|
|
发表于 2008-3-26 11:44
|
显示全部楼层
来自： 中国山东烟台
B 300 Impact testing
301 Impact testing is to be carried out as Charpy V-notch test
according to the specification in question. Each value for absorbed
energy is to be determined as the average of one set of
3 impact test pieces.
302 The Charpy V-notch impact toughness is the absorbed
energy, expressed in Joule (J), the symbol being KV.
303 The Charpy impact test machine is to be of a type acceptable
to the Society having a gap of 40 mm, a striking velocity
between 4.5 and 7 m/sec. and a striking energy of 290
±10 J for a standard test. The angle between the striking edges
of the pendulum is to be 30° with the edge rounded to a radius
2 to 2.5 mm. (Pendulum according to ASTM E 23 will also be
accepted.)
The point of impact of the hammer is to be in the centre line of
the notch. The scale of the machine is to be calibrated to an accuracy
of +0.5% of the machine's maximum striking energy.
Impact test machines with a striking energy of less than 290 J
are acceptable. In such cases, KV is to be supplemented with
an index giving the striking energy.
For example, KV145 indicates that a striking energy of 145 J
has been used.
304 Dimensions and tolerances for Charpy V-notch test
pieces are to comply with the specifications given in 305.
The test samples may be flame-cut but the notch is not to be
nearer to a flame-cut edge than 25 mm. The prescribed dimensions
are to be accurately and systematically checked.
The notch is to be made in a single cut by a special milling cutter.
The cutter is always to be kept sharp so that the shape of
the notch is correct and cold working at the base is avoided as
far as possible. The cutter is not to be used for more than 100
test pieces between each checking.
There are to be no indications, scratches or marks left in the
base of the notch after machining. The plane of symmetry of
the notch is to be at right angle to the longitudinal axis of the
test piece.
305 Dimensions and tolerances for Charpy V-notch test
pieces are to be as in Table B1.
306 Standard Charpy V-notch test pieces with width 10 mm
are to be used, except when the thickness of the material does
not permit this size. In such cases the largest obtainable of the
subsize test pieces with width 7.5 mm or 5 mm is to be used.
For tubes and pipes also a subsize test piece with width 2.5 mm
is to be used if necessitated by the dimensions.
307 The temperature of the test piece at the moment of
breaking is to be the specified temperature within ±2°C.
Test temperature is to be stated in the certificate.
Guidance note:
The required temperature tolerance is usually obtainable by immersing
the test piece for at least 2 minutes in an agitated liquid
bath having the specified test temperature, and have the test piece
broken within 5 seconds after withdrawal from the bath.
---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---
Fig. 4
Charpy V-notch test piece.
B 400 Drop-weight testing
401 For material with thickness t equal to or greater than 16
mm, drop-weight test pieces for the determination of nil ductility
transition temperature are to comply with specifications
given in ASTM E208, and have one of the following sizes:
No. 1: 25 by 90 by 360 mm
No. 2: 19 by 50 by 130 mm
No. 3: 16 by 50 by 130 mm.
For material thicknesses below 16 mm down to and including
12 mm, a test piece machined down to 12 mm thickness is to
be used. For material thicknesses below 12 mm down to and
including 10 mm, the thickness of the test piece is to be that of
the material. Other dimensions and requirements for test piece
with thickness below 16 mm are to be as for test piece no. 3
above, except that a stop distance of 2.3 mm is to be used.
402 The test pieces may be cut with their axes either transverse
or longitudinal to the final rolling direction of the material,
but the orientation is to be the same for all test pieces.
403 The sides of the test pieces are to be saw-cut or machined.
The distance from a flame-cut surface is to be min. 25
mm.
The machining of the test piece to prescribed thickness is to be
on the compression side only.
404 Two test pieces are to be tested at the prescribed test
temperature. Both test pieces are to exhibit a non-break performance,
i.e. the nil ductility transition temperature is to be
below the test temperature.
405 The drop-weight test is to be carried out and evaluated
according to ASTM E208.
B 500 Determination of grain size
501 Where the austenitic grain size is specified, it is to be determined
according to methods described in recognized standards.
At least one sample is to be taken from finished material
from each ladle. For rolled products the sample is preferably to
be taken from the thickest piece rolled. The grain size numbers
refer to the ASTM scale described in ASTM E112.
B 600 Other testing
601 Testing not described in item 100—600 may be required
for certain products. In such cases testing is to be carried out in
accordance with procedures approved by the Society.
Table B1 Charpy V-notch test pieces.
Dimensions Nominal Tolerances
Length 55 mm 0,60 mm
Width
- standard test piece
- subsize test piece
- subsize test piece
- subsize test piece
10 mm
7.5 mm
5 mm
2.5 mm
±0.11 mm
±0.11 mm
±0.06 mm
±0.06 mm
Thickness 10 mm ±0.06 mm
Angle of notch 45° ±2°
Depth below notch 8 mm ±0.05 mm
Root radius 0.25mm ±0.025mm
Distance of notch from ends
of test piece 27.5 mm ±0.42 mm
Angle between plane of symmetry
of notch and longitudinal
axis of test piece 90° ±2°
width
thickness |
|
提升卡
变色卡
发表于 2008-3-25 16:11
楼主