ASME PTB-13:2021 pdf free download

ASME PTB-13:2021 pdf free download.Criteria for Pressure Retaining Metallic Components Using
Additive Manufacturing.
6.1 Commentary
The design requirements for AM components follow the requirements in the applicable ASME Construction Code or Standard. The criteria require that each component has a design report. ASME BPV Code Section Ill and Section VIII. Division 2 have requirements for the content of a design report and can be applied for nuclear and non-nuclear applications, respectively. When the governing Construction Code or Standard applicable to the AM component does not have specific requirements for a design report thc requirement in Section VIII. Division 2 are recommended for design. The Section VIII. Division 2 rules in Part 4 and Part 5 are acceptable ftr design as applicable. Since many of the AM componems will have a significantly complex geometiy. the rules of Section VIII Division 2, Part 5 are the most applicable for AM design for non-nuclear applications. The detailed stress analysis requirement in Section VIII. Division 2. Part 5 also allows for identification of the areas of high stress and fatigue critical areas in a component necessary for use in determining the location of required test specimens specified in Section 9 and direct NDE.
The AM build process requires that support structures be integrated into the build to provide support for overhanging sections of the component that occur abose the build plate. The integral supports also serve to restrain the geometry against deflections caused by residual stresses that are generated during the build. These supports can be either sacrificial or permanent. Component surfaces interfacing with sacrificial supports need to be fully accessible for removal of supports and for liquid penctrant examination. The examination of these locations ensure that an unevaluated stress riser docs not affect the structural integrity of the component. The effect of possible stress risers from any support that will not be removed tillowing the AM build is required to be evaluated during the component stress analysis. Any material in a permanent support that is credited as load hearing in the stress analysis shall meet all relevant AM cntcrla provided in this report.
The surfaces of an AM component can be constructed with machine parameters to optimize dimensional tolerances and surface finish. These surfaces are defined as cosmetic material. Specifically. cosmetic material is material produced by process parameters that are not represented by qualification or witness specimen test results. When performing a stress analysis for an AM component. cosmetic material is not credited as load bearing material in the stress analysis. The cosmetic layer is addressed in the same manner as for material added for corrosion or mechanical allowance in the ASME construction code.