3.2.1 All impact tests are to be carried out on Charpy machines accepted by Clasifications
Register (hereinafter referred to as LR) in accordance with the requirements of Ch 2, 1.2 Testing machines 1.2.1 and having a striking energy of
not less than 150 J.
Table 2.3.1 Dimensions and tolerances for
Charpy V-notch impact test specimens
| Dimension
|
Nominal
|
Tolerance
|
| Length, in mm
|
|
55
|
±0,60
|
| Height, in mm, see
Note 1
|
|
10
|
±0,075
|
| Width , in mm, see
Note 1
|
|
|
|
|
|
- standard specimen
|
10
|
±0,11
|
|
|
- standard subsidiary specimen
|
7,5
|
±0,11
|
|
|
- standard subsidiary
specimen
|
5
|
±0,06
|
| Angle of
notch
|
45°
|
±2°
|
| Height
below notch, in mm
|
8
|
±0,075
|
| Root
radius, mm
|
0,25
|
±0,025
|
| Distance of plane of symmetry of notch from ends of test piece,
in mm, see Note 1
|
|
|
| 27,5
|
±0,42
see Note 2
|
| Angle
between plane of symmetry of notch and longitudinal axis of test
piece
|
90°
|
±2°
|
| Angle
between adjacent longitudinal faces of test piece
|
90°
|
±2°
|
|
Note
1 The test piece is to have a surface
roughness better than Ra 5 μm except for the ends.
Note
2 For machines with automatic positioning
of the test piece the tolerance is to be taken as ±0,165 mm.
|
3.2.2 Charpy V-notch impact tests may be carried out at ambient or lower
temperatures in accordance with the specific requirements given in subsequent Chapters
of these Rules. Where the test temperature is other than ambient, the temperature of the
test specimen is to be controlled to within ±2°C for sufficient time to ensure
uniformity throughout the cross-section of the test specimen, and suitable precautions
are to be taken to prevent any significant change in temperature during the actual test.
In cases of dispute, ambient temperature is to be considered as 23°C±5°C consistent with
ISO 148-1.
3.2.3 For acceptance,
the average energy value for a set of three impact tests must be equal
to or greater than the appropriate specified minimum average value.
Additionally, only one individual value may be less than the required
average value but not less than 70 per cent of this average value.
3.2.4 Where standard
subsidiary Charpy V-notch test specimens are necessary, the minimum
energy values required are to be reduced as follows:
- Specimen 10 x 7,5 mm: 5/6 of tabulated energy.
- Specimen 10 x 5 mm: 2/3 of tabulated energy.
3.2.5 When reporting
results, the specimen dimensions and the units used for expressing
the energy absorbed (Joules) and the testing temperature are to be
clearly stated.