Choosing Cutting Fluid: Turning Steel vs Aluminum

Functions

Cool, lubricate, flush chips, prevent rust. Wrong fluid = short tool life, poor finish, black corroded aluminum.

Two Types

• Emulsion (water-based): Cooling first, cost-effective for steel
• Neat oil: Lubrication first - tapping, reaming, tough alloys

By Material

• Steel (45#, 40Cr): Emulsion fine; higher concentration for finish
• Aluminum: Use neutral aluminum-specific fluid; alkaline emulsion corrodes and darkens it
• Stainless: EP oil or high-concentration emulsion to prevent smearing
• Cast iron: Dry or low concentration to avoid sludge

Management

• Check concentration with refractometer (emulsion 5-10%)
• Replace rancid fluid
• Separate aluminum chips before return

Huami Practice

Huami manages fluids by material - dedicated aluminum fluid with regular checks.