1. What are cold-rolled coil scraps? What are their main classifications?
A: Cold-rolled coil scraps refer to various edge wastes and scraps generated during cold rolling, pickling, or downstream stamping processes. Based on their source and form, they can be mainly classified as follows:
Scrap Edges: These are strips of scrap cut off at the shearing line to ensure the finished product width or to remove edge defects in the strip. The cut edge width is typically between 5 and 25 mm.
Lightweight Material (Punching Material): This mainly refers to the edge material remaining after stamping of cold-rolled sheets with a thickness between 0.2 mm and 4.0 mm. This type of material has fewer impurities and better quality, and is also called "punching material" in some regions.
Head and Tail Plates/Surplus Material: This refers to the portions cut off from both ends of the steel coil due to quality or dimensional issues, as well as irregularly shaped and sized remaining sheet material that cannot be directly used in the original order.
Other Scrap Materials: This includes waste strapping, protective rings, and other packaging materials, as well as finer scrap edges for remelting.
2. What are the differences in processing techniques for cold-rolled scrap wire of different thicknesses?
A: The processing techniques for cold-rolled scrap wire are mainly selected based on its thickness and toughness, and can be broadly divided into the following two categories:
Thin material (thickness < 3mm): For thin material with a thickness of less than 3mm and good toughness, a "scrap wire coiler" is typically used. This equipment can coil the scrap wire into a tight roll, facilitating collection, transportation, and subsequent processing. This method can also be used for even thinner (0.15~2mm) and softer scrap wire.
Thick/hard material (thickness > 3mm): For thick material with a thickness greater than 3mm or brittle materials, such as high-strength steel, a "scrap wire shear" is typically used. The scrap wire shear cuts the scrap wire into small segments of approximately 100mm to 250mm in length, which are then collected via a conveyor chain. This method is effective in processing high-strength, difficult-to-coil scrap.
3. How does a briquetting machine process scrap materials? What are its advantages?
A: Briquetting machines are mainly used in high-speed production lines such as continuous annealing and galvanizing to process continuous waste wire cut by disc shearing. The workflow is as follows: the waste wire falls into the briquetting machine's hopper through a channel. Once a set weight is collected, the hydraulic system compresses, cuts, and finally ejects it into compact blocks. Its advantages are mainly reflected in:
High efficiency: It can adapt to line speeds up to 800 meters per minute, perfectly matching high-speed production lines without affecting the main process.
Easy storage and transportation: The volume of the compressed scrap is significantly reduced, facilitating stacking, transportation, and remelting.
Increased yield: By optimizing briquetting machine parameters (such as setting scrap block weights of 90-120 kg for different steel grades), stable equipment operation can be ensured, significantly improving the online edge-cutting completion rate, thereby avoiding additional post-processing steps.
4. How to make high-value use of scrap materials?
A: For scrap materials with acceptable size and shape, direct recycling is not the optimal choice. Deep processing can significantly increase their added value. Common high-value utilization methods include:
Processing into wire (steel wire): Cold-rolled scrap wire in coils can be processed into standard-specification steel wires with diameters of 3.0-6.0mm through continuous rolling and drawing processes for use in manufacturing various metal products.
Production of hardware stamping parts: Using relatively regular-shaped end plates and scrap materials, products such as motor laminations, cable trays, office furniture components, and cabinet housings can be manufactured through processes such as cross-cutting, slitting, and stamping.
Manufacturing steelmaking coolant: Some steel rolling scrap materials can be processed into specific shapes and used as coolants in the steelmaking process.
5. What safety and compliance issues need to be considered when handling cold-rolled scrap?
A: Handling scrap is not only a technical issue but also involves production safety and regulatory compliance. The following points should be noted:
Safety in Production: The scrap handling area (such as around the scrap coiling machine) is an accident-prone area, posing risks of crushing, scratches, and falls. Enterprises should improve equipment (such as optimizing briquetting machines) and operating methods to reduce direct human intervention and eliminate safety hazards at the source.
Environmental Compliance: Waste acid and waste emulsion generated during cold rolling production are hazardous wastes. Their disposal must be handled by qualified professional companies, and environmental regulations must be strictly enforced.
Trade Compliance: When involved in import and export business, cold-rolled scrap has a specific HS code (such as 7204410000). Accurate classification and proper handling are required during declaration. For bonded scrap under processing trade, domestic sales require declaration to customs and payment of taxes in accordance with the law.
Transaction compliance: When bidding or transferring goods online, buyers are usually required to inspect the goods in person for confirmation. After winning the bid, they cannot raise objections on the grounds that they have not inspected the goods.