ASTM F436 Flat Washer
ASTM F436 Flat Washers are hardened steel washers designed for use with high-strength bolts and structural fastening assemblies. Unlike standard flat washers, F436 washers are heat treated to achieve the required hardness and strength, allowing them to withstand high clamping loads while helping distribute the load over a larger bearing area.
The controlled hardness helps the washer resist deformation, embedding, and excessive surface indentation under heavy bolt preload. This makes ASTM F436 washers particularly suitable for demanding structural connections where the washer must maintain its shape and provide consistent load transfer between the bolt head or nut and the connected material. Available in different sizes and finishes, ASTM F436 Flat Washers can be matched with compatible high-strength structural bolts and nuts in steel structures, bridges, transmission towers, industrial equipment, and other heavily loaded bolted connections. The washer size, material, hardness, and surface treatment should be selected according to the bolt assembly and service conditions.
Specification:
ASTM F436 Flat Washers are hardened steel washers manufactured to specified requirements for material, hardness, dimensions, and performance. They are available in carbon steel and weathering steel types, with inch and metric dimensions depending on the applicable F436 or F436M specification.
The washers are heat treated to provide the hardness required for high-strength bolted connections. Through-hardened washers have a hardness of 38–45 HRC, while hot-dip galvanized through-hardened washers have a specified hardness range of 26–45 HRC.
| Item | Specification |
|---|---|
| Standard | F436/F436M |
| Product Type | Hardened Flat Washer |
| Dimension System | Inch/Metric |
| Size Range | 1/4"-4" |
| Heat Treatment | Quenching and tempering |
| Material | C45 Medium Carbon Steel |
| Surface Treatment | Plain,Zinc Plated,Hot Dip Galvanized |
| Hardness | 38-45HRC |
| Hardness-HDG | HDG: 26-45HRC |
- RELATED WASHER LISTS:
- DIN125 Flat Washer
- DIN127 Spring Lock Washer
- DIN9021 Large Washer
- ASME/ANSI B 18.21.1 (USS) Flat Washer
- ASME/ANSI B 18.21.1 (SAE) Flat Washer
- ASME/ANSI B18.21.1 Helical Spring-Lock Washer
- DIN25201 Stainless Steel Double Fold Self-locking Washer
- DIN6797A Stainless Steel External Teeth Lock Washers
- Stainless Steel DIN6797J Internal Teeth Lock Washers
Dimension Chart of ASTM F436 Steel Washer:
The dimension chart provides the key dimensions required to select ASTM F436 hardened flat washers for high-strength bolted connections. Inside diameter, outside diameter, and washer thickness determine compatibility with the bolt and the available bearing area. The washer dimensions should be matched with the corresponding bolt, nut, and structural connection.
| Diameter | 1/4 | 5/16 | 3/8 | 7/16 | 1/2 | 5/8 | 3/4 | 7/8 | 1 | 1-1/8 | 1-1/4 | 1-3/8 | 1-1/2 | 1-3/4 | 2 | 2-1/4 | 2-1/2 | 2-3/4 | 3 | 3-1/4 | 3-1/2 | 3-3/4 | 4 |
| dc | 0.625 | 0.688 | 0.813 | 0.922 | 1.063 | 1.313 | 1.469 | 1.750 | 2.000 | 2.250 | 2.500 | 2.750 | 3.000 | 3.375 | 3.750 | 4.000 | 4.500 | 5.000 | 5.500 | 6.000 | 6.500 | 7.000 | 7.500 |
| d min | 0.281 | 0.344 | 0.406 | 0.469 | 0.531 | 0.688 | 0.813 | 0.938 | 1.125 | 1.250 | 1.375 | 1.500 | 1.625 | 1.875 | 2.125 | 2.375 | 2.625 | 2.875 | 3.125 | 3.375 | 3.625 | 3.875 | 4.125 |
| h min | 0.051 | 0.051 | 0.051 | 0.051 | 0.097 | 0.122 | 0.122 | 0.136 | 0.136 | 0.136 | 0.136 | 0.136 | 0.136 | 0.178 | 0.178 | 0.240 | 0.240 | 0.240 | 0.240 | 0.240 | 0.240 | 0.240 | 0.240 |
| h max | 0.080 | 0.080 | 0.080 | 0.080 | 0.177 | 0.177 | 0.177 | 0.177 | 0.177 | 0.177 | 0.177 | 0.177 | 0.177 | 0.280 | 0.280 | 0.340 | 0.340 | 0.340 | 0.340 | 0.340 | 0.340 | 0.340 | 0.340 |
Application of F436 hardened circular washer:
Structural Steel Connections
ASTM F436 hardened washers are widely used with high-strength structural bolts in steel buildings, bridges, steel frames, and fabricated structures. Their hardened construction helps resist deformation under high bolt preload while distributing the clamping load over the connected surface.
Transmission Towers & Utility Structures
F436 washers are suitable for transmission towers, substations, utility structures, and other outdoor steel assemblies where high-strength bolted connections are exposed to substantial mechanical loads. Hot-dip galvanized versions can provide additional corrosion protection for outdoor service.
Heavy-Duty Industrial Equipment
These washers can also be used in industrial machinery, heavy equipment, structural supports, pressure-related equipment, and heavily loaded mechanical assemblies where a hardened washer is required to maintain bearing performance under high clamping forces.