Engineering · Materials
Materials reference & selection guide.
Side-by-side comparisons of the common engineering alloys. Pick on properties — not just on what's specified by default.
Interactive tool
Materials performance spectrum compass.
Select a material class to trace its alloys on our specific strength vs. machinability grid. Hover over individual alloy nodes for detailed mechanical limits, shop verdicts, and tooling advice.
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Aluminum Alloys
Advantages
Limitations
Target Applications
Shop Floor Machining Secret
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At a glance
Strength, weight, and machinability — compared.
Three properties drive most material decisions: how strong, how heavy, and how hard to cut. Here’s how the alloys in this reference stack up across all three.
| Material | Tensile | Yield | Density | Machinability | Stiffness | Cost |
|---|---|---|---|---|---|---|
| 6061-T6 Aluminum | 310 MPa · 45 ksi | 276 MPa | 2.70 g/cc · 0.097 lb/in³ | 90 index | 68.9 GPa | $4–6 /lb |
| 7075-T6 Aerospace aluminum | 572 MPa · 83 ksi | 503 MPa | 2.81 g/cc · 0.101 lb/in³ | 70 index | 71.7 GPa | $7–9 /lb |
| 2024-T3 Aerospace aluminum | 470 MPa · 68 ksi | 325 MPa | 2.78 g/cc · 0.100 lb/in³ | 80 index | 73.1 GPa | $7–9 /lb |
| 4140 Steel Alloy steel | 950 MPa · 138 ksi | 860 MPa | 7.85 g/cc · 0.283 lb/in³ | 65 index | 200 GPa | $2–4 /lb |
| 4340 Steel Alloy steel | 1280 MPa · 186 ksi | 1100 MPa | 7.85 g/cc · 0.283 lb/in³ | 50 index | 200 GPa | $4–7 /lb |
| 4130 Chromoly Alloy steel | 670 MPa · 97 ksi | 435 MPa | 7.85 g/cc · 0.283 lb/in³ | 70 index | 200 GPa | $2–3 /lb |
| A2 Tool Steel Tool steel | 2000 MPa · 290 ksi | 1900 MPa | 7.86 g/cc · 0.284 lb/in³ | 70 index | 207 GPa | $5–8 /lb |
| D2 Tool Steel Tool steel | 2000 MPa · 290 ksi | 1900 MPa | 7.70 g/cc · 0.278 lb/in³ | 50 index | 207 GPa | $6–10 /lb |
| H13 Tool Steel Tool steel | 1700 MPa · 246 ksi | 1450 MPa | 7.80 g/cc · 0.282 lb/in³ | 75 index | 207 GPa | $6–10 /lb |
| 316L Stainless Austenitic stainless | 580 MPa · 84 ksi | 290 MPa | 8.00 g/cc · 0.289 lb/in³ | 45 index | 193 GPa | $7–10 /lb |
| 17-4PH Stainless PH stainless | 1310 MPa · 190 ksi | 1170 MPa | 7.75 g/cc · 0.280 lb/in³ | 45 index | 196 GPa | $10–14 /lb |
| 17-7PH Stainless PH stainless | 1310 MPa · 190 ksi | 1170 MPa | 7.81 g/cc · 0.282 lb/in³ | 35 index | 200 GPa | $11–15 /lb |
| Ti-6Al-4V Titanium | 950 MPa · 138 ksi | 880 MPa | 4.43 g/cc · 0.160 lb/in³ | 22 index | 113.8 GPa | $40–60 /lb |
| Inconel 718 Nickel superalloy | 1380 MPa · 200 ksi | 1035 MPa | 8.19 g/cc · 0.296 lb/in³ | 12 index | 200 GPa | $35–50 /lb |
| C110 Copper Pure copper | 220 MPa · 32 ksi | 70 MPa | 8.94 g/cc · 0.323 lb/in³ | 20 index | 117 GPa | $5–10 /lb |
| C932 Bronze Bearing bronze | 240 MPa · 35 ksi | 125 MPa | 8.90 g/cc · 0.321 lb/in³ | 70 index | 100 GPa | $8–15 /lb |
| BeCu C172 Cu-Be alloy | 1310 MPa · 190 ksi | 1100 MPa | 8.36 g/cc · 0.302 lb/in³ | 40 index | 131 GPa | $50–90 /lb |
| Brass C360 Free-machining brass | 410 MPa · 59 ksi | 310 MPa | 8.50 g/cc · 0.307 lb/in³ | 100 index | 97 GPa | $4–7 /lb |
| Magnesium AZ31 Magnesium | 285 MPa · 41 ksi | 200 MPa | 1.78 g/cc · 0.064 lb/in³ | 100 index | 45 GPa | $15–25 /lb |
| Hastelloy C-276 Nickel superalloy | 790 MPa · 115 ksi | 360 MPa | 8.89 g/cc · 0.321 lb/in³ | 18 index | 205 GPa | $50–80 /lb |
| Monel 400 Nickel alloy | 550 MPa · 80 ksi | 240 MPa | 8.80 g/cc · 0.318 lb/in³ | 35 index | 179 GPa | $15–25 /lb |
| Delrin / POM Engineering plastic | 70 MPa · 10 ksi | 70 MPa | 1.42 g/cc · 0.051 lb/in³ | 80 index | 3.1 GPa | $5–10 /lb |
| Ultem (PEI) Engineering plastic | 105 MPa · 15 ksi | 105 MPa | 1.27 g/cc · 0.046 lb/in³ | 70 index | 3.2 GPa | $40–60 /lb |
| PEEK Engineering plastic | 100 MPa · 14 ksi | 100 MPa | 1.32 g/cc · 0.048 lb/in³ | 65 index | 3.6 GPa | $100–200 /lb |
Click any column heading to rank the alloys. Machinability is a relative machinability index (family-specific scales: steels vs AISI B1112 = 100; copper alloys vs C360 = 100; tool steels vs W1 = 100) — compare within a family only (higher = easier to cut). Select a material to open its full datasheet.
The trade-off
Strength, weight, and machinability rarely all favor one material. Pick two.
- Lightweight + strong? Titanium.
- Strong + cheap to machine? 17-4PH or 4140.
- Light + cheap? Aluminum 6061.
- High-temp strength? Inconel 718.
The catalog
Material machining references.
Aluminum
6061-T6
Aluminum 6061-T6
The general-purpose aluminum. Easy to machine, easy to weld, easy to anodize. Goes in everything from drone frames to aerospace structures.
- Aerospace structures
- Robotics
- Optics
- General
Aerospace aluminum
7075-T6
Aluminum 7075-T6 (UNS A97075)
High-strength aerospace aluminum. ~85% higher strength than 6061 at a small density penalty. Standard for primary aircraft structures and weapon platforms.
- Aerospace
- Defense
- Sporting
- Precision
Aerospace aluminum
2024-T3
Aluminum 2024-T3 (UNS A92024)
The classic aircraft skin alloy. Outstanding fatigue resistance from copper alloying. On virtually every commercial fuselage and wing.
- Aircraft skins
- Airframes
- Precision plate
Alloy steel
4140 Steel
AISI 4140 Cr-Mo Alloy Steel
The bread-and-butter alloy steel. Strong, tough, hardenable, cheap. Pair with plating or paint for any environment that sees moisture.
- Shafts
- Hydraulics
- Gears
- Industrial
Alloy steel
4340 Steel
AISI 4340 Ni-Cr-Mo Alloy Steel
Premium aerospace alloy steel. Deep hardenability + nickel toughness. Standard for landing gear, helicopter shafts, and large high-stress sections.
- Aerospace landing gear
- Drive shafts
- Heavy industry
Alloy steel
4130 Chromoly
AISI 4130 Cr-Mo Alloy Steel
The weldable Cr-Mo alloy steel. Aircraft tubing, race car frames, firearms barrels — anywhere weldability + strength matters.
- Aircraft tubing
- Motorsport
- Firearms
Tool steel
A2 Tool Steel
AISI A2 Air-Hardening Cold-Work Tool Steel
The tool-room workhorse. Air-hardens with minimal distortion to 60+ HRC. Punches, dies, gauges, hardened fixturing components.
- Tooling
- Dies
- Gauges
- Fixturing
Tool steel
D2 Tool Steel
AISI D2 High-Cr Cold-Work Tool Steel
High-chromium cold-work for max wear. 12% Cr forms hard carbides. Best abrasion resistance; more brittle than A2.
- Blanking dies
- Abrasive tooling
- Knife steel
Tool steel
H13 Tool Steel
AISI H13 Hot-Work Tool Steel
Hot-work standard. Holds 44 HRC at 540 °C continuous service. Aluminum die casting, hot forging, plastic molds.
- Die casting
- Hot forging
- Plastic molds
Austenitic stainless
316L Stainless
Stainless Steel 316L (UNS S31603)
Low-carbon austenitic stainless. Excellent corrosion resistance, especially in chloride environments. Standard for medical, food, and marine.
- Medical
- Food / pharma
- Marine
- Cryogenic
PH stainless
17-4PH Stainless
Stainless Steel 17-4PH (UNS S17400)
Precipitation-hardening stainless. Strength of alloy steel + corrosion resistance of stainless. Aerospace landing gear, hydraulic valves, shafts.
- Aerospace
- Hydraulics
- Defense
- Marine
PH stainless
17-7PH Stainless
Stainless Steel 17-7PH (UNS S17700)
Semi-austenitic PH stainless. Forms easily annealed, then ages to high strength. Standard for stainless springs and aerospace formed fittings.
- Springs
- Aerospace bellows
- Formed fittings
Titanium
Ti-6Al-4V
Titanium Grade 5 (Ti-6Al-4V)
The aerospace & medical workhorse. Outstanding strength-to-weight, biocompatible, corrosion-resistant. Difficult to machine — but worth it.
- Aerospace
- Medical implants
- High-temp
Nickel superalloy
Inconel 718
Inconel 718 (UNS N07718)
Nickel superalloy that holds strength up to 700°C. The standard for jet-engine hot-section parts, gas turbines, and high-pressure energy applications.
- Jet engines
- Gas turbines
- Energy
- Cryogenic
Pure copper
C110 Copper
Electrolytic Tough Pitch Copper (UNS C11000)
100% IACS conductivity reference standard. Bus bars, electrical contacts, RF housings, heat sinks — anywhere current or heat needs to flow.
- Electrical
- RF / microwave
- Thermal mgmt
Bearing bronze
C932 Bronze
Bearing Bronze SAE 660 (UNS C93200)
The bushing-and-bearing default. Self-lubricating, anti-galling against steel, marine-corrosion resistant. Pumps, valves, marine hardware.
- Bushings
- Valve guides
- Marine
Cu-Be alloy
BeCu C172
Beryllium Copper (UNS C17200)
Strongest copper alloy. Conductivity + spring + non-sparking + EDM electrode. Special handling required for beryllium dust.
- Springs
- EDM electrodes
- Non-sparking tools
Free-machining brass
Brass C360
Free-Cutting Brass (UNS C36000)
The screw-machine standard. Lead inclusions break chips for fastest cutting. Fittings, valves, fasteners, plumbing hardware.
- Screw machine
- Fittings
- Plumbing
Magnesium
Magnesium AZ31
Magnesium Alloy AZ31B (UNS M11311)
Lightest commonly-machined structural metal. Excellent damping. Aerospace, electronics, optics. Fire-safe machining required.
- Aerospace lightweight
- Electronics
- Racing
Nickel superalloy
Hastelloy C-276
Ni-Cr-Mo-W Superalloy (UNS N10276)
The corrosion-resistance king. Survives reducing acids, chlorides, sour gas, hot caustic. Chemical processing, scrubbers, sour gas wells.
- Chemical proc.
- Pollution control
- Sour gas
Nickel alloy
Monel 400
Ni-Cu Alloy (UNS N04400)
Nickel-copper alloy bridging stainless and Hastelloy. Marine, HF acid, reducing media. Pump shafts, propellers, naval hardware.
- Marine
- Chemical
- Naval
- Oil & gas
Engineering plastic
Delrin / POM
Acetal Homopolymer (Polyoxymethylene)
The general-purpose engineering plastic. Strong, stiff, low-friction, easy to machine. Gears, bushings, snap-fits, valves, wear parts.
- Gears
- Bushings
- Fluid handling
Engineering plastic
Ultem (PEI)
PolyEtherImide (Sabic Ultem 1000)
Amber transparent high-temp plastic. FAR 25.853 aircraft cabin compliant, sterilizable, low outgassing. Aerospace interiors, semi handlers.
- Aircraft interiors
- Semiconductor
- Sterilizable medical
Engineering plastic
PEEK
PolyEtherEtherKetone (Victrex 450G)
Premium engineering thermoplastic. Continuous service to 250 °C, biocompatible, chemical-resistant. The non-metal answer for harsh environments.
- Aerospace seals
- Medical implants
- Semiconductor
- Oil & gas
Don’t see your material? For additional alloys, confirm stock availability, process suitability and production scope before quoting. Reach out for specifics.
Pricing: typical Q1 2026 stock costs per lb, mid-quantity bar/plate. Real prices vary with mill, lot size, certification (CMTR, vacuum-melted, aerospace traceable), and market conditions. Use as planning estimates — request formal quotes for production buys.
Need help picking a material?
Tell us about your part and we'll get back to you promptly. Aerospace, medical, defense, and semiconductor production work welcome.Email CAD models and drawings to sales@digitalmachine.com, including ITAR, EAR, CUI and AS9100 work. Keep controlled technical data out of web forms.
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