Washers
What are Washers ?
A washer is a thin plate (typically disk-shaped) with a hole (typically in the middle) that is normally used to distribute the load of a threaded fastener, such as a screw or nut. Other uses are as a spacer, spring (belleville washer, wave washer), wear pad, preload indicating device, locking device, and to reduce vibration (rubber washer). Washers usually have an outer diameter (OD) about twice the width of their inner diameter (ID).
Washers are usually metal or plastic. High quality bolted joints require hardened steel washers to prevent the loss of pre-load due to Brinelling after the torque is applied.
Rubber or fiber gaskets used in taps (or faucets, or valves) to stop the flow of water are sometimes referred to colloquially as washers; but, while they may look similar, washers and gaskets are usually designed for different functions and made differently.
Washers are also important for preventing galvanic corrosion, particularly by insulating steel screws from aluminium surfaces.
There are vairous types of Washers viz :
| Plain Washers | Split Washers | Square Washers |
| Spring Washers | Nord Lock Washers | Disc Spring Washers |
| Internal Tooth Washers | External Tooth Washers | Dock Washers |
| Ogee Washers | Torque Washers | Fender Washers |
| Wave Washers | Belleville Washers | Hexagonal Washers |
| Plate Washer | Taper Washer | Nylon Washer |
| Serrated Washer | Teeth Washer | Friction Washer |
| Tension Disk Washer | Flat Washers | Split Lock Washers |
| Finish Washers | Flange Finish Washers | Special Washers |
| Lock Washers | Beveled Washers | Finishing Washers |
| Bonded Sealing Washers | Hillside Washers | Conical Washers |
| Spherical Washers | Wave Washers | Round-Mall Washers |
| Saddle Washers | SAE Flat Washers | USS Flat Washers |
| Commercial Flat Washers |
Applications
| Construction | Railways | Scaffolding | Bridges | Marine |
| Oil & Gas | Light / Heavy Industries | Structural | Power Plates | Civil |
Types
- Cold Forged Fasteners, Hot Forged Fastener, C-Machined Hex Head Bolts, CNC Machined Hex Head Bolts, Custom Machined Hex Head Bolts, Threaded Hex Head Bolts, Non-Threaded Hex Head Bolts, Bar Stock Machined Hex Head Bolts.
Size Range
- Metric Range from M1.0 to M100 and Imperial Range from 1/16 inch to 4 inch.
Threads
- Coarse, Fine, UNC, UNF, UN, BSW, Acme Threads with Half Thread, Full Thread & Double End Thread Configuration.
Services
| Electro Zinc Plating | Hot Dip Galvanizing | Ptfe Fluorocarbon Coating |
| Aluminizing | Ceramic Filled Fluorocarbon Coating | Nickel Plating |
| Mechanical Zinc Coating | Electro Zinc Colbalt Plating | Electro Zinc Nickel Plating |
| Phosphate Coating | Electro Less Nickel Plating | Electro Cadmium Plating |
| Dacromet 320 500 Coating | Pickled Passivated Fasteners | Silver Plating |
| Zinc Plating | Mechanical Galvanization | ZN Phosphating |
| MN Phosphating | Cadium Plating | Zinco-Nickel Plating |
| Nickel Electroless Plating | Burnishing | Geomet |
| Customised Coating | Ceramic Filled Fluorocarbon Coating |
Dimensional Standards
- Materials – ASTM / ASME / BSI / ISO / Nace / AFNOR / DIN / AISI
- Hexagonal Bolts – ANSI B18.2.1, ANSI B18.2.3.1M, DIN 931, DIN 933, BS 1768, UNI 5731, UNI 5737, UNI 5739, ISO 4014, ISO 4017, BS 1769, BS 3692
- Socket/Slotted Set Screws – DIN 913, DIN 914, DIN 915, DIN 916, DIN 551, DIN 553, DIN 438, BS 4168
- Socket/Slotted Countersunk Screws – DIN 963, DIN 7991, BS 4168, BS 1981, BS 483, BS 2470
- Socket Cap Screws – ANSI B18.3, B18.3.1M, DIN 912, DIN 6912, DIN 7984, ANSI B18.3, ISO 4762, UNI 5931, BS 2470, BS 4168
- Stud Bolts – ASME B18.2.1, DIN 976, DIN 938, DIN 939, DIN 2510, BS 4439, BS 2693, BS4882
- Nuts – ANSI B18.2.2, ANSI B18.2.4.6M, DIN 934, DIN 936, BS 1768, BS 1769, BS 1083, BS 3692, ISO 4032, ISO 4033, ISO 4035, UNI 5587, UNI 5588, UNI 5589
- Washers – ASME B18.22.1, ASTM F436, ISO 7089, DIN 125, DIN 9021, BS 4320, BS 3410, DIN 127, BS 4464, BS 1802, UNI 6952
- Common Grades – SAE J429 Gr 5, SAE J429 Gr 8, ASTM A307 Gr A, ASTM A307 Gr B, ASTM A325 Type 1, ASTM A490 Type 1, ASTM A193 Gr B7, ASTM A193 Gr B7M, ASTM A193 Gr B16, ASTM A193 G B8, ASTM A320 Gr L7, ASTM A193 G B8M, BS 3692 Gr 4.8, BS 3692 8.8, BS 3692 Gr 10.9, BS 3692 12.9, JIS B1188 Class F8T, JIS B1185 Class F10T, SS304, SS316, SS316L, BS EN ISO 3506 A2-50, BS EN ISO 3506 A2-70, BS EN ISO 3506 A2-80, BS EN ISO 3506 A4-50, BS EN ISO 3506 A4-70, BS EN ISO 3506 A4-80