SGCC, DX51D, DC01, G90 and Z275 appear in the same purchase enquiry more often than they should, because buyers mix designation systems. DC01 is an uncoated cold-rolled steel defined in EN 10130. SGCC is a hot-dip galvanized steel defined in JIS G3302. DX51D is a hot-dip galvanized steel defined in EN 10346. This article separates the three families, explains coating designations such as G90 and Z275, and gives practical guidance for specifying thin-gauge galvanized coil from 0.2 mm to 0.3 mm.
Three designations, three standards
| Designation | Standard | Product form | Coating |
|---|---|---|---|
| DC01 | EN 10130 | Cold-rolled strip and sheet | None (uncoated) |
| SGCC | JIS G3302 | Hot-dip galvanized sheet and coil | Zinc, hot-dip |
| DX51D | EN 10346 | Hot-dip galvanized sheet and coil | Zinc, hot-dip |
| SECC | JIS G3313 | Electro-galvanized sheet and coil | Zinc, electrolytic |
SECC is often mixed into the same enquiry by mistake. It is electro-galvanized, carries a much thinner coating, and belongs to JIS G3313, not JIS G3302.
DC01 - the cold-rolled base steel (EN 10130)
DC01 is a low-carbon cold-rolled steel for general forming, bending and light stamping. The chemical maxima published for EN 10130 DC01 are carbon 0.12%, manganese 0.60%, phosphorus 0.045% and sulphur 0.045%. The mechanical envelope is yield strength 140-280 MPa, tensile strength 270-410 MPa and elongation A80 typically between 26% and 30% depending on thickness. DC01 is the designation that replaced the old German ST12 under DIN 1623, and it is still compared with CR4 in UK trade practice and with SPCC under JIS G3141, although none of these is an exact equivalent.
Within the DC family, DC04 is the deep-drawing grade: lower yield, higher elongation and better stretch-forming behaviour, selected when parts are drawn rather than merely bent. The choice between DC01 and DC04 is a formability decision, not a quality judgement.
Coating designations: G90, G60 and Z275
Two systems describe zinc coating weight, and they measure the same thing: the mass of zinc on both surfaces combined. ASTM A653 uses the letter G followed by the weight in ounces per square foot total for both surfaces. EN 10346 uses Z followed by grams per square metre total for both surfaces. One ounce per square foot equals about 305 g/m2, so G90 means 0.90 oz/ft2, which is approximately 275 g/m2 - the same coating as Z275.
| ASTM A653 | oz/ft2 (total both sides) | g/m2 (total both sides) | EN 10346 equivalent |
|---|---|---|---|
| G40 | 0.40 | 122 | Z120 |
| G60 | 0.60 | 183 | Z180 |
| G90 | 0.90 | 275 | Z275 |
Coating mass is measured by the triple-spot method and represents the minimum that must be supplied. Heavier coatings protect longer and also give better cut-edge behaviour after slitting.
Thin-gauge 0.2-0.3 mm coil
Very thin galvanized strip is used for cable trays, light profiles, stamping blanks, packaging and appliance parts. Four points matter when specifying 0.2-0.3 mm material. First, spangle: minimize or eliminate spangle (zero spangle) so that bending does not crack coarse zinc crystals. Second, tolerances: thickness tolerance follows EN 10131 for European supply or JIS for Asian contracts, and thin strip runs to the lower side of the nominal range. Third, surface treatment: specify passivation (anti-white-rust) for storage, or light oiling for short-term protection. Fourth, the coil core: thin strip must not be wound on a hard steel core, because the inner wraps will be dented; paper or composite cores are preferred.
How to write a correct specification
A complete enquiry line should state: base standard and grade (for example EN 10346 DX51D+Z or JIS G3302 SGCC), coating designation (G90 or Z275), coating type if not pure zinc (ZF minimized spangle, ZF zero spangle, AZ aluminium-zinc), surface treatment (passivation C, oiling O, or none), thickness and width with tolerances, coil inner diameter (commonly 508 mm or 610 mm), maximum coil weight, and packaging requirement such as GB/T 247 for export shipments.
Frequently Asked Questions
What is DC01 equivalent to? DC01 corresponds to material number 1.0330 in the EN system. In practice it is compared with SPCC (JIS G3141) and with CR4 in UK trade language, but the comparisons are approximate; the binding document is always the mill certificate issued to EN 10130.
Is DC01 the same as CR4? CR4 is a legacy UK designation for a similar mild cold-rolled steel. EN 10130 replaced the old national designations such as DIN 1623 ST12 and BS 1449 CR4, so DC01 is the current European way to specify the same class of material.
What is the difference between SGCC and DX51D? They are the same product type under different standards. SGCC per JIS G3302 guarantees tensile strength of at least 270 MPa but does not guarantee yield strength; DX51D per EN 10346 guarantees yield 140-300 MPa, tensile 270-500 MPa and elongation A80 of at least 22%. In European and Middle East contracts DX51D is the usual way to satisfy an SGCC requirement.
What is the difference between G90 and Z275? None in terms of coating mass: G90 is 0.90 oz/ft2 total both surfaces, which equals approximately 275 g/m2, the same as Z275. The difference is only the standard system in which the designation is written.
What is DC04 material? DC04 is the deep-drawing member of the DC family in EN 10130. It has a lower yield strength and higher elongation than DC01, and is specified for parts with demanding deformation such as drawn housings, deep panels and complex stampings.
Can 0.2 mm strip be hot-dip galvanized? Yes. 0.2 mm is within the gauge range of JIS G3302 and EN 10346 hot-dip products. For such thin strip specify minimized or zero spangle, a soft temper for bending, and a paper or composite core so the inner wraps are not dented.