1.What are the key attributes of a DC06 part?
Forming Complexity: DC06 is primarily used for ultra-deep drawing parts (such as automotive interiors and appliance linings). If the part requires complex bending and stretching (such as deep cylindrical parts), thin coatings/flexible coatings (such as electroplated galvanizing or thin resin coatings) are preferred to avoid cracking during forming due to the brittleness of thick coatings (such as hot-dip galvanizing). For simple parts (such as flat panel brackets), the coating thickness restriction can be relaxed.
Corrosion Resistance Requirements: Based on the corrosion intensity of the operating environment, specify "mild corrosion resistance" (such as dry indoor environments), "moderate corrosion resistance" (such as high humidity environments), and "heavy corrosion resistance" (such as light outdoor use and contact with liquids) to avoid costly over-protection or rust-inducing under-protection.
Additional Requirements: Whether decorative finishes (such as glossy finishes or colors) are required, food contact safety (such as appliance linings), temperature resistance (such as oven parts), and wear resistance (such as high-frequency contact parts) are required. These requirements may directly exclude certain coating/plating types (for example, chrome plating containing heavy metals is excluded for food contact applications).
2.With "ultra-deep drawing" as the core requirement, how to choose the coating?
Core requirements: The coating/plating must be highly flexible, not affect the elongation (≥40%) and formability of DC06, and avoid coating peeling and plating cracking during forming.
Recommended Solution: Electrogalvanizing (thin coating) + Chromium-Free Passivation
Specific Parameters: Coating thickness 5-10μm (thinner than hot-dip galvanizing), passivation layer thickness 0.1-0.5μm (chromium-free passivation is more environmentally friendly);
Key Advantages:
The zinc coating offers excellent flexibility, highly compatible with the formability of DC06, and is less susceptible to cracking after deep drawing;
The thin coating does not increase part thickness and does not affect mold accuracy (e.g., deep-drawing of automotive instrument panel brackets);
After passivation, it can withstand a neutral salt spray test for 240-480 hours, meeting the requirements of high-humidity indoor environments (e.g., automotive cockpits);
Applications: Ultra-deep-drawn automotive interior parts (e.g., door panels), deep-drum components for home appliances (e.g., washing machine drum brackets), and parts requiring moisture resistance after forming;
Remedies: Hot-dip galvanizing (thick coating, brittle, prone to cracking during forming); thick resin coating (prone to peeling during forming).
3.With "long-term moisture resistance/light outdoor" as the core requirement, how to choose the right coating?
Option 1: Electrogalvanizing (10-15μm) + Chromate Passivation
Corrosion Resistance: Salt spray test resistance can reach 480-720 hours, a 50% improvement over thin coatings. Suitable for long-term bathroom humidity (e.g., towel racks, storage racks).
Advantages: Maintains a certain degree of formability, suitable for moderately complex curved parts (e.g., U-shaped brackets).
Option 2: Hot-Dip Galvanizing (20-50μm)
Corrosion Resistance: Salt spray test resistance can reach over 720 hours, offering the highest corrosion resistance. Suitable for light outdoor exposure (e.g., balcony air conditioner brackets).
Limitations: The thick coating and high hardness significantly reduce the formability of DC06. It is only suitable for simple parts that are "formed first, then hot-dip coated" (e.g., flat plates, straight rod brackets) and not for deep-drawn parts.
Applications: Bathroom hardware, balcony outdoor brackets, and parts exposed to condensation (e.g., air conditioner outdoor unit brackets).
Removal Options: Bare part passivation (inadequate corrosion resistance), thin resin coating (prone to peeling in prolonged moisture).
4.With "appearance decoration + moderate corrosion resistance" as the core requirements, how to choose the right coating?
Option 1: Chrome Plating (2-5μm) / Nickel Plating (3-8μm)
Appearance: Mirror-like finish with high precision (Ra ≤ 0.2μm), suitable for instrument panels and high-end hardware (e.g., audio knobs).
Corrosion Resistance: Nickel plating withstands salt spray tests for up to 360-480 hours, while chrome plating offers superior resistance (over 500 hours), and is resistant to mild indoor pollution.
Note: The thin coating and reduced brittleness make it suitable for simple curved parts (e.g., curved panels). However, the cost is higher than zinc plating and it contains heavy metals (must comply with environmental standards such as RoHS).
Option 2: Colored Organic Coating (e.g., powder coating, amino paint).
Appearance: Available colors (black, white, or colored), with matte or high-gloss finishes. Suitable for appliance exteriors (e.g., microwave oven housings).
Corrosion Resistance: Coating thickness 15-30μm, salt spray test resistance up to 300-400 hours, environmentally friendly and heavy metal-free.
Note: Requires DC06 Post-molding spraying (to prevent coating flaking during molding) is suitable for parts requiring no secondary processing.
Applications: Instrument panels, appliance exterior parts, and high-end decorative hardware.
Removal options: Hot-dip galvanizing (rough surface, no decorative effect), phosphating (provides only for auxiliary protection, no cosmetic effect).
5.With "food contact safety" as the core requirement, how to choose the right coating?
Core requirements: The coating must comply with food contact safety standards (e.g., GB 4806, FDA), be free of heavy metals and odor, and be resistant to corrosion from food juices (e.g., acidic and oily).
Recommended Options: Food-Grade Epoxy Coating / Food-Grade Galvanizing (Special Treatment)
Option 1: Food-Grade Epoxy Coating (10-20μm)
Safety: The coating is made of food-grade epoxy resin, free of benzene and heavy metals, and complies with GB 4806.1-2016.
Corrosion Resistance: Resistant to acids (such as vinegar and juice) and oils (such as cooking oil), it exhibits no peeling or odor even after long-term contact with food.
Applications: Refrigerator linings, food storage containers, and small kitchen appliance linings (such as rice cooker lid brackets).
Option 2: Food-Grade Galvanizing (5-8μm) + Chromium-Free Passivation
Safety: The zinc coating must contain controlled heavy metal impurities (e.g., lead and cadmium content ≤ 100ppm). The passivation layer must be chromium-free and environmentally friendly (e.g., zirconate).
Applications: Simple parts of food processing equipment (such as conveyor brackets), but must avoid direct contact with acidic foods (zinc is easily corroded by acids).
Removal Options: Chrome Plating / Nickel plating (contains heavy metals, not suitable for food contact), ordinary resin coating (may contain volatile organic compounds).