Explore our high-performance industrial fasteners manufactured under strict OEM/ODM parameters with state-of-the-art Taiwanese and German machinery.
Sinsun Hardware, established in 2006, is a leading manufacturer and global supplier of high-quality fasteners. As Northern China's largest producer of Self-Tapping Screws, we operate from a gigantic 30,000 sqm integrated facility that includes modern production zones, a 12,000 sqm smart warehouse (18,000+ pallet capacity), and multi-language customer support centers. Our yearly supply of over 8,500 containers consistently services key global markets such as the Middle East, Southeast Asia, South America, and Russia.
We offer over 20,000 SKUs of nails, screws, wires, and rivets, ensuring that your customized packaging and technical parameter specifications are fulfilled seamlessly under one roof.
Equipped with advanced German cold heading systems and precise Taiwanese technology, our vertical integration spans from raw steel coil processing to automated heat treatment.
Our engineering division manages specialized requirements, matching exact coating thicknesses, structural dimensions, performance specs, and custom OEM packaging designs.
In modern industrial machinery and automotive assembly, the integrity of a bolted joint depends heavily on stress distribution. Flat flange nuts (also known as non-serrated flange nuts) play a critical role by integrating a built-in washer surface. This structure allows the clamp load to be spread across a wider surface area without the need for a separate washer, minimizing assembly time, component count, and spatial constraints.
While serrated flange nuts are designed to "bite" into the mating material to prevent back-off under high vibration, they can strip away protective coatings, leading to localized galvanic corrosion. In contrast, flat flange nuts feature a smooth, non-serrated contact face. This smooth surface provides a consistent coefficient of friction, ensuring precise torque-tension relationships during assembly, while preserving paint, plating, or anodized layers on structural elements like PV racking, automotive chassis, or electrical enclosures.
Sinsun Hardware manufactures OEM flat flange nuts in strict compliance with international specifications, ensuring total interchangeability. Standard parameters include DIN 6923, ISO 4161, and ASME B18.2.4.2M. Below is an overview of our typical product parameters:
| Characteristic / Metric | Metric Standards (DIN/ISO) | Imperial Standards (ANSI/ASME) | Sinsun Quality Guarantee |
|---|---|---|---|
| Thread Sizes Offered | M3 to M36 | #4 to 1-1/2" | 100% Go/No-Go Gauge Tested |
| Material Grades | Class 8, 10, 12 Carbon Steel / Stainless Steel A2 & A4 | Grade 5, Grade 8, Stainless Steel 304/316 | Traceable Mill Certificates (Xingtai Steel) |
| Dimensional Accuracy | +/- 0.02 mm (Precision Class A) | +/- 0.001 inches | Optical Sorter Checked |
| Surface Roughness (Flange) | Ra ≤ 0.4 μm | Ra ≤ 16 μin | Eliminates micro-galling |
| Corrosion Resistance | Up to 1,500 Hours (Zinc-Nickel / Geomet) | Up to 1,500 Hours (Mechanical Galvanized) | Salt Spray Tested (ASTM B117) |
Explore our history of growth and technological expansion, evolving from a dedicated manufacturer in Northern China to an international supply chain partner exporting tens of thousands of tons of high-grade fasteners annually.
Sinsun began with a singular focus: to build a factory dedicated to self-tapping screws. This specialization established our core expertise, ensuring a foundation of precision metallurgy from the ground up.
The year 2012 marked a pivotal step for Sinsun with the establishment of our dedicated Export Department. Our specialized fasteners began reaching international projects and global OEM supply pipelines.
Sinsun expanded control over raw materials by adding four spheroidizing furnaces and in-house wire drawing capabilities. This control over raw metal structures ensured superior quality in our final products.
Our production capability was enhanced with German multi-station cold heading machines and advanced Taiwanese tech. We expanded our product range to include complex drill-tail screws and specialty nuts.
Achieved 36,000 tons in annual production, fulfilling international orders with over 1,100 export containers. Sinsun became a trusted partner for large-scale industrial buyers.
Operated a 12,000 sqm smart warehouse, featuring a 1,200 sqm ready-stock zone. This system supports efficient logistics, fast loading times, and stable supply chains.
The addition of four advanced heat treatment lines boosted our internal capacity, guaranteeing consistent structural hardness (HRC 28-32) and ensuring on-time delivery.
At Sinsun Hardware, quality is engineered, not checked. We control every stage of production within our 30,000 sqm integrated facility to ensure our fasteners meet strict industrial performance standards.
Our manufacturing starts with raw materials sourced directly from Xingtai Steel. We use selected carbon steels (10B21, 1022a, 35K, 45#) and stainless steels (SS304, SS316) to ensure consistent mechanical performance in every batch.
By operating our own gas-fired spheroidizing furnaces, we soften the steel microstructure and eliminate internal stresses before cold heading, preventing micro-fractures in the finished fastener.
Utilizing high-precision multi-station cold heading machines imported from Germany and Taiwan, we form fastener heads, flanges, and threads with tight dimensional tolerances (+/-0.02mm).
Our four newly added heat treatment lines in 2025 allow us to fine-tune the hardness (HRC 28-32 for standard structural parts, and higher for self-drilling parts) and tensile strength (>1000 MPa) of our products.
We offer customized plating treatments (Hot-Dip Galvanizing, Mechanical Zinc, Zinc-Nickel, and Geomet) that can withstand over 1,000 hours of salt spray testing, providing long-term corrosion protection.
Every batch of OEM flat flange nuts and screws passes through optical sorting machines to verify tolerances, thread pitches, and surface finish before entering our customized packing lines.
As a supplier to over 50 countries, Sinsun Hardware understands that technical compliance, customs clearance, and secure packaging are critical to your supply chain reliability.
We offer tailored packaging options based on your requirements, including 3D design previews, heavy-duty carton labeling, color box branding, and moisture-resistant pallet wrapping.
Every shipment is backed by comprehensive quality certifications, including EN 10204 3.1 material certificates, ISO 9001 compliance logs, and raw material chemical analysis reports.
Our 12,000 sqm smart warehouse holds up to 18,000 pallets, enabling us to consolidate shipments and maintain reliable lead times, even during high-demand seasons.
We are committed to modernizing fastener manufacturing through continuous investment in smart factory technologies, material science, and sustainable production processes.
We are integrating automated robotic packaging lines and upgrading our optical sorters to achieve close-to-zero defect rates in large-volume production runs.
We are expanding our range of trivalent chromium plating and water-based anti-corrosion coatings to help our partners meet strict environmental standards (RoHS/REACH).
Implementing RFID inventory tracking throughout our 12,000 sqm facility will provide real-time updates and faster fulfillment times for long-term contract customers.
Get authoritative answers to common engineering, procurement, and manufacturing questions about flat flange nuts.
Discover our broader range of industrial fasteners, manufactured to the same rigorous standards as our flat flange nuts.
Contact Sinsun Hardware's engineering team to discuss material standards, dimensional requirements, or customized packaging options.
