ASME PTB-13-2021 pdf free download.Criteria for Pressure Retaining Metallic Components Using Additive Manufacturing
3 MATERIALS
(a) For the purpose of these criteria, Material is defined as an additively manufactured component meeting the requirements of the ASME material specification.
(b) The Additive Manufacturer shall select a listed wrought ASME material specification from ASME BPVC Section II for the component material. The selected ASME material specification shall be identified in the Additive Manufacturing Specification. In the remainder of this document, the selected material specification is identified as the ASME material specification.
(c) The requirements for chemical composition, grain size (where applicable), hardness, final heat treatment and mechanical properties shall be identical to the requirements of the ASME material specification.
(d) When a material does not meet a wrought material specification in ASME Section II, the Additive Manufacturer may request approval of a new material from ASME in accordance with the requirements of Appendix 5 of ASME BPVC Section II, Part D [1].
(e) All material processing and testing shall meet the requirements of the Additive Manufacturing Specification and these criteria.
Commentary
The material for the AM component is the additively manufactured component in its final heat-treated condition. The Additive Manufacturer shall select a listed wrought ASME material specification from ASME BPVC Section II for the AM component material. The selected ASME material specification shall be identified in the Additive Manufacturing Specification. The AM Committee reviewed data generated by several additive manufacturers and determined that AM component properties are appropriate to meet wrought specifications [2] when the additive manufacturer has achieved control of the AM process through rigorous qualification testing (see Section 8). Specifying the use of wrought material for AM component material follows the same direction used for the recent additions to ASME Code for components manufactured using powder metallurgy/hot isostatic pressing technology. The AM material shall meet the ASME material specification requirements for chemical composition, grain size, hardness, final heat treatment and mechanical properties. When a material for use in an AM build does not meet a wrought material specification in ASME Section II, the Additive Manufacturer may request approval of a new material from ASME in accordance with the requirements of ASME Section II, Part D, Appendix 5 [1]. As additive manufacturing becomes more common, the need will exist for new material with thermal treatments optimized for the powder bed fusion process, and thus, new materials will be needed for Code application.
4 THERMAL TREATMENT
(a) The final heat treatment of the AM material shall be that specified in the ASME material specification.
(b) Additional intermediate thermal treatment is acceptable. Intermediate thermal treatment may include stress relief, hot isostatic pressing or other thermal processing.
(c) When intermediate thermal treatment is performed, ASTM F3301 [3] may be used as guidance.
(d) When hot isostatic pressing is performed, recognized standards such ASTM A988 [4] or ASTM A1080 [5] may be used as guidance.
(e) All material testing shall be performed on material specimens in the final heat-treated condition of the ASME material specification.
Commentary
The AM component is required to have the identical final heat treatment requirements applied to the built component as specified for the ASME material specification. Additional intermediate thermal treatment such as hot isostatic pressing (HIP) is acceptable, but is not required by the criteria. The ASME AM Special Committee reviewed data that compared material properties for material receiving an intermediate HIP thermal treatment to material that had not received a HIP treatment. The data supports applying a HIP thermal treatment to improve the material properties by reducing defects through densification, but is not always necessary to meet the properties of the material specification. Depending upon the material, as- built microstructure, type and size of defect, HIP does not always improve material properties. The data also showed that applying a HIP thermal treatment will not account for a lack of rigorous AM process control prior to starting production builds. The emphasis in these AM criteria is achieving and maintaining process control during the AM builds. The criteria provide guidance for specifying the requirement for HIP and other intermediate thermal treatments in Section 4 when these processes are specified in the AM Specification (Section 2).ASME PTB-13 pdf download.ASME PTB-13-2021 pdf free download
