1. Scope

10 1.1. This specification covers additive manufacturing of parts via full-melt laser beam
11 powder bed fusion (PBF-LB) processing of maraging steel alloys. Parts made using this
12 processing method are typically used in applications that requiremechanical properties
13 similar to wrought products, either as fabricated or heat treated. Products built to this
14 specification may require additional post-processing in the form of machining, polishing,
15 etc., to meet necessary surface finish and dimensional requirements.
16 1.2. Maraging steel (MS) is a class of precipitation hardened steel, where aging heat
17 treatment is used to form precipitates and, consequently, achieve significantly increased
18 hardness and strength. This specification focuses specifically on 300 grade maraging
19 steel, which corresponds to UNS K93120. MS grade 300 has higher concentrations of
20 cobalt and titanium than lower grades.
21 1.3. This specification is intended for the use of purchasers or producers, or both, of
22 additively manufactured maraging steel parts for defining the requirements and ensuring
23 part properties.
24 1.4. Users are advised to use this specification as a basis for obtaining parts that will meet the
25 minimum acceptance requirements established and revised by consensus of committee
26 members.
27 1.5. User requirements considered more stringent may be met by the addition to the purchase
28 order of one or more supplementary requirements, which include, but are not limited to,
29 those listed in Supplementary Requirements in Sections 27-29.
30 1.6. The values stated in SI units are to be regarded as standard. All units of measure
31 included in this guide are accepted for use with the SI

Keywords

additive manufacturing; powder bed fusion; PBF-LB; maraging steel

Rationale

This new work item proposal addresses two of the AMSC roadmap gaps, FMP1: material properties, and FMP4, design allowables. Current standards on materials from ASTM and ISO-ASTM focus on materials of interest to the aerospace and medical industries, for the most part. This proposed work item on maraging steel has relevance to many other precision engineering industries, including automotive, marine and offshore, machine tools, sports, and others, in addition to aerospace. Maraging steel has high strength and high toughness without losing ductility, good weldability, and dimensional stability, making it suitable for a wide variety of high strength applications. This specification is intended for the use of purchasers or producers, or both, of additively manufactured maraging steel, series 300 (UNS K93120), components for defining the requirements and ensuring component properties. It is being balloted concurrently due to the exigency of need and the maturity of the draft (having been through a series of information gathering exercises, including a period of pre-ballot review, which generated significant feedback; the lion’s share of which has been incorporated herein).

The title and scope are in draft form and are under development within this ASTM Committee.