Steel 1118 CARB-QT
Heat-treated state
AISI/SAE 1118 · UNS G11180
CARB-QT = carburized, Quenched & Tempered
Choose for wear surfaces: hard 58–62 HRC case over a tough ~30 HRC core; case depth typically 0.5–1.5 mm.
Values for the CARB-QT condition
Other 1118 tempers and conditions
1118 is listed in 6 conditions; see the grade overview at 1118.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled | Cheapest form for parts fully machined all over or for subsequent carburizing. | 250 | 450 | 32 | 131 HB | — |
Solution annealed | Softest condition for cold forming, deep drawing or severe upsetting before hardening. | 285 | 450 | 35 | 131 HB | 10.5 % IACS |
Normalized | Uniform fine grain before carburizing or heavy machining of forgings. | 320 | 480 | 33 | 143 HB | 10.5 % IACS |
Cold Drawn, Stress Relieved | Pick when unbalanced machining would otherwise bow the part; keeps most cold-drawn strength. | 415 | 505 | 18 | 143 HB | 10.5 % IACS |
CDDefault Cold drawn | Standard stocked condition: good size tolerance, straightness and the best chip control for screw-machine work. | 450 | 525 | 15 | 149 HB | — |
CARB-QTThis page Carburized, Quenched & Tempered | Choose for wear surfaces: hard 58–62 HRC case over a tough ~30 HRC core; case depth typically 0.5–1.5 mm. | 550 | 760 | 14 | 60 HRC | — |
What is 1118 CARB-QT?
1118 CARB-QT is 1118 heat treated to CARB-QT — choose for wear surfaces: hard 58–62 HRC case over a tough ~30 HRC core; case depth typically 0.5–1.5 mm. 1118 CARB-QT has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 71% of steel grades. Elongation at break is 14% and the elastic modulus is 200 GPa (29 Msi). 1118 CARB-QT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). CD is the default condition FabDigit quotes; CARB-QT is available on request or by drawing note.
Advantages
- Conducts heat well — 51.9 W/m·K (30 BTU/hr·ft·°F), better than 96% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High electrical conductivity — 10.5 % IACS, better than 89% of steel grades
Limitations
- Hard to polish — 35/100, worse than 99% of steel grades
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Difficult to machine — 25/100, worse than 93% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
1118 CARB-QT properties
Typical room-temperature values for 1118 CARB-QT; 12 are specific to this condition. Other listed values are 1118 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
1118 CARB-QT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical13
1118 CARB-QT has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 71% of steel grades. Elongation at break is 14% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1118 CARB-QT is rated for continuous service to 180°C (356 °F). It conducts heat at 51.9 W/m·K (30 BTU/hr·ft·°F), better than 96% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
1118 CARB-QT conducts electricity at 10.5 % IACS, better than 89% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 1118 CARB-QT 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
1118 CARB-QT's machinability is poor (25/100, worse than 93% of steel grades); weldability fair (45/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1118 CARB-QT
Is 1118 easy to machine?
Excellent — 90 % of 1212; run high speeds with sulfurized or soluble oil, expect short broken chips and long tool life.
Can 1118 be welded?
Marginal — high sulfur promotes hot cracking and porosity; if unavoidable use low-hydrogen filler, preheat 100–150 °C and low heat input.
Can 1118 be formed, bent or molded?
Moderate cold formability in the annealed state; sulfide stringers cause poor transverse ductility, so avoid tight transverse bends and severe cold heading.
What surface finishes work on 1118?
Not anodizable; protect with zinc or nickel plating, black oxide, phosphate + oil, or paint. MnS inclusions limit mirror polishing and can pit in plating baths.
1118 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 |
|---|---|---|
| CSAE J403 / ASTM A29 heat analysis | 0.14 – 0.2 | 0.17 |
| Mncombines with S as MnS for chip breaking | 1.3 – 1.6 | 1.45 |
| P | ≤ 0.04 | 0.02 |
| Sresulfurized, intentional | 0.08 – 0.13 | 0.1 |
| Sinot normally specified for resulfurized grades | ≤ 0.1 | 0.05 |
| Fe | balance | — |
1118 CARB-QT — frequently asked
What is 1118 CARB-QT used for?
1118 CARB-QT is typically used for carburized pins, shafts, gears and fasteners. In short: free-machining carburizing steel; about 90 % of 1212; case-hardens with good core.
What is the yield strength of 1118 CARB-QT?
1118 CARB-QT has a typical yield strength of 550 MPa (79.8 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 71% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 1118 CARB-QT easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of steel grades). Excellent — 90 % of 1212; run high speeds with sulfurized or soluble oil, expect short broken chips and long tool life.
Can 1118 CARB-QT be welded?
With care — weldability is rated fair (45/100). Marginal — high sulfur promotes hot cracking and porosity; if unavoidable use low-hydrogen filler, preheat 100–150 °C and low heat input.
What surface finishes work on 1118 CARB-QT?
Not anodizable; protect with zinc or nickel plating, black oxide, phosphate + oil, or paint. MnS inclusions limit mirror polishing and can pit in plating baths.
Can 1118 CARB-QT be formed, bent or molded?
Moderate cold formability in the annealed state; sulfide stringers cause poor transverse ductility, so avoid tight transverse bends and severe cold heading.
What is the maximum service temperature of 1118 CARB-QT?
1118 CARB-QT 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 1118-CD and 1118-HR?
CD is the default condition — standard stocked condition: good size tolerance, straightness and the best chip control for screw-machine work. HR: cheapest form for parts fully machined all over or for subsequent carburizing. Yield strength is 450 MPa in CD versus 250 MPa in HR.
Sources
- SAE J403 — Chemical Compositions of SAE Carbon Steels — SAE International (2014)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements — ASTM (2020)
- ASTM A108 — Steel Bar, Carbon and Alloy, Cold-Finished — ASTM (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.16 — Machining (machinability ratings) — ASM International (1989)
- MatWeb / MMPDS typical carbon-steel property tables — MatWeb LLC (2023)
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.