# CNC Material Selection by Alloy Family

> CNC material selection guides compared by alloy family: aluminum, steel, stainless steel, titanium, copper alloys, superalloys and engineering plastics, with machinability and cost trade-offs.

https://www.sinbo-machining.com/wiki/materials/

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# 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 ](https://www.sinbo-machining.com/wiki/processes/)[, and for how tightly it can be held, Tolerances ](https://www.sinbo-machining.com/wiki/tolerances/). Alloy Families at a Glance - [Aluminum 6061, 7075, 5052 and related alloys — the default choice when weight, corrosion resistance and cost beat absolute strength ](https://www.sinbo-machining.com/wiki/materials/aluminum/)
- [Steel 1045, 4140, 4340 — high strength and wear resistance at the lowest material cost per part ](https://www.sinbo-machining.com/wiki/materials/steel/)
- [Stainless Steel 304, 316, 303, 17-4PH, 2205 — corrosion resistance and hygienic surfaces, ordered by what the environment actually attacks ](https://www.sinbo-machining.com/wiki/materials/stainless-steel/)
- [Titanium Grade 2 vs Ti-6Al-4V — when the strength-to-weight ratio and biocompatibility justify the machining difficulty ](https://www.sinbo-machining.com/wiki/materials/titanium/)
- [Copper & Brass C36000 free-machining brass, C17200 beryllium copper, C11000 — conductivity, non-sparking and galling resistance ](https://www.sinbo-machining.com/wiki/materials/copper/)
- [Superalloys Inconel 718, 625, Hastelloy C-276, Monel 400 — high-temperature and corrosive service where the material sets the process ](https://www.sinbo-machining.com/wiki/materials/superalloys/)
- [Engineering Plastics POM, PEEK, Nylon, PTFE — decision table on stiffness, wear, moisture uptake and achievable tolerance ](https://www.sinbo-machining.com/wiki/materials/plastics/)
Within-Family Decisions - [316L vs 304 Stainless Steel Composition, corrosion resistance, the real cost gap, weldability, and a decision rule for when the upgrade pays for itself ](https://www.sinbo-machining.com/wiki/materials/stainless-316l-vs-304-selection/)
- [F136 vs F136 ELI Titanium Interstitial control, fatigue and toughness for implants — and when Grade 5 is acceptable instead ](https://www.sinbo-machining.com/wiki/materials/f136-vs-f136-eli-titanium-implant/)
- [P20 vs H13 vs S7 vs D2 Hardness, composition and a decision tree for injection moulds, die inserts and long-life cutting tools ](https://www.sinbo-machining.com/wiki/materials/p20-vs-h13-vs-s7-vs-d2-tool-steel/)
[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 ](https://www.sinbo-machining.com/wiki/applications/)[, Processes ](https://www.sinbo-machining.com/wiki/processes/)[, or Tolerances ](https://www.sinbo-machining.com/wiki/tolerances/).