For best service from INCONEL alloy X-750 springs, a temper and heat treatment must be selected that will develop the properties required for the application under consideration. Wire and strip used for helical and flat springs are usually produced in two tempers: No. 1 Temper, which represents material that has been cold-reduced about 15 to 20% after the final process anneal; and Spring Temper, which represents material that has been cold-reduced approximately 30 to 65% after the final process anneal. Some springs are also made from hot-finished material.

Design stresses for helical and flat springs are shown below. This table may be used as a guide for selection of the appropriate temper and heat treatment for the intended service temperature. As temperatures decrease below room temperature, strength and modulus will increase; therefore, if specific test data at cryogenic temperatures are not available, springs for service at these temperatures may be safely designed based on room-temperature properties.