⚙️ Tensile Test of Steel

Construction PN-EN ISO 6892-1

Overview

STATUS (as of 02.11.2026). PN-EN ISO 6892-1:2020-05 — Polish version, published 30.08.2022, implements EN ISO 6892-1:2019 and ISO 6892-1:2019 [IDT]; it replaced PN-EN ISO 6892-1:2016-09 (Polish and English versions). The card has no withdrawal note — the standard is current; ISO 6892-1:2019 (third edition, 15.11.2019) has been confirmed by ISO (stage 90.93). The 2019 edition is a minor revision of the 2016 edition: the title of a referenced standard, the designation “coefficient of determination”, Formula (1) and the wording of several subclauses were corrected.

SCOPE AND PRINCIPLE (clauses 1, 5). The standard specifies the method for tensile testing of metallic materials and defines the mechanical properties that can be determined at room temperature; Annex A contains recommendations for computer-controlled testing machines. The test involves straining a test piece by tensile force, generally to fracture, to determine one or more of the properties defined in Clause 3. It is carried out at room temperature between 10 °C and 35 °C, unless otherwise specified, and under controlled conditions at (23 ± 5) °C. Outside the range 10–35 °C the temperature is recorded and reported, and the laboratory assesses the impact of such conditions. The modulus of elasticity, if requested, is determined according to Annex G.

PROPERTIES DETERMINED (clause 3). Stress R is the force divided by the original cross-sectional area So. Tensile strength Rm corresponds to the maximum force Fm (for materials with discontinuous yielding — the highest force after the beginning of work-hardening). The upper yield strength ReH is the maximum stress prior to the first decrease in force, and the lower yield strength ReL — the lowest stress during plastic yielding, ignoring initial transient effects. Proof strength Rp (e.g. Rp0.2) is the stress at which the plastic extension measured with an extensometer equals a specified percentage of the extensometer gauge length; Rt — the same for total extension. The percentage elongation after fracture A is the permanent elongation of the gauge length after fracture (Lu − Lo) as a percentage of Lo — the pieces of the test piece are carefully fitted back together so that their axes lie in a straight line — and the percentage reduction of area Z = (So − Su) / So · 100 %. For properties based on extension (e.g. Rp, Ae, Ag) the use of an extensometer is mandatory.

TEST PIECES (clause 6). The shape and dimensions of the test piece may follow from the product; the test piece is usually machined from the product, a pressed blank or a casting, while products of uniform cross-section (sections, bars, wire) and as-cast test pieces may be tested without machining. The cross-section may be circular, square, rectangular, annular or, in special cases, another uniform shape. Proportional test pieces are preferred: Lo = k · √So, where k = 5.65 (the internationally adopted value); Lo shall be not less than 15 mm, and when the cross-section is too small for this, a higher k (preferably 11.3) or a non-proportional test piece is used. The types and tolerances of test pieces are given in the annexes: B — thin products (sheets, strips, flats) 0.1 mm to 3 mm thick, C — wire, bars and sections with a diameter or thickness of less than 4 mm, D — sheets and flats at least 3 mm thick and wire, bars and sections with a diameter or thickness of at least 4 mm, E — tubes. A machined test piece has a transition radius between the gripped ends and the parallel length, its axis coincides with the axis of force application, and the parallel length Lc (or the free length between the grips) is always greater than Lo. By agreement with the customer, other test pieces may be used, e.g. from product standards.

TESTING RATE (introduction; clause 10 outside the available text). The standard has two methods: A — based on strain rate (including strain rate estimated from the crosshead separation rate) and B — based on stress rate, used only in the elastic range. Method A is intended to minimize the variation of test rates at the moment when strain-rate-sensitive properties are determined and to minimize the measurement uncertainty, so the standard strongly recommends it. According to the description of the standard by a manufacturer of testing machines, method A has two variants: A1 — automatic strain rate control using the extensometer signal (closed loop) and A2 — preselection of the crosshead speed at which the required strain rate is achieved (open loop); the strain rate tolerance is 20 % of the set value.

APPARATUS (clause 2; classes — according to the testing machine manufacturer). The standard references ISO 7500-1 (calibration of the force-measuring system of the machine) and ISO 9513 (calibration of extensometers). According to the machine manufacturer, at least class 1 is required for the force-measuring system, an extensometer of at least class 1 for determining Rp, Rt and the slope of the initial part of the curve, and of at least class 2 for the other properties with greater extension (Ae, Ag, Agt, extension at fracture).

WHAT WE DO NOT GIVE HERE. The values of the strain rate and stress rate ranges for individual properties (10.3), the rules for setting the force zero point and gripping (10.1–10.2), the details of determining individual properties (clauses 11–21), the content of the test report and the measurement uncertainty (clauses 22–23) or the test piece dimensions from Annexes B–E — the available text of the standard ends at 6.2. Nor do we give any obligation to test in inspection documents or requirements for steel grades — these are set by product standards and order conditions, not by this standard.

Method principle

A test piece of known original dimensions (So, Lo) is strained axially in a testing machine, generally to fracture, at a temperature between 10 °C and 35 °C, while recording force and extension (for Rp, Ae and Ag — with an extensometer). Among other properties, ReH and ReL or Rp (e.g. Rp0.2) and Rm = Fm / So are determined, and after fracture — the elongation A = (Lu − Lo) / Lo · 100 % and the reduction of area Z = (So − Su) / So · 100 %. The testing rate is set by method A (strain rate; strongly recommended) or method B (stress rate in the elastic range).

Applications

• Determination of the mechanical properties of metallic materials at room temperature (scope of the standard)
• Thin products, wire, bars, sections, sheets and tubes — types of test pieces in Annexes B–E
• Tests according to product standards — other test pieces by agreement with the customer (6.1.1)
• Determination of the modulus of elasticity — when requested, according to Annex G
• Tests on computer-controlled machines — recommendations of Annex A

Key parameters

Standard

Standard number

PN-EN ISO 6892-1:2020-05

Title (PL)

Metale — Próba rozciągania — Część 1: Metoda badania w temperaturze pokojowej

Title (EN)

Metallic materials — Tensile testing — Part 1: Method of test at room temperature

Step-by-step procedure

1. Sampling and preparation of the test piece

   Machine the test piece from the product, a pressed blank or a casting (products of uniform cross-section and as-cast test pieces may be tested without machining). Type and tolerances according to Annexes B–E; a machined test piece has a transition radius, and the parallel length Lc is greater than Lo (clause 6).

2. Gauge length

   For a proportional test piece Lo = 5.65 · √So, not less than 15 mm (for a small cross-section k = 11.3 or a non-proportional test piece); mark the gauge length on the test piece (6.1.1, clause 8).

3. Original dimensions

   Determine the original cross-sectional area So of the parallel length (clause 7 — details outside the available text).

4. Gripping

   Grip the test piece so that its axis coincides with the axis of force application; for determining Rp, Ae and Ag attach an extensometer (6.1.2, 3.5).

5. Choice of testing rate method

   Method A (strain rate; variant A1 controlled by the extensometer signal or A2 with a preselected crosshead speed) or method B (stress rate in the elastic range); the standard strongly recommends method A. Rate values — according to 10.3 of the standard (introduction; variants A1/A2 — according to the machine manufacturer description).

6. Straining

   Strain at a temperature between 10 °C and 35 °C (under controlled conditions (23 ± 5) °C), generally to fracture, recording force and extension (clause 5).

   🌡 Temperature: 10–35 °C

7. Determination of properties

   Determine the required properties: ReH (maximum stress before the first decrease in force), ReL (lowest stress during yielding, without transient effects) or Rp (e.g. Rp0.2), and Rm = Fm / So (clause 3).

8. After fracture

   Carefully fit the pieces of the test piece together so that their axes lie in a straight line, measure Lu and the minimum cross-sectional area Su; calculate A = (Lu − Lo) / Lo · 100 % and Z = (So − Su) / So · 100 % (3.1.2, 3.4.2, 3.8).

9. Test report

   Report the results and test conditions; outside the range 10–35 °C record the temperature. The full content of the test report is given in clause 22 (outside the available text) (clause 5).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The available text of the standard contains no safety requirements — rules for working at the testing machine (grips, fracture of the test piece) are set by the laboratory on the basis of a risk assessment

Frequently asked questions