# item.guide
Side-by-Side Comparison Washers & Retaining Rings

Belleville Washers vs. Flat Washers

Comparing 2 standards across 17 specifications. 17 key differences identified.

Comparing:
Belleville Washers
Flat Washers

The Belleville Washer (Conical Disc Spring / Cupped Spring Washer, standardized under DIN 2093 and DIN 6796) is a conical annular spring disc engineered to deliver massive axial spring clamping force across sub-millimeter deflection distances, maintaining bolted joint tension under extreme thermal expansion and dynamic vibration.

View full Belleville Washers spec sheet →

Standard flat washers distribute fastener clamp load and prevent surface embedding, standardized under DIN 125 (ISO 7089 Form A metric without chamfer) and ASME B18.22.1 (Type A Narrow, Regular, and Wide series in imperial sizes).

View full Flat Washers spec sheet →

Specification Comparison Table

17 Parameters
Parameter / Spec
Standard Specifications
DIN 2093 (Precision disc springs) / DIN 6796 (Heavy-duty bolted joints) / ISO 19643
Conical Geometry
Frusto-conical cup shape (cone height ≈ 0.5× to 0.7× disc thickness)
Load Capacity
Extreme axial spring force (thousands of newtons in sub-millimeter stroke)
Stacking Capabilities
Parallel Stacking (nests together to multiply load) or Series Stacking (tips touch to multiply deflection)
Standard Materials
51CrV4 chrome-vanadium spring steel / 17-7 PH stainless / Inconel 718 (high temp)
Primary Applications
High-voltage electrical busbars, engine cylinder heads, cryogenic piping, wind turbine bolts
Governing Standards
DIN 125 Form A (ISO 7089) / ASME B18.22.1 Type A
M3 Flat Washer
ID: 3.2 mm | OD: 7.0 mm | Thickness: 0.5 mm
M4 Flat Washer
ID: 4.3 mm | OD: 9.0 mm | Thickness: 0.8 mm
M5 Flat Washer
ID: 5.3 mm | OD: 10.0 mm | Thickness: 1.0 mm
M6 Flat Washer
ID: 6.4 mm | OD: 12.0 mm | Thickness: 1.6 mm
M8 Flat Washer
ID: 8.4 mm | OD: 16.0 mm | Thickness: 1.6 mm
M10 Flat Washer
ID: 10.5 mm | OD: 20.0 mm | Thickness: 2.0 mm
M12 Flat Washer
ID: 13.0 mm | OD: 24.0 mm | Thickness: 2.5 mm
1/4" ASME Type A
ID: 0.281 in (7.1 mm) | OD: 0.625 in (15.9 mm) | Thickness: 0.065 in (1.65 mm)
3/8" ASME Type A
ID: 0.406 in (10.3 mm) | OD: 0.812 in (20.6 mm) | Thickness: 0.065 in (1.65 mm)
1/2" ASME Type A
ID: 0.531 in (13.5 mm) | OD: 1.062 in (27.0 mm) | Thickness: 0.095 in (2.41 mm)