ISO 8491 pdf download

ISO 8491 pdf download.Metallic materials — Tube (in full section) — Bend test 1 Scope This International Standard specifies a method for determining the ability of full-section metallic tubes of circular cross-section to undergo plastic deformation in bending. It is intended for tubes with an outside diameter no greater than 65 mm, although the range of the outside diameter for which this International Standard is applicable may be more exactly specified in the relevant product standard. NOTE — Bend tests of the test pieces taken from tubes in the form of transverse strips should be made in accordance with ISO 7438 so as to increase the original curvature of the test piece. 2 Symbols, designations and units Symbols, designations and units for the bend test of tubes in full section are given in table 1 and are shown in figure 1 . 3 Principle Bending a straight tube in full section around a grooved former of a specified radius r until the angle of bend a (see figure 1 ) reaches the value specified in the relevant product standard. 4 Testing equipment 4.1 Tube-bending machines, designed to prevent the section of the tube from becoming oval. The tube bend former of the machine shall have a groove corresponding in profile to the outside diameter of the tube. The radius at the bottom of the groove shall be specified in the relevant product standard. NOTE — The tolerance of radius r, the depth and ovality of the groove, all have an effect on the test result. 5 Test piece The test piece shall be a portion of a straight tube of any length which will allow the test to be carried out on the tube-bending machine. 6 Procedure 6.1 In general, the test shall be carried out at ambient temperature within the limits of 1 0 °C to 35 °C. The test carried out under controlled conditions shall be made at a temperature of (23 ± 5) °C. 6.2 Bend the unfilled test piece of the tube by means of a tube-bending machine, ensuring contact between the test piece and the tube bend former over the length of bend, until the specified angle of bend is reached. 6.3 If welded tubes are subjected to the test, the position of the weld shall be at 90° to the plane of bending i.e. the neutral axis, unless otherwise indicated in the relevant product...