Steel SUM24L
JIS SUM24L
SUM24L is a leaded resulfurized free-cutting carbon steel, the Japanese equivalent of AISI 12L14, with roughly 0.3% sulfur plus free lead added to break chips and extend tool life.
Values for the HR condition
SUM24L tempers and conditions
SUM24L is supplied in 4 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
subcritical / spheroidize annealed | Pick for cold forming such as riveting, flanging and roll forming, or to remove cold-drawing residual stress; strength is lowest at 370 MPa tensile with 25 % elongation. | 220 | 370 | 25 | 110 HB | — |
HRDefault Hot rolled | Pick for large diameters or when further machining and heat treatment follow; it is the lowest-cost form but has the poorest dimensional tolerance and surface condition. | 235 | 395 | 22 | 121 HB | — |
Cold rolled | Choose for cold rolled flats, squares and special sections needing accurate flat dimensions; properties approach cold drawn at 395 MPa yield, with formability reduced to 32. | 395 | 520 | 12 | 155 HB | 10 % IACS |
Cold drawn | Use as the standard stock state for automatic lathe work: close diameter tolerance, smooth surface and the best chip breaking; most bar inventory is supplied as-drawn. | 415 | 540 | 10 | 163 HB | — |
Supply forms, finishes and certifications
Ways SUM24L is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
TGP | Turned, Ground & Polished bar | Surface finish |
What is SUM24L?
SUM24L is a leaded resulfurized free-cutting carbon steel, the Japanese equivalent of AISI 12L14, with roughly 0.3% sulfur plus free lead added to break chips and extend tool life. It is used for high-volume work on Swiss-type and multi-spindle automatic lathes and is stocked as hot-rolled, cold-rolled, cold-drawn, annealed and TGP bar at 235 MPa yield, 395 MPa tensile, 22% elongation and 121 HB. It is effectively unweldable, forms poorly and has no corrosion resistance, and the lead content brings RoHS/REACH restrictions; SUM23 (AISI 1215) is the nearest lead-free alternative. SUM24L has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 92% of steel grades. It melts at 1,420°C (2,588 °F). SUM24L has a yield strength of 235 MPa (34.1 ksi) and a tensile strength of 395 MPa (57.3 ksi) — weaker than 96% of steel grades. Elongation at break is 22% and the elastic modulus is 200 GPa (29 Msi).
What is SUM24L used for?
- Screw machine parts
- Hydraulic and pneumatic fittings
- Threaded bushings and inserts
- Connector and sensor bodies
- Valve bodies and spool housings
- Light-duty pins and spacers
- Automotive small turned components
Advantages
- Easy to machine — 94/100, better than 100% of steel grades
- Conducts heat well — 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
Limitations
- Difficult to weld — 10/100, worse than 99% of steel grades
- Low strength — 235 MPa (34.1 ksi), worse than 96% of steel grades
- Limited service temperature — 280°C (536 °F), worse than 82% of steel grades
SUM24L properties
Typical room-temperature values for SUM24L-HR; bars are the position among steel grades.
Physical3
SUM24L has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 92% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical13
SUM24L has a yield strength of 235 MPa (34.1 ksi) and a tensile strength of 395 MPa (57.3 ksi) — weaker than 96% of steel grades. Elongation at break is 22% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
SUM24L is rated for continuous service to 280°C (536 °F). It conducts heat at 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
SUM24L conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of SUM24L takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 35%.
Manufacturability7
SUM24L's machinability is excellent (94/100, better than 100% of steel grades); weldability not recommended (10/100); formability fair (45/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. SUM24L is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SUM24L
Is SUM24L easy to machine?
The reference grade for free cutting: run high-speed Swiss and turret lathes dry or with oil mist, with good chip breaking, long tool life and surface finish down to Ra 0.4 µm. Avoid it where the part is sensitive to low-toughness fracture.
Can SUM24L be welded?
Effectively unweldable: 0.3% sulfur and free lead cause severe hot cracking and lead fume hazard. Limit joining to small brazed areas on non-structural features or use structural adhesive.
Can SUM24L be formed, bent or molded?
Cold bending and flanging capability is poor because sulfide inclusions split along the rolling direction; if forming is required, use annealed stock and the largest possible bend radii. Knurling and thread rolling are practical.
Manufacturability
The process limits FabDigit applies to SUM24L. Every SUM24L part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Excellent94 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
SUM24L chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CJIS G4804 upper limit | ≤ 0.15 | 0.09 |
| Mn | 0.85 – 1.15 | 1 |
| Padded intentionally to improve machinability | 0.04 – 0.09 | 0.06 |
| SMnS inclusions break chips | 0.26 – 0.35 | 0.3 |
| Pbfree lead gives internal lubrication | 0.1 – 0.35 | 0.2 |
| Siusually not specified / low silicon | ≤ 0.1 | |
| Fe | balance |
What surface finishes work on SUM24L?
Black oxide, phosphate plus oil, zinc plating and nickel plating are the usual protective options. Remove all lead-bearing chip residue before plating, and check RoHS/REACH and export restrictions on the leaded composition.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel SUM24L in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- 12L14
How much does SUM24L cost?
SUM24L is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
SUM24L — frequently asked
What is SUM24L used for?
SUM24L is typically used for screw machine parts, hydraulic and pneumatic fittings, threaded bushings and inserts, connector and sensor bodies, valve bodies and spool housings and light-duty pins and spacers. In short: leaded free-machining bar.
What is the yield strength of SUM24L?
SUM24L has a typical yield strength of 235 MPa (34.1 ksi) and a tensile strength of 395 MPa (57.3 ksi) — weaker than 96% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is SUM24L easy to machine?
Yes — machinability is rated excellent (94/100, better than 100% of steel grades). The reference grade for free cutting: run high-speed Swiss and turret lathes dry or with oil mist, with good chip breaking, long tool life and surface finish down to Ra 0.4 µm. Avoid it where the part is sensitive to low-toughness fracture.
Can SUM24L be welded?
Not readily — weldability is rated not recommended (10/100). Effectively unweldable: 0.3% sulfur and free lead cause severe hot cracking and lead fume hazard. Limit joining to small brazed areas on non-structural features or use structural adhesive.
What surface finishes work on SUM24L?
Black oxide, phosphate plus oil, zinc plating and nickel plating are the usual protective options. Remove all lead-bearing chip residue before plating, and check RoHS/REACH and export restrictions on the leaded composition.
Can SUM24L be formed, bent or molded?
Cold bending and flanging capability is poor because sulfide inclusions split along the rolling direction; if forming is required, use annealed stock and the largest possible bend radii. Knurling and thread rolling are practical.
What is the maximum service temperature of SUM24L?
SUM24L is rated for continuous use to about 280°C (536 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SUM24L-HR and SUM24L-CD?
HR is the default condition — pick for large diameters or when further machining and heat treatment follow; it is the lowest-cost form but has the poorest dimensional tolerance and surface condition. CD: use as the standard stock state for automatic lathe work: close diameter tolerance, smooth surface and the best chip breaking; most bar inventory is supplied as-drawn. Yield strength is 235 MPa in HR versus 415 MPa in CD.
How much does SUM24L cost?
SUM24L is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in SUM24L?
Yes — SUM24L is available for CNC machining; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A108 / SAE J403 (12L14) — ASTM / SAE (2018)
- GB/T 8731 (Y15Pb) (2008)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Free-cutting steel bar datasheets (12L14 / SUM24L) — Nippon Steel / / Niagara LaSalle (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.