ASTM E647-24 PDF

Full title and description

Standard Test Method for Measurement of Fatigue Crack Growth Rates — ASTM E647-24. This test method specifies procedures for determining fatigue crack growth rates (da/dN) as a function of the crack‑tip stress‑intensity factor range (ΔK) for metallic materials and describes specimen configurations, measurement techniques, test procedures, and recommended data reduction and reporting practices used in fatigue‑crack‑growth testing.

Abstract

ASTM E647-24 provides a unified set of procedures to measure fatigue crack growth rates from near‑threshold through unstable growth (Kmax‑controlled) using linear elastic fracture mechanics. Multiple test procedures and specimen geometries are included so users can select the appropriate method for the expected growth‑rate regime. The standard also addresses environmental effects (including aqueous testing), non‑visual crack measurement methods, and recommended data‑reduction/analysis practices.

General information

• Status: Active
• Publication date: June 24, 2024 (E647‑24)
• Publisher: ASTM International
• ICS / categories: 77.040.10 — Mechanical testing of metals; Committee E08 (Metals — Mechanical testing).
• Edition / version: ASTM E647‑24
• Number of pages: 52 pages

Bibliographic and status details above are taken from the ASTM document record and standard catalog listings.

Scope

This test method covers determination of fatigue‑crack‑growth rates (da/dN versus ΔK) for metallic materials across a wide growth‑rate range (near‑threshold through region of unstable growth). Several specimen types and test procedures are provided so testing can be adapted for different growth‑rate regimes and material constraints; thickness or strength are not limiting factors provided specimen geometry and size keep the specimen predominantly elastic. The standard includes requirements and guidelines for apparatus, specimen preparation, crack‑length measurement, data reduction, reporting, and precision/bias statements, plus annexes for specimen types and special environmental testing.

Key topics and requirements

• Measurement objective: determination of fatigue‑crack‑growth rate (da/dN) as a function of stress‑intensity factor range (ΔK) and reporting d a/dN versus ΔK curves and threshold behavior.
• Specimen types and geometries: compact tension (C(T)), middle‑crack tension, single‑edge notch bend, M(T), and other calibrated specimen forms (annexes provide details and calibrations).
• Test procedures: various procedures (constant‑amplitude, load‑reduction/load‑shedding, load‑increasing) to suit differing growth‑rate regimes and to determine threshold and stable growth behavior.
• Crack measurement methods: visual measurement, clip gages/compliance, electric potential difference (EPD), and other non‑visual techniques with guidance on calibration and use.
• Data reduction and interpretation: recommended d a/dN calculation methods, ΔK computation, consideration of force ratio (R) and Kmax effects, and guidance on crack‑closure and other shielding influences.
• Environmental testing: special requirements and procedures for testing in aqueous environments and for controlling environment‑related effects on growth rates.
• Reporting, precision, and bias: required reporting items, recommended data presentation, and precision/bias information to assess result quality and comparability.

These key topics and clause structure follow the E647‑24 content and annex/appendix organization.

Typical use and users

ASTM E647 is used by materials and mechanical testing laboratories, aerospace and automotive component engineers, metallurgists, R&D groups, failure investigators, quality assurance teams, and standards organizations. Typical applications include material characterization for fatigue‑crack propagation resistance, development and validation of fracture‑mechanics‑based life predictions, comparative material testing, and qualification of structural alloys and components under cyclic loading.

Related standards

Commonly referenced or complementary standards include ASTM E399 (plane‑strain fracture toughness), ASTM E1820 (measurement of fracture toughness and crack‑growth resistance), ASTM E466/E606 (fatigue testing practices/methods), and ISO standards for fatigue testing (for example ISO 12108). Users frequently consult these documents together when designing fracture and fatigue test programs.

Keywords

fatigue crack growth; da/dN; ΔK; stress‑intensity factor range; threshold; crack‑closure; compact tension; specimen calibration; crack‑length measurement; fatigue testing; fracture mechanics.

FAQ

Q: What is this standard?

A: ASTM E647‑24 is the Standard Test Method for Measurement of Fatigue Crack Growth Rates; it defines procedures, specimen types, measurement techniques, and reporting practices for obtaining fatigue crack‑growth data (da/dN vs ΔK).

Q: What does it cover?

A: It covers test procedures from near‑threshold growth through Kmax‑controlled instability, multiple specimen geometries and measurement methods (visual, compliance, electric potential), environmental testing considerations (e.g., aqueous), and recommended data reduction, reporting, and precision statements.

Q: Who typically uses it?

A: Materials testing labs, aerospace and automotive engineers, R&D and qualification teams, metallurgists, and failure‑analysis professionals use E647 to generate reliable fatigue‑crack‑growth data for materials and components.

Q: Is it current or superseded?

A: As of the publication/update date shown in the ASTM record, E647‑24 is the current active edition (published/last updated June 24, 2024). Users should always verify the ASTM document record for any later revisions or corrigenda.

Q: Is it part of a series?

A: E647 is part of the body of ASTM standards addressing fatigue and fracture mechanics (including E399, E1820, E466/E606 and related practices); it is commonly used in series with fracture‑toughness and fatigue testing standards to fully characterize material behavior under cyclic and fracture loading.

Q: What are the key keywords?

A: Key keywords are fatigue crack growth, da/dN, ΔK, stress‑intensity factor, threshold, crack measurement, compact tension (C(T)), specimen calibration, crack closure, and fracture mechanics.