“Metal 3D printing” is an umbrella term that is used to describe several manufacturing processes for additive manufacturing of metal parts. The material is processed in a layer-by-layer manner, through sintering, welding, or melting. Two common metal 3D printing processes are Selective Laser Melting (SLM) and Direct Metal Laser Sintering (DMLS). Both of these use powder-bed fusion technology. While metal 3D printing can produce parts from a large range of metals and metal alloys, the best materials for metal 3D printing are stainless steel, tool steels, titanium, and Inconel (nickel-based) alloys.
This article will define what metal 3D printing is, how it works, discuss the four best materials for metal 3D printing, and what materials work best in different applications.
1. Stainless Steel
Stainless steel is widely known for its ability to withstand corrosion, high strength, and excellent aesthetic appearance. Parts printed with stainless steel can have the same or even greater strength than parts created using traditional manufacturing methods. The strength, hardness, and other properties of 3D-printed stainless steel depend mainly on the specific technology used to print the part.
Stainless steel-printed parts have found application in many industries, including aerospace, automotive, military hardware, and medical. Compared to other metal 3D printing materials, stainless steel parts can be made with the smoothest surfaces because of the addition of chromium.
Stainless steel powder used for 3D printing comes in a variety of grades and alloys, including 316L, 304L, 630, 410, 420, 254, 17-4 PH, 15-5PH, PH1, and GP1. Of these, 316L is the most commonly used grade in metal 3D printing. It has a composition of 66-70% iron enhanced with 16-18% chromium, 11-14% nickel, 2-3% molybdenum, and less than 0.03% carbon. This 3D printing material is known for its ductility and good corrosion resistance.
2. Tool Steels
Tool steels are a family of iron-based alloys containing relatively high levels of carbon, which form carbides with other alloying elements, including tungsten, chromium, vanadium, and molybdenum. Tool steels offer an excellent combination of high-temperature strength, hardness, and wear resistance. These steels are commonly applied in the production of molds, stamps, and cutting tools in multiple industries. The tools are used to manufacture geometries that are used in other product manufacturing processes, including extrusion, cutting, casting, injection molding, stamping, and component assembly. The following tool steel options are available for metal 3D printing—D2, M2, H13, H11, MS1, and 1.2709.
3. Titanium
Titanium is the most-used metal in the additive manufacturing industry. It is widely employed in the medical, aerospace, automotive, and electronic industries, among others. Titanium and its alloys have high mechanical strength. They also offer better corrosion resistance than stainless steel.
The following titanium material options are available for metal 3D printing—Ti-6Al-4V, Beta 21S, Cp-Ti (commercially pure titanium), and TA15.
4. Inconel 625
Inconel 625 is a nickel-based superalloy that offers high strength and can retain its strength over a wide temperature range. Due to its excellent corrosion and oxidation resistance, it is considered ideal for corrosive environments. Inconel 625 finds application in the marine, energy, and chemical processing industries. Some applications of Inconel 625 include boat propellers and heat exchanger casings.
