External circlips, also known as external retaining rings, external snap rings, or circlips for shafts, are semi-circular spring steel fasteners designed to be mounted into a machined groove on the outside diameter of a shaft or cylindrical surface. Their primary function is to prevent mounted components such as bearings, gears, pulleys, or wheels from moving axially along the shaft, ensuring precise positioning and reliable operation under dynamic loads.
Applicable Standards
| Standard | Description |
|---|---|
| DIN 471 | External circlips (retaining rings for shafts) – metric series, nominal diameters 3mm to 200mm |
| GB/T 894 | Chinese national standard for external circlips (equivalent to DIN 471) |
| BS 3673-4:1977 | British standard specification for circlips (external and internal types) |
| ASME B18.27 | Inch series retaining rings (external and internal) for North American applications |
Materials & Surface Finishes
| Material | Properties | Surface Finish Options | Typical Applications |
|---|---|---|---|
| Spring Steel (65Mn, 60Si2MnA, C67S) | High strength, excellent flexibility, fatigue-resistant | Phosphate and oil (standard), black oxide, zinc plating | General industrial, automotive, machinery |
| Stainless Steel (304 / A2) | Good corrosion resistance, non-magnetic | Passivated, plain | Food processing, medical equipment, marine |
| Stainless Steel (316 / A4) | Superior corrosion resistance, suitable for harsh environments | Passivated, plain | Marine, chemical processing, coastal applications |
Common Applications
| Industry | Specific Applications |
|---|---|
| Automotive | Engines, transmissions, steering systems, drive shafts, suspension components |
| Industrial Machinery | Spindles, motors, turbines, pumps, gearboxes, conveyor systems |
| Aerospace | Aircraft components requiring reliable fastening and easy maintenance access |
| Agricultural Equipment | Tractors, harvesters, implements requiring robust, field-serviceable fasteners |
| Medical Devices | Stainless steel circlips for sterilizable and corrosion-resistant equipment |
| Electrical Motors | Rotor and bearing retention on motor shafts |
| Hydraulic & Pneumatic Systems | Piston rods, cylinder end caps, valve assemblies |








