Thermally Stable Materials

For thermally stable belleville disc springs, martempered steels are generally thermally stable disc spring materials due to their high alloy content. In contrast to standard disc spring materials, martempered steels display a lower level of creep at the higher temperature ranges. The thermally stable disc spring material was exposed to high temperatures for a long length of time in order to obtain the higher operating temperatures detailed in (Table 5.1). In addition, the disc springs may be exposed, for brief moments (roughly about 1 hour), to temperatures approximately 100 °C higher than those listed without disturbing their properties. The modulus of elasticity is very critical during disc spring design, since it decreases as the temperature ascends and increases as the temperature descends. Hence, disc springs will exhibit a lower force at greater than room temperatures and a higher force at lesser than room temperatures. Brittle fracture is probable during untimely failures for disc springs manufactured with thermally stable materials.

X 35 CrMo 17 (DIN 1.4122)

X 35 CrMo 17 has a high thermal permanence due to the addition of molybdenum (Mo). In some applications, this thermally stable material is corrosion resistant, but limited at the material strengths required for disc springs. The material is not corrosion resistant when introduced to seawater or similar environment.

X 22 CrMoV12 1 (DIN 1.4923)

This material is a heat-treatable molybdenum and vanadium steel containing thermally stable chrome for applications with operating temperatures of – 60° C to 350° C. X 22 CrMoV 12 1 may hastily be unsuccessful due to brittle-fracture.