Proceq Equotip 3, Руководство по эксплуатации

Страница: 5 / 36

© 2012 by Proceq SA
5
2. Tutorial on Leeb rebound hardness testing
2.1. Test principle
During measurement with Equotip 3 impact devices (D, DL, DC, C, G, S, E), an impact body
with a ball indenter is launched by spring energy against the sample to be measured, and then
rebounds. Before and after the impact, a permanent magnet inside the impact body passes
through a coil in which a voltage signal V is induced by the forwards and backwards move-
ment. This induction signal behaves proportionally to the velocities. The ratio of the rebound
velocity v
r
to the impact velocity v
i
multiplied by 1000 yields the hardness value HL (Leeb hard-
ness). HL is a direct measure of the hardness.
2.2. Sample preparations
Keep the sample free of vibrations during the test. Light and thin parts must be specially fas-
tened (see section 2.6. “Testing light samples”). Ensure that the surface of the work piece is
clean, smooth and dry. If required, use appropriate cleaning agents for cleaning, such as ac-
etone or isopropanol (no water!).
2.3. Test conditions
Impact device type
Minimum sample weight
Sample of
compact shape
Sample resting
on solid base
Coupled to
solid base
C 1.5 kg (3.3 lbs) 0.5 kg (1.1 lbs)
0.02 kg (0.045 lbs)
D, DC, DL, S, E 5 kg (11 lbs) 2 kg (4.5 lbs)
0.1 kg (0.25 lbs)
G 15 kg (33 lbs) 5 kg (11 lbs)
0.5 kg (1.1 lbs)
Impact device type
Minimum sample thickness
Uncoupled Coupled
Top layer
thickness
C 10 mm (2/5 in) 1 mm (1/25 in)
0.2 mm (8 µin)
D, DC, DL, S, E 25 mm (1 in) 3 mm (1/8 in)
0.8 mm (32 µin)
G 70 mm (2 in) 10 mm (2/5 in)
N/A
Impact device type
Sample surface condition
Roughness class
ISO
Maximum roughness
depth Rt
Average rough-
ness depth Ra
C N5 2.5 µm (100 µin)
0.4 µm (16 µin)
D, DC, DL, S, E N7 10.0 µm (400 µin)
2 µm (80 µin)
G N9 30.0 µm (1’200 µin)
7.0 µm (275 µin)
Impact device type
Maximum sample hardness
in HL in HRC
in HV in HB
G 750 HLG N/A
~ 675 HV ~ 645 HB
D, DC 890 HLD ~ 68 HRC
~ 955 HV N/A
DL 950 HLDL ~ 68 HRC
~ 955 HV N/A
C 960 HLC ~ 70 HRC
~ 1010 HV N/A
S 890 HLS ~ 70 HRC
~ 965 HV N/A
E 855 HLE ~ 72 HRC
~ 1200 HV N/A
Impact device type
Minimum space
Between indentations
Between indentation and sample edge
C 2 mm (1/12 in)
4 mm (1/6 in)
D, DC, DL, S, E 3 mm (1/8 in)
5 mm (1/5 in)
G 4 mm (1/6 in)
8 mm (1/3 in)