Aluminum & Aluminum Alloys•Wrought Aluminum Alloys•

VERIFIED(Source-Verified)

5251 Aluminum

Primary Designation:AA 5251

Aliases:

EN AW-5251

Mat Grades internal verification confirms source-backed fidelity and data integrity. It does not constitute external certification or guaranteed lot conformity. Read engineering disclaimer →

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Data Completeness:11 composition elements and 21 condition-specific property values cataloged.

Omitted fields represent unverified properties. "Missing is better than invented."

Key Engineering Properties

Representative source rows, qualified by their reported conditions. Inspect the tables below for all values, limits, and source notes.

Density

2.69 g/cm³TYPICAL · temperature not stated

Thermal Conductivity

149 W/(m·K)TYPICAL · temperature not stated

Composition Excerpt

Mg 1.7–2.4 wt%Magnesium (range)

Standard Elemental Basis: RANGE

Tensile Strength

160 – 200 MPaRANGE · O Temper · temperature not stated

Engineering Summary

5251 (EN AW-5251) is a medium-strength work-hardening Al-Mg alloy (2% Mg, 0.3% Mn) widely utilized across marine, transportation, and general sheet metal pressings where rapid work hardening and superior marine durability are required.

Recognized Aliases

Source-backed commercial trade name and short designations cataloged in canonical data.

EN AW-5251

5251 Aluminum Specifications & Designations

Standard Designations & Applicable Specifications — Semantically classified designations distinguishing primary standard identifiers, commercial trade names, and applicable specification references.

Direct Standard DesignationsDIRECT DESIGNATION

4 Primary Identifiers

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System	Identifier	Standard System Name	Classification Notes & Provenance
AAPRIMARY	5251	Aluminum Association	—Ref: Aalco European Standard Aluminium Alloy Technical Datasheet
UNS	A95251	Unified Numbering System	—Ref: Aalco European Standard Aluminium Alloy Technical Datasheet
EN	EN AW-5251	European Standard	—Ref: Aalco European Standard Aluminium Alloy Technical Datasheet
ISO	AlMg2	International Organization for Standardization	—Ref: Aalco European Standard Aluminium Alloy Technical Datasheet

Recognized Commercial Aliases & Trade NamesCOMMON ALIAS

1 Listed

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Recognized Name / Alias	Classification	Technical Usage & Context
EN AW-5251	Commercial Alias	Colloquial or commercial industry synonym

Applicable Specifications & Product Form ReferencesSPECIFICATION REFERENCE

2 Applicable Standards

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Standards Body	Specification Code	Specification Title / Scope	Relationship Type
CEN	EN 485-2	Aluminium and aluminium alloys - Sheet, strip and plate - Part 2: Mechanical propertiesPRODUCT_SPECIFICATION · Product form: Sheet & Plate	Specification Reference
CEN	EN 573-3	Aluminium and aluminium alloys - Chemical composition and form of wrought products - Part 3: Chemical composition and form of productsPRODUCT_SPECIFICATION	Specification Reference

Engineering Notice: Applicable specifications establish manufacturing requirements, dimensional tolerances, and test criteria for specific product forms (e.g. bus bar, wire, plate, pipe). They represent applicable technical standards, not alternative or equivalent alloy grades.

5251 Aluminum Chemical Composition

Chemical Composition (Weight %) — Elemental limits and values from the cited source. Preserves exact semantic limits (minimums, maximums, and ranges).

Scroll horizontally for full elemental limits

Element	Symbol	Semantic Basis	Specified Value	Unit	Metallurgical Notes & Qualification	Data Status
Magnesium	Mg	RANGE	1.70 – 2.40	wt%	Ref: Aalco Metals Ltd	VERIFIED
Iron	Fe	MAXIMUM	≤ 0.50	wt%	Ref: Aalco Metals Ltd	VERIFIED
Manganese	Mn	RANGE	0.10 – 0.50	wt%	Ref: Aalco Metals Ltd	VERIFIED
Silicon	Si	MAXIMUM	≤ 0.40	wt%	Ref: Aalco Metals Ltd	VERIFIED
Zinc	Zn	MAXIMUM	≤ 0.15	wt%	Ref: Aalco Metals Ltd	VERIFIED
Titanium	Ti	MAXIMUM	≤ 0.15	wt%	Ref: Aalco Metals Ltd	VERIFIED
Chromium	Cr	MAXIMUM	≤ 0.15	wt%	Ref: Aalco Metals Ltd	VERIFIED
Copper	Cu	MAXIMUM	≤ 0.15	wt%	Ref: Aalco Metals Ltd	VERIFIED
Other Elements Each	OE	EACH	≤ 0.05 each	wt%	Ref: Aalco Metals Ltd	VERIFIED
Other Elements Total	OT	TOTAL	≤ 0.15	wt%	Ref: Aalco Metals Ltd	VERIFIED
Aluminum	Al	REMAINDER	Remainder	wt%	Balance aluminumRef: Aalco Metals Ltd	VERIFIED

* Elemental percentages are expressed in weight percent (wt%). Values represent applicable specification limits. Unspecified trace elements are not fabricated or assumed.Preserves exact semantic basis

Property Display UnitsSwitch between Canonical SI and Source / US Customary units:

5251 Aluminum Physical Properties

Source-specific physical properties. Test temperatures are shown only where reported.

1 Parameters

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Property Parameter	Canonical SI Value	Semantic Basis	Test Temperature / Context Range	Source Raw Reference	Source Reference	Status
Density	2.69 g/cm³	TYPICAL		2.69 g/cm³	Aalco Metals Ltd	VERIFIED

5251 Aluminum Thermal & Thermodynamic Properties

Phase change temperatures, thermal conductivity, specific heat, mean coefficients of thermal expansion across standardized temperature ranges, and recommended thermal processing windows.

3 Parameters

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Property Parameter	Canonical SI Value	Semantic Basis	Source Raw Reference	Source Reference	Status
Coefficient of Thermal Expansion	25 µm/(m·K)	TYPICAL	25.0 µm/(m·K)	Aalco Metals Ltd	VERIFIED
Solidus Temperature	625 °C	TYPICAL	625 °C	Aalco Metals Ltd	VERIFIED
Thermal Conductivity	149 W/(m·K)	TYPICAL	149 W/(m·K)	Aalco Metals Ltd	VERIFIED

5251 Aluminum Mechanical Properties

Contextual Mechanical Properties & Tempers: Engineering strength, ductility, and hardness values grouped by product form, temper, and section thickness. Mechanical properties are contextual and not isotropic averages.

Elastic & Baseline Mechanical ConstantsSource-specific measurement conditions

Modulus of Elasticity

70 GPa

Product Form:

Temper / Condition:

Showing 8 of 8 conditions

Scroll horizontally for all conditions & tempers

Product Form	Temper / Condition	Section Size	Tensile (UTS)	Yield Strength	Elongation	Shear Strength	Fatigue Strength	Hardness (Scales Preserved)	Status
Sheet & Plate	O Temper Source values and qualifiers Yield Strength (0.2% Proof Stress): ≥ 60 MPa (MINIMUM)Aalco Metals Ltd — mat-phase4c-5251 Mechanical Properties O Sheet & Plate 0.2mm to 50.0mm Ultimate Tensile Strength: 160–200 MPa (RANGE)Aalco Metals Ltd — mat-phase4c-5251 Mechanical Properties O Sheet & Plate 0.2mm to 50.0mm Elongation (A50 mm): ≥ 22 % (MINIMUM)Aalco Metals Ltd — mat-phase4c-5251 Mechanical Properties O Sheet & Plate 0.2mm to 50.0mm O	0.2mm to 50.0mm	160–200 MPa	≥ 60 MPa	≥ 22 %	—	—	—	VERIFIED
Sheet & Plate	H22 Temper Source values and qualifiers Yield Strength (0.2% Proof Stress): ≥ 130 MPa (MINIMUM)Aalco Metals Ltd — mat-phase4c-5251 Mechanical Properties H22 Sheet & Plate 0.2mm to 25.0mm Ultimate Tensile Strength: 190–230 MPa (RANGE)Aalco Metals Ltd — mat-phase4c-5251 Mechanical Properties H22 Sheet & Plate 0.2mm to 25.0mm Elongation (A50 mm): ≥ 11 % (MINIMUM)Aalco Metals Ltd — mat-phase4c-5251 Mechanical Properties H22 Sheet & Plate 0.2mm to 25.0mm H22	0.2mm to 25.0mm	190–230 MPa	≥ 130 MPa	≥ 11 %	—	—	—	VERIFIED
Sheet & Plate	H24 Temper Source values and qualifiers Yield Strength (0.2% Proof Stress): ≥ 165 MPa (MINIMUM)Aalco Metals Ltd — mat-phase4c-5251 Mechanical Properties H24 Sheet & Plate 0.2mm to 25.0mm Ultimate Tensile Strength: 210–250 MPa (RANGE)Aalco Metals Ltd — mat-phase4c-5251 Mechanical Properties H24 Sheet & Plate 0.2mm to 25.0mm Elongation (A50 mm): ≥ 8 % (MINIMUM)Aalco Metals Ltd — mat-phase4c-5251 Mechanical Properties H24 Sheet & Plate 0.2mm to 25.0mm H24	0.2mm to 25.0mm	210–250 MPa	≥ 165 MPa	≥ 8 %	—	—	—	VERIFIED
Sheet	H26 Temper Source values and qualifiers Yield Strength (0.2% Proof Stress): ≥ 190 MPa (MINIMUM)Aalco Metals Ltd — mat-phase4c-5251 Mechanical Properties H26 Sheet 0.2mm to 6.0mm Ultimate Tensile Strength: 230–270 MPa (RANGE)Aalco Metals Ltd — mat-phase4c-5251 Mechanical Properties H26 Sheet 0.2mm to 6.0mm Elongation (A50 mm): ≥ 5 % (MINIMUM)Aalco Metals Ltd — mat-phase4c-5251 Mechanical Properties H26 Sheet 0.2mm to 6.0mm H26	0.2mm to 6.0mm	230–270 MPa	≥ 190 MPa	≥ 5 %	—	—	—	VERIFIED
Sheet & Plate	O Temper Source values and qualifiers HB Hardness: 44 HB (TYPICAL)Aalco Metals Ltd — mat-phase4c-5251 Hardness O Sheet & Plate 0.2mm to 50.0mm O	0.2mm to 50.0mm	—	—	—	—	—	44 HB	VERIFIED
Sheet & Plate	H22 Temper Source values and qualifiers HB Hardness: 56 HB (TYPICAL)Aalco Metals Ltd — mat-phase4c-5251 Hardness H22 Sheet & Plate 0.2mm to 25.0mm H22	0.2mm to 25.0mm	—	—	—	—	—	56 HB	VERIFIED
Sheet & Plate	H24 Temper Source values and qualifiers HB Hardness: 62 HB (TYPICAL)Aalco Metals Ltd — mat-phase4c-5251 Hardness H24 Sheet & Plate 0.2mm to 25.0mm H24	0.2mm to 25.0mm	—	—	—	—	—	62 HB	VERIFIED
Sheet	H26 Temper Source values and qualifiers HB Hardness: 68 HB (TYPICAL)Aalco Metals Ltd — mat-phase4c-5251 Hardness H26 Sheet 0.2mm to 6.0mm H26	0.2mm to 6.0mm	—	—	—	—	—	68 HB	VERIFIED

Hardness Integrity Notice: Rockwell B (HRB), Rockwell F (HRF), and Superficial 30T (HR30T) scales are reported on their measured scales without cross-scale mathematical conversion.

Source: See fact-level citations

Practical Engineering & Fabrication Notes

By Mat Grades Editorial Desk · Updated 2026-11-14. Use alongside the specified product standard and supplier certificate.

Machining & shop-floor behavior

For 5251 Aluminum, a qualified cutting-speed or tool-life recommendation is not supplied in the available record. A relevant hardness example is HB Hardness: 44 HB (typical; O Temper, O, Sheet & Plate, 0.2mm to 50.0mm). Use that supplied condition for a trial of the difficult feature. Record tool changes, burr removal, unclamped dimensions and accepted parts per hour. Relative machinability ratings from different reference scales should not be compared as if they were one common test.

Weldability, brazing & joining

No qualified weld procedure, filler selection or preheat/interpass schedule is established by this material record. Obtain a procedure for the actual joint, supplied condition and section rather than copying one from a nearby grade. The first cataloged strength example is Yield Strength (0.2% Proof Stress): minimum 60 MPa (minimum; O Temper, O, Sheet & Plate, 0.2mm to 50.0mm). Assess the final part after joining or thermal processing. Include distortion, cleanup and inspection in the quotation. A material designation or favorable process rating is a starting point for qualification, not evidence that an untested joint meets the drawing.

Corrosion & service environment

Review the finish, moisture traps and contact with other metals before accepting an assembly for service. Alloy, temper and surface treatment answer different questions. A stronger listed condition does not automatically solve corrosion, wear or deflection, and thermal-property data is not a maximum operating-temperature rating. The recorded thermal example is Coefficient of Thermal Expansion: 25 µm/(m·K) (typical; additional condition not stated). State the exposure and inspection access in the design record so that a change of installation or cleaning method triggers a review. The selected composition entries are Mg 1.7–2.4 wt%, Fe maximum 0.5 wt%, Mn 0.1–0.5 wt%. Chemistry documents identity; it does not establish fluid compatibility.

Selection trade-offs & applications

Use AA 5251, UNS A95251, EN EN AW-5251 to identify the candidate, then specify the product form and delivered condition separately. A specific component application is not asserted where the source record does not provide one. The listed forms include Sheet & Plate, Sheet; confirm the actual stock offered by the supplier. Compare the complete route through machining, joining, finish and inspection. Keep the certificate, required test location and acceptance criteria with the first-article record. A later change of grade, condition or source should be assessed against that same requirement.

Technical references: Aalco Metals Ltd

5xxx Series Wrought Aluminum Alloys

Wrought aluminum alloys grouped under the 5xxx metallurgical series sharing fundamental alloying systems and physical characteristics.

6 Adjacent Grades

5005

5052

5083

5251Current Grade

5251 Aluminum

5454

5754

Related Engineering & Metallurgy Guides

Contextual technical guides explaining degradation mechanisms, testing methodologies, and selection criteria relevant to 5251 Aluminum.

Welding & Fabrication18 min read

How to Weld Aluminium to Aluminium: TIG, MIG, Filler Metals & Alloy Guide

Aluminium possesses distinct physical and metallurgical properties—including a tenacious refractory oxide layer that melts at 2,072°C, thermal conductivity five times higher than structural steel, extreme liquid hydrogen solubility, and a lack of visible color change before melting. Successful aluminium-to-aluminium welding requires matching the base alloy series to an appropriate process (AC TIG, pulsed MIG, or SMAW) and compatible filler metal while designing for unavoidable heat-affected zone softening.

Author: Mat Grades Editorial DeskRead Guide →

Sources

Sources & Provenance Trail: Authoritative reference publications, standards specifications, and data registers cited across this material record.

Aalco Metals LtdAalco European Standard Aluminium Alloy Technical Datasheet

MANUFACTURER

Reviewed factual extraction from Aalco technical datasheets transcribing European standards (EN 573-3, EN 485-2, EN 755-2): mat-phase4c-5251 Chemical Composition EN 573-3. Selected facts only; no decorative text or full standards tables reproduced.