ISO 9330-6 pdf download – Welded steel tubes for pressure purposes -Technical delivery conditions – Part 6: Longitudinally welded austenitic stainlesssteel tubes.
8 Technical delivery conditions
8.1 Appearance and soundness
8.1.1 The surface condition of the tube is at the option of the manufacturer. However, the purchaser may specify one of the surface conditions indicated in table 6 or another condition, as required.
8.1.2 The tubes shall be clean and free from such defects as can be established by visual inspection in accordance with this part of ISO 9330 (see 9.7).
8.1.3 The tubes shall have a finish and surface condition which permits surface imperfections or marks requiring dressing to be identified.
NOTE — Any special requirements for surface condition should be agreed between the purchaser and the manufacturer at the time of enquiry and order.
8.1.4 It shall be permissible to dress by grinding or machining surface marks and imperfections such as scabs, seams, tears, laps, slivers or gouges, provided that the thickness of the tube after dressing does not fall below the nominal thickness by more than the tolerance specified in this part of ISO 9330. Repair by welding is not permitted.
Weld defects in tubes welded by a process using filler metal may be repaired at the option of the manufacturer, but tubes shall be repaired only before heat treatment or cold finishing respectively; except that defects found after initial heat treatment may be repaired provided that such tubes are heat treated again. The repaired regions shall be non-destructively tested; in addition, the tube shall be tested for leak tightness.
8.1.5 Surface imperfections which encroach on the minimum wall thickness shall be considered as defects and shall be deemed not to comply with this part of ISO 9330.
8.1.6 All dressed areas shall blend smoothly into the contour of the tube.
8.1.7 Tubes welded without the addition of filler metal shall, unless otherwise agreed between the parties concerned, be dressed flush externally at the weld, so that the tube appears smooth and circular to the eye.
The internal projection of the weld bead shall be within 10 % of the specified thickness, with a minimum of 0,5 mm and a maximum of 3 mm.
A misalignment of the abutting edges shall not exceed:
— for wall thickness T 12,7 mm: 1,6 mm;
— for wall thickness T> 12,7 mm: 0,125 T or 3 mm, whichever is the smaller.
8.1.8 For tubes welded with the addition of filler metal and supplied in the as-welded or welded and heat-treated condition, the outside and inside weld reinforcement shall not exceed the following maximum height:
— for the external weld bead: 0,5 Tor 3 mm, whichever is the smaller;
— for the internal weld bead: 0,25 Tor 3 mm, whichever is the smaller.
9.4.1.5 Location and orientation of the test pieces
9.4.1.5.1 Test piece for the tensile test
The test piece for the tensile test is either a full tube section or a test piece taken in a direction either longitudinal or transverse to the axis of the tube, in accordance with the requirements of ISO 6892.
At the manufacturer’s option:
— for tubes with an outside diameter less than or equal to 219.1 mm. the test is carried out either on a tube section or on a test piece taken in a direction longitudinal to the axis of the tube;
— for tubes with an outside diameter greater than 219,1 mm, the test piece is taken in a direction either longitudinal or transverse to the axis of the tube.
9.4.1.5.2 Test piece for the tensile test on the weld
The test piece for the tensile test on the weld shall be taken transverse to the weld, with the weld at the centre ot the test piece. The test piece shall be a strip section with the full thickness of the tube, and the weld bead may be removed.
9.4.1.5.3 Test piece for the flattening test
The test piece for the flattening test shall consist of a tube section, in conformity with ISO 8492. This test shall not apply for tubes with an outside diameter above 400 mm.
9.4.1.5.4 Test piece for the bend test
The test piece for the bend test shall consist of a section cut from the tube in accordance with the requirements of ISO 7438. For tubes with a wall thickness greater than 20 mm, the test piece may consist of a segment in a transverse direction, with rectangular section, 38 mm wide and 19 mm thick.
9.4.1.5.5 Test piece for the drift or ring expanding test or ring tensile test
The test piece for the drift or ring expanding test or ring tensile test consists of a tube section in conformity with
ISO 8493, ISO 8495 or ISO 8496, respectively. This test shall not apply for tubes with an outside diameter above
400 mm.
9.4.1.5.6 Test pieces for the impact test
Impact testing may be agreed upon at the time of ordering. If so, a set of three ISO V-notch full size (10 mm x 10 mm) test pieces shall be taken from each sample tube transverse to the tube axis, provided that the dimension of the tube permits this without flattening of the test piece; otherwise, the test pieces shall be taken longitudinal to the tube axis.
The test pieces shall be taken and prepared in such a way that the axis of the notch is perpendicular to the surface of the tube.
ISO 9330-6 pdf download – Welded steel tubes for pressure purposes -Technical delivery conditions – Part 6: Longitudinally welded austenitic stainlesssteel tubes
