Some standard content:
ICS 77. 040. 10
National Standard of the People's Republic of China
GB/T3808--2002
Replaces GB3/T3808-1995
Verification of pendulum-type impact testing machines(ISO 148-2: 1998,Metallic materials---Charpy pendulum impact testPart 2:Verification of test machines,MOD)2002-02-22Promulgated
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
2002-08-01Implementation
GB/T 3808--2002
The series of standards for Charpy pendulum impact test consists of the following three national standards: GB/T229 "Metal Charpy notch impact test method": GB/T3808 "Testing of pendulum impact testing machine"; -GB/T18658 "Charpy V-notch standard specimen for testing pendulum impact testing machine". This standard is one of the series of standards
This standard is modified to adopt the international standard ISO148-2:1998 "Metallic materials Charpy pendulum impact test Part 2: Testing machine testing" (English version).
This standard was drafted based on ISO148-2:1998 using the translation method. It is consistent with ISO148-2:1998 in terms of text structure and technical content. However, according to the relevant provisions of my country for the compilation of standards, the following editorial modifications have been made: - To unify with the existing series of standards, the standard name has been changed and it has been published as a national standard with an independent number; - ·: "this standard" replaces "this part of IS0148"; - The decimal point symbol "" used in Chinese replaces the decimal point symbol used in English; - The decimal point symbol in ISO148-2:19 has been deleted. 98; modified the introduction in Chapter 2 "Normative References" and directly quoted the Chinese national standards corresponding to the international standards cited in IS0148-2:1998. The cited GB/T229-1994 is a national standard that is not equivalent to ISO148:1983 and needs to be revised according to the new international standard ISO148-1:1998. For this reason, the consistency degree of this standard with the international standard is "modified";
changed the format of the terminology and modified it according to the Chinese expression habits Related tables and formulas; corrected printing errors (see footnote of 3.1.4). This standard replaces GB/T3808-19.95 "Pendulum Impact Tester". This standard mainly makes the following revisions to GB/T3808--1995: a) The overall structure of the standard is adjusted according to ISO148-2:1998; b) Added potassium subsections and foreword;
c) Added the provisions of U-shaped hammer and expanded the scope; d) Redefined terms and symbols;
Deleted "Structure, parameters", "Inspection rules", "Marking, packaging" , transportation, storage, completeness and random documents" and other technical elements; e)
f) Some technical indicators and test methods are consistent with ISO148-2:1998--. This standard is proposed by the China Machinery Industry Federation. This standard is under the jurisdiction of the National Technical Committee for Standardization of Testing Machines. The responsible drafting unit of this standard: Changchun Testing Machine Research Institute. The participating drafting units of this standard: Wuzhong Materials Testing Machine Co., Ltd. and Jinan Shijin Group Co., Ltd. The main drafters of this standard: Guo Yongxiang, Xu Ren, Tao Liying. The previous versions of the standards replaced by this standard are: GB/T 3808--1983, GB/T 3808-1995.4.16
1 Scope
Testing of pendulum impact testing machines
GB/T3808—2002
This standard specifies the testing methods for pendulum impact testing machines. This standard applies to pendulum impact testing machines (hereinafter referred to as testing machines) equipped with 2mm or 8mm impact knives and used for pendulum impact tests in accordance with test methods such as those specified in GB/T229. Other testing machines with different capacities and structures can also refer to this standard. Testing machines used in industry, ordinary laboratories or research laboratories for metal material testing and that comply with the provisions of this standard are called working testing machines. Testing machines with more stringent requirements are called standard impact testing machines, and the inspection of standard impact testing machines is specified in GB/T18658.
This standard describes two testing methods.
a) Direct method. This method is actually a static inspection method, that is, by measuring the key components of the testing machine to ensure that it meets the requirements of this standard. The inspection instrument used should be proven to be traceable to the national benchmark of my country's legal measurement units. When the testing machine is installed or repaired or the indirect method gives incorrect results, it should be inspected using the direct method; b) Indirect method. This method is actually a dynamic inspection method, that is, using a standard specimen to inspect the indication on the indicating device. This standard requires the use of both direct and indirect methods to inspect the testing machine (see Chapter 12). The technical requirements for standard specimens are specified in GB/T18658. Note: The indirect method specified in this standard only considers the total energy absorbed by the specimen fracture. The total energy includes: 1) The energy required to break the specimen itself: 2) The internal energy loss of the pendulum of the testing machine from the initial position to complete the first half cycle. The internal energy loss is due to: a) air resistance, friction of the pendulum shaft bearing and friction of the pointer. These energy losses can be measured by direct methods (see 9.4); b) impact of the foundation, vibration of the frame and pendulum. There is no appropriate measurement method and measuring instrument for measuring these energy losses. 2 Normative references
The clauses in the following documents become the clauses of this standard through reference in this standard. For dated references, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties to an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For undated references, the latest versions apply to this standard. GB/T229Metallic Charpy notched impact test method (ISO148:1983Steel—Charpy impact test (V-notch), NEQ)
GB/T18658Charpy V-notch standard specimen for pendulum impact test machine inspection (ISO148-3:1998Metallic ferrials-Charpy pendulum impact testPart 3: Preparation and characterization of Charpy V reference test pieces far verification of test machines, MOD) 3 Terms and definitions
The following terms and definitions apply to this standard. 3.1 Terms and definitions of testing machines
Anvil
The part of the testing machine base that is processed into a vertical support surface to block the specimen from being struck by the pendulum (see Figures 1 to 3). This support surface is perpendicular to the support surface of the specimen support.
Base
The part of the testing machine frame that is below the horizontal support surface of the specimen support. 3.1.3
Center of percussionThe point on the pendulum where the effect of striking the specimen at this point is alternating with the effect of striking the specimen if the entire mass of the pendulum is concentrated at this point (see Figure 4). Note: When a simple pendulum strikes once along a horizontal line through the center of percussion, the pendulum axis does not produce a horizontal reaction force. 3.1.4
center of strike
Place a specimen or an equivalent gauge with a height of half the standard height (i.e. 5 mm) on the specimen support. When the pendulum is in the free hanging position, the point on the impact knife blade contacts the upper horizontal surface of the specimen or gauge (see Figure 3). 3.1.5
Working test machineindustrial machineIndustrial testing machine used by ordinary laboratories or most research laboratories for testing metal materials. These testing machines are not used to give standard values. The inspection of working testing machines shall be carried out in accordance with the methods specified in this standard. 3.1.6
Reference machine A test machine used to determine the standard energy of a reference specimen. The inspection requirements for this type of test machine are stricter than those for a working test machine and are specified in GB/T: 18658.
Strike
The part of the hammer body that contacts the specimen. The blade that actually contacts the specimen may have a radius of curvature of 2 mm (2 mm striker) or a radius of curvature of 8 mm (8 mm striker). (See Figure 2).
Test piece supports
The horizontal support surface machined on the base of the test machine is used to pre-place the part of the specimen struck by the pendulum (see Figures 2 and 3). The support surface is perpendicular to the support surface of the brick base.
3.2 Definition of energy
Actual absorbed energy (absorbed energy) The total energy required to break the specimen when the test machine is used to test. It is equal to the difference between the potential energy of the pendulum at the initial position and the potential energy of the specimen after the first half of the fracture has been completed (see Chapter 9). 3.2.2
Actual initial potential energy (potential energy) Apactual initial potential energy (potential energy) The value measured by direct inspection (see 9.1). 3.2.3
Asindicated absorbed energy (indicated energy) The energy value indicated by the pointer of the testing machine or other indicating device. 3.2.4
1) The original text of 1S0148-2 is \(see Figure 2)\, which is incorrect and corrected by this standard. 448
GB/T 3808—2002
Annominal initial potential energy (nominal energy) The energy value given by the manufacturer of the testing machine.
Standard energy Ar reference energy The absorbed energy value of the standard specimen, which is measured by the standard testing machine. 3.3
Reference test pieces are impact test pieces used to compare the indicated energy measured by the testing machine with the standard energy value marked on the test piece to check the suitability of the working testing machine. The reference test pieces are prepared in accordance with the requirements of GB/T18658. 3.4 Definition of relevant test pieces (test position placed on the support of the testing machine) (see Figures 2 and 3) 3.4.1
Height height
The distance between the face with the notch and the face opposite to it. 3.4.2
Width width
The dimension parallel to the notch and perpendicular to the height direction. 3.4.3
Length length
The maximum dimension perpendicular to the notch direction.
4 Symbols
This standard adopts the symbols and their meanings in Table 1. Table 1 Symbols and their meanings
Symbol (see Figure 4)
E or β
E, or β
E: or Bs
J or degree ())
J or degree (°)
J or degree (°)
Nominal value of initial potential energy (nominal energy)
Actual initial potential energy (potential energy)
Standard energy of a group of Charpy standard specimens
Indicated value of absorbed energy (indicated energy)
Actual absorbed energy (absorbed energy)
Indicated energy of the testing machine when there is no specimen on the support and it is operating normally Or when there is no specimen on the angle support, the indicating device is not reset and the machine is operating normally, the indicated energy of the testing machine or the angle of rise when there is no specimen on the angle support, the indicating device is not reset and the machine is operating normally, the indicated energy of the testing machine after the 11th half cycle of swing or the angle of rise
The force of the pendulum measured at a distance of 12The height of the pendulum falling
The height of the pendulum rising
The distance from the axis of the pendulum to the center of the specimen (impact point) (the length of the pendulum)The distance from the axis of the pendulum to the center of the impact
The distance from the axis of the pendulum to the point of action of the force F
Torque, etc. The product of ten F×12
GB/T 3808-2002
Symbol (see Figure 4)
Testing machine
Degree (\)
Degree (°)
Table 1 (continued)
Energy loss caused by pointer friction
Energy loss caused by pendulum shaft bearing friction and air resistance Correction amount of energy loss when the lift angle is 3
「Pendulum period
【Total time for the pendulum to swing 100 times||t t||【Maximum value of T
Minimum value of T
【Pendulum gravity
Angle of fall of pendulum
【Angle of rise of pendulum
The testing machine consists of the following parts (see Figures 1 to 3): a)
Foundation and (or) installation;
Structure supporting the pendulum, excluding foundation; pendulum with hammer body;
d) Anvil and support (see Figures 2 and 3);
6 Inspection
Indicator (e.g. dial and pointer or electronic display) of the absorbed energy. The inspection can only be carried out after the testing machine is installed. The inspection items are as follows: a)
Foundation and (or) installation;
Frame;
Pendulum, including hammer and impact knife;
d) Anvil and support;
e) Indicator.
Foundation and (or) installation
The foundation of the testing machine and the method of fixing the testing machine to the foundation are very important. 7.1 After the testing machine is installed, the foundation cannot usually be inspected again. Therefore, the technical documents at the time of installation must be provided to ensure that the mass of the foundation is not less than 40 times the mass of the pendulum.
7.2 The inspection of the testing machine installation shall include the following: Ensure that the bolts are tightened to the torque value specified by the manufacturer. The torque value shall be given in the technical documents provided by the manufacturer (see a)
7.1). If the user uses or chooses other methods for installation, it must be ensured that the effect of installation according to the above torque value is achieved; b) When performing the impact test, ensure that the test machine is not subjected to external vibration transmitted from the foundation. Note: For example, if a small container filled with water is placed in the appropriate position of the frame, if the surface of the water does not fluctuate, it indicates that this requirement is met. 8 Frame
The inspection of the frame (see Figure 1) should include the following items: 450
The free hanging position of the pendulum;
The position of the pendulum relative to the support;
The axial clearance and radial clearance of the pendulum bearing; c)
d) The distance between the hammer and the frame
Testing machines manufactured after the release of this standard should have a reference surface as a reference point for measurement. GB/T 3808—2002
8.1 The parallelism between the axis of the pendulum shaft and the reference surface should be within 2/1000. This item should be given by the manufacturer in the certificate of conformity. 8.2 When installing the testing machine, the reference surface should be level within 2/1000. For testing machines without a reference surface, the pendulum axis should be directly adjusted to within 4/1000, or a reference surface that can verify the levelness of the pendulum axis should be specified as above. 8.3 When the pendulum is freely suspended, the gap between the impact knife blade and the specimen should be within 0.5 mm. Note: A rectangular cross-section gauge with a length of about 55 mm, a height of 9.5 mm, and a width of about 10 mm (see Figure 3) can be used to measure the gap between the impact knife blade and the gauge. 8.4 The angle of the pendulum swing plane relative to the pendulum axis should be 90° ± 0.1° (3/1000). 8.5 The impact knife should be in full contact with the entire width of the specimen. Note: One method of inspection is to wrap a specimen of 55 mm × 10 mm × 10 mm tightly with thin paper (such as using tape) and place it on the specimen support. Wrap the blade of the impact knife tightly with carbon paper, with the carbon side facing outward (i.e., not facing the impact knife). Raise the pendulum so that it is at a small angle of a few degrees from the free hanging position, then release it and make contact with the specimen only once. The carbon paper should leave a completely cross-cut mark on the paper wrapped around the specimen. This test and the verification of the angle between the impact knife blade and the specimen when in contact (9.7) can be completed simultaneously. 8.6 The center of the pendulum impact knife and the center of the anvil span should differ by less than 0.5 mm. 8.7 When a lateral force approximately equal to 4% of the effective weight W of the pendulum (see Figure 4b) is applied at the point of impact, the axial play of the pendulum bearing measured at the impact knife should not exceed 0.25 mm
8.8 When a force of 150 N ± 10 N is applied at a distance of 1 and perpendicular to the plane of the pendulum's swing, the radial play of the shaft at the pendulum shaft bearing should not exceed 0.08mm.
Note: For example, when a force of about 150N is applied to the pendulum in a direction perpendicular to the swing plane, the radial clearance can be measured by the movement of the end of the indicating shaft (on the bearing) of the dial indicator fixed on the bearing seat of the frame. 8.9 For newly manufactured testing machines, it is recommended that the mass of the frame base is at least 12 times the mass of the pendulum. Note: The base of the testing machine refers to the part of the frame located below the horizontal support surface of the specimen support. 9 Pendulum
The following parameters should be determined for the inspection of the pendulum (including the impact knife): potential energy Ap
error of indicated energy A;
instantaneous impact speed of the pendulum;
energy absorbed by friction;
position of the strike center (i.e., the distance from the strike center to the axis of the pendulum shaft); e)
radius of curvature of the impact knife blade and the impact knife blade angle; g) angle between the contact line of the impact knife and the horizontal axis of the specimen. 9.1 The maximum allowable relative error between the potential energy Ar and the nominal energy A is ±1%. The test method of potential energy A is as follows: Use the knife bearing of a balance or a dynamometer to support the pendulum horizontally, select the distance 12 from the pendulum axis to the fulcrum, so that the straight line connecting the center of gravity of the pendulum and passing through the pendulum axis has a horizontality of at least 15/1000 [see Figure 4a), and the moment of the pendulum can be measured. The force F and the length 12 should be measured separately and accurately to ±0.2%. The moment M is the product F×12. Note 1: Length 1: can be equal to length 1,
The measurement of the falling angle α should be accurate to ±0.4°; this angle can be greater than 90°. The potential energy Ap is calculated as follows:
Ap = M(1 - cosa)
GB/T 38082002
Note 2: This formula and the contents of 9.2~9.1 are applicable to test machines with a device for measuring the falling angle and rising angle of the pendulum. For test machines with other indicating devices, other appropriate methods should be used. 9.2 The graduation marks on the dial corresponding to the values of absorbed energy of 0%, 10%, 20%, 30%, 50% or 60%, 80% of the nominal energy value shall be checked.
Lift the pendulum so that the pointer indicates each graduation mark, and then measure each angle of rise β to an accuracy of ±0.4°. Calculate the absorbed energy as follows:
Av = M(cosβ - cosα)
Note 1: Measuring I2, F and β with the specified measurement accuracy will result in an average total error in the measurement of A equal to approximately ±0.3% of the full scale value. The maximum permissible relative error between the indicated energy As and the absorbed energy Av calculated from the measured value shall be ±1% of the absorbed energy Av or ±0.5% of the potential energy Ap. In all cases, the larger value shall also satisfy the following conditions: Between 80% and 50% of the nominal energy A
[As = A|× 100% ≤ 1%
Less than 50% of the nominal energy A:
14s = Av|×100%≤0.5%
Note 2: In practice, it should be noted that the accuracy of the absorbed energy reading is inversely proportional to the magnitude of its value, especially when Av is very small compared to Ap. Absorbed energy values greater than 80% of the potential energy are inaccurate and should be recorded as approximate values. Note 3: This requirement is to ensure that the change in the strain rate of the specimen is less than 1 times for all tests. The strain rate of the specimen is a function of the pendulum velocity during the period of contact between the impact blade and the specimen; the pendulum velocity of the testing machine decreases as the specimen fractures. The change in pendulum velocity can be calculated by measuring the velocity before impact using the formula in 9.3 and measuring the velocity after impact using the same formula but replacing α with β (see Figure 4). 9.3 The impact velocity is determined by the following formula:
V = 2gl(1 -- cosa)
Where:
1--the distance from the axis of the pendulum shaft to the center of the specimen; g--free fall acceleration (its value can be taken as 9.81m/s2 to omit the measurement of the acceleration value of each test machine installation); α--fall angle (see Figure 4).
The impact velocity should be 5m/s~5.5m/s, but any value within the range of 3m/s~6m/s is allowed and should be noted in the report. 9.4 The energy absorbed by friction includes the energy lost by air resistance, bearing friction and pointer friction. These lost energies should be estimated as follows.
9.4.1 Determine the energy loss caused by pointer friction: Operate the test machine in the normal way, but do not place the specimen on the support, and record the angle of rise β indicated by the pointer, or the energy E1. Do not adjust the position of the pointer, then conduct a second test and record the angle of rise β or the energy reading E2. Thus, the energy loss force caused by the friction of the pointer during the rise of the pendulum is calculated by the following formula: When reading in angular units
p = M(cosp, — cosβ2)
When reading in energy units
p=E E2
The values of β, and β, or the values of E: and E should be the average of four measurements. 9.4.2 The energy loss caused by bearing friction and air resistance in a half cycle is determined as follows. After measuring β2 or E according to 9.4.1, place the pendulum in its initial position. Without re-adjusting the follower needle, release the pendulum without shock and vibration and allow it to swing for 10 half cycles. At the beginning of the 11th half cycle, adjust the follower needle to a position approximately equal to 5% of the full scale of the dial and record the value of β: or E:. The energy loss p caused by bearing friction and air resistance within half a cycle is calculated by the following formula: When the dial is scaled in angle units
When the dial is scaled in energy units
M(cosp: - cosp2)
(E— E,)
GB/T 3808—2002
Note: In actual tests, when the lift angle is β, if it is necessary to consider these energy losses, the value of P calculated by the following formula can be subtracted from the absorbed energy value: value: a+p
Because β and β are approximately equal to α, in practical applications, the value α+3 calculated by the following approximate formula can be subtracted
For testing machines scaled in energy units, the β value can be calculated by the following formula: β = arc cos[1 - 1/M(Ar - Av)]9.4.3 The total energy loss p+p caused by friction measured as above should not exceed 0.5% of the nominal energy Av. If the friction loss cannot be controlled within the tolerance after the error is exceeded and the friction loss of the pointer cannot be controlled within the tolerance, the bearing should be cleaned or replaced. 9.5 The distance l from the center of the strike to the axis of the pendulum shaft can be calculated by the period of the pendulum (the time of one swing), and the value should be 0.9951 ± 0.005l. The calculated value l should be accurate to 0.5mm. Make the pendulum swing at an angle not exceeding 5° and measure the time t of a complete cycle in seconds. Distance} is calculated by the following formula:
Where:
g——gravitational acceleration, value 9.81m/s3; yuan—value 9.87.
Therefore, l1=0.2485t, in meters (m). The measurement of t value should be accurate to within 0.1%.
·Note: For a pendulum with a period of approximately 2s, measure the time T required for 100 complete swings, repeat the measurement three times and calculate the average value. As long as the quantity characterizing its repeatability (Tmux-Tmin) is not greater than 0.2s, the measured t can meet the measurement accuracy requirements. 9.6 The dimensions of the impact knife should be checked. Either a 2 mm impact knife or an 8 mm impact knife can be used. The radius of curvature and the edge angle of the two types of impact knives are shown in Figure 2.
The maximum width of the part of the impact knife passing between the two anvils should be at least 10 mm but not greater than 18 mm. Note 1: One way to check the geometric dimensions of the impact knife is to make a sample for inspection. Note 2: Testing with a 2 mm impact knife and an 8 mm impact knife usually gives different results, so the type of impact knife must be specified in the corresponding standard. It is recommended to indicate the radius of curvature of the impact knife as a subscript in the model, such as CVN2 or CVNs. 9.7 The angle between the contact line of the impact knife and the horizontal axis of the specimen ("direction of the impact knife") should be 90°±2°. NOTE: One method of testing is to wrap a specimen measuring 55 mm x 10 mm x 10 mm tightly with thin paper (e.g. using adhesive tape) and place it on the specimen support. Wrap the blade of the impact knife tightly with carbon paper, with the carbon side facing outward (i.e. not facing the impact knife). Raise the pendulum to a small angle of a few degrees from the free hanging position, then release it and make contact with the specimen only once. The angle between the blade of the impact knife and the longer dimension of the specimen is determined by the impression left by the carbon paper on the paper wrapping the specimen. This test and the test (8.5) to ensure that the impact knife contacts the entire width of the specimen can be carried out at the same time.
9.8 The mechanism for releasing the pendulum in the initial position should operate freely and, when released, should not be affected by the initial pulse, and there should be no stagnation and lateral vibration. 9.9 If the testing machine is equipped with a braking mechanism, there should be means to prevent the pendulum from being accidentally braked. In addition, during the measurement of such factors as cycle and friction energy loss, it must be ensured that the braking mechanism is completely disconnected. 9.10 The structural design of the testing machine with automatic pendulum lifting device should be able to be directly inspected. 453
GB/T 3808-2002
) Anvil and support
The inspection of the anvil and support should include the following items (see Figure 2, Figure 3 and Table 3); the overall dimensions of the support;
the overall dimensions of the anvil;
the span of the brick base;
the inclination of the anvil;
the radius of curvature of the anvil;
f) the space when the broken specimen pops out of the testing machine. 10.1 The two supporting surfaces of the support should be parallel and the difference should not exceed 0.1mm. The support should make the parallelism between the axis of the specimen and the axis of the pendulum shaft within 3/1000.
10.2 The two supporting surfaces of the anvil should be parallel and the difference should not exceed 0.1mm. The angle between the planes on which the two bearing surfaces of the support and the planes on which the two bearing surfaces of the anvil are located shall be 90°±0.1°. The span of the anvil shall be (40) mm.
The radius of curvature of the anvil shall be (18\) mm.
The inclination of the anvil shall be 11°±1°
10.3 There shall be sufficient space to ensure that the broken specimen can fly freely away from the testing machine without hindrance as far as possible and prevent it from rebounding to the hammer before the pendulum ends its swing. The width of each part through which the pendulum passes between the anvils shall not exceed 18 mm. There are generally two basic types of hammers, see Figure 1. When using a C-type hammer, if the space at each end of the specimen is greater than 13 mm, the broken specimen will not rebound to the hammer. If an end positioner is used to place the specimen, it should be removed before impact. When using a U-type hammer, measures should be taken to prevent the broken specimen from rebounding to the hammer. For most testing machines using a U-shaped hammer, the shield should be designed and installed according to the following requirements (see Figure 3): a) thickness of about 1.5 mm; b) hardness not less than 45 HRC; c) radius of the internal corners at least 1.5 mm; d) when installed, the gap between the shield and the protruding part of the hammer body does not exceed 1.5 mm. Note In some testing machines, the opening inside the hammer body allows at least 13 mm of space between the end of the specimen (placed in the position to be tested) and the shield, then a) and d) are not required.
11 Indicating device
111 The inspection of analogue indicating devices shall include the following items a) inspection of the dial scale; b) inspection of the pointer.
Analogue indicating devices shall be calibrated in angular units or in energy units. The width of the dial scale shall be uniform and the width of the pointer shall be approximately equal to the scale width. The pointer shall be designed so that the reading is free of parallax. The resolution r of the indicating device is the ratio of the width of the pointer to the center distance between two adjacent scale lines (division interval). The recommended ratio is 1:4, 1:5 or 1:10. In order to estimate the scale division value to one tenth of the scale, the division interval is required to be not less than 2.5mm. The division value should not be greater than 1/100 of the nominal energy, and at least 0.25% of the nominal energy should be estimated. 11.2 The inspection of the digital indicating device shall ensure that the following requirements are met. The digital indicating device shall be calibrated in angle units or energy units. The resolution of the indicating device is considered to be an increment of the last significant digit of the digital indicator, provided that the change in the indicated value is not greater than one increment. When the change in the indicated value is greater than one increment, the resolution is considered to be half of the range of change. The resolution should be at least 1/400 of the nominal energy. 45.1
12 Indirect inspection using standard specimens
12.1 Indirect inspection is the inspection of specified points on the indicating device using standard specimens. These standard specimens are used to: a) compare the tests performed on the test machine to be inspected and the standard test machine; b) monitor the performance of the test machine throughout its entire service life without reference to any other test machine. GB/T 3808—2002
12.2 At least two absorption energy levels within the operating range of the test machine should be tested. The energy level of the standard sample should be within the operating range of the test machine and as close to its upper and lower limits as possible.
Note: When more than two energy levels of standard samples are selected, the other energy levels should be distributed as evenly as possible between the upper and lower limits of the standard samples. 12.3 The technical requirements for standard samples are specified in GB/T18658. 12.4 A simple direct test is recommended before indirect testing. This simple direct test should include: a) According to 7.2a) Check the testing machine;
b) Measure:
Bianstone seat; radius of curvature and span (see 10.2): Impact knife: blade radius of curvature,
position between anvils (see 9.6),
angle (only when replacing the impact knife), (see 9.7); friction energy loss of bearings and pointers;
energy loss of air resistance.
13 Inspection cycle
13.1 Direct and indirect inspections should be carried out after the testing machine is first installed or transported. 13.2 When replacing worn parts, the corresponding provisions of this standard should be followed. Direct inspection shall be carried out in accordance with relevant regulations. At the same time, indirect inspection shall also be carried out.
13.3 The inspection period of indirect inspection shall not exceed 12 months. 13.3.1 Indirect inspection may be required in one of the following situations: a) A large number of tests have been carried out;
The absorbed energy required to break certain special specimens is greater than the nominal energy; c) The quality control plan formulated by the laboratory requires indirect inspection. 13.3.2 After replacing the impact knife, indirect inspection shall be carried out. 13.4 When the results of indirect inspection are not satisfactory, direct inspection shall be carried out (see Chapter 1). A simple direct test should be performed before the indirect test (see 12.4).
13.5 Before using the testing machine every day, a simple direct test should be performed according to 9.4.1. This is because this simple direct test can quickly determine whether the performance of the testing machine has been reduced due to dirt in the bearings. 14 Error and repeatability
Avi, Av2, ... Avs are the absorbed energy values of a group of five standard specimens after breaking, arranged in order of increasing energy value. 14.1 Repeatability
Under the specified control conditions, the repeatability of the testing machine is expressed as; Repeatability == Avs → Avi, that is: Avmax — Avmin Table 2 gives the maximum allowable value of repeatability. 14.2 Error
Under the specified control conditions, the error of the testing machine is expressed as: Error = AV—AR
GB/T3808—2002
Where:
Ay_ Ay+Ava+Avs+Av.+Avs.
Ak——Standard energy value of the group of standard specimens. Table 2 gives the maximum allowable error values.
Maximum allowable value of repeatability and error
Energy level
15 Inspection report
The inspection report shall include at least the following contents: a)
Adoption of this standard;
Repeatability
Identification of the testing machine: manufacturer's name, model and number: radius of curvature of the impact knife blade;
User's name and installation address;
Name or logo of the inspection agency;
Inspection date;
Nominal value of the pendulum potential energy;
Identification of the standard specimens used for indirect inspection, including the standard values and measured energy values of these specimens; indirect inspection results;
Energy loss caused by air resistance and friction; repeatability;
Error,
Conclusion on whether the testing machine meets the requirements of this standard. 456
±10%Ak3 There should be enough space to ensure that the broken specimen can fly freely away from the testing machine without hindrance as much as possible, and prevent it from rebounding to the hammer before the pendulum ends its swing. The width of each part of the pendulum passing between the anvils should not exceed 18mm. There are generally two basic types of hammers, see Figure 1. When using a C-type hammer, if the space at each end of the specimen is greater than 13mm, the broken specimen will not rebound to the hammer. If an end positioner is used to place the specimen, it should be removed before impact. When using a U-type hammer, measures should be taken to prevent the broken specimen from rebounding to the hammer. Most testing machines using a U-type hammer should be designed and installed with a shield (see Figure 3) according to the following requirements: a) The thickness is about 1.5 mm: b) The hardness is not less than 45HRC; c) The radius of the internal corner is at least 1.5mm; d) When placed, the gap between the shield and the protruding part of the hammer does not exceed 1.5 mm. NOTE In some testing machines, the opening inside the hammer allows at least 13 mm of space between the end of the specimen (placed in the position to be tested) and the shield, then a) and d) are not required.
11 Indicator
111 The inspection of analogue indicating devices shall include the following items a) Inspection of the scale;
b) Inspection of the pointer.
Analogue indicating devices shall be calibrated in angular units or in energy units. The scale lines shall be uniform and the width of the pointer shall be approximately equal to the scale line width. The pointer shall be designed so that there is no parallax in the reading. The resolution r of the indicating device is the ratio of the width of the pointer to the center distance between two adjacent scale lines (division interval), and the recommended ratio is 1:4, 1:5 or 1:10; in order to estimate the scale division value to one tenth of the scale division value, the division interval is required to be not less than 2.5 mm. The division value shall not be greater than 1/100 of the nominal energy, and at least 0.25% of the nominal energy shall be estimated. 11.2 The inspection of digital indicating devices shall ensure that the following requirements are met. Digital indicating devices shall be calibrated in angular units or in energy units. The resolution of the indicating device is considered to be one increment of the last significant digit of the digital indicator, provided that the change in the indicated value is not greater than one increment. When the change in the indicated value is greater than one increment, the resolution is considered to be half of the range of variation. The resolution should be at least 1/400 of the nominal energy. 45.1
12 Indirect inspection using standard specimens
12.1 Indirect inspection is the inspection of specified points on the indicating device using standard specimens. These standard specimens are used to: a) compare tests performed on the test machine to be inspected and on the standard test machine; b) monitor the performance of the test machine throughout its entire life cycle without reference to any other test machine. GB/T 3808—2002
12.2 At least two absorption energy levels within the operating range of the test machine should be tested. The energy level of the standard sample should be within the operating range of the test machine and as close to its upper and lower limits as possible.
Note: When more than two energy levels of standard samples are selected, the other energy levels should be distributed as evenly as possible between the upper and lower limits of the standard samples. 12.3 The technical requirements for standard samples are specified in GB/T18658. 12.4 A simple direct test is recommended before indirect testing. This simple direct test should include: a) According to 7.2a) Check the testing machine;
b) Measure:
Bianstone seat; radius of curvature and span (see 10.2): Impact knife: blade radius of curvature,
position between anvils (see 9.6),
angle (only when replacing the impact knife), (see 9.7); friction energy loss of bearings and pointers;
energy loss of air resistance.
13 Inspection cycle
13.1 Direct and indirect inspections should be carried out after the testing machine is first installed or transported. 13.2 When replacing worn parts, the corresponding provisions of this standard should be followed. Direct inspection shall be carried out in accordance with relevant regulations. At the same time, indirect inspection shall also be carried out.
13.3 The inspection period of indirect inspection shall not exceed 12 months. 13.3.1 Indirect inspection may be required in one of the following situations: a) A large number of tests have been carried out;
The absorbed energy required to break certain special specimens is greater than the nominal energy; c) The quality control plan formulated by the laboratory requires indirect inspection. 13.3.2 After replacing the impact knife, indirect inspection shall be carried out. 13.4 When the results of indirect inspection are not satisfactory, direct inspection shall be carried out (see Chapter 1). A simple direct test should be performed before the indirect test (see 12.4).
13.5 Before using the testing machine every day, a simple direct test should be performed according to 9.4.1. This is because this simple direct test can quickly determine whether the performance of the testing machine has been reduced due to dirt in the bearings. 14 Error and repeatability
Avi, Av2, ... Avs are the absorbed energy values of a group of five standard specimens after breaking, arranged in order of increasing energy value. 14.1 Repeatability
Under the specified control conditions, the repeatability of the testing machine is expressed as; Repeatability == Avs → Avi, that is: Avmax — Avmin Table 2 gives the maximum allowable value of repeatability. 14.2 Error
Under the specified control conditions, the error of the testing machine is expressed as: Error = AV—AR
GB/T3808—2002
Where:
Ay_ Ay+Ava+Avs+Av.+Avs.
Ak——Standard energy value of the group of standard specimens. Table 2 gives the maximum allowable error values.
Maximum allowable value of repeatability and error
Energy level
15 Inspection report
The inspection report shall include at least the following contents: a)
Adoption of this standard;
Repeatability
Identification of the testing machine: manufacturer's name, model and number: radius of curvature of the impact knife blade;
User's name and installation address;bzxZ.net
Name or logo of the inspection agency;
Inspection date;
Nominal value of the pendulum potential energy;
Identification of the standard specimens used for indirect inspection, including the standard values and measured energy values of these specimens; indirect inspection results;
Energy loss caused by air resistance and friction; repeatability;
Error,
Conclusion on whether the testing machine meets the requirements of this standard. 456
±10%Ak3 There should be enough space to ensure that the broken specimen can fly freely away from the testing machine without hindrance as much as possible, and prevent it from rebounding to the hammer before the pendulum ends its swing. The width of each part of the pendulum passing between the anvils should not exceed 18mm. There are generally two basic types of hammers, see Figure 1. When using a C-type hammer, if the space at each end of the specimen is greater than 13mm, the broken specimen will not rebound to the hammer. If an end positioner is used to place the specimen, it should be removed before impact. When using a U-type hammer, measures should be taken to prevent the broken specimen from rebounding to the hammer. Most testing machines using a U-type hammer should be designed and installed with a shield (see Figure 3) according to the following requirements: a) The thickness is about 1.5 mm: b) The hardness is not less than 45HRC; c) The radius of the internal corner is at least 1.5mm; d) When placed, the gap between the shield and the protruding part of the hammer does not exceed 1.5 mm. NOTE In some testing machines, the opening inside the hammer allows at least 13 mm of space between the end of the specimen (placed in the position to be tested) and the shield, then a) and d) are not required.
11 Indicator
111 The inspection of analogue indicating devices shall include the following items a) Inspection of the scale;
b) Inspection of the pointer.
Analogue indicating devices shall be calibrated in angular units or in energy units. The scale lines shall be uniform and the width of the pointer shall be approximately equal to the scale line width. The pointer shall be designed so that there is no parallax in the reading. The resolution r of the indicating device is the ratio of the width of the pointer to the center distance between two adjacent scale lines (division interval), and the recommended ratio is 1:4, 1:5 or 1:10; in order to estimate the scale division value to one tenth of the scale division value, the division interval is required to be not less than 2.5 mm. The division value shall not be greater than 1/100 of the nominal energy, and at least 0.25% of the nominal energy shall be estimated. 11.2 The inspection of digital indicating devices shall ensure that the following requirements are met. Digital indicating devices shall be calibrated in angular units or in energy units. The resolution of the indicating device is considered to be one increment of the last significant digit of the digital indicator, provided that the change in the indicated value is not greater than one increment. When the change in the indicated value is greater than one increment, the resolution is considered to be half of the range of variation. The resolution should be at least 1/400 of the nominal energy. 45.1
12 Indirect inspection using standard specimens
12.1 Indirect inspection is the inspection of specified points on the indicating device using standard specimens. These standard specimens are used to: a) compare tests performed on the test machine to be inspected and on the standard test machine; b) monitor the performance of the test machine throughout its entire life cycle without reference to any other test machine. GB/T 3808—2002
12.2 At least two absorption energy levels within the operating range of the test machine should be tested. The energy level of the standard sample should be within the operating range of the test machine and as close to its upper and lower limits as possible.
Note: When more than two energy levels of standard samples are selected, the other energy levels should be distributed as evenly as possible between the upper and lower limits of the standard samples. 12.3 The technical requirements for standard samples are specified in GB/T18658. 12.4 A simple direct test is recommended before indirect testing. This simple direct test should include: a) According to 7.2a) Check the testing machine;
b) Measure:
Bianstone seat; radius of curvature and span (see 10.2): Impact knife: blade radius of curvature,
position between anvils (see 9.6),
angle (only when replacing the impact knife), (see 9.7); friction energy loss of bearings and pointers;
energy loss of air resistance.
13 Inspection cycle
13.1 Direct and indirect inspections should be carried out after the testing machine is first installed or transported. 13.2 When replacing worn parts, the corresponding provisions of this standard should be followed. Direct inspection shall be carried out in accordance with relevant regulations. At the same time, indirect inspection shall also be carried out.
13.3 The inspection period of indirect inspection shall not exceed 12 months. 13.3.1 Indirect inspection may be required in one of the following situations: a) A large number of tests have been carried out;
The absorbed energy required to break certain special specimens is greater than the nominal energy; c) The quality control plan formulated by the laboratory requires indirect inspection. 13.3.2 After replacing the impact knife, indirect inspection shall be carried out. 13.4 When the results of indirect inspection are not satisfactory, direct inspection shall be carried out (see Chapter 1). A simple direct test should be performed before the indirect test (see 12.4).
13.5 Before using the testing machine every day, a simple direct test should be performed according to 9.4.1. This is because this simple direct test can quickly determine whether the performance of the testing machine has been reduced due to dirt in the bearings. 14 Error and repeatability
Avi, Av2, ... Avs are the absorbed energy values of a group of five standard specimens after breaking, arranged in order of increasing energy value. 14.1 Repeatability
Under the specified control conditions, the repeatability of the testing machine is expressed as; Repeatability == Avs → Avi, that is: Avmax — Avmin Table 2 gives the maximum allowable value of repeatability. 14.2 Error
Under the specified control conditions, the error of the testing machine is expressed as: Error = AV—AR
GB/T3808—2002
Where:
Ay_ Ay+Ava+Avs+Av.+Avs.
Ak——Standard energy value of the group of standard specimens. Table 2 gives the maximum allowable error values.
Maximum allowable value of repeatability and error
Energy level
15 Inspection report
The inspection report shall include at least the following contents: a)
Adoption of this standard;
Repeatability
Identification of the testing machine: manufacturer's name, model and number: radius of curvature of the impact knife blade;
User's name and installation address;
Name or logo of the inspection agency;
Inspection date;
Nominal value of the pendulum potential energy;
Identification of the standard specimens used for indirect inspection, including the standard values and measured energy values of these specimens; indirect inspection results;
Energy loss caused by air resistance and friction; repeatability;
Error,
Conclusion on whether the testing machine meets the requirements of this standard. 456
±10%Ak2 At least two absorbed energy levels within the operating range of the testing machine should be tested. The energy level of the standard specimen should be within the operating range of the testing machine and as close to its upper and lower limits as possible.
Note: When more than two energy levels of standard specimens are selected, the other energy levels should be evenly distributed between the upper and lower limits of the standard specimens as much as possible. 12.3 The technical requirements for standard specimens are specified in GB/T18658. 12.4 A simple direct test is recommended before indirect testing. This simple direct test should include: a) Check the testing machine according to 7.2a);
b) Measure:
Bianstone seat; radius of curvature and span (see 10.2): Impact knife: blade radius of curvature,
position between the anvils (see 9.6),
angle (only when the impact knife is replaced), (see 9.7); friction energy loss of bearings and pointers;
air resistance energy loss.
13 Inspection cycle
13.1 Direct and indirect inspections shall be carried out after the testing machine is installed or moved for the first time. 13.2 When replacing worn parts, direct inspection shall be carried out in accordance with the relevant provisions of the corresponding clauses of this standard. At the same time, indirect inspection shall also be carried out.
13.3 The inspection cycle of indirect inspection shall not exceed 12 months. 13.3.1 Indirect inspection may be required in any of the following situations: a) a large number of tests have been carried out;
The absorbed energy required to break certain special specimens is higher than the nominal energy; c) the quality control plan established by the laboratory requires indirect inspection. 13.3.2 Indirect inspection shall be carried out after replacing the impact knife. 13.4 When the results of indirect inspection are not satisfactory, direct inspection shall be carried out (see Chapter 1). A simple direct inspection shall be carried out before indirect inspection (see 12.4).
13.5 Before using the testing machine every day, a simple direct inspection should be carried out according to 9.4.1. This is because this simple direct inspection can quickly determine whether the performance of the testing machine has been reduced due to dirt in the bearings. 14 Error and repeatability
Avi, Av2, ... Avs are the absorbed energy values of a group of five standard specimens after breaking, arranged in the order of increasing energy values. 14.1 Repeatability
Under the specified control conditions, the repeatability of the testing machine is expressed as; Repeatability == Avs → Avi, that is: Avmax — Avmin Table 2 gives the maximum allowable value of repeatability. 14.2 Error
Under the specified control conditions, the error of the testing machine is expressed as: Error = AV—AR
GB/T3808—2002
Where:
Ay_ Ay+Ava+Avs+Av.+Avs.
Ak——Standard energy value of the group of standard specimens. Table 2 gives the maximum allowable error values.
Maximum allowable value of repeatability and error
Energy level
15 Inspection report
The inspection report shall include at least the following contents: a)
Adoption of this standard;
Repeatability
Identification of the testing machine: manufacturer's name, model and number: radius of curvature of the impact knife blade;
User's name and installation address;
Name or logo of the inspection agency;
Inspection date;
Nominal value of the pendulum potential energy;
Identification of the standard specimens used for indirect inspection, including the standard values and measured energy values of these specimens; indirect inspection results;
Energy loss caused by air resistance and friction; repeatability;
Error,
Conclusion on whether the testing machine meets the requirements of this standard. 456
±10%Ak2 At least two absorbed energy levels within the operating range of the testing machine should be tested. The energy level of the standard specimen should be within the operating range of the testing machine and as close to its upper and lower limits as possible.
Note: When more than two energy levels of standard specimens are selected, the other energy levels should be evenly distributed between the upper and lower limits of the standard specimens as much as possible. 12.3 The technical requirements for standard specimens are specified in GB/T18658. 12.4 A simple direct test is recommended before indirect testing. This simple direct test should include: a) Check the testing machine according to 7.2a);
b) Measure:
Bianstone seat; radius of curvature and span (see 10.2): Impact knife: blade radius of curvature,
position between the anvils (see 9.6),
angle (only when the impact knife is replaced), (see 9.7); friction energy loss of bearings and pointers;
air resistance energy loss.
13 Inspection cycle
13.1 Direct and indirect inspections shall be carried out after the testing machine is installed or moved for the first time. 13.2 When replacing worn parts, direct inspection shall be carried out in accordance with the relevant provisions of the corresponding clauses of this standard. At the same time, indirect inspection shall also be carried out.
13.3 The inspection cycle of indirect inspection shall not exceed 12 months. 13.3.1 Indirect inspection may be required in any of the following situations: a) a large number of tests have been carried out;
The absorbed energy required to break certain special specimens is higher than the nominal energy; c) the quality control plan established by the laboratory requires indirect inspection. 13.3.2 Indirect inspection shall be carried out after replacing the impact knife. 13.4 When the results of indirect inspection are not satisfactory, direct inspection shall be carried out (see Chapter 1). A simple direct inspection shall be carried out before indirect inspection (see 12.4).
13.5 Before using the testing machine every day, a simple direct inspection should be carried out according to 9.4.1. This is because this simple direct inspection can quickly determine whether the performance of the testing machine has been reduced due to dirt in the bearings. 14 Error and repeatability
Avi, Av2, ... Avs are the absorbed energy values of a group of five standard specimens after breaking, arranged in the order of increasing energy values. 14.1 Repeatability
Under the specified control conditions, the repeatability of the testing machine is expressed as; Repeatability == Avs → Avi, that is: Avmax — Avmin Table 2 gives the maximum allowable value of repeatability. 14.2 Error
Under the specified control conditions, the error of the testing machine is expressed as: Error = AV—AR
GB/T3808—2002
Where:
Ay_ Ay+Ava+Avs+Av.+Avs.
Ak——Standard energy value of the group of standard specimens. Table 2 gives the maximum allowable error values.
Maximum allowable value of repeatability and error
Energy level
15 Inspection report
The inspection report shall include at least the following contents: a)
Adoption of this standard;
Repeatability
Identification of the testing machine: manufacturer's name, model and number: radius of curvature of the impact knife blade;
User's name and installation address;
Name or logo of the inspection agency;
Inspection date;
Nominal value of the pendulum potential energy;
Identification of the standard specimens used for indirect inspection, including the standard values and measured energy values of these specimens; indirect inspection results;
Energy loss caused by air resistance and friction; repeatability;
Error,
Conclusion on whether the testing machine meets the requirements of this standard. 456
±10%Ak
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