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Hex cap screws are precision-engineered fasteners with a six-sided head and a smooth, chamfered bearing surface, designed for high-strength bolted connections in machinery, equipment, and structural assemblies. They are manufactured to tighter tolerances than standard hex bolts, with rolled threads for improved fatigue resistance and consistent torque-tension performance.
Zhejiang Chance & Union supplies hex cap screws in carbon steel, alloy steel, and stainless steel, covering property classes 8.8, 10.9, and 12.9 (metric) as well as ASTM A325 and A490 grades. Our production processes include cold heading, thread rolling, heat treatment, and precision coating, ensuring each screw meets or exceeds application requirements.
30,000 m²
Facility Area
80+
Cold Headers
800 t
Monthly Capacity
2,000 t
Warehouse Stock
Product Specifications
Diameter rangeM6 – M48 · 1/4″ – 2″
Length range10 mm – 300 mm · custom lengths
Thread class6g (metric) · 2A (UNC) · rolled
Property classes8.8 · 10.9 · 12.9 · ASTM A325 · A490
MaterialsCarbon steel · alloy steel · stainless 304/316
Finish optionsZinc plated · HDG · phosphate · Dacromet · Xylan
Manufacturing Performance
Production Efficiency
Quality Metrics
Core Advantages for B2B Procurement
Supply Chain Reliability
- Permanent stock of 5,000+ specifications ready for immediate dispatch
- Storage capacity exceeding 2,000 tons ensures buffer against demand spikes
- 24-hour order processing with 3-day shipping for standard items
- Custom order lead time: 7–25 days, supporting just-in-time procurement
- Multi-station cold headers (80+ units) provide production redundancy
Quality & Compliance
- ISO 9001 and IATF 16949 certified quality management systems
- 100% optical sorting for dimensional accuracy
- Material test reports (MTR) with heat numbers for full traceability
- 72-hour salt spray testing per ASTM B117 for coating validation
- Tensile and hardness testing per ASTM E8 and E18 standards
R&D & Custom Engineering
With nearly 20 years of industry experience, our R&D team has developed over 1,000 custom fastener solutions for clients across 25 countries. We invest 5% of annual revenue into R&D, focusing on:
- Joint design optimization: Clamp load calculation, torque-tension correlation, and friction coefficient analysis for critical assemblies
- Custom geometry: Non-standard head dimensions, under-head fillet radii, and special thread configurations
- Material selection: Guidance on carbon steel, alloy steel, or stainless steel based on strength and environmental requirements
- Prototyping: Rapid sample production for fit and performance validation before mass production
Application Scenarios
- Heavy machinery: Engine blocks, transmission housings, and structural frame connections
- Automotive: Chassis components, suspension systems, and drivetrain assemblies
- Industrial equipment: Pump and compressor mounting, gearbox covers, and motor bases
- Aerospace & defense: High-strength structural joints and critical fastening points
- Renewable energy: Wind turbine components, solar tracker assemblies, and hydroelectric equipment
Procurement Considerations
When sourcing hex cap screws for industrial applications, consider the following factors that directly impact total cost of ownership and assembly reliability:
- Grade selection: Property class 8.8 for general-purpose applications; 10.9 for higher strength; 12.9 for maximum load capacity. ASTM A325 and A490 for structural bolting.
- Coating compatibility: Zinc plating for moderate corrosion protection; hot-dip galvanizing for outdoor exposure; Dacromet for high-salt environments; Xylan for lubricity and corrosion resistance.
- Thread fit: Class 6g/2A for standard clearance; tighter fits available for precision assemblies.
- Length tolerance: Standard lengths per DIN/ISO; custom lengths for specific joint designs.
- Lot traceability: Full documentation from raw material to finished product, essential for regulated industries.
Frequently Asked Questions
What is the difference between a hex cap screw and a standard hex bolt?
Hex cap screws are manufactured to tighter tolerances than standard hex bolts, with a chamfered bearing surface and a controlled head height. They are typically used in applications requiring precise torque control and consistent clamp load. Standard hex bolts have a larger head and are generally used in structural applications where tolerances are less critical.
What property classes are available and what do they mean?
Metric hex cap screws are available in property classes 8.8, 10.9, and 12.9. The first digit indicates tensile strength (e.g., 8 = 800 MPa minimum), and the second digit indicates yield strength ratio (e.g., .8 = 80% of tensile). We also supply ASTM A325 (120 ksi) and A490 (150 ksi) grades for structural applications.
How do you ensure consistent torque-tension performance?
We use rolled threads for improved fatigue resistance and controlled friction characteristics. Each batch undergoes torque-tension testing to verify consistent performance. Our IATF 16949 certified processes ensure strict control over thread geometry, surface finish, and lubrication.
What is your typical lead time for hex cap screws?
Standard sizes in stock can ship within 3 days. For custom dimensions, materials, or coatings, lead time is typically 7 to 25 days depending on order quantity and specification complexity. We support both small-batch prototyping and large-volume production orders.
Can you produce hex cap screws to non-standard specifications?
Yes. Our R&D team has developed over 1,000 custom fastener solutions. We can accommodate non-standard head dimensions, thread configurations, custom materials, and special coating requirements based on your project needs. We provide engineering consultation to optimize fastener design for your application.
