Explore our highly-engineered product lines delivering maximum structural performance across global distribution channels.
Engineered for permanent thread integration in thin-sheet metal assemblies, providing high resistance to torque-out and push-out forces.
Projection welding is a localized resistance welding method that concentrates current and thermal pressure at specific designated points on the weld nut—known as the weld projections. For Square Weld Nuts (DIN 928), four uniform corner projections are precision-formed during cold heading. During assembly, high electrical current flows exclusively through these projections, heating them to forging temperature rapidly before applying pneumatic pressure to fuse the nut permanently to the parent metal plate.
By using a square body geometry, these nuts distribute rotational torque loads across a significantly larger surface area than conventional hex nuts. This makes them ideal for structural locations with restricted spatial access, where traditional wrench tightening is impossible and blind-threading reliability is critical.
Achieving a reliable weld interface requires strict control over raw material composition. Sinsun Hardware utilizes low-carbon steel alloys (such as premium C1008/C1010 or optimized C1022A grades) that exhibit superior weldability. High carbon content raises the risk of martensite formation in the Heat-Affected Zone (HAZ), which can lead to brittle failures. Our precise metallurgical composition ensures that under standard projection welding programs, the fusion zone remains ductile, tough, and fully capable of matching the parent metal's tensile limits.
Sinsun Hardware is a leading manufacturer and global supplier of high-quality fasteners. Operating as Northern China's largest producer of Self-Tapping Screws, we work from an expansive 30,000 sqm integrated facility. This mega-complex houses modern production zones, a 12,000 sqm smart warehouse holding an 18,000+ pallet capacity, and multi-language customer support centers.
Our annual logistics reach exceeds 8,500 shipping containers, supporting heavy industries, automotive supply lines, and major distributors across the Middle East, Southeast Asia, South America, and Russia. We control the complete process from raw wire drawing to final heat treatment, offering our clients a stable supply chain and unmatched quality control.
Discover our expansion path, driven by process optimization, precision engineering, and technological investments.
Sinsun Hardware founded in Northern China with a core focus on domestic industrial hardware supply.
Established dedicated export divisions, securing entry into key European, Russian, and Middle Eastern markets.
Integrated German-engineered multi-station cold heading systems to achieve tight tolerance levels (±0.02mm).
Achieved a 36,000-ton annual output with four automated in-house heat treatment lines operational.
Combining German multi-station forming machinery and Taiwanese tooling technology to guarantee precision parts.
Our quality control starts at the source. We source premium raw material wire rods from Ansteel Group and Xingtai Steel. We perform in-house spheroidizing annealing and wire drawing to control carbon distribution and surface finish before heading.
Using German-imported multi-station cold heading systems alongside Taiwanese tooling, we achieve production rates up to 1,200 pieces/min. This ensures dimensional tolerances are held within ±0.02mm, guaranteeing correct positioning on weld pins.
We run four inline heat-treating furnaces processing up to 20 tons daily. This allows us to achieve core tensile strengths exceeding 1,000 MPa and maintain a surface hardness range of HRC 28-32, preventing deformation during high-pressure welding cycles.
How Sinsun OEM square weld nuts meet the requirements of modern global manufacturing sectors.
Engineered to withstand continuous vibration and cyclic stress. Our DIN 928 square weld nuts are integrated into automotive frame rails, seat tracks, engine cradles, and suspension mounts. They provide reliable resistance to thread stripping under dynamic impact loads.
Heavy excavators, agricultural implements, and mining machinery operate under intense vibrational load. We manufacture heavy-duty weld nuts designed to maintain joint integrity, preventing structural failures on the job site.
Outdoor utility tracking structures require corrosion resistance. Our specialized coatings, such as Dacromet and hot-dip zinc diffusion, protect the fasteners from environmental exposure, providing over 1,000 hours of salt spray resistance.
For clean-room and high-voltage power cabinets, our square weld nuts provide clean joints with minimal spatter. This eliminates clean-up steps and protects internal electronic components from metallic particles.
Developing fastening technologies for the next generation of industrial applications.
Modern manufacturing is shifting towards lightweight materials and automated assembly lines. At Sinsun Hardware, our research and development programs focus on three major trends:
One of the primary challenges in high-speed welding lines is weld spatter adhering to the internal threads of the nut. This requires expensive tapping rework. Sinsun is developing advanced dry-film and fluoropolymer barrier coatings that repel molten slag. This ensures threads remain clear and run-in torque matches design parameters without manual cleaning.
As the automotive industry increases the use of high-strength steels (AHSS) and aluminum alloys, welding parameters are becoming more narrow. Sinsun is testing new ultra-low carbon alloys containing titanium and boron micro-additions. This ensures strong weld fusion with minimal heat output, preserving the structural integrity of thin sheets.
To support Industry 4.0 automation, Sinsun is integrating micro-geometrical features into the pilot flange of our square weld nuts. Optical sensors on robotic welding heads can detect these details to verify correct orientation, placement, and alloy type before triggering the weld cycle.
Combining automated material logistics, real-time quality control, and export infrastructure to support global supply chains.
Our 12,000 sqm smart warehouse uses an ERP-controlled storage and retrieval system. With a capacity of over 18,000 pallets, we maintain structural stocks of standard parts. This system ensures quick response times, allowing containerized orders to be loaded and shipped efficiently.
To meet high quality standards, our optical sorting systems inspect finished parts at speeds up to 3,000 units per minute. Cameras verify dimensional tolerances, thread accuracy, and projection height, helping us achieve our goal of zero defects.
Based in Northern China, our plant has direct access to high-volume steel production centers and deepwater shipping terminals. This proximity reduces transport times and logistics costs. Over 8,500 shipping containers leave our docks annually, giving us the experience to navigate complex customs procedures smoothly.
Every shipment is fully traceable and meets international quality standards.
We monitor our production using Statistical Process Control (SPC). From the hot-rolled wire rod to the packaged carton, each lot receives a unique identifier. This allows us to trace chemical analysis, wire drawing parameters, cold-heading dimensions, and heat treatment logs.
We manufacture square weld nuts to match global specifications, including DIN 928, ASME B18.2.2, JIS B1196, and ISO equivalents. Our engineering team can also customize dimensions to fit proprietary corporate standards.
Our ISO 9001 quality lab verifies fastener performance. We conduct tensile testing, hardness checks (HRC/HV), microstructural analysis, torque-tension testing, and salt spray exposure tests to confirm corrosion protection.
From custom design to delivery, we ensure transparency and quality at every step.
We analyze your application requirements, looking at weld equipment specs, plating needs, and target load demands.
Our engineers provide detailed CAD drawings and cost estimates within 48 hours for review.
We produce tooling and supply physical samples for welding and torque testing in your facility.
Upon sample approval, we begin production. Our automated lines manufacture your parts, and our logistics team handles delivery.
See how our engineering support helps OEM customers resolve fastening challenges.
Challenge: A Tier-1 automotive supplier faced thread failures on an engine mount bracket due to vibration.
Sinsun Solution: We redesigned the weld nut with a custom medium-carbon boron alloy and optimized the corner projections for deeper weld penetration.
Result: Passed all 2,000-hour vibration and pull-out tests, helping the customer achieve a 15% weight reduction.
Challenge: Heavy structural elements in a saltwater environment suffered from fast galvanic corrosion.
Sinsun Solution: Recommended high-tensile fasteners finished with a duplex zinc-flake passivation coating.
Result: Zero fastener failures reported after 18 months of exposure, exceeding the customer's lifespan expectations.
Technical information regarding ordering, materials, and custom specifications.
Complete your assembly specification with our range of nuts, bolts, anchors, and specialized screws.
Partner with Sinsun Hardware for technical expertise, automated production, and reliable logistics.
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