Industrial Steel Storage Racks Manufacturing Process ！

1. Raw Material Selection & Preparation

• Steel Type Selection:
   
  Common materials include cold-rolled steel sheets (CRS) (thickness: 0.8–4.0mm, for shelves, side panels, and 横梁 connectors) and hot-rolled steel coils/bars (for load-bearing beams and upright posts, with yield strength ≥ 235MPa or ≥ 345MPa for heavy-duty racks). For corrosion-prone environments (e.g., warehouses with high humidity), galvanized steel or stainless steel (304/316) may be used.
• Material Cutting:
   
  Raw steel coils/sheets are first uncoiled and leveled to eliminate internal stress (via a leveling machine). Then, they are cut into fixed-length blanks using CNC shearing machines (for sheets) or band saws (for steel bars), ensuring dimensional accuracy (tolerance ≤ ±0.5mm).

2. Precision Forming: Shaping Core Components

• Key Equipment: Roll Forming Machine:
   
  Most components are shaped via CNC roll forming—a continuous process where steel blanks pass through a series of paired rollers (10–20 sets, depending on the design). Each roller gradually bends the steel into the desired cross-section (e.g., upright posts with "double C" profiles for stability, beams with "P-shaped" hooks for easy assembly).
  • Advantage: High efficiency (up to 15–30 meters per minute) and consistent dimensional precision, avoiding deformation caused by traditional stamping.
• Special Shaping (if needed):
   
  For complex parts (e.g., rack feet, reinforcement plates), CNC punching machines or laser cutting machines are used to create holes, notches, or custom shapes (e.g., mounting holes for bolts, hook slots for beams).

3. Welding: Assembling Structural Frameworks

• Welding Methods:
  • MIG Welding (Metal Inert Gas Welding): Used for thick steel components (e.g., upright posts and base plates) to ensure strong, seamless joints. Inert gas (argon) prevents oxidation during welding.
  • Spot Welding: Applied to thin-sheet components (e.g., shelf panels and side ribs) for fast, efficient bonding without excessive heat deformation.
• Welding Quality Control:
   
  Welds are inspected for defects (e.g., cracks, porosity, incomplete fusion) using visual checks or ultrasonic testing. Weld seams are also ground smooth to avoid sharp edges (a safety hazard for operators).

4. Surface Treatment: Corrosion Resistance & Aesthetics

A. Powder Coating (Most Widely Used)

1. Pre-Treatment:
   • Degreasing: Soak or spray components in alkaline cleaner to remove oil, dirt, or rust.
   • Derusting: Use acid pickling (for heavy rust) or sandblasting (for smooth surfaces) to eliminate iron oxide.
   • Phosphating: Apply a phosphate film (5–10μm thick) to the steel surface to improve powder adhesion and corrosion resistance.
   • Drying: Bake components at 120–150°C to remove moisture.
2. Powder Spraying:
    
   Use an electrostatic spray gun to coat components with dry powder (polyester, epoxy, or hybrid powders). The electrostatic charge ensures uniform coverage (even on complex shapes).
3. Curing:
    
   Bake components in an oven at 180–220°C for 15–25 minutes. The powder melts, flows, and forms a hard, smooth film (60–120μm thick) with high impact resistance.

B. Hot-Dip Galvanizing (For High-Corrosion Environments)

• Suitable for racks used in outdoor warehouses, cold storage, or chemical plants.
• Process: Immerse cleaned steel components in a molten zinc bath (440–460°C) for 3–5 minutes. Zinc adheres to the steel surface, forming a thick (50–100μm) zinc layer that provides long-term corrosion resistance (up to 20+ years).

5. Assembly (Semi-Finished or Finished)

• KD Assembly Preparation:
   
  Manufacturers package individual components (upright posts, beams, shelves, bolts, nuts) with assembly instructions. Critical parts (e.g., beam hooks, upright connectors) are pre-installed or labeled for quick on-site assembly.
• Pre-Assembly Testing (for heavy-duty racks):
   
  For large racks (e.g., pallet racks with load capacities ≥ 1 ton/level), a sample unit is fully assembled to test load-bearing performance (via static/dynamic load tests) and structural stability.

6. Quality Inspection & Packaging

• Inspection Items:
  • Dimensional Accuracy: Check component sizes (e.g., upright height, beam length) with calipers or tape measures (tolerance ≤ ±1mm).
  • Load-Bearing Test: Apply rated loads (120% of the design load for 24 hours) to verify no permanent deformation.
  • Surface Quality: Check for coating defects (e.g., chips, bubbles, uneven color) or sharp edges.
  • Safety Compliance: Ensure components meet anti-tip standards (e.g., base plate weight, diagonal bracing) and have no structural weaknesses.
• Packaging:
  • Wrap components in plastic film or bubble wrap to prevent scratches during transportation.
  • Use cardboard boxes or wooden pallets for fragile parts (e.g., shelf panels).
  • Label packages with part numbers, quantities, and handling instructions (e.g., "Heavy Load—Do Not Stack").

Key Factors Influencing Manufacturing Quality