Steel 1115 CARB
Heat-treated state
AISI/SAE 1115 · UNS G11150
CARB = carburized, Quenched & Tempered
Final condition for wear surfaces: hard martensitic case on a tough low-carbon core.
Values for the CARB condition
Other 1115 tempers and conditions
1115 is listed in 6 conditions; see the grade overview at 1115.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Use before heavy cold forming or when the softest, most stable structure is needed prior to carburizing. | 225 | 395 | 26 | 111 HB | — |
Hot rolled | Lowest-cost condition for larger sections that will be fully machined or later carburized. | 230 | 425 | 22 | 121 HB | — |
Normalized | Refines grain and homogenizes forgings/bar before carburizing or heavy machining. | 260 | 440 | 24 | 126 HB | — |
Cold Drawn, Stress Relieved | Choose when unbalanced machining causes distortion; keeps most cold-drawn strength with lower residual stress. | 380 | 460 | 18 | 137 HB | 10.8 % IACS |
CDDefault Cold drawn | Standard stocked condition for screw-machine work: good size tolerance, straightness and chip control. | 410 | 480 | 15 | 143 HB | — |
CARBThis page Carburized, Quenched & Tempered | Final condition for wear surfaces: hard martensitic case on a tough low-carbon core. | 420 | 620 | 12 | 60 HRC | — |
What is 1115 CARB?
1115 CARB is 1115 heat treated to CARB — final condition for wear surfaces: hard martensitic case on a tough low-carbon core. 1115 CARB has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 53% of steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi). 1115 CARB 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). CD is the default condition FabDigit quotes; CARB is available on request or by drawing note.
Advantages
- High electrical conductivity — 10.8 % IACS, better than 94% 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 formability — 5/100, worse than 99% of steel grades
- Difficult to machine — 15/100, worse than 98% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
1115 CARB properties
Typical room-temperature values for 1115 CARB; 11 are specific to this condition. Other listed values are 1115 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
1115 CARB 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).
Mechanical14
1115 CARB has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 53% of steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1115 CARB 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
1115 CARB conducts electricity at 10.8 % IACS, better than 94% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 1115 CARB takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
1115 CARB's machinability is poor (15/100, worse than 98% of steel grades); weldability fair (40/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1115 CARB
Is 1115 easy to machine?
Excellent for high-volume screw-machine and CNC turning (~85% of AISI 1212); MnS gives short chips and good tool life, but avoid very fine finishes where inclusion pull-out matters.
Can 1115 be welded?
Weldable only with care — high sulfur promotes hot cracking and porosity; use low-hydrogen basic electrodes, low heat input and avoid critical structural welds.
Can 1115 be formed, bent or molded?
Moderate cold formability in annealed/hot-rolled bar; sulfide stringers reduce transverse ductility so avoid tight transverse bends and severe heading.
What surface finishes work on 1115?
No anodizing; protect with zinc/nickel plating, black oxide, phosphate-and-oil or paint. Case carburizing raises surface hardness for wear applications.
1115 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 |
|---|---|---|
| C | 0.13 – 0.18 | 0.16 |
| Mn | 0.6 – 0.9 | 0.75 |
| Sresulfurized for machinability (MnS inclusions) | 0.08 – 0.13 | 0.11 |
| P | ≤ 0.04 | 0.02 |
| Sinot specified for resulfurized bar grades; residual only | — | — |
| Fe | balance | — |
1115 CARB — frequently asked
What is 1115 CARB used for?
1115 CARB is typically used for gears, studs and carburized pins. In short: case-hardenable free-machining steel; about 85% of 1212; tough core after carburizing.
What is the yield strength of 1115 CARB?
1115 CARB has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 1115 CARB easy to machine?
Not especially — machinability is rated poor (15/100, worse than 98% of steel grades). Excellent for high-volume screw-machine and CNC turning (~85% of AISI 1212); MnS gives short chips and good tool life, but avoid very fine finishes where inclusion pull-out matters.
Can 1115 CARB be welded?
With care — weldability is rated fair (40/100). Weldable only with care — high sulfur promotes hot cracking and porosity; use low-hydrogen basic electrodes, low heat input and avoid critical structural welds.
What surface finishes work on 1115 CARB?
No anodizing; protect with zinc/nickel plating, black oxide, phosphate-and-oil or paint. Case carburizing raises surface hardness for wear applications.
Can 1115 CARB be formed, bent or molded?
Moderate cold formability in annealed/hot-rolled bar; sulfide stringers reduce transverse ductility so avoid tight transverse bends and severe heading.
What is the maximum service temperature of 1115 CARB?
1115 CARB 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 1115-CD and 1115-A?
CD is the default condition — standard stocked condition for screw-machine work: good size tolerance, straightness and chip control. A: use before heavy cold forming or when the softest, most stable structure is needed prior to carburizing. Yield strength is 410 MPa in CD versus 225 MPa in A.
Sources
- SAE J403 — Chemical Compositions of SAE Carbon Steels — SAE International (2014)
- ASTM A108 — Steel Bar, Carbon and Alloy, Cold-Finished — ASTM (2018)
- ASTM A576 — Steel Bars, Carbon, Hot-Wrought, Special Quality — ASTM (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- ASM Handbook Vol.4 — Heat Treating (carburizing of low-carbon steels) — ASM International (1991)
- GB/T 8731 (Y15 comparison grade) — SAC (2008)
- Mysteel / SMM — Mysteel (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.