Hotends and Nozzle Materials: Brass vs Hardened Steel

The nozzle is the small metal tip that the melted plastic comes out of. It sits at the end of the hotend, the heated assembly that melts the filament. Brass is the usual nozzle material, and hardened steel is the common upgrade for filament that wears brass away.

This is a research explainer based on maker documentation and store pages, checked on 2026-10-10. It is not a test. Always follow your own printer's guidance before swapping parts.

What a hotend and nozzle do

In fused filament fabrication, filament is fed from a spool through a heated extruder head and deposited layer by layer on the growing part. The hotend is the heated part of that head: it melts or softens the plastic and forms it into a thin continuous strand. The nozzle is the replaceable tip that sets the line width through its opening, which is why nozzle size matters for detail and speed.

The nozzle gets hot, and every gram of filament passes through it. That is why its material matters: it has to conduct heat, resist wear and, for some filaments, resist corrosion.

Brass nozzles

Prusa fits a brass nozzle to its FFF printers and says brass has excellent heat conductivity and is tough enough to print most common filaments. Its documentation describes the brass nozzle as cost-effective, easy to clean and a good fit for everyday printing with non-abrasive filaments.

The weakness is wear. Prusa states that a brass nozzle is not recommended for abrasive filaments, because they can cause rapid wear.

Prusa also sells brass variants for faster printing. Its CHT nozzle splits the filament flow into three streams for better heat distribution, which Prusa says enables higher speeds while keeping output consistent. Its E3D High Flow Brass nozzle splits the flow into four channels and, according to Prusa, works effectively at lower temperatures than conventional nozzles.

Hardened steel nozzles

Hardened steel is chosen for wear resistance. Prusa's documentation lists several options:

• ObXidian. A hardened steel nozzle with a coating. Prusa calls it particularly suitable for abrasive materials like carbon fiber, and says it keeps its hardness at higher temperatures. Prusa does not recommend cold pulls on it because they can tear off the coating, and advises cleaning with a non-abrasive cloth rather than needles or brass brushes.
• Hardened (nickel plated). Hardened steel with a nickel coating. Prusa says it offers good durability against abrasive filaments while reducing friction, and is suited to people who switch often between abrasive and non-abrasive materials.
• High Flow ObXidian. A hardened steel nozzle that combines abrasion resistance with heat tolerance and flow optimization, aimed at large prints or speed.
• DiamondBack. A nozzle with a polycrystalline diamond insert at the tip. Prusa says the tip is a solid diamond insert, not a coating, and positions it for metal and ceramic filled filaments.

Elegoo takes another route: it lists a 320 C hotend with a brass-hardened steel nozzle for its Centauri Carbon, described as heat and wear resistant. Check the maker's wording for which parts of the nozzle are hardened.

Stainless steel stock nozzles

Bambu Lab ships a 0.4 mm stainless steel nozzle with the A1 mini and P1S, each with an all-metal hotend rated to 300 C. The A1 mini specification table lists PLA, PETG, TPU and PVA as supported and carbon and glass fiber reinforced polymers as not recommended. The P1S table also lists carbon and glass fiber reinforced polymers as not recommended. Treat that as a signal to buy a hardened hotend or nozzle designed for your model before printing fiber-filled filaments.

Which filaments are abrasive?

Abrasive filaments contain hard particles that scrape the inside of the nozzle. The ones makers name most often are carbon fiber and glass fiber filled filaments. Prusa also lists metal and ceramic filled filaments among those suited to its DiamondBack nozzle. Check the filament maker's data sheet for any other filament you are unsure about.

Our guide to PETG-CF covers one filled material in more detail. For standard materials, see PLA, PETG, ABS and TPU compared.

Nozzle size and filled filaments

Prusa's compatibility chart gives these guidelines: a 0.25 mm nozzle is best for precision with PLA, ASA/ABS, PETG, PC blend and nylon, and it says to avoid flexible and composite materials. A 0.4 mm nozzle is versatile, and supports standard and composite materials when the nozzle is hardened. Sizes of 0.6 to 0.8 mm suit functional parts and faster printing, with potential warping with ASA and PC blend.

Choosing and swapping a nozzle

1. List the filaments you plan to print. If none are abrasive, stay with the stock nozzle.
2. If you want carbon fiber, glass fiber, metal or ceramic filled filament, buy a nozzle sold for your exact printer. Prusa nozzles differ between its Nextruder printers and E3D V6 printers, and an adapter exists to fit V6 nozzles to a Nextruder.
3. Update the nozzle type and diameter in the printer settings and slicer profile after the swap, and follow the maker's temperature guidance for that nozzle.
4. Use filament with tight diameter tolerance. Prusa recommends its own Prusament, quoting a diameter variation of plus or minus 0.02 mm, to avoid clogging.
5. Replace worn nozzles. If under-extrusion or clogs keep returning with no other cause, a worn or damaged nozzle is one thing to check; see fixing a clogged nozzle and fixing under-extrusion.

High-temperature hotends

Nozzle material is only half of the picture. Prusa sells an HT hotend upgrade for the CORE One L+ that it says reaches up to 400 C for engineering materials, and the same page mentions carbon-fiber reinforced PEKK and PPS. Most desktop printers max out far lower: Bambu Lab lists 300 C for the A1 mini and P1S, and Elegoo lists 320 C for the Centauri Carbon. Such materials also need an enclosure and the right build plate; see build plates compared.