ISO 148-3:2016 download.Metallic materials — Charpy pendulum impact test — Part 3: Preparation and characterization of Charpy V-notch test pieces for Indirect verification of pendulum impact machines.
The suitability of a pendulum impact testing machine for acceptance testing of metallic materials has usually been based on a calibration of its scale and verification of compliance with specified dimensions. such as the shape and spacing of the anvils supporting the test piece. The scale calibration is commonly verified by measuring the mass of the pendulum and Its elevation at various scale readings. This procedure for evaluation of machines had the distinct advantage of requiring only measurements of quantities that could be traced to national standards. The objective nature of these traceable measurements minimized the necessity for arbitration regarding the suitability of the machines for material acceptance tests.
However, sometimes two machines that had been evaluated by the direct-verification procedures described above, and which met all dimensional requirements, were found to give significantly different impact values when testing test pieces of the same material.
This difference was commercially important when va]ues obtained using one machine met the material specification, while the values obtained using the other machine did not. To avoid such disagreements. some purchasers of materials added the requirement that all pendulum impact testing machines used for acceptance testing of material sold to them should be indirectly verified by testing reference test pieces supplied by them. A machine was considered acceptable only it the values obtained using the machine agreed. within specified limits, with the value furnished with the reference test pieces.
Successful experience in the use of reference test pieces led to the requirement in ISO 148-2 that Indirect verification should be performed using reference test pieces in addition to direct verification. Other standards and codes also require indirect verification using reference test pieces; for example. EN 10045.2(11 (now obsolete) and ASTM E231Z1 require the use of reference test pieces. The purpose of this part of ISO 148 Is to specify the requirements, preparation and methods for qualifying test pieces used for the Indirect verification of pendulum Impact testing machines.
1 Scope
This part of ISO 148 specifies the requirements. preparation and methods for qualifying test pieces used for the indirect verification of pendulum impact testing machines In accordance with ISO 148-2.
It specifies notched test pieces with nominal dimensions identical to those specified in ISO 148-1; however, the tolerances are more stringent.
NOTE 1 The chemical composition or heat treatment, orboth. are varied according to the energy level desired.
NOTE 2 Reference test pieces are qualitied on reference pendulum impact testing machines which are also
descnbcd in this part of ISO 148.
2 Normative references
The following referenced documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendmeiits) applies.
ISO 148-1. Metallic materials — Charpy pendulum tmpact test — Part 1; Test method
ISO 148•2, Metallic materials — Charpypendidum impact test — Part 2: Verification of testing machines
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 DefInitions pertaining to the machine
3.1.1
industrial machine
pendulum impact resting machine used for industrial, general or most research-laboratory testing of metallic materials
Note ito cigry; These machines are not used to establish reference values.
3.1.2
reference machine
pendulum impact testing machine used to determine certified values for batches of reference test pieces
3.2 DefinitIons pertaining to energy
3.2.1
total absorbed energy
Kr
total absorbed energy required to break a test piece with a pendulum Impact testing machine, which is not corrected for any losses of energy
Note ito entry: ft is equal to the difference in the potentiil energy from the starting position of the pendulum to the end of the first hail swing during which the test piece is broken.
3.2.2
absorbed energy
K
energy required to break a test piece with a pendulum impact testing machine, after correction for energy losses
Note 1 to entry: The letter V or Ii La used to Indicate the notch geometry. I.e. KVor KU. The number 2 or RI-s used as a subscript to Indicate the radius nithe striking edge oIthe striker, for example KV.
3.2.3
reference absorbed energy
Kit
certified value of absorbed energy assigned to the test pieces used to verily the performance of pendulum Impact testing machines
3.3 Definitions related to groups of test pieces
3.3.1
batch
definite quantity of reference test pieces manufactured under identical conditions of production, with a common certified absorbed energy
3.3.2
set
group of test pieces chosen at random from a hatch
3.3.2.1
characterization set
set of test pieces taken from a batch and used to determine the reference energy of the batch
3.3.2.2
reference set
set of test pieces used to verify a pendulum impact testing machine
3.4 Definitions pertaining to test pieces
3.4.1
width
w
distance between the notched face and the opposite face
Note Ito entry: In previous versions of the ISO 148 series (prior to 2016). the distance between the notched face and the opposite face was specified as height. Changing this dimension to widLb makes ISO 1481 consistent with the terminology used in other ISO fracture standards.
5.1.5 Vibration
Ensure that the reference machine is not subpected to external vthrations induced by other equipment in close proximity, such as forging hammers, presses, moving vehides. The machine shall also be free of excessive vibrations during an impact test.
NOTE Such vibrations can be detected by placing a small container of water at any convenient location on the machine framework: the absence of ripples on the water surface during an impact test Indicates that this requirement has been met Excessive vibration In a machine firmly fastened to the floor indicates the need for a separate foundation and/or the use of vibration isolators.
5.1.6 Energy-Indicating mechanism
The resolution shall be at least 1/400 of the nominal energy.
5.2 Verification of reference testing machine
Direct verification shall be carried out in accordance with ISO 148-2 and with the additional requirements oFS,1,
Indirect verification shall be carried out using certified reference test piece. The repeatability and the bias shall be as specified in Table 3.
All equipment used for inspection and verification of a reference testing machine shall be calibrated and shall have a certified traceability to the SI System (the international system of units). The body performing the verification shall maintain calibration records for all inspection, measurement and test equipment.
The dates and details of all Inspections and repairs shall be documented and maintained for each reference machine by the owner of the machine.