ASME B31J-2008 pdf free download.Standard Test Method for Determining Stress Intensification Factors (i-Factors) for Metallic Piping Components.
A test report shall be prepared and certified to meet the requirements of this Standard by a Registered Proicssional Engineer, or person of equivalent expertise, as defined by national practice’, competent in the design and analysis of pressure piping systems. The test report shall be complete and written to facilitate an independent review. The report shall cOntain
(a) description of the tested specimens.
(b) nominal pipe and piping component size and dimensions and actual cross-sectional dimensions of importance in interpreting the test results.
(C) description and photograph(s) or sketch(es) of the test equipment. including positioning of the test spedmens in the machine.
(d) calibration of the test equipment. This information may be provided by reference.
(e) certified material test reports for the tested component, including mill-test value of yield and ultimate strength.
(f) component and component-to-pipe weld examinations where they are required by the construction Code. with certification of Code compliance of the welds. A copy of the Welding Procedure Specification (WI’S) and the Welding Operator Performance Qualification (Wl’Q) of the welding operator who welded the components. along with a narrative of the visual examination of th welds used in the test pieces, shall also be Included, if possible. good quality photographs of all or a portion of the wcldments should be included in the report.
() assembly procedure used for joints.
(h) loading and unloading load-displacement points and line, in accordance with para. 3_I.
(1) values of material constant, C, section modulus, Z, number of cycles to leakage, N, length to leak point, L, and imposed displacement for each test.
(j) derivation of the force. Fe, moment, M, and the stress intensification factor, i, for each test.
(k) description and photograph(s) or sketch(es) of the leak location.
(I) justification for geometric similarity, if any, in accordance with para. 5.2.
The Codes for Pressure Piping (for example, ASME 1331.1 and 1331.3; ASME I3PVC, Section III, Class 2/3) use stress intensification factors (i-factors) for various piping components and joints as a measure of their fatigue perfornunce relative to girth butt welds, Occasionalh a need arises to establish i-Iactors for components not included in the Codes, such as a branch connection in an elbow or some proprietary piping corn. ponent. This Standard provides a set of requirements that will ensure that newly developed i-factors will be consistent with the existing s-factors.
(a) Papers by Markl 121, Markl and George 131. and Markl 141 provided the basis for most of the i-factors in the Codes, Key aspects of the testing and interpretation of test results are as follows:
(1) a preliminary load-deflection plot was developed (see Fig. 3.3)
2) cyclic bending tests were run with controlled displacements
3) failure was defined as a through-wall crack
4) the i-factor was calculated by eq. (3)
5) Mark 151 discusses “Allowable Stress Range” and, in Appendices 1 and 2 of his paper, describes rules that were eventually incorporated in ANSI B31.1-1955. These rules are essentially unchanged. This paper discusses the following three concepts that are fund,imental to the use and interpretation of i-factors as a control of fatigue failure:
(1) the i-factors are dependent upon dimensions and are independent of the material
(2) as a consequence of (1). i-factors developed by Markl using ASTM A 106 Grade 13 material are presumed to be applicable to components made of any of the metallic materials listed in the Piping Codes
3) the Code stress limits are proportional to the fatigue strength of materials used in the components.