CNC Material Selection by Alloy Family
Material choice drives almost everything downstream: cycle time, tool life, achievable tolerance, corrosion performance, and final cost. This section groups the alloy families a CNC buyer actually specifies between, and answers the only question that matters at the drawing stage — which family does this part belong in, and which grade inside it?
How to use this section.
Start at the alloy family that matches your part's service environment, then use the dedicated page for the within-family comparison. Pages here cover material behaviour and selection logic; for how the part is actually cut, see Processes, and for how tightly it can be held, Tolerances.
Alloy Families at a Glance
- Aluminum6061, 7075, 5052 and related alloys — the default choice when weight, corrosion resistance and cost beat absolute strength
- Steel1045, 4140, 4340 — high strength and wear resistance at the lowest material cost per part
- Stainless Steel304, 316, 303, 17-4PH, 2205 — corrosion resistance and hygienic surfaces, ordered by what the environment actually attacks
- TitaniumGrade 2 vs Ti-6Al-4V — when the strength-to-weight ratio and biocompatibility justify the machining difficulty
- Copper & BrassC36000 free-machining brass, C17200 beryllium copper, C11000 — conductivity, non-sparking and galling resistance
- SuperalloysInconel 718, 625, Hastelloy C-276, Monel 400 — high-temperature and corrosive service where the material sets the process
- Engineering PlasticsPOM, PEEK, Nylon, PTFE — decision table on stiffness, wear, moisture uptake and achievable tolerance
Within-Family Decisions
- 316L vs 304 Stainless SteelComposition, corrosion resistance, the real cost gap, weldability, and a decision rule for when the upgrade pays for itself
- F136 vs F136 ELI TitaniumInterstitial control, fatigue and toughness for implants — and when Grade 5 is acceptable instead
- P20 vs H13 vs S7 vs D2Hardness, composition and a decision tree for injection moulds, die inserts and long-life cutting tools
Industry vs part.
Most industries specify the same set of alloys covered here. The industry pages translate “I’m making a part for X” into the right material callout, tolerance scheme, certification and inspection regime. For the underlying depth, jump to Applications, Processes, or Tolerances.