7050 aluminum
7050 plate, forging and temper distinctions, directional properties, corrosion protection and fabrication limits.
Tags: materials, aluminum, aerospace-materials
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Alloy identity and purchasing scope
Kaiser's historical table for 2.001–3.000 in 7050-T7451 plate lists longitudinal tensile/yield minima of 73/63 ksi and short-transverse minima of 68/59 ksi. The tensile difference is 5 ksi (about 34.5 MPa). Keep the original plate direction with the test and use the current ordered specification for acceptance. Kaiser historical Table 7.2
7050 is a heat-treatable wrought aluminum–zinc–magnesium–copper alloy containing zirconium. The Aluminum Association's Teal Sheets, revised December 2025, specify zinc at 5.7–6.7%, copper at 2.0–2.6%, magnesium at 1.9–2.6% and zirconium at 0.08–0.15% by mass. 7050A is separately registered; retain the suffix when assessing equivalence. Composition limits identify the alloy, not its product form, temper or qualified service. Aluminum Association, Teal Sheets, 7050/7050A entries
Smiths describes 7050 for heavy plate and aerospace structures, including T7451 and T7651 supply. Those are application and availability descriptions, not approval for an aircraft component or permission to replace 7075, 7010 or another drawing-specified alloy. Its datasheet is marked ©2023 and explicitly disclaims property guarantees. Smiths 7050 technical datasheet
Specify alloy, temper, product form, dimensions, standard/edition, test orientation, inspection requirements and surface condition. For critical parts, identify the approved material source and any supplementary toughness, corrosion or nondestructive-inspection requirements. “7050 aerospace aluminum” is an incomplete acceptance description.
Plate and forging tempers are different products
SAE AMS4201H, revised 25 February 2025, covers 7050-T7651 plate in nominal thickness 0.250–3.000 in (6.35–76.20 mm), solution treated, stress relieved and overaged. In contrast, AMS4108G, revised 20 April 2026, covers 7050-T7452 hand forgings up to 8 in (203 mm) and forging stock, with compression stress relief. The public scope records demonstrate why a plate specification cannot be assigned to a forging by alloy number alone. SAE AMS4201H; SAE AMS4108G
Otto Fuchs' AZ84/EN AW-7050 datasheet, Rev.1, separately tabulates extruded profiles/tubes/bars, die forgings and hand forgings. Its hand-forging table distinguishes longitudinal, long-transverse and short-transverse tests by thickness. It labels its information unsuitable for design use; no printed publication date is shown. Otto Fuchs AZ84 datasheet
Preserve the complete temper and manufacturing route. A different aging or stress-relief condition is not merely a spelling variation. Do not derive a shop heat-treatment recipe from the temper designation: thermal processing, quenching, residual stress and acceptance testing require a controlled product-specific procedure.
Typical mechanical values are not minima
Kaiser's 7050 Sheet Coil & Plate Technical Data, marked Rev. 05/06, explicitly labels these values typical and longitudinal:
| Temper | Ultimate tensile strength | Yield strength | Elongation over 4D |
|---|---|---|---|
| T7651 | 552 MPa | 489 MPa | 11% |
| T7451 | 524 MPa | 469 MPa | 11% |
Do not use these as guaranteed minima, fatigue limits or short-transverse properties. Kaiser 7050 technical data, p. 1
Kaiser's sheet/plate handbook instead reproduces Aluminum Standards and Data 2006 limits. For 7050-T7451 plate at 2.001–3.000 in thickness, it lists longitudinal minimum ultimate/yield of 73/63 ksi, versus 68/59 ksi short transverse. It attaches footnotes and test-direction requirements. These historical entries illustrate thickness/direction dependence; the current ordered specification governs acceptance. Kaiser sheet/plate handbook, Table 7.2, KA-SP-AA6-1.09
Define L, LT and ST relative to the actual product's working/grain directions and retain them through blank layout and machining. For a forging, grain flow and specimen location require the forging-specific definition. A plate cut into a different part orientation does not acquire new material directions based on the finished drawing axes.
Toughness, fatigue and corrosion require separate evidence
A high tensile number does not establish fracture toughness, crack-growth behavior or fatigue life. Obtain the required property type, specimen orientation, thickness, test method and acceptance basis for the product. A supplier's description of “good toughness” is not a numerical design allowable.
Kaiser rates T7451/T7651 general corrosion C, calling for protection at least on faying surfaces. Stress-corrosion rating B includes limited short-transverse laboratory failures. Neither means immunity. Kaiser 7050 comparative characteristics and footnotes
Define the actual environment, sustained stresses, grain orientation, fastener interfaces, drainage and protection system. Keep machined pockets, cut ends, holes and repair areas within the finishing plan. A temper selected for corrosion resistance still requires the specified surface treatment and inspection where the design calls for them.
Machining, residual stress and forming
KaiserSelect's aerospace-plate brochure describes improved flatness and reduced movement during machining as product-specific benefits. They are not guarantees that every 7050 plate or every deeply pocketed part will remain flat after material removal. The retrieved brochure shows no printed publication date. KaiserSelect aerospace plate brochure
Plan roughing/finishing sequence, workholding, stock allowance and intermediate inspection for the actual part. Large asymmetric removal can expose distortion that was not visible in the incoming plate. Retain the original grain orientation and traceable material identity when nesting blanks.
For forming or straightening, establish an approved condition and process window. Do not assume an overaged plate or forging can be cold bent like annealed sheet. Any proposed heating must be reviewed for final properties, distortion, corrosion behavior and certification; simply preserving the 7050 label does not preserve the original temper.
Joining and service limits
Kaiser rates gas/arc welding and brazing D for these tempers: no commonly used methods developed. Spot welding receives B, requiring special techniques or trials. Qualify any proposed joining route. Kaiser 7050 joining ratings
Treat welded repairs or a new joining route as an engineering change requiring the applicable design authority and qualification. Parent-material tensile properties do not establish joint strength. For mechanical joints, evaluate bearing, net section, fastener loads, fretting and corrosion interfaces using the governing design method.
Likewise, a room-temperature table does not establish continuous-service temperature, fire performance or cryogenic suitability. Identify the actual temperature/time history, load spectrum and environment before selecting allowables. A product advertised for aerospace use is not automatically suitable for every aerospace application.
Traceable release
Keep the material certificate, source edition, product form, temper, original dimensions, test directions and supplementary requirements linked to the finished part. Distinguish supplier typical data, specification minima, batch results and approved design values. Resolve alloy substitutions, missing orientation evidence and changes in thermal or joining route before release.