I. Classification by Core Function / Opening & Closing Method (Most Commonly Used Classification Logic)
Butt Hinge — Universal Basic Model
Core Function: Two-way free opening and closing, no automatic closing or buffering function. It is the most commonly used basic model in door hardware;
Structural Features: Composed of two leaves + a pin. The thickness of the leaves determines the load-bearing capacity, with common leaf thicknesses of 2.5mm/3mm/4mm;
Materials & Specifications:
Materials: 304 stainless steel (universal scenarios), 201 stainless steel (dry indoor environments), zinc alloy (low-end scenarios), copper alloy (high-end scenarios);
Specifications (adapted to door thickness): 3 inches (for wooden doors with thickness 35-45mm), 4 inches (for steel/wooden doors with thickness 45-55mm), 5 inches (for heavy-duty doors with thickness 55-70mm);
Applicable Scenarios: Indoor wooden doors, bedroom doors, office doors, light aluminum alloy doors (no need for silent/automatic closing functions);
Selection Points: For doors weighing ≤30kg, choose leaves with a thickness of 3mm; for doors weighing 30-50kg, choose 4mm thick leaves. Avoid leaf deformation caused by insufficient thickness.
Spring Hinge — Automatic Closing Model
Core Function: Built-in spring structure enables automatic rebound closing after the door is opened, eliminating the need for additional door closers;
Structural Features: The spring is hidden inside the leaves. The closing force is adjustable (by adjusting the screw to control spring tension), and some models have positioning functions (e.g., 90° positioning to fix the door when opened to 90°);
Materials & Specifications:
Materials: 304 stainless steel (rust-resistant), zinc alloy (dry indoor environments);
Specifications: 3 inches/4 inches/5 inches, with a maximum load-bearing capacity of 40kg;
Applicable Scenarios: Bathroom doors, kitchen doors, public area doors (needing automatic closing and insufficient space for door closers);
Selection Points: Do not use for heavy-duty doors (≥50kg) as springs are prone to fatigue and failure; select 304 stainless steel for humid environments to prevent spring rust and jamming.
Hydraulic Hinge — Silent Buffering Model
Core Function: Integrated hydraulic damper ensures slow buffering when closing the door, avoiding collisions between the door and frame, and achieving "silence + anti-pinch protection";
Structural Features: Built-in hydraulic oil chamber in the leaves allows adjustable closing speed (buffering within 0-90° opening angle). Some models combine hydraulic and spring functions for automatic closing;
Materials & Specifications:
Materials: 304 stainless steel (main body) + high-quality hydraulic oil (stable damping);
Specifications: 4 inches/5 inches/6 inches, with a load-bearing capacity of 30-80kg;
Applicable Scenarios: High-end indoor doors, children's room doors, hotel doors, office doors (high requirements for silence and user experience);
Selection Points: Focus on hydraulic damper lifespan (≥100,000 opening/closing cycles without oil leakage); for doors weighing 50-80kg, choose 6-inch heavy-duty hydraulic hinges to avoid excessive closing speed due to insufficient damping force.
Heavy-Duty Hinge — High Load-Bearing Model
Core Function: Thickened leaves and thickened pins adapt to ultra-heavy doors, ensuring stable long-term opening and closing;
Structural Features: Leaf thickness ≥5mm, pin diameter ≥12mm. Some models adopt a double-bearing design (reducing friction and improving smoothness) with a load-bearing capacity of 50-200kg;
Materials & Specifications:
Materials: 304/316 stainless steel (corrosion-resistant), carbon steel (galvanized for rust prevention, suitable for dry indoor environments);
Specifications: 6 inches/8 inches/10 inches, leaf width ≥75mm;
Applicable Scenarios: Security doors, industrial doors, large double doors, heavy-duty glass doors, villa entrance doors (door weight ≥50kg);
Selection Points: For doors weighing 50-100kg, choose 6-inch double-bearing hinges; for 100-200kg, choose 8-10-inch thickened hinges. It is recommended to install 3-4 hinges per door (2 for regular doors).
Concealed Hinge — Aesthetic Hidden Model
Core Function: Fully hidden inside the door and frame after installation, with no exposed components, enhancing the overall aesthetics of the door;
Structural Features: Adopts 3D adjustment design (adjustable forward/backward, left/right, up/down). The opening angle can reach 180°, and some models have buffering functions;
Materials & Specifications:
Materials: 304 stainless steel, aluminum alloy (lightweight);
Load-Bearing Capacity: 20-60kg (lightweight concealed hinges), 60-120kg (heavy-duty concealed hinges);
Applicable Scenarios: High-end wooden doors, frameless doors, invisible doors, minimalist-style decoration doors (high requirements for aesthetics);
Selection Points: Concealed hinges require high installation precision and need to be matched with special door frame grooving. It is recommended to choose models with adjustment functions (facilitating installation and debugging); prioritize stainless steel for heavy-duty concealed hinges to avoid deformation.
Translation Notes
Term Consistency: Adheres to the established B2B door hardware terminology system (e.g., "合页" → "Hinge", "304 不锈钢" → "304 stainless steel", "承重" → "load-bearing capacity") to ensure global procurement recognition;
Parameter Accuracy: Retains original technical parameters (e.g., dimensions, thickness, load-bearing capacity) and uses international standard units (inches, mm, kg) without conversion errors;
Structural Clarity: Maintains the original hierarchical structure (core function → structural features → materials & specifications → applicable scenarios → selection points) with consistent formatting (bold headings, bullet points) for easy skimming by overseas buyers;
Industry Adaptation: Uses formal business English with technical accuracy (e.g., "液压阻尼器" → "hydraulic damper", "三维调节设计" → "3D adjustment design") and avoids colloquial expressions, aligning with B2B procurement document standards;
Practicality: Optimizes sentence structure for technical scenario 适配 (e.g., "避免页板过薄导致变形" → "Avoid leaf deformation caused by insufficient thickness") to ensure clear guidance for overseas buyers' selection and application.