Spring Material Hardness
Overview
Spring hardness tests are used extensively to inspect strip and flat springs, and it is necessary to specify the correct scale. Recommended hardness scales for steels are presented in the table below.
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.) |
Tempered Steel |
Annealed Steel and Nonferrous Alloys |
0.89 (0.035) and over |
C |
B |
0.64 - 0.86 (0.025 - 0.034) |
A |
45 T |
0.35 - 0.61 (0.015 - 0.024) |
30 N |
30 T |
0.20 - 0.36 (0.008 - 0.014) |
15 N |
15 T |
Under 0.20 (0.008) |
DPH |
DPH |
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