Nozzle Materials Decoded: Brass, Steel, Hardened Steel, Tungsten Carbide, Ruby

Every nozzle material is a trade between how fast it moves heat into plastic and how well it resists being sanded away from the inside. You cannot max both, so pick for what you actually print.

Brass — the default, and usually right

Thermal conductivity around 110 W/m·K. Nothing common beats it for getting heat into filament, which is why brass stays the highest-flow option for unfilled materials. It is also soft. Carbon fibre, glass fill, metal fill, glow powder, and wood fill will open a 0.4 mm brass nozzle to 0.5 mm inside a couple of spools.

Use it for: PLA, PETG, ABS, ASA, TPU — anything unfilled. Replace when your extrusion widths start drifting.

Stainless steel — the food-safe compromise

Roughly 15 W/m·K, so seven times worse at heat transfer than brass, and only mildly more wear resistant. Its real reason to exist is that it contains no lead and is accepted for food-contact-adjacent prints.

Use it for: food-adjacent parts and nothing else. Expect to raise temperatures 5–10 °C to match brass flow.

Hardened steel — the abrasive workhorse

Around 20 W/m·K with a hardened or coated bore. This is the right answer for filled filaments and it is cheap. The downside is real but manageable: slightly lower flow and a surface that some users find holds onto residue more than brass.

Use it for: carbon fibre, glass filled, glow in the dark, wood fill, metal fill, anything with visible particles.

Tungsten carbide — the long-haul option

Extreme hardness with conductivity in the 70–90 W/m·K range, so it recovers most of the flow that hardened steel gives up. It will outlast hardened steel by an order of magnitude on abrasives. It is also brittle: drop it on concrete and it can chip, and over-torquing can crack it.

Use it for: production machines running filled materials constantly, where nozzle swaps cost more than the nozzle.

Ruby and plated tips — precision, at a price

A synthetic ruby insert in a brass or copper body gives you brass-class conductivity with a wear surface that is essentially permanent. Nickel-plated copper does something similar with a coating instead of an insert. Both are excellent and both are expensive enough that you should be sure abrasives are a permanent part of your workflow.

Use it for: fine-detail abrasive printing where you also want maximum flow.

The part people get wrong

Nozzle material changes your effective temperature, not just your wear life. Swapping brass for hardened steel without raising temperature is the most common cause of sudden under-extrusion after an "upgrade." When you change material, re-run a temperature tower. Ten minutes, and it saves a week of chasing ghosts.

Diameter matters more than material for most people

If you print functional parts and you have never left 0.4 mm, try 0.6 mm before you spend money on exotic alloys. You get roughly twice the flow, stronger parts from wider extrusions, and a nozzle far less prone to blocking — at the cost of detail you probably were not using.