Standards

Baoshan Steel Standard
Q/BQB420
BJZ421

JIS
Japan Industrial Standard

BS2989
UK Industrial Standard

Notes

Product steel number

St01Z,St01ZR

SGCC

Z1Grade

Ordinary commercial quality

St02Z,St02ZR

Z2Grade

Mechanical Seam Quality

St03Z

SGCD1

Z3Grade

Drawing Quality

St04Z

SGCD2

Z4Grade

Deep Drawing Quality

St05Z

SGCD3

Z5Grade

Deep Drawing Quality

StE280-2Z

SGC340

Z25Grade

For structure use

StE345-2Z

SGC400

Z28Grade

For high strength structure use

St06Z

Hot galvanized sheet/strip used for deep drawing

St07Z

Surface structure

Characteristics

Use

Normal Spangle (Z)

After galvanization, cool the zinc layer under normal conditions to get the spangle.

Ordinary use

Small Spangle(X)

Spay liquid to the zinc layer and cool it to get minimized tiny spangle on the surface.

Used for surface appearances where normal spangle can not meet the requirements.

Skin passed spangle(GZ)

通Treat the surface with special skin-passing method to get fine uniform spangle.

Used for deep drawing requiring high quality surface state

Passivated with Chromic Acid

L

Painted with oil

Y

Passivated with chromic acid + painted with oil

LY

Galvanized layer forms

Galvanized layer categories

Pure zinc galvanized layer

Zinc-iron alloy galvanized layer

Uniform-thickness

40/40~225/225

30/30~90/90

Differential-thickness

30~150（per surface）

30~90（per surface）

Note：
① 50g/m2 of zinc galvanized approximately results in 7.1mm.
② For differential-thickness galvanized layer, the maximum ratio of differential thicknesses is 1:3
③ The average weight of galvanized layer from tests at 3 different sites on each surface shall not be lower than the standard weight of galvanized layer on the related surface, and the minimum weight of galvanized layer from tests at 3 different sites on each surface shall not be lower than 85% of the standard weight of galvanized layer on the related surface.