Aluminum 413: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

Aluminum alloy 413 is a member of the 4xxx series, a family defined by silicon as the principal alloying element. This series typically emphasizes improved fluidity, reduced melting range, and enhanced wear resistance rather than high strength through heat treatment.

413 is primarily strengthened by solid-solution effects from silicon and by work hardening; it is not a conventionally heat-treatable alloy like the 6xxx or 7xxx families. Typical alloying additions beyond silicon include controlled amounts of iron, manganese and trace elements to tailor castability, strength and machinability.

Key traits of 413 include moderate strength, good corrosion resistance in many atmospheric and mildly aggressive environments, excellent weldability and decent formability in softer tempers. These characteristics make it attractive in industries that require reliable joining and forming with reasonable mechanical performance, for example automotive secondary structures, consumer hardware, and some marine fittings.

Engineers choose 413 over other alloys when a combination of weldability, predictable thermal behavior in joining, and cost-effective manufacturing (forming, machining, welding) is needed without the expense or distortion risks associated with precipitation-hardening alloys. Its stability in the heat-affected zone and amenability to filler metallurgy often drive selection for welded assemblies and brazed components.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High	Excellent	Excellent	Fully annealed, maximum ductility for forming
H14	Moderate	Moderate	Good	Excellent	Partial work hardening, common for sheet goods
H18	High (cold-worked)	Low	Poor	Excellent	Heavily cold-worked for increased yield
T4*	Low-Moderate	Moderate	Good	Excellent	Not a conventional heat-treatment; natural temper after solution exposure in specialty variants
T5/T6/T651	Not typically applicable	N/A	Limited	Excellent	Heat-treatment designations generally not effective for 4xxx series; mechanical response limited
Custom Hx/Tx	Variable	Variable	Variable	Excellent	Many commercial lots are given proprietary tempers for extrusion or brazing needs

413 is primarily a non-heat-treatable alloy, so tempering typically refers to degrees of cold work (H numbers) and specific commercial tempers tailored to forming or machining. O and light H tempers are favored for complex forming, while higher H tempers trade formability for increased yield and stiffness.

Because silicon-rich phases can precipitate during thermal cycles, conventional T5/T6-type artificial aging offers minimal strengthening; specialized process routes (controlled cooling after solutioning or tailored thermomechanical treatments) are occasionally used but remain uncommon in general practice.

Chemical Composition

Element	% Range	Notes
Si	4.5–6.5	Principal alloying element providing reduced melting range, improved fluidity and solid-solution strengthening
Fe	0.4–1.2	Common impurity; forms intermetallics that affect casting and machinability
Mn	0.1–0.6	Helps control grain structure and can improve strength and corrosion performance
Mg	0.05–0.40	Small amounts; can influence strength and surface finish but kept low to avoid complicating weldability
Cu	0.05–0.25	Limited amounts to avoid significant loss of corrosion resistance; raises strength if present
Zn	0.05–0.30	Typically low; excessive zinc can reduce corrosion resistance
Cr	0.03–0.20	Trace additions stabilize microstructure and limit grain growth in processing
Ti	0.01–0.15	Grain refiner in castings and extrusions to improve mechanical properties
Others	0.05–0.50	Includes trace elements and impurities (V, Zr, Sr); controlled additions tailor castability and microstructure

The alloy balance is aluminum, and composition ranges above are indicative of common commercial formulations for the 4xxx-type wrought and casting alloys labeled as 413. Silicon dominates the performance envelope by lowering the melting/solidification range and increasing wear resistance. Minor elements (Mn, Cr, Ti) are introduced to control grain size, modify intermetallic morphology and improve strength or machinability without severely degrading weldability or corrosion resistance.

Mechanical Properties

In tensile behavior, 413 typically exhibits moderate ultimate tensile strength with reasonable elongation in the annealed condition and reduced ductility as cold work increases. Yield strength rises with H-tempers, while toughness and elongation decline as a trade-off. Work-hardening response is predictable and used to obtain target strength in formed or drawn components.

Hardness correlates with temper: O-tempered material shows lower Brinell or Vickers values, while H14–H18 tempering increases hardness via dislocation multiplication. Fatigue performance tends to be adequate for non-critical cyclic loads; however, stress concentrators and surface finish play outsized roles in lifetime in comparison to high-strength heat-treatable alloys. Thickness influences mechanical properties through cooling rates in casting/extrusion and the achievable cold work; thicker sections generally show lower effective strength and ductility due to coarser microstructure.

Designers should expect stress–strain curves that are smooth with moderate strain-hardening exponent values and a clear trade-off between strength and formability when moving up H-temper designations.

Property	O/Annealed	Key Temper (e.g., H14/H18)	Notes
Tensile Strength	~120–190 MPa	~180–260 MPa	Typical ranges depending on gauge, processing and exact composition
Yield Strength	~60–120 MPa	~140–220 MPa	Yield increases substantially with cold work
Elongation	~20–35%	~3–12%	Annealed exhibits high ductility; heavy work hardening reduces elongation
Hardness	~30–55 HB	~60–95 HB	Hardness rises with increasing cold work and alloying

Physical Properties

Property	Value	Notes
Density	2.65–2.70 g/cm³	Typical for aluminum alloys; varies slightly with alloying additions
Melting Range	~570–650 °C	Silicon lowers the solidus and reduces solidification range compared with pure Al
Thermal Conductivity	120–160 W/m·K	Lower than pure Al but still high; good for heat spreading applications
Electrical Conductivity	~30–45 % IACS	Reduced from commercially pure aluminum due to alloying; adequate for some conductor or bonding uses
Specific Heat	~0.88–0.92 J/g·K	Typical aluminum specific heat values used for thermal mass calculations
Thermal Expansion	22–24 µm/m·K (20–100 °C)	Similar to many wrought alloys; important for thermal cycling and dimensional control

The physical properties place 413 in the general-purpose aluminum alloy category: lightweight with high thermal conductivity relative to steels and many alloys, but reduced electrical conductivity compared with 1xxx series. Thermal behavior during welding and brazing is favorable because silicon reduces melting range and lowers susceptibility to hot cracking in many joining processes.

Designers must account for thermal expansion and conductivity when mating 413 components with dissimilar materials; the alloy’s high thermal conductivity makes it useful for heat dissipation where moderate strength is acceptable.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.3–6.0 mm	Uniform; strength varies with cold work	O, H14, H18	Widely used for formed panels and welded assemblies
Plate	6–150 mm	Lower productivity in thick sections; coarser microstructure	O, light H	Thicker plate may require special processing to control grain size
Extrusion	Profiles up to several meters	Can be produced in a range of cross-sections; strength via tempering	O, Hxx	Extrudability is good thanks to silicon; grain refinement important
Tube	OD small to large	Strength depends on wall thickness and work	O, H14	Common for structural tubing and brazed heat-exchanger headers
Bar/Rod	Diameters up to ~200 mm	Strength increases with cold drawing	O, H	Used for machined components and fasteners in non-critical applications

Sheets and thin-gage products are the most common deliverable form for 413, enabling stamping and deep-drawing operations. Plate and extrusion products require attention to thermal history; silicon-rich solidification and intermetallics can produce coarse phases in thick sections that affect toughness and machinability.

Extrusion benefits from silicon’s fluidity but often requires grain refinement (Ti, B additions) and careful cooling to achieve consistent mechanical performance along the profile.

Equivalent Grades

Standard	Grade	Region	Notes
AA	413	USA	Designation for commercial wrought 4xxx-series variant; compositions may vary among suppliers
EN AW	no direct single equivalent	Europe	No single EN AW designation maps exactly; similar behavior to EN AW-4043/4047 family in some attributes
JIS	no direct single equivalent	Japan	JIS standards do not commonly list a direct 413 equivalent; comparisons should be made by composition
GB/T	no direct single equivalent	China	Chinese standards may offer similar 4xxx compositions but direct one-to-one equivalence is uncommon

There is no universally exact cross-reference for 413 in many international standards because 4xxx family alloys are often formulated for specific applications (welding filler, brazing alloy, wrought use). When substituting, engineers should compare detailed composition and certified mechanical property tables rather than relying solely on numeric grade labels. Small compositional differences, especially in silicon and iron content, can change melting behavior and HAZ performance in welding.

Corrosion Resistance

413 displays good general atmospheric corrosion resistance similar to many 4xxx series alloys, driven by the naturally protective aluminum oxide and the relatively low levels of detrimental impurities. In moderately aggressive environments the alloy performs well, but chloride-rich marine conditions require careful design to avoid localized pitting, particularly if galvanic coupling to more noble metals occurs.

In marine applications, 413 can be used for structural fittings when corrosion allowances, coatings or sacrificial anodes are applied; its silicon content generally does not markedly reduce corrosion resistance compared with 5000-series magnesium alloys. Stress corrosion cracking susceptibility is low relative to high-strength 2xxx and 7xxx series alloys, but residual stresses and notches can produce localized failures if cyclic loads and corrosive environments coincide.

Galvanic interactions must be considered: when mated to stainless steels or copper alloys, 413 will act anodic and corrode preferentially unless electrically isolated or protected. Compared with 1xxx/3xxx work-hardened alloys, 413 trades some formability for better high-temperature stability in welded joints and improved wear resistance in contact applications.

Fabrication Properties

Weldability

413 is highly weldable with conventional fusion welding methods (TIG, MIG/GMAW) and is often selected where excellent fusion behavior and low hot-cracking tendency are required. Silicon lowers the melting range and improves fluidity of the weld pool; filler metals matched to the base alloy or the 4xxx series fillers are commonly recommended. Hot-cracking risk is low compared with high-copper or high-zinc alloys, but filler selection must consider joint service and corrosion concerns. The HAZ may experience limited softening depending on the degree of prior cold work; for structural tolerances, post-weld mechanical finishing or stress-relief may be necessary.

Machinability

Machinability of 413 is moderate and generally better than many high-silicon casting alloys; it machines cleanly in annealed and medium-H tempers when proper tooling and speeds are used. Carbide tooling is recommended for sustained production, with moderate cutting speeds and positive rake geometries to control chip formation. Silicon-rich intermetallics can produce abrasive wear on cutting edges, so tool material and coatings should be chosen to manage tool life. Surface finish and tolerance can be excellent with controlled feeds and coolant practices.

Formability

Formability is best in the O or lightly worked H-temper conditions and degrades as work-hardening increases. Bend radii of 1–2× thickness are achievable in annealed sheet for simple bends; more complex stamping or deep drawing operations require careful die design and lubrication control to avoid surface cracking from silicon-rich phases. Cold forming increases strength via strain hardening and is the normal route to achieve higher mechanical properties in formed components.

Heat Treatment Behavior

As a 4xxx-series alloy, 413 is fundamentally non-heat-treatable for conventional precipitation strengthening. Attempts at solution treatment and artificial aging produce minimal increases in strength compared with 6xxx and 7xxx alloys. When specific thermomechanical processing is applied (controlled cooling from near-solidus temperatures or specialized spray-quenching), small gains may be achieved, but these are not standard production routes.

Work hardening is the principal method to increase strength: cold rolling, drawing and bending reliably raise yield and ultimate strength, and temper selection is based on the degree of deformation. Annealing returns the alloy to O condition, restoring ductility and improving formability; typical annealing cycles are similar to those for other Al alloys but must avoid excessive grain growth by controlling temperature and time.

High-Temperature Performance

413 experiences progressive strength loss as temperature rises above approximately 100–150 °C, with practical service limits generally maintained below ~150 °C for load-bearing applications. Oxidation at elevated temperatures is limited by the protective aluminum oxide film, but prolonged exposure at higher temperatures accelerates diffusion-driven coarsening of silicon-rich particles and reduces mechanical performance.

In welded assemblies, the heat-affected zone can show localized softening and coarsening, especially in areas previously cold-worked; designers must factor HAZ strength reduction into welded-joint design. For sustained high-temperature service or cyclic thermal exposure, alloys from other series (e.g., high-strength 2xxx/7xxx with specialized heat treatments or high-temperature Al alloys) are preferable.

Applications

Industry	Example Component	Why 413 Is Used
Automotive	Secondary structural panels, welded brackets	Good weldability, reasonable strength, cost-effective forming
Marine	Brackets, rigging components	Corrosion resistance and ease of fabrication; good HAZ stability
Aerospace	Non-critical fittings, shrouds	Favorable strength-to-weight and weldability for secondary structures
Electronics	Heat spreaders, housings	Thermal conductivity and formability for chassis and enclosures
Consumer Goods	Appliance panels, frames	Balance of formability, finishability, and cost

413 is commonly specified where a mid-range mechanical property set and reliable manufacturing behavior (welding, forming) are required. Its combination of silicon-enhanced thermal and melting behavior and predictable work-hardening response makes it a versatility choice for many non-critical structural and enclosure applications.

Designers commonly exploit its weldability and machinability to simplify assembly and reduce total manufacturing steps compared with more demanding precipitation-hardening alloys.

Selection Insights

413 is a logical choice when weldability and good formability in softer tempers are prioritized over peak strength. Compared with commercially pure aluminum (1100), 413 trades some electrical conductivity and slightly reduced formability for significantly higher strength and better wear behavior; use 1100 when conductivity and corrosion resistance without strength demand are primary.

Compared with common work-hardened alloys such as 3003 and 5052, 413 typically sits slightly higher in strength for a given temper while maintaining similar or slightly lower corrosion resistance; choose 5052 for superior seawater corrosion resistance and 3003 for excellent formability if conductivity and joining are less critical. Compared with heat-treatable alloys like 6061 and 6063, 413 is preferred where welding and HAZ stability trump the need for peak precipitation-strengthened properties; 6061 will outperform in maximum strength but may require more complex thermal management during welding.

Select 413 when production processes emphasize welded assemblies, brazing, or extensive forming with a need for a moderate-strength, cost-effective alloy that tolerates thermal cycles without the distortion or HAZ embrittlement associated with some high-strength alloys.

Closing Summary

Aluminum 413 remains relevant as a practical 4xxx-series alloy that balances good weldability, sound formability in annealed conditions, and moderate mechanical strength for a wide range of industrial applications. Its silicon-driven melting and thermal characteristics simplify joining and processing, while controlled cold work enables designers to tailor strength without resorting to precipitation heat treatments. When engineering trade-offs favor manufacturability, HAZ stability and cost-effectiveness over absolute peak strength, 413 is a dependable material selection.