1.What are the advantages of galvanized coil stamping?
Functionality meets economy: A single process yields complex, corrosion-resistant parts, eliminating the secondary steps of stamping and galvanizing, saving both cost and time.
Excellent base material performance: The core base material is made of steel specifically designed for deep drawing, offering excellent ductility and suitability for deformation, such as stretching and bending.
2.What are the challenges faced when stamping?
Zinc layer peeling/powdering: Under the tensile and extrusion effects of the mold, the zinc layer may develop microcracks or even fall off from the substrate. The detached zinc powder will adhere to the mold or part surface, affecting quality and mold life.
Surface scratches: If the mold surface is not smooth or has impurities, it will scratch the soft zinc layer, affecting the appearance and corrosion resistance of the parts.
Zinc slag sticking to the mold: The detached zinc powder will sinter and adhere to the mold surface under high temperature and high pressure, forming built-up edge, which will cause scratches or even damage to the surface of the part.
3.What are the key considerations when stamping?
Zinc Peeling/Powdering: Choose the right galvanized coil:
Coating Type: Pure zinc coating is preferred. It has better ductility than zinc-iron alloy coating and is more resistant to stamping deformation.
Coating Thickness: Choose a thinner coating. Thicker coatings are more susceptible to peeling. Choose grades such as Z60 or Z90 based on your needs.
Surface Treatment: Choose materials with an oiled surface to provide lubrication and reduce friction.
Optimize Die Design:
Reasonable Die Gap: The gap should be slightly larger than the material thickness to allow space for the zinc layer to flow and prevent excessive compression. A gap of 110% to 130% of the material thickness is generally recommended.
Sufficient Corner Radius: The corner radius of the punch and die should be moderate to avoid stress concentration and allow for smooth material flow.
High Finish and Hardness: The die (especially the drawbeads) should be polished and have a high hardness to reduce friction and zinc sticking. Process Control:
- Use of Specialized Lubricants: Even when the material is oily, adding additional stamping lubricant is extremely effective for complex molding.
Surface scratches: Keep the mold and material surfaces clean.
Ensure the mold surface is smooth.
Ensure adequate lubrication.
Zinc dross sticking to the mold: - Clean and maintain the mold regularly.
- Use an anti-stick mold material or coating.
- Maintain good lubrication to form a barrier.
4.What is the anti-corrosion performance after stamping?
Microcracks are normal: In areas of intense deformation, small cracks in the zinc layer are normal and usually invisible to the naked eye.
Sacrificial anodic protection persists: Zinc is chemically more reactive than iron. In the presence of electrolyte, even a discontinuous zinc layer will corrode before the iron, thereby protecting the exposed or nearly exposed steel substrate. This "sacrificial anodic" effect is particularly noticeable in scratches and cuts.
Overall corrosion protection remains superior: While the corrosion resistance of stamped areas is theoretically lower than that of flat areas, it is still orders of magnitude higher than that of ungalvanized stamped steel parts.
5.What is the applicable product range?
Home Appliance Industry: Refrigerator, air conditioner, and washing machine housings and internal components.
Automotive Industry: Fuel tanks, small chassis parts, brackets, housings, etc. (galvanized steel is often used).
Computer Cases and Cabinets: Computer cases, network communication cabinets, electrical control boxes, etc.
Construction Industry: Pipes, connectors, brackets, etc.