Steel S15C
JIS S15C
S15C is a Japanese plain low-carbon machine-structural steel (≤0.25 % C, nominally about 0.15 % C) essentially equivalent to SAE 1015.
Reference datasheet — S15C is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the N condition
S15C tempers and conditions
S15C is supplied in 6 conditions, soft to hard. N is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition — pick for severe cold forming, deep drawing or heavy cold heading before final heat treatment. | 230 | 385 | 35 | 101 HB | — |
Hot rolled | Cheapest as-supplied condition for weldments, brackets and machined parts where dimensional/finish tolerance is not critical. | 250 | 400 | 32 | 111 HB | — |
NDefault Normalized | Standard JIS G4051 delivery condition — uniform fine ferrite/pearlite, best all-round toughness and machinability for general structural parts. | 260 | 420 | 30 | 121 HB | — |
Quenched and tempered | Modest strength lift on thin sections only — low hardenability means little benefit above ~25 mm diameter. | 310 | 460 | 28 | 135 HB | 11 % IACS |
Carburized and hardened | The classic use of S15C — 0.3–1.2 mm hard case (58–62 HRC) over a tough low-carbon core for pins, bushings, light gears and cams. | 340 | 520 | 18 | 60 HRC | — |
Cold drawn | Choose for close tolerance, bright finish shafting and screw-machine work where higher yield strength and chip control are wanted. | 400 | 470 | 18 | 131 HB | — |
What is S15C?
S15C is a Japanese plain low-carbon machine-structural steel (≤0.25 % C, nominally about 0.15 % C) essentially equivalent to SAE 1015. It is used for lightly stressed machine parts and for carburized components, and is available hot-rolled, annealed, normalized and cold-drawn as bar, plate and strip. Hot-rolled properties are 260 MPa yield, 420 MPa tensile and 30 % elongation at 121 HB, with a formability score of 90 and excellent weldability at CEV ≈ 0.25. Strength is low and the steel will not through-harden, so case harden wear surfaces or step up to S25C when more core strength is required. S15C has a density of 7.86 g/cm³ (0.284 lb/in³), heavier than 90% of steel grades. It melts at 1,490°C (2,714 °F). S15C has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 92% of steel grades. Elongation at break is 30% and the elastic modulus is 205 GPa (29.7 Msi).
What is S15C used for?
- carburized pins
- shafts
- bolts
- machine parts
Advantages
- High electrical conductivity — 11 % IACS, better than 98% of steel grades
- Forms and bends easily — 90/100, better than 98% of steel grades
- Readily welded — 95/100, better than 97% of steel grades
- Ductile — tolerates forming and impact — 30%, better than 93% of steel grades
- Conducts heat well — 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
Limitations
- Low strength — 260 MPa (37.7 ksi), worse than 92% of steel grades
S15C properties
Typical room-temperature values for S15C-N; bars are the position among steel grades.
Physical3
S15C has a density of 7.86 g/cm³ (0.284 lb/in³), heavier than 90% of steel grades. It melts at 1,490°C (2,714 °F).
Mechanical15
S15C has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 92% of steel grades. Elongation at break is 30% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
S15C is rated for continuous service to 400°C (752 °F). It conducts heat at 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
S15C conducts electricity at 11 % IACS, better than 98% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of S15C takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability8
S15C's machinability is good (55/100, better than 62% of steel grades); weldability excellent (95/100); formability excellent (90/100).
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. S15C is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S15C
Is S15C easy to machine?
Soft and gummy — use sharp positive-rake tools, high surface speed and generous coolant to avoid built-up edge; normalize or cold draw first for better finish, or switch to a resulfurized grade for screw-machine work.
Can S15C be welded?
Excellent weldability by all arc, resistance and gas processes; CEV ≈ 0.25 so no preheat or PWHT is needed except on very heavy sections.
Can S15C be formed, bent or molded?
Very good cold formability — suitable for deep drawing, bending to tight radii and cold heading; hot forge at 1100–1250 °C and normalize afterwards.
S15C 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 G4051 | 0.13 – 0.18 | 0.15 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.3 – 0.6 | 0.45 |
| P | ≤ 0.03 | |
| S | ≤ 0.04 | |
| Curesidual, max | ≤ 0.3 | |
| Niresidual, max | ≤ 0.2 | |
| Crresidual, max; Ni+Cr ≤ 0.35 | ≤ 0.2 | |
| Fe | balance |
What surface finishes work on S15C?
No anodizing; protect with zinc/zinc-nickel plating, phosphate + oil, black oxide or paint. Takes a fair polish but soft surface scratches easily unless case hardened.
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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel S15C in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does S15C cost?
S15C 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.
S15C — frequently asked
What is S15C used for?
S15C is typically used for carburized pins, shafts, bolts and machine parts. In short: most weldable carbon steel; best-forming plain carbon grade; carburizing base steel.
What is the yield strength of S15C?
S15C has a typical yield strength of 260 MPa (37.7 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 92% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is S15C easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Soft and gummy — use sharp positive-rake tools, high surface speed and generous coolant to avoid built-up edge; normalize or cold draw first for better finish, or switch to a resulfurized grade for screw-machine work.
Can S15C be welded?
Yes — weldability is rated excellent (95/100). Excellent weldability by all arc, resistance and gas processes; CEV ≈ 0.25 so no preheat or PWHT is needed except on very heavy sections.
What surface finishes work on S15C?
No anodizing; protect with zinc/zinc-nickel plating, phosphate + oil, black oxide or paint. Takes a fair polish but soft surface scratches easily unless case hardened.
Can S15C be formed, bent or molded?
Very good cold formability — suitable for deep drawing, bending to tight radii and cold heading; hot forge at 1100–1250 °C and normalize afterwards.
What is the maximum service temperature of S15C?
S15C is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between S15C-N and S15C-CD?
N is the default condition — standard JIS G4051 delivery condition — uniform fine ferrite/pearlite, best all-round toughness and machinability for general structural parts. CD: choose for close tolerance, bright finish shafting and screw-machine work where higher yield strength and chip control are wanted. Yield strength is 260 MPa in N versus 400 MPa in CD.
How much does S15C cost?
S15C 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.
Sources
- JIS G 4051 — Carbon steels for machine structural use — JSA (2016)
- SAE J403 / ASTM A29 — Carbon steel bars (1015) — SAE / ASTM (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Machinery's Handbook (machinability ratings) — Industrial Press (2020)
- Mysteel / 1688 (2025)
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.