ASME B16.49:2017 pdf free download – Factory-Made, Wrought Steel, Buttwelding Induction Bends for Transportation and Distribution Systems
8.1 Tensile Properties
The tensileproperties shall be determinedforthequali- ficationbendinaccordancewithASTMA370.Theyield-to- tensile ratio shall not exceed 0.90, except for Grade P483 (X483) and higher, for which the ratio shall not exceed 0.93. When the strength of the bend does not meet the ordered strength, the manufacturer may provide, with purchaser approval, bends of comparable strength to the design pipe. The thickness of the bend shall be at least equal to the specified design pipe thickness multi- plied by the ratio ofthe specified minimum yield strength ofthe pipe and the minimum tested yield strength ofthe bend. For bends from welded pipe of NPS 8 (DN 200) or larger, a transverse weld tensile testin the final heat-treat condition shall be conducted to determine the ultimate tensile strength. See para. 11.1.1 for number, location, and orientation of test samples required.
8.2 Fracture Toughness
Properties Notch toughness properties ofthe bend material in the final heat-treated condition shall be determined on the qualification bend in all locations specified in Figure 2 or Figure 3 by a set of three transverse, full-size, Charpy V-notch specimens, with or without tapering 3 the ends, in accordance with ASTM A370. When the mate- rial wall thickness does notpermitmachiningfull-size (10 mm× 10 mm) specimens,thelargestsizepossibleofeither 2 ∕ 3 size or 1 ∕ 2 size shall be substituted. All dimensions other than thickness are the same for full-size specimens. Specimens shall be taken with the axis transverse to the longitudinal axis ofthe bend. Ifmaterial wall thickness does not allow at least a 1 ∕ 2 -size Charpy specimen, no impact testing is required. Specimens shall be tested at −10°C (+14°F) or lower, unless otherwise specified by the purchaser (see para. SR15.4), and shall achieve an average shear area for all specimens of at least 50%, with no one specimen less than40%. In addition, all speci- mensshallexhibitaminimumabsorbedenergyvalueof27 J (20 ft-lbf) for Grade P386 (X386) and lower, and a minimum of 54 J (40 ft-lbf) for grades higher than P386 (X386). Weld metal shall meet an absorbed energy value of 27 J (20 ft-lbf) minimum for all grades. If using reduced specimens, the impact values may be reduced in accordance with the correction ratios in ASTM A370. See para. 11.1.2 for location of testing samples required.
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 forhardness in the same locations as thequalificationbend. Thecorrespondingareas shallhave 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.