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.