Information on the most widely used ASTM standards within the materials testing industry
tensile/ impact/ torsion test sample
Charpy impact test verification specimens, (also called impact reference specimens, impact standard specimens) are physical standards with stable, uniform, and certified impact energy values determined by authoritative organizations. They are mainly used to check and verify the accuracy of impact testing machines, rather than directly testing the performance of regular materials.
General introduction
Charpy impact test verification specimens, (also called impact reference specimens, impact standard specimens) are physical standards with stable, uniform, and certified impact energy values determined by authoritative organizations. They are mainly used to check and verify the accuracy of impact testing machines, rather than directly testing the performance of regular materials.
Core Definition and Uses:
• Essence: It is a certified reference material (CRM) and is considered a 'physical standard.' Its reference impact energy value is rigorously validated and comes with a certificate.
• Main Purpose: It serves as an indirect verification tool. By comparing the impact energy measured by the testing machine with the standard value on the specimen's certificate, you can determine if the machine is accurate (errors usually need to be within 1%).
• Difference: Unlike ordinary 'impact specimens' (made from the material to be tested), impact reference specimens are made of special materials with stable properties, cannot be used up casually, and must be periodically traced back to their standard values.
Impact reference blocks R2 R8
10mm x 20mm x 100mm
Steel block, with a 10mm deep V-shaped groove with a 30° angle, R values of 2mm and 8mm respectively, milled in the middle of the 100mm length;
Inspection item: Apply force to the pendulum impact point: choose the V-groove R2 thrust block for a blade with R2 impact curvature; choose the V-groove R8 thrust block for a blade with R8 impact curvature.
Standard V-notch impact specimen
Size: 55mm x 10mm x 10mm
The standard energy value of the standard impact specimen should fall within the following ranges:
Low energy (L) level: standard energy value < 30J
Medium energy (M) level: 30J ≤ standard energy value < 110J
High energy (H) level: 110J ≤ standard energy value < 220J
Ultra-high energy (UH) level: standard energy value > 220J
Standard impact specimen
Energy < 40J, standard deviation ≤ 2J
Energy ≥ 40J, standard deviation ≤ 5%
Inspection item: impact energy
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Key Features
Notch Types: Mainly divided into Charpy V-notch and Charpy U-notch. The V-notch is more widely used because it is more sensitive to material brittleness.
Material Requirements: Usually made of highly pure, uniformly structured alloy steels (like 40CrNiMo, 4340 steel, etc.) and undergo special heat treatment to ensure consistency between batches.
Specifications and Dimensions: Follow international standards (such as ISO 148, ASTM E23), with typical dimensions of 10mm×10mm×55mm. The notch depth and angle have strict tolerance requirements.
ISO 148-1:2016
Metallic materials - Charpy pendulum impact test - Part 1: Test method
ASTM E23-25
Standard Test Methods for Notched Bar Impact Testing of Metallic Materials
ISO 148-2:2016
Metallic materials - Charpy pendulum impact test - Part 2: Verification of testing machines
GB/T 3808
Verification of pendulum-type impact testing machines
ISO 148-3:2016
Metallic materials. Charpy pendulum impact test. Preparation and characterization of Charpy V-notch test pieces for indirect verification of pendulum impact machines
Main technical specification Impact test sample:
| Arc Curved Notch type | Standard | Energy value | Energy Level | Mark |
| Arc Curved notch | R2 | 28.6J | Low energy | 5 pcs/set |
| R2 | 81.9J | Middle energy | 5 pcs/set | |
| R2 | 127J | High energy | 5 pcs/set | |
| R2 | 232J | Super high energy | 5 pcs/set | |
| R8 | 29.6J | Low energy | 5 pcs/set | |
| R8 | 93J | Middle energy | 5 pcs/set | |
| R8 | 142J | High energy | 5 pcs/set | |
| R8 | 266J | Super high energy | 5 pcs/set | |
| V notch | LV2 | 20.7J | Low energy | 5 pcs/set |
| MV2 | 107.8J | Middle energy | 5 pcs/set | |
| HV2 | 155.9J | High energy | 5 pcs/set | |
| LV8 | 13.6J | Low energy | 5 pcs/set | |
| MV8 | 106.1J | Middle energy | 5 pcs/set | |
| HV8 | 160J | High energy | 5 pcs/set |
Tensile test reference samples
| Type | Specification | Original gauge length | Parallel length | Maximum force | Head size | Tensile strength | Yield strength | For machine | Mark |
| Tensile samples of bars at room temperature | Φ5mm | 25mm | 30mm | 13KN | M12mm | 650MPa | 382MPa | 100KN or less | 5 pc/set |
| Φ10mm | 50mm | 60mm | 52KN | M16mm | 650MPa | 390MPa | 300KN or less | 5 pc/set | |
| Φ15mm | 75mm | 85mm | 120KN | Φ20mm | 720MPa | 440MPa | 200-600KN | 5 pc/set | |
| Φ25mm | 125mm | 150mm | 330KN | Φ32mm | 710MPa | 400MPa | 500-2000KN | 5 pc/set | |
| Tensile Samples of rebar | Φ16mm | 80mm | 450mm | 100KN | Φ16mm | 680MPa | 525MPa | 150-500KN | 5 pc/set |
| Φ12mm | 60mm | 400mm | 60KN | Φ12mm | 580MPa | 430MPa | 5 pc/set | ||
| Φ18mm | 80mm | 450mm | 15KN | Φ18mm | 599MPa | 439MPa | 5 pc/set |
| Type | Specification | Original gauge length | Parallel length | Parallelism | Roughness | Modulus of Elasticity (E) | Material | Mark |
| Tensile modulus of elasticity quality control sample of metallic material | Φ10mm | 100mm | 120mm | 0.005mm | 0.8μm | 73.5 GPa | Aluminum alloy | 3 pc/set |
| Φ10mm | 100mm | 120mm | 0.005mm | 0.8μm | 203.6 GPa | Steel | 3 pc/set |
| Type | Specification | Original gauge length | Parallel length | Maximum force | Head size | Tensile strength | For machine | Mark |
| Tensile sample with a thin strip at room temperature | 0.3X12.5mm | 50mm | 2KN | 20mm | 300MPa | 20KN or less | 5 pc/set | |
| Sheet standard samples | 1.2X20mm | 80mm | 120mm | 8KN | 35mm | 295.5MPa | 5 pc/set | |
| Tensile sample of high-strength steel sheet | 1.2X20mm | 80mm | 120mm | 35mm | 800- 900MPa | 5 pc/set | ||
| Aluminum alloy sheet tensile sample | 3X12.5mm | 50mm | 60mm | 20mm | 433MPa | 5 pc/set |

Standard
ISO 148-3 core focus is to establish unified rules for manufacturing, qualification, certification and proper use of Charpy V-notch reference test pieces, which are essential for the indirect verification of Charpy impact machines as required by ISO 148-2.
ISO 148-1 defines the method for the Charpy (V-notch & U-notch) pendulum impact test to determine the absorbed energy when a notched metallic specimen is broken by a single swinging pendulum blow. It does not cover instrumented impact testing (that belongs to ISO 14556).
ISO 148-2 specifically formulated for the verification, calibration and performance inspection of Charpy pendulum impact testing machines used in Charpy impact tests per ISO 148-1.
ASTM E23 covers both Charpy (simple‑beam) and Izod (cantilever‑beam) notched-bar impact tests. It applies to all metallic materials for impact tests using pendulum machines.
ASTM E2298 dedicated to instrumented Charpy V-notch (CVN) and miniaturized Charpy V-notch (MCVN) impact tests for metallic materials. Instead of only obtaining a single absorbed energy value, this standard extracts force, displacement and segmented energy parameters to analyze the full fracture process.
ISO 14556 applies exclusively to instrumented Charpy V-notch pendulum impact tests for all metallic materials. It captures real-time force-displacement curves and a full set of dynamic characteristic parameters.
EN 10045‑1 regulates the Charpy simple-beam pendulum impact test for metallic materials, covering both V-notch and U-notch specimens. It defines unified rules for specimen preparation, machine requirements, operating conditions and result reporting.
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