In general, Solon Belleville Springs are designed to be loaded to flat without damaging them. However, this does not mean they should be bolted to flat in every case. There are some applications where a spring should be employed at a load considerably lower than the flat load. For instance, when elevated temperatures may damage the springs, it may be necessary to use a heavier spring in order to keep the stresses below a certain threshold. Additionally, in some elevated temperature applications it may be desirable to allow the spring to partially "absorb" the differential expansion to prevent excessive loading.