FAQs and Reliable Grok Quick answers on disc springs and load washers

We’ll suggest a close match, but if an exact match is needed, that is not a problem. We are well known for our bespoke and non-standard disc spring solutions. We have our own toolmaking team and heat treatment capability, so die making is very quick. You can also search all our standard sizes.

For the DIN 6796 heavy load washer range we generally have stock up to a bolt size of M33. Everything else, up to M125, is manufactured when you order. Manufacture takes 5 to 7 days if we are not busy.

For DIN EN 16983 disc springs, if you are a repeat customer, we manufacture and reserve your standing order so that you can collect it immediately.

Because we manufacture well over 500 different disc springs across the three groups, it is not practical to keep stock of every size. However, the popular Group 2 sizes (1.25 to 6.0 mm material thickness) are always kept in stock.

Strictly speaking, two standards are involved:

• DIN EN 16983 – quality requirements and dimensions, which replaces DIN 2093;
• DIN EN 16984 – calculation, which replaces DIN 2092.

DIN 2092 and DIN 2093 were German standards and have now been incorporated into European standards. The content has not changed in any substantive technical way.

We manufacture ourselves, and we are one of the few manufacturers worldwide that will provide you with:

• a confirmation load characteristic curve for the individual disc spring or for the stack you are making up;
• a material certificate for the metal used to manufacture your disc springs;
• a heat treatment certificate with the Rockwell C hardness attained and, very importantly, assurance on the tempering cycle;
• on request, an independent load cycle test confirming the predicted load characteristic curve, done by the CSIR or SGS Metlab (see testing);
• on request, our ISO 9001:2015 QMS records. For any batch of disc springs we invoice, we can trace who signed off the tooling, who checked the material, the operator and machinist who worked on your disc springs, who conducted the heat treatment hardness tests, and so on.

We use a range of materials, depending on key variables of the operating environment, such as:

• ambient operating temperature;
• magnetic flux density;
• chemical corrosiveness, through the presence of acids, bases and oxidisers;
• industry standards, especially in aviation and food.

The vast majority of applications only need either a high-carbon steel (SAE 10xx) or a chromium-vanadium alloy steel (51CrV4). In dense flux environments we must prevent induction heating and use a non-magnetic metal. High flux usually comes with a high ambient temperature, and there INCONEL is our preference. Beryllium copper, on the other hand, is great for sub-zero temperatures where electrical components predominate. For corrosive environments where contamination must be avoided (as in food processing), we have FDA-approved high-density polymer disc springs. See our materials page for more.

All our chromium-vanadium alloys (SAE 6150 / 51CrV4), non-magnetic high-temperature alloys (INCONEL X-750) and high-carbon spring steels (65Mn / SAE 1065) are imported in annealed 2500 × 1250 mm plate or sheet form, in thicknesses from 0.5 mm to 20 mm.

Disc springs follow the DIN EN 16983 standard, while load washers follow DIN 6796. They are designed to fulfil different functions in different applications.

Load washers follow the standard bolt sizes, and there are far fewer of them: we have 30 sizes from M2 to M125. A DIN 6796 heavy load washer is used on its own to secure a static bolted connection. The high torque applied, and the resulting force, keeps a permanent pressure on the joint between a hardened bolt and its nut, to prevent loss of preload and the joint loosening.

Disc springs are designed to meet specific (and generally dynamic) loading or energy-absorbing functions, so there are at least 500 different standard and common disc spring sizes. They are used as springs, either individually or in stacks, and generally carry a dynamic load rather than a single static load. The last big difference is that disc springs have much stricter tolerances, because they have more specific performance requirements in mission-critical applications.

Smaller DIN 6796 load washers are made in the same way as Group 1 and 2 disc springs, except for the key radii, final polishing and surface treatment steps. Larger DIN 6796 washers and Group 3 disc springs are also made from chromium-vanadium spring steel, first laser cut into blanks that are then CNC machined. The Group 3 disc springs have contact flats (working surfaces) machined, while the load washers do not. The same stringent quenching and tempering protocols must be followed for both.

For disc springs thicker than 6.0 mm (Group 3), DIN EN 16983 specifies small contact surfaces. A contact flat shortens the moment arm. Think of a lever: as it gets shorter, more force is needed to move the same load. So, all else being equal, adding contact flats means the disc spring needs a greater load for the same deflection.

For very practical reasons of interchangeability, which means keeping the free height of the spring and matching the loads as closely as possible, the thickness of the disc spring must be reduced (t′). DIN EN 16984 requires a reduced-thickness disc spring to give the same load at s = 0.75 h₀ as the equivalent disc spring without contact flats. Read more on our Group 3 design page.

We call the contact flat an annulus. DIN EN 16983 refers to it as a ground surface end, and the SAE HS-1582 Spring Design Manual as a contact bearing flat. Contact flats have a purpose:

• to improve the definition of the point where the load is applied;
• in stack configurations, to reduce the friction on the stack guide.

They substantially improve performance and prolong operational life.