Spring Material Hardness

To obtain accurate readings, free from the effect of the anvil, it is important to limit the thickness of the spring wire material for each hardness scale as shown in Figure 1 for hard materials and Figure 2 for soft materials.

Thickness: mm (in.)

0.89 (0.035) and over
0.64 - 0.86 (0.025 - 0.034)
0.35 - 0.61 (0.015 - 0.024)
0.20 - 0.36 (0.008 - 0.014)
Under 0.20 (0.008)

Tempered Steel

C
A
30 N
15 N
DPH

Annealed Steel and Nonferrous Alloys

B
45 T
30 T
15 T
DPH

Properties of Common Spring Materials

The properties of common spring materials chart lists some commonly used alloys along with data for material selection purposes. These specifications were developed exclusively for high quality material for spring applications and are generally more detailed and stringent than other specifications.

Surface quality has a major influence on fatigue strength and is often not clearly delineated on national specifications. It is important to use only those materials with the best surface integrity for fatigue applications, particularly those in the high cycle region.

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