ASME PTB-13:2021 pdf free download – Criteria for Pressure Retaining Metallic Components Using Additive Manufacturing
The criteria provided in this PressureTechnology Book (PTB) address the construction of pressure retainingcomponents by means of the AM Powder Bed Fusion process(PBF) using both Laser and Electron Beamenergy sources.
When additively manufacturing components, these criteria are intended to be used with an existing ASMEConstruction Code or Standard. This PTB provides criteria to address the additional information necessaryto supplement construction code requirements for materials, design, fabrication, examination, inspection,testing and quality control. These supplementary criteria are essential for any proposed standard or codeaction for the construction of metallic pressure retaining components using powder bed fusion.
The AM process is not intended for the manufacture of pressure components when traditionalmanufacturing methods will provide a cost and efficiency advantage. AM has advantage in the fabricationof complex components and applications with high-cost materials. AM provides a cost advantage whensubtractive manufacturing processes result in large amounts of material waste. AM also provides scheduleadvantages and improved lead time compared to current forging and casting methods. A market for AM isdeveloping for replacement components in the nuclear industry where the plant operating basis requiresspecific replacement parts. AM provides a manufacturing method to fabricate components to the designcode of record when the original components are no longer available. These initial drivers for AM willrequire the installation of AM components into both existing systems and new construction.The criteriaallow hybrid construction incorporating AM components joined (welded or brazed) to non-AMcomponents.
The ASME AM Special Committee did not investigate data for AM components operating in the materialcreep regime.Creep data were discussed but sufficient material property data was not available to acceptAM components operating at elevated temperature in the scope of the current AM criteria.The maximumdesign temperature is limited to at least 50F (25°C) colder than the temperature where time-dependentmaterial properties begin to govern for the equivalent wrought ASME material specification, as indicatedby the T-Notes in ASME Section II, Part D[1].
The current criteria limit the materials that can be used for the AM Powder bed fusion process to austeniticstainless steels and nonferrous alloys. Current toughness requirements in ASME Codes allow manyexemptions to toughness testing that are experienced based. The restriction on the materials addressesconcerns with the lack of service experience with additively manufactured components by limitingmaterials to alloys that do not have a marked ductile-brittle transition behavior.
The material for the AM component is the additively manufactured component in its final heat-treatedcondition. The Additive Manufacturer shall select a listed wrought ASME material specification fromASME BPVC Section Il for the AM component material.The selected ASME material specification shallbe identified in the Additive Manufacturing Specification.The AM Committee reviewed data generatedby several additive manufacturers and determined that AM component properties are appropriate to meetwrought specifications [2] when the additive manufacturer has achieved control of the AM process throughrigorous qualification testing (see Section 8). Specifying the use of wrought material for AM componentmaterial follows the same direction used for the recent additions to ASME Code for componentsmanufactured using powder metallurgy/hot isostatic pressing technology. The AM material shall meet theASME material specification requirements for chemical composition，grain size， hardness,final heattreatment and mechanical properties.When a material for use in an AM build does not meet a wroughtmaterial specification in ASME Section ll, the Additive Manufacturer may request approval of a newmaterial from ASME in accordance with the requirements of ASME Section ll, Part D, Appendix 5 [1].Asadditive manufacturing becomes more common，the need will exist for new material with thermaltreatments optimized for the powder bed fusion process, and thus, new materials will be needed for Codeapplication.