ASME B31J:2017 pdf free download – Stress Intensification Factors (i-Factors), Flexibility Factors (k-Factors), and Their Determination for Metallic Piping Components
The test specimen may be fabricated from a lower- strength carbon steel, such as ASTM A106 Grade B pipe or ASTM A234 Grade WPB fittings, or equivalent plates and forgings, corresponding to the “UTS < 80 ksi” curve in ASME Boiler and Pressure Vessel Code, Section VIII, Division 2, Mandatory Appendix 3-F(a). For other materials, the material constant, C, shall be modified or derived as described in para. A-3.1 ifneeded. The fabrication, welding, and examination ofthe tested componentshallbethesameasthatexpectedto beusedin service. Weld contours and procedures should also be representative of those intended to be used in practice. Weld locations where fatigue cracks are likelyto originate should be inspected for undercut, welding starts and stops, or other anomalies that may affect fatigue life. Where welding starts and stops, undercuts, or other irregularities are visible at potential crack sites, these imperfections should be documented. All weld profiles, sizes, repairs, and/or photographs should be recorded and included in the Test Report. Where leakage is anticipated in or adjacent to a weld, thedimensionsoftheweldinthatareashouldberecorded carefully and variations in the weld contours noted in the Test Report. After the test is completed, the inside weld profile at the failure location should be described in the Test Report with photographs ifpossible and any anoma- lies noted.
(a) The test specimen shall be mounted in the test assembly to develop a load-deflection diagram using the same procedure that will be used during the cyclic loading portion of the fatigue test. To develop the load-deflection diagram, displacements shall be applied in positive steps in the linear range to obtain a load-dis- placement diagram similar to that shown in Figure A-1.3- 1. Atleastfive points shall be recorded in the linearregion of the diagram. A point can be considered in the linear range if after the displacement is applied the load does not change for a period of at least 3 minutes.
(b) The initial loading sequence described in para. (a) shall be stopped when the load-displacement plot is no longer linear or when a sufficient linear portion of the diagram has been produced. To accommodate this requirement, the loading sequence may require one or two steps into the nonlinear range. If the cycle range is known to be well within the linear portion of the load-deflection plot range produced in para. (a), deflec- tions in the nonlinear portion of the load-deflection diagram are not required. Several cycles within the linear range may be applied to remove fabrication and installation residual effects before the load-displacement plot is produced.
(c) Ifthereis anexpectationthatdeflectionintheoppo- site direction will produce a different load-displacement diagram, the specimen should be unloaded following the same recordingsequence used duringthe loadingsteps in paras. (a) and (b), and displacement applied in the oppo- site direction to approximately the same displacement magnitude used in the positive displacement loading sequence in para. (b). Ifthe slope ofthe reverse-direction load-displacement diagram is sufficiently different from the slope of the positive-direction load-displacement diagram, the smaller value of the slope shall be used when determining F e in eq. (A-1).