Steel 1021 CARB-Q&T
Heat-treated state
AISI/SAE 1021 · UNS G10210
Use for gears, pins and bushings needing a hard wear-resistant case (58–62 HRC) over a tough low-carbon core.
Values for the CARB-Q&T condition
Other 1021 tempers and conditions
1021 is listed in 6 conditions; see the grade overview at 1021.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled | Lowest-cost condition for structural and weld-fabricated parts where scale and loose tolerances are acceptable. | 220 | 400 | 25 | 116 HB | — |
Solution annealed | Choose for maximum ductility before deep drawing, severe cold forming or heavy machining of forgings. | 295 | 395 | 36 | 111 HB | — |
Normalized | Use to refine grain and homogenize forgings/weldments, giving a good strength–toughness balance. | 330 | 445 | 33 | 131 HB | — |
Cold Drawn, Stress Relieved | Pick when machined parts must stay straight — residual drawing stresses are removed with only slight strength loss. | 345 | 430 | 18 | 126 HB | 10.8 % IACS |
CDDefault Cold drawn | Default stock condition for round/square bar: tighter tolerances, smooth finish and higher strength than hot rolled. | 385 | 455 | 15 | 131 HB | — |
CARB-Q&TThis page case hardened | Use for gears, pins and bushings needing a hard wear-resistant case (58–62 HRC) over a tough low-carbon core. | 400 | 600 | 18 | 60 HRC | 9 % IACS |
What is 1021 CARB-Q&T?
1021 CARB-Q&T is 1021 heat treated to CARB-Q&T — use for gears, pins and bushings needing a hard wear-resistant case (58–62 HRC) over a tough low-carbon core. 1021 CARB-Q&T has a yield strength of 400 MPa (58 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 60% of steel grades. Elongation at break is 18% and the elastic modulus is 200 GPa (29 Msi). 1021 CARB-Q&T has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 92% of steel grades. It melts at 1,425°C (2,597 °F). CD is the default condition FabDigit quotes; CARB-Q&T is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
Limitations
- 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 formability — 12/100, worse than 92% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
1021 CARB-Q&T properties
Typical room-temperature values for 1021 CARB-Q&T; 22 are specific to this condition. Other listed values are 1021 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
1021 CARB-Q&T has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 92% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
1021 CARB-Q&T has a yield strength of 400 MPa (58 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 60% of steel grades. Elongation at break is 18% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1021 CARB-Q&T is rated for continuous service to 180°C (356 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
1021 CARB-Q&T conducts electricity at 9 % IACS, better than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 1021 CARB-Q&T 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
1021 CARB-Q&T's machinability is poor (25/100, worse than 93% of steel grades); weldability poor (30/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1021 CARB-Q&T
Is 1021 easy to machine?
Machines easily but gummy — use sharp positive-rake tooling, high speed and good coolant; cold-drawn bar gives better chip control and finish than hot rolled.
Can 1021 be welded?
Excellent weldability by SMAW/GMAW/GTAW/RSW with ER70S-x or E70xx filler; no preheat required below ~25 mm, keep interpass clean and dry.
Can 1021 be formed, bent or molded?
Very good cold formability — bending, roll forming, heading and drawing; anneal or normalize before severe forming and allow for springback.
What surface finishes work on 1021?
No natural corrosion protection: zinc plate, black oxide, phosphate + oil, hot-dip galvanize or paint; takes a decent ground/polished finish but not mirror bright.
1021 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 heat analysis | 0.18 – 0.23 | 0.2 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.04 | — |
| S | ≤ 0.05 | — |
| Fe | balance | — |
1021 CARB-Q&T — frequently asked
What is 1021 CARB-Q&T used for?
1021 CARB-Q&T is typically used for bolts, studs, machine parts, cold-headed fasteners and light structural parts. In short: higher-manganese 1020 variant; excellent weldability; good cold-heading grade.
What is the yield strength of 1021 CARB-Q&T?
1021 CARB-Q&T has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 1021 CARB-Q&T easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of steel grades). Machines easily but gummy — use sharp positive-rake tooling, high speed and good coolant; cold-drawn bar gives better chip control and finish than hot rolled.
Can 1021 CARB-Q&T be welded?
Not readily — weldability is rated poor (30/100). Excellent weldability by SMAW/GMAW/GTAW/RSW with ER70S-x or E70xx filler; no preheat required below ~25 mm, keep interpass clean and dry.
What surface finishes work on 1021 CARB-Q&T?
No natural corrosion protection: zinc plate, black oxide, phosphate + oil, hot-dip galvanize or paint; takes a decent ground/polished finish but not mirror bright.
Can 1021 CARB-Q&T be formed, bent or molded?
Very good cold formability — bending, roll forming, heading and drawing; anneal or normalize before severe forming and allow for springback.
What is the maximum service temperature of 1021 CARB-Q&T?
1021 CARB-Q&T 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 1021-CD and 1021-HR?
CD is the default condition — default stock condition for round/square bar: tighter tolerances, smooth finish and higher strength than hot rolled. HR: lowest-cost condition for structural and weld-fabricated parts where scale and loose tolerances are acceptable. Yield strength is 385 MPa in CD versus 220 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 — 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.4 — Heat Treating — ASM International (1991)
- GB/T 699 — (20Mn) — SAC (2015)
- Mysteel / SMM (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.