Steel CQ15 · heat-treated state
Steel CQ15 Carburized
Properties of the Carburized condition, compared with the other CQ15 tempers.
Choose when a wear-resistant hard case over a tough low-carbon core is needed (pins, small gears, self-drilling screws).
What is CQ15 Carburized?
CQ15 Carburized is CQ15 heat treated to Carburized — choose when a wear-resistant hard case over a tough low-carbon core is needed (pins, small gears, self-drilling screws). CQ15 Carburized has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 60% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi). CQ15 Carburized has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 91% of steel grades. It melts at 1,470°C (2,678 °F). HR is the default condition FabDigit quotes; Carburized is available on request or by drawing note.
Advantages
- Readily welded — 95/100, better than 97% of steel grades
- Conducts heat well — 51.9 W/m·K (30 BTU/hr·ft·°F), better than 96% of steel grades
- High electrical conductivity — 10.8 % IACS, better than 94% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
Limitations
- Limited formability — 10/100, worse than 94% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
CQ15 Carburized properties
Typical room-temperature values for CQ15 Carburized — 8 properties are specific to this condition; the rest are grade-level values shared by every CQ15 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
CQ15 Carburized has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 91% of steel grades. It melts at 1,470°C (2,678 °F).
Mechanical13
CQ15 Carburized has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 60% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
CQ15 Carburized is rated for continuous service to 400°C (752 °F). It conducts heat at 51.9 W/m·K (30 BTU/hr·ft·°F), better than 96% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
CQ15 Carburized conducts electricity at 10.8 % IACS, better than 94% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 87% of steel grades.
Sustainability4
Producing a kilogram of CQ15 Carburized takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability6
CQ15 Carburized's machinability is good (55/100, better than 62% of steel grades); weldability excellent (95/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other CQ15 tempers and conditions
CQ15 is also supplied in 6 other conditions. The full side-by-side table is on the CQ15 overview.
- HRDefaultCheapest as-supplied condition for structural stampings, weldments and as feedstock for cold drawing.190 MPa yield · 101 HB
- CarburizedChoose when a wear-resistant hard case over a tough low-carbon core is needed (pins, small gears, self-drilling screws).480 MPa yield · 60 HRC
- CDCold-work strengthened condition for bright bar, shafts and screws formed with modest deformation.360 MPa yield · 126 HB
- GalvanizedUse when bare part must resist outdoor/humid corrosion without painting; zinc layer limits welding and high-temperature use.230 MPa yield · 100 HB
- CRPick for clean surface, tight thickness tolerance and deep-drawn or bent stampings.210 MPa yield · 95 HB
- AnnealedSoftest condition, chosen for severe multi-station cold heading and thread rolling of fasteners.200 MPa yield · 92 HB
Working with CQ15 Carburized
Is CQ15 easy to machine?
Soft and gummy — use sharp positive-rake tools, high speed with coolant to avoid built-up edge; cold-drawn condition machines noticeably better than annealed.
Can CQ15 be welded?
Excellent weldability by all arc, resistance and MIG/spot processes with no preheat or PWHT below ~25 mm; remove zinc coating locally and ventilate when welding galvanized material.
Can CQ15 be formed, bent or molded?
Outstanding cold formability — suited to deep drawing, multi-station cold heading and thread rolling; interstage spheroidize annealing recommended for reductions above ~70 %.
What surface finishes work on CQ15?
Not anodizable; protect with hot-dip or electro-galvanizing, zinc-nickel, phosphate + paint or e-coat; rusts within days if stored bare and unoiled.
CQ15 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 |
|---|---|---|
| C0.15 % nominal; CHQ grades often held to a narrower ±0.02 range | 0.12 – 0.18 | 0.15 |
| Mn | 0.3 – 0.6 | 0.45 |
| Sikept low for cold heading; Si-killed variants up to 0.30 | ≤ 0.1 | 0.05 |
| P | ≤ 0.03 | 0.02 |
| Slow S preferred for CHQ to avoid heading cracks | ≤ 0.04 | 0.02 |
| Alaluminium-killed, fine grain | 0.02 – 0.07 | 0.04 |
| Nlow free N to avoid ageing | ≤ 0.01 | 0.01 |
| Curesidual | ≤ 0.2 | 0.05 |
| Fe | balance | — |
CQ15 Carburized — frequently asked
What is CQ15 Carburized used for?
CQ15 Carburized is typically used for fasteners, bolts and studs. In short: cold-heading low-carbon wire.
What is the yield strength of CQ15 Carburized?
CQ15 Carburized has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 60% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is CQ15 Carburized easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Soft and gummy — use sharp positive-rake tools, high speed with coolant to avoid built-up edge; cold-drawn condition machines noticeably better than annealed.
Can CQ15 Carburized be welded?
Yes — weldability is rated excellent (95/100). Excellent weldability by all arc, resistance and MIG/spot processes with no preheat or PWHT below ~25 mm; remove zinc coating locally and ventilate when welding galvanized material.
What surface finishes work on CQ15 Carburized?
Not anodizable; protect with hot-dip or electro-galvanizing, zinc-nickel, phosphate + paint or e-coat; rusts within days if stored bare and unoiled.
Can CQ15 Carburized be formed, bent or molded?
Outstanding cold formability — suited to deep drawing, multi-station cold heading and thread rolling; interstage spheroidize annealing recommended for reductions above ~70 %.
What is the maximum service temperature of CQ15 Carburized?
CQ15 Carburized 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 CQ15-HR and CQ15-CD?
HR is the default condition — cheapest as-supplied condition for structural stampings, weldments and as feedstock for cold drawing. CD: cold-work strengthened condition for bright bar, shafts and screws formed with modest deformation. Yield strength is 190 MPa in HR versus 360 MPa in CD.
Can FabDigit make parts in CQ15 Carburized?
Yes — CQ15 Carburized is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A1011/A1008 (CS Type B hot- and cold-rolled sheet) — ASTM (2018)
- ASTM A510 / SAE J403 (grade 1015 wire rod and bar) — ASTM/SAE (2018)
- GB/T 6478 / GB/T 700 Q195-Q215 — SAC (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- Mysteel / 1688 — 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.