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1215 Free-Machining Steel

1215 is a resulfurized and rephosphorized free-machining carbon steel built for one thing: fast, clean, high-volume machining. Its sulfur content forms manganese sulfide inclusions that break chips and lubricate the cut, giving a 4.5/5 machinability rating. With 540 MPa tensile and 415 MPa yield, it offers adequate strength for the screw-machine parts it is made for.

How 1215 Free-Machining Steel machines

At 4.5/5 it is among the best-machining steels available, ideal for high-speed automatic screw machines and CNC lathes. The sulfide inclusions produce short, manageable chips, low cutting forces, excellent surface finish, and long tool life, enabling fast cycle times and high throughput on small turned parts.

Manufacturing & processing

1215 is supplied as cold-drawn bar for turning and is the classic screw-machine stock. The same sulfur that aids machining hurts weldability and transverse ductility, so it is not for welded or highly stressed structural use. Corrosion resistance is low (1.5/5); parts are usually plated or oiled.

Typical applications

Used for high-volume turned components: fittings, bushings, fasteners, hose ends, nipples, connectors, and shafts where machining speed and finish dominate over maximum strength. Best where large quantities of small, precise turned parts must be produced quickly and economically.

When to choose it

Choose 1215 when machining throughput and finish drive cost on high-volume turned parts and the modest strength is sufficient. If the part must be welded or carry high stress, use a non-resulfurized grade like 1018. If you need higher strength with good machining, consider 1144 Stressproof.

Suitable surface finishes

Common finishes for 1215 Free-Machining Steel: zinc plating, black oxide, powder coating, nickel plating. Use the finish selector →

FAQ

What makes 1215 a free-machining steel?
Added sulfur (and phosphorus) form manganese sulfide inclusions that break chips into short pieces and lubricate the cutting edge. This gives low cutting forces, fine finishes, and long tool life — a 4.5/5 rating — making it ideal for high-speed automatic screw machines and CNC turning.
Can 1215 be welded?
It is not recommended. The high sulfur that makes 1215 machine so well promotes weld cracking and porosity and reduces transverse ductility. For parts that must be welded, choose a non-resulfurized grade such as 1018, which trades some machinability for far better weldability.
How does 1215 compare to 1144 Stressproof?
1215 machines slightly easier and is cheaper, suited to high-volume small turned parts. 1144 Stressproof offers much higher strength (690 vs 540 MPa tensile) plus stress-relieved dimensional stability for precision shafting. Pick 1215 for throughput on light parts, 1144 when strength and straightness matter.

Property values are typical/nominal for early guidance and vary by temper, grade, supplier and heat treatment. Confirm critical specs against a certified datasheet or with an mfgiq engineer.