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Stainless Steel Bolts and Washers
Product Overview
Bolts and washers are cold-formed from austenitic stainless steels 304 (A2) and 316 (A4). Bolts conform to ISO 3506 property classes 70 and 80 with tensile strength from 500 MPa to 800 MPa. Washers are produced per DIN 125 and ISO 7089, available in flat, spring, and beveled configurations. Passivation per ASTM A967 removes free iron and restores the passive layer. Dimensional tolerances follow ISO 965-2 and DIN 125, with full material traceability.
Key Features
- Corrosion resistance from chromium oxide passive film.
- Consistent thread accuracy for reliable engagement.
- Available in multiple head styles and drive types.
- Washers provide load distribution and anti-loosening.
- Suitable for high-strength structural applications.
| Attribute | Specification |
| Material grades | 304 (A2), 316 (A4), 410 (martensitic, optional) |
| Diameter range (metric) | M4 – M30 (coarse and fine pitch) |
| Diameter range (inch) | #8 – 1-1/4 inch (UNC/UNF) |
| Property classes | 70 (500–700 MPa), 80 (700–800 MPa), 100 (900–1000 MPa) |
| Washer types | Flat (DIN 125), spring (DIN 127), beveled (DIN 6319) |
| Surface treatments | Passivation, zinc plating, wax coating, PTFE |
| Head styles (bolts) | Hex, hex flange, socket, countersunk |
| Drive types | Hex, Torx, Phillips, slotted |
Construction
- Steel structure connections
- Bridge and infrastructure
- Building facade systems
Industrial
- Heavy machinery assembly
- Pump and valve flanges
- Equipment mounting
Energy
- Solar panel mounting
- Wind turbine components
- Power transmission
Use the formula T = K × d × F to determine tightening torque (K = nut factor, d = nominal diameter, F = preload). Lubricated threads (K ≈ 0.15–0.18) require lower torque than dry threads (K ≈ 0.25–0.30). Always verify with a calibrated torque wrench and perform relaxation checks after initial tightening. Use hardened washers under the bolt head and nut to distribute load and prevent bearing damage.
Frequently Asked Questions
Production & Customization
Chance & Union leverages the manufacturing capabilities of Shengzhao Metal to offer custom bolts and washers in non-standard diameters, lengths, and head styles. Custom thread forms, drive recesses, and surface finishes are available upon request. We support low-volume prototyping and high-volume production runs, with strict adherence to ISO 9001 quality management and full material traceability per EN 10204 3.1. Our engineering team can assist with design modifications for specific applications.
Storage & Handling
- Store in a clean, dry area with relative humidity below 55% to maintain passivation.
- Avoid contact with carbon steel, copper, or graphite to prevent galvanic corrosion or contamination.
- Use plastic or coated trays and bins; separate by grade, size, and type.
- Implement FIFO rotation; recommended shelf life up to 36 months in original packaging.
- Inspect for rust spots or discoloration before use; re-passivate if necessary.
Leveraging the factory's robust R&D and production capabilities, we specialize in high-strength rivets bolts, nuts, washers, pins, screws, and various non-standard custom parts. As experienced Custom Stainless Steel Bolts and Washers Suppliers, we provide flexible manufacturing solutions for different customer requirements. Our product range covers materials including stainless steel, alloy steel, aluminum alloy, copper, and special alloys, utilizing processes such as cold heading, hot forging, and CNC machining. Our products are exported to over 25 countries, serving more than 200 clients.
Chance & Union is committed to seamlessly connecting "Manufactured in China" with the international market, providing global customers with one-stop fastening solutions from R&D to mass production through professional technology and exceptional quality.
