and mechanical applications where superior load-bearing capacity is essential. Our Grade 10.9 bolts meet DIN 6914, ISO 898-1, and ASTM A490 equivalent standards, with full heat treatment records and material certification.

Material & Specifications

Size Range	M12 to M36 / 1/2″ to 1-1/2″
Standard	DIN 6914, ISO 898-1, GB/T 1228, ASTM A490 (equivalent)
Material	Alloy Steel — 42CrMo (SCM440), 35CrMo (SCM435), Boron-treated steel
Surface / Coating	Hot-Dip Galvanized (HDG), Dacromet, Multi-Element Alloy Co-Permeation, Black Oxide
Tensile Strength	≥ 1040 MPa (Grade 10.9)
Yield Strength	≥ 940 MPa
Hardness	320-380 HV (HRC 32-38)

Surface Treatment & Zinc Coating Quality

At BoltNutsPlus, we understand that surface treatment is critical to fastener longevity and performance. Our products undergo rigorous coating processes to ensure maximum corrosion resistance and durability. We offer five premium coating options, each tested to international standards:

• Hot-Dip Galvanizing (HDG) — Thick zinc layer (50-120μm) providing superior long-term corrosion protection for outdoor, marine, and industrial environments. Compliant with ISO 1461 / ASTM A153 standards. Salt spray resistance: 500-1,000+ hours. Ideal for structural steel assemblies exposed to harsh weather.
• Electroplated Zinc Blue-White (Zn Blue/White) — Bright, clean silver-blue appearance with 5-15μm zinc layer. Cr3+ passivation technology, fully RoHS compliant. Ideal for indoor machinery, electronics, and general-purpose applications requiring aesthetic appeal and moderate corrosion resistance.
• Color Zinc / Yellow Zinc (Iridescent Passivation) — Multi-colored iridescent passivation film offering enhanced corrosion resistance (100-200 hours salt spray) with a distinctive golden finish. Widely preferred in automotive, agricultural equipment, and construction machinery sectors for its balanced protection and visual appeal.
• Dacromet Coating — Advanced water-based zinc-chromium coating technology with NO hydrogen embrittlement risk. Provides 1,000+ hours salt spray resistance, making it the preferred choice for high-strength fasteners in extreme environments. Environmentally friendly (no heavy metal discharge), RoHS/ELV compliant, ideal for automotive and wind energy applications.
• Multi-Element Alloy Co-Permeation — Zinc-aluminum-rare earth alloy layer offering 2-3x the corrosion resistance of traditional galvanizing. Features self-healing properties at scratch points, ensuring long-term protection even in damaged areas. Ideal for critical infrastructure, power transmission towers, coastal projects, and marine installations.

Key Features

• Quenched and tempered alloy steel delivers 1040 MPa minimum tensile strength
• Superior fatigue resistance for cyclic loading applications
• Precision thread-rolling after heat treatment ensures dimensional accuracy
• Full heat treatment records and Jominy hardenability curves available
• Hydrogen embrittlement relief baking after electroplating (mandatory for 10.9+)
• EN 10204 3.1 material certificate included with every batch

Applications

• Structural steel connections in high-rise buildings and bridges
• Heavy machinery, cranes, and lifting equipment
• Power transmission towers and substation structures
• Wind energy turbine base and tower connections
• Railway and metro infrastructure fastening
• Mining equipment and offshore platform structures

Why Choose BoltNutsPlus?

• ISO 9001:2015 Certified Manufacturing — consistent quality you can trust on every batch
• 15+ Years of Export Experience — serving 40+ countries across 6 continents
• Full Traceability — material certificates (EN 10204 3.1) and comprehensive test reports included
• Custom Packaging & OEM/ODM — your brand identity, your specifications, our precision manufacturing
• Third-Party SGS / Bureau Veritas Inspection Available upon request
• 24-Hour Quote Response — same-day reply for urgent requirements; standard 24-hour turnaround