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ASME B16.49-2017 pdf download

1 SCOPE AND DEFINITIONS 1.1 General This Standard covers design, material, manufacturing, testing, marking, and inspection requirements for factory- made pipeline bends of carbon steel materials having controlled chemistry and mechanical properties, produced by the induction bending process, with or without tangents. This Standard covers induction bends for transportation and distribution piping applica- tions (e.g., ASME B31.4 and ASME B31.8). Process and power piping have differing requirements and materials that may not be appropriate for the restrictions and exam- inations described herein and, therefore, are not included in this Standard. 1.2 Manufacturing Process This process utilizes induction heating to heat a narrow band 360 deg around a pipe or cylinder at the point of bending as the pipe or cylinder is being pushed through the inductor coil at a constant velocity. After the material passes through the coil, it may be cooled by forced air or water spray, or it may be allowed to cool in still air. Bends in any producible wall thickness and diameter are covered. Induction bends covered by this Standard may be produced from seamless pipe, welded pipe, or cylinders. 1.3 Fabricated Bends Larger angle bends obtained by girth welding two or more smaller angle bends together are considered pipe fabrications and as such, are not within the scope of this Standard. 1.4 Standard Units This Standard states values in both SI (Metric) and U.S. Customary units. These systems of units are to be regarded separately as standard. Within the text, the U.S. Customary units are shown in parentheses. The values stated in each system are not exact equivalents; therefore, it is required that each system of units be used independently of the other. Combining values from the two systems constitutes nonconformance with the Standard. 1.5 References Standards and specifications adopted by reference in this Standard are shown in Mandatory Appendix I. It is not practical to identify the specific edition of each stan- dard and specification in the individual references. Instead, the specific edition reference is identified in Mandatory Appendix I. A product made in conformance with a prior edition of reference standards and in all other respects conforming to this Standard will be considered to be in compliance. 1.6 Codes and Regulations A bend used under the jurisdiction of a referencing code or governmental regulation is subject to any limitation of that code or regulation. This includes any maximum temperature limitation or rule governing the use of a material at low temperature. 1.7 Service Conditions Criteria for selection of bend material for a particular fluid service are not within the scope of this Standard. 1.8 Convention For determining conformance with this Standard, the convention for fixing significant digits where limits (maximum and minimum values) are specified shall be as defined in ASTM E29. This requires that an observed or calculated value be rounded off to the nearest unit in the last right-hand digit used for expressing the limit. Decimal values and tolerances do not imply a particular method of measurement. 1.9 Quality Systems Requirements relating to the manufacturers’ quality system programs are described in Nonmandatory Appendix A. 1.10 Glossary bend qualification procedure: a document that specifies the properties of the starting pipe; the equipment to be used; the bending parameters; the qualification bend test results; and the postbend, heat-treat equipment, and cycle used for the manufacture of the bends. If nondes- tructive testing of the bend is required, procedures that have not been approved previously shall be submitted.
8.3 Hardness Testing Hardness tests shall be performed in accordance with ASTM A370 on the bend as required in para. 11.1.4. To verify uniformity in the bending process, all production bends shall be tested for hardness in the same locations as the qualification bend. The corresponding areas shall have average hardness readings not varying by more than 30 Brinell hardness, or equivalent, from the average value measured in the same location of the qualification bend, with no average equating to a tensile strength less than that required in Table 1 for the material grade marked on the bend. Use an average of at least three readings for each location tested. The type of portable hardness tester used on production bends shall be the same as used on the qualification bend. All testing shall be conducted in the final heat-treated condi- tion. No hardness measurement shall exceed the maximum specified in Table 1. 9 HEAT TREATMENT 9.1 Type Unless otherwise specified by the purchaser, each bend shall be heat-treated after bending (except as permitted in para. SR15.1) by one or more of the following methods: (a) Stress Relieve or Temper. Uniformly, heat between 480°C (900°F) and 675°C (1,250°F) and hold at tempera- ture for at least 30 min per 25 mm (1 in.) of thickness at temperature, but no less than 30 min. (b) Normalize. Heat above the transformation tempera- ture range and hold at temperature for a minimum of 20 min per 25 mm (1 in.) of thickness, but not less than 20 min, and allow to cool in still air.

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