| 1. Material Selection and Performance Baseline |
| Commercially Pure Titanium Grade 1 | Maximum formability and corrosion resistance | Use for low-strength parts, chemical-service components, heat exchangers, and formed sheet parts where ductility is more important than strength. | Typical minimum tensile strength: 240 MPa Typical minimum yield strength: 170 MPa Typical minimum elongation: 24% | Material test report, heat number, chemical analysis, tensile test, and applicable product standard. |
| Commercially Pure Titanium Grade 2 | Balanced corrosion resistance, formability, and strength | Common choice for industrial hardware, fluid-handling components, and moderately loaded parts exposed to corrosive environments. | Typical minimum tensile strength: 345 MPa Typical minimum yield strength: 275 MPa Typical minimum elongation: 20% | Material test report, chemical composition, tensile test, dimensional inspection, and product-form certification. |
Titanium Grade 5 Ti-6Al-4V | High specific strength and general-purpose structural performance | Use for highly loaded machined, forged, or additively manufactured parts when higher strength is required than commercially pure grades can provide. | Typical minimum tensile strength: 895 MPa Typical minimum yield strength: 825 MPa Typical minimum elongation: 10% | Heat-treatment condition, material test report, tensile test, hardness where specified, and microstructure report when required. |
Titanium Grade 23 Ti-6Al-4V ELI | Higher fracture toughness and improved ductility | Consider for critical, cryogenic, biomedical, or fatigue-sensitive applications where reduced interstitial content is specified. | Typical minimum tensile strength: 828 MPa Typical minimum yield strength: 759 MPa Typical minimum elongation: 10% | Low-interstitial chemistry report, tensile test, microstructure, heat-treatment record, and application-specific certification. |
| Physical properties | Confirm design calculations and thermal limits | Define density, elastic modulus, coefficient of thermal expansion, thermal conductivity, operating temperature, and temperature-cycle requirements. | Titanium alloys typically have density near 4.51 g/cm³ and elastic modulus near 114 GPa. Values vary with grade, temperature, and processing condition. | Grade-specific datasheet, design allowables, laboratory test data, or applicable material specification. |
| Corrosion environment | Define the actual service media | List fluid composition, chloride content, pH, concentration, pressure, temperature, galvanic contacts, and cleaning chemicals. | Material must be compatible with the specified environment; do not approve titanium solely because it is generally corrosion resistant. | Compatibility assessment, corrosion test where necessary, and engineering approval. |
| 2. Geometry, Tolerance, and Surface Requirements |
| Part envelope and critical features | Separate critical and non-critical dimensions | Provide 3D CAD data, 2D drawings, datum structure, wall thickness, hole sizes, threads, radii, flatness, concentricity, and inspection datums. | Every dimension should have a stated tolerance or a clearly referenced general-tolerance standard. | Controlled drawing revision, CAD comparison report, and dimensional inspection report. |
| Dimensional tolerance | Match tolerance to function and process | Use tighter tolerances only on mating, sealing, bearing, or alignment features. Avoid applying unnecessarily tight tolerances to the entire part. | CNC-machined features commonly require individually defined tolerances; general tolerances should not replace functional requirements. | Coordinate-measuring-machine report, calibrated gauges, and first-article inspection. |
| Geometric dimensioning and tolerancing | Control position, orientation, form, and runout | Define datums and use GD&T for hole patterns, sealing faces, rotating interfaces, and critical alignment features. | Use ASME Y14.5 or ISO GPS practices consistently throughout the drawing. | GD&T inspection report with measurement strategy and equipment traceability. |
| Surface roughness | Specify by function rather than appearance | Define roughness for sealing surfaces, sliding surfaces, fatigue-critical areas, and cosmetic surfaces separately. | Example design targets: General machined surface: Ra 3.2 µm Precision sealing or sliding surface: typically Ra 0.8–1.6 µm, subject to design validation. | Surface-roughness measurement, visual standard, and process inspection record. |
| Surface treatment and cleanliness | Prevent contamination and unwanted reactions | Define cleaning method, passivation or chemical treatment if required, masking areas, residue limits, and packaging conditions. | No embedded ferrous contamination, visible burrs, harmful residues, oil, scale, or unapproved coating. | Cleaning certificate, contamination test where required, visual inspection, and packaging inspection. |
| 3. Manufacturing Process and Part Integrity |
| CNC machining | Control heat, burrs, and tool contamination | Define machining sequence, minimum wall thickness, tool material, coolant type, chip evacuation, deburring, and inspection points. | Prevent excessive heat tint, chatter, burr formation, distortion, and embedded contaminants. Titanium chips require controlled fire-safety handling. | Process plan, tool and coolant records, in-process inspection, final dimensional report, and surface inspection. |
| Forging | Improve directional strength and reduce material waste | Define forging temperature range, reduction or deformation requirements, grain-flow expectations, heat treatment, and final machining allowance. | Required mechanical properties, acceptable microstructure, no harmful laps, cracks, seams, or forging defects. | Forging process record, heat-treatment chart, ultrasonic inspection where specified, and material test report. |
| Sheet forming | Control springback and cracking | Define material condition, bend radius, forming direction, allowable thinning, intermediate annealing, and post-forming dimensional correction. | No cracks, splits, unacceptable wrinkling, excessive thinning, or distortion beyond drawing limits. | Forming inspection, thickness measurement, visual inspection, and material-condition certificate. |
| Additive manufacturing | Control porosity, anisotropy, and residual stress | Define powder specification, powder reuse policy, build orientation, support strategy, layer parameters, heat treatment, HIP requirements, and machining allowance. | Part density, tensile properties, surface condition, dimensional accuracy, and defect limits must be defined for the selected process and orientation. | Powder certificate, machine-build record, thermal-treatment record, CT or NDT report where required, and witness-coupon results. |
| Welding or joining | Protect the reactive titanium weld zone | Define joint design, shielding-gas purity, trailing-shield requirements, purge method, weld procedure, filler material, and operator qualification. | Acceptable weld color, penetration, geometry, porosity, cracking, and heat-affected-zone condition according to the approved procedure. | Qualified weld procedure, welder qualification, visual inspection, NDT where required, and weld-batch traceability. |
| 4. Testing, Quality, and Compliance |
| Material and product standards | Choose the governing specification by product form | Reference the applicable standard for sheet, plate, bar, billet, forgings, castings, or additive-manufactured material. | Examples include ASTM B265 for sheet and plate, ASTM B348 for bars and billets, ASTM B381 for forgings, and ASTM B367 for castings. Confirm the current revision and product applicability. | Certificate of conformance, material test report, heat or lot number, and current specification revision. |
| Mechanical testing | Verify strength in the supplied condition | Define tensile strength, yield strength, elongation, reduction of area, fatigue performance, fracture toughness, or creep requirements as applicable. | Results must meet the selected grade, product form, heat-treatment condition, and governing specification. | Laboratory test report with specimen location, orientation, test method, equipment identification, and lot traceability. |
| Non-destructive testing | Detect internal and surface discontinuities | Select visual, dye-penetrant, ultrasonic, radiographic, eddy-current, or computed-tomography inspection according to risk and geometry. | Acceptance levels must be stated; “NDT inspected” without a defined acceptance class is incomplete. | NDT procedure, inspector qualification, inspection map, equipment calibration, and signed report. |
| Traceability | Maintain part-to-material-to-process linkage | Require a unique part number, drawing revision, material heat or lot number, manufacturing batch, process records, inspection results, and shipment identification. | Traceability must remain intact from raw material receipt through final packaging. | Digital quality dossier, traveler or router, certificates, inspection records, and final release record. |
| Quality management | Assess process consistency, not only sample quality | Review documented inspection plans, calibration control, nonconformance handling, corrective action, change control, and supplier process capability. | Critical characteristics should have defined control methods, sampling plans, reaction plans, and approval requirements for process changes. | Quality-system audit, process audit, control plan, capability data, and corrective-action history. |
| Regulatory and application compliance | Match documentation to the end-use sector | Define requirements for aerospace, medical, chemical processing, marine, food-contact, or other regulated applications before quotation. | All required declarations, certificates, testing, biocompatibility or cleanliness evidence, and record-retention periods must be specified in the purchase order. | Compliance matrix, declarations, test reports, certificates, and retained manufacturing records. |
| 5. Sourcing and Commercial Definition |
| Supplier capability | Verify process ownership and equipment suitability | Ask whether the supplier performs machining, heat treatment, surface finishing, NDT, additive manufacturing, inspection, and packaging internally or through controlled subcontractors. | Supplier must demonstrate experience with the selected titanium grade, geometry, tolerance, production volume, and inspection burden. | Capability review, sample parts, process audit, equipment list, and approved-subcontractor list. |
| Prototype versus production | Use a sourcing route appropriate to volume | For prototypes, prioritize rapid CNC machining or additive manufacturing. For repeated high volume, compare machining from near-net shapes, forging, casting, or additive manufacturing. | Decision should consider total cost, material utilization, tooling, lead time, qualification effort, and repeatability. | Manufacturing feasibility review, costed process plan, pilot-lot results, and production-readiness review. |
| Quotation package | Prevent incomplete or non-comparable quotations | Include drawing revision, 3D model, material grade, product form, heat treatment, surface finish, inspection level, quantity, annual demand, packaging, delivery terms, and documentation requirements. | Quotation must clearly identify exclusions, assumptions, tooling charges, minimum order quantity, lead time, and inspection scope. | Completed request-for-quotation checklist and supplier quotation comparison matrix. |
| Cost drivers | Understand the total landed cost | Evaluate raw material utilization, buy-to-fly ratio, machining time, tool wear, scrap, inspection, heat treatment, finishing, packaging, logistics, and import duties where applicable. | Compare suppliers using an equivalent technical scope and documentation package. | Should-cost model, process-based quotation, and total-cost-of-ownership analysis. |
| Lead time and supply continuity | Reduce schedule and material-availability risk | Define prototype, first-article, production, and replenishment lead times. Identify approved material sources, safety stock, and alternate qualified processes. | Supplier must report capacity constraints, raw-material risks, planned shutdowns, and changes affecting delivery. | Capacity plan, production schedule, material-availability confirmation, and business-continuity plan. |
| Final acceptance and change control | Keep future production equivalent to the approved sample | Define first-article approval, sample retention, deviation approval, engineering-change notification, requalification triggers, and customer notification requirements. | No change to material source, process route, heat treatment, equipment, subcontractor, or inspection method without documented approval when the change can affect performance. | First-article report, deviation record, change-notification record, and requalification report. |