Free-Cutting Steels / LEADFREE
Lead-Free Free-Cutting Steels
Lead-free free-cutting steels are grades developed for environmentally friendly production requirements. They replace leaded alternatives in RoHS-compliant applications.
Technical Specifications
Key Features
- Good machinability (lead-free formulation)
- RoHS and REACH compliant
- Clean chip formation
- Acceptable tool life
- Good surface finish quality
- Suitable for high-volume production
- Available in round, hexagon, and square profiles
- Environmentally friendly production processes
Applications
- RoHS-compliant electronic component parts
- Automotive industry fasteners
- CNC machined general machine parts
- Bolt, nut, and screw production
- Pin and bushing manufacturing
- Hydraulic and pneumatic fittings
- Food machinery parts
- Medical device components
Dimension Table
| Form | Size Range (mm) | Tolerance | Standard Length |
|---|---|---|---|
| Round | 2 - 120 mm | h9, h10, h11 | 3 m (min 2.5 m, max 6 m) |
| Hexagon | 5 - 80 mm | h9, h10, h11 | 3 m (min 2.5 m, max 6 m) |
| Square | 5 - 70 mm | h9, h10, h11 | 3 m (min 2.5 m, max 6 m) |
Technical Notes
- 0111SMn30 (1.0715) is the most commonly used lead-free free-cutting steel grade.
- 02Manganese sulfide (MnS) inclusions serve the chip-breaking function.
- 03Slightly lower cutting speeds should be applied compared to leaded grades.
- 04EN ISO 683-4 defines hot-rolled production requirements.
- 05EN 10277 specifies cold-drawn mechanical properties.
- 0644SMn28 (1.0762) is suitable for applications requiring higher strength.
- 07Lead-free grades are mandatory in food and medical industry sectors.
Other Types
What is free-cutting steel?
Free-cutting (free-machining) steel has deliberately raised sulphur (0.10–0.35% S) for high-speed machining. MnS inclusions break the chip, extending tool life and improving surface finish. The most common grades are 11SMn30 (lead-free) and 11SMnPb30 (leaded, EN 10087). It is the standard choice for bushings, pins, nipples and fittings mass-produced on automatic and CNC lathes.
Leaded vs lead-free and the trade-offs
Lead (0.15–0.35% Pb) acts as a lubricant in the cutting zone, further improving finish and tool life (11SMnPb30); however, health and environmental regulations are pushing lead-free alternatives (11SMn30 and bismuth/tellurium-treated specials). The trade-off of free-cutting steel: high sulphur reduces weldability and transverse toughness — so it is not used for welded or safety-critical parts. Where quench and tempering is needed, medium-carbon free-cutting grades such as 35S20 / 36SMn14 are selected. Delivery condition: free-cutting steel is almost always supplied as a cold drawn profile (round, square or flat, h9–h11 to EN 10277). This is not a commercial detail but a working requirement — on a bar-fed automatic lathe, sectional consistency and surface finish govern the stability of the setup and the tool life; a hot-rolled bar with scale and wide tolerances would let dimensions drift from part to part. The grade decides machinability, the drawing process decides consistency: the two choices are made together.
Frequently Asked Questions
What is the difference between 11SMn30 and 11SMnPb30?+
Both are high-sulphur free-cutting steels; 11SMnPb30 additionally contains 0.15–0.35% lead for better finish and tool life, but lead-free 11SMn30 is increasingly preferred due to RoHS/environmental limits.
Can free-cutting steel be welded?+
Not recommended. High sulphur causes hot cracking; use standard carbon steels for welded parts.
Where is free-cutting steel used?+
Bushings, shafts, nipples, unions and threaded fittings mass-produced on automatic/CNC lathes — high-volume machined parts.
Can free-cutting steel be hardened?+
Low-carbon grades (11SMn30) can only be case-hardened; if through-hardening is needed, choose medium-carbon grades like 35S20/36SMn14.
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