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Should I use titanium or 17-4 PH stainless steel?
Use 17-4 PH H900 when you need maximum strength at lower cost: about 200 ksi (1,380 MPa) tensile versus 138 ksi (950 MPa) for Ti-6Al-4V, at roughly a quarter of the material price. Use titanium Grade 5 when weight, seawater or body fluids drive the design: it is about 43% lighter, non-magnetic, and has a better strength-to-weight ratio.
Titanium Grade 5 (Ti-6Al-4V)
Stainless steel 17-4 PH (H900)
By the numbers
Priced on the same representative part: plate, cnc machining, 50 pcs.
Tensile strengthMPa
Ti-6Al-4V
950
17-4 PH
1379
Yield strengthMPa
Ti-6Al-4V
880
17-4 PH
1275
Densityg/cm³
Ti-6Al-4V
4.43
17-4 PH
7.78
Max service temp°C
Ti-6Al-4V
400
17-4 PH
315
Elongation%
Ti-6Al-4V
14
17-4 PH
14
Raw material cost$/kg
Ti-6Al-4V
45
17-4 PH
12
Which should you pick?
Pick Ti-6Al-4V when
- Weight is the main constraint, as in aerospace, motorsport and cycling
- The part sees seawater, chlorides or body fluids
- It must be non-magnetic
- Service runs to about 750 °F (400 °C)
Pick 17-4 PH when
- You need the most strength or hardness per dollar
- Stiffness matters: about 28 Msi (196 GPa) versus 16.5 Msi (114 GPa)
- Shafts and valve parts slide or thread against other metals
- The machining budget is tight: about 45% versus 22% machinability
Key differences
| Ti-6Al-4V | 17-4 PH | |
|---|---|---|
| Machining | Slow; low thermal conductivity concentrates heat at the tool | Condition A is about 35 HRC; slow but manageable |
| Heat treatment | Usually used annealed | One aging step sets 145–200 ksi (1,000–1,380 MPa) |
| Magnetism | Non-magnetic | Magnetic |
| Galling | Galls in sliding contact; needs a coating or dissimilar mate | Less prone; still pair dissimilar materials in threads |
| Chloride corrosion | Excellent in seawater | Comparable to 304; pits in chlorides |
| Toughness option | Grade 23 ELI for fracture toughness and implants | H1025–H1150 for toughness; H900 has low impact toughness |
Questions
Is titanium stronger than stainless steel?
Than 304 and 316, yes, by a wide margin. Against 17-4 PH H900, no: 17-4 is stronger in absolute terms, about 200 ksi versus 138 ksi (1,380 vs 950 MPa). Titanium wins on strength per pound because it is about 43% lighter.
Is titanium worth the extra cost?
When weight, seawater or biocompatibility drive the design, often yes. Otherwise 17-4 PH delivers more strength for roughly a quarter of the material price and about twice the machinability rating, and titanium machining costs several times an equivalent aluminum part.
Which is better for medical instruments?
Both are used. 17-4 PH is common for surgical and dental instruments that need hardness. Titanium suits lightweight instruments and implant components, with Grade 23 ELI specified for implants under ASTM F136.
Try both on your part.
The builder prices the same geometry in every suitable process and material, with DFM for each.