AS 1528.1:2019 pdf download.Stainless steel tubes and tube fittings for food processing and hygienic applications Part 1: Tubes.
3 Terms and definitions
No terms and definitions are listed in this document.
4 Working pressure
Non-shock maximum working pressure for a tube shall be 10 bar at temperatures from – 20 °C up to 100°C, subject to the engineering requirements of the specific application.
5 Materials
Tubes shall be made from an austenitic stainless steel cold-rolled strip, conforming to the chemical and mechanical properties specified for the relevant grade in ASTM A240M.
6 Process of manufacture
The tubes shall be welded by an inert gas-protected fusion process without the use of a filler rod.
7 Condition of delivery
Tubes 31.75 mm diameter and larger shall be provided in either the cold-worked, or cold-worked annealed condition, as specified prior to manufacturing. The weld shall be cold-worked. Tubes smaller than 31.75 mm diameter may be supplied without cold-working of the inner weld bead. NOTE For critical applications using smaller diameter tubes, seamless tubes or cold worked options may be required.
8 Dimensions and tolerances
8.1 Outside diameter and wall thickness
Nominal outside diameter and wall thicknesses for standard sizes are shown in Table 1. Tube diameter tolerances shall be those specified in Table 1 and wall thickness tolerance shall be ±10 % of nominal wall thickness. Other non-standard sizes may be manufactured to this specification; the outside diameter tolerance for the next larger size in Table 1 shall apply. Ovality is the difference between the maximum and minimum outside diameters measured at any one
cross-section. The maximum and minimum outside diameters of any cross-section shall not deviate from the nominal diameter by more than twice the permissible variation in outside diameter; however, the mean diameter at that cross-section shall be within the given permissible variation.
8.2 Length
The standard tube length shall be a 6 m mill-length or a mill-length nominated prior to manufacturing. For mill-lengths up to and including 7.3 m, the length tolerance shall be +35, 0 mm. For mill-lengths above 7.3 m, an additional length tolerance of +1 mm per additional 1 m of mill-length, up to a maximum length tolerance of +48, 0 mm. Off-line cut length tolerances shall be +3, 0 mm for tube diameters to 34.93 mm, and +5, 0 mm for tube diameters larger than 34.93 mm.
8.3 Ends
Ends shall be cut square and deburred.
8.4 Straightness
Each tube shall be straight within 2 mm in any 1000 mm length as measured against a straight edge.
9 Tube welds
All tube welds shall have 100 % weld penetration. Tubes with an outside diameter of 31.75 mm and above, shall have the internal weld bead cold-worked. The internal weld bead should be kept to a minimum for tubes with outside diameters below 31.75 mm.
10 Surface finish
10.1 External surface
The external surface of tubes may be as-produced or buff polished as specified. The surface finish shall be agreed upon by methods which may include comparison samples, Ra limits or grit specification.
10.2 Internal surface
10.2.1 General
Internal surface weld heat tint shall be no more than level 3 in AWS D18.1M, commonly referred to as “pale straw”. The requirements for pickling and any subsequent finishing may be specified (see Appendix A). Acceptance criteria of 16 % rule as set out in Iso 4288 shall apply for surface finish evaluation purposes.
10.2.2 Interior surface finish (excluding the weld zone)
The finish of the interior surface of the tube, excluding the weld zone, shall be a maximum 0.80 im Ra as assessed in accordance with the procedure described in ISO 4288. Any visual markings such as scoring or roll marks shall not have an Rt value exceeding 14.0 urn, or a single value either side of the nominal line of the roughness profile exceeding 7.0 lIm, referred to Rp (peak) and Rv (valley).
10.2.3 Interior surface finish (of the weld zone)
For tubes with an outside diameter 31.75 mm and above, the profile of the weld bead after cold working — shall be continuously smooth when visually inspected; and when measured laterally (across the weld) shall not have an Rt value exceeding 14.0 urn, or a single value either side of the nominal line of the roughness profile exceeding 7.0 urn, referred to Rp (peak) and Rv (valley).
11 Hygienic requirements
11.1 Absence of contaminants
Tubing shall be manufactured and handled in a manner that will avoid ferrous and other organic or inorganic contamination.
11.2 Freedom from defects
The tubes shall be internally clean and smooth. They shall be free from harmful surface defects, inclusions and longitudinal grooving.AS 1528.1 pdf download.