Additive Manufacturing: 17-4PH vs. CX Powder Performance

 

Why gas-atomized 17-4PH dominates aerospace AM?
Spheroidal powder (15-45μm) achieves >99.5% density after SLM. H900 aging delivers 1,310 MPa UTS matching wrought properties. Cost: $120/kg vs. CX's $350/kg.

 

When copper-strengthened CX is specified?
For conformally cooled injection molds requiring 200 W/m·K thermal conductivity. Precipitation-hardened Cu-Ni-Sn matrix withstands 100,000+ cycles. Wear resistance 3x higher than H13 tool steel.

 

Critical powder characteristics?
Flowability: <25 s/50g Hall flow
Oxygen content: <300 ppm for 17-4PH, <100 ppm for CX
Satellites: <0.5% by particle count
Recyclability: ≤5 uses before property degradation

 

Post-processing requirements?
Stress relief: 650°C/1hr for 17-4PH (prevents HAZ cracking)
HIP: 1,180°C/100 MPa/4hr for CX (eliminates microporosity)
Surface finish: As-built Ra 10μm → Machined to Ra 0.8μm

 

Qualification testing protocol?
Tensile tests at 0°, 45°, 90° to build direction. Fatigue testing >10⁷ cycles. CT scans for internal defects. Chemical analysis per ASTM E1941.