Direct supply from Northern China's largest advanced manufacturing base.
In structural design, stress distribution is key. Fender washers are distinct because of their significantly larger Outer Diameter (OD) relative to their Inner Diameter (ID).
By increasing the bearing surface area under the head of a threaded fastener, fender washers disperse clamping forces across thin sheet metal, plastics, and wood. This prevents pulling through the parent material and avoids localized mechanical buckling.
Sinsun customizes standard systems including DIN 9021, ISO 7093, and USS/SAE flat washer standards. Our cold-rolled processes achieve thickness tolerances within ±0.02mm, maintaining consistent clamping force on high-vibration assembly lines.
We source carbon steels, stainless steel (SS304/SS316), and structural alloy steels exclusively from top mills. These undergo cold-stamping and heat treatment to guarantee hardness up to HRC 28-32 and tensile properties capable of holding under high torque loads.
| Material Grade | Applicable Specifications | Size Range (ID/OD) | Surface Plating & Corrosion Resistance | Typical Applications |
|---|---|---|---|---|
| Carbon Steel C1008/C1022A | DIN 9021, ISO 7093, ANSI B18.21.1 | M3 - M24 (Inner Diameter) | Clear Zinc, Yellow Zinc, Hot Dip Galvanized (1,000+ Hr Salt Spray) | Automotive Body Panels, Structural Timber Joints, HVAC Assembly |
| Stainless Steel 304 / 316 | ASTM A240, EN 10088-2 | #6 - 1" Nominal sizes | Passivated, Electropolished | Offshore Platforms, Marine Equipment, Chemical Processing |
| Structural Spring Steel | DIN 137, Custom High-Tensile | Custom Engineering Drawings | Zinc Flake (Geomet / Dacromet), Zinc Nickel Plating | Heavy Machinery Chassis, Wind Turbine Bracket Mounts |
Operating a 30,000 m² integrated production base in Northern China to guarantee cost efficiency and reliable delivery.
We maintain long-term partnerships with Xingtai Steel and Ansteel Group. All incoming wire rods undergo in-house spheroidizing annealing and drawing to ensure consistent steel grain structure, which helps prevent internal micro-cracks during stamping.
Our workshop is equipped with German cold-heading machines and Taiwanese stamping systems, operating alongside four heat treatment lines. Process checks monitor flatness, thickness, and hardness at every step.
Explore Sinsun's expansion from 2006 to 2025, driven by technological investment and global supply capabilities.
Established our first manufacturing workshop in Northern China, focusing on high-volume standard self-tapping screws and basic hardware parts.
Launched specialized export channels and established partnerships with key distributors in South America, Russia, and the Middle East.
Upgraded the production lines with multi-station cold-heading equipment and automated stamping arrays to improve precision.
Expanded to an annual capacity of 36,000 tons. Opened a 12,000 m² smart storage facility with an automated ERP picking system.
Sinsun fender washers are engineered to meet the requirements of modern structural design and harsh environmental conditions.
Large-diameter fender washers protect aluminum rails from localized stress cracking caused by high winds. Our hot-dip galvanized coating provides long-term corrosion resistance for outdoor installations.
Thin-gauge steel and composite body parts require wider load-bearing solutions to prevent cracking at joint connections. Our washers maintain precise flatness tolerances (< 0.1mm deviation) to ensure secure fits on automated lines.
Whether securing wood-to-metal framing or anchoring HVAC ductwork, our standard USS and SAE fender washers help prevent fastener pull-through under dynamic building loads.
Ensuring compliance with global engineering codes and regulatory standards.
Our quality management system tracks the entire manufacturing process, from raw wire identification to finished cargo shipment.
Traceability GuaranteedUsing advanced zinc coatings and Dacromet passivations, our washers are tested to withstand environmental degradation in coastal areas.
ASTM B117 CompliantWe provide detailed Material Test Reports for every shipment, certifying chemical composition, hardness values, and tensile test performance.
Full Traceability ReportsHelping procurement directors, industrial distributors, and OEMs optimize cost and delivery schedules.
We provide tailormade box designs, pallet packaging, and direct labeling to integrate with your existing assembly lines or retail shelves.
Our proximity to Tianjin Port allows us to manage shipping logistics efficiently. We offer flexible options including FOB, CIF, DDP, and LCL consolidation.
See how Sinsun engineering resolves complex fastening challenges across diverse global environments.
Challenge: A tier-1 automotive supplier needed customized flange connections with high vibration resistance and weight optimization.
Sinsun Solution: We designed a component using high-tensile steel and specialized thread-locking coatings, supported by torque and tension testing.
Result: 15% weight reduction and zero failures during 2,000-hour dynamic vibration tests.
Challenge: An engineering firm required large-diameter bolts and wide washers for saltwater splash zones on offshore installations.
Sinsun Solution: Provided high-grade duplex stainless steel (SS316) parts treated with our specialized chemical passivation process.
Result: Zero rust or material degradation reported after 3 years of marine exposure.
Sinsun continues to research new materials, coatings, and production methods to support high-performance industrial applications.
By refining annealing temperatures and micro-alloying techniques, we are developing thinner fender washers that maintain high strength to support automotive weight-reduction goals.
We are phasing out Cr6+ (hexavalent chromium) in favor of trivalent zinc and organic coatings that meet RoHS and REACH environmental regulations.
Our packaging facilities are testing high-resolution cameras that check dimensional parameters on every washer to ensure consistent product sizing.
Common questions from design engineers and procurement teams regarding fender washer selection and production.
Fender washers have a larger outer diameter (OD) relative to their inner diameter (ID) compared to standard flat washers. While standard flat washers are designed to distribute local tension, a fender washer spreads loads across a larger surface area, making it suitable for thin sheet metals, soft wood, and plastics.
We offer hot-dip galvanizing (HDG), electro-galvanized zinc (clear, yellow, and black), trivalent passivations, and specialized zinc flake coatings (such as Geomet or Dacromet). These coatings help protect components from rusting in outdoor and corrosive industrial environments.
Yes. Custom ODM/OEM manufacturing is a core part of our business. Our technical team works with your engineering designs to produce custom dimensions, thickness ranges, and specialty materials to suit your requirements.
Lead time depends on order size and custom plating requirements. Standard configurations are usually shipped in 4 to 6 weeks. Our ERP system helps optimize scheduling to ensure on-time delivery.
Every batch of raw wire rod is tracked from source to delivery. We conduct regular mechanical, dimensional, and metallurgical checks in our laboratory, providing complete Material Test Reports (MTR) with every shipment.
We manufacture a wide range of standard sizes including metric dimensions under DIN 9021 and ISO 7093-1/2, as well as imperial dimensions matching USS and SAE standards.
Explore our wider range of certified structural hardware and anchors.
Speak directly with our technical team today. We provide engineering drawings, mechanical calculations, and custom prototype samples within 48 hours.
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