Titanium Grade Selection Guide

The three-question method

Most grade mistakes come from starting at the wrong end — picking a grade because it was used somewhere similar, rather than because it answers the actual requirements. Work through the three questions in order and the field narrows quickly.

Question 1: what is the environment?

Corrosion governs more titanium specifications than strength does. The relevant variables are the medium and its concentration, temperature, whether the environment is oxidising or reducing, whether crevices exist, and whether there is erosion or high flow velocity.

• Oxidising media, seawater, chlorides, nitric acid — Grade 2 covers almost everything here.
• Reducing dilute acids, hot crevices — Grade 7 enters the discussion.
• Hot chloride and brine above roughly 70 °C — Grade 12 is usually specified.
• Ambient seawater or chest-type service — Grade 2 and stop thinking about it.

Question 2: how much load?

The second question eliminates options rather than adding them. If the component is a pressure boundary sized by code, compare the allowable stress of candidate grades at your design temperature rather than comparing room-temperature tensile numbers. If the part is neither loaded nor structural, strength is not a selection criterion and paying for it is waste.

• Below 345 MPa requirement — a CP grade will do; Grade 2 unless forming dictates otherwise.
• Roughly 480–550 MPa — Grade 4 or Grade 12 territory, depending on the corrosion answer above.
• Around 620 MPa with good weldability — Grade 9, particularly for tube structures.
• Above 800 MPa — Grade 5, or Grade 23 where toughness governs.

Question 3: how must it be made?

Fabrication is where otherwise sound specifications fail on the shop floor. Deep drawing and severe cold bending push towards Grade 1. Welded tube structures push towards Grade 9. Heavy machining of a high-strength alloy costs more per part than machining Grade 2, and Grade 5 machines worse than any of them.

Comparison across the grades we quote

Values are the published minimums of the referenced ASTM specification, annealed condition. They are starting points for narrowing the field, not design allowables.

Decision routes

These are the six routes that account for the great majority of enquiries we see.

1. Ambient seawater or seawater cooling → Grade 2. No reason to spend more, unless the design contains loaded parts that push strength.
2. Hot brine, evaporator or brine heater → Grade 12. Grade 2 works cooler; above roughly 70 °C with crevices it stops being the safe answer.
3. Dilute reducing acid → Grade 7. Confirm against published corrosion data for your concentration and temperature first.
4. Deep drawn or severely formed part → Grade 1. The extra ductility is the whole purpose.
5. Strength-limited machined component → Grade 5 annealed, or Grade 23 where toughness governs.
6. Welded tube structure → Grade 9. Better weldability than Grade 5 with useful strength above Grade 2.

Cost logic between grades

We do not publish prices, because titanium pricing moves with sponge costs, conversion costs and quantity, and a stale price is worse than none. The relative logic is stable, though, and worth understanding before you write a specification.

• Grade 2 is the floor. It is the highest-volume grade, needs no alloying additions and needs no heat treatment to reach specification.
• Grade 1 and Grade 4 sit close to Grade 2 with small premiums reflecting smaller campaign volumes.
• Grade 12 carries a modest premium over Grade 2, because molybdenum and nickel are cheap relative to titanium.
• Grade 7 carries a large premium because palladium is expensive, which is why it is used selectively rather than universally.
• Grade 5 costs appreciably more per kilo and appreciably more per machined part, because it cuts slower than CP titanium.
• Grade 23 costs more than Grade 5 for the extra melting and verification discipline its interstitial limits demand.

Where buyers over-specify

Three patterns account for most unnecessary spend.

• Specifying Grade 5 for corrosion duty. Grade 5 is not more corrosion resistant than Grade 2 in seawater or oxidising media. Buyers pay the alloy premium and receive no corrosion benefit.
• Using Grade 7 where the duty never becomes reducing. If the stream stays oxidising, Grade 2 performs equivalently for considerably less money.
• Calling up Grade 23 because Grade 5 was mentioned in a specification. ELI benefits are specific to toughness-critical service; elsewhere it simply costs more.

Specification template

Copy this into your enquiry. Answering these questions up front is the single biggest factor in how quickly a quotation can be prepared.

1. PRODUCT FORM:     plate / sheet / bar / tube / wire / flange /
                     forging / machined part / other: ______
2. DIMENSIONS:       ______
3. QUANTITY:         ______
4. STANDARD:         ______        REVISION: ______
5. GRADE:            ______ (or: advise)
6. CONDITION:        annealed / STA / stress relieved / as rolled
7. ENVIRONMENT:      medium ______   concentration ______
                     temperature ______ degC   crevices yes / no
8. MECHANICAL NEED:  required min yield ______ MPa  (if known)
9. FABRICATION:      welding / deep drawing / machining / bending
10. DOCUMENTS:       MTC / EN 10204 type ______ / third-party ______
11. DESTINATION:     country ______   port ______   Incoterm ______
12. REQUIRED BY:     ______

Related guides and grade pages

Frequently asked questions