AS 1391:2020 pdf download.Metallic materials一Tensile testing一 Method of test at room temperature.
6 Test pieces
6.1 Shape and dimensions
6.1.1 General
The shape and dimensions of the test pieces may be constrained by the shape and dimensions of the metallic product from which the test pieces are taken.
The test piece Is usually obtained by machining a sample from the product or a pressed blank or casting. However, products of uniform cross-section (sections, bars, wires, etc.) and also as-cast test pieces (i.e. for cast iron and non-ferrous alloys) may be tested without being machined.
The cross-section of the test pieces may be circular, square, rectangular, annular or, in special cases, some other uniform cross-section.
Preferred test pieces have a direct relationship between the original gauge length, L0, and the original cross-sectional area, S0. expressed by the formula L0 = kJ , where k is a coefficient of proportionality,
and are called proportional test pieces. The internationally adopted value for k is 5,65. The original gauge length shall be not less than 15 mm. When the cross-sectional area of the test piece is too small for this requirement to be met with, k = 5,65, a higher value (preferably 11,3) or a non-proportional test piece may be used.
NOTE By using an original gauge length smaller than 20 mm, the uncertainty of the result “elongation after fracture” will be increased.
For non-proportional test pieces, the original gauge length, L0. is independent of the original cross- sect ional area, S0.
The dimensional tolerances of the test pieces shall be in accordance with the Annexes B to E (see 6.2).
Other test pieces such as those specified in relevant product standards or national standards may be used by agreement with the customer, e.g. ISO 3183111, (API 51), ISO 11960121, (API 5CT), ASTM A370(61, ASTM E8ML7I, DIN 501251101, IACS W2I’l, and IlS Z 2241l’l.
6.1.2 Machined test pieces
Machined test pieces shall incorporate a transition radius between the gripped ends and the parallel length if these have different dimensions. The dimensions of the transition radius are important and it is recommended that they be defined in the material specification if they are not given in the appropriate annex (see 6.2).
The gripped ends may be of any shape to suit the grips of the testing machine. The axis of the test piece shall coincide with the axis of application of the force.
The parallel length, L, or, in the case where the test piece has no transition radii, the free length between the grips, shall always be greater than the original gauge length, L0.
6.1.3 Unmachined test pieces
lithe test piece consists of an unmachined length of the product or of an unmachined test bar, the free length between the grips shall be sufficient for gauge marks to be at a reasonable distance from the grips (see Annexes B to C).
As-cast test pieces shall incorporate a transition radius between the gripped ends and the parallel length. The dimensions of this transition radius are important and it is recommended that they be defined in the product standard. The gripped ends may be of any shape to suit the grips of the testing machine provided that they enable the centre of the test piece to coincide with the axis of application of force. The parallel length, Lc shall always be greater than the original gauge length, Lo.AS 1391 pdf download.