Testing of helical spring under compression test

Vehicle springs are made of (ultra) high-tensile and heat-treated steel,
subjected to high static and cyclical loads and sensitive to superficial defects that can be caused
by mechanical and corrosive action during production or operation. To reduce the risk of
fracture, manufacturers use different types of surface coatings that provide protection against
both corrosion and mechanical damage by grit or other abrasives. This document examines the
complex stress conditions for vehicle springs and describes the most frequent types of damage. It
presents the findings of an extensive test project that was conducted primarily to examine the
influence of corrosion combined with mechanically generated surface defects on the durability of
vehicle springs. Comprehensive durability tests on generic springs manufactured with different
technologies are verified and quantification of the dominant influence of advance mechanical
damage by grit impact and abrasion on the fatigue strength under loading conditions can be done.
An effective countermeasure is to improve surface protection.