Galvanized Steel Coil

Specification

Item	Galvanized steel coil
Place of Origin	Shandong, China
Standard	AISI, ASTM, BS, DIN, JIS, GB, EN
Material	SGCC,SGCH,G550,DX51D, DX52D, DX53D, DX54D
Delivery Time	8-14 days
Technology	Hot Rolled/Cold Rolled
Zinc Coating	30-275g/m2
Thickness	0.12mm-6mm
Width	≤ 1500mm
Surface structure	Big spangle, small spangle, regular spangle, zero  spangle
Sample	Free Available
Payment term	TT 30% Advance + 70% Balance
Price Item	FOB, CIF, EXW, CFR, etc
Packing	Standard export packaging
Certification	ISO 9001, SGS, ABS, BV
MOQ	5 tons

Production Video

Core Advantages of GI Steel Coil

1. Strong corrosion and rust resistance: The galvanized layer isolates the steel coil from air and moisture, extending its lifespan.
2. High process adaptability: It can withstand various processing methods such as bending, stamping, welding, and shearing, and the coating is not easily peeled off. It is especially suitable for wall panels, frames, and vehicle bodies.
3. High cost-effectiveness: Low cost, mature production process, and low maintenance and replacement costs result in a significant overall cost advantage. A cost-effective alternative to high-priced anti-corrosion metals.
4. Diverse surface treatments: It can be layered with passivation, oiling, fingerprint-resistant coatings, and color coatings. For example, color-coated galvanized steel coils can be directly used as building exterior wall panels, and fingerprint-resistant treatments are suitable for appliance casings.
5. Wide strength range: Wanzhi Steel offers a full range of grades from low-strength, high-formability to high-strength structural grades, with stable performance within a temperature range from -40℃ to 200℃.

Application

• Construction: Steel structure factory roofs/walls, prefabricated house frames, curtain wall support components;
• Home appliances: Refrigerator/washing machine shells, such as our VCM/PET/PETG/EVA appliance panels, air conditioner outdoor unit brackets;
• Transportation: Automobile chassis parts, container bodies, billboard substrates, highway guardrails;
• Industry: Ventilation ducts, chemical equipment shells, livestock fences.

Industry Standards & Common Zinc Coatings

Chinese Standard (GB/T 2518)

The quality of the zinc coating is classified into grades such as Z80 (80g/㎡), Z100 (100g/㎡), Z120 (120g/㎡), Z150 (150g/㎡), Z200 (200g/㎡), and Z275 (275g/㎡).

American Standard (ASTM A653)

Corresponding to G60 (60g/㎡), G90 (90g/㎡), G115 (115g/㎡), G140 (140g/㎡), and G210 (210g/㎡).

EU Standard (EN 10346)

In line with China’s Z-series standards, Z275 (corresponding to G90) is commonly used as the benchmark for high corrosion resistance scenarios.

Note: The zinc layer weight is the total weight of both sides. For example, Z275 indicates that the total weight of the zinc layer on both sides is 275g/㎡, approximately 137.5g/㎡ on one side, and the thickness is approximately 19.6μm (the density of zinc is 7.14g/cm³).

Commonly Used Substrate Grades & Properties

The base material for galvanized steel coils is divided into hot-rolled steel (HC) and cold-rolled steel (CR), with different grades corresponding to different processing properties and strength levels:

Substrate Type	Typical brands (China)	Yield strength (MPa)	Elongation (%)
Cold-rolled steel	DC51D+Z	140-300	≥22
Cold-rolled steel	DC53D+Z	140-220	≥30
Cold-rolled steel	DC56D+Z	120-180	≥39
Hot-rolled steel	S220GD+Z	220	≥20
Hot-rolled steel	S350GD+Z	350	≥16

Character Definition

• “D” represents stamping, and “Z” represents hot-dip pure zinc coating.
• “S” represents structural use, “GD” represents cold forming compatibility, and “220 or 550” represents yield strength.
• “H” represents hard, suitable for high-hardness applications.

These designations are cross-standard (e.g., China DX51D+Z = Japan SGCC = Europe DX51D+Z), serving as a “common language” for industry procurement and design.

Grade Cross-Standard Correspondence Table

	GB/T Standard	JIS Standard	EN Standard	ASTM Standard
Commercial use	DX51D+Z（CR）	SGCC	DX51D+Z	ASTM A653 CS Type B
Deep drawing	DC53D+Z	SGCD2	DX53D+Z	ASTM A653 DS Type B
Ultra-deep drawing	DC56D+Z	SGCD3	DX56D+Z	ASTM A653 EDDS
Structural/load-bearing use	S220GD+Z	SG340	S220GD+Z	ASTM A653 SS Grade 33
Hard material use	S550GD+Z	SG570	S550GD+Z	ASTM A653 HSLA Grade 80

Recommended Selection for Different Environments

Arid Desert Environment

• Corrosion Grade: C1 (Low Corrosion)
• Recommended Zinc Coating: Z80-Z120 (80-120g/㎡)
• Reason: In low-humidity, low-salinity environments, a thin zinc coating is sufficient for over 10 years of corrosion protection.
• Countries: Iraq, Iran, Saudi Arabia, Egypt

Temperate Plains Environment

• Corrosion rating: C2 (low to medium corrosion)
• Recommended zinc coating: Z120-Z150 (120-150 g/m²)
• Reason: Suitable for moderate humidity, used for exterior walls and ordinary steel structures, with a lifespan of up to 15 years.
• Countries: Poland, Belarus, Czech Republic

Tropical Rainforest Environment

• Corrosion rating: C3 (Medium corrosion)
• Recommended zinc coating: Z200 (200g/㎡)
• Reason: In high humidity environments, a thick zinc coating can resist moisture corrosion, extending the lifespan of the roller-coated paint layer to 20 years.
• Countries: Peru, Indonesia, Brazil, Colombia

High-altitude and Cold Regions

• Corrosion rating: C2-C3 (low to medium corrosion)
• Recommended zinc coating: Z150-Z200 (150-200g/㎡)
• Logic: Humidity fluctuates greatly in low-temperature environments; the zinc coating needs to balance low-temperature toughness and corrosion resistance to avoid brittleness.
• Countries: Russia, Mongolia, Kazakhstan, Kyrgyzstan

Coastal/Marine Environment

• Corrosion rating: C4 (High corrosion)
• Recommended zinc coating: Z275 (275g/㎡)
• Logic: High salt spray, high humidity; Z275 combined with heavy-duty anti-corrosion coating can meet a service life of over 25 years.
• Countries: India, Philippines, South Africa, Chile

Process Types of Galvanized Coils

Electro-Galvanized Steel Coil

A zinc layer is formed through an electroplating process. The zinc layer is thin (5-30g/㎡) but has a smooth surface, making it suitable for indoor low-corrosion environments and small parts with high appearance requirements.

Hot-dip Galvanized Steel Coil

Surface Treatment for Extended Lifespan

1. Passivation Treatment: Forms a passivation film on the zinc layer surface, enhancing resistance to white rust.
2. Oiling Treatment: Sprays rust-preventive oil onto the surface, providing short-term rust protection and facilitating storage and transportation.
3. Fingerprint Resistant Treatment: Coats with a transparent organic film to prevent fingerprint residue.
4. Color Coating Treatment: Film coating/roller coating with four types of organic coatings: PVDF/PE/HDP/SMP, enhancing weather resistance.
5. Zinc Layer Alloying Treatment: Grade suffix + ZF, no zinc spangle, high hardness, and good wear resistance.
6. Phosphating + Painting Composite Treatment: Passivation followed by spraying of primer + topcoat. 3-5 times improvement in rust resistance.

Selection & Procurement Recommendations

1. Matching the Environment: Determine the corrosion level of the application environment, then select the corresponding zinc coating thickness to avoid over- or under-matching.
2. Base Material and Processing Requirements: For deep-drawn parts, select low-yield-strength grades such as DC53D+Z; for load-bearing components, select high-strength grades such as S350GD+Z.
3. Focus on Additional Services: Prioritize suppliers that can provide slitting, leveling, and customized packaging to reduce subsequent processing costs.

Price of HDG Coil

Material	Thickness	Zinc layer	FOB Qingdao Port (USD/ton)	FOB Tianjin Port (USD/ton)）
DX51D+Z	0.5mm	Z80	610 – 630	605 – 625
DX51D+Z	0.5mm	Z120	630 – 650	625 – 645
DX51D+Z	0.5mm	Z275	680 – 700	675 – 695
DX51D+Z	1.0mm	Z80	530 – 550	525 – 545
DX51D+Z	1.0mm	Z120	550 – 570	545 – 565
DX51D+Z	1.0mm	Z275	590 – 610	585 – 605
DX51D+Z	1.5mm	Z80	510 – 530	505 – 525
DX51D+Z	1.5mm	Z120	530 – 550	525 – 545
DX51D+Z	1.5mm	Z275	570 – 590	565 – 585
DX51D+Z	2.0mm	Z80	500 – 520	495 – 515
DX51D+Z	2.0mm	Z120	520 – 540	515 – 535
DX51D+Z	2.0mm	Z275	560 – 580	555 – 575
SGCC	0.5mm	Z80	615 – 635	610 – 630
SGCC	0.5mm	Z120	635 – 655	630 – 650
SGCC	0.5mm	Z275	685 – 705	680 – 700
SGCC	1.0mm	Z80	535 – 555	530 – 550
SGCC	1.0mm	Z120	555 – 575	550 – 570
SGCC	1.0mm	Z275	595 – 615	590 – 610
SGCC	1.5mm	Z80	515 – 535	510 – 530
SGCC	1.5mm	Z120	535 – 555	530 – 550
SGCC	1.5mm	Z275	575 – 595	570 – 590

Success Cases

FAQs

China Galvanized Coil Wholesale Manufacturer

Galvanized steel coils have become the core choice for industrial corrosion protection materials due to their “high cost-effectiveness and strong adaptability.” By matching the process, zinc layer thickness, and application, an optimal balance between performance and cost can be achieved.

Galvanized Steel Coil Factory-Wanzhi Steel

As a professional supplier with an annual production capacity of 400,000 tons, we can provide customized specifications and supporting processing services, covering the application needs of more than 120 countries worldwide.

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