ASTM B863 Grade 4 Titanium Wire
- Standard: ASTM B863
- Grade: Grade 4 (Commercially Pure Titanium)
- UNS: R50700
- Supply form: Coil, spool or straight cut length
- Condition: Annealed or cold-worked, as ordered
- Diameter Range: Ø0.03–Ø7.0 mm
Customizable sizes are available, while specific product parameters should be confirmed per the applicable standard edition and order.
Product Overview
ASTM B863 Grade 4 titanium wire is an unalloyed commercially pure titanium wire product with UNS designation R50700. Grade 4 is the highest-strength of the commonly used ASTM commercially pure titanium grades, while retaining useful ductility, weldability and corrosion resistance; its formability is generally lower than Grades 1, 2 and 3. At room temperature its structure is predominantly single-phase alpha titanium. Performance is influenced by oxygen, iron, nitrogen, carbon and hydrogen content, grain size, cold reduction and final delivery condition.
Compared with Grade 3, Grade 4 permits higher oxygen and iron limits and therefore normally provides higher strength and hardness, with lower ductility and less margin for tight bending or severe forming. Grade 4 wire is used for corrosion-resistant mesh, electrochemical components, connections, fastening and coiled parts, and for filler applications when the applicable consumable specification is separately confirmed.
| Specification | Details | ||
| Industrial Standard | ASTM B863 | ||
| Grades | Gr4 | ||
| Diameter Range | Ø0.03–Ø7.0 mm | ||
| Typical Diameters | Ø0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, 1.0, 1.2, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 6.0, 7.0 mm | ||
| Supply Form | Coil / Spool or straightened and cut wire |
Grade-equivalence note: Grade 4 is sometimes informally compared with TA4 in the Chinese market. ASTM Grade 4 and Chinese GB/T grades must be certified to their own specifications and should not be declared fully equivalent without a clause-by-clause comparison.
Main Characteristics
- Highest strength among the common CP grades: Annealed Grade 4 has the highest strength of the four common ASTM commercially pure titanium grades while retaining useful ductility; tight coiling or severe forming should be confirmed by trials or procedure qualification. Cold work further raises strength and hardness while reducing ductility.
- Excellent corrosion resistance: A dense and stable titanium-oxide passive film forms naturally on the surface and can repassivate when oxygen or moisture is available.
- Low density: Approximately 4.51 g/cm³, about 60% of ordinary steel, supporting lightweight corrosion-resistant components and mesh structures.
- Good joinability: Grade 4 can be fusion welded or resistance welded using a qualified procedure, with complete inert-gas protection of hot metal and strict exclusion of oil, moisture and iron contamination.
- Good low-temperature toughness: CP titanium does not normally show the pronounced ductile-to-brittle transition associated with some steels.
- Not significantly strengthened by conventional heat treatment: Strength is controlled mainly by interstitial chemistry, grain size and cold work; annealing restores ductility and relieves drawing stress.
Chemical Composition
The following limits apply to ASTM B863 Grade 4. Values are mass percentages. Formal acceptance is governed by the contract edition and the producer’s certified report.
| Element | ASTM B863 Grade 4 requirement |
| Nitrogen, N | ≤0.05% |
| Carbon, C | ≤0.08% |
| Hydrogen, H | ≤0.015% |
| Iron, Fe | ≤0.50% |
| Oxygen, O | ≤0.40% |
| Residual elements, each | ≤0.10% |
| Residual elements, total | ≤0.40% |
| Titanium, Ti | Balance |
Technical references: ASTM B863 grade scope and TIMETAL 75A/S+D METALS Titanium Grade 4 commercially pure titanium technical data.
- Oxygen and nitrogen: Increase strength and hardness, but excessive levels reduce ductility, toughness and formability.
- Iron: Contributes to strength; excessive iron may affect microstructural uniformity and corrosion performance.
- Hydrogen: Must be strictly controlled because excessive hydrogen may form hydrides and increase embrittlement risk.
- Titanium content: ASTM uses “Titanium: Balance.” A fixed statement such as “Ti ≥99.5%” should not be used unless supported by the actual heat analysis or an additional producer guarantee.
Mechanical Properties
ASTM B863 includes tensile, elongation and hardness requirements for Grade 4 wire. Properties vary with diameter and delivery condition. Formal acceptance must therefore follow the ordered annealed or cold-worked condition, applicable size range, test method and the official tables of the specified standard edition.
| Property | Product-page technical statement | Acceptance basis |
| Tensile strength | Depends on diameter and annealed/cold-worked condition | Applicable ASTM B863 table and purchase order |
| Elongation | Depends on diameter, gauge length and condition | Applicable ASTM B863 table and purchase order |
| Hardness | The specification includes applicable requirements; one value cannot cover every condition | Applicable grade, condition and test method |
| Yield strength | Minimum values defined for annealed condition（Rp0.2≥483 MPa）; cold‑worked values vary with cold reduction & wire diameter, no universal fixed value | Specify condition, diameter and acceptance requirements in purchase order if yield strength is required |
Typical Annealed Grade 4 Properties (TIMETAL 75A reference data, NOT ASTM guaranteed acceptance values)
| Property | Typical annealed TIMETAL 75A value |
| Ultimate tensile strength | Approx. 680 MPa |
| 0.2% yield strength | Approx. 560 MPa |
| Elongation | Approx. 23% |
| Reduction of area | Approx. 46% |
Important: The values above are representative annealed Grade 4 data and are not ASTM B863 wire acceptance values. Diameter, cold reduction and final annealing materially affect strength, elongation and hardness. Quotations, contracts and MTRs should identify diameter, tolerance, condition, surface, coil weight or cut length, and inspection requirements.
HTN Supply and Quality Documentation
HTN organizes the supply of ASTM B863 Grade 4 titanium wire according to customer purchase requirements. Material is produced by qualified titanium-mill resources. Original mill test reports, heat traceability, chemistry and performance records can be supplied as agreed. HTN reviews the standard edition, heat number, documents, diameter, tolerance, delivery condition, coil weight or cut length and surface condition, and can arrange independent retesting, cut-to-length service, clean packaging and third-party inspection when required.
Typical Applications
- Corrosion-resistant mesh, filters and mist eliminators for chemical and marine service;
- electroplating racks, anode baskets, cathode assemblies and electrochemical connections;
- industrial parts requiring coiling, weaving, bending or flattening;
- corrosion-resistant tie wire, locating wire, small connectors and fastening components;
- non-contaminating mesh and components for food, pharmaceutical and high-purity-fluid equipment;
- corrosion-resistant fine-wire parts for vacuum, laboratory and instrumentation equipment;
- welding filler wire where a separate applicable consumable specification is confirmed;
- precision formed components with relatively low spring-load requirements, made to customer drawings.
Application boundary: ASTM B863 alone does not make the wire implant grade, aerospace grade or qualified welding filler. Medical, aerospace or filler-wire uses may also require ASTM F67, ISO 5832-2, AMS, AWS, customer specifications, drawings and the appropriate quality system.
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Fabrication and Machining Characteristics
Drawing and Dimensional Control
Titanium has low thermal conductivity, noticeable elastic recovery and a tendency to adhere to tooling. Clean, well-maintained dies, suitable lubrication and controlled area reductions should be used. Intermediate anneals are scheduled as needed to control diameter, roundness, surface damage and residual stress.
Cold working
Annealed Grade 4 wire has good bending, coiling and weaving capability. Cold drawing increases tensile strength and hardness but reduces ductility; the final condition should be selected for the customer's forming demand, strength and springback requirements.
Annealing and heat treatment
Annealing restores ductility, reduces drawing stress and stabilizes the structure. Actual temperature and soak time depend on wire diameter, cold reduction, furnace and qualified procedure. Vacuum or inert atmosphere helps limit oxidation and contamination.
Welding and joining
TIG/GTAW, resistance welding or another qualified method may be used. The weld pool, root and hot heat-affected zone require complete inert-gas protection. Oil, moisture, oxide and iron contamination must be removed. When the product is intended as filler wire, compliance with the applicable welding-consumable specification and the customer's procedure qualification must be confirmed separately.
Typical Physical Properties
The following are typical Grade 4 reference values near room temperature and are not mandatory lot-acceptance requirements of ASTM B863.
| Physical property | Reference value |
| Density | 4.51 g/cm³ |
| Elastic modulus | 105–120 GPa |
| Thermal conductivity | Approx. 16.95 W/(m·K) |
| Electrical resistivity | Approx. 0.60 μΩ·m |
| Mean CTE, 20–100°C | Approx. 8.6×10⁻⁶/K |
| Mean CTE, 20–300°C | Approx. 9.5×10⁻⁶/K |
| Specific heat | Approx. 0.52 kJ/(kg·K) |
| Beta transus | Approx. 950°C |
| Reference melting point of titanium | Approx. 1668°C |
| Magnetism | Essentially non-magnetic |
Physical-property references: TIMETAL 75A and S+D METALS Titanium Grade 4 commercially pure titanium technical data. Values vary with heat, temperature, orientation and processing condition.
Korrosionsbeständigkeit
Grade 4 titanium wire relies primarily on a stable passive titanium-oxide film for corrosion resistance. If slightly damaged, the film generally reforms when oxygen or moisture is available. Because fine wire and mesh have a high surface-area-to-volume ratio, crevices, deposits, contacting metals and cleaning conditions should also be considered.
Environments in Which Grade 4 Generally Performs Well
- Seawater, salt spray and humid air;
- neutral chloride and brine solutions;
- many oxidizing acid environments;
- nitric acid and some oxidizer-containing process streams;
- many organic acids and organic compounds;
- alkaline media;
- wet chlorine and hydrated halogen environments;
- many food, pharmaceutical and high-purity-water systems.
Environments Requiring Careful Evaluation
- Strong reducing acids under oxygen-starved conditions;
- hot concentrated hydrochloric or sulfuric acid;
- fluoride-containing media or hydrofluoric acid;
- tight crevices in hot concentrated chloride or sulfate solutions;
- anhydrous methanol or halide-contaminated methanol;
- red fuming nitric acid;
- molten chloride salts;
- cathodic-protection or electrochemical conditions that may promote hydrogen absorption;
- dissimilar-metal contact with an unsuitable galvanic design.
Engineering caution: Grade 4 is not immune to every corrosive environment. Fine wire and mesh may also be affected by crevices, deposits, contacting metals and cleaning residues. Evaluate crevice corrosion in hot chloride service and control hydrogen pickup during pickling, heat treatment and electrochemical use.
Typical Industry Manufacturing Route for Grade 4 Titanium Wire
- Raw-material selection and charge preparation: Select qualified titanium sponge and controlled clean revert, with particular attention to oxygen, iron, nitrogen, hydrogen and foreign contamination.
- Electrode preparation: Compact the charge into blocks and weld a consumable electrode while preventing contamination from iron particles, oil and moisture.
- Vacuum melting and ingot production: VAR is commonly used; electron-beam melting or another qualified route may also be used. Finished material must meet the specified chemistry and quality requirements.
- Ingot conditioning and breakdown: Crop unsuitable ends, remove surface defects, and forge or roll the ingot into billet or rod suitable for wire processing.
- Hot rolling to wire rod: Produce coil or smaller-diameter rod by controlled hot rolling while managing microstructural uniformity, oxidation and dimensions.
- Pickling, conditioning and multi-pass drawing: Remove scale and defects, then cold draw through successive dies. Schedule intermediate anneals according to total reduction until the target diameter is achieved.
- Intermediate and final annealing: Restore ductility, lower residual stress and obtain the ordered annealed condition. For cold-worked supply, final reduction is controlled to achieve the required strength and hardness.
- Surface finishing: Pickling, mechanical cleaning, polishing or another approved cleaning method may be used. Pickling and heat treatment must control hydrogen pickup, oxidation and foreign contamination.
- Straightening, coiling and cutting: Supply on coils or spools, or as straight cut lengths, and inspect diameter, roundness, straightness of cut lengths, coil quality and surface condition.
- Inspection and traceability: Verify chemistry, tensile properties, elongation, hardness, dimensions and surface quality, maintaining traceability from heat and lot to spool or package and material-test documentation.
Melting and inspection note: ASTM B863 requires finished wire to meet applicable chemistry, performance, dimensional and quality requirements. It does not prescribe the same number of VAR melts for every Grade 4 product. Double or triple VAR, tight roundness, special roughness, cleanliness, nondestructive testing, EN 10204 3.1 documentation and third-party inspection must be confirmed in the purchase order when required.
