ASME SA-557 SA-557M-2021 pdf free.SPECIFICATION FOR ELECTRIC-RESISTANCE- WELDED CARBON STEEL FEEDWATER HEATER TUBES.
6. Surface Condition 6.1 Finished tubes shall be free of scale but may have a superficial oxide film on the surfaces. A light-oxide scale on the outside and inside surfaces of U-bend shall be allowed for tubes which have been heat treated for relief of stress. 6.2 Finished tubes shall be coated on both outside and inside diameter with a thin paraffin oil to prevent corrosion in transit. Other types of coatings may be applied as mutu- ally agreed upon and specified in the order.
7. Chemical Composition 7.1 The steel shall conform to one of the requirements as to chemical composition as prescribed in Table 1. 7.2 For all tubes, the steel shall be fully killed. 7.3 When a grade is ordered under this specification, supplying an alloy grade that specifically requires the addi- tion of any element other than those listed for the ordered grade in Table 1 is not permitted.
8. Product Analysis 8.1 When requested in the purchase order, a product analysis shall be made by the supplier from one tube or coil of steel per heat. 8.2 If the original test for product analysis fails, retests of two additional lengths of flat-rolled stock or tubes, shall be made. Both retests, for the elements in question shall meet the requirements of this specification; otherwise all remaining material in the heat shall be rejected or, at the option of the producer, each length of flat-rolled stock or tube may be individually tested for acceptance. Lengths of flat-rolled stock or tubes which do not meet the require- ments of this specification shall be rejected. 8.3 For referee purposes, Methods E 30 shall be used.
10. Permissible Variations in Dimensions 10.1 Permissible variations from the specified outside diametershallbeinaccordancewiththeapplicable portions ofSpecification A 450/A 450M. The height offlash on the inside ofhot-rolled tubes shall be as specified in Specifica- tion A 450/A 450M. Cold-drawn tubes shall have no dimensional indication of welding flash. Tolerances for diameterandwall thickness do notapply to the bentportion of U-tubes. At the bent portion of a U-tube, for R p 2 ? D, neither the major nor minor diameter of the tube shall deviate from nominal by more than 10%.
10.3 Permissible variations from the specified straight length shall be in accordance with Specification A 450/A 450M. 10.4 In the case of U-tubes, the length of the tube legs, as measured from the point of tangency of the bend and the tube leg to the end of the tube leg, shall not be less than specified, but may exceed the specified values by the amount given in Table 4. The difference in lengths of the tube legs shall not be greater than 1 ⁄ 8 in. [3 mm] unless otherwise specified. 10.5 The end of any tube may depart from the square by not more than the amount given in Table 5. 10.6 The leg spacing measured between the points of tangency of the bend to the legs shall not vary from the value (2R-specified tube OD) by more than 1 ⁄ 16 in. [1.5 mm] where R is the centerline bend radius. 10.7 The bent portion of the U-tube shall be substan- tially uniform in curvature and not exceed ± 1 ⁄ 16 in. [±1.5 mm] of the normal centerline radius.ASME SA-557 SA-557M pdf download.