35CrMo Alloy Steel Grade 10.9 Black Oxide Hex Bolts
Product Overview
Grade 10.9 black oxide hex bolts are high-strength fasteners manufactured from 35CrMo alloy steel and coated with black oxide for enhanced surface protection. These bolts feature partial threads and are designed to deliver exceptional tensile strength, wear resistance, and reliability in mechanical and structural assemblies. Commonly used in automotive, construction, and heavy machinery applications, these bolts meet the high-performance demands of industrial environments.
Product Specification Table
| Specification | Detail |
|---|---|
| Product Name | Grade 10.9 Black Oxide Hex Bolt |
| Material | 35CrMo Alloy Steel |
| Strength Grade | Grade 10.9 |
| Thread Type | Metric / UNC (Partial Thread) |
| Surface Finish | Black Oxide |
| Standards | ISO 4014 / DIN 933 / ANSI B18.2.1 |
| Size Range | M6–M30, 1/4″–1-1/4″ |
| Length Range | 12mm–200mm |
Technical Parameters
| Mechanical Property | Value |
|---|---|
| Tensile Strength | ≥1040 MPa |
| Yield Strength | ≥940 MPa |
| Hardness | 32–39 HRC |
| Proof Load | 90% of minimum tensile strength |
| Thread Engagement | Partial Thread |
| Operating Temperature | -50°C to 350°C |
Material Introduction & Manufacturing Process
35CrMo is a high-grade alloy steel known for its high fatigue resistance, tensile strength, and hardenability. It is particularly suited for bolts that are expected to perform in high-stress, vibration-prone environments.
Manufacturing Process Steps:
Raw material quality inspection
Cold or hot forging based on bolt size
CNC or rolling for precise thread formation
Heat treatment (quenching + tempering)
Black oxide surface treatment
Dimensional and mechanical testing
Final packaging and labeling
This sequence ensures consistent thread fit, dimensional precision, and optimal performance in critical connections.
Typical Applications & Industries
Grade 10.9 black oxide hex bolts with partial threads are ideal for load-bearing assemblies requiring controlled grip length and thread engagement. Applications include:
Engine and chassis components in the automotive sector
Steel frame connections in building construction
Press machinery and hydraulic systems
Agricultural machinery and trailers
Industrial cranes and lifting equipment
Product Benefits & Competitive Features
High Strength Black Oxide Hex Bolts with Partial Thread
Flybear Fastener ensures superior product quality and competitive pricing for Grade 10.9 hex bolts.
Material Excellence: 35CrMo offers better tensile and fatigue strength than standard carbon steels
Precision Thread Control: Partial threading allows accurate positioning and optimal shear load transfer
Advanced Surface Protection: Black oxide adds moderate corrosion resistance and improved lubricity
Customization Flexibility: Available in various thread pitches and head styles as per client drawings
Strong Inventory & Timely Delivery: Large in-stock quantities reduce lead time
Professional Support: Our engineers assist with technical selection and application challenges
Company Quality Assurance & Testing
Each production batch from Flybear undergoes strict inspection and documentation to meet international quality standards:
Material certificates (EN 10204 3.1)
Hardness and tensile testing reports
Dimensional checks using thread gauges and calipers
Surface treatment adherence (black oxide thickness and finish)
Selection & Procurement Guide
When selecting Grade 10.9 black oxide hex bolts, buyers should consider:
Required load-bearing performance and shear force requirements
Whether a partial thread is needed for the grip length
Environmental factors affecting surface coating needs
Thread pitch, bolt length, and standard compatibility
For OEM, machinery, or infrastructure projects, please prepare drawings or specifications. Our team can support product matching or suggest equivalent replacements.
Conclusion & Company Promotion
We always uphold the philosophy of “quality first, customer foremost,” and are committed to providing customers with high-quality fastener products and one-stop fastening solutions.
Explore our full bolt collection or contact us to discuss project specifications and request a quote tailored to your industry needs.
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