ISO 2573-1977 PDF

Full title and description

ISO 2573:1977 — Tensile testing systems — Determination of K-value. This International Standard specifies a method for determining the apparent elastic compliance (K‑value) of tensile testing systems used when a nearly constant extension rate is required during increase of force; it describes required test pieces, test conditions and the procedure to obtain the K‑value for a tensile testing system at ambient temperature.

Abstract

ISO 2573:1977 defines how to measure the K‑value (apparent elastic compliance, i.e. deflection per unit force) of tensile testing systems so that machines that cannot directly control extension rate can be characterized and used reliably for determining yield properties. The method uses a suitable test piece and compares extension rates in the elastic region and during yield under near‑constant force conditions; the ratio is used to calculate the system K‑value. The standard was published in 1977 and is currently recorded as withdrawn.

General information

• Status: Withdrawn (withdrawal recorded in ISO registry; no direct replacement indicated in the ISO record).
• Publication date: 31 July 1977 (Edition 1, 1977-08).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 77.040.10 — Mechanical testing of metals.
• Edition / version: Edition 1 (1977).
• Number of pages: 6 pages.

Scope

Specifies a laboratory method to determine the K‑value (apparent elastic compliance) of tensile testing systems whose mobile gripping system moves at approximately constant speed during the measurements. The procedure is intended for systems used to determine yield limits where direct control of extension rate is required but not always available; it describes specimen selection and preparation, machine conditions, measurement of extension rates in the elastic and yield regions, and calculation of the K‑value for the operative elastic range at ambient temperature.

Key topics and requirements

• Definition of K‑value: apparent elastic compliance of the testing system (deflection per unit force) determined from a tensile test.
• Requirements for suitable test pieces: material and preparation that produce a clear transition from elastic to plastic behavior (or adequately strain‑hardened specimens).
• Measurement procedure: measuring extension rates in the elastic region (ve) and during yielding at near‑constant force (vp), then using the ratio of these rates to compute K for the specified test conditions.
• Machine applicability: machines with adjustable crosshead position, certain mechanical drives (with negligible speed loss), and some hydraulic drives with very low leakage; conditions for ensuring near‑constant extension rate are described.
• Test conditions: ambient temperature, operative elastic range definition, and cautionary notes on variables (force range, machine construction) that affect the K‑value.

Typical use and users

Used by materials testing laboratories, calibration and validation laboratories, manufacturers and maintainers of tensile testing machines, and standards bodies that need to characterise machine compliance for reliable determination of yield properties and controlled strain‑rate tests. It is primarily a technical procedure for test engineers and metrologists responsible for machine set‑up, verification and intercomparison.

Related standards

ISO 2573 references other tensile testing and machine calibration documents relevant to the method (for example ISO standards on tensile testing of steel and specific specimen types). In the standard's text several ISO test method standards (such as those for tensile testing of steel sheets, wires and tubes) and related guidance documents are listed as normative or informative references.

Keywords

tensile testing, K‑value, machine compliance, elastic compliance, tensile testing systems, extension rate, yield measurement, ISO 2573, mechanical testing of metals.

FAQ

Q: What is this standard?

A: ISO 2573:1977 is an International Standard that specifies a method for determining the K‑value (apparent elastic compliance) of tensile testing systems used when a nearly constant extension rate is required.

Q: What does it cover?

A: It covers specimen selection and preparation, the measurement of extension rates in the elastic and yielding regions, calculation of the system K‑value, and the machine conditions required to obtain valid results (ambient temperature, operative elastic range, applicable machine types).

Q: Who typically uses it?

A: Materials testing laboratories, calibration and verification engineers, manufacturers of testing machines, and standards organizations involved in mechanical testing of metals.

Q: Is it current or superseded?

A: The ISO bibliographic record lists ISO 2573:1977 as withdrawn. The ISO record shows the withdrawal stage; no direct replacement is indicated in the ISO entry. Users should consult current ISO/TC 164 publications or national standards bodies for any modern replacement methods.

Q: Is it part of a series?

A: It is part of ISO work on mechanical testing of metals and was developed under the relevant ISO technical committees (initially ISO/TC 17 and later under ISO/TC 164/SC 1). It is related to other ISO tensile testing standards referenced in its normative references.

Q: What are the key keywords?

A: K‑value, compliance, tensile testing, extension rate, elastic range, yield, tensile testing systems.