ASTM-A1012:10(R2021) pdf free download – Standard Specification for Seamless and Welded Ferritic, Austenitic and Duplex Alloy Steel Condenser and Heat Exchanger Tubes With Integral Fins.
7. Temper
7.1 The tube after enhancing shall normally be supplied in the as-finned temper. When specified by the purchaser, for bending, coiling or other fabricating operations, enhanced portions of the tube may be stress relief annealed or solution annealed.
7.2 Heat treatment of enhanced sections, or bend areas, or both, shall be in accordance with the governing plain tube specification.
8. Chemical Composition
8.1 The tubing specified shall conform to the chemical requirements prescribed in the governing plain tube specification.
9. Tensile Requirements
9.1 The tube prior to the finning operation, or unenhanced portions of the tinned tube, shall conform to the requirements for tensile properties prescribed in the governing plain tube specification.
10. Permissible Variations in Dimensions
10.1 Diameter—The outside diameter of the unenhanced sections shall not exceed the diameter tolerances shown in the governing plain tube specification as measured by micrometers and verified by “go” and “no go” ring gages. The diameter over the enhanced sections shall not exceed the diameter of the plain sections involved, as determined by a “go” ring gage unless otherwise specified. The dimensions of the ring gages shall be as described in 10.1.1 and 10.1.2.
10. 1. 1 The inside diameter dimension of the “go” ring gage shall be equal to the nominal tube diameter, plus the maximum tolerance, plus 0.002 in. The length of the “go” ring gage shall be 1 in. (25.4 mm) minimum.
10.1.2 The inside diameter dimension of the “no go” ring gage shall be equal to the nominal tube diameter minus the maximum tolerance. The length of the “no go” ring gage shall be 1 in. (25.4 mm) minimum.
10.2 Wall Thickness—The wall thickness of enhanced and unenhanced sections shall not exceed the thickness tolerances shown in the governing plain tube specification unless otherwise agreed to between the manufacture and purchaser. No tube at any point shall be less than the minimum thickness specified in the plain sections or in the enhanced sections.
10.3 Length—The length of the tubes shall not be less than that specified, but may exceed the specified value by the amounts given in Table 1.
10.3.1 The length of plain ends, as measured from the tube end to the first tool impression, shall not be less than that specified, but may exceed the specified value by ½ in. (12.7 mm).
10.3.2 The length of tin sections and lands (unenhanced portions) shall be as specified ± ¼ in. (6.35 mm).
10.4 Squareness tfCit—The angle of cut of the end of any tube may depart from square by not more than 0.016 in.
10.5 Straightness—The tube shall he reasonably straight and free of bends or kinks.
ii. Workmanship, Finish, and Appearance
11.1 Finished tubes shall be clean and free of foreign material, shall have smooth ends free of burrs, and shall be free of injurious external and internal imperfections. Minor defects may be removed, provided the dimensional tolerances of Section 10 are not exceeded.
11 .2 A slight amount of oxidation on the surface resulting from heat treatment after enhancing or bending is acceptable. When the plain tube specification allows for a slight amount of oxidation on the surface resulting from heat treatment, this also is acceptable.
12. Nondestructive Tests
12.1 After enhancing operations, subject each tube to a nondestructive electromagnetic test, and either a pneumatic or hydrostatic test as specified in the purchase order. Tubes normally shall be tested in the as-fabricated condition but, at the option of the manufacturer or purchaser, may he tested in the stress relief annealed condition.
12. 1. 1 Eddy Current Test—Eddy current inspect the tube by passing it through an encircling coil designed to test the entire cross section of the tube.
12.1.1.1 The reference standard used to adjust the sensitivity setting of the apparatus shall he sound and of the same nominal alloy, enhanced configuration. condition (temper). and nominal dimensions as the lot of tubes to be tested on a production basis. Drill four holes not larger than 0.03 1 in. (0.787 mm) in diameter radially through the enhanced wall in each of four successive planes at 0°, 90°, 180°, and 270°. Use a suitable drill jig to guide the drill, taking care to avoid distortion of the adjacent fins. Locate one hole in the weld for welded material. Space artificial discontinuities at least 16 in.