Guide
Should a turned part be specified in 12L14 or 1215 free-machining steel?
12L14 is a low-carbon, resulfurized and rephosphorized free-machining steel with lead added to the melt, and 1215 is the same steel family without the lead. Both are bought as cold-finished bar for high-volume turned parts such as fittings, bushings, spacers and pins, and the choice between them comes down to machinability on one side and lead rules, welding and forming on the other.
By Saola Manufacturing engineering team · Published · Updated
This guide compares the two grades the way a design or sourcing engineer has to decide between them: what the chemistry says, what lead does in the cut, which regulations care about lead in steel, and what each grade tolerates after machining, from plating to crimping. It ends with how to write the material callout so that a shop overseas buys the bar you meant. Compositions come from the published ASTM grade designations; the regulatory points link to the official texts, so check them against the current consolidated version before you sign a declaration.
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What is the chemical difference between 12L14 and 1215?
The only designed difference is lead: 12L14 adds a controlled lead range on top of a sulfur and phosphorus level that both grades share, while 1215 has no lead addition. The “L” in the grade name is the AISI and SAE marker for a leaded steel.
| Element | 1215 | 12L14 | What it does in the cut |
|---|---|---|---|
| Carbon | 0.09 max | 0.15 max | Kept low so the steel stays soft and cuts cleanly |
| Manganese | 0.75–1.05 | 0.85–1.15 | Combines with sulfur to form manganese sulfide inclusions |
| Phosphorus | 0.04–0.09 | 0.04–0.09 | Hardens the ferrite slightly so chips break instead of smearing |
| Sulfur | 0.26–0.35 | 0.26–0.35 | Source of the sulfide stringers that break chips |
| Lead | not added | 0.15–0.35 | Acts as a lubricant at the tool edge |
Read across the rows and the two grades are nearly the same steel. Sulfur, phosphorus and manganese are the free-machining package in both; 12L14 simply runs a slightly wider carbon and manganese window and carries the lead. Neither grade is a structural steel. Both are chosen because they turn fast and leave a clean surface, and both give up ductility, weldability and fatigue strength for it.
Mechanical properties for cold-drawn bar depend on size and on how much the mill reduced it, which is why ASTM A108, the specification for cold-finished carbon and alloy bar, controls the bar condition while the chemistry comes from the grade designation. If a turned part carries load, state a minimum tensile or hardness requirement on the drawing rather than relying on the grade name.
Which grade machines better, 12L14 or 1215?
12L14 machines better: the lead forms a soft film at the tool edge that lowers cutting force and friction, so it tolerates higher speeds, breaks chips more reliably and leaves a finer surface than 1215. 1215 still machines far better than a plain low-carbon steel, because its sulfide inclusions do most of the chip-breaking work.
The difference shows up most on long-running parts with many features. On a multi-spindle or sliding-head lathe, a grade that holds tool life longer means fewer offsets and tool changes across a shift, and chips that break short are less likely to wrap a part or mark a finished diameter. For a small batch of simple parts, the gap between the two grades usually matters less than setup and inspection.
Surface finish follows the same pattern. Leaded steel tends to give a brighter as-turned surface on threads, grooves and form-tool profiles, which is one reason it is common in hydraulic and pneumatic fittings. If a part has a sealing face or a fine thread and no reason to avoid lead, 12L14 is the easier path to the finish.
Tolerance is a separate question from grade. Both steels turn to tight limits when the setup is right; on a CNC turning quote, tight features are reviewed part by part whatever the material.
Is 12L14 allowed under RoHS, REACH and Proposition 65?
12L14 depends on an exemption under EU RoHS and triggers disclosure duties under REACH and California’s Proposition 65, while 1215, with no lead added, normally avoids all three. Whether the exemption still covers your product is a question to check against the current annex, not an assumption to carry from an old declaration.
RoHS. Annex II of Directive 2011/65/EU limits lead to 0.1% by weight in each homogeneous material of electrical and electronic equipment. Annex III of the same directive carries exemption 6(a)-I, which allows lead as an alloying element in steel for machining purposes up to 0.35% by weight, and 12L14 is designed to sit inside that ceiling. The expiry dates printed next to exemptions 6(a) and 6(a)-I in the consolidated text have already passed. Article 5(5) of the directive keeps an exemption valid while a renewal application is pending until the Commission decides, so the practical status turns on the renewal decision, not the printed date. Check the Commission’s RoHS page for the current position before relying on it.
REACH. Lead was added to the ECHA Candidate List of substances of very high concern on 27 June 2018, as toxic for reproduction. Under Article 33 of REACH, a supplier of an article containing a Candidate List substance above 0.1% by weight must give recipients enough information for safe use, which is a routine line in a 12L14 part’s compliance file (ECHA).
Proposition 65. OEHHA lists lead as causing developmental and reproductive toxicity, and lead and lead compounds as causing cancer. A product sold in California that can expose people to lead may need a warning, which is why some OEMs ban leaded steel in anything a user handles.
For 1215, lead is not an intended element, so any value on a mill report is residual. If your customer wants proof, ask for lead to be reported on the mill test certificate rather than assuming it.
Can 12L14 or 1215 be welded or heat treated?
Neither grade is a good choice for a welded joint that carries load: the high sulfur in both promotes hot cracking and porosity in the weld, and 12L14 adds lead fumes to the problem. Both can be case hardened by carburizing, since their carbon is low, but through hardening does little for them.
Where a turned part must be welded to an assembly, the usual answers are to switch to a non-resulfurized low-carbon grade for that part, or to join it another way: a press fit, a thread, a crimp or a brazed joint qualified on samples. If 12L14 parts are welded or torch-heated anyway, the fumes contain lead, and in the US that brings the OSHA lead standard into play. Per 29 CFR 1910.1025, the permissible exposure limit is 50 µg/m³ averaged over an 8-hour period, with an action level of 30 µg/m³ (29 CFR 1910.1025).
Heat treatment deserves a note on the drawing too. Carburizing and nitriding are both possible on these grades, but leaded steels can lose ductility when stressed at elevated temperature, so a 12L14 part that runs hot in service, or that is heat-treated under load, should be tested before release. If the part only needs a hard wear surface, say so, and let the supplier propose the route. Where carburizing is the main reason for the grade choice, C1117 is a carburizing-grade free-machining steel worth comparing, and it is one of the grades this plant also turns from bar.
How do 12L14 and 1215 behave when plated or coated?
Both plate and coat like any low-carbon steel, with zinc plating, black oxide and nickel all common, but the sulfide inclusions that make them machine well can show up as small pits or dull spots on bright decorative finishes. Cleaning before plating matters more than on plain steel, because cutting oil and sulfide residue sit in those inclusions.
For a functional finish such as zinc with a clear or yellow passivate, the inclusions rarely matter. For a bright nickel or chrome finish on a visible surface, ask for a sample part plated before production and agree on what counts as a cosmetic defect. Lead in 12L14 does not stop plating, but it is one more reason to specify thorough cleaning and to keep the plating line informed of the grade.
Both grades are low-strength, so hydrogen embrittlement after acid cleaning and plating is usually a smaller concern than it is for hardened fasteners. If the part is case hardened before plating, that changes, and the drawing should call for a bake per the plating specification. The comparison of zinc plating against other finishes covers finish selection, and the surface finishing page lists the finishes available on turned steel parts.
Which grade is better for crimping, flaring or knurling?
Neither grade takes heavy cold forming well, because the sulfide stringers run along the bar and open into cracks when the metal is bent, flared or swaged hard across them. For light work such as a straight knurl, a shallow roll or a mild crimp, both usually cope, and 1215 is not reliably better than 12L14.
The failure mode to watch is splitting at the edge of a flare or crimp, which often appears only after plating or after the part has been in service for a while. If the design depends on a deformed feature, run the operation on samples from the actual bar heat before production, and inspect the formed area under magnification. If forming is severe, the right answer is usually a different grade, such as a non-resulfurized low-carbon steel, and a slower machining cycle.
Threads are a different case. Cut threads are normal on both grades. Thread rolling, which is a forming operation, works on these steels for modest thread forms, but it is worth confirming on samples if the part is thin-walled or the thread runs close to a shoulder.
How should the grade be written on a drawing sent to an overseas supplier?
Name the grade, the bar specification and the lead requirement together, for example “AISI 12L14 cold-drawn bar per ASTM A108” or “AISI 1215 per ASTM A108, no lead additions, lead to be reported on the mill certificate”. That single line tells the shop what to buy and what paperwork to keep.
Suppliers outside North America often buy bar made to European, ISO or Japanese free-cutting steel standards such as EN 10087, ISO 683-4 or JIS G4804, where the grade names are different and the compositions are close to the AISI grades but not identical. If you will accept an equivalent, say so and name it; if you will not, write “no substitution without written approval”. Either way, ask for the mill test certificate with the heat chemistry, so the lead and sulfur values can be checked against the table above.
For parts turned in Vietnam and shipped to the US or EU, three more lines save questions later:
- The compliance target. State whether the part must meet EU RoHS with or without the steel exemption, REACH Article 33 disclosure, or a customer ban on leaded steel.
- The finish and its specification. Plating on free-machining steel is easier to agree before the first lot than after it.
- Any forming or welding downstream. If the part will be crimped, flared or welded at your plant, say so, because it can change the grade recommendation.
The RFQ package guide covers the rest of what to send. When the drawing is ready, send it for a quote, and the reply will flag any grade, finish or tolerance question before pricing is final.
Frequently asked
Is 12L14 the same as 1215 with lead added?
Nearly. The sulfur and phosphorus ranges are the same, but the carbon and manganese windows differ slightly, so the two are separate grade designations with their own UNS numbers rather than one steel with an option.
Can I switch an existing 12L14 part to 1215 without redrawing it?
Usually the geometry does not need to change, but the drawing callout does, and machining cycles and tool life will differ. Run a first article in the new grade and check finish, threads and any formed features before approving the change.
Is 1215 automatically RoHS compliant?
It has no intentional lead, so it normally meets the lead limit without needing the steel exemption. Compliance is still shown by data, so ask for lead on the mill certificate if your customer requires a declaration.
Does 12L14 rust faster than 1215?
Neither grade is corrosion resistant, and both rust without a finish or oil. Plan on zinc plating, black oxide with oil, or another coating for any part that will see humidity.
What if the part must be lead-free and very easy to machine?
1215 is the usual starting point. Some mills also offer lead-free free-machining steels using other additions; if you consider one, name it on the drawing and ask for its published chemistry, because those grades are not interchangeable by name.
Sources
- ASTM A108-24, Standard Specification for Steel Bar, Carbon and Alloy, Cold-Finished, ASTM International, 2024
- ASTM A29/A29M-23, Standard Specification for General Requirements for Steel Bars, Carbon and Alloy, Hot-Wrought, ASTM International, 2023
- Directive 2011/65/EU (RoHS), consolidated text including Annex II, Annex III exemption 6(a)-I and Article 5(5), EUR-Lex, consolidated version of January 2025
- RoHS Directive overview and exemption status, European Commission, accessed September 2026
- Candidate List of substances of very high concern for Authorisation, entry for lead (EC 231-100-4), ECHA, included 2018, accessed September 2026
- Proposition 65 chemical listing: Lead, California OEHHA, listed 1987, accessed September 2026
- 29 CFR 1910.1025, Lead, US Code of Federal Regulations, accessed September 2026