What Are Disc Springs (Belleville Springs)?

A disc spring, also called a Belleville spring or Belleville washer, is a conical ring of steel that generates a predictable load when compressed. The geometry is simple. The behavior is not. That small cone is the reason these springs sit inside aircraft landing gear, automotive clutch packs, pipeline flanges, and nuclear valve actuators all over the world.

The Basics: What Exactly Is a Disc Spring?

Picture a flat washer, then press the center down so it forms a shallow cone.

That cone, loaded along its axis, stores elastic energy the same way a coil spring does, but in a fraction of the height.

Four parameters describe every disc spring: outer diameter (De), inner diameter (Di), free height (Lo), and material thickness (t).

The single most important design value is the ratio of free cone height (ho) to thickness (t), written as h/t.

That one ratio decides whether the spring feels stiff, soft, or nearly constant under load.

Disc springs follow two European standards worldwide. DIN EN 16983 (formerly DIN 2093) covers dimensions, tolerances, and quality requirements. DIN EN 16984 (formerly DIN 2092) covers the calculation methods.

Both standards define three series, A, B, and C, for each outer diameter, with each series carrying a different load level.

A spring labeled A50, for example, is a Series-A spring with a 50 mm outer diameter at the highest load rating for that size.

How Disc Springs Work

Compress a disc spring along its axis and the cone flattens, storing elastic energy as it goes.

The force comes back out concentrically.

No bending moment, no side load — that is the one thing a coil spring can never quite do, and it is why disc springs win in tight, heavily loaded joints where a coil would push sideways and bind.

The h/t ratio is the lever that changes the entire character of the spring.

As that ratio climbs, the load-deflection curve moves away from a straight line and starts to flatten.

This relationship is well established in the engineering literature and confirmed in disc spring design references:

That near-constant force region in the middle of the range is the useful part.

Disc Springs vs.Coil Springs: When to Choose Which

It is also why a spring with a high h/t ratio needs a guide shaft or sleeve.

Left unsupported, it can push through or flip.

When you need long, smooth travel, rarely.Picking the wrong one here is a common cause of field failures, so it is worth being honest about the trade-offs.

The real flexibility of disc springs comes from stacking.

Combining springs in different orientations produces very different load-deflection profiles from the same standard part.

Mixing both methods, with some springs in parallel and groups of those connected in series, lets engineers reach almost any load-deflection curve from one standard part.

This is a major reason disc springs are so common in precision equipment: a single catalog ring can be configured for a wide range of load and travel targets without tooling up a custom part.

Disc Springs vs. Coil Springs: When to Choose Which

For corrosive or cryogenic service down to about −200°C, the common choices are stainless grades X12CrNi 17 7 (DIN 1.4310), used up to around 1.25 mm thick, and X7CrNiAl 17 7 (DIN 1.4568) for thicker discs, which leading makers rate for excellent corrosion resistance and high-temperature use up to around 600°C.

When space is tight and the load is high, almost always.

When you need long, smooth travel, rarely. Picking the wrong one here is a common cause of field failures, so it is worth being honest about the trade-offs.

The table below lays out the factors that usually decide it.

Materials and Surface Treatments

Material is where good designs quietly go wrong.

The base steel sets the temperature range, the corrosion resistance, and the fatigue life all at once, so a choice made to save a few cents on the strip can surface years later as a cracked spring in a place nobody wants to open up.

Carbon and alloy steel, typically 51CrV4 to EN 10089, retains its elasticity for sustained service up to roughly 300°C, with some manufacturers rating it higher for short excursions.

For corrosive or cryogenic service down to about −200°C, the common choices are stainless grades X12CrNi 17 7 (DIN 1.4310), used up to around 1.25 mm thick, and X7CrNiAl 17 7 (DIN 1.4568) for thicker discs, which leading makers rate for excellent corrosion resistance and high-temperature use up to around 600°C.

The most demanding turbine and power-generation work moves into nickel-base alloys.

Surface treatment matters too.

Phosphate and oil is the standard finish, giving basic corrosion protection and helping the spring retain lubricant.

Shot peening induces compressive residual stress at the surface, which reduces the tensile stresses that usually start fatigue cracks.

Manufacturer design guides recommend it specifically for dynamically loaded springs where fatigue life is the priority.

Where Disc Springs Are Used

The disc spring's core advantage is high force in very little axial space.

That makes it hard to replace in one class of engineering problem: tight packaging combined with heavy loads and a need for consistent behavior over many cycles.

Analysts consistently name automotive, aerospace, and industrial machinery as the largest end-use sectors, with oil and gas, power generation, and construction close behind.

Selecting the Right Disc Spring: A Practical Framework

You cannot pick a disc spring straight off a chart.

Start with what the joint actually needs — load and travel — then work backward through geometry, material, and stacking.

The four steps below are the order most engineers follow.

Step 1: Define the load and deflection envelope

What is the minimum load the joint must hold, and the maximum it must not exceed?

Keep stacks as short as practical.In long stacks, friction causes the discs at the moving end to over-deflect while those at the far end under-deflect.

Those numbers constrain every later decision.

A widely used design rule limits working deflection to 75% of the free cone height (ho).

Beyond that point, force and stress climb sharply, which shortens fatigue life.

Step 2: Choose a stacking strategy

If load is the limiting factor and travel is available, stack in parallel.

If travel is the constraint, stack in series.

Hybrid stacks, groups of parallel discs joined in series, handle cases where both load and travel exceed what a single disc can deliver.

Keep stacks as short as practical. In long stacks, friction causes the discs at the moving end to over-deflect while those at the far end under-deflect.

Step 3: Select material and finish

Match the operating temperature, corrosion environment, and any magnetic requirement to the material.

Do not default to carbon steel just because it costs less.

The wrong material on a subsea valve can cost far more in downtime than the price gap between spring grades.

Step 4: Verify against the standard

Group 1 covers discs under 1.25 mm, cold formed with radiused edges and no contact flats.

Group 2 runs from 1.25 mm up to and including 6 mm, cold formed or fine-blanked and machined.

Pre-set (scragged) springs, which are compressed flat during manufacture so that non-recovering units can be discarded, perform more predictably in dynamic service.

Standards and Compliance

Two standards run the show here, and if you have seen older drawings you will still recognise their German ancestors.

DIN 2092 and DIN 2093 were withdrawn on 1 February 2017 and folded into the European standards below.

The technical content did not change — only the numbers on the cover did — so a part called out to the old DIN is the same part under the new EN.

Yes.They are the same component under different names."Disc spring" is the term used in European standards such as DIN EN 16983, while "Belleville washer" or "Belleville spring" is the common North American term, named after French engineer Julien Belleville, who patented the conical spring concept in 1867.All refer to a conical ring loaded along its axis.

Group 1 covers discs under 1.25 mm, cold formed with radiused edges and no contact flats.

As a disc spring compresses toward flat, its cone angle drops and the effective lever arm shortens, which changes stiffness through the stroke.A low h/t ratio keeps this effect small, so the curve stays nearly straight.A higher ratio makes the effect dominant, producing a regressive curve and, in the middle of the range, a region of near-constant force.This is geometry, not material choice, which is why the same steel can give very different curves at different h/t ratios.

Group 3 covers discs over 6 mm up to 14 mm, which the standard recommends be made with contact flats.

There is no fixed limit, but practical factors set the ceiling.Long parallel stacks need an internal guide shaft or external sleeve to prevent buckling, and friction between discs grows with stack height, which reduces load accuracy.Many designers add disc separators in long stacks and keep stacks as short as the load and travel targets allow, because shorter stacks deflect more evenly under dynamic loading.

A Group 3 disc cannot be held to Group 1 tolerances.

The four most common causes are exceeding the 75% deflection guideline in dynamic service, picking the wrong material for the temperature or chemical environment, running a stacked assembly without lubrication so the contact surfaces gall, and compressing a spring flat during installation, which plastically deforms it and shifts its load curve for good.Springs should never be torqued flat as an assembly method.

Are disc springs and Belleville washers exactly the same component?

Yes, with the right material.Standard carbon and alloy steel grades such as 51CrV4 retain their spring properties for sustained service up to around 300°C.For higher temperatures, precipitation-hardened stainless steels such as X7CrNiAl 17 7 (DIN 1.4568) are preferred and are rated by leading makers up to around 600°C.The most extreme turbine and power-generation work moves into nickel-base alloys.At high temperature, relaxation, the gradual loss of load under sustained compression, speeds up and must be built into the design allowance.

Why does the load-deflection curve change with the h/t ratio?

The single-spring load-deflection relationship comes from the formulas in DIN EN 16984, which use outer diameter, inner diameter, cone height, thickness, and the material's elastic modulus.For a parallel stack, total load is roughly the single-spring load times the number of discs.For a series stack, total deflection is the single-spring deflection times the number of discs at the same load.Most manufacturers provide calculators based on these formulas, and FEA software can validate complex hybrid stacks.

How many disc springs can be stacked together?

This article is written for engineering and procurement professionals.Always verify spring selection against the full DIN EN 16983 and DIN EN 16984 standards, and consult a qualified engineer for safety-critical applications.

What causes a disc spring to fail early?

The four most common causes are exceeding the 75% deflection guideline in dynamic service, picking the wrong material for the temperature or chemical environment, running a stacked assembly without lubrication so the contact surfaces gall, and compressing a spring flat during installation, which plastically deforms it and shifts its load curve for good. Springs should never be torqued flat as an assembly method.

Can disc springs be used above 300°C?

Yes, with the right material. Standard carbon and alloy steel grades such as 51CrV4 retain their spring properties for sustained service up to around 300°C. For higher temperatures, precipitation-hardened stainless steels such as X7CrNiAl 17 7 (DIN 1.4568) are preferred and are rated by leading makers up to around 600°C. The most extreme turbine and power-generation work moves into nickel-base alloys. At high temperature, relaxation, the gradual loss of load under sustained compression, speeds up and must be built into the design allowance.

How is the load of a disc spring stack calculated?

The single-spring load-deflection relationship comes from the formulas in DIN EN 16984, which use outer diameter, inner diameter, cone height, thickness, and the material's elastic modulus. For a parallel stack, total load is roughly the single-spring load times the number of discs. For a series stack, total deflection is the single-spring deflection times the number of discs at the same load. Most manufacturers provide calculators based on these formulas, and FEA software can validate complex hybrid stacks.

References and further reading: Wikipedia, Belleville washer · DIN EN 16983 standard, available via Beuth Verlag · U.S. Patent and Trademark Office, Belleville spring guide system (US8366082B2)

This article is written for engineering and procurement professionals. Always verify spring selection against the full DIN EN 16983 and DIN EN 16984 standards, and consult a qualified engineer for safety-critical applications.