2219-T851 Round Aluminum Bar Weldable Cryogenic Grade Al-Cu Alloy Aerospace

2219-T851 round aluminum bar is an age-hardenable aluminum-copper alloy engineered for service environments that defeat ordinary structural grades. The T851 temper combines solution heat treatment, controlled stretching and artificial aging to deliver a unique balance of high strength, fracture toughness and outstanding weldability. Because the alloy keeps useful mechanical properties from cryogenic temperatures down to -250°C all the way up to 315°C, it has become the standard choice for welded aerospace hardware that must survive extreme thermal cycling.

Each bar is produced under strict process control with ultrasonic inspection, and material documentation follows the full chain from ingot casting to final straightening. The result is a round bar with consistent grain flow, minimal residual stress and dependable response to subsequent machining, forming and fusion welding operations.

• Wide service temperature window: retains toughness at cryogenic levels and resists softening during sustained exposure up to 315°C, a range no 6xxx alloy can cover.
• Exceptional weldability: 2219 accepts gas tungsten arc and gas metal arc welding with matching filler, and welded joints recover high strength through post-weld aging.
• Stress corrosion resistance: the T851 temper shows superior resistance to exfoliation and stress corrosion cracking compared with other high strength 2xxx tempers.
• High fracture toughness: controlled stretch eliminates residual stresses that otherwise cause distortion during heavy machining of long components.
• Proven aerospace pedigree: widely specified for launch vehicle structures, cryogenic tankage and welded pressure vessels where reliability is non-negotiable.
• Clean machined surface: bars arrive free of laps, seams and oxide inclusions, ready for immediate CNC processing without additional conditioning.
• Full traceability: each lot carries heat number, chemical analysis and mechanical test reports that satisfy demanding customer quality systems.

2219-T851 round aluminum bar is specified for aerospace launch vehicle booster structures, cryogenic propellant tank fittings, welded pressure vessels, high speed rotating machinery and tooling that must hold dimension through temperature swings. Commercial fabricators use the grade for liquefied natural gas equipment, vacuum chamber components and structural parts for satellite ground stations. When welded assemblies must be heat treated after fabrication to restore full properties, 2219 responds predictably and does not suffer the grain growth problems seen in some alternative alloys.

We offer precision saw cutting, CNC turning and milling, centerless grinding and specialized stress relieving when deep machining is planned. Bars can be supplied with chamfered ends and protective bore caps for seamless integration into your production line. Material certificates include full chemical composition, tensile data and optional third party inspection reports.

All bars are oiled, wrapped in moisture barrier paper and secured in fumigation-free plywood export cases to protect the bright surface during ocean freight. Larger diameters are individually sleeved to prevent transit damage. Every production lot is verified through chemical analysis, tensile testing and ultrasonic inspection, and our quality system is certified to ISO 9001. Please send your required diameter, length and delivery destination so we can prepare a quotation with current lead times.