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IS 1608:2005 Part 1 is the Indian Standard (BIS) for mechanical testing of metals - tensile testing - part 1: method of test at room temperature. This standard outlines the method for tensile testing of metallic materials at room temperature to determine essential mechanical properties such as yield strength, tensile strength, and percentage elongation.
Specifies the method for tensile testing of metallic materials at room temperature.
! Ensure the extensometer is accurately calibrated and firmly attached to prevent slippage during testing, which could result in an inaccurate yield point.
! Loading rate must be strictly controlled according to the standard, especially within the elastic range, to ensure reliable yield strength results.
! When preparing machined test pieces, ensure smooth transitions at the shoulders to avoid stress concentrations and premature failure outside the gauge length.
Metallic materials - Tensile testing at ambient temperature
IS 1608:2005 was a dual-numbered standard, technically identical to ISO 6892:1998.
ISO 6892-1:2019ISO
HighCurrent
Metallic materials — Tensile testing — Part 1: Method of test at room temperature
This is the direct modern successor in the ISO system. It introduces significant changes, primarily in testing speed control.
ASTM E8 / E8M - 22ASTM International
HighCurrent
Standard Test Methods for Tension Testing of Metallic Materials
The primary North American standard for the same purpose. While the fundamental principles are identical, it differs in test specimen geometry and speed control specifications.
EN ISO 6892-1:2019CEN
HighCurrent
Metallic materials - Tensile testing - Part 1: Method of test at room temperature
The European adoption of the ISO standard, making it the mandatory standard for tensile testing in EU member states. It is technically identical to ISO 6892-1:2019.
Key Differences
≠IS 1608:2005 specifies test speed primarily based on stress rate (Method B in modern ISO standards). Modern equivalents like ISO 6892-1 strongly recommend Method A, which is closed-loop strain rate control using an extensometer, for better repeatability and lower uncertainty.
≠IS 1608:2005, following the old ISO standard, primarily uses proportional test pieces where the gauge length is a function of the cross-sectional area (L₀ = 5.65√S₀). In contrast, ASTM E8/E8M predominantly specifies standard test pieces with fixed gauge lengths (e.g., 50 mm or 2 inches) regardless of the cross-section.
≠Modern standards like ISO 6892-1:2019 contain specific requirements and annexes for computerized testing systems, including data acquisition rates and digital signal processing, which were not detailed in the 2005 Indian standard.
≠The requirements for extensometer class and its calibration (as per ISO 9513) are more explicitly linked to the properties being measured in modern standards. For example, a Class 1 or better extensometer is typically required for accurate proof strength determination.
Key Similarities
≈All standards are based on the identical fundamental principle of applying a uniaxial tensile load to a specimen until fracture to determine key mechanical properties.
≈The definitions and methods for determining core properties like Ultimate Tensile Strength (UTS), Elongation after Fracture (A), and Reduction of Area (Z) are conceptually the same across all standards.
≈The definition of proof strength (non-proportional elongation), particularly at the 0.2% offset (Rp0.2 or YS0.2%), is a harmonized concept and value used consistently in all listed standards.
≈The specified ambient temperature range for conducting the test is consistent, typically defined as being between 10 °C and 35 °C, with a default of 23 ± 5 °C if not otherwise specified.
Parameter Comparison
Parameter
IS Value
International
Source
Primary Test Control Method
Stress Rate Control
Strain Rate Control (Method A, recommended)
ISO 6892-1:2019
Test Speed in Elastic Region (for Steel)
Stress rate: 20 to 60 MPa/s
Strain rate: 0.00025 s⁻¹ (± 20%)
ISO 6892-1:2019 (Method A)
Test Specimen Proportionality Constant (k)
5.65 (for L₀ = k√S₀)
Not primarily used; fixed gauge lengths (e.g., 50mm, 2in)
ASTM E8 / E8M - 22
Standard Round Specimen Gauge Length (for 12.5 mm dia.)
~62.5 mm (5D)
50 mm (4D)
ASTM E8 / E8M - 22
Proof Strength Offset (Standard)
0.2 %
0.2 %
ISO 6892-1:2019, ASTM E8 / E8M - 22
Room Temperature Range
10 °C to 35 °C
10 °C to 35 °C
ISO 6892-1:2019
Test Speed in Plastic Range (after yield)
Strain rate related to parallel length, ≤ 0.008 s⁻¹
Strain rate related to extensometer gauge length, 0.0067 s⁻¹ (± 20%)
ISO 6892-1:2019 (Method A)
⚠ Verify details from original standards before use
Key Values4
Quick Reference Values
standard testing temperature10 °C to 35 °C
strictly controlled temperature23 ± 5 °C
proportional gauge length factor5.65
alternative gauge length factor11.3
Key Formulas
L0 = 5.65 * √S0 — Standard proportional gauge length
Rm = Fm / S0 — Tensile strength (where Fm is maximum force)
A = ((Lu - L0) / L0) * 100 — Percentage elongation after fracture
Tables & Referenced Sections
Key Tables
Table 1 - Symbols and designations
Annexes B to E - Dimensions of test pieces for different product types
Key Clauses
Clause 6 - Test piece specifications
Clause 9 - Determination of original cross-sectional area (S0)
Clause 10 - Marking the original gauge length (L0)
Clause 11 - Accuracy of testing apparatus
Clause 13 - Determination of percentage elongation after fracture