1.Where is the cold working adaptability of hot-dip galvanized steel plates reflected?
Excellent bending properties: The pure zinc layer exhibits excellent plasticity (elongation of approximately 20%). During conventional cold bending operations (such as 180° flat bends and 90° right-angle bends), the zinc layer stretches and contracts synchronously with the steel substrate, preventing cracking or flaking. (Care should be taken to avoid over-bending, which can cause localized thinning of the zinc layer. Generally, the bending radius should be ≥ the steel thickness.)
For example, when processing hot-dip galvanized structural keels, continuous bending into U- and C-shaped sections is possible without compromising the integrity of the zinc layer.
Stable stamping properties: For shallow and medium-strength parts (such as appliance back panels and small automotive brackets), hot-dip galvanized steel sheets can be stamped using dies without delamination or powdering of the zinc layer due to stamping stress. For deep drawing (e.g., complex curved parts), grades combining a low-alloy, high-strength substrate with a thin zinc layer (such as DC03 with hot-dip galvanizing) are recommended, achieving a balance between formability and protection. Reliable rolling/curling performance: In continuous rolling processes such as pipes and steel roll-up doors, hot-dip galvanized steel sheets can withstand repeated rolling deformation. The bonding strength between the zinc layer and the substrate (usually >100MPa) can resist the shear force during the rolling process and prevent the zinc layer from falling off.
2.What is the welding adaptability of hot-dip galvanized steel plates?
Compatible with various welding methods: resistance spot welding (mainstream in the automotive industry), CO2 gas shielded welding (common in the steel structure industry), and arc welding (for thick plate welding), requiring only targeted process parameter adjustments (e.g., increasing the current and shortening the on-time for spot welding to reduce zinc burnout; using silicon-containing wire for gas shielded welding to suppress zinc vapor porosity).
Guaranteed weld strength: After welding, the strength of the weld area is primarily determined by the steel substrate (comparable to the strength of ordinary steel welds). Simply applying a "re-galvanizing paint" or "cold zinc spraying" treatment to the weld surface can restore overall corrosion resistance.
For example, when welding hot-dip galvanized steel beams in a steel structure factory building, CO2 gas shielded welding can achieve weld strength exceeding 90% of the substrate strength.
No risk of weld embrittlement: The zinc layer does not form brittle phases with the steel substrate (such as intermetallic compounds in some coatings), maintaining the toughness of the steel plate after welding. This makes it particularly suitable for welding components in low-temperature environments (such as outdoor towers).
3.What is the cutting adaptability of hot-dip galvanized steel plates?
Mechanical cutting (cold cutting): such as shearing, laser cutting, and plasma cutting (cold cutting). During the cutting process, the zinc layer does not produce molten spatter, resulting in smooth cut edges. Only the "zinc slag" (a small amount adhering to the cut surface can be removed by grinding) needs to be removed before subsequent processing (such as welding or bending) can proceed directly.
For example, when laser cutting hot-dip galvanized steel sheets to produce precision parts, the cut accuracy can reach ±0.1mm, and the zinc layer has no effect on cutting accuracy.
Thermal cutting (flame cutting): Suitable for cutting thick plates (≥8mm). During cutting, the zinc layer burns with the flame to form zinc oxide, but it only adheres to the cut surface and can be removed by high-pressure water jets or grinding without affecting the mechanical properties of the cut.
4.What is the adaptability of subsequent surface treatment of hot-dip galvanized steel sheets?
Easy Degreasing and Rust Removal: Oil and dust on the hot-dip galvanized surface can be removed with standard degreasing agents (such as alkaline degreasing solutions). The zinc layer itself remains rust-free, eliminating the need for pickling and rust removal, simplifying the process.
Excellent Coating Adhesion: After degreasing, the hot-dip galvanized surface can be directly sprayed with powder coatings or solvent-based coatings (such as polyester paint or epoxy paint). The coating adhesion (cross-hatch test reaching level 0) is superior to that of cold-dip galvanized steel (which is physically adhered and prone to detachment).
For example, hot-dip galvanized refrigerator side panels in the home appliance industry are resistant to scratching and detachment after spraying with white polyester paint.
Compatible with Lamination/Printing: The hot-dip galvanized surface can be coated with PVC film (to protect it from scratches during transportation) or screen-printed with logos (such as equipment nameplates). The adhesion of both lamination and printing meets industrial requirements.
5.What is the adaptability of splicing and assembly of galvanized steel plates?
Bolted connections: Drilled holes can be used to secure directly with bolts. The zinc layer will not crack due to drilling, and the zinc layer around the bolt holes will still provide protection (if reinforcement is required, apply anti-rust grease inside the holes).
For example, the hot-dip galvanized frame of an outdoor billboard can be assembled with bolts, making it easy to install and rust-proof over time.
Riveted/clipped connections: Suitable for thin, hot-dip galvanized steel sheets (such as appliance housings). The zinc layer will not be crushed by the rivets during riveting, and the zinc layer can withstand the elastic stress of the clips and will not fall off during clipping.