Common Metals: Steel, Stainless, Aluminum & Brass

Plain-English Summary

Understand practical differences between common metals used in industrial work, including steel, stainless steel, aluminum, brass, machinability, corrosion, welding, wear, and field cautions.

Why It Matters

Choosing or misidentifying material can create serious problems. A repair that works in mild steel may fail in aluminum. Stainless can lose corrosion resistance if contaminated or overheated. Brass may machine easily but lack required strength.

Field Rule of Thumb

Do not pick a material only because it is available. Ask what the part does, what it contacts, what environment it sees, and whether the material is specified by drawing, OEM, code, or customer requirement.

Core Concept

Carbon steel is common, strong, and weldable in many general uses. Stainless supports corrosion resistance and cleanability. Aluminum is lightweight and often machinable. Brass/bronze/copper alloys are common for bushings, fittings, wear surfaces, and conductivity.

Worked Example

A washdown conveyor bracket breaks. Mild steel is available, but before replacing stainless with mild steel, verify food-contact, washdown, corrosion, finish, customer, and site standards. The fastest material may not be the correct material.

Common Mistakes

• Calling all steel the same.
• Assuming stainless cannot rust.
• Using aluminum like steel.
• Ignoring galvanic corrosion.
• Welding unknown material.
• Ignoring environment.

First Checks / Troubleshooting Flow

1. Check drawing, parts list, OEM manual, or records.
2. Look for markings or certificates.
3. Identify function, load, wear, temperature, chemicals, corrosion, and sanitation exposure.
4. Check forming, welding, machining, threading, or finishing requirements.
5. Confirm whether substitution is allowed.