Custom Hard Anodized 7075 Aluminium Tube for Precision Machined Components

Product Overview

7075 aluminium tube supplied with a hard anodized finish. 7075 is one of the strongest aluminium alloys in common use, with a zinc and magnesium composition that gives strength approaching that of mild steel at roughly a third of the weight. Hard anodizing then converts the outer surface into a dense oxide layer, so the part combines a stiff, light core with a hard wearing skin.

Hard Anodizing

Hard anodizing, also called Type III anodizing, is carried out at lower temperature and higher current density than decorative anodizing. The result is a thicker, denser oxide layer with markedly higher surface hardness than a standard clear or dyed finish. Because the layer grows out of the aluminium itself rather than sitting on top of it, it cannot peel or flake away. On copper bearing alloys such as 7075 the coating builds more slowly than on 6061, which is normal for the grade.

• Higher surface hardness and abrasion resistance than decorative anodizing
• Integral oxide layer, not a coating
• Available in natural or dyed colours, sealed after processing

Material Properties

7075 combines high tensile and yield strength with good fatigue resistance, which is why it is used for highly stressed parts in aerospace and high performance equipment. It machines cleanly, holds fine threads and takes a good surface finish, so it is normally specified for machined components rather than welded fabrications.

• Very high strength to weight ratio
• Good machinability and dimensional stability
• Best suited to machined rather than welded parts

Machining and Fabrication

Tubes are cut, faced, drilled, tapped, bored and CNC turned to drawing. Where the tube runs in a bore or carries a sliding fit, the hard anodized surface reduces galling and keeps the wear face stable over a long service life. Machining is completed before anodizing so that cut faces are covered by the oxide layer as well.

Typical Applications

• Precision machined components and spacers
• Wear bushes, sleeves and guide tubes
• Pneumatic and hydraulic cylinder parts
• Aerospace and motorsport fittings
• Robotics and automation wear parts

Quality Control

Tubes are inspected for alloy, temper, outside diameter, wall thickness and straightness before anodizing, and the finished parts are checked for coating uniformity, colour and surface defects.

Customization

Alloy, temper, tube size, wall thickness, length, machining features and anodizing type can be specified to drawing.