When to Use Printing Steel？

Steel

Steel is the most common metal used in 3D printing. Its excellent material properties, versatility, and broad use in precision manufacturing make 3D printing steel an excellent option for creating high quality parts. Most types of steel can be printed, but the two types most commonly used are stainless steels and tool steels — metals that are more expensive and difficult to fabricate conventionally.

Positive attributes:

• excellent strength and stiffness
• wide variety of material properties
• heat treatable.

Stainless steels are strong, stiff steels that possess excellent corrosion resistance due to their significant chromium content (at least 12%, often up to 18%). Two types of stainless steels are commonly printed: austenitic and martensitic.

• Austenitic stainless steels, the most common type of stainless steels, are corrosion resistant and can be both machined and welded, though they cannot be heat treated. 316L is common 3D printed stainless steel known for its superior corrosion resistance.
• Martensitic stainless steels are much harder than austenitic steels, but more brittle and less corrosion resistant. 17-4 PH is a martensitic stainless steel that can be heat treated to fit a variety of material properties and is broadly used throughout manufacturing.

Tool steels are named for their central application – tooling of all varieties. They contain carbide, an extremely hard compound that’s critical to their ability to cut, grind, stamp, mold, or form. Generally, they’re very hard, abrasion resistant, and many are usable at high temperatures. The three types most commonly metal 3D printed are A series, D series, and H series tool steels.

• A Series tool steels are great general-use, machinable tool steels that balance wear resistance and toughness. There are eight varieties of A Series, the most common of which is A2 tool steel. It’s a versatile, cold-work tool steel often used to make punches and dies, as well as a wide variety of other applications.
• D Series tool steels are optimized for wear resistance and hardness. They’re not particularly tough and are only used for cold work applications. The most common variety in the D Series is D2 steel, a cold-work tool steel used for all kinds of cutting tools, from blades to industrial cutting tools and knives.
• H Series tool steels cut and shape material at high (or cycling) temperatures. H13 is the most common 3D printed hot-work tool steel. Its mix of excellent 3D printed metal strength, toughness, wear resistance, and heat resistance make it a good general use tool steel that’s optimized for use in high temperatures.

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Thermal conductivity of brass is approximately twice as better than steel (not stainless). Given that the size of nozzle is relatively small, it should be able to transfer enough heat for a medium-speed prints at least. I have printed PLA and ABS using "steel" nozzle (brand of steel unknown) at the speed around 80 mm/s without any visible differences compared to brass.

However, an ideal nozzle (I see) is made of tempered bronze with polished inner channels. Bronze is known to have better friction coefficient and tempered one should be enough to resist carbon-type filaments more efficiently.