The metallurgy
Why this family exists
Free cutting steels are engineered around one goal: remove metal quickly and cleanly. Sulphur is added deliberately, forming manganese sulphide inclusions through the steel. Those inclusions act as internal stress raisers that break the chip into short, manageable pieces instead of long stringy swarf that wraps around the tool.
The practical result on a shop floor is dramatic: higher spindle speeds, longer tool life, better surface finish straight off the tool, and — most importantly for an automatic machine running unattended — chips that clear themselves instead of jamming the machine.
EN1A PB takes this further by adding lead, which smears at the cutting zone and acts as an internal lubricant. On high-speed automatics running multi-spindle bar work, the difference between EN1A and EN1A PB is measured in real parts per hour.
The grades
2 grades in this family
Side by side
Choosing within the family
| Property | EN1A | EN1A PB |
|---|---|---|
| Key advantage | Chips break short and clear themselves | Lead acts as an internal lubricant at the cutting edge |
| Machinability | 95 · Excellent | 145 · Excellent |
| Weldability | Not recommended | Not recommended |
| Condition supplied | Cold Drawn | Cold Drawn |
| Primary use | Nuts, bolts and fasteners | High-speed multi-spindle automatic turning |
Chemical composition and mechanical properties shown are as per the applicable standard and are indicative. Actual values for your consignment are certified in the Mill Test Certificate supplied with each dispatch. Available sizes and tolerances are confirmed at the time of enquiry.
Other families
Looking for something else?
Low Carbon
Weldable, formable and economical — the workhorse grades for general engineering.
MS · SAE 1018
Medium Carbon
Through-hardenable strength for shafts, axles and spindles that carry real load.
EN8 · EN8D · EN8M
Case Hardening
Hard surface, tough core — the alloy grades behind gears, pinions and transmissions.
16MnCr5 · 16MnCr5H · 20MnCr5
Need a free cutting grade?
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