The Square Washer (commonly referred to as a square plate washer, timber connector washer, construction square washer, or DIN 436 / DIN 434 fastener) is a heavy-duty, flat rectangular mechanical washer engineered to provide a significantly larger bearing surface area than standard circular flat washers. By distributing clamping torque across a broader contact surface, square washers prevent bolt heads or hex nuts from crushing into wood timber, curtain wall framing, aluminum extrusions, or concrete anchor plates. Manufactured in carbon steel (Class 4 / 100HV–200HV) and austenitic stainless steel (SS304/A2 and SS316/A4), our square plate washers adhere strictly to global ISO standards.
Technical Specifications of Carbon Steel & Stainless Steel Square Washers
We supply flat square plate washers (DIN 436) as well as tapered square washers for U-channels and I-beams (DIN 434 / DIN 435). Hot-dip galvanized coatings (HDG) are specifically offered for timber construction and outdoor pole hardware to resist severe atmospheric corrosion.
| Washer Style / Standard | Raw Material Base | Hardness / Strength Grade | Primary Structural Role | Available Surface Treatments |
|---|---|---|---|---|
| DIN 436 Flat Square Washer | Low Carbon Steel (Q195 / Q235B) | 100 HV – 140 HV (Class 4) | Heavy Load Distribution on Timber & Steel Framing | Plain Black, Electro-Zinc Plated (Blue-White / Yellow), HDG |
| DIN 434 / DIN 435 Tapered Square | Medium Carbon Steel (45#) | 140 HV – 200 HV | Leveling Sloped Flanges on U-Channels & I-Beams (8% / 14% Taper) | Black Oxide, Electro-Zinc, Hot-Dip Galvanized (HDG) |
| Stainless Steel A2 (SS304) | Austenitic Stainless Steel SS304 (1.4301) | 140 HV – 200 HV | Corrosion Resistant Timber & Curtain Wall Fastening | Passivated Clean Natural / Electropolished |
| Stainless Steel A4 (SS316) | Austenitic Stainless Steel SS316 (1.4401) | 140 HV – 200 HV | Marine & Harsh Chemical Timber Connections | Passivated Clean Natural / Electropolished |
Multi-Stage Hydraulic Stamping and Surface Finishing Process
At our manufacturing facility in Handan, China, square washers are produced using heavy-duty hydraulic pressing lines, automatic deburring barrels, and galvanizing tanks:
- Heavy Hydraulic Plate Blanking: Premium steel plates or strip coils pass through high-tonnage blanking dies to shear outer square dimensions and pierce central round holes in a single stroke.
- Vibratory Edge Deburring: Blanked square plates undergo ceramic tumbling to round off sharp corners and edges, preventing operator injury and ensuring flush seating.
- Hot-Dip Galvanizing Treatment (HDG): Cleaned carbon steel plates are immersed in a 450°C molten zinc bath, forming a durable 45–85 µm zinc-iron alloy coating for long-term outdoor protection.
- Chemical Acid Passivation: Stainless steel washers undergo nitric acid passivation to restore the chromium oxide anti-corrosion film.
Key Construction and Industrial Applications of Square Washers
Square plate washers are specified across applications where high load spreading or channel retention is required:
- Timber Construction & Heavy Wood Structures: Placed under carriage bolts or hex head lag screws on wooden post connectors, timber bridges, and roof trusses to prevent head pull-through.
- Strut Channel Framing & Modular Supports: Assembled inside or over strut channels to distribute clamping pressure over channel lips.
- Concrete Anchor Bolts & Foundation Plates: Installed over anchor bolts on concrete pads to secure structural steel column baseplates.
Quality Assurance and Export Packaging for Square Washers
Handan YiHao Fastener enforces strict Quality Assurance (QA) standards for all overseas export orders. Testing procedures include 100% inner/outer dimension verification, plate thickness micrometer testing, coating thickness gauge measurement, and salt spray validation.
All export items are bulk packed in heavy-duty 25kg inner cartons, neatly stacked on ISPM 15 compliant fumigated wooden pallets, and wrapped in protective stretch film for safe ocean freight.
Request Factory Direct Pricing for Square Washers
Looking for a trusted manufacturer in Handan, China for carbon steel or stainless steel square plate washers (DIN 436, DIN 434, DIN 435, Electro-Zinc, HDG)? Contact Handan YiHao Fastener today for technical datasheets, custom thickness plate samples, and direct bulk export quotes.
