ASTM B348 Grade 12 Titanium Rod / Bar
- Standard: ASTM B348
- Grade: Grade 12
- Material type: Ti-0.3Mo-0.8Ni near-alpha titanium alloy
- UNS: R53400
- Room-temperature structure: Typical near-alpha microstructure, predominantly alpha
- Condition: Annealed
- Dia: φ7 ~ φ300 mm
- Typical Industrial Bar Length: 200–3000 mm
Customizable sizes are available, while specific product parameters should be confirmed per the applicable standard edition and order.
Product Overview
ASTM B348 Grade 12 titanium rod/bar is a Ti-0.3Mo-0.8Ni near-alpha titanium alloy bar produced and tested to ASTM B348/B348M. The alloy is UNS R53400, with 0.20% to 0.40% molybdenum and 0.60% to 0.90% nickel. Its room-temperature microstructure is predominantly alpha with a limited beta phase fraction.
Compared with commercially pure Grade 2, Grade 12 offers higher strength and improved corrosion performance in selected oxidizing-to-mildly-reducing, chloride-brine and crevice conditions. It is commonly supplied annealed and is selected for long-term corrosion reliability, weldability and pressure-equipment applications. Formal acceptance shall follow the contract edition, condition, dimensions and supplementary requirements.
Grade 12 bar is suitable for chemical-process reactors and internals, heat-exchanger components, pumps, valves, flanges, fasteners, seawater and brine-system hardware, hydrometallurgical equipment, flue-gas-desulfurization equipment and corrosion-critical machined components in energy, marine and oil-and-gas service.
| Specification | Details |
| Industrial Standard | ASTM B348 |
| Industrial Grades | Gr12 |
| Diameter Range | Ø7 – Ø300 mm |
| Typical Diameters | Ø7, 8, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 120, 150, 200 mm |
| Typical Industrial Bar Length | 200–3000 mm; cut-to-length available |
| Surface / Supply Condition | Hot-rolled black surface / Turned / Ground |
| Precision Tolerance | h6 / h7 / h8 available subject to diameter, finishing process and order confirmation |
Main Characteristics
- Enhanced crevice-corrosion resistance: Molybdenum and nickel improve corrosion stability in selected oxidizing-to-mildly-reducing, chloride-brine and hot-brine duties. Actual suitability must be verified for the service environment.
- Higher strength than Grade 2: Annealed ASTM minimum tensile strength is 483 MPa, minimum 0.2% offset yield strength is 345 MPa and minimum elongation is 18%.
- Good weldability: TIG, MIG, plasma, laser and electron-beam welding may be used with complete high-purity inert-gas shielding of the weld pool, face, root and hot heat-affected zone.
- Good cold and hot workability: The alloy can be forged, hot rolled, drawn, turned, milled, drilled, ground, bent and stamped. Complex cold forming must be qualified for bend radius, surface condition and intermediate annealing.
- Low density and essentially non-magnetic behavior: Density is about 4.51 g/cm³, supporting corrosion-resistant lightweight equipment and some magnetic-response-sensitive uses.
- Not principally heat-treat strengthened: Grade 12 is a near-alpha titanium alloy. Annealing stabilizes microstructure, relieves stress and supports fabrication; special thermal conditions must be stated in the order and validated by an approved process.
Chemical Composition
ASTM B348 Grade 12 chemistry is controlled to the following mass-percent limits:
| Element | ASTM B348 Grade 12 requirement |
| Nitrogen, N | ≤0.030% |
| Carbon, C | ≤0.080% |
| Hydrogen, H | ≤0.015% |
| Iron, Fe | ≤0.300% |
| Oxygen, O | ≤0.250% |
| Molybdenum, Mo | 0.20%–0.40% |
| Nickel, Ni | 0.60%–0.90% |
| Residual elements, each | ≤0.100% |
| Residual elements, total | ≤0.400% |
- Molybdenum and nickel are the defining alloying elements. Their controlled addition supports corrosion performance in designated chloride, hot-brine and mildly reducing environments.
- Oxygen, nitrogen, carbon, hydrogen and iron must be controlled. Oxygen, nitrogen and carbon can increase strength while reducing ductility; excessive hydrogen can form brittle hydrides and raise embrittlement risk.
- Final chemistry shall be confirmed by the original mill test report for the applicable heat. Any more-stringent drawing, NACE, ASME, ASTM B265/B338/B861 or customer requirement must be stated in the order.
Mechanical Requirements
The following room-temperature tensile requirements apply to annealed ASTM B348 Grade 12 bar. The specified edition, dimensions, specimen form and test orientation must also be considered for formal acceptance.
| Property | Requirement | Status |
| Ultimate tensile strength, Rm | ≥483 MPa | ASTM minimum |
| 0.2% offset yield strength, Rp0.2 | ≥345 MPa | ASTM minimum |
| Elongation in the specified gauge length | ≥18% | ASTM minimum |
| Reduction of area, Z | ≥25% | ASTM minimum |
Typical room-temperature properties (not guaranteed)
| Property | Reference Value |
| Ultimate tensile strength | Approx. 483–620 MPa |
| 0.2% offset yield strength | Approx. 345–483 MPa |
| Elongation | Approx. 18–30% |
| Reduction of area | Generally not less than 25% |
| Elastic modulus | Approx. 103–105 GPa |
Important: Typical values are not ASTM acceptance values and are not automatically guaranteed for every lot. Hardness, UT, PMI, microstructure, corrosion testing, NACE or other tests must be ordered when required.
HTN Supply and Quality Services
ASTM B348 Grade 12 titanium bar is produced by evaluated, qualified mill resources. HTN confirms technical requirements from customer drawings and purchase specifications, selects a mill with appropriate capability, reviews the original MTR and heat/lot records, and verifies the relationship among material standard, dimensions, quantity, condition and inspection documents.
When agreed in the contract, HTN can coordinate independent retesting, ultrasonic examination, PMI, cut-to-length service, turning or grinding, EN 10204 3.1 documentation and third-party inspection, together with export packing, shipping documents and international delivery.
Typical Applications
- Chemical-process reactors, vessels, agitators, tower internals and corrosion-resistant machined components;
- Heat exchangers, condensers, evaporators, seawater and brine heat-transfer-system components;
- Pump shafts, valve stems, valves, flanges, fasteners and pressure-equipment parts;
- Desalination, marine engineering, shipboard, hydrometallurgical, energy and oil-and-gas equipment;
- Flue-gas desulfurization, pollution control and other chloride-bearing or mildly reducing wet-process systems;
- Custom engineering parts requiring weldability, low weight and an improved margin against crevice corrosion.
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Fabrication and Processing Characteristics
Machining
Grade 12 can be turned, milled, drilled, ground and threaded. Titanium’s relatively low thermal conductivity, elastic recovery and tendency to gall call for sharp rigid tooling, stable feed, appropriate cutting speed and abundant non-chlorinated cutting fluid. Dwell and rubbing should be avoided.
Cold forming
Its room-temperature forming latitude is generally close to Grade 2 and it can be bent, stamped, drawn and spun. Complex or tight-radius shapes should be validated by trial or qualified procedure, using staged forming, intermediate annealing or warm forming when needed.
Hot working and heat treatment
Hot forging, rolling, extrusion and drawing can be used to produce bar. Working temperature, reduction, soak time, cooling path and atmosphere must follow a qualified process to limit grain coarsening, oxidation and alpha case. Annealing stabilizes microstructure and properties and supports the required strength-ductility balance.
Welding
Grade 12 has good weldability. The weld pool, face, root and hot heat-affected zone require complete high-purity inert-gas shielding. Critical weldments should be qualified for joint strength, ductility, corrosion behavior and any required post-weld treatment.
Machining safety: Fine titanium chips and powders are combustible and must be collected, stored and handled away from ignition sources under applicable safety requirements.
Typical Physical Properties
The following are typical reference values near room temperature and are not mandatory lot-acceptance requirements of ASTM B348:
| Physical property | Typical value |
| Density | Approx. 4.51 g/cm³ |
| Elastic modulus | Approx. 103–105 GPa |
| Specific heat at room temperature | Approx. 0.52 J/(g·K) |
| Thermal conductivity | Approx. 15–17 W/(m·K) |
| Electrical resistivity | Approx. 0.56–0.60 μΩ·m |
| Mean CTE, 20–100°C | Approx. 8.8–9.2×10⁻⁶/K |
| Beta transus | Approx. 875–905°C |
| Melting temperature | Approx. 1660–1670°C |
| Poisson’s ratio | Approx. 0.34 |
| Magnetism | Generally regarded as non-magnetic |
Physical-property references: public Grade 12 technical data and industry data. Values vary with temperature, heat, orientation, section size and annealed condition.
Corrosion Resistance
Grade 12 corrosion resistance is based on a continuous, tightly adherent titanium-oxide passive film. Molybdenum and nickel improve titanium’s behavior in selected oxidizing-to-mildly-reducing, chloride-brine and crevice conditions, giving Grade 12 a higher crevice-corrosion margin than Grade 2. Actual material selection must still be verified against medium, temperature, concentration, oxygen availability, flow and crevice conditions.
Environments in Which Grade 12 Generally Performs Well
- Natural seawater, marine atmospheres, salt spray, brines and many high-chloride aqueous media;
- many neutral aqueous solutions, general industrial water, desalination and applicable heat-transfer service;
- nitric acid and many oxidizing acidic environments;
- evaluated mildly reducing-acid, hot-brine and chloride-bearing aqueous duties;
- wet-process metallurgy, chemical processing, pollution control, energy, marine and oil-and-gas systems demanding improved crevice-corrosion resistance.
Environments Requiring Careful Evaluation
- Fluoride-bearing media or hydrofluoric acid;
- hot, concentrated, oxygen-starved or strongly corrosive acids containing reducing metal ions;
- completely dry chlorine, anhydrous methanol or halide-contaminated methanol;
- red fuming nitric acid, molten chloride salts, liquid mercury, cadmium and other special chemical environments;
- pickling, cathodic protection or electrochemical conditions that may promote hydrogen pickup;
- hot crevices, deposits, dissimilar-metal contact and stressed locations.
Engineering caution: Molybdenum and nickel improve the corrosion margin but do not make Grade 12 universally suitable for all acids, halides or oxygen-starved media. Product literature cannot replace actual-service corrosion testing and engineering review.
Typical Production Process for Grade 12 Titanium Rod
- Raw-material and alloying preparation: Select qualified titanium sponge, molybdenum and nickel addition materials and approved clean revert, while controlling oxygen, nitrogen, carbon, hydrogen, iron and foreign contamination.
- Electrode preparation: Compact the charge into electrode blocks and assemble the melting electrode, ensuring uniform molybdenum and nickel distribution and exclusion of oil, moisture and iron-bearing foreign matter.
- Vacuum melting and ingot production: Use VAR, electron-beam cold-hearth melting or another approved titanium melting route. The melting route and number of melts follow the qualified mill process and purchase requirements.
- Ingot conditioning and chemistry: Crop, peel or grind as necessary, complete required chemical analysis, retain heat identification and perform necessary internal-quality controls.
- Breakdown forging: Upset, draw or multi-directionally forge to break down the cast structure, improve internal uniformity and produce billet for further working.
- Alpha/near-beta hot working and bar formation: Forge, hot roll, extrude, draw or combine processes to produce the required section, controlling temperature, reduction and cooling path for a stable near-alpha microstructure.
- Annealing: Anneal under a qualified procedure to stabilize microstructure, relieve stress and obtain the required strength-ductility balance.
- Surface conditioning, straightening and finishing: Turn, grind, blast, pickle, straighten, cut, chamfer or polish as required. Pickling must limit hydrogen pickup and meet surface-quality requirements.
- Final inspection, documentation and delivery: Verify chemistry, tensile properties, dimensions, tolerances, surface and identification. UT, PMI, microstructure, hardness, corrosion tests or third-party inspection are performed when ordered. Maintain full correlation among material, labels, heat, lot, condition and original MTR.
