Comparison between cast aluminium alloy designations

EN, ISO, AA and JIS designation

EN numerical alloy designation	EN symbolic alloy designation	Corresponding ISO alloy designation	Corresponding AA alloy designation	Corresponding JIS alloy designation
EN AC-21000	EN AC-AlCu4MgTi	Al Cu4MgTi	204.0	AC1B
EN AC-21100	EN AC-Al Cu4Ti	Al Cu4Ti	–	Al-Cu4Ti
EN AC-21200	EN AC-Al Cu5MnMg	–	–	–
EN AC-41000	EN AC-Al Si2MgTi	Al Si2MgTi	–	–
EN AC-42000	EN AC-AlSi7Mg	Al Si7Mg	356.0	AC4C
EN AC-42100	EN AC-Al Si7Mg0.3	Al Si7Mg0.3	A356.0	AC4CH
EN AC-42200	EN AC-AlSi7Mg0.6	Al Si7Mg0.6	357.0	–
EN AC-43000	EN AC-Al Si10Mg(a)	Al Si10Mg	–	AC4A.Al-Si10Mg
EN AC-43100	EN AC-Al Si10Mg(b)	Al Si10Mg	–	AC4A.Al-Si10Mg
EN AC-43200	EN AC-Al Si10Mg(Cu)	Al Si10Mg(Cu)	–	–
EN AC-43300	EN AC-Al Si9Mg	Al Si9Mg	–	–
EN AC-43400	EN AC-Al Si10Mg(Fe)	Al Si10Mg(Fe)	–	ADC3
EN AC-43500	EN AC-Al Si10MnMg	–	365.0	–
EN AC-44000	EN AC-Al Si11	Al Si11	–	–
EN AC-44100	EN AC-Al Si12(b)	Al Si12(b)	B413.0	AC3A.Al-Si12
EN AC-44200	EN AC-Al Si12(a)	Al Si12(a)	–	–
EN AC-44300	EN AC-Al Si12(Fe)(a)	Al Si12(Fe)	A413.0	ADC1
EN AC-44400	EN AC-Al Si9	Al Si9	–	–
EN AC-44500	EN AC-Al Si12(Fe)(b)	–	–	–
EN AC-45000	EN AC-Al Si6Cu4	Al Si6Cu4	–	Al-Si6Cu4
EN AC-45100	EN AC-Al Si5Cu3Mg	Al Si5Cu3Mg	363.0	–
EN AC-45300	EN AC-Al Si5Cu1Mg	Al Si5Cu1Mg	355.0	AC40
EN AC-45400	EN AC-Al Si5Cu3	Al Si5Cu3	–	Al-Si5Cu3
EN AC-45500	EN AC-Al Si7Cu0.5Mg	–	–	–
EN AC-46000	EN AC-Al Si9Cu3(Fe)	Al Si9Cu3(Fe)	–	ADC10
EN AC-46100	EN AC-Al Si11Cu2(Fe)	Al Si11Cu2(Fe)	–	ADC12Z
EN AC-46200	EN AC-Al Si8Cu3	Al Si8Cu3	380.0	AC4B
EN AC-46300	EN AC-Al Si7Cu3Mg	Al Si7Cu3Mg	320.0	–
EN AC-46400	EN AC-Al Si9Cu1Mg	Al Si9Cu1Mg	–	–
EN AC-46500	EN AC-Al Si9Cu3(Fe)(Zn)	Al Si9Cu3(Fe) (Zn)	–	ADC10Z
EN AC-46600	EN AC-Al Si7Cu2	Al Si7Cu2	–	–
EN AC-47000	EN AC-Al Si12(Cu)	Al Si12(Cu)	–	Al-Si12Cu
EN AC-47100	EN AC-Al Si12Cu1(Fe)	Al Si12Cu1(Fe)	–	–
EN AC-48000	EN AC-Al Si12CuNiMg	Al Si12CuNiMg	–	AC8A
EN AC-48100	EN AC-Al Si17Cu4Mg	Al Si17Cu4Mg	8390.0	ADC14
EN AC 51100	EN AC-Al Mg3	–	–	–
EN AC-51200	EN AC-Al Mg9	Al Mg9	518.0	Al-Mg10
EN AC-51300	EN AC-Al Mg5	Al Mg5	–	ADC5, AC7A, Al-Mg6
EN AC-51400	EN AC-Al Mg5(Si)	Al Mg5(Si)	–	Al-Mg5Si1
EN AC-51500	EN AC-Al Mg5Si2Mn	–	–	–
EN AC-71100	EN AC-Al Zn10Si8Mg	Al Zn 10Si8Mg	–	–

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Hot Dip Galvanizing vs. Electrogalvanizing

(Hot Dip Galvanizing vs. Electroplating)

Feature	Hot Dip Galvanizing (ISO 1461)	Electrogalvanizing (ISO 2081 / ISO 19598)
Process	Molten Dip: Fabricated steel is dipped into a bath of molten zinc (approx. 450°C).	Electrolytic: Zinc is deposited onto the steel using an electrical current in a chemical solution.
Coating Thickness	Thick (Heavy Duty): Typically 35 µm to 85 µm (or more). Thickness is largely determined by steel thickness.	Thin (Precision): Typically 5 µm to 25 µm. Thickness is controlled by time and current, specified by the customer.
Bonding Mechanism	Metallurgical Bond: Zinc reacts with iron to form robust zinc-iron alloy layers integral to the steel.	Adhesion: The coating sits on top of the substrate. Adhesion testing is often required.
Appearance	Industrial/Matt: Can be dull grey, shiny, or spangled. Surface may be slightly uneven (“orange peel”).	Bright/Decorative: Typically bright, glossy, and very smooth. Often used where aesthetics are important.
Corrosion Protection	Very High (Long Term): Suitable for harsh outdoor environments. Life is proportional to the heavy thickness.	Moderate (Indoor/Controlled): Good for indoors or mild exposure. Relies heavily on passivation layers (chromates) for protection.
Passivation	Optional: “After-treatments” can be used to prevent wet storage stain, but are not always mandatory.	Mandatory: Almost always requires a conversion coating (passivate) and/or sealant to protect the thin zinc layer.
Suitability for Threads	Difficult: Thicker coating can jam threads. Bolts often require undersizing or centrifuging to clear threads.	Excellent: Thin, controlled coating maintains thread geometry. Ideal for fasteners (screws, nuts).
Hardness & Abrasion	High: The zinc-iron alloy layers are hard and abrasion-resistant.	Lower: Pure zinc is relatively soft; susceptible to scratching if not sealed.
Hydrogen Embrittlement	Low Risk: Generally low risk for standard structural steels. Focus is on venting cavities to prevent explosions.	High Risk: Critical for high-strength steels (≥ 1000 MPa). Requires baking (relief heat treatment) after plating.

NOTE

Electrogalvanizing is NOT “Cold Galvanizing.”

In industrial language, these terms refer to two completely different processes. Confusing them can lead to serious specification errors.

• Electrogalvanizing is an electrolytic plating process (ISO 2081 / ISO 19598).
• “Cold Galvanizing” is a slang term for Zinc-Rich Painting (often used for repair in ISO 1461).

Feature	Electrogalvanizing (Zinc Plating)	“Cold Galvanizing” (Zinc-Rich Paint)
Correct Standard	ISO 2081 or ISO 19598	ISO 1461 (Annex C)
What is it?	A factory process using electricity to deposit zinc in a chemical bath.	A manual process using a spray can, brush, or pistol to apply zinc-dust paint.
Also Known As	Zinc Plating, Electro-zinc, Zinc Electrodeposition.	Zinc Spray, Zinc Paint, Cold Galv, ZRP.
Application	Factory only (Rack or Barrel plating).	On-site repair or touch-up.
Appearance	Shiny, bright, metallic, smooth.	Matt grey, dull, paint-like texture.
Bonding	Adhesion: Zinc sits on the surface.	Mechanical: Binder sticks to the surface (like regular paint).
Primary Use	OEM Parts: Fasteners, automotive parts, small brackets.	Renovation: Repairing damaged hot dip galvanizing or welding spots.

Why the confusion?

The confusion comes from the temperature.

• Hot Dip Galvanizing happens at ~450°C (Hot).
• Electrogalvanizing happens at room temperature (Cold).
• Zinc Painting happens at room temperature (Cold).

Because both electroplating and painting happen at room temperature, non-technical staff sometimes call both “cold.” However, in professional specifications, “Cold Galvanizing” exclusively refers to Zinc-Rich Paint, never to Electroplating.

ISO 1461 vs ISO 2081 vs ISO 19598

ISO 1461 Hot dip galvanized coatings on fabricated iron and steel articles -Specifications and test methods

DIN 50979 vs ISO 19598 vs ISO 2081

ISO 19598 Designation | Metallic coatings — Electroplated coatings of zinc and zinc alloys on iron or steel with supplementary Cr(VI)-free treatment

ISO 2081 Designation | Metallic and other inorganic coatings — Electroplated coatings of zinc with supplementary treatments on iron or steel

ISO 2081 vs. ISO 19598

ISO 1461 vs ISO 2081 vs ISO 19598

Table 1: Scope and Process Overview

Feature	ISO 1461	ISO 2081	ISO 19598
Primary Process	Hot Dip Galvanizing: Dipping fabricated articles into molten zinc.	Electroplating: Electrodeposition of zinc.	Electroplating: Electrodeposition of zinc or zinc alloys.
Substrate	Fabricated iron and steel articles (including castings).	Iron or steel.	Iron or steel.
Coating Material	Molten zinc containing not more than 2% other metals.	Zinc.	Zinc OR Zinc Alloys (Zinc-Nickel, Zinc-Iron).
Key Exclusion	Does not apply to continuous sheet, wire, or automatic tube plants.	Does not apply to coatings on sheet, strip, or wire in non-fabricated form.	Not explicitly stated in Scope, but implies fabricated parts (rack/barrel).
Main Application	Heavy-duty corrosion protection (structural steel, outdoor furniture).	Protective and decorative purposes.	High-performance protection (automotive, high-stress) with strict environmental (CrVI-free) compliance.

Table 2: Coating Thickness and Designation

Feature	ISO 1461	ISO 2081	ISO 19598
Typical Thickness	Thick: Generally 35 µm to 85 µm (mean) depending on steel thickness.	Thin: Typically 5, 8, 12, or 25 µm.	Thin: Typically 5, 8, 12 µm (up to ~25 µm).
Thickness Determination	Determined by steel thickness (e.g., steel >6mm requires 85 µm coating).	Determined by purchaser specification in the designation.	Determined by purchaser specification in the designation.
Designation Format	Reference to standard (e.g., “ISO 1461”).	Format: Fe/Zn[Thick]/[Passivation]/[Sealant] (e.g., Fe/Zn12/A).	Format: Fe//[Alloy][Thick]//[Passivation]//[Sealant] (e.g., Fe//ZnNi8//Cn//TO).
Alloy Options	Zinc/Iron alloy layers form naturally during the hot dip process.	Zinc only.	Zn (Zinc), ZnFe (0.3-1.0% Fe), ZnNi (12-16% Ni).

Table 3: Supplementary Treatments (Passivation) & Environmental

Feature	ISO 1461	ISO 2081	ISO 19598
Passivation Chemistry	Not mandatory. “After-treatments” (e.g., to prevent wet storage stain) are allowed but not strictly defined by code.	Allows both Hexavalent Cr(VI) and Trivalent Cr(III) passivations, though warns of REACH bans on Cr(VI).	Strictly Cr(VI)-Free (Hexavalent chromium free) treatments only.
Treatment Codes	None specified in standard designation.	A (Clear), B (Bleached), C (Iridescent), D (Opaque), F (Black).	An (Transparent), Cn (Iridescent), Fn (Black).
Sealants	Not part of the standard designation.	Designated as T (e.g., T2 for organic sealant).	Designated as T (e.g., T2, T7 with optional integrated lubricant codes L/yL).
Hydrogen Embrittlement	Mentions venting/draining to prevent explosions. Low risk for standard steels.	Requires Stress Relief (SR) and Embrittlement Relief (ER) for steels ≥ 1000 MPa.	High Focus: Detailed diagrams on stress/material interaction. Mandatory relief for steels ≥ 1000 MPa.

Table 4: Corrosion Resistance (Salt Spray – NSS)

Feature	ISO 1461	ISO 2081	ISO 19598
Basis of Resistance	Proportional to thickness. Life often predicted in decades (20+ years) in real atmosphere.	Dependent on passivation type and thickness. Measured in hours of Salt Spray Test.	Dependent on Alloy (Ni/Fe), passivation, and thickness. Measured in hours of Salt Spray Test.
Salt Spray Criteria	Warning: Accelerated tests (Salt Spray) should not be used to predict long-term corrosion performance.	Example (Rack, Zn12, Iridescent): • White rust: 120h • Red rust: 264h.	Example (Rack, Zn12, Iridescent): • White corrosion: 120h • Red rust: 264h.
Alloy Performance (NSS)	N/A	N/A	High Performance: ZnNi (Zinc-Nickel) can achieve 720h without red rust.

ISO 1461 Hot dip galvanized coatings on fabricated iron and steel articles -Specifications and test methods

ISO 2081 Designation | Metallic and other inorganic coatings — Electroplated coatings of zinc with supplementary treatments on iron or steel

ISO 19598 Designation | Metallic coatings — Electroplated coatings of zinc and zinc alloys on iron or steel with supplementary Cr(VI)-free treatment

ISO 2081 vs. ISO 19598

ISO 1461 Hot dip galvanized coatings on fabricated iron and steel articles -Specifications and test methods.

1. Scope & Application

Category	Description
✅ Applies To	Batch Hot Dip Galvanizing of fabricated iron and steel articles (including certain castings).
❌ Excludes	Continuous sheet, wire, and woven/welded mesh.
❌ Excludes	Tube and pipe galvanized in automatic plants.
❌ Excludes	Fasteners (e.g., bolts, nuts) which have their own specific standards.

2. Key Terms & Definitions

Term	Definition
Significant Surface	The part of the article essential for serviceability or appearance (must be covered by coating).
Reference Area	An area (min. 10 cm²) where measurements are taken.
Local Thickness	The average of at least 5 magnetic measurements within one reference area.
Mean Thickness	The average of the Local Thickness values from all reference areas in the sample.

3. Visual Inspection Criteria

Inspect from a distance of not less than 1 meter.

Feature	Status	Requirement / Note
Blisters	❌ REJECT	Raised areas without solid metal beneath are not permitted.
Sharp Points	❌ REJECT	Roughness/points capable of causing injury are not permitted.
Uncoated Areas	❌ REJECT	Must be renovated (see Section 6) or re-galvanized.
Flux/Ash	❌ REJECT	Residues must be removed if they affect use or corrosion resistance.
Dark/Light Areas	✅ ACCEPT	Cellular patterns or dark grey areas are acceptable.
White Rust	✅ ACCEPT	“Wet storage stain” is acceptable if coating thickness is sufficient.
Weld Seepage	✅ ACCEPT	Staining from intermittent welds is acceptable (aesthetic only).

Note on Adhesion: Adhesion testing is not normally carried out. The coating should withstand normal handling. Tests (e.g., cutting) must be agreed upon before galvanizing.

4. Sampling & Testing Protocol

Step A: How Many Articles to Pick?

Select a random Control Sample from the inspection lot.

Lot Size (Articles)	Minimum Control Sample Size
1 to 3	All articles
4 to 500	3 articles
501 to 1,200	5 articles
1,201 to 3,200	8 articles
> 3,200	13 articles (up to 10,000)

Step B: Where to Measure?

Choose reference areas based on the size of the individual article.

Article Size (Significant Surface)	Required Reference Areas	Placement Guide
Large (> 2 m²)	At least 3	Approx. center, and ~100 mm from each end.
Medium (> 100 cm² to ≤ 2 m²)	At least 1	Representative area.
Small (≤ 100 cm²)	1	Group articles to make 10 cm² surface.

⚠️ CAUTION: Do not measure less than 10 mm from edges, flame-cut surfaces, or corners.

Step C: What If It Fails? (Re-Sampling)

If the original control sample fails thickness requirements, follow this procedure.

Step	Action	Outcome
1. Re-Sample	Take a new sample from the lot, twice the size of the original.	–
2. Test	Measure the new sample.	If Pass: Accept the whole lot.
3. Result	If the new sample fails:	If Fail: Reject non-conforming articles (or re-galvanize).

5. Coating Thickness Requirements

A. Standard Articles

Use for items not centrifuged (beams, plates, etc.).

Steel Thickness	Local Thickness (min)	Mean Thickness (min)
> 6 mm	70 µm	85 µm
> 3 mm to ≤ 6 mm	55 µm	70 µm
≥ 1.5 mm to ≤ 3 mm	45 µm	55 µm
< 1.5 mm	35 µm	45 µm
Castings > 6 mm	70 µm	80 µm
Castings ≤ 6 mm	60 µm	70 µm

B. Centrifuged Articles

Use for small parts spun to remove zinc (fasteners, washers).

Article Type	Local Thickness (min)	Mean Thickness (min)
Threads > 6 mm dia.	40 µm	50 µm
Threads ≤ 6 mm dia.	20 µm	25 µm
Other parts ≥ 3 mm	45 µm	55 µm
Other parts < 3 mm	35 µm	45 µm

6. Renovation (Repair) Rules

Strict limits apply to repairing uncoated areas.

Parameter	Limit / Requirement
Max Total Area	0.5% of the total surface area of the article.
Max Spot Size	10 cm² (if larger, re-galvanize).
Min Thickness	100 µm (unless otherwise agreed).
Approved Methods	Thermal zinc spray, zinc paste, or zinc paint (pigment ≥ 80% zinc mass).

7. Engineering & Safety Design

Topic	Requirement / Note
⚠️ Venting (Safety)	Enclosed cavities must have vent/drain holes. Risk of explosion if unvented.
Reactivity	Silicon-killed or ultra-low reactivity steels may not meet Table A thicknesses. (Use next lowest category).
Disputes	In case of dispute, the Gravimetric Method (ISO 1460) takes precedence over magnetic gauges.

ISO 1461 vs ISO 2081 vs ISO 19598

ISO 2081 Designation | Metallic and other inorganic coatings — Electroplated coatings of zinc with supplementary treatments on iron or steel

ISO 19598 Designation | Metallic coatings — Electroplated coatings of zinc and zinc alloys on iron or steel with supplementary Cr(VI)-free treatment

ISO 2081 vs. ISO 19598

DIN 50979 vs ISO 19598 vs ISO 2081

1. Designation & Syntax Comparison

This table highlights exactly how the “code string” (designation) differs on a blueprint. Note the use of double slashes // versus single slashes /.

Feature	DIN 50979	ISO 19598	ISO 2081
Standard Title	Electroplated Zn & Zn-Alloys (Cr(VI)-free)	Electroplated Zn & Zn-Alloys (Cr(VI)-free)	Electroplated Zn with supplementary treatments
Basis Metal	Fe (Iron/Steel)	Fe (Iron/Steel)	Fe (Iron/Steel)
Separator	Double Slash //	Double Slash //	Single Slash /
Alloy Support	Supports Zn, ZnFe, ZnNi	Supports Zn, ZnFe, ZnNi	Supports Zn Only
Designation Structure	Base // Coating+Thickness // Passivation // Seal	Base // Coating+Thickness // Passivation // Seal	Base / Stress Relief / Coating+Thickness / Passivation / Seal

2. Designation Examples (Real-World Scenarios)

Use this table to show your readers how to translate a requirement between standards.

Scenario	DIN 50979 Designation	ISO 19598 Designation	ISO 2081 Designation
Zinc (12µm), Iridescent Passivation	Fe//Zn12//Cn//T0	Fe//Zn12//Cn//T0	Fe/Zn12/C
Zinc (12µm), Black Passivation, Sealed	Fe//Zn12//Fn//T2	Fe//Zn12//Fn//T2	Fe/Zn12/F/T2
Zinc-Nickel (8µm), Transparent Passivation	Fe//ZnNi8//An//T0	Fe//ZnNi8//An//T0	Not Applicable (ZnNi not covered)
Zinc-Iron (8µm), Black Passivated	Fe//ZnFe8//Fn//T0	Fe//ZnFe8//Fn//T0	Not Applicable (ZnFe not covered)

3. Passivation & Sealing Codes

This table clarifies the specific naming conventions for the surface finish. ISO 19598 provides the most specific sealing codes.

Feature	DIN 50979	ISO 19598	ISO 2081
Transparent / Clear	An	An	A (Clear) or B (Bleached)
Iridescent	Cn	Cn	C
Black	Fn	Fn	F
Olive Green	Not available (implies Cr(VI))	Not available (implies Cr(VI))	D (Opaque)
No Sealer	T0	T0	Omitted from code
Generic Sealer	T2	T2	T2
Sealer w/ Lubricant	Not Defined	T2yL (with lubricant) T2nL (no lubricant)	T4 (Grease/Oil/Lube)

4. Performance Comparison (NSS Test – Red Rust)

This table shows the minimum neutral salt spray (NSS) hours required to reach basis metal corrosion (Red Rust) for Rack Plated parts.

Crucial Note: ISO 19598/DIN 50979 generally demand higher performance than ISO 2081 for the exact same coating thickness.

Coating Type (Rack Plated)	DIN 50979	ISO 19598	ISO 2081
Zinc 8µm Transparent (An/A)	48 hours	72 hours	72 hours
Zinc 12µm Transparent (An/A)	72 hours	96 hours	96 hours
Zinc 8µm Iridescent (Cn/C)	216 hours	264 hours	192 hours
Zinc 12µm Iridescent (Cn/C)	264 hours	336 hours	264 hours
Zinc-Nickel 8µm Transparent	480 hours	720 hours	N/A
Zinc-Nickel 8µm Black (Sealed)	720 hours	720 hours	N/A

5. Summary of Key Differences (For your text content)

This table summarizes the fundamental distinctions between the three standards regarding scope, permissible chemicals, and testing rigor.

Feature	DIN 50979	ISO 19598	ISO 2081
Material Scope	Covers Zinc and Zinc Alloys (ZnNi, ZnFe).	Covers Zinc and Zinc Alloys (ZnNi, ZnFe).	Covers Zinc (Zn) only.
Chromium Content	Strictly Cr(VI)-Free Only permits trivalent or chromium-free passivations.	Strictly Cr(VI)-Free Specifically designed for systems without Hexavalent Chromium.	Mixed Includes codes for both Cr(VI)-free and legacy Hexavalent Cr(VI) types (e.g., Type C, D).
Naming Convention	Uses “n” series (An, Cn, Fn) to explicitly denote Cr(VI)-free “New” systems.	Uses “n” series (An, Cn, Fn) to explicitly denote Cr(VI)-free “New” systems.	Uses Legacy single letters (A, C, F) which may or may not contain Cr(VI) depending on the type.
Testing Rigor (NSS)	High Generally requires longer salt spray hours for the same coating thickness compared to ISO 2081.	High Reflects modern passivation capabilities; requirements are often stricter than ISO 2081.	Baseline Standard requirements are generally lower (e.g., 192h vs 264h for iridescent Zn 8µm).
Status	Legacy (German) Predecessor to ISO 19598; still found on older German automotive drawings.	Current (International) The modern global standard for high-performance, eco-friendly zinc plating.	Current (International) The general default standard for commercial zinc plating.

ISO 19598 Designation | Metallic coatings — Electroplated coatings of zinc and zinc alloys on iron or steel with supplementary Cr(VI)-free treatment

ISO 2081 Designation | Metallic and other inorganic coatings — Electroplated coatings of zinc with supplementary treatments on iron or steel

ISO 2081 vs. ISO 19598