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IS 1757:1988 is the Indian Standard (BIS) for methods of charpy impact test for metallic materials. This standard prescribes the method for conducting the Charpy impact test (V-notch and U-notch) on metallic materials to evaluate their impact toughness and absorbed energy. It specifies standard test piece dimensions, notch geometry, and the procedure for testing under controlled temperatures.
Specifies the method for conducting the Charpy impact test on metallic materials.
! Notch preparation is highly critical; machining marks or improper root radii act as stress concentrators and can artificially lower the impact toughness value.
! Always record the test temperature alongside the impact energy, as the ductile-to-brittle transition makes impact properties highly temperature-dependent.
Metallic materials — Charpy pendulum impact test — Part 1: Test method
Defines the Charpy pendulum impact test method for determining absorbed energy in metallic materials.
ASTM E23-23ASTM International (US)
HighCurrent
Standard Test Methods for Notched Bar Impact Testing of Metallic Materials
Covers notched-bar impact testing of metallic materials using Charpy and Izod test methods.
EN ISO 148-1:2016CEN (European)
HighCurrent
Metallic materials - Charpy pendulum impact test - Part 1: Test method
European adoption of ISO 148-1, specifying the Charpy pendulum impact test for metals.
JIS Z 2242:2018JISC (Japan)
HighCurrent
Metallic materials -- Charpy pendulum impact test method
Specifies the test method for determining the impact value of metallic materials by the Charpy impact test.
Key Differences
≠IS 1757:1988 specifies wider dimensional tolerances for test pieces compared to modern standards like ISO 148-1. For example, the V-notch root radius tolerance is ±0.05 mm in IS 1757, versus a tighter ±0.025 mm in ISO 148-1.
≠The tolerance for maintaining the test temperature is less stringent in the Indian standard. IS 1757 allows a tolerance of ±2°C, while both ISO 148-1 and ASTM E23 mandate a stricter tolerance of ±1°C for tests at non-ambient temperatures.
≠Modern international standards like ASTM E23 and ISO 148-1 have comprehensive and mandatory procedures for both direct (dimensional, etc.) and indirect (testing of certified reference specimens) verification of the testing machine. The requirements in IS 1757:1988 are less detailed and rigorous.
≠While IS 1757 mentions V-notch, U-notch, and Keyhole notches, it does not explicitly require the reporting of supplementary data such as percentage shear fracture or lateral expansion, which are often mandatory or strongly recommended in current versions of ASTM E23 and ISO 148-1.
Key Similarities
≈The fundamental test principle is identical: measuring the energy absorbed by a standard notched specimen upon being struck by a swinging pendulum.
≈The nominal dimensions of the standard test specimen are the same across all standards: 55 mm in length with a 10 mm x 10 mm square cross-section.
≈All standards specify the use of similar notch types, most commonly the V-notch (45° angle, 2 mm deep) and the U-notch (or keyhole notch), as the primary geometries for creating stress concentration.
≈The specified velocity of the pendulum striker at the moment of impact is consistent, falling within the range of 5 to 5.5 m/s in both IS 1757 and the key international standards.
Parameter Comparison
Parameter
IS Value
International
Source
V-Notch Root Radius Tolerance
0.25 ± 0.05 mm
0.25 ± 0.025 mm
ISO 148-1:2016
Test Temperature Tolerance (Non-ambient)
± 2 °C
± 1 °C
ASTM E23-23
Anvil Span Tolerance
40 +0.5 / -0 mm
40 ± 0.05 mm
ISO 148-1:2016
Striker Tip Radius Tolerance (for V-notch)
2 to 2.5 mm (a range, not a tolerance)
2.0 ± 0.05 mm
ISO 148-1:2016
Ligament Depth Tolerance (V-notch)
8 ± 0.1 mm
8 ± 0.025 mm
ISO 148-1:2016
Angle between Specimen and Anvils
90° ± 0.5°
90° ± 0.1°
ISO 148-1:2016
⚠ Verify details from original standards before use
Key Values7
Quick Reference Values
Standard test piece length55 mm
Standard test piece cross-section10 mm x 10 mm
V-notch angle45 degrees
V-notch depth2 mm
Radius at base of V-notch0.25 mm
U-notch depth5 mm
Pendulum striking velocity5.0 to 5.5 m/s
Key Formulas
K = Absorbed energy (Joules) calculated from the difference in pendulum height before and after impact
Tables & Referenced Sections
Key Tables
Table 1 - Tolerances on Specified Dimensions of Test Piece
Key Clauses
Clause 4 - Principle
Clause 5 - Test Pieces
Clause 6 - Testing Machine
Clause 7 - Procedure
Frequently Asked Questions3
What are the dimensions of a standard Charpy V-notch specimen?+
55 mm in length with a 10 mm x 10 mm square cross-section and a 2 mm deep V-notch.
Can I test materials thinner than 10 mm?+
Yes, sub-size specimens with widths of 7.5 mm, 5 mm, or 2.5 mm are permitted for thinner materials.
What is the standard striking velocity of the pendulum?+
The pendulum should strike the specimen with a velocity between 5.0 m/s and 5.5 m/s.