ASME SA-250 pdf free download
ASME SA-250-SA-250M-2021 pdf free download.Standard Specification for Electric-Resistance-Welded Ferritic Alloy-Steel Boiler and Superheater Tubes.
5.3.2 When grades T1, Tla, TIb, and T2 are cold finished, the tubes may, at the option of the manufacturer, be heat treated after the final cold drawing pass at a temperature of 1200 oF or higher, provided one of the heat treatments specified in
5.3.1 was applied after welding.
6. Chemical Composition
6.1 The steel shall conform to the requirements given in Table 1.
6.2 Product Analysis 6.2.1 An analysis of either one length of fat-olleld stock or one tube shall be made on each heat. The chemical composition thus determined shall conform to the requirements given in Table 1. 6.2.2 If the original test for product analysis fails, retests of two additional lengths of fat-rolled stock or tubes shall be made. Both retests for the elements in question shall meet the requirements of the specification; otherwise all remaining material in the heat or lot (See 8.1) shall be rejected or, at the option of the producer, each length of fat. rolled stock or tube may be individually tested for acceptance. Lengths of fat- rolled stock or tubes that do not meet the requirements of the specification shall be rejected.
7. Mechanical Requirements
7.1 Tensile Requirements
7.1.1 The material shall conform to the requirements as to tensile properties given in Table 2.
7.1.2 Table 3 gives the computed minimum elongation values for each V/3z-in. [0.8-mm] decrease in wall thickness. Where the wall thickness lies between two values given in Table 3, the minimum elongation value shall be determined by the following equation:
where: E = elongation in 2 in. [50 mm] %, and ↑= actual thickness of specimen, in.[mm].
7.2 Hardness Requirements- The tubes shall have a hard- ness not exceeding the values given in Table 4.
7.3 Mechanical Tests Required 7.3.1 Tension Test- One tension test shall be made on a specimen for lots of not more than 50 tubes. Tension tests shall be made on specimens from two tubes for lots of more than 50 tubes (See 8.2). 7.3.2 Flattening Test- One fattening test shall be made on specimens from each end of one finished tube, not the one used for the flange test, from each lot (See 8.1). 7.3.3 Flange Test- One flange test shall be made on speci- mens from each end of one finished tube, not the one used for the fattening test, from each lot (See 8.1). 7.3.4 Reverse Flattening Test- One reverse fattening test shall be made on a specimen from each 1500 ft [450 m] of finished tubing- 7.3.5 Hardness Tesl- Brinell and Rockwell hardness tests shall be made on specimens from two tubes from each lot (See 8.2). 7.3.6 Hydrostatic or Nondestructive Eletric Tests- Each tube shall be subjected to either the hydrostatic or the nonde- structive electric test. The purchaser may specify which is to be used. 8. Sampling 8.1 For fattening and flange requirements, the term lot applies to all tubes prior to cutting of the same specified outside diameter and specified wall thickness that are produced from the same heat of steel. When final heat treatment is in a batch-type furmace, a lot shall include only those tubes of the same size and from the same heat that are heat treated in the same furnace charge. ASME SA-250 pdf download.
