Aluminum Alloy Railing Production Process (Actual Process Flow)

Design: Complete product structural design and appearance styling according to customer requirements and application scenarios (balcony, staircase, fence, etc.).
Mold Development: Develop hot extrusion dies for aluminum alloy railings based on the designed profile cross‑section. These dies are later used to extrude aluminum billets into profiles with specific shapes.

Batching: Prepare aluminum ingots and alloying elements (magnesium, silicon, etc.) in proportion. The common grade is 6063 aluminum alloy (good formability and weldability).
Melting: Melt the batched raw materials in a melting furnace.
Casting: The molten aluminum is cast via a deep‑well casting system, cooled and solidified into round cast billets of various specifications.

Heating: Heat the round aluminum billets to 400–550°C to soften them.
Extrusion: Load the heated billets into an extrusion press and force them through a pre‑heated die to produce profiles with the required railing cross‑section. Common press capacities range from 1,000 to 3,000 tons.
Cooling (Quenching) : The extruded profiles are air‑cooled or water‑quenched (T5/T6 process).
Straightening: Use a stretch straightener to eliminate bending deformation.
Cutting: Cut the straightened profiles to predetermined lengths (e.g., 6 m).
Aging: Load the profiles into an aging furnace at about 200°C for several hours to increase hardness, strength, and toughness.

Cut‑to‑length: Precisely cut the extruded profiles according to the railing design dimensions.
Punching: Perform punching operations (welding holes, assembly holes, decorative holes, etc.).
Bending (if required) : Cold‑bend beams and arched decorative parts.
Welding:
- Automated welding: Robotic welding (e.g., TIG or laser welding) along a programmed path, enabling 24/7 continuous production.
- Welding types: Butt welding or full‑penetration welding. Full welding provides higher strength and is used where stability and safety are critical.
- Grinding: Grind and polish welded areas to remove marks and make the surface smooth.

Loading: Hang workpieces on baskets or a conveyor chain.
Degreasing: Remove grease and dirt with a degreaser.
Water rinse: Clean with tap water.
Etching (optional) : Use an alkaline solution to further clean the surface.
Water rinse: Rinse again.
Surface conditioning (neutralization) : Neutralize acid/alkali residues.
Water rinse: Rinse again.
Passivation (chromating) : For high‑precision requirement railings, apply chromating to form a conversion film that enhances coating adhesion and corrosion resistance.
Water rinse: Rinse off passivation solution.
Hot water rinse: Use deionised hot water for final cleaning.
Drip drying: Remove water droplets with dedicated equipment and airflow.
Pre‑drying: Dry the workpieces in an oven before coating.
Racking: Transfer workpieces to the coating loading area.

Spraying: The workpiece is grounded (negative charge) and powder receives a positive charge from the spray gun, so it adheres electrostatically to the aluminum surface. Typical coating thickness: 60–80 μm.
Curing: Coated parts enter a curing oven (approx. 180–240°C for 10–20 min). The powder melts, levels, and forms a dense anti‑corrosion film.
Unloading: Remove finished railing components from the coating line.

Note: Other common finishes for aluminum railings include anodising, electrophoresis, and wood grain heat transfer.

Accessory production: Manufacture or purchase connectors, bolts, end caps, and other hardware.
Assembly: Join profiles and hardware. Two main methods exist:
- Assembled (screw‑free) : Use stainless steel self‑tapping screws or rivets. No visible screws; detachable.
- Fully welded: Joints are double‑sided full‑penetration aluminium welding – the connection points fuse together, offering higher integrity and impact resistance.

Dimensional inspection: Check flatness and diagonal dimensions to ensure assembly accuracy.
Weld inspection: Ensure no porosity, cracks, undercutting, or other defects.
Coating inspection: Measure thickness with a film gauge; test adhesion with the cross‑cut method.
Salt spray test: Perform neutral salt spray (NSS) sampling to verify corrosion resistance.
Strength test: Load test (e.g., uniformly distributed load on the top rail) to verify structural safety.

Packaging: Wrap with protective film and straps; pack assembled parts in wooden crates or steel frames to avoid damage during transit.
Transport: Deliver to the construction site via logistics.
On‑site installation: Fix the railing to the concrete base with expansion bolts or embedded steel bars.
Acceptance: Final inspection and handover after installation.

Applicable Standards

GB/T 5237.1 – Wrought aluminium alloy extruded profiles for architecture: technical requirements, test methods, inspection rules.
JGJ/T 470‑2019 – Technical standard for building protection railings. Specifies minimum wall thickness: ≥3.0 mm for aluminium tube posts, ≥2.0 mm for handrails.
T/QGCML 1526‑2023 – General requirements, structural requirements, and test methods for aluminium alloy fences.

Aluminium alloy railings are generally produced in two main ways regarding joint connection:

Assembled (screw‑free)	Fully welded (double‑sided full‑penetration)
Stainless steel self‑tapping screws or rivets	Joints are fused by double‑sided full‑penetration aluminium welding
No visible screws; detachable	Connection points become one solid piece
Convenient transport and installation	Higher overall integrity and impact resistance
Suitable for general projects	Recommended for high‑safety villas and premium residences

Both processes share the same front‑end steps (extrusion, surface treatment, etc.); the main difference lies in the frame connection method.