Steel S15C-CH (Carburized and hardened)
Heat-treated state
JIS S15C
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.
Values for the CH condition
Other S15C tempers and conditions
S15C is listed in 6 conditions; see the grade overview at S15C.
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 |
CHThis page 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-CH?
S15C-CH is S15C heat treated to CH — 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. S15C-CH has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 76% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi). S15C-CH 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). N is the default condition FabDigit quotes; CH is available on request or by drawing note.
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
- 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
Limitations
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Difficult to machine — 15/100, worse than 98% of steel grades
- Low strength — 340 MPa (49.3 ksi), worse than 76% of steel grades
S15C-CH properties
Typical room-temperature values for S15C-CH; 11 are specific to this condition. Other listed values are S15C reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
S15C-CH 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-CH has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 76% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
S15C-CH is rated for continuous service to 180°C (356 °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-CH 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-CH 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-CH's machinability is poor (15/100, worse than 98% of steel grades); weldability excellent (95/100); formability excellent (90/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S15C-CH
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.
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.
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 | — |
S15C-CH — frequently asked
What is S15C-CH used for?
S15C-CH 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-CH?
S15C-CH has a typical yield strength of 340 MPa (49.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 76% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is S15C-CH easy to machine?
Not especially — machinability is rated poor (15/100, worse than 98% 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-CH 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-CH?
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-CH 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-CH?
S15C-CH is rated for continuous use to about 180°C (356 °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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.