High Temperature Materials

A number of precipitation-hardenable materials from the group of nickel-base alloys are used for disc springs operating at elevated temperatures. They are highly ductile and have very high fatigue strength. When designing springs made of thermally stable materials, their lower tensile strength and unfavourable elastic limit - tensile strength ratio must be taken into account. Otherwise, a high degree of setting loss is possible.

It is not possible to specify an upper operating temperature limit. The overall height of the spring decreases under load due to creep. The actual level of creep is a function of temperature, time and stress. For example, a spring canbe used at higher temperatures if eithera lower load is applied or the duration at the elevated temperature is short. Therefore, the values in Table 5.1 can serve only as guide for the maximum temperatures at which the disc springs will exhibit the same behaviour as at room temperature.

It must be kept in mind that the modulus of elasticity is somewhat lower in the upper temperature range of the material than at room temperature. Taking this into account, disc springs made of thermally stable materials can be used at temperatures up to approx. 150° C higher than those stated in Table 5.1.

The delivery times for thermally stable materials are typically very long. If material is in stock, the delivery times for production orders are the same as for normal steel springs. Nimonic 90 is better suited for extremely high temperatures than Inconel X 750 (or Inconel 718).

It should be noted that thermally stable materials are typically very expensive.

The properties of the materials used by Mubea are listed in the following tables, and can be downloaded here: