For housings, brackets, rail plates, and structures that will be welded or that need cost kept down, use 6061-T6. This is the usual default grade in the quote. It is a magnesium-silicon alloy, welds relatively well, can be milled, and can be mixed with sheet metal. Clear, black, and hard anodize can all be selected. For high load, fixture bodies, and fatigue duty, use 7075-T6. 7075 is stronger, can be milled, hard anodize is by selection, and weldability is ordinary. Higher strength is not a reason to make the wall thinner. Thin walls and threads still need an engineer to confirm.
Do not use 6061 as a substitute for 7075 at the same high load. 7075 is non-flight-critical by default. Welds must be agreed in advance. Thick hard anodize is scheduled again. Implant parts are not accepted. The page does not state AS or ISO certificate numbers.
Write the temper on the drawing. T6 is the usual one. T6 is the material supply temper. If quench and temper are not written, the quote is for the part as machined.
If a thin-wall part can be 6061, do not switch it to 7075 just to make it harder. When wall thickness is about below 1.0–1.2 mm and internal corners are sharp, chatter, distortion after anodize, and cracking at lightening-pocket corners are more likely. Lead time and cost for 7075 differ from 6061. How much they differ is the quote split.
From 1 piece. Preselect the grade on upload. Select finish and inspection in the quote. Special colors are agreed separately.
Upload a STEP, choose 6061-T6 or 7075-T6, select anodize or as-machined, and see the itemized reference price for that tier. A reference price is not a contract.