Key Takeaways

•   Disc springs (also called belleville springs, conical washers, and disc spring washers) solve clamp load loss in bolted connections caused by vibration, thermal expansion, and gasket creep.
•   Stacking in series multiplies deflection while load stays constant. Stacking in parallel multiplies the load while deflection stays constant.
•   Material selection depends on temperature and corrosion: carbon steel to 250°F, alloy steel to 480°F, 17-4 PH stainless steel to 700°F, and Inconel 718 above 900°F.
•   Specify OD, ID, free height, working height, load at deflection, temperature range, and environment before requesting a quote.
•   Request a quote with drawings and operating conditions for fast, accurate disc spring selection.

The Clamp Load Problem Disc Springs Solve

Bolt preload drops over time. Gasket relaxation steals 0.2 to 0.3 mm of extension. Thermal growth shifts joint dimensions. Vibration works fasteners loose in ASME B16.5 flanges, valve packing followers, and structural joints.

A disc spring stack under the nut or follower absorbs these changes. It keeps clamp force within a tight band even when temperature swings between about −40°F and 900°F, depending on the material. Design and maintenance engineers specify disc springs to cut retorque intervals on high-cycle bolted applications.

This article covers when to use springs in this family, how to stack them, what materials fit your environment, and what data you need before you request a quote.

 

What Is a Disc Spring (Belleville Spring)?

A disc spring is a conical washer that deflects under axial load and stores mechanical energy. Standard sizes follow DIN 2093, with outside diameters ranging from about 8 mm up to 250 mm in the DIN catalog. Belleville International manufactures disc springs from 0.500″ to over 42″ O.D., including custom sizes outside the standard range. Free height-to-thickness ratios (h0/t) run from 0.4 to 1.8. Loads span from a few hundred newtons on small sizes to hundreds of kilonewtons on large Series C parts.

DIN 2093 Series Designations

DIN 2093 divides disc springs into three series:

•   Series A: light, narrow cross-section, larger deflection.
•   Series B: medium cross-section, balanced load and deflection.
•   Series C: heavy cross-section, high load, lower deflection.

A DIN 2093 Series C disc with 63 mm OD and 2 mm thickness can deliver around 100 kN.

How Disc Springs Compare to Flat and Wave Washers

Flat washers offer negligible spring effect. They spread load and protect surfaces, but do not compensate for joint relaxation. Wave spring washers provide lower load and longer travel for the same deflection requirements, making them suited for moderate force and offering smoother characteristics.

Disc springs are also called Belleville washers, Belleville disc springs, conical spring washers, and disc spring washers. Treat these names as equivalent when searching catalogs and standards.

How Disc Springs Generate and Maintain Load

The conical geometry produces a nonlinear load-deflection curve. Engineers tune the free height-to-thickness ratio (h0/t) to match joint requirements.

Understanding the h0/t Ratio

•   Higher h0/t (around 1.8): progressive curve where load rises quickly at the end of travel. Useful when you want a rising rate.
•   h0/t near 1.41: relatively flat force region where load changes little over a sizable deflection band.

The flat region matters for bolted connections. In flange joints, gasket creep may reduce bolt extension by 0.2 to 0.3 mm over time, and Belleville Spring Flange Washers can enhance joint elasticity and reduce flange emissions. A disc spring stack with a flat portion of the curve delivers nearly constant clamp load over that range of motion. You do not need to retorque after heat-up and cool-down cycles.

Actual vs. Theoretical Curve: The 75% Rule

One important limitation: the actual load-deflection curve tracks the theoretical curve closely up to approximately 75% deflection. Beyond that point, the curves diverge as disc-to-disc or disc-to-support-plate contact shortens the effective lever arm. Do not size a working point above 75% deflection and expect theoretical performance to hold.

Worked Example: Flat Washer vs. Disc Spring

•   A flat washer under an M24 bolt loses almost all extra preload once the joint relaxes 0.1 mm.
•   A DIN 2093 disc spring with OD around 63 mm and h0/t tuned near 1.4 holds preload within about ±10 percent over the same 0.1 mm relaxation.
•   A valve packing follower might use a stack of 316 stainless steel disc springs sized around 40 mm OD. The stack is arranged in parallel pairs to maintain about 1,200 lb (around 5.3 kN) seat load at 400°F. These springs take up packing wear in the range of 0.5 to 1.0 mm without manual adjustment.

Always review supplier load-deflection curves. Confirm that your working point sits in the intended portion of the curve, not near full flattening.

Series vs. Parallel Stacking of Disc Springs

You rarely use a single washer in heavy industrial joints. Stacking lets you shape both total travel and total load.

Series Stacking

All springs   facing alternating direction. Total deflection equals the number of discs times the deflection of one disc at a given load. Load at a given deflection stays roughly equal to a single disc, apart from friction effects. 4 discs in series provide about 4 times the deflection of one disc at the same deflection point. This suits suspension, couplings, or mechanisms with high travel and constant force needs.

Parallel Stacking

  Springs nested together facing same direction . Load adds with the number of discs while deflection matches one disc. 4 discs in parallel deliver about 4 times the load of a single disc at roughly the same deflection. Used for high clamp force and low travel, such as pressure vessel flanges where custom and stock Belleville disc springs for diverse industrial applications are commonly specified.

Combined Stacks

Engineers build stacks like 2×2 (two in parallel, then two such groups in series) to achieve both higher load and higher travel. A 2s2p stack of a 100 kN disc gives about 200 kN load with double the deflection of one disc.

Friction, Fatigue, and Practical Stack Limits

Friction between discs introduces hysteresis and energy loss in parallel stacks. Many designers limit a single parallel group to about 4 discs and control lubrication and surface finish to keep performance repeatable.

For dynamic applications with high cycle counts, limit deflection to 75 to 80% of maximum. Operating consistently above this range accelerates fatigue. Static applications — valve seats, bearing preload, bolting — can use the full deflection range.

Typical Stack Configurations by Application

•   Series-dominant stacks: heavy equipment suspension points, clutches that need more travel.
•   Parallel-dominant stacks: flange live loading, relief valves, electrical contact pressure maintenance.

Material Selection for Disc Springs by Environment

Material choice drives load capacity, fatigue life, and survival in high-temperature or corrosive service.

Carbon Steel (AISI 1074/1075 or 6150)

Use for standard industrial applications with moderate cycles and clean environments. Typical continuous temperature up to around 250°F (120°C) with standard oils or phosphate coatings. Common in general machinery, plant utilities, and low-corrosion flange joints.

Alloy Steel (51 CrV 4)

Higher strength and better fatigue behavior for high-cycle disc springs. Suitable for temperatures up to roughly 390 to 480°F (200 to 250°C) depending on heat treatment. Used in clutches, presses, and actuators with many millions of cycles.

17-4 PH Stainless Steel (H900 Condition)

Combines corrosion resistance with high strength for aggressive environments. Handles wet or mildly corrosive service, with working temperatures roughly from −100°F up to 600 to 700°F. Good for valve live-loading kits, downhole tools with brine exposure, and offshore equipment.

17-7 Stainless Steel

Available for applications requiring a different balance of strength and corrosion resistance in the stainless family.

Inconel 718

Nickel-based alloy for sustained service above 900°F (480°C). Used in aerospace engine areas, turbine housings, and refinery equipment where both high temperature and corrosion are present; designers often reference Belleville International’s downloads and technical resources for high-temperature and cryogenic springs during selection. Supports high-cycle loading where carbon or standard stainless steels lose strength.

Exotic Alloys: Inconel X-750, Waspaloy, Titanium

Inconel X-750, Waspaloy, Titanium, and other exotic alloys are available for applications with requirements outside the standard material grades. Specify both operating temperature and media (oxygen, H2S, seawater, steam) when requesting a quote.

Material Selection Checklist

•   Maximum and minimum service temperature.
•   Expected cycle count per year.
•   Fluid chemistry and corrosion risk.
•   Regulatory needs (NACE, FDA contact, aerospace specs).

Industrial Applications for Belleville Disc Springs

Disc springs solve similar problems across many fields: maintain load in limited space under variable conditions.

Oil and Gas

•   Wellhead and Christmas tree flanges: disc spring stacks under nuts keep clamp load stable during pressure and temperature swings.
•   Blowout preventer stacks: disc springs maintain actuator preload and response times.
•   Downhole tools in shock tools, drilling jars, mud motors, centralizers, and hammer drills rely on Inconel 718 or 17-4 PH disc springs to maintain grip under vibration and high temperature at depths of several thousand meters, supported by Belleville springs and components for downhole drilling.

Aerospace and Defense

•   Actuator preload: disc springs keep ball screws or gear trains backlash-free under varying temperature and load.
•   Landing gear shimmy dampers: disc springs provide compact, high-load return forces in tight envelopes.
•   Hardware built to MIL-SPEC where weight and reliability are tightly controlled.

Heavy Equipment

•   Clutch packs: disc springs set engagement force and wear compensation.
•   Hydraulic valve spool retention: disc springs maintain centering forces where coils would be too tall.
•   Track tensioners: series stacks yield large deflection travel in limited axial space.
•   Torque limiters: disc springs apply force to friction pads, slipping under overload and re-engaging when load returns to normal.

Steel Mill and Electrical

•   Rolling mills use Belleville stacks in tracks to maintain consistent rolled steel thickness, often drawing on Belleville washers and disc springs engineered for steel mill equipment.
•   Electrode arms in electric arc furnaces use disc spring stacks for clamping force.
•   Coke oven door latches use large disc spring stacks to maintain seal and oven temperature.
•   Bolted electrical connections on bus bars use Belleville washers to compensate for thermal expansion and prevent hot spots that lead to joint failure.

Machinery and CNC

•   CNC machine spindle drawbars use disc springs to supply clamp force on the toolholder, similar in concept to industrial and heavy equipment disc spring solutions. Hydraulic force overcomes the springs to release the toolholder.
•   Regulators and actuators in aircraft, aerospace, and transportation equipment use disc springs for precise constant force.

Power Generation

•   Steam valve live-loading kits use disc springs to maintain packing stress in high-pressure valves around 900 to 1,000°F.
•   Turbine casing bolting: disc springs compensate for differential thermal growth during start-up and shutdown.
•   Heat exchanger tube-sheet bolting uses Belleville flange washers to maintain gasket sealing stress through temperature cycles.

Where do you fight repeated retorque or preload loss today? Review those joints for possible disc spring retrofits.

How to Specify a Disc Spring or Disc Spring Stack

Clear input data speeds selection and shortens quote time.

Five Key Parameters to Define

•   Outside diameter (OD) and inside diameter (ID): set the hardware envelope and fit over bolt or shaft.
•   Free height and target working height: the difference gives required deflection.
•   Required load at that deflection: state a numeric target, such as “20 kN at 0.6 mm deflection,” plus acceptable tolerance band.
•   Operating temperature range: minimum and maximum continuous and any short-term excursions.
•   Environment and media: presence of water, chlorides, sour gas, or food product that drives material and finish choices.

Using DIN 2093 as a Starting Point

DIN 2093 covers standard dimensions, materials, and performance for many metric disc springs manufactured to ISO quality standards. You can pick a DIN size as a starting point and adjust stacking to reach your final load and travel.

Custom Parts and Lead Times

Belleville International produces outside-standard diameters, thicknesses, and surface treatments when catalog discs do not fit, and also provides custom-machined Belleville springs and precision valve components for specialized valve applications. The manufacturing range runs from 0.500″ to over 42″ O.D. Lead times can be as short as 2 to 5 business days for carbon steel sizes and longer for exotic alloys depending on material availability; you can request a detailed quote and custom design support using the online form. Same-day quotes, designs, and shipments are available. There is no minimum order quantity.

Send application drawings or bolt layout sketches with your quote request so engineers can check contact stresses, stack height, and assembly method, or contact the sales and engineering team directly for assistance.

Request a Quote for Disc Springs

Request a quote for Belleville disc springs or Belleville disc spring stacks tailored to your flange, valve, actuator, or custom assembly. Application engineers will review your required load, travel, temperature, and environment, then confirm disc spring size, DIN series, stacking configuration (series, parallel, or combined), and material and surface finish suitable for the service conditions.

Contact our Belleville disc spring sales and engineering team to get started, or review Belleville International’s background and capabilities to understand their design and manufacturing expertise. Attach any relevant drawings, bolting data, and operating conditions in the form to speed your selection.

FAQ: Belleville Disc Springs

How do I know if a disc spring will fit under my existing bolt head or nut?

Measure available washer face diameter, recesses, and projected nut rotation clearance. Pick a disc spring OD that fits within that space with margin. The ID must clear the bolt shank with enough tolerance to avoid binding under misalignment or thermal growth. Send bolt size, flange standard (such as ASME B16.5 class), and any counterbore dimensions with your quote request for engineers to confirm fit.

Can disc springs replace coil springs in my design?

Disc springs work well when you need very high load in a short axial height, such as preloading bearings, flanges, or clutches. Coil springs suit applications that need longer travel with lower specific load and smoother rate. Compare available axial space, required load, and stroke. Choose the element that meets those numbers most efficiently.

How long do disc springs last in cyclic applications?

Fatigue life depends on material, stress range, surface finish, and lubrication. In dynamic applications, limit deflection to 75 to 80% of maximum to extend fatigue life. Properly selected disc springs can reach millions of cycles in controlled service. Alloy steels such as 51 CrV 4 usually give longer fatigue life than basic carbon steel when stressed to similar levels. Keep working stress below published fatigue limits and avoid operation very close to full flattening.

Do I need lubrication between disc springs in a stack?

A light film of suitable lubricant between discs often reduces friction, improves repeatability, and lowers hysteresis in high-cycle or static stacks. Some applications in clean or food environments may use dry-film coatings that meet regulatory rules. Discuss lubrication and coating needs with the supplier so friction behavior matches expected load-deflection performance.

What standards apply to disc springs besides DIN 2093?

European standards such as DIN EN 2093 (quality and dimensions) and DIN EN 2093(calculation) relate to disc springs and may appear on data sheets. Belleville International operates under ISO 9001:2015 certification, with full material traceability from raw material heats through heat treatment cycles and testing certifications and supplies Belleville washers and springs for oil and gas drilling and refining applications. Reference the specific standard in your purchase documents if you must align with plant or industry requirements.