Titanium and stainless steel both resist corrosion and both get specified for chemical, marine and process work, so buyers often have to choose between them. Titanium wins on corrosion in chlorides and on strength-to-weight, stainless wins on price and ease of fabrication, and there is a band of jobs where either would work and budget decides. This page compares the two on corrosion, strength, weight, temperature, fabrication and cost, and shows when each is the right call.
Titanium vs stainless steel at a glance
| Property | Titanium (Grade 2 / Grade 5) | Stainless steel (304 / 316) |
|---|---|---|
| Density | About 4.5 g/cm3 | About 8.0 g/cm3 |
| Chloride and seawater corrosion | Resists pitting, crevice and stress corrosion cracking | Can pit and crack in chlorides, more so when hot |
| Strength to weight | High, highest in Grade 5 | Lower |
| Reducing acids (HCl, H2SO4) | Limited, use Grade 7 or Grade 12 | Some high-alloy grades cope better |
| Upfront material cost | Higher | Lower |
| Life-cycle cost in seawater or chlorides | Lower, long maintenance-free life | Higher when pitting or cracking shortens life |
Corrosion resistance
Titanium is the stronger corrosion performer in chlorides and seawater. Its protective oxide film resists the pitting, crevice attack and chloride stress-corrosion cracking that take down 304 and 316 stainless in hot, salty water. Stainless steel relies on a chromium oxide film that breaks down once chlorides get concentrated and hot enough, which is why pitted heat-exchanger tubes and cracked stainless in seawater are common failures. Titanium handles seawater, wet chlorine, bleach and hot brine where stainless cannot.
| Property | Titanium | Stainless steel |
|---|---|---|
| Chloride and seawater corrosion | The stronger performer; its protective oxide film resists pitting, crevice attack and chloride stress corrosion | 304 or 316; 316 adds about 2 to 3 percent molybdenum, which lifts its resistance to chloride pitting above 304 |
| Strength | Grade 5 (Ti-6Al-4V) reaches about 895 MPa tensile | Roughly 515 MPa for annealed 316 |
| Density | Near 4.5 g/cm3 | About 8.0 g/cm3 |
| Weight for the same part | Roughly 44 percent less | Baseline |
Titanium is not immune to everything. In strong reducing acids such as hot hydrochloric or sulphuric acid, commercially pure titanium corrodes, and the answer there is Grade 7 (titanium-palladium) or Grade 12, not stainless. Hydrofluoric acid attacks titanium badly and must be avoided. For oxidising acids like nitric, both materials do well. The reason titanium resists what it resists is the passive film; the mechanism is covered in the guide on why titanium resists corrosion.
304 vs 316 vs titanium: the practical ladder
Most stainless decisions come down to 304 or 316. 316 adds about 2 to 3 percent molybdenum, which lifts its resistance to chloride pitting above 304, so 316 is the marine-grade stainless. Even so, 316 still pits and cracks in hot seawater and concentrated chlorides. The practical ladder is 304 for mild service, 316 for moderate chloride service, duplex or super-duplex stainless for harder chloride duty, and titanium where the chlorides are hot, concentrated or continuous. Titanium sits at the top of that ladder for chloride corrosion.
| Material | Where the guide places it on the ladder |
|---|---|
| 304 stainless | Mild service |
| 316 stainless | Moderate chloride service; 316 adds about 2 to 3 percent molybdenum, which lifts its resistance to chloride pitting above 304, so 316 is the marine-grade stainless |
| Duplex or super-duplex stainless | Harder chloride duty |
| Titanium | Where the chlorides are hot, concentrated or continuous |
The same ladder applies to the ancillary hardware around a process, not just the wetted parts. In commercial kitchen and food-processing exhaust, collector cells and housings are commonly specified in 304 or 316 stainless, with higher-grade materials reserved for the most aggressive sites. Polygee’s in-duct electrostatic precipitator is an example: it installs directly in the duct to capture grease and smoke before discharge, with washable cells that can be matched to the corrosion level of the site.
Strength and strength-to-weight
Grade 5 titanium (Ti-6Al-4V) reaches about 895 MPa tensile, well above the roughly 515 MPa of annealed 316 stainless, and it does it at about half the weight. Commercially pure Grade 2 titanium is close to 316 on raw tensile at 345 MPa but far lighter. On strength-to-weight titanium has no real competition, which is why it is the choice for aerospace, rotating parts and anything where mass costs money. Where raw strength alone matters and weight does not, high-strength stainless and duplex grades stay in the running.
Weight and density
Titanium has a density near 4.5 g/cm3 against about 8.0 g/cm3 for stainless steel, so a titanium part weighs roughly 44 percent less than the same part in stainless. On a vessel, a pump, a manifold or a structure, that is close to half the weight removed. For anything that moves, hangs, gets carried or has to be supported, the weight saving is the main reason titanium gets specified over stainless even when both would resist the medium.
High-temperature service
High heat is where stainless can win. Austenitic grades such as 310 and 321 hold strength and resist oxidation at sustained temperatures well above what titanium tolerates. Titanium starts to pick up oxygen and lose ductility as temperatures climb past a few hundred degrees, so for furnace, exhaust and high-temperature process parts, heat-resistant stainless or nickel alloys are usually the better answer. Titanium earns its place in wet, corrosive service at low to moderate temperature, not in dry high-heat duty.
| Point | What the guide states |
|---|---|
| High-temperature service | High heat is where stainless can win. Austenitic grades such as 310 and 321 hold strength and resist oxidation at sustained temperatures well above titanium’s range |
| Machining and welding | Stainless steel is easier and cheaper to machine and weld with common shop practice. Titanium needs lower cutting speeds, sharp tools and good coolant |
| Galvanic pairing | When titanium and stainless steel are bolted or welded together in a wet, conductive environment, titanium is the more noble metal and the stainless becomes the part that corrodes |
| Cost | Stainless steel costs less per kilogram and is the cheaper choice up front, often by a wide margin. Titanium costs more to extract, melt and machine |
Machining, welding and galling
Stainless steel is easier and cheaper to machine and weld with common shop practice. Titanium needs lower cutting speeds, sharp tools and good coolant, and it must be welded under inert gas shielding with tight contamination control or the weld turns brittle. Titanium also galls if it slides against itself or against stainless without lubrication or a surface treatment. Both metals are weldable and machinable; titanium simply demands more control and more cost on the shop floor, and that belongs in the decision.
Mixing titanium and stainless: galvanic notes
When titanium and stainless steel are bolted or welded together in a wet, conductive environment, titanium is the more noble metal and the stainless becomes the part that corrodes faster. Titanium itself shrugs off the couple. In seawater systems that mix the two, the stainless fasteners or flanges need attention, through isolation, coating or moving to titanium for those parts as well. It is a common detail that gets missed when a plant upgrades only the tubes to titanium and leaves stainless hardware in the same stream.
Cost and lifecycle
Stainless steel costs less per kilogram and is the cheaper choice up front, often by a wide margin. Titanium costs more to extract, melt and machine. The honest comparison is total cost over the life of the part. In corrosive service titanium can outlast stainless by years and remove the pitting, leaks, replacement and downtime that come with corroded stainless, and the weight saving can cut supporting steelwork and freight. For mild service, stainless is the economical answer; for hot chloride or seawater duty, titanium often costs less once the replacements are counted.
Which to choose
Choose titanium when the service is seawater, hot chlorides, wet chlorine or bleach, or when weight is critical; the corrosion life and the weight saving pay back the higher price. Choose stainless steel when the medium is within its limits and budget rules, or when the service is dry and hot where stainless holds up better. Many plants run both, putting stainless where it is safe and titanium where stainless would fail. The point is to match the metal to the real service, not to default to one for everything.
| Choose | What the guide states |
|---|---|
| Titanium | When the service is seawater, hot chlorides, wet chlorine or bleach, or when weight is critical |
Grades side by side
| Property | Ti Grade 2 (R50400) | Ti Grade 5 (R56400) | 304 stainless | 316 stainless |
|---|---|---|---|---|
| Tensile strength (min) | 345 MPa | 895 MPa | ~515 MPa | ~515 MPa |
| Density | 4.51 g/cm3 | 4.43 g/cm3 | ~8.0 g/cm3 | ~8.0 g/cm3 |
| Hot-chloride pitting/crevice | resists | resists | pits readily | better than 304, still pits |
| Chloride stress-corrosion cracking | immune | immune | susceptible | susceptible |
| Relative cost per kg | higher | highest | lowest | low |
Common questions
Is titanium stronger than stainless steel? Grade 5 titanium is much stronger than 316 stainless and at half the weight. Commercially pure Grade 2 is similar in tensile to 316 but far lighter.
Does titanium corrode less than stainless steel? In chlorides and seawater, yes. Titanium resists the pitting, crevice corrosion and chloride stress-corrosion cracking that attack 304 and 316 in hot, salty service.
Is 316 stainless as good as titanium for seawater? No. 316 resists more than 304, but it still pits and cracks in hot or stagnant seawater. Titanium holds up where 316 fails.
When is stainless steel the better choice? For mild or dry service, for high-temperature duty where titanium loses ductility, and where budget rules and the medium stays within stainless limits.
Why is titanium more expensive than stainless? Titanium is harder to extract, melt and machine. The payback comes from longer life in corrosive service and from the weight saving.
Can you weld titanium to stainless steel? Direct fusion welding of the two is not sound; they are usually joined mechanically or through a transition piece, and the galvanic couple has to be managed in wet service.
Beiyu Titanium is the international titanium export brand of Jiaxing Beiyu New Materials Technology Co., Ltd., with production backing in Baoji, Shaanxi. For a material-selection RFQ, send the required product form, grade, governing ASTM or AMS standard, dimensions, condition, quantity, application and inspection-document scope to [email protected]. To compare titanium grades first, use the titanium grades comparison guide, the Grade 2 page, the Grade 5 page and, for reducing-acid service, the Grade 7 page. If EN 10204 3.1 documentation or heat traceability is required, state the results and traceability fields needed so the available scope can be confirmed before order release.
Comparing across two material families changes what the certificate has to prove
A titanium and stainless comparison usually stops at properties. The part that decides a substitution in practice is documentary: the two families are accepted against different specification chains, and the titanium side has its own named test methods behind every figure quoted.
| What is reported on the titanium side | Method ASTM B348 references |
|---|---|
| Oxygen and nitrogen | ASTM E1409 |
| Hydrogen | ASTM E1447 |
| Carbon | ASTM E1941 |
| Tensile properties | ASTM E8, at the strain rate the specification sets, 0.003 to 0.007 in./in./min through the specified yield strength |
Naming a method settles how a value was produced. It does not add an examination the order did not request.
What a substitution enquiry should carry
| Line | Why a substitution in particular needs it |
|---|---|
| Service environment, not just the material name | The reason titanium is being considered is usually the environment, and it decides the grade |
| Governing titanium standard with the grade | The acceptance basis changes with the specification chain, not with the family |
| Section and tolerance | A stainless section is not automatically available in the same titanium form |
| Certificate and reporting scope | EN 10204 3.1 mill test certificate with heat number traceability, scope set by the order |
A substitution priced from a property table alone tends to arrive with paperwork that answers less than the receiving process expects.
Is steel harder than titanium? It depends which steel, and that is the useful answer
Hardness is where this comparison most often goes wrong, and the honest answer is that it depends on which steel. The hardness ranges of steel and titanium overlap: an annealed austenitic stainless can sit below annealed Grade 5 titanium, while a hardened tool or bearing steel can have substantially higher hardness than either. The result follows from the named grade and its heat-treated condition, not from the metal. Titanium is usually selected where low density and corrosion resistance are the design priorities, rather than for bulk hardness, which is a different property measured on a different scale.
| Material | Hardness as published on the Beiyu data sheets | Condition |
|---|---|---|
| Grade 2 titanium (CP, UNS R50400) | Typical values near 150 HB, or 160 to 200 HV | Annealed |
| Grade 5 titanium (Ti-6Al-4V, UNS R56400) | 30 to 36 HRC; the data sheet gives about 330 HV and 334 HB as approximate equivalents for the same condition | Annealed |
| Grade 5 titanium | Roughly 35 to 39 HRC | Solution treated and aged |
| Steel | Spans from soft mild steel to hardened tool and bearing grades | Depends entirely on grade and heat treatment |
The last row is the reason the question cannot be answered as it is usually asked. Steel is not one material. Its hardness range covers most of the practical scale, so a comparison against titanium is only meaningful once the steel grade and its heat-treated condition are named. Comparing titanium against unspecified steel produces an answer that changes with whichever steel the reader had in mind.
Hardness is not on the certificate, and that catches buyers out
There is a second trap that matters more on an order than in a discussion. Neither ASTM B265 nor ASTM B348 has a hardness column. Those are the specifications most titanium sheet, plate and bar is bought against, and they set chemical composition, mechanical properties and tolerances. Hardness is not among them.
Two consequences follow. A mill certificate issued to B265 or B348 is not required to report hardness, so a drawing that specifies a hardness limit is specifying something the governing standard does not verify. And material cannot be rejected on hardness against those standards, because there is no requirement in them to fail against. If a hardness limit is a real design requirement, it goes on the purchase order as an agreed additional test, with the method and the condition stated, in the same way a magnetic permeability limit does.
| What the drawing says | What a B265 or B348 certificate reports | What has to be agreed on the order |
|---|---|---|
| A hardness limit | Chemistry, tensile, yield, elongation. No hardness | The hardness scale, the limit, the test method and the delivery condition it applies to |
| Annealed condition, no hardness limit | Chemistry and mechanicals | Nothing further; the condition already sets the expected range |
| Solution treated and aged Grade 5 | Chemistry and mechanicals for that condition | Confirm whether the hardness figure is a requirement or a typical value being quoted for information |
What to compare instead when the part has to resist wear
If the reason for asking about hardness is wear, the comparison to run is not titanium against steel in the abstract. Titanium galls against itself and against many mating metals, which is a surface behaviour rather than a bulk hardness number, and it is handled by surface treatment, by choosing a dissimilar mating material, or by moving the wearing surface onto a different component. A part chosen in titanium for corrosion reasons and then asked to carry a sliding wear duty is the case where the specification usually needs to change, not the material.
Corrosion is the usual reason titanium is on the drawing instead of stainless, and the cases where titanium itself is attacked are set out in does titanium corrode.
The weight side of this comparison, with density by grade, kilograms per metre by bar size and the overweight allowance the standards set, is on is titanium heavy.
Specification detail with sources
The two passive films come from different alloy budgets, and the product standards state them. ASTM A240 holds type 316 at 16.0 to 18.0 percent chromium and 10.0 to 14.0 percent nickel, the reserve from which its chromium oxide film is maintained, while ASTM B265 defines Grade 2 titanium as unalloyed metal with iron capped at 0.30 percent and oxygen at 0.25 percent. Titanium’s film is grown from the base metal itself, which is why its chloride performance does not depend on an alloying reserve that hot concentrated brine can locally exhaust.
| Standard | Composition the guide cites |
|---|---|
| ASTM A240, type 316 | 16.0 to 18.0 percent chromium and 10.0 to 14.0 percent nickel, the reserve from which its chromium oxide film is maintained |
| ASTM B265, Grade 2 titanium | Unalloyed metal with iron capped at 0.30 percent and oxygen at 0.25 percent |
Procurement also splits by specification family, and quoting the right documents avoids mixed-standard orders. Wetted titanium is bought to ASTM B265 for sheet and plate, B348 for bar and B338 for exchanger tube, while the stainless counterparts are A240 for plate, A276 for bar and A312 for pipe, with the ASME SB and SA mirror documents taking over for code pressure work. EN 10204 defines the type 3.1 inspection certificate used across both families, so a project running titanium and stainless side by side can hold one documentation model while each heat is judged against its own standard’s tables.