Aluminum 1230: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

Alloy 1230 sits within the 1xxx series of aluminum alloys, classed as a commercially pure or high-purity aluminum grade. The 1xxx series is defined by aluminum content typically in excess of 99%, with very low intentional alloying additions; 1230 is characterized by a guaranteed minimum aluminum content on the order of 99.3% or higher, placing it firmly in the “purity” family rather than the structural heat-treatable families (2xxx, 6xxx, 7xxx).

Major alloying elements in 1230 are present only as controlled impurities or micro-alloying additions: iron, silicon, titanium and trace copper, manganese, magnesium and zinc at very low concentrations. Because of this chemistry, the primary strengthening mechanism for 1230 is strain hardening (cold work); it is a non-heat-treatable alloy and gains mechanical strength primarily through work-hardening and controlled mechanical processing.

Key traits of 1230 are excellent electrical and thermal conductivity, superior atmospheric corrosion resistance, very good formability in annealed conditions and excellent weldability. Its strength is low relative to engineered aluminum alloys, but it offers excellent ductility and surface finish, making it a common selection where conductivity, corrosion resistance, or deep draw formability are prioritized.

Typical industries using 1230 include electrical conductors and busbars, deep-drawn components, chemical and food handling equipment where corrosion resistance and purity matter, and decorative architectural applications. Engineers choose 1230 over other alloys when high conductivity, superior corrosion performance and forming behavior outweigh the need for elevated yield strength or peak heat-treated strengths.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High (30–45%)	Excellent	Excellent	Fully annealed, maximum ductility and conductivity
H12	Low-Medium	Moderate (20–30%)	Very Good	Excellent	Quarter-hard, moderate strength increase with retained formability
H14	Medium	Moderate-Low (10–20%)	Good	Excellent	Half-hard, common compromise between formability and strength
H16	Medium-High	Lower (6–15%)	Fair	Excellent	Three-quarter hard, used for stiffer parts with reduced forming range
H18	High	Low (3–8%)	Limited	Excellent	Full-hard, highest cold-work strength, limited formability
T5 / T6 / T651	N/A	N/A	N/A	N/A	Not applicable — 1230 is non-heat-treatable; T tempers are not used

Temper has a pronounced influence on 1230’s mechanical and physical behavior. The annealed O temper maximizes ductility, surface finish and conductivity, which makes it ideal for deep drawing and electrical applications; progressive H tempers increase strength by strain hardening while reducing elongation and forming range.

Selecting a temper is a tradeoff between forming capability and final stiffness: designers planning significant cold forming will typically specify O or H12, while components needing dimensional stability or springiness may be supplied in H14–H18. Welding and brazing operations generally do not degrade conductivity in the way heat treatment would, but welded joints may locally anneal cold-worked temper and reduce strength adjacent to the weld.

Chemical Composition

Element	% Range	Notes
Si	≤ 0.25	Residual silicon; influences fluidity in casting and minor strength
Fe	≤ 0.50	Primary impurity; increases strength slightly but can reduce ductility
Mn	≤ 0.05	Usually very low; minimal strengthening influence
Mg	≤ 0.05	Minimal; not used for age hardening in this grade
Cu	≤ 0.05	Kept low to preserve corrosion resistance and conductivity
Zn	≤ 0.10	Very low; excessive zinc can reduce corrosion resistance
Cr	≤ 0.05	Trace levels sometimes present; controls grain structure slightly
Ti	≤ 0.03	Used as a grain refiner in some production routes
Others (each)	≤ 0.05	Includes residuals such as Ni, Pb, Sn; total others controlled tightly

The balance of 1230 is aluminum (Al) with a typical minimum aluminum content of approximately 99.30% by weight; the intentionally low alloying content preserves conductivity and corrosion resistance. Trace elements such as iron and silicon are the primary contributors to the modest mechanical strength; titanium and chromium at trace levels are used to refine grain structure and to aid processing, particularly in cast or recrystallized product forms.

Small variations in impurity levels impact key performance axes: higher iron raises strength and lowers ductility and surface quality, while copper and zinc, even in small amounts, can reduce corrosion resistance. For electrical and chemical applications, the tight control of residual elements is often a procurement requirement.

Mechanical Properties

In tensile behavior, annealed 1230 displays low yield and tensile strengths with high uniform elongation, producing predictable necking and good energy absorption during forming. As cold work increases (H tempers), tensile and yield strengths rise while ductility falls; work hardening behavior is linear for moderate strain ranges and leads to stable strain aging-free response because interstitial and precipitate hardening are minimal.

Yield strength in O temper is relatively low and sensitive to minor compositional variations and thickness; thin gauges often show higher apparent yield due to processing effects and skin-hardened surfaces. Hardness in 1230 correlates closely with temper level: O condition yields low Brinell/Vickers numbers, while H14–H18 see progressive increases consistent with strain-hardening curves.

Fatigue resistance is moderate and influenced strongly by surface finish and residual stresses introduced during cold work or forming. Thin-sheet fatigue life is generally favorable for non-stressed components but designers should account for reduced fatigue limit relative to higher-strength aluminum alloys when cyclic loading is significant.

Property	O/Annealed	Key Temper (H14)	Notes
Tensile Strength	70–95 MPa	120–155 MPa	Values depend on thickness and degree of cold work
Yield Strength	25–50 MPa	90–130 MPa	Defined by offset method; annealed yield low and variable
Elongation	30–45%	10–18%	Annealed shows excellent elongation; cold work reduces ductility
Hardness (HB)	15–25 HB	30–50 HB	Hardness rises with strain hardening; indicative of work-hardening

Physical Properties

Property	Value	Notes
Density	2.70 g/cm³	Standard for most aluminum alloys; useful for mass and stiffness calculations
Melting Range	~650–660 °C	Solidus/liquidus close to pure aluminum; casting behavior influenced by impurities
Thermal Conductivity	220–240 W/m·K	High conductivity typical of high-purity aluminum; excellent for heat-exchange applications
Electrical Conductivity	58–63 % IACS	High electrical conductivity compared with alloyed series; ideal for conductors and busbars
Specific Heat	0.897 J/g·K (897 J/kg·K)	Useful in transient thermal calculations and heat-capacity design
Thermal Expansion	23.6 µm/m·K (20–25 range)	Comparable to other Al grades; important for joint design with dissimilar materials

The high thermal and electrical conductivities make 1230 a preferred choice for heat sinks, electrical conductors and thermal management hardware. The standard aluminum density produces favorable strength-to-weight and stiffness-to-weight ratios for non-structural components, although design must account for the limited high-temperature strength retention compared to alloyed series.

Thermal expansion is similar to other aluminum grades and is an important design parameter where 1230 is joined to steel or composites; differential expansion can drive stress concentrations and must be accounted for in bolted or welded assemblies.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.1–6.0 mm	Consistent through-thickness when rolled; thin gauges can be skin-hardened	O, H12, H14	Used for packaging, deep drawing, electrical panels
Plate	6–50 mm	Low absolute strength but uniform ductility in annealed state	O, H18	Plate usage is limited for structural loading unless cold-worked
Extrusion	Profiles up to several meters	Extruded properties influenced by billet temper and foram	O, H14	Complex profiles for conductor rails, architectural trims
Tube	OD 6–200 mm	Welded or seamless; wall thickness affects mechanical stability	O, H12	Conduit, heat exchangers, fluid transport in corrosive environments
Bar/Rod	2–100 mm dia	Good machinability in annealed; cold-drawn for higher strength	O, H14	Fasteners, standoffs, machined components requiring high purity

Processing differences between product forms arise from the way cold work and thermal cycles change microstructure. Sheet and extrusions are typically produced by rolling and extrusion processes that can impart preferred crystallographic textures; plate and bar may be produced from cast billets followed by rolling or drawing, with different levels of residual stress and grain size.

Applications follow form: thin sheet is dominant for deep drawing and cladding, extrusions for complex cross-sections requiring good conductivity, and bar/rod for precision machined components. Selection of form and temper should consider downstream operations such as bending, welding and surface finishing.

Equivalent Grades

Standard	Grade	Region	Notes
AA	1230	USA	Less-common proprietary or specialty designation within the 1xxx family; often specified for high-purity needs
EN AW	1050A	Europe	Closest widespread European equivalent in purity and performance; common commercial-purity grade
JIS	A1050	Japan	Typical Japanese equivalent for high-purity aluminum with similar electrical and corrosion properties
GB/T	1xxx series (e.g., 1230 in local standards)	China	Chinese standards include a family of high-purity alloys; local grade names may align with 1230 chemistry

Direct one-to-one equivalence is rare because 1230 can be a proprietary or trade designation that specifies tighter impurity controls than the generic 1050 family. European EN AW-1050A and JIS A1050 are commonly used interchangeably for many applications, but customers should verify conductivity, impurity limits and mechanical tolerances when substituting.

When cross-referencing, pay attention to guaranteed minimum Al content, maximum Fe/Si levels, and any requirements for grain refinement (Ti) or surface finish that can affect forming and electrical performance. Certificates and mill test reports are essential to confirm equivalence for critical electrical or hygienic applications.

Corrosion Resistance

1230 exhibits excellent atmospheric corrosion resistance due to its high purity and the formation of a stable, adherent aluminum oxide film. In general environments it resists pitting and uniform corrosion better than many alloyed series because active elements such as copper and zinc are minimized, making it suitable for indoor architectural applications and chemical handling where mild exposure is present.

In marine settings 1230 performs well against uniform corrosion, but chloride-induced pitting can occur in stagnant crevices or under deposits; protective coatings or anodizing are often used for long-term marine service. Stress corrosion cracking (SCC) is uncommon for 1xxx alloys because they lack the high-strength microstructures and residual tensile stresses that promote SCC in some stronger aluminum alloys.

Galvanic interactions place 1230 as the anodic partner relative to most steels, stainless steels (depending on environment), copper and brass; therefore isolation or sacrificial design is necessary when coupling with dissimilar metals. Compared with 5xxx (Mg-bearing) and 6xxx (Mg + Si) families, 1230 sacrifices strength for superior general corrosion resistance and conductivity but in highly aggressive chloride environments 5xxx alloys with proper treatment may be preferred.

Fabrication Properties

Weldability

1230 is readily welded by common fusion processes (TIG, MIG, and resistance welding) with excellent wetting and low hot-cracking tendency due to its simple microstructure and low alloy content. Filler materials are generally the same composition (e.g., pure Al filler such as ER1100/ER1050) to preserve conductivity and corrosion behavior; filler choice should consider joint conductivity needs. Weld heat-affected zones locally anneal cold-worked tempers and reduce strength adjacent to welds, so post-weld mechanical design must account for softened regions.

Machinability

Machinability of 1230 is moderate to good, comparable to other commercially pure aluminums; the alloy machines well in annealed condition but can become gummy in higher H tempers. Carbide tooling with positive rake and high coolant flow is recommended; cutting speeds are conservative compared with steels but higher than copper. Chip formation tends to be continuous and ductile; chip breakers or segmented tooling geometries help avoid entanglement and improve surface finish.

Formability

Formability is excellent in O temper and remains good in mild H tempers; 1230 supports deep drawing, spinning, and complex bending when supplied annealed. Minimum recommended inside bend radii for rolled sheet in O condition are typically in the range of 0.5–1.0× material thickness for mild bends, increasing for sharper radii or thicker stock. Cold working increases springback and reduces allowable bend radii, so process planning should specify temper and allow for springback compensation.

Heat Treatment Behavior

As a non-heat-treatable alloy, 1230 does not respond to solution treatment and artificial aging for strength increases; the principal microstructural control is via hot working and mechanical strain. Full annealing (to obtain O temper) is performed by heating into the range of roughly 350–415 °C followed by controlled cooling to achieve recrystallization and the soft ductile state; specific annealing schedules depend on gauge and prior cold work history.

Work hardening is the principal strengthening route: straining produces an increase in dislocation density and concomitant increases in yield and tensile strength. Reversing cold work by annealing returns the alloy to a low-strength, high-ductility condition and restores conductivity. T-tempers (artificial aging) are not applicable and are typically omitted from specifications for 1230.

High-Temperature Performance

1230’s mechanical properties degrade progressively with temperature; significant strength loss occurs above about 100–150 °C and its usable static strength at elevated temperatures is much lower than that of heat-treatable alloys. Continuous-service temperatures are commonly limited to below ~100 °C for load-bearing components, while short-term excursions to ~150–200 °C are possible but will accelerate softening and reduce fatigue life.

Oxidation of aluminum in air is self-limiting due to the formation of a thin protective oxide layer; high-temperature scaling is not a primary failure mode for 1230 in typical service. Heat-affected zones near welds or locally annealed regions will show reduced strength at elevated temperatures and designers should allow for creep or relaxation when operating near the material’s thermal limits.

Applications

Industry	Example Component	Why 1230 Is Used
Automotive	Interior trim panels and decorative moldings	Excellent formability and surface finish with low cost
Marine	Non-structural fittings and cable trays	Good general corrosion resistance and ease of fabrication
Aerospace	Ground support equipment and electrical busbars	High conductivity combined with acceptable mechanical behavior
Electronics	Heat sinks and electrical conductors	High thermal and electrical conductivity and purity
Food & Beverage	Tanks, piping linings, and utensils	High corrosion resistance and cleanliness; easy to sanitize

1230 is frequently specified where electrical or thermal conductivity, corrosion resistance, and forming capability are the primary functional requirements. Its relative low cost and ease of processing make it a practical choice for large-area sheet applications, conductor systems, and non-structural components where high alloy strength is not mandatory.

Selection Insights

For an engineer choosing between high-purity aluminum options, 1230 is best selected when electrical or thermal conductivity and deep formability are prioritized above high structural strength. Compared with commercially pure aluminum like 1100, 1230 trades only marginally in conductivity and formability while potentially offering tighter impurity limits or mill-controlled properties for specific applications.

Against common work-hardened alloys such as 3003 or 5052, 1230 sits lower on strength but superior in conductivity and general corrosion resistance; choose 1230 when conductivity and surface quality matter more than yield strength. Versus heat-treatable alloys like 6061 or 6063, 1230 is chosen when the design values require excellent conductivity and forming at the expense of peak achievable strength — it is preferred for conductors, deep-drawn parts, and chemically sensitive environments.

Practical selection tips: specify O temper for deep drawing or maximum conductivity, choose H14–H18 only when cold-forming can achieve the needed stiffness, and confirm mill test reports for residual element limits when used in electrical or hygienic service. Consider anodizing or coatings for marine exposure and isolate dissimilar metal contacts to prevent galvanic corrosion.

Closing Summary

Aluminum 1230 remains relevant for engineers where the combination of very high purity, superior electrical and thermal conductivity, outstanding formability and excellent corrosion resistance outweighs the need for high strength. Its predictable work-hardening response and broad availability in sheet, extrusion and bar forms make it a practical material for electrical, thermal, architectural and hygienic applications where surface finish and service environment are critical.