# Aluminum in Manufacturing
Aluminum is specified by grade and temper together, because 6061-T6 and 6061-T651 behave differently in a stress-critical part. A capability page naming the family without the temper has stated half the requirement.

# Aluminum in Manufacturing

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Aluminum is specified by grade and temper together, because 6061-T6 and 6061-T651 behave differently in a stress-critical part. A capability page naming the family without the temper has stated half the requirement.

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The most common material on an industrial capability page is also the one described least precisely. The programme argument that turns on that precision is in [manufacturing SEO](/manufacturing-seo).

## The grades a drawing actually calls

**6061 is the general-purpose structural grade** and the one most machined parts are cut from, strong enough for most brackets and housings and readily weldable.

**7075 is the high-strength aerospace grade**, substantially stronger than 6061 and not weldable in the same way, which is why substituting one for the other is a design decision rather than a purchasing one.

**2024 sits in aerospace structure** where fatigue performance matters. **5052 is the sheet grade** for formed and welded work. **MIC-6 and cast tooling plate are the flat, stable stock** used for fixtures and baseplates.

A page naming these grades matches a drawing. A page saying "aluminum" matches nothing.

## Temper is half the specification

**A temper designation records the heat treatment and mechanical processing the material has had**, and it changes strength, machinability, and dimensional stability.

T6 is solution heat treated and artificially aged. **T651 adds a stress-relieving stretch**, which is why it is specified for parts that must stay flat after material is removed. A thin plate machined from T6 rather than T651 can move on the table, and the part is out of tolerance without anything having been machined wrongly.

That is the pairing a supplier has to understand to quote: **material condition constrains achievable [tolerance](/glossary/tolerance)**, and a request naming a tight flatness with the wrong temper is a conversation rather than a quote.

## What constrains the quote

**Aluminum work-hardens and galls**, which drives tooling and speed choices rather than feasibility, and it is why an achievable [surface finish](/glossary/surface-finish-ra) differs by grade.

**Anodising type and class belong in the request**, since Type II and Type III differ in thickness and hardness and change the finished dimension. A part machined to nominal and then hard anodised is out of tolerance by the coating thickness.

## What a capability page should state

**A capability page must state process, materials, tolerances, capacity, certifications, and industries served**, and aluminum belongs in that list as grades and tempers rather than as a family.

State the grades routinely run, the forms held or bought, the maximum envelope, and the finishing coordinated. That is the vocabulary the rest of the corpus draws on, set out at [capability page structure](/content/capability-page-structure), and the wider cluster reasoning is at [materials](/materials).

## Common questions

**Is 6061 always the right default?**

For general machined parts, usually. Strength-critical aerospace work calls 7075 or 2024, and sheet work calls 5052.

**Does temper need stating on a capability page?**

Yes where the shop runs specific tempers. It is the difference between matching a drawing and matching a category.

**What causes flatness problems after machining?**

Residual stress in the stock. Stress-relieved tempers exist for that reason and are the answer worth naming.

**How does anodising affect tolerance?**

It adds thickness, and hard anodising adds more. The machining allowance is part of the specification rather than a shop detail.
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Source: https://manufacturingseo.ai/materials/aluminum/
Last reviewed: 2026-08-10
Author: ManufacturingSEO.ai