Material selection
Titanium Grade 5 (Ti-6Al-4V) vs Stainless 304
Trumould CNC-machines both in-house, and both hold up in service, so the choice usually comes down to what the part has to weigh and what it has to cost. The numbers below are the same published values used on each material's own page, set side by side.
| Titanium Grade 5 | Stainless 304 | |
|---|---|---|
| Density | 4.43 g/cm³ | 8.00 g/cm³ |
| Tensile strength | 950 MPa | 515 MPa |
| Yield strength | 880 MPa | 205 MPa |
| Elongation | 14 % | 40 % |
| Hardness | 334 HB | 201 HB max |
| Melting range | 1604–1660 °C | 1400–1450 °C |
| Relative cost | Very high | Medium |
Published values for standard grades at 23 °C unless stated, taken from each material's own datasheet page. Confirm against the supplier datasheet for the grade you specify.
What Titanium Grade 5 is
Ti-6Al-4V accounts for the majority of titanium used worldwide. It has the tensile strength of a heat-treated alloy steel at 56 % of the density, is essentially immune to seawater and body-fluid corrosion, and is fully biocompatible. It is difficult and expensive to machine: low thermal conductivity concentrates heat at the cutting edge, and the material is chemically reactive with most tool coatings at temperature.
What Stainless 304 is
304 is an austenitic chromium-nickel stainless and the most used stainless grade worldwide. The chromium forms a passive oxide film that reforms if scratched, which is what gives the alloy its corrosion resistance. It is very ductile, deep draws well, and welds without special procedure. It also work hardens aggressively, which makes machining slow and expensive compared with aluminum, though nowhere near as slow or as expensive as titanium.
Titanium Grade 5 against Stainless 304
| Titanium Grade 5 | Stainless 304 | |
|---|---|---|
| Weight | 4.43 g/cm³, a little over half the density of stainless 304 | 8.00 g/cm³, close to twice the density of titanium for the same volume |
| Strength | 950 MPa tensile, 880 MPa yield, the strength of a heat-treated alloy steel at well under half the weight | 515 MPa tensile, 205 MPa yield, lower on both counts but far more ductile at 40 % elongation against 14 % |
| Corrosion resistance | Essentially immune to seawater and body-fluid corrosion, and fully biocompatible; the reference standard for implants and marine hardware | Passive chromium oxide film reforms on its own if scratched; resists general atmospheric and mild chemical exposure well, but not to titanium's standard in seawater, chlorides, or body fluids |
| Machinability | Difficult and slow. Low thermal conductivity concentrates heat at the cutting edge, and the material reacts with most tool coatings at temperature | Work hardens aggressively with dwelling in the cut, which slows machining and raises cost, but the part still machines in a fraction of the time and tooling cost titanium needs |
| Galling and compatibility | Galls against itself and against stainless under threaded or sliding contact; specify a coating or a dissimilar mating material at any such interface | Does not gall against itself the way titanium does, but the same interface caution applies wherever it mates directly against titanium |
| Relative cost | Very high: both the raw material and the machining time run well above stainless, let alone aluminum | Medium: costs more to machine than aluminum because of work hardening, but far less than titanium in material and machining time combined |
Which one, for which part
- Orthopaedic implants, surgical instruments, or any part that must be biocompatible is titanium's case outright; 304 is not an implant-grade material and has no real substitute here.
- Weight-critical or aerospace-adjacent parts, aircraft structure, motorsport components, robotic end effectors, anything carried or moved by another mechanism, favour titanium at roughly 56 % of stainless's density for comparable or higher strength.
- Marine or continuous chloride and body-fluid exposure beyond what a passive oxide film reliably handles favours titanium; where the budget will not stretch that far, stainless 316L is the usual next step up from 304, not 304 itself.
- General corrosion resistance for food, beverage, architectural, or washdown hardware, where weight and biocompatibility are not the deciding constraint favours 304 at a fraction of titanium's material and machining cost.
- A threaded fastener, pin, or sliding interface where the two materials would mate directly needs a coating or a dissimilar third material, bronze or a plated fastener are common choices, because titanium galls against stainless in direct contact.
- Machined housings, brackets, and general production parts on a machining budget favour 304, or aluminum where corrosion resistance is not required at all; titanium is an expensive way to buy strength on a part that does not genuinely need the weight, corrosion, or biocompatibility case for it.
Our status
Trumould machines both titanium Ti-6Al-4V and stainless 304 in-house on the same CNC equipment; this comparison covers that CNC-machined route, where the two compete directly for the same part. Titanium is also available here through 3D printing for lattice geometry where the cost case works, and 304 is also available through sheet metal fabrication for formed enclosures, but neither material runs through injection molding at Trumould. Send the part, its service environment, and target volume, and the quote states which of the two is recommended and why, not just a price for whichever one you asked about first.
Specifying this part?
Send your CAD and target volumes. We come back with a price, a lead time, and any material or design notes that would reduce either.