Customized Anodized Small Diameter Aluminium Alloy Tube (7005 / 7075)
Small diameter aluminium alloy tube is extruded as a seamless hollow section and then drawn over a mandrel to the diameter and wall thickness on the customer drawing. Drawing refines roundness and the internal surface, so the bore stays concentric with the outside diameter along the whole length, and the tube can be supplied straight or coiled, cut to a fixed length, or left as stock for further forming. The 7005 and 7075 grades give a light, stiff tube, so a small section can replace a heavier steel part.
Alloys, Temper and Strength
7005 and 7075 are age hardenable alloys with zinc and magnesium as the main additions. Both give a high strength to weight ratio, good fatigue behaviour and useful stiffness for their mass. 7005 is the more weldable of the two and suits tubes that are joined after bending or cutting; 7075 develops higher strength and suits structural members that are not welded. Temper and wall thickness are chosen with the diameter to meet the stiffness and weight target.
Anodizing and Corrosion Resistance
The anodized finish is grown from the aluminium itself, forming a hard oxide layer that is integral to the surface rather than a coating that can flake. On small diameter tubes the film protects against corrosion in humid, coastal and outdoor service, resists abrasion where tubes slide inside one another, and gives a stable colour base. Film thickness, colour and gloss are agreed with the customer, and tubes in one order are anodized together for consistent shade.
Bending, Welding and End Forming
The tube is supplied in a condition that allows bending and welding. Bends are made on mandrel or rotary draw benders to the radius and angle on the drawing, with the wall chosen so the outside of the bend does not flatten. Ends can be swaged, flared, threaded or crimped so sections fit together. Where the tube is welded, the alloy and temper are selected for the joint, and anodizing follows welding so the oxide layer stays continuous.
Typical Applications
Small diameter seamless aluminium tube is used for tent poles and tarp supports, telescopic and folding frame sections, trekking poles, light stands and display frames, antenna and mast sections, bicycle frame parts and light structural spacers. In these uses the seamless bore, small diameter, high strength alloy and anodized finish together give a tube that is stiff, light and weather resistant.
Ordering
Orders are produced to the customer drawing. Please state the alloy and temper, the diameter and wall thickness, the cut or coil length, the bend radius and angle if bending is required, and the anodizing colour and film thickness. Send your drawing or sample so the tube can be produced to it.
