The steels for high-speed machining, commonly called free-cutting steels, have been specially designed to be machined by chip removal with high productivity.
Free-cutting steels – which are commonly used in many mass production fields such as the automobile industry and household appliances – contain sulphur and some other elements, including tellurium, bismuth and lead, which promote machinability.
In particular, the sulphur ensures the fragmentation of the chip, lead reduces the friction between the tool and piece, extending the life of the tools, and the tellurium and bismuth further accentuate these characteristics.
Free-cutting steels are usually supplied in bars or rolls without heat treatment; however, some of these can be tempered, normalized or annealed before finishing.
Free-Cutting Steels Not Intended For Heat Treatment
Free-cutting steels not intended for heat treatment are steels in which the low carbon content allows the maximum workability to be achieved and are therefore suitable for high-speed machining.
Among the most common in the free-cutting steel category, they are designed to be implemented at the thermal state in which they are provided, without further treatments. It is increasingly customary to also use these steels for some thermochemical treatments of surface hardening: in this case, in-depth knowledge of the process and some precautions is necessary.
Rodacciai offers a range of free-cutting steels not intended for heat treatment that is able to satisfy various machining requirements.
Free-Cutting Steels Carburized
Pieces obtained from carburized free-cutting steels with low carbon content can be subjected, after machining, to surface hardening treatments through carburizing or other thermochemical treatments.
Free-Cutting Steels Quenched And Tempered
Quenched and tempered free-cutting steels have a higher carbon content than other free-cutting steels while maintaining good machinability thanks to the presence of sulphur in smaller quantities. This type of steel can be prepared with quenching and tempering before drawing or peeling so as to be able to heat-treat the pieces after machining.
When quenched and tempered, these steels have elevated mechanical characteristics and can also be used for parts that require more excellent resistance and toughness than those of steels without heat treatment
| |
App |
Profile |
Range [mm] |
Surface |
Tolerance |
| Bars |
Rolled |
Round |
20-105 |
Raw, Peeled Iron Product |
- |
| Drawn |
Round
Hexagonal
Square Special |
2-80
4-80
4-70 |
Polished |
ISA
h9
h10
h11 |
Peeled
-
Rolled |
Round |
20-100 |
Polished |
ISA
h9
h10
h11 |
| Ground |
Round |
3-100 |
Polished |
ISA
h7
h8
h9
h10
h11 |
| Coils |
Drawn |
Round
Hexagonal
Square Special |
2-22
3-12
4-12 |
Polished, Phosphated |
ISA
h9
h10
h11 |
