Stainless steel is the most widely printed metal because it prints reliably, costs less than titanium or nickel alloys, and behaves in service the way engineers already expect stainless to behave. It is where most organisations start with metal additive manufacturing and where a great deal of production additive work still sits.
The grades that print
The austenitic grades print readily and give good corrosion resistance and ductility. Precipitation hardening grades print well and can be heat treated to substantially higher strength, which is why they dominate structural printed parts. Martensitic tool steel grades are used for tooling inserts. Duplex and free machining grades are less common in printing than in bar.
Heat treatment is part of the part
As built printed stainless has a fine cellular microstructure and locked in residual stress. Stress relief on the plate is standard. Solution treatment and ageing on precipitation hardening grades produce the properties that make them worth choosing. Which treatment applies changes strength substantially, so the heat treatment condition belongs on the drawing beside the alloy.
Where printed stainless earns its place
Conformal cooling inserts for injection moulds, where internal channels shorten cycle times and pay for the insert in months. Manifolds and flow bodies that consolidate machined and welded assemblies. Food and pharmaceutical fittings with internal geometry that cannot be cleaned if it is welded. Spares for equipment whose drawings survive but whose tooling does not.
What it does not fix
Printed stainless is not cheaper than bar stock for a simple machined part, and it never will be. Surface finish is rough and features that must fit are machined afterwards. Corrosion behaviour of a printed surface differs from a polished wrought one, which matters in demanding service, and passivation and surface finishing are part of the specification rather than an afterthought.
Questions people ask about stainless steel 3d printing
Which stainless grades can be printed?
Austenitic grades for general corrosion resistance, precipitation hardening grades where strength matters, and martensitic tool steel grades for tooling inserts.
Is printed stainless as strong as wrought?
Comparable, and dependent on heat treatment and orientation. Precipitation hardening grades after solution treatment and ageing are strong; as built material is not the same thing.
Why print stainless rather than machine it?
For internal channels, consolidated assemblies and geometry that cannot be machined. For a simple part, machining from bar is cheaper and always will be.
Does printed stainless corrode differently?
The as built surface is rough and the microstructure differs from wrought material, so corrosion behaviour is not identical. Surface finishing and passivation are part of the specification.