Beyond Titanium:

What It Takes to Machine Aerospace Alloys

In aerospace machining, the materials involved are as extreme as the environments they’re built for. Heat, pressure, corrosion, and structural load — the alloys used in this industry have to endure it all. But those same properties that make them ideal for flight also make them some of the most punishing materials to machine.

Following our deep dives into material behavior and titanium, this post explores three other aerospace alloys that push machines — and machinists — to the limit: Inconel, Super Duplex Stainless, and Heat-Treated Steels.

Inconel: Resistant to Everything, Except Tool Life

Inconel is a family of nickel-based superalloys designed to withstand high temperatures, extreme pressure, and corrosive environments — making it indispensable in jet engines, turbine blades, and exhaust components.

Why It’s So Demanding:

  • Work-hardens rapidly, meaning the longer your tool is in contact, the harder the material becomes.

  • Low thermal conductivity keeps heat at the cutting edge, accelerating tool wear.

  • High strength at elevated temperatures means tool deflection is a constant risk.

Machining Considerations:

  • Must be machined slowly, with very consistent feeds to avoid surface hardening.

  • Requires rigid setups, high-pressure coolant, and specialty tooling.

  • Any hesitation or dwell marks can destroy a finish or tolerance.

Aerospace Use Cases: Turbine blades, exhaust systems, structural fasteners in high-heat zones.

Super Duplex Stainless: Corrosion Resistance Comes at a Cost

Super Duplex alloys (like 2507 or Zeron 100) are dual-phase stainless steels combining high strength with exceptional corrosion resistance — particularly in chloride-rich or high-pressure environments.

Why It’s So Demanding:

  • High chromium and molybdenum content increases strength, but also makes the material tough and abrasive to cut.

  • The duplex structure can lead to uneven machining behavior, as different hardness phases cause chatter and tool bounce.

Machining Considerations:

  • Generates high cutting forces, requiring powerful machines and stable fixturing.

  • High-performance carbide tooling and optimized feeds/speeds are a must.

  • Excessive heat can cause phase imbalance and microstructural issues.

Aerospace Use Cases: Landing gear components, structural supports, high-pressure fuel or hydraulic systems.

Heat-Treated Steels: Engineered Toughness, Extreme Precision

Alloys like 4340, 15-5PH, or H13, once heat-treated, gain tremendous strength and fatigue resistance — essential for aerospace parts that undergo repeated stress, like actuators or gears.

Why It’s So Demanding:

  • Hardness increases exponentially after heat treatment, making cuts slower and tooling costs higher.

  • Surface finish matters — but finishing cuts are hard to control in hardened materials.

  • Requires meticulous planning to maintain tolerances and avoid rework.

Machining Considerations:

  • Machining is often done in the annealed state, then heat-treated — but not always.

  • Post-heat treatment work demands rigid setups and ceramic or coated tooling.

  • Cycle times increase dramatically — and mistakes are far more costly.

Aerospace Use Cases: Gears, shafts, hydraulic system components, landing gear pivots.

What All These Materials Have in Common

🛠️ They’re difficult to machine.
 ⚙️ They require specialized equipment, tooling, and expertise.
 📐 Precision isn’t optional — it’s engineered into the material requirements.

If your supplier isn’t experienced with these materials, the risks go up: missed tolerances, scrap parts, extended lead times, and spiraling costs.

How We Approach Aerospace-Grade Machining

At Made In America Manufacturing, we don’t just accept the challenge of machining superalloys — we’re built for it.

  • Rigid, high-horsepower machines

  • Real-time tool life monitoring

  • Full 5-axis capability for complex geometries

  • CMM-based 100% inspection on mission-critical parts

We understand how these materials behave — and how to get it right the first time.

📌 Missed the earlier blogs?

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