Steel 1120 CARB-QT
Heat-treated state
AISI/SAE 1120 · UNS G11200
CARB-QT = carburized, Quenched and Tempered
Choose for wear surfaces: hard 0.3–1.0 mm case on a tough, machinable low-carbon core.
Values for the CARB-QT condition
Other 1120 tempers and conditions
1120 is listed in 6 conditions; see the grade overview at 1120.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition for heavy cold forming, heading or deep boring before hardening. | 220 | 395 | 30 | 111 HB | 10.8 % IACS |
Hot rolled | Lowest-cost bar for parts that will be fully machined or subsequently case hardened. | 240 | 435 | 26 | 126 HB | — |
Normalized | Uniform fine grain structure after forging; better toughness consistency than as-rolled. | 255 | 450 | 27 | 131 HB | 10.5 % IACS |
Cold Drawn, Stress Relieved | Pick when parts machine asymmetrically and residual-stress distortion must be minimised. | 360 | 455 | 18 | 137 HB | 10.5 % IACS |
CDDefault Cold drawn | Standard stocked condition: good size tolerance, straightness and the best chip control on screw machines. | 395 | 470 | 15.5 | 143 HB | — |
CARB-QTThis page Carburized, Quenched and Tempered | Choose for wear surfaces: hard 0.3–1.0 mm case on a tough, machinable low-carbon core. | 400 | 620 | 14 | 60 HRC | — |
What is 1120 CARB-QT?
1120 CARB-QT is 1120 heat treated to CARB-QT — choose for wear surfaces: hard 0.3–1.0 mm case on a tough, machinable low-carbon core. 1120 CARB-QT has a yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Elongation at break is 14% and the elastic modulus is 200 GPa (29 Msi). 1120 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 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
- High electrical conductivity — 10.5 % IACS, better than 89% of steel grades
Limitations
- Limited formability — 5/100, worse than 99% of steel grades
- Hard to polish — 40/100, worse than 96% of steel grades
- Difficult to machine — 25/100, worse than 93% of steel grades
- Difficult to weld — 15/100, worse than 91% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
1120 CARB-QT properties
Typical room-temperature values for 1120 CARB-QT; 12 are specific to this condition. Other listed values are 1120 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
1120 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).
Mechanical14
1120 CARB-QT has a yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Elongation at break is 14% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1120 CARB-QT 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 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
1120 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 1120 CARB-QT takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability6
1120 CARB-QT's machinability is poor (25/100, worse than 93% of steel grades); weldability poor (15/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1120 CARB-QT
Is 1120 easy to machine?
Excellent screw-machine steel — MnS inclusions break chips; run high speeds with sulfurized cutting oil, expect ~80 % of 1212 productivity.
Can 1120 be welded?
Weldable with low-hydrogen processes but sulfur promotes hot/solidification cracking; avoid structural welds or use filler with high Mn and preheat.
Can 1120 be formed, bent or molded?
Only light cold bending and moderate upsetting; sulfide stringers cause splitting in tight-radius transverse bends — anneal or hot form for severe shapes.
What surface finishes work on 1120?
No natural corrosion resistance: use zinc or zinc-nickel plating, black oxide, phosphate-and-oil or paint; inclusions can leave pits after bright polishing or plating.
1120 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 | 0.18 – 0.23 | 0.2 |
| Mn | 0.7 – 1 | 0.85 |
| P | ≤ 0.04 | 0.02 |
| Sresulfurized for machinability | 0.08 – 0.13 | 0.1 |
| Fe | balance | — |
1120 CARB-QT — frequently asked
What is 1120 CARB-QT used for?
1120 CARB-QT is typically used for fittings, shafts and fasteners. In short: higher carbon than 1119; 76 machinability rating; general screw-machine bar.
What is the yield strength of 1120 CARB-QT?
1120 CARB-QT has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 1120 CARB-QT easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of steel grades). Excellent screw-machine steel — MnS inclusions break chips; run high speeds with sulfurized cutting oil, expect ~80 % of 1212 productivity.
Can 1120 CARB-QT be welded?
Not readily — weldability is rated poor (15/100). Weldable with low-hydrogen processes but sulfur promotes hot/solidification cracking; avoid structural welds or use filler with high Mn and preheat.
What surface finishes work on 1120 CARB-QT?
No natural corrosion resistance: use zinc or zinc-nickel plating, black oxide, phosphate-and-oil or paint; inclusions can leave pits after bright polishing or plating.
Can 1120 CARB-QT be formed, bent or molded?
Only light cold bending and moderate upsetting; sulfide stringers cause splitting in tight-radius transverse bends — anneal or hot form for severe shapes.
What is the maximum service temperature of 1120 CARB-QT?
1120 CARB-QT 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 1120-CD and 1120-A?
CD is the default condition — standard stocked condition: good size tolerance, straightness and the best chip control on screw machines. A: softest condition for heavy cold forming, heading or deep boring before hardening. Yield strength is 395 MPa in CD versus 220 MPa in A.
Sources
- SAE J403 — Chemical Compositions of SAE Carbon Steels — SAE International (2014)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — 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)
- Machinery's Handbook (machinability ratings, free-machining steels) — Industrial Press (2020)
- GB/T 8731 (Y20 comparable grade) — SAC (2008)
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.