A S M E

P T B - 1 3 - 2 0 2 1

Crite ria fo r Pre ssur e Re taining Me tallic Compone nts Using

Ad ditive Manu factu ring

ASME PTB-13-2021

CRITERIA FOR PRESSURE RETAINING METALLIC COMPONENTS USING ADDITIVE MANUFACTURING

Prepared by:

The ASME BPTCS/BNCS Special Committee on Use of Additive Manufacturing for Pressure Retaining Equipment

Date of Issuance: May 31, 2021

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TABLE OF CONTENTS

Table of Contents iii

Foreword iv

Executive Summary v

1. SCOPE 1

2. ADDITIVE MANUFACTURING SPECIFICATION 3

3. MATERIALS 5

4. THERMAL TREATMENT 6

5. POWDER REQUIREMENTS 7

6. ADDITIVE MANUFACTURING DESIGN REQUIREMENTS 9

7. ADDITIVE MANUFACTURING PROCEDURE 10

8. ADDITIVE MANUFACTURING PROCEDURE QUALIFICATION 13

9. QUALIFICATION TESTING OF ADDITIVE MANUFACTURED COMPONENTS 17

10. PRODUCTION BUILD CYCLES 22

11. CHEMICAL COMPOSITION TESTING 26

12. MECHANICAL PROPERTY TESTING 27

13. METALLOGRAPHIC EVALUATION 29

14. IN-PROCESS MONITORING 30

15. QUALITY PROGRAM 31

16. RECORDS 32

17. DEFINITIONS 33

    References 35

    LIST OF TABLES

    Table 7-1: Process Variables for Laser and Electron Beam Powder Bed Fusion Processes 11

    Table 7-2: Procedure Qualification Criteria 12

    Table 8-1: Locations for Material Qualification Specimens for Procedure Qualification (PQ) Builds 14 Table 8-2: Required Types of Material Qualification Test for Each Location 15

    Table 9-1: Prototype Testing Requirements 17

    Table 9-2: Locations for Material Qualification Specimens for Component Qualification (CQ) Build17 Table 9-3: Required Types of Material Qualification Specimens for Each Location 18

    Table 9-4: Fatigue Test Acceptance Criteria 20

    Table 10-1: Production Testing Requirements 22

    Table 10-2: Full Production Witness Sample Testing Criteria 23

    Table 10-3: Reduced Production Witness Sample Testing Criteria 24

    LIST OF FIGURES

    Figure 8-1: Material Qualification Specimens for Additive Manufacturing Procedure Qualification .13 Figure 10-1: Full Production Witness Sample Testing 23

    Figure 10-2: Reduced Production Witness Sample Testing 24

    FOREWORD

    This report provides specific criteria completed by the ASME Board on Pressure Technology Codes and Standards (BPTCS)/Board on Nuclear Codes and Standard (BNCS) Special Committee on Use of Additive Manufacturing. These first criteria address the Additive Manufacturing (AM) Powder Bed Fusion Process.

    
    

    Acknowledgements

    The following members of the BPTCS/BNCS Special Committee on Use of Additive Manufacturing for Pressure Retaining Equipment are acknowledged for their support for the technical preparation of this criteria document: George Rawls-Chair, Ryan Spotts-Vice Chair, Annemarie Appleton. Clint Armstrong, Richard Barnes, Robert Bianco, Allyson Byk, Michael Carney, Jessica Coughlin, David Gandy, Giancarlo Gobbi, David Hardacre, Xiaoming He, Wolfgang Hoffelner, Keith Hottle, Thomas Lippucci, Mike McMurtrey, David Poole, Richard Porco, Mahendra Rana, Colleen Rodrigues, David Rudland, Christian Sanna, Eugene Shapiro, Walter Sperko, Matthew Standley, Hongqing Xu, Wei Zhang, Jason Lambin, David Gross and Thomas Vogan.

    The following subject matter experts are acknowledged for their thorough peer review of the document: For the BPTCS: P. Lynn Sturgill, Steven Roberts, and Daniel Peters. For the BNCS: Richard Wright, Keiji Matsunaga, Michael Doersam, and Ned A. Finney Jr.

    Finally, the efforts of Gerry Eisenberg of ASME and Dan Andrei of the STLLC are acknowledged for their management of the peer review group, review of the manuscript prior to publication, editing and document preparation resulting in the publication of this document.

    
    

    Established in 1880, ASME is a professional not-for-profit organization with more than 100,000 members promoting the art, science, and practice of mechanical and multidisciplinary engineering and allied sciences. ASME develops codes and standards that enhance public safety, and ASME provides lifelong learning and technical exchange opportunities benefiting the engineering and technology community. Visit www.asme.org for more information.

    STLLC is a not-for-profit limited liability company, with ASME as the sole member, formed in 2004 to carry out work related to new and developing technologies. STLLC’s mission includes meeting the needs of industry and government by providing new standards-related products and services, which advance the application of emerging and newly commercialized science and technology and provides the research and technology development needed to establish and maintain the technical relevance of codes and standards. Visit https://asmestllc.org/ for more information.

    EXECUTIVE SUMMARY

    Recognizing a need to keep pace with rapid advancements in AM technology and AM’s growing acceptance in industry the ASME BPTCS appointed a project team to evaluate the additive manufacturing technology as it applies to the construction of pressure equipment in 2015.

    The first meeting of the ASME Project Team on Evaluation of Additive Manufacturing for Pressure Retaining Equipment was held in December 2015. The project team drafted and issued a gap analysis to the BPTCS in June 2016. The ASME NCS was also evaluating implementation of AM technology and was part of the membership of the ASME Project Team on AM. Following thorough review and discussion of the gap analysis, a recommendation was made to BPTCS to form a Special Committee on Use of Additive Manufacturing for Pressure Retaining Equipment. The formation of the committee was approved as a joint committee reporting to both the BPTCS and the BNCS.

    The first meeting of the BPTCS/BNCS Special Committee on Use of Additive Manufacturing for Pressure Retaining Equipment was held in August 2017. The Special Committee began work on background information needed to support a technical baseline for the development of criteria for the AM Powder Bed Fusion Process. This report provides the specific criteria completed by the BPTCS/BNCS Special Committee on Use of Additive Manufacturing. These first criteria address the AM Powder Bed Fusion Process.

    This additive manufacturing document provides criteria followed by commentary for the following areas:

    • Scope

    • Additive Manufacturing Specification

    • Materials

    • Thermal Treatment

    • Powder Requirements

    • Additive Manufacturing Design Requirements

    • Additive Manufacturing Procedure

    • Additive Manufacturing Procedure Qualification

    • Qualification Testing of Additive Manufactured Components

    • Production Build Cycles

    • Chemical Composition Testing

    • Mechanical Property Testing

    • Metallographic Evaluation

    • In-Process Monitoring

    • Quality Program

    • Records

    • Definitions

    • Referenced Standards

Description of the Powder Bed Fusion Additive Manufacturing Process

The build process begins by placing a baseplate into the machine. The printed component is constructed on this plate. The plate serves as a method of securing the component during printing, a method of preventing warping of the component, and a path for the removal of heat during the build process. The build chamber is sealed and is either purged and backfilled with an inert gas such as argon when using a laser energy source, or is left with a vacuum when using an electron-beam energy source. A thin layer of powder on the order of 100µm is deposited. Then, the energy source selectively melts specified areas of the powder in a prescribed geometry conforming to the component being manufactured.

At the completion of the layer, the fabricated portion of the component and the build plate are lowered, and another layer of powder is deposited. This process is repeated through the build until the full component height has been accomplished. At the end of the build, the component and build plate are extracted from the machine for thermal treatment and post processing.

1 SCOPE

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

   
   

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

   
   

3. 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.

   
   

4. The maximum design temperature shall be 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 in ASME Section II, Part D [1].

   
   

5. 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].