Additively Manufactured Steels

Steels are the most dominant engineering materials used for structural and sub-structural applications[Ref]. A classification of steels along with their applications is shown below [Ref]. Also, the World Steel Association says that are over 3,500 different grades of steel with unique properties[Ref].

Different grades of steel

Steel has been around since the Iron Age and has become an inevitable material in all walks of life, everyday. Broadly classified [Ref] under the following:

1. Carbon Steels

   It accounts for 90% of total steel production and further categorized into three groups depending on their carbon content.

   1. Low Carbon Steels/Mild Steels - upto 0.3% carbon

   2. Medium Carbon Steels - 0.3-0.6% carbon

   3. High Carbon Steels - more than 0.6% carbon

2. Alloy Steels

   Containing alloying elements like Mn, Si, Ni, Ti, Cu, Cr, Al, etc in varying proportions to gain the steel's required properties.

3. Stainless Steels (SS)

   Between 10-20% Cr, as the main alloying element, SS are valued for high corrosion resistance. Based on their crystal structure, further they are classified into:

   1. Austenitic: Non-magnetic and non-heat-treatable and generally contain 18% Cr, 8% Ni and less than 0.8% C.

   2. Ferritic: These magnetic steels have trace amounts of Ni, 12-17% Cr, less than 0.1% C, along with other alloying elements, like Mo, Al or Ti. They cannot be hardened by heat treatment but can be strengthened by cold working.

   3. Martensitic: These magnetic and heat-treatable steels contain 11-17% Cr, less than 0.4% Ni, and up to 1.2% C.

4. Tool Steels

   With the addition of W, Mo, C and V in varying quantities heat resistance and durability increases.

5. Advanced High-Strength Steels

   Mn, Al, Cr, Ni, Si, C, N, B addition and tramp elements Zn, Cu, H, P, S contributing differently to the stability of the iron-rich solutions (liquid, ferrite, austenite (γ), and epsilon (ε)) and the second-phase precipitates.[REF]

   1. Dual-phase steels [REF]

   2. Multi-phase steels [REF1, REF2]

   3. Medium-Mn steels [REF]

   4. High-Mn steels [REF]

   5. Twinning-induced plasticity (TWIP) steels [REF]

   6. Transformation-induced plasticity (TRIP) steels [REF]

   7. Nanocrystalline bainitic steels [REF1, REF2, REF3]

   8. Maraging steels [REF]

Depiction of an industry with various steel components

Additive Manufacturing (AM) of Steels is vast [REF]. There has been a significant increase in interest in AM methods for producing demanding machine parts. AM technologies provide prominent capabilities for production the of machine parts using various advanced engineering materials & at the same time have a few crucial limitations.

Additive Manufacturing

• Laser Powder Bed Fusion (LPBF) / Selective Laser Melting (SLM) [REF]

  • Maraging Steels:

    • 18Ni-300 (Maraging 300) REF

  • Stainless Steels:

    • AISI 316L

    • AISI 304L

    • 17-4PH (Precipitation-Hardening Stainless Steel)

    • 15-5PH

  • Tool Steels:

    • H13

    • D2

    • M2

  • High-Speed Steels:

    • T15

  • Low-Alloy Steels:

    • AISI 4140

• Directed Energy Deposition (DED)

  • Maraging Steels:

    • 18Ni-250

    • 18Ni-350

  • Stainless Steels:

    • AISI 316L

    • AISI 304

  • Tool Steels:

    • H13

    • D2

    • A2

  • Chromium-Molybdenum Steels:

    • AISI 4130

  • High-Strength Low-Alloy Steels (HSLA):

    • HY-80

    • HY-100

• Binder Jetting

  • Stainless Steels:

    • AISI 316L

    • 17-4PH

  • Tool Steels:

    • H13

  • Low-Alloy Steels:

    • AISI 4140

  • Soft Magnetic Alloys:

    • Fe-3%Si (Electrical Steel)

• Wire Arc Additive Manufacturing (WAAM):

  • Stainless Steels:

    • AISI 316L

    • AISI 308L

  • Structural Steels:

    • ER70S-6

    • AISI 1018

  • Maraging Steels:

    • 18Ni-250

  • Tool Steels:

    • H13

• Metal Binder Extrusion (Bound Metal Deposition - BMD):

  • Stainless Steels:

    • AISI 316L

    • 17-4PH

  • Tool Steels:

    • H13

    • A2

  • Low-Alloy Steels:

    • AISI 4140

• Electron Beam Melting (EBM):

  • Maraging Steels:

    • 18Ni-300

  • Stainless Steels:

    • AISI 316L

  • Tool Steels:

    • H13