OEM customized, Cut by drawings
EMERSONMETAL
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Processing Z350 galvanized steel demands distinct expertise. The thick zinc layer generates significant vapor during laser cutting, requiring specialized gas dynamics and parameter control to prevent porosity, edge embrittlement, and surface spatter. Our facility has developed dedicated process protocols for this heavy-gauge coating class, delivering clean cut edges that retain corrosion protection even at the kerf boundary.
Z350 Grade Chemical Composition and Technical Property is as below：
Standard | C % | Mn max | P max | S max | tensile strength（MPa） | yield strength（MPa） | Elongation% |
Z350 | 0.3 | 1.6 | 0.1 | 0.035 | 420 | ≥350 | ≥14 |
| Parameter | Details |
| Base Steel Grade | CSA CSB / ASTM A653 CS Type B / EN 10346 DX51D+Z |
| Zinc Coating | Z350 (350 g/m² total, both sides) |
| Equivalent Coating | G90 heavy commercial / Z35 per EN |
| Thickness | 0.5mm – 6.0mm (laser cutting optimized) |
| Max Cutting | 4,000mm × 2,000mm |
| Laser Cutting | ±0.05mm – ±0.15mm |
| Surface Finish | Regular Spangle / Minimized Spangle / Skin Passed |
| Coating Grade | Total Zinc Weight |
| Z180 | 180 g/m² |
| Z275 | 275 g/m² |
| Z350 | 350 g/m² |
Q1: What does Z350 mean, and how does it compare to G90 or Z275?
A: Z350 indicates a total zinc coating weight of 350 grams per square meter on both surfaces combined (approximately 175 g/m² per side). This is significantly heavier than Z275 (common for general construction) and G90 (approximately 275 g/m² total). Z350 is specified for coastal, marine, heavy industrial, or long-design-life applications where maximum sacrificial corrosion protection is required.
Q2: Is CSA CSB the same as ASTM A653 CS Type B?
A: Yes, they are closely aligned. CSA CSB refers to Commercial Steel Type B under Canadian/ASTM nomenclature, a forming-quality low-carbon steel with guaranteed mechanical properties and excellent weldability. It is widely used as the substrate for heavy-gauge galvanized products in North American and export markets.
Q3: Does laser cutting destroy the Z350 coating at the cut edge?
A: The laser beam melts and partially vaporizes the zinc directly at the kerf, but the adjacent heavy zinc coating provides substantial sacrificial material. Upon resolidification, a zinc-rich layer forms on the exposed steel edge, offering continued protection. For the most aggressive environments, we recommend applying zinc-rich touch-up paint to laser-cut edges to restore the full 350 g/m² equivalent barrier.
Q4: Can Z350 sheet be formed into complex shapes without the zinc coating cracking?
A: Z350 accommodates moderate bending, roll forming, and drawing. Inside bend radii should be at least 2× to 3× the material thickness to minimize zinc crazing (fine surface cracking). While crazing is generally cosmetic and does not expose the base steel in mild bends, very tight radius forming may require post-form zinc repair or the use of a more formable substrate.
Q5: Why is Z350 more expensive than standard Z275, and when is it worth the premium?
A: The higher cost reflects additional zinc consumed in the hot-dip bath and the heavier material handling. Z350 is worth the investment when the lifecycle cost of maintenance, repainting, or replacement is considered. For structures in coastal zones, chemical plants, or remote locations where access for maintenance is difficult, Z350 often pays for itself within the first decade of service.
Q6: Can you weld Z350 galvanized steel without removing the coating?
A: Yes, but proper ventilation is essential because welding vaporizes zinc, creating fumes that must be extracted. For high-integrity welds, grinding the zinc back 20–30 mm from the joint line is recommended. Post-weld, the joint area should be cleaned and touched up with zinc-rich paint or cold galvanizing compound to restore corrosion protection.
