Is AISI 1045 steel Really Easy to Machine?

If you’re looking for a steel grade that combines strength with workability, AISI 1045 steel often comes up as a top choice. But how good is it really when it comes to machining?

The short answer: Quite good—under the right conditions.

AISI 1045 steel is a medium carbon steel with around 0.45% carbon content, offering a balance of mechanical strength and moderate hardness. This composition makes it significantly stronger than low-carbon steels, but still machinable using standard tools.

Its machinability rating is about 64% compared to B1112 (a benchmark material). In its hot-rolled or normalized state, AISI 1045 steel performs well in most machining operations—such as turning, milling, drilling, and tapping—with smooth chip formation and good surface finishes.

However, there are a few points to keep in mind:

Tool wear may increase if speeds and feeds are not optimized.
In the hardened condition, AISI 1045 steel becomes more difficult to machine, requiring carbide tools or pre-machining before heat treatment.
Using the right coolant and cutting parameters is key to extending tool life and ensuring precision.

AISI 1045 steel is not the easiest steel to machine, but it offers a very workable balance between strength and machinability—making it an excellent choice for applications like shafts, gears, and precision parts.