Verification Build Design and Development for Additively Manufactured 4340 Steel

Abstract

Designing an appropriate verification build layout is critical in substantiating process parameters developed for a particular material in a particular additive manufacturing machine. Two different verification builds were executed with 4340 steel process parameters developed by the U.S. Army Combat Capabilities Development Command (DEVCOM) Armaments Center (AC), Picatinny Arsenal, NJ, for laser powder bed fusion (L-PBF) on an EOS M290. The two builds had different processing conditions, with the second build improving on the first. Both verification builds included XY and Z oriented tensile coupons in five locations (four corners and the center of the build plate). The specimens were then machined, heat treated, and characterized. The Z tensile properties were equivalent to the XY orientation tensile specimens in both verification builds. All but one specimen from the first verification build and all the specimens in the second verification build met 4340 wrought minimum requirements. The same processing parameters and metal powder verified in the second build were utilized to manufacture parts, but the parts failed to build to completion. The verification build, which had met the minimum mechanical requirements, failed to capture all the effects of having tightly packed parts on the build plate and resulted in build failures. The parts were eventually built by reducing the number of parts on the build plate, which improved the gas flow. As parts become larger and closer together, the nuances of gas flow in L-PBF of 4340 will need to be better understood and incorporated into process design that accurately predicts material quality.

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Document Details

Document Type
Technical Report
Publication Date
May 11, 2022
Accession Number
AD1168466

Entities

People

  • Eli Golden
  • Elias Jelis
  • Matthew Clemente
  • Matthew Feurer
  • Michael Hespos
  • Shana Groeschler

Organizations

  • United States Army Combat Capabilities Development Command

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Additive Manufacturing
  • Chemistry
  • Gas Flow
  • Heat Treatment
  • Manufacturing
  • Materials
  • Materials Engineering
  • Materials Processing
  • Mechanical Properties
  • Particle Size
  • Particles
  • Powder Metals
  • Powders
  • Selective Laser Sintering
  • Standards
  • Tensile Properties
  • Tensile Strength

Readers

  • Cybersecurity.
  • Materials Science and Engineering.
  • Systems Analysis and Design

Technology Areas

  • Directed Energy