Standard:USS
Description:
USS washers, also known as plain washers, are commonly used in the United States and are specified by the Unified Screw Thread Standard (USS). They are used to distribute the load and provide a larger bearing surface when used with bolts or screws. The size range you mentioned, 1/4" to 3", refers to the nominal diameter of the bolt or screw they are designed to work with.
When specified with a "Black Oxide" finish, USS washers have undergone a surface treatment process known as black oxide coating. Black oxide coating, also known as blackening, is a conversion coating that creates a thin layer of black oxide on the surface of the washer.
The black oxide coating serves multiple purposes. First, it provides a degree of corrosion resistance, although its level of protection may not be as high as that of other coatings like hot-dip galvanizing or zinc plating. Second, the black oxide finish enhances the aesthetics of the washers, giving them a sleek black appearance. Lastly, the black oxide layer can improve the wear resistance and lubricity of the washers, facilitating smooth assembly and operation.
USS washers with a black oxide finish are commonly used in various applications where both functionality and visual appeal are important. They find applications in industries such as automotive, machinery, and general manufacturing.
Please note that while black oxide coating provides some corrosion resistance, it may not offer the same level of protection as other specialized coatings. If high levels of corrosion resistance are required, alternative coatings or finishes, such as hot-dip galvanizing or zinc plating, may be more suitable.
| Material | 45#/40CR |
| Size | 1/4"-3" |
| Finish | Plain/black/ZINC/HDG/Dacromet/Mechanical Galvanized |
| Hardness | HV300/HRC35-45 |
| Marking | can be Customized |
| Application | Constrution/Wind turbines/railway line |
| Packing | Carton+ pallet; we can pack washers as your requirements |
| Terms | FOB+shanghai/ningbo |
| Delivery time | 30-70days |
| Size |
Inner diamater (max) |
Inner diamater (min) |
Outside diamater (max) |
Outside diamater (min) |
Thickness (max) |
Thickness (min) |
| 3/16" |
14.66 |
14.15 | 6.73 | 6.22 | 1.65 | 0.91 |
| 1/4" | 19.02 | 18.47 | 8.31 | 7.8 | 2.03 | 1.3 |
| 5/16" | 22.99 | 22.05 | 9.91 | 9.4 | 2.64 | 1.63 |
| 3/8" | 26.16 | 25.22 | 11.51 | 11 | 2.64 | 1.63 |
| 7/16" | 32.51 | 31.57 | 13.08 | 12.57 | 2.64 | 1.63 |
| 1/2" | 35.69 | 34.57 | 14.66 | 14.15 | 3.35 | 2.18 |
| 9/16" | 38.07 | 37.13 | 16.25 | 15.75 | 3.35 | 2.18 |
| 5/8" | 45.21 | 44.27 | 18.24 | 17.3 | 4.06 | 2.74 |
| 3/4" | 51.56 | 50.62 | 21.39 | 20.45 | 4.5 | 3.1 |
| 7/8" | 57.91 | 56.97 | 24.58 | 23.65 | 4.88 | 3.45 |
| 1" | 64.26 | 63.32 | 27.74 | 26.8 | 4.88 | 3.45 |
| 1-1/8" | 70.61 | 69.67 | 32.51 | 31.57 | 4.88 | 3.45 |
| 1-1/4" | 76.96 | 76.02 | 35.69 | 34.75 | 4.88 | 3.45 |
| 1-3/8" | 83.69 | 82.3 | 39.24 | 37.85 | 5.41 | 3.45 |
| 1-1/2" | 90.04 | 88.65 | 42.42 | 41.02 | 5.41 | 3.45 |
| 1-5/8" | 96.39 | 95 | 45.59 | 44.2 | 5.41 | 3.89 |
| 1-3/4” | 102.74 | 101.35 | 48.77 | 47.37 | 5.41 | 3.89 |
| 1-7/8“ | 109.09 | 107.7 | 51.94 | 50.55 | 5.41 | 3.89 |
| 2” |
115.44 |
114.05 | 55.12 | 53.72 | 5.41 | 3.89 |
| 2-1/4“ | 121.79 | 120.4 | 61.47 | 60.07 | 6.3 | 4.9 |
| 2-1/2” | 128.14 | 126.75 | 67.82 | 66.42 | 7.11 | 5.33 |
| 2-3/4“ | 135 | 133.1 | 74.68 | 72.77 | 7.87 | 5.79 |
| 3” | 141.35 | 139.45 | 81.03 | 79.12 | 8.31 | 6.32 |
Products pictures for Flat washers
