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ASME - PTB-13

Criteria for Pressure Retaining Metallic Components Using Additive Manufacturing

active, Most Current
Organization: ASME
Publication Date: 31 May 2021
Status: active
Page Count: 44
scope:

(a) These criteria address the construction of pressure retaining component using the AM Powder Bed Fusion process using both Laser and Electron Beam energy sources.

(b) Additively Manufactured components shall meet the requirements of the applicable ASME Construction Code or Standard in addition to these criteria.

(c) Hybrid construction incorporating AM components joined (welded or brazed) to non-AM components is acceptable. Additive manufactured components joined to other AM components or non-AM components shall follow the requirements of the applicable ASME Construction Code or Standard.

(d) The maximum design temperature shall be at least 50°F (25°C) colder than the temperature where timedependent material properties begin to govern for the equivalent wrought ASME material specification, as indicated in ASME Section II, Part D [1].

(e) The materials allowed for use in powder bed fusion under these criteria include:

(1) austenitic stainless-steel alloys; and

(2) nonferrous alloys

Commentary

The criteria provided in this Pressure Technology Book (PTB) address the construction of pressure retaining components by means of the AM Powder Bed Fusion process (PBF) using both Laser and Electron Beam energy sources.

When additively manufacturing components, these criteria are intended to be used with an existing ASME Construction Code or Standard. This PTB provides criteria to address the additional information necessary to supplement construction code requirements for materials, design, fabrication, examination, inspection, testing and quality control. These supplementary criteria are essential for any proposed standard or code action 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 traditional manufacturing methods will provide a cost and efficiency advantage. AM has advantage in the fabrication of complex components and applications with high-cost materials. AM provides a cost advantage when subtractive manufacturing processes result in large amounts of material waste. AM also provides schedule advantages and improved lead time compared to current forging and casting methods. A market for AM is developing for replacement components in the nuclear industry where the plant operating basis requires specific replacement parts. AM provides a manufacturing method to fabricate components to the design code of record when the original components are no longer available. These initial drivers for AM will require the installation of AM components into both existing systems and new construction. The criteria allow hybrid construction incorporating AM components joined (welded or brazed) to non-AM components.

The ASME AM Special Committee did not investigate data for AM components operating in the material creep regime. Creep data were discussed but sufficient material property data was not available to accept AM components operating at elevated temperature in the scope of the current AM criteria. The maximum design temperature is limited to at least 50°F (25°C) colder than the temperature where time-dependent material properties begin to govern for the equivalent wrought ASME material specification, as indicated by 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 austenitic stainless steels and nonferrous alloys. Current toughness requirements in ASME Codes allow many exemptions to toughness testing that are experienced based. The restriction on the materials addresses concerns with the lack of service experience with additively manufactured components by limiting materials to alloys that do not have a marked ductile-brittle transition behavior.

Document History

PTB-13
May 31, 2021
Criteria for Pressure Retaining Metallic Components Using Additive Manufacturing
(a) These criteria address the construction of pressure retaining component using the AM Powder Bed Fusion process using both Laser and Electron Beam energy sources. (b) Additively Manufactured...

References

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