Circlips
What are Circlips?
Circlips (also known as snap rings or retaining rings) are semi-flexible metal rings used to secure components onto a shaft or inside a housing/bore, preventing lateral movement.
Commonly used in mechanical assemblies, gear systems, and bearing retention, circlips are critical for axial load control in rotating or static applications. They are quick to install, space-saving, and highly reliable under dynamic conditions.
Key Features
Secure
Retention
Durable
Construction
Easy Installation
& Removal
Wide
Compatibility
Corrosion
Resistant
Specifications
| Specification Category | Parameter / Feature | Details / Options |
|---|---|---|
| Size Range | Standard Sizes | 3 mm to 400 mm (shaft or bore diameter) |
| Types of Circlips | Internal Circlip (DIN 472) | Fits into grooves inside a bore/housing |
| External Circlip (DIN 471) | Fits onto grooves on a shaft | |
| E-Clips | Quick assembly, used in medium-load applications | |
| Snap Rings | Used for light-to-medium loads, easy to install/remove | |
| Material Options | Spring Steel (Carbon Steel) | Most common, high strength and durability |
| Stainless Steel (SS304, SS316) | Corrosion resistance for marine/chemical use | |
| Phosphor Bronze | Non-magnetic, good wear resistance | |
| Beryllium Copper | Non-sparking, excellent fatigue resistance | |
| Surface Finish / Coating | Standard | Phosphate coated, Black oxide finish |
| Optional Coatings | Zinc plated, Cadmium plated, Passivated for stainless steel | |
| Standards & Certifications | International Standards | DIN 471 (External), DIN 472 (Internal), IS 3075, BS 3673, ANSI B27.7 |
| Certifications | ISO 9001, IATF 16949 (for automotive), RoHS compliant | |
| Design Features | Thickness Range | 0.5 mm to 6 mm depending on diameter |
| Groove Fit | Designed for precise groove fit to prevent axial movement | |
| Retaining Strength | High radial force for secure retention | |
| Testing & Inspection | Dimensional Testing | Vernier, micrometer, go/no-go gauges |
| Mechanical Testing | Hardness (Rockwell C), Tensile strength | |
| Surface Testing | Coating thickness, Salt spray corrosion test |
Dimensions of External Circlips (DIN 471)
| Nominal Shaft Diameter (d1) | Circlip Thickness (s) | Groove Diameter (d2) | Groove Width (m) | Groove Depth (t) | Free Diameter (d3 max.) |
|---|---|---|---|---|---|
| 10 mm | 0.8 mm | 9.4 mm | 1.0 mm | 0.35 mm | 11.2 mm |
| 15 mm | 1.0 mm | 14.4 mm | 1.2 mm | 0.45 mm | 16.5 mm |
| 20 mm | 1.2 mm | 19.4 mm | 1.5 mm | 0.55 mm | 21.8 mm |
| 25 mm | 1.5 mm | 24.4 mm | 1.8 mm | 0.65 mm | 27.0 mm |
| 30 mm | 1.75 mm | 29.4 mm | 2.0 mm | 0.75 mm | 32.5 mm |
| 40 mm | 2.0 mm | 39.4 mm | 2.4 mm | 0.95 mm | 43.0 mm |
| 50 mm | 2.5 mm | 49.4 mm | 3.0 mm | 1.20 mm | 54.0 mm |
| 60 mm | 3.0 mm | 59.4 mm | 3.5 mm | 1.40 mm | 65.0 mm |
| 80 mm | 3.5 mm | 79.4 mm | 4.0 mm | 1.60 mm | 86.0 mm |
| 100 mm | 4.0 mm | 99.4 mm | 4.5 mm | 1.80 mm | 108.0 mm |
Dimensions of Internal Circlips (DIN 472)
| Nominal Bore Diameter (D1) | Circlip Thickness (s) | Groove Diameter (D2) | Groove Width (m) | Groove Depth (t) | Free Diameter (D3 min.) |
|---|---|---|---|---|---|
| 10 mm | 0.8 mm | 10.6 mm | 1.0 mm | 0.35 mm | 8.8 mm |
| 15 mm | 1.0 mm | 15.6 mm | 1.2 mm | 0.45 mm | 13.2 mm |
| 20 mm | 1.2 mm | 20.6 mm | 1.5 mm | 0.55 mm | 17.5 mm |
| 25 mm | 1.5 mm | 25.6 mm | 1.8 mm | 0.65 mm | 22.0 mm |
| 30 mm | 1.75 mm | 30.6 mm | 2.0 mm | 0.75 mm | 26.5 mm |
| 40 mm | 2.0 mm | 40.6 mm | 2.4 mm | 0.95 mm | 36.0 mm |
| 50 mm | 2.5 mm | 50.6 mm | 3.0 mm | 1.20 mm | 45.0 mm |
| 60 mm | 3.0 mm | 60.6 mm | 3.5 mm | 1.40 mm | 54.0 mm |
| 80 mm | 3.5 mm | 80.6 mm | 4.0 mm | 1.60 mm | 72.0 mm |
| 100 mm | 4.0 mm | 100.6 mm | 4.5 mm | 1.80 mm | 90.0 mm |
Mechanical Properties
| Property | Value | Unit / Standard |
|---|---|---|
| Tensile Strength | 600 – 1200 | MPa (depends on material: Spring Steel, SS 304/316, Alloy Steel) |
| Yield Strength | 420 – 1000 | MPa |
| Hardness | 430 – 600 | HV (Vickers) / 44 – 55 HRC |
| Elongation | ≥ 5 – 12 | % |
| Density | 7.8 – 8.0 | g/cm³ |
| Impact Toughness | ≥ 20 – 50 | J (Charpy, varies with grade) |
| Modulus of Elasticity (E) | ~200 | GPa |
| Fatigue Strength | 300 – 600 | MPa |
| Corrosion Resistance | Good to Excellent | (phosphated, oil-coated, or SS grades) |
| Thermal Conductivity | 15 – 50 | W/m·K |
| Coefficient of Thermal Expansion | 11 – 17 ×10⁻⁶ | /°C |
| Yield Ratio (YS/UTS) | 0.65 – 0.85 | – |
| Poisson’s Ratio | 0.27 – 0.30 | – |
| Hardness Range | 44 – 55 | HRC (heat-treated) |
| Surface Finish | Phosphated, Oil-dipped, Black oxide, Polished SS | – |
| Operating Temperature Range | -50 to 300 | °C |
| Standards Covered | DIN 471 (External), DIN 472 (Internal), ISO, ASTM | – |
Chemical Composition
| Element | SS 304 | SS 304L | SS 316 | SS 316L |
|---|---|---|---|---|
| Chromium (Cr) | 18.0 – 20.0 | 18.0 – 20.0 | 16.0 – 18.0 | 16.0 – 18.0 |
| Nickel (Ni) | 8.0 – 10.5 | 8.0 – 12.0 | 10.0 – 14.0 | 10.0 – 14.0 |
| Carbon (C) | ≤ 0.08 | ≤ 0.03 | ≤ 0.08 | ≤ 0.03 |
| Manganese (Mn) | ≤ 2.00 | ≤ 2.00 | ≤ 2.00 | ≤ 2.00 |
| Silicon (Si) | ≤ 1.00 | ≤ 1.00 | ≤ 1.00 | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.045 | ≤ 0.045 | ≤ 0.045 | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 | ≤ 0.030 | ≤ 0.030 | ≤ 0.030 |
| Iron (Fe) | Balance | Balance | Balance | Balance |
| Molybdenum (Mo) | — | — | 2.0 – 3.0 | 2.0 – 3.0 |
Applications of Circlips
Construction &
Infrastructure
Automotive & Heavy
Equipment
Manufacturing &
Fabrication
Medical & Laboratory
Equipment
Electrical &
Electronics Assembly
Oil, Gas & Petrochemical
Installations
Do you have questions?
What’s the difference between internal and external circlips?
Are circlips reusable?
Can I get custom circlips in non-standard sizes?
Are stainless steel circlips available for corrosive environments?
