The spring constant describes at Compression springs , Tension springs and Torsion springs the increase in force in relation to the Suspension travel , or with torsion springs in relation to the angle of rotation. It is also called Spring
The spring blog
What does the Relaxation with metal springs? This has little to do with a recovery phase of the spring, but describes the unintentional increasing loss of force of the spring with increasing ambient temperature and duration of load. Or what